CN115703970A - Liquid crystal aligning agent for photo-alignment, liquid crystal alignment film and method for producing same, and liquid crystal element - Google Patents

Abstract

The invention provides a liquid crystal alignment film which can form a liquid crystal display element with good contrast and excellent display quality even under the condition of low exposure energy of photo-alignment treatment, a manufacturing method thereof, a photo-alignment liquid crystal alignment agent capable of forming the liquid crystal alignment film and a liquid crystal element. A liquid crystal aligning agent for photo-alignment comprising at least one polymer and a solvent, wherein,at least one of the polymers is a polymer obtained by reacting a tetracarboxylic acid dianhydride with a diamine, and a raw material composition used as a raw material of the polymer obtained by reacting the tetracarboxylic acid dianhydride with the diamine contains at least one of the compounds represented by the formula (1-1) or (1-2) and a compound having a photoreactive structure which imparts liquid crystal alignment properties to an alignment film by photoreaction.

Description

Liquid crystal aligning agent for photo-alignment, liquid crystal aligning film, manufacturing method thereof, and liquid crystal element

technical field

The invention relates to a liquid crystal aligning agent, a liquid crystal aligning film and a manufacturing method thereof, and a liquid crystal element using the liquid crystal aligning film. Specifically, it relates to a liquid crystal aligning agent for photo-alignment (hereinafter, sometimes abbreviated as liquid crystal aligning agent) for forming a liquid crystal aligning film of a photo-alignment method (hereinafter, sometimes simply referred to as a photo-alignment film), and a liquid crystal aligning agent for use. A liquid crystal aligning film of a photo-alignment method formed by using the liquid crystal aligning agent and a liquid crystal display element having the liquid crystal aligning film.

Background technique

There is known a liquid crystal element, which can cause optical phenomena such as refraction, scattering, and reflection caused by electromagnetic waves incident into the element by controlling or modulating the alignment state of the liquid crystal layer in the element. Specifically, liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters are known in addition to the following liquid crystal display elements.

As liquid crystal display elements, there are known twisted nematic (Twisted Nematic, TN) mode, super twisted nematic (Super Twisted Nematic, STN) mode, in-plane switching (In-Plane Switching, IPS) mode, fringe field switching (Fringe Liquid crystal display elements of various drive methods such as Field Switching (FFS) mode, Vertical Alignment (Vertical Alignment, VA) (Multi-domain Vertical Alignment) mode of a vertical alignment type. These liquid crystal display elements are used in image display devices of various electronic devices such as televisions and mobile phones, and are being developed with the aim of further improving display quality. Specifically, the improvement of the performance of a liquid crystal display element can be achieved not only by the improvement of a drive method and an element structure, but also by the structural member used for an element. Moreover, among the structural members used in liquid crystal display elements, especially liquid crystal alignment films are one of the important materials related to display quality. Actively conduct research.

Here, the liquid crystal alignment film is provided on a pair of substrates provided on both sides of the liquid crystal layer of the liquid crystal display element in contact with the liquid crystal layer. function. By using the liquid crystal aligning film with high liquid-crystal orientation, the liquid crystal display element which has high contrast and improved afterimage characteristics can be realizable (for example, refer patent document 1 and patent document 2).

In formation of such a liquid crystal aligning film, the solution (varnish) which melt|dissolved polyamic acid, soluble polyimide, or polyamic acid ester in an organic solvent is mainly used at present. When forming a liquid crystal aligning film using these varnishes, the varnish is coated on a substrate, and then the coating film is cured by heating to form a polyimide-based liquid crystal aligning film, and orientation suitable for the display mode is performed as necessary. deal with. As the orientation treatment method, there are known: a rubbing method in which the orientation of the polymer molecules is adjusted by rubbing the surface of the orientation film with cloth or the like; and photoisomerization or A photo-alignment method that imparts anisotropy to the film through photochemical changes such as dimerization. Compared with the rubbing method, the photo-alignment method has higher orientation uniformity and is a non-contact orientation treatment method, so it has the advantages of not damaging the film, It can reduce the causes of poor display of liquid crystal display elements such as dust and static electricity.

As a liquid crystal aligning film using such a photo-alignment method, for example, Patent Documents 1 to 6 describe: using diaminoazobenzene or the like as a raw material and applying photoisomerization technology to obtain anchoring energy A large photo-alignment film with good liquid crystal orientation.

[Prior art literature]

[Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-197999

[Patent Document 2] International Publication No. 2013/157463

[Patent Document 3] Japanese Patent Laid-Open No. 2005-275364

[Patent Document 4] Japanese Patent Laid-Open No. 2007-248637

[Patent Document 5] Japanese Patent Laid-Open No. 2009-069493

[Patent Document 6] International Publication No. 2015/016118

Contents of the invention

[Problem to be Solved by the Invention]

In recent years, liquid crystal display elements have been used in monitors for personal computers, liquid crystal televisions, mobile phones, display parts of smartphones, and monitors for medical use. Further, more excellent display quality is required, and contrast ratio is cited as an important characteristic affecting display quality. In addition, in a liquid crystal display element using a liquid crystal alignment film using a photo-alignment method, in order to improve the production efficiency of the liquid crystal display element, it is required to use a liquid crystal alignment film that can be used even in a short photo-alignment treatment time, that is, a photo-alignment film with less exposure energy. During processing, good contrast can also be exhibited.

Therefore, the present inventors provide a liquid crystal aligning film that can form a liquid crystal display element having a good contrast and excellent display quality even when the exposure energy of the photo-alignment treatment is lower than before, and provides a The liquid crystal aligning agent for photo-alignment which can form such a liquid crystal aligning film has been earnestly researched.

[Technical means to solve the problem]

As a result of diligent research to solve the above problems, the present inventors have found that an alignment film having high liquid crystal orientation can be obtained by using a compound represented by formula (1-1) or formula (1-2), and The present invention has been accomplished by using the alignment film, which has a favorable contrast and can form a liquid crystal display element excellent in display quality.

The present invention includes the following structures.

[1] A liquid crystal aligning agent for photo-alignment, comprising at least one polymer and a solvent, and in the liquid crystal aligning agent for photo-alignment, at least one of the polymers is a mixture of tetracarboxylic dianhydrides and two Polymers formed by the reaction of amines,

Formula (1-1) or formula (1-2) is contained in the raw material composition used as the raw material of the said polymer which made the said tetracarboxylic dianhydrides and the said diamines react. A compound having a photoreactive structure that imparts liquid crystal orientation to the alignment film by photoreaction with at least one of the compounds.

[2] The liquid crystal aligning agent for photo-alignment according to item 1, wherein the photo-reaction is at least one of photo-isomerization, photo-Friesian rearrangement, photo-decomposition, and photo-dimerization.

[3] The liquid crystal aligning agent for photo-alignment according to item 1 or item 2, wherein the compound having the photoreactive structure is at least one type of compound represented by formula (2).

In formula (2), X is an alkylene group having 1 to 12 carbon atoms, and when the alkylene group has 2 or more carbon atoms, non-adjacent -(CH ₂ ) ₂ - of the alkylene group More than one can be substituted by -O- or -NH-,

R ^a and R ^b are independently hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, methoxycarbonyl, or one represented by formula (P1-1) or formula (P1-2). price base,

R ^c are each independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, or a monovalent group represented by formula (P1-1) or formula (P1-2), and j is 0 or 1 , a~c are independently integers of 0~2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkanoyl, Or substituted or unsubstituted alkoxycarbonyl, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * represents the bonding position on the benzene ring in formula (2),

In formula (2), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary.

[4] The liquid crystal aligning agent for photo-alignment as described in item 3 whose compound represented by the said formula (2) is any one of formula (2-1) - a formula (2-3).

In formula (2-1), R ^1a and R ^1c independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2),

In formula (2-2), R ^2a and R ^2b independently represent a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), and R ^2c independently represent a hydrogen atom, a group, methoxy group, trifluoromethyl group, fluorine atom, _X1 is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the -(CH ₂ ) More than one non-adjacent _2- can be substituted by -O- or -NH-, k is an integer from 0 to 2,

In formula (2-3), R ^3a each independently represents a hydrogen atom or a monovalent group represented by formula (P1-1) or formula (P1-2), R ⁴ and R ⁵ are each independently a hydrogen atom or fluorine Atoms, ^R4 and ^R5 will not be hydrogen atoms at the same time, ^R3c is independently a hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, _X1 is an alkylene group with 1 to 12 carbons , when the carbon number of the alkylene group is 2 or more, one or more non-adjacent -(CH ₂ ) ₂ - of the alkylene group may be substituted by -O- or -NH-, m is 0～ an integer of 2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkanoyl, Or substituted or unsubstituted alkoxycarbonyl, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * is represented in formula (2-1), formula (2-2) and formula (2- 3) the bonding position on the benzene ring,

In formula (2-1), formula (2-2) and formula (2-3), the bonding position is not fixed on any carbon atom that constitutes the ring and represents that the bonding position on the ring is arbitrary .

[5] The liquid crystal aligning agent for photo-alignment according to item 1 or item 2, wherein the compound having the photoreactive structure is at least one type of compound represented by formula (3).

In formula (3), R ¹ and R ² independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons or an alkoxy group with 1 to 6 carbons, R ¹ and ^R2 can be integrated to form a substituted methylene group, and X each independently represent a halogen atom, an alkyl group with 1 to 6 carbons, a haloalkyl group with 1 to 6 carbons, or an alkane with 1 to 6 carbons Oxygen group, n independently represent the integer of 0-4.

[6] The liquid crystal aligning agent for photo-alignment according to any one of Item 1 to Item 5, further comprising an additive.

[7] The liquid crystal aligning agent for photo-alignment according to item 6, wherein the additive is at least one selected from the group consisting of oxazoline compounds and epoxy compounds.

[8] A liquid crystal aligning film formed from the liquid crystal aligning agent for photo-alignment according to any one of Item 1 to Item 7.

[9] A liquid crystal element having the liquid crystal aligning film according to item 8.

[10] A method of manufacturing a liquid crystal alignment film, comprising: applying the liquid crystal alignment agent for photo-alignment according to any one of items 1 to 7 to a substrate; and irradiating polarized ultraviolet rays to the coating film process.

[Effect of the invention]

By using the liquid crystal aligning agent for photo-alignment of this invention, even when the exposure energy of a photo-alignment process is little, the liquid crystal aligning film which has high liquid crystal orientation property can be obtained. Furthermore, by using the said liquid crystal aligning film, manufacture of the liquid crystal display element which has favorable contrast and is excellent in display quality can be realized efficiently.

Detailed ways

Hereinafter, the present invention will be described in detail. The description of the constituent requirements described below may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. The "liquid crystal aligning agent" in the present invention is a liquid crystal aligning agent that can impart anisotropy by irradiating polarized ultraviolet rays when forming its film on a substrate. In this specification, if it is sometimes simply referred to as "liquid crystal aligning agent", then It may also be called a "liquid crystal aligning agent for photo-alignment". In addition, in this invention, a "tetracarboxylic dianhydride" means a tetracarboxylic dianhydride, a tetracarboxylic diester, or a tetracarboxylic-acid diester dihalide. In addition, in the present invention, diamines and dihydrazides may also be referred to as "diamines".

<The liquid crystal aligning agent for photo-alignment of this invention>

The liquid crystal aligning agent for photo-alignment of the present invention is characterized in that it contains at least one selected from the group consisting of polyamic acid and polyamic acid derivatives obtained by reacting tetracarboxylic dianhydrides and diamines. A polymer, as a raw material of the polymer, includes at least one of the compounds represented by formula (1-1) or formula (1-2) and has a photoreactive compound that imparts liquid crystal orientation to the alignment film through photoreaction. Structured compounds. In the present invention, the polyamic acid derivatives refer to polyimides, partial polyimides, polyamic acid esters, polyamic acid-polyamide copolymers, and polyamideimides. Such polymers are sometimes referred to as polymers of the present invention.

<Compound represented by formula (1-1) or formula (1-2)>

The compound represented by formula (1-1) or formula (1-2) used for the polymer contained in the liquid crystal aligning agent of this invention is demonstrated.

The total amount of tetracarboxylic dianhydrides used in the polymer contained in the liquid crystal aligning agent of the present invention may be a compound represented by formula (1-1) or formula (1-2), and may also be used in combination with formula ( A compound represented by 1-1) and a compound represented by formula (1-2). Furthermore, other tetracarboxylic dianhydrides described below may also be used in combination, and in that case, the content of other tetracarboxylic dianhydrides is preferably 5 mol with respect to the total amount of tetracarboxylic dianhydrides in the monomer % or more, more preferably 20 mol% to 80 mol%.

In the molecular structure of the compound represented by the formula (1-1) or the compound represented by the formula (1-2), two dicarboxylic acid anhydride skeletons exist in the exo form (exo) with respect to the norbornane rings respectively bonded. s position. With respect to the compound represented by formula (1-1) or the compound represented by formula (1-2), there is one or two dicarboxylic acid anhydride skeletons that exist in the endotype (endo) relative to the bonded norbornane ring. ) positional stereoisomers. In the polymer using the compound represented by the formula (1-1) and the polymer using the compound represented by the formula (1-2), compared with the case of using these stereoisomers, the liquid crystal is formed by the orientation treatment. The anisotropy shown in an alignment film is larger, and it is more excellent from a viewpoint of a liquid crystal orientation.

＜Compounds with a photoreactive structure＞

The compound which has a photoreactive structure used as a raw material of the polymer contained in the liquid crystal aligning agent of this invention is demonstrated. In the present specification, the term "photoreactive structure" refers to a structure that causes a photoreaction by irradiating light including a specific wavelength band corresponding to the photoreactive structure. Examples of photoreactions include photoisomerization, photo-Friesian rearrangement, photolysis, and photodimerization. By using a compound having a photoreactive structure as a raw material, a photoreactive structure can be incorporated into the polymer. In addition, regarding the compounds listed as compounds having a photoreactive structure in this specification, when the process of forming an alignment film from a liquid crystal aligning agent is not irradiated with light containing a unique wavelength band corresponding to the photoreactive structure In some cases, it can also be used as a raw material as a compound not having a photoreactive structure.

When the coating film containing the liquid crystal aligning agent for photo-alignment of the present invention is irradiated with polarized light of a predetermined wavelength in the process of forming the liquid crystal aligning film, the photoreactive structure of the polymer chain approximately parallel to the direction of the polarized light causes a photoreaction Components facing a specific direction (direction substantially perpendicular to the polarization direction of irradiated light) among the polymer chains are dominant, whereby an anisotropic coating film can be obtained. A state in which a component facing a specific direction in the polymer chain dominates is expressed as that the polymer chain is oriented. When the photo-alignment film formed by calcining the anisotropic coating film is used in a liquid crystal display element, the result of the interaction between the surface of the film after alignment and the liquid crystal molecules is that the liquid crystal molecules are aligned in a certain direction ( Orientation is performed by aligning the major axes in a direction substantially perpendicular to the polarization direction of the irradiated light.

＜Structure that causes photoisomerization reaction＞

As an example of the structure which causes photoisomerization reaction in this invention, the structure which has an azobenzene skeleton is mentioned. In this specification, the structure which has an azobenzene skeleton means the structure represented by following formula (A).

In formula (A), * is a bonding bond, and the bonding position of the bonding bond with respect to the benzene ring is each independently arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted by a substituent.

Specifically, the compound which has an azobenzene structure used for the polymer contained in the liquid crystal aligning agent for photo-alignment of this invention is a compound represented by formula (2).

In formula (2), X is an alkylene group having 1 to 12 carbon atoms, and when the alkylene group has 2 or more carbon atoms, non-adjacent -(CH ₂ ) ₂ - of the alkylene group More than one can be substituted by -O- or -NH-,

R ^a and R ^b are independently hydrogen atom, methyl, methoxy, trifluoromethyl, fluorine atom, methoxycarbonyl, or one represented by formula (P1-1) or formula (P1-2). A valent group, R ^c is independently a hydrogen atom, a methyl group, a methoxyl group, a trifluoromethyl group, a fluorine atom, or a monovalent group represented by formula (P1-1) or formula (P1-2), and j is 0 or 1, a～c are each independently an integer of 0～2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkanoyl, Or substituted or unsubstituted alkoxycarbonyl, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * represents the bonding position on the benzene ring in formula (2),

In formula (2), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary.

Specifically, the compound represented by formula (2) is a compound represented by following formula (2-1) - a formula (2-3).

In formula (2-1), R ^1a and R ^1c independently represent a monovalent group represented by a hydrogen atom, formula (P1-1) or formula (P1-2),

In formula (2-2), R ^2a and R ^2b independently represent a hydrogen atom, a monovalent group represented by formula (P1-1) or formula (P1-2), and R ^2c independently represent a hydrogen atom, a group, methoxy group, trifluoromethyl group, fluorine atom, _X1 is an alkylene group with 1 to 12 carbons, and when the carbon number of the alkylene group is 2 or more, the -(CH ₂ ) More than one non-adjacent _2- can be substituted by -O- or -NH-, k is an integer from 0 to 2,

In formula (2-3), R ^3a each independently represents a hydrogen atom, a monovalent group represented by formula (P1-1) or formula (P1-2), R ⁴ and R ⁵ are each independently a hydrogen atom or - F, R ⁴ and R ⁵ do not become hydrogen atoms at the same time, R ^3c are independently hydrogen atoms, methyl groups, methoxy groups, trifluoromethyl groups, and fluorine atoms, and X ₁ is an alkylene group with 1 to 12 carbons , when the carbon number of the alkylene group is 2 or more, one or more non-adjacent -(CH ₂ ) ₂ - of the alkylene group may be substituted by -O- or -NH-, m is 0～ an integer of 2,

In formula (P1-1) and formula (P1-2), R ^6a , R ^7a and R ^8a independently represent a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkanoyl, Or substituted or unsubstituted alkoxycarbonyl, R ^6a , R ^7a and R ^8a may be the same as or different from each other, * is represented in formula (2-1), formula (2-2) and formula (2- 3) the bonding position on the benzene ring,

In formula (2-1), formula (2-2) and formula (2-3), the bonding position is not fixed on any carbon atom that constitutes the ring and represents that the bonding position on the ring is arbitrary .

Specific examples of the compound represented by formula (2-1) include the following compounds.

In formula (2-1-2), R ^6a is an alkyl group having 1 to 4 carbon atoms.

Specific examples of the compound represented by formula (2-2) include the following compounds.

In formulas (2-2-1) to (2-2-6), R ^6a is an alkyl group having 1 to 4 carbon atoms, l is an integer of 1 to 10, and m is an integer of 1 to 11.

Specific examples of the compound represented by formula (2-3) include the following compounds.

In formula (2-3-1) and formula (2-3-2), l is an integer of 1-10.

When paying attention to the transparency of the formed liquid crystal aligning film, it is preferable to use formula (2-1-2), formula (2-1-3), formula (2-2-3), formula (2) -2-4), any one or more of the compounds in the group consisting of formula (2-2-5) and formula (2-2-6), more preferably formula (2-1-2) or formula (2-1-3), particularly preferably a compound in which R ^6a in formula (2-1-2) is ethyl.

When paying attention to obtaining a liquid crystal aligning film (that is, a liquid crystal aligning agent with high sensitivity) that can form an element with good afterimage characteristics even if the energy is small, it is preferable to use the liquid crystal aligning agent selected from the formula (2-1- 2), formula (2-1-3), formula (2-2-3), formula (2-2-4), formula (2-2-5), formula (2-2-6), formula ( Any one or more of the compounds in the group consisting of 2-3-1) and formula (2-3-2), more preferably formula (2-1-2), formula (2-3-1) or Formula (2-3-2), more preferably a compound in which R ^6a is ethyl in formula (2-1-2) or a compound represented by 1=2 to 6 in formula (2-3-1).

When paying attention to obtaining a liquid crystal display element that can maintain a high voltage holding ratio (that is, VHR (Voltage Holding Ratio) is excellent in reliability) even if it is used for a long time, it is preferable to use a liquid crystal display element selected from the formula (2-1-2), the formula ( 2-1-3), formula (2-2-1), formula (2-2-2), formula (2-2-3), formula (2-2-4), formula (2-2-5 ) and any one or more of the compounds in the group consisting of formula (2-2-6), more preferably formula (2-1-2), formula (2-1-3) or formula (2-2 -1) the compound represented by l=2～6, and more preferably in the formula (2-1-2) R ^6a is the compound represented by ethyl or the formula (2-2-1) represented by l=2～6 compound of.

In the case where emphasis is placed on obtaining a liquid crystal display element with higher contrast, it is more preferable to use a compound selected from the group consisting of formula (2-1-1), formula (2-2-1) and formula (2-2-2). Any one or more of the compounds in the group is more preferably a compound represented by 1=2 to 6 in formula (2-1-1) or formula (2-2-1). In said case, relative to the total amount of diamine in the monomer, the diamine in the polymer is selected from formula (2-1-1), formula (2-2-1) and formula (2-2-2). The total content of the compounds in the group formed is preferably 20 mol% to 100 mol%, more preferably 40 mol% to 100 mol%.

<Compounds having a structure that causes photo-Friesian rearrangement>

As an example of the structure which causes photofriesian rearrangement reaction in this invention, the structure which has a phenyl ester skeleton is mentioned. The structure which has a phenyl ester skeleton in this specification means the structure represented by following formula (B).

In the formula (B), * is a bonding bond, the bonding position of the bonding bond with respect to the benzene ring is arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted with a substituent. The following formula (3) is mentioned as a preferable example of the compound which has the structure which causes photofries rearrangement used for the polymer contained in the liquid crystal aligning agent of this invention. In addition, as a compound having a structure causing a photo-Friesian rearrangement reaction, formula (AN-4-32) to formula (AN-4-36), formula (DI-5-32), formula (DI -5-33), the compound represented by formula (DI-5-35) and formula (DI-6-8) to formula (DI-6-10).

In formula (3), R ¹ and R ² independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbons, a haloalkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons. R ¹ and R ² may be united to form an optionally substituted methylene group. X each independently represents a halogen atom, an alkyl group having 1 to 6 carbons, a haloalkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons, and n represents an integer of 0 to 4. m in the formula (DI-5-35) represents an integer of 0 to 12.

Among these compounds, from the viewpoint of producing a high-contrast liquid crystal display element, it is preferable to use the compound represented by formula (3), and it is more preferable to use the amino group on each benzene ring in formula (3) relative to the ester group. Para compound.

The total content of the compounds represented by the formula (3) is preferably 40 mol % to 100 mol %, more preferably 70 mol % to 100 mol %, based on the total amount of diamines in the monomer.

Specific examples of the compound represented by the formula (3) include compounds represented by the following formulas (3-1) to (3-6).

＜Structure that causes photolysis reaction＞

As an example of the structure which causes a photolysis reaction in this invention, the structure which has a cyclobutane tetracarboxylic-acid skeleton is mentioned. In this specification, the structure which has a cyclobutane tetracarboxylic-acid skeleton means the structure represented by following formula (C).

In formula (C), *1, *1', *2 and *2' are bonding bonds, and any group or two groups of *1 and *1' group and *2 and *2' group can be combined with the same O bond. That is, acid anhydride -CO-O-CO- can be formed. R ^b1 , R ^b2 , R ^b3 and R ^b4 are each independently a monovalent organic group.

Preferred examples of the compound having a structure that causes a photodecomposition reaction used in the polymer contained in the liquid crystal aligning agent of the present invention include those represented by the following formulas (PA-1) to (PA-6) compound of.

In formulas (PA-3) to (PA-6), R ¹¹ is independently an alkyl group having 1 to 5 carbon atoms.

＜Structure that causes photodimerization reaction＞

As an example of the structure which causes photodimerization reaction in this invention, the structure which has a cinnamic-acid skeleton is mentioned. In this specification, the structure which has a cinnamic acid skeleton means the structure represented by following formula (D).

In the formula (D), * is a bonding bond, the bonding position of the bonding bond with respect to the benzene ring is arbitrary, and the substitutable hydrogen atom of the benzene ring may be substituted with a substituent.

As a preferable example of the compound which has the structure which causes photodimerization reaction used for the polymer contained in the liquid crystal aligning agent of this invention, the following formula (PDI-9) - formula (PDI-13) can be mentioned indicated compound.

In the formula (PDI-12), R ¹² is an alkyl or alkoxy group having 1 to 10 carbon atoms, and at least one hydrogen atom of the alkyl or alkoxy group may be substituted by a fluorine atom.

＜Types of polymers＞

Hereinafter, polyamic acid and polyamic acid derivatives are demonstrated in detail.

Here, polyamic acid is a polymer synthesized by the polymerization reaction of diamines represented by formula (DI) and tetracarboxylic dianhydride represented by formula (AN), and has a structure represented by formula (PAA). unit. When the liquid crystal alignment agent containing polyamic acid is heated and calcined in the process of forming a liquid crystal alignment film, the polyamic acid is imidized to form a polyimide liquid crystal alignment agent having a structural unit represented by formula (PI) membrane.

In formula (AN), formula (PAA) and formula (PI), X ¹ is a tetravalent organic group. In formula (DI), formula (PAA) and formula (PI), X ² is a divalent organic group. For the preferred range and specific examples of the tetravalent organic group in ^X1 , refer to the structure corresponding to the formula (1) or the tetracarboxylic dianhydride described in the column of other tetracarboxylic dianhydrides below. For the preferred range and specific examples of the divalent organic group in X ² , refer to the description related to the structure corresponding to the diamine or dihydrazide described in the formula (2) or other diamines below.

A polyamic acid derivative is a compound whose characteristics were changed by substituting a part of polyamic acid with another atom or an atomic group, and the polyamic acid derivative which improved the solubility to the solvent used for a liquid crystal aligning agent is especially preferable. Specific examples of such polyamic acid derivatives include: 1) polyimide in which all the amino groups and carboxyl groups of the polyamic acid undergo a dehydration ring-closure reaction; Polyimide, 3) polyamic acid ester obtained by converting the carboxyl group of polyamic acid into an ester, 4) substituting a part of the acid dianhydride contained in the tetracarboxylic dianhydride compound with an organic dicarboxylic acid and performing A polyamic acid-polyamide copolymer obtained by the reaction, and 5) a polyamideimide obtained by subjecting part or all of the polyamic acid-polyamide copolymer to a dehydration ring-closure reaction. Among these derivatives, for example, as a polyimide, a polyimide having a constituent unit represented by the formula (PI) can be cited, and as a polyamic acid ester, a polyimide having a structural unit represented by the following formula (PAE) can be mentioned. The constituent unit of polyamic acid ester.

In the formula (PAE), ^X1 is a tetravalent organic group, ^X2 is a divalent organic group, and Y is independently an alkyl group. For preferred ranges and specific examples of X ¹ and X ² , reference can be made to the description related to X ¹ and X ² in formula (PAA). Among Y, it is preferably a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group or tert-butyl group.

The polyamic acid can be obtained as a reaction product obtained by the polymerization reaction of tetracarboxylic dianhydrides and diamines. For the description, preferred range, and specific examples of tetracarboxylic dianhydrides, refer to the description in the column of tetracarboxylic dianhydrides below. For the description, preferred range, and specific examples of diamines, refer to the description in the column of the following diamines.

The tetracarboxylic dianhydrides and diamines used for the synthesis|combination of polyamic acid may each be 1 type, and may be 2 or more types. By using the compound represented by formula (1-1) or formula (1-2) as at least one of tetracarboxylic dianhydrides, and further using a photoreactive compound that imparts liquid crystal orientation to the alignment film through photoreaction. structure, the polyamic acid of the present invention can be obtained.

In the case where the polyamic acid of the present invention is a polyimide as a polyamic acid derivative, the obtained polyamic acid solution is mixed with acetic anhydride, propionic anhydride, trifluoroacetic anhydride as a dehydrating agent. Acid anhydrides such as acid anhydrides and tertiary amines such as triethylamine, pyridine, and collidine as dehydration ring-closing catalysts are subjected to imidization reaction at a temperature of 20°C to 150°C to obtain polyimide. Alternatively, polyamic acid can be precipitated from the obtained polyamic acid solution by using a large amount of poor solvents (alcoholic solvents such as methanol, ethanol, isopropanol or diol-based solvents), and the precipitated polyamic acid The imidization reaction is carried out at a temperature of 20° C. to 150° C. together with the dehydrating agent and the dehydration ring-closing catalyst in solvents such as toluene and xylene, thereby obtaining polyimide.

In the imidization reaction, the ratio of the dehydrating agent to the dehydrating ring-closing catalyst is preferably 0.1-10 (molar ratio). It is preferable that the total usage-amount of a dehydrating agent and a dehydration ring-closing catalyst is 1.5 times mole - 10 times mole with respect to the sum total of the molar quantity of the tetracarboxylic dianhydride used for the synthesis|combination of the said polyamic acid. By adjusting the dehydrating agent used in the imidation reaction, catalyst amount, reaction temperature and reaction time, the degree of imidation can be controlled, thus, only a part of the polyamic acid can be imidized and Part of the polyimide. The obtained polyimide can also be used as a liquid crystal aligning agent by separating from the solvent used for reaction, redissolving in another solvent, or using it as a liquid crystal aligning agent without separating from a solvent.

Polyamic acid esters can be obtained by the following methods: by reacting polyamic acid with hydroxyl-containing compounds, halides, epoxy-containing compounds, etc., or by making tetracarboxylic dianhydride-derived A method of synthesis by reacting carboxylic acid diester or tetracarboxylic acid diester dichloride with diamines. Tetracarboxylic acid diesters derived from tetracarboxylic dianhydrides can be obtained by reacting tetracarboxylic dianhydrides with 2 equivalents of alcohol and ring opening, and tetracarboxylic acid diester dichlorides can be obtained by making tetracarboxylic acid diesters and 2 Equivalent chlorination agent (for example, thionyl chloride, etc.) reaction to obtain. In addition, the polyamic acid ester may have only an amic acid ester structure, and may be a partial esterified product in which an amic acid structure and an amic acid ester structure coexist. By using the compound represented by formula (1-1) or formula (1-2) as at least one of tetracarboxylic dianhydrides, and further using a photoreactive compound that imparts liquid crystal orientation to the alignment film through photoreaction. The compound of structure can obtain the polyamic acid ester of the present invention.

The polyamic acid or its derivative of this invention can be manufactured similarly to the known polyamic acid or its derivative used for formation of a polyimide film. It is preferable that the total input amount of tetracarboxylic dianhydrides shall be 0.9 mol - 1.1 mol with respect to 1 mol of total diamines.

The liquid crystal aligning agent of this invention may contain only 1 type of the polyimide obtained by imidating these polyamic acid, a polyamic acid ester, and these, and may contain 2 or more types.

The molecular weight of the polyamic acid of this invention or its derivative is preferably 5,000-500,000, more preferably 5,000-50,000 in polystyrene conversion weight average molecular weight (Mw). The molecular weight of a polyamic acid or its derivative can be calculated|required by the measurement by the gel permeation chromatography (Gel Permeation Chromatography, GPC) method.

The polyamic acid of the present invention or derivative thereof can confirm its existence by following mode: Utilize infrared spectroscopy (Infrared spectroscopy, IR), nuclear magnetic resonance analysis (Nuclear Magnetic Resonance, NMR) to make polyamic acid of the present invention or The solid components obtained by precipitation of its derivatives in a large amount of poor solvent were analyzed. In addition, the monomers used can be confirmed by using gas chromatography (Gas Chromatography, GC), high performance liquid chromatography (High Performance Liquid Chromatography, HPLC) or gas chromatography-mass spectrometry (Gas Chromatography-Mass Spectrometry, GC -MS) Analysis of an extract extracted from the decomposed product using an organic solvent after decomposing the polyamic acid or its derivative using an aqueous solution of a strong base such as KOH or NaOH.

＜Other tetracarboxylic dianhydrides＞

Tetracarboxylic dianhydrides other than the compound represented by formula (1-1) or formula (1-2) used in the raw material of the polymer of the present invention can be selected from known tetracarboxylic dianhydrides without limitation. Class selection.

Hereinafter, examples of other tetracarboxylic dianhydrides are given. These tetracarboxylic dianhydrides can also be used as a raw material of a polymer by derivatizing them into tetracarboxylic-acid diester or tetracarboxylic-acid diester dichloride.

This kind of tetracarboxylic dianhydride can be an aromatic system (including a heteroaromatic ring system) in which a dicarboxylic anhydride is directly bonded to an aromatic ring and an aliphatic system (including a heteroaromatic ring system) in which a dicarboxylic anhydride is not directly bonded to an aromatic ring. Tetracarboxylic dianhydrides in any group of ring systems).

Examples of such tetracarboxylic dianhydrides include the following formulas (AN-1) to (AN-9), formula (AN-11), formula (AN-12), formula (AN-15), Compounds represented by formula (AN-10-1), formula (AN-10-2) and formula (AN-16-1) to formula (AN-16-15).

[Tetracarboxylic dianhydride represented by formula (AN-1)]

In formula (AN-1), G ¹¹ is a single bond, an alkylene group having 1 to 12 carbon atoms, a 1,4-phenylene group or a 1,4-cyclohexylene group. X ¹¹ is independently a single bond or -CH ₂ -. G ¹² is independently any of the following trivalent groups.

When G ¹² is >CH-, the hydrogen atom of >CH- may be substituted with a methyl group. When G ¹² is >N-, G ¹¹ is not a single bond and -CH ₂ -, and X ¹¹ is not a single bond.

R ¹¹ is independently a hydrogen atom or a methyl group.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-1), the compound represented by following formula (AN-1-1) - a formula (AN-1-15) is mentioned.

In formula (AN-1-2) and formula (AN-1-14), m is an integer of 1-12 each independently.

[Tetracarboxylic dianhydride represented by formula (AN-2)]

In formula (AN-2), R ⁶¹ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-2), the compound represented by following formula (AN-2-1) - a formula (AN-2-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-3)]

In formula (AN-3), ring A ¹¹ is a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-3), the compound represented by following formula (AN-3-1) and a formula (AN-3-2) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-4)]

In formula (AN-4), G ¹³ is a single bond, -(CH ₂ ) _m -, -O-, -S-, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, -C (CF ₃ ) ₂ -or a divalent group represented by the following formula (G13-1), m is an integer of 1-12. Ring A ¹¹ is each independently a cyclohexane ring or a benzene ring. G ¹³ can be bonded to any position of ring A ¹¹ .

In formula (G13-1), G ^13a and G ^13b are each independently a single bond, a divalent group represented by -O-, -CONH- or -NHCO-. The phenylene is preferably 1,4-phenylene or 1,3-phenylene.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-4), the compound represented by following formula (AN-4-1) - a formula (AN-4-31) is mentioned.

In formula (AN-4-17), m is an integer of 1-12.

[Tetracarboxylic dianhydride represented by formula (AN-5)]

In formula (AN-5), R ¹¹ is independently a hydrogen atom or a methyl group. R ¹¹ on the benzene ring among the two R ¹¹ is bonded to any one of positions that can be substituted on the benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-5), the compound represented by following formula (AN-5-1) - a formula (AN-5-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-6)]

In formula (AN-6), X ¹¹ is independently a single bond or -CH ₂ -. X ¹² is -CH ₂ -, -CH ₂ CH ₂ - or -CH═CH-. n is 1 or 2. When n is 2, the two X ¹² may be the same as or different from each other.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-6), the compound represented by following formula (AN-6-1) - a formula (AN-6-12) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-7)]

In formula (AN-7), X ¹¹ is a single bond or -CH ₂ -.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-7), the compound represented by following formula (AN-7-1) and a formula (AN-7-2) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-8)]

In formula (AN-8), X ¹¹ is a single bond or -CH ₂ -. R ¹² is a hydrogen atom, methyl, ethyl or phenyl. Ring ^A12 is a cyclohexane ring or a cyclohexene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-8), the compound represented by following formula (AN-8-1) and a formula (AN-8-2) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-9)]

In formula (AN-9), r is 0 or 1 each independently.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-9), the compound represented by following formula (AN-9-1) - a formula (AN-9-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-10-1) and formula (AN-10-2)]

[Tetracarboxylic dianhydride represented by formula (AN-11)]

In formula (AN-11), ring A ¹¹ is independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-11), the compound represented by following formula (AN-11-1) - a formula (AN-11-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-12)]

In formula (AN-12), ring A ¹¹ is each independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-12), the compound represented by following formula (AN-12-1) - a formula (AN-12-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-15)]

In formula (AN-15), w is an integer of 1-10.

As an example of the tetracarboxylic dianhydride represented by a formula (AN-15), the compound represented by following formula (AN-15-1) - a formula (AN-15-3) is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-16-1) to formula (AN-16-15)]

As tetracarboxylic dianhydride other than the above, the compound represented by following formula (AN-16-1) - a formula (AN-16-15) is mentioned.

Among the said tetracarboxylic dianhydrides, the suitable material which improves each characteristic of the liquid crystal aligning film mentioned later is demonstrated. In the case of emphasizing the further improvement of liquid crystal orientation, it is more preferred to be represented by formula (AN-1-2), formula (AN-4-17), formula (AN-4-21) or formula (AN-4-29). In the compound shown, m=4-8 is preferable in formula (AN-1-2), and m=4-8 is preferable in formula (AN-4-17).

In the case where emphasis is placed on improving the transmittance of the liquid crystal display element, formula (AN-1-1), formula (AN-1-2), formula (AN-2-1), formula (AN-3-1 ), Formula (AN-4-17), Formula (AN-4-30), Formula (AN-5-1), Formula (AN-7-2), Formula (AN-10-1), Formula (AN -16-3) or the compound represented by formula (AN-16-4), wherein, in formula (AN-1-2), preferably m=4 or 8, in formula (AN-4-17), preferably m=4-8, more preferably m=8.

When paying attention to improving the VHR of the liquid crystal display element, it is preferably formula (AN-1-1), formula (AN-1-2), formula (AN-3-1), formula (AN-4-17), Formula (AN-4-30), Formula (AN-7-2), Formula (AN-10-1), Formula (AN-16-3), Formula (AN-16-4) or Formula (AN-2 -1) In the compound represented by the formula (AN-1-2), m=4 or 8 is preferred, and in the formula (AN-4-17), m=4 or 8 is preferred, and m=8 is more preferred .

As one of the methods for preventing burn marks, it is effective to increase the relaxation speed of the residual charge (residual direct current (Direct Current, DC)) in the liquid crystal aligning film by reducing the volume resistance value of the liquid crystal aligning film. In the case of emphasizing the above purpose, it is preferably formula (AN-1-13), formula (AN-3-2), formula (AN-4-21), formula (AN-4-29) or formula (AN A compound represented by -11-3).

＜Other diamines＞

Diamines other than the compound represented by formula (2) or formula (3) used as a raw material of the polymer of the present invention can be selected from known diamines without limitation.

Diamines can be classified into two types according to their structures. That is, a diamine having a side chain group branched from the main chain when the skeleton connecting two amino groups is regarded as the main chain, and a diamine having no side chain group. In the following description, the diamine which has such a side chain group may be called a side chain type diamine. Moreover, the diamine which does not have such a side chain group may be called a non-side chain type diamine. The side chain group is a group having an effect of increasing the pretilt angle.

By appropriately using non-side chain type diamine and side chain type diamine separately, it can correspond to each desired pretilt angle.

It is preferable to use side chain type diamine together to the extent that the characteristic of this invention is not impaired. Moreover, it is preferable to select and use side chain type diamine and non-side chain type diamine for the purpose of improving characteristics, such as the vertical alignment property with respect to a liquid crystal, VHR, and afterimage characteristics.

The known diamine which does not have a side chain is shown by following formula (DI-1) - a formula (DI-16).

In the formula (DI-1), G ²⁰ is -CH ₂ - or a group represented by the formula (DI-1-a). When G ²⁰ is -CH ₂ -, at least one of the m -CH ₂ -s may be substituted with -NH- or -O-, and at least one hydrogen atom of the m -CH ₂ -s may be substituted with a hydroxyl group or a methyl group. m is an integer of 1-12. When m in DI-1 is 2 or more, a plurality of G ²⁰ may be the same as or different from each other. Wherein, when ^G20 is formula (DI-1-a), m is 1.

In formula (DI-1-a), v is an integer of 1-6 each independently.

In formula (DI-3), formula (DI-6) and formula (DI-7), G ²¹ is independently a single bond, -NH-, -NCH ₃ -, -O-, -S-, -SS- , -SO ₂ -, -CO-, -COO-, -CONCH ₃ -, -CONH-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -(CH ₂ ) _m -, - O-(CH ₂ ) _m -O-, -N(CH ₃ )-(CH ₂ ) _k -N(CH ₃ )-, -(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C (CF ₃ ) ₂ -CH ₂ -O-, -O-CO-(CH ₂ ) _m -CO-O-, -CO-O-(CH ₂ ) _m -O-CO-, -(CH ₂ ) _m -NH-(CH ₂ ) _m -, -CO-(CH ₂ ) _k -NH-(CH ₂ ) _k -, -(NH-(CH ₂ ) _m ) _k -NH-, -CO-C ₃ H ₆ -(NH-C ₃ H ₆ ) _n -CO- or -S-(CH ₂ ) _m -S-, m is independently an integer of 1-12, k is an integer of 1-5, and n is 1 or 2.

In formula (DI-4), s is an integer of 0-2 independently.

In formula (DI-5), G ³³ is a single bond, -NH-, -NCH ₃ -, -O-, -S-, -SS-, -SO ₂ -, -CO-, -COO-, -CONCH ₃ -, -CONH-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -(CH ₂ ) _m -, -O-(CH ₂ ) _m -O-, -N(CH ₃ )-(CH ₂ ) _k -N(CH ₃ )-, -(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C(CF ₃ ) ₂ -CH ₂ -O-, -O-CO -(CH ₂ ) _m -CO-O-, -CO-O-(CH ₂ ) _m -O-CO-, -(CH ₂ ) _m -NH-(CH ₂ ) _m -, -CO-(CH ₂ ) _k -NH-(CH ₂ ) _k -, -(NH-(CH ₂ ) _m ) _k -NH-, -CO-C ₃ H ₆ -(NH-C ₃ H ₆ ) _n -CO- or -S -(CH ₂ ) _m -S-, -N(Boc)-(CH ₂ ) _e -N(Boc)-, -NH-(CH ₂ ) _e -N(Boc)-, -N(Boc)-( CH ₂ ) _e -, -(CH ₂ ) _m -N(Boc)-CONH-(CH ₂ ) _m -, -(CH ₂ ) _m -N(Boc)-(CH ₂ ) _m -, or the following formula (DI-5-a) or the group represented by the following formula (DI-5-b), m is independently an integer of 1 to 12, k is an integer of 1 to 5, e is an integer of 2 to 10, n is 1 or 2. Boc is t-butoxycarbonyl.

In formula (DI-6) and formula (DI-7), G ²² is independently a single bond, -O-, -S-, -CO-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - or an alkylene group having 1 to 10 carbon atoms.

At least one hydrogen atom of the cyclohexane ring and benzene ring in formula (DI-2) to formula (DI-7) can be replaced by a fluorine atom, a chlorine atom, an alkylene group with 1 to 3 carbons, a methoxyl group, a hydroxyl group , trifluoromethyl, carboxyl, carbamoyl, phenylamino, phenyl or benzyl substitution, in addition, in formula (DI-4), at least one hydrogen atom of cyclohexane ring and benzene ring can be selected One of the groups represented by any one of the following formula (DI-4-a) to formula (DI-4-i) is substituted, and in formula (DI-5), G ³³ is a single bond , at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted by NHBoc or N(Boc) ₂ .

The group whose bonding position is not fixed to the carbon atom constituting the ring means that the bonding position on the ring is arbitrary. Furthermore, the bonding position of the amino group on the cyclohexane ring or the benzene ring is any position other than the bonding position of G ²¹ , G ²² or G ³³ .

In formula (DI-4-a) and formula (DI-4-b), R ²⁰ is independently a hydrogen atom or a methyl group. In formula (DI-4-f) and formula (DI-4-g), m is each independently an integer of 0 to 12, and Boc is a tert-butoxycarbonyl group.

In formula (DI-5-a), q is an integer of 0-6 each independently. R ⁴⁴ is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbons, or an alkoxy group having 1 to 6 carbons.

In formula (DI-11), r is 0 or 1. In formulas (DI-8) to (DI-11), the bonding position of the amino group bonded to the ring is any position.

In the formula (DI-12), R ²¹ and R ²² are independently an alkyl group or phenyl group having 1 to 3 carbons, and G ²³ is independently an alkylene group, phenylene group or alkylene group having 1 to 6 carbons. A phenylene group substituted with a group, w is an integer of 1-10.

In formula (DI-13), ^R23 is independently an alkyl group with 1 to 5 carbons, an alkoxy group with 1 to 5 carbons, or -Cl, p is independently an integer of 0 to 3, and q is 0 to 4 an integer of .

In formula (DI-14), ring B is a monocyclic heterocyclic aromatic group, and ^R24 is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group with 1 to 6 carbon atoms, an alkoxy group, an alkenyl group or an alkyne group base, q is an integer of 0-4 independently. When q is 2 or more, a plurality of R ²⁴ may be the same as or different from each other.

In formula (DI-15), ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group.

In formula (DI-16), G ²⁴ is a single bond, an alkylene group having 2 to 6 carbon atoms, or 1,4-phenylene group, and r is 0 or 1. Furthermore, a group whose bonding position is not fixed to a carbon atom constituting the ring means that the bonding position on the ring is arbitrary. In the formula (DI-13) to the formula (DI-16), the bonding position of the amino group bonded to the ring is an arbitrary position.

The example of the diamine represented by a formula (DI-1) is shown in following formula (DI-1-1) - a formula (DI-1-9).

In formula (DI-1-7) and formula (DI-1-8), k is an integer of 1-3 each independently. In formula (DI-1-9), v is an integer of 1-6 each independently.

In the following formula (DI-2-1), formula (DI-2-2), formula (DI-3-1) to formula (DI-3-3), formula (DI-2) to formula (DI -3) Examples of diamines represented.

The example of the diamine represented by a formula (DI-4) is shown in following formula (DI-4-1) - a formula (DI-4-27).

In formula (DI-4-20) and formula (DI-4-21), m is an integer of 1-12 each independently.

The example of the diamine represented by a formula (DI-5) is shown in following formula (DI-5-1) - a formula (DI-5-50).

In formula (DI-5-1), m is an integer of 1-12.

In formula (DI-5-12) and formula (DI-5-13), m is an integer of 1-12 each independently.

In formula (DI-5-16), v is an integer of 1-6.

In formula (DI-5-30), k is an integer of 1-5.

In formula (DI-5-35) ~ formula (DI-5-37) and formula (DI-5-39), m is independently an integer of 1 to 12, formula (DI-5-38) and formula ( In DI-5-39), k is each independently an integer of 1-5, and in formula (DI-5-40), n is an integer of 1 or 2.

In formulas (DI-5-42) to formulas (DI-5-44), e is independently an integer of 2 to 10, and in formula (DI-5-45), R ⁴³ is a hydrogen atom, (tert-butoxy ylcarbonyl)amino or bis(tert-butoxycarbonyl)amino. In formulas (DI-5-42) to (DI-5-44), Boc is tert-butoxycarbonyl.

The example of the diamine represented by a formula (DI-6) is shown in following formula (DI-6-1) - a formula (DI-6-7).

The example of the diamine represented by a formula (DI-7) is shown in following formula (DI-7-1) - a formula (DI-7-11).

In formula (DI-7-3) and formula (DI-7-4), m is an integer of 1-12 each independently, and n is 1 or 2 independently.

The example of the diamine represented by a formula (DI-8) is shown in following formula (DI-8-1) - a formula (DI-8-4).

The example of the diamine represented by a formula (DI-9) is shown in following formula (DI-9-1) - a formula (DI-9-3).

The example of the diamine represented by a formula (DI-10) is shown in following formula (DI-10-1) and a formula (DI-10-2).

The example of the diamine represented by a formula (DI-11) is shown in following formula (DI-11-1) - a formula (DI-11-3).

The example of the diamine represented by a formula (DI-12) is shown in following formula (DI-12-1).

The example of the diamine represented by a formula (DI-13) is shown in following formula (DI-13-1) - a formula (DI-13-13).

The example of the diamine represented by a formula (DI-14) is shown in following formula (DI-14-1) - a formula (DI-14-9).

The example of the diamine represented by a formula (DI-15) is shown in following formula (DI-15-1) - a formula (DI-15-12).

The example of the diamine represented by a formula (DI-16) is shown in following formula (DI-16-1).

Next, the dihydrazide used as the raw material of the polymer of this invention is demonstrated. As a known dihydrazide which does not have a side chain, the compound represented by any one of following formula (DIH-1) - a formula (DIH-3) is mentioned.

In formula (DIH-1), G ²⁵ is a single bond, an alkylene group having 1 to 20 carbons, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -.

In the formula (DIH-2), the ring D is a cyclohexane ring, a benzene ring or a naphthalene ring, and at least one hydrogen atom of said group may be substituted by a methyl group, an ethyl group or a phenyl group.

In the formula (DIH-3), the ring E is independently a cyclohexane ring or a benzene ring, and at least one hydrogen atom of the above group may be substituted by a methyl group, an ethyl group or a phenyl group. A plurality of rings E may be the same as or different from each other. Y is a single bond, an alkylene group having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -.

In formula (DIH-2) and formula (DIH-3), the bonding position of the hydrazide group bonded to the ring is an arbitrary position.

In the following formula (DIH-1-1), formula (DIH-1-2), formula (DIH-2-1) ~ formula (DIH-2-3), formula (DIH-3-1) ~ formula ( DIH-3-6) shows an example of the compound represented by any one of formula (DIH-1) to formula (DIH-3).

In formula (DIH-1-2), m is an integer of 1-12.

Diamines suitable for the purpose of increasing the pretilt angle will be described. Although the compound of this invention can be used suitably for the liquid crystal aligning agent used for a transverse electric field type liquid crystal display element, it can also use together with diamine as follows to increase a pretilt angle. As diamines suitable for the purpose of increasing the pretilt angle and having side chain groups, formula (DI-31) to formula (DI-35) and formula (DI-36-1) to formula (DI-36-8 ) any one of the diamines represented.

In formula (DI-31), G ²⁶ is a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O- , -OCF ₂ - or -(CH ₂ ) _ma -, ma is an integer of 1-12. Preferable examples of ^G26 are single bond, -O-, -COO-, -OCO-, _-CH2O- , and an alkylene group having 1 to 3 carbon atoms, and particularly preferred examples are single bond, -O-, - COO-, -OCO-, -CH ₂ O-, -CH ₂ - and -CH ₂ CH ₂ -. R ²⁵ is an alkyl group having 3 to 30 carbon atoms, a phenyl group, a group having a steroid skeleton, or a group represented by the following formula (DI-31-a). In the alkyl group, at least one hydrogen atom may be substituted by a fluorine atom, and at least one -CH ₂ - may be substituted by -O-, -CH═CH- or -C≡C-. The hydrogen atom of the phenyl group can be fluorine atom, methyl group, methoxyl group, fluoromethyloxyl group, difluoromethyloxyl group, trifluoromethyloxyl group, an alkyl group with 3 to 30 carbon atoms or an alkyl group with 3 to 30 carbon atoms. 3 to 30 alkoxy substitutions. The bonding position of the amino group bonded to the benzene ring means any position on the ring, and the bonding position is preferably meta-position or para-position. That is, when the bonding position of the group "R ²⁵ -G ²⁶ -" is assumed to be 1, the two bonding positions are preferably 3 and 5 or 2 and 5.

In the formula (DI-31-a), G ²⁷ , G ²⁸ and G ²⁹ are bonding groups, which are each independently a single bond or an alkylene group with 1 to 12 carbons, and one or more of the alkylene groups -CH ₂ - may be substituted by -O-, -COO-, -OCO-, -CONH- or -CH═CH-. Ring B ²¹ , Ring B ²² , Ring B ²³ and Ring B ²⁴ are each independently 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, Pyrimidine-2,5-diyl, pyridine-2,5-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9,10-diyl, ring B ²¹ , ring In B ²² , ring B ²³ , and ring B ²⁴ , at least one hydrogen atom may be substituted by a fluorine atom or a methyl group, s, t, and u are each independently an integer from 0 to 2, and the total of them is 1 to 5. In s When , t or u is 2, the two bonding groups in each bracket may be the same or different, and the two rings may be the same or different. ^R26 is a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group with 1 to 30 carbons, a fluorine-substituted alkyl group with 1 to 30 carbons, an alkoxy group with 1 to 30 carbons, a cyano group, a fluoromethyloxy group, Difluoromethyloxy or trifluoromethyloxy, at least one -CH ₂ - of the alkyl group having 1 to 30 carbons may be substituted by a divalent group represented by the following formula (DI-31-b) .

In formula (DI-31-b), R ²⁷ and R ²⁸ are each independently an alkyl group having 1 to 3 carbons, and v is an integer of 1 to 6. Preferred examples of R ²⁶ are alkyl having 1 to 30 carbons and alkoxy having 1 to 30 carbons.

In formula (DI-32) and formula (DI-33), G ³⁰ is independently a single bond, -CO- or -CH ₂ -, R ²⁹ is independently a hydrogen atom or a methyl group, R ³⁰ is a hydrogen atom, carbon An alkyl group having 1 to 20 carbons or an alkenyl group having 2 to 20 carbons. At least one hydrogen atom of the benzene ring in formula (DI-33) may be substituted with an alkyl group or phenyl group having 1 to 20 carbon atoms. Furthermore, a group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary. Preferably, one of the two groups "-phenylene-G ³⁰ -O-" in the formula (DI-32) is bonded to the 3-position of the steroid core, and the other is bonded to the 6-position of the steroid core. The bonding positions of the two groups "-phenylene-G ³⁰ -O-" in the formula (DI-33) on the benzene ring are preferably meta- or para-positions relative to the steroid core. In formula (DI-32) and formula (DI-33), the amino group bonded to the benzene ring means that the bonding position on the ring is arbitrary.

In formula (DI-34) and formula (DI-35), G ³¹ is independently -O- or an alkylene group having 1 to 6 carbons, and G ³² is a single bond or an alkylene group having 1 to 3 carbons. R ³¹ is a hydrogen atom or an alkyl group having 1 to 20 carbons, at least one -CH ₂ - of the alkyl group may be substituted by -O-, -CH═CH- or -C≡C-. R ³² is an alkyl group with 6 to 22 carbons, and R ³³ is a hydrogen atom or an alkyl group with 1 to 22 carbons. Ring B ²⁵ is 1,4-phenylene or 1,4-cyclohexylene, and r is 0 or 1. Furthermore, the amino group bonded to the benzene ring means that the bonding position on the ring is arbitrary, and is preferably meta-position or para-position independently of the bonding position of ^G31 .

Examples of the compound represented by the formula (DI-31) are shown in the following formula (DI-31-1) to formula (DI-31-55).

In formulas (DI-31-1) to formulas (DI-31-11), R ³⁴ are each independently an alkyl group with 1 to 30 carbons or an alkoxy group with 1 to 30 carbons, preferably 5 to 30 carbons. 25 alkyl or alkoxy having 5 to 25 carbons. R ³⁵ are each independently an alkyl group having 1 to 30 carbons or an alkoxy group having 1 to 30 carbons, preferably an alkyl group having 3 to 25 carbons or an alkoxy group having 3 to 25 carbons.

In formula (DI-31-12) to formula (DI-31-17), R ³⁶ is each independently an alkyl group having 4 to 30 carbons, preferably an alkyl group having 6 to 25 carbons. R ³⁷ are each independently an alkyl group having 6 to 30 carbons, preferably an alkyl group having 8 to 25 carbons.

In formulas (DI-31-18) to formulas (DI-31-43), R ³⁸ are each independently an alkyl group with 1 to 20 carbons or an alkoxy group with 1 to 20 carbons, preferably 3 to 20 carbons. An alkyl group with 20 carbon atoms or an alkoxy group with 3 to 20 carbon atoms. ^R39 are each independently a hydrogen atom, a fluorine atom, an alkyl group with 1 to 30 carbons, an alkoxy group with 1 to 30 carbons, a cyano group, a fluoromethyloxy group, a difluoromethyloxy group or a trifluoromethyl group The oxy group is preferably an alkyl group having 3 to 25 carbons or an alkoxy group having 3 to 25 carbons. Furthermore, ^G33 is an alkylene group having 1 to 20 carbon atoms.

Examples of the compound represented by the formula (DI-32) are shown in the following formula (DI-32-1) to formula (DI-32-4).

Examples of the compound represented by the formula (DI-33) are shown in the following formula (DI-33-1) to formula (DI-33-8).

Examples of the compound represented by the formula (DI-34) are shown in the following formula (DI-34-1) to formula (DI-34-12).

In formula (DI-34-1) to formula (DI-34-12), R ⁴⁰ is each independently a hydrogen atom or an alkyl group with 1 to 20 carbons, preferably a hydrogen atom or an alkyl group with 1 to 10 carbons , and, R ⁴¹ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbons.

Examples of the compound represented by the formula (DI-35) are shown in the following formula (DI-35-1) to formula (DI-35-3).

In the formulas (DI-35-1) to (DI-35-3), R ³⁷ are each independently an alkyl group with 6 to 30 carbons, and R ⁴¹ are each independently a hydrogen atom or an alkane with 1 to 12 carbons. base.

Compounds represented by formula (DI-36-1) to formula (DI-36-8) are shown below.

In formula (DI-36-1) to formula (DI-36-8), R ⁴² is each independently an alkyl group having 3 to 30 carbon atoms.

Among the above-mentioned diamines, suitable materials for improving each characteristic of the liquid crystal aligning film described later will be described. When emphasizing the improvement of liquid crystal orientation, it is preferable to use formula (DI-1-3), formula (DI-5-1), formula (DI-5-5), formula (DI-5-9), formula (DI-5-12), formula (DI-5-13), formula (DI-5-29), formula (DI-6-7), formula (DI-7-3) or formula (DI-11- 2) Compounds represented. In formula (DI-5-1), m=2-8 is preferable, and m=4-8 is more preferable. In formula (DI-5-12), m=2-6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable.

In the case of emphasizing the improvement of transmittance, it is preferable to use formula (DI-1-3), formula (DI-2-1), formula (DI-5-1), formula (DI-5-5), formula (DI-5-24) or the diamine represented by formula (DI-7-3), More preferably, it is a compound represented by formula (DI-2-1). In formula (DI-5-1), m=2-8 is preferable, and m=8 is more preferable. In formula (DI-7-3), m=2 or 3 and n=1 or 2 are preferable, and m=3 and n=1 are more preferable.

When it is important to improve the VHR of the liquid crystal display element, it is preferable to use formula (DI-2-1), formula (DI-4-1), formula (DI-4-2), formula (DI-4-10) , formula (DI-4-15), formula (DI-4-22), formula (DI-5-1), formula (DI-5-28), formula (DI-5-30) or formula (DI- The compound represented by 13-1) is more preferably a diamine represented by formula (DI-2-1), formula (DI-5-1) or formula (DI-13-1). In formula (DI-5-1), m=1 is preferable. In the formula (DI-5-30), k=2 is preferable.

As one of the methods for preventing burn marks, it is effective to increase the relaxation speed of the residual electric charge (residual DC) in the liquid crystal aligning film by reducing the volume resistance value of the liquid crystal aligning film. When emphasizing the above purpose, it is preferable to use formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-15), formula ( DI-5-1), formula (DI-5-12), formula (DI-5-13), formula (DI-5-28), formula (DI-4-20), formula (DI-4-21 ), formula (DI-7-12) or the compound represented by formula (DI-16-1), more preferably formula (DI-4-1), formula (DI-5-1) or formula (DI-5 A compound represented by -13). In formula (DI-5-1), m=2-8 is preferable, and m=4-8 is more preferable. In formula (DI-5-12), m=2-6 is preferable, and m=5 is more preferable. In the formula (DI-5-13), m=1 or 2 is preferable, and m=1 is more preferable. In the formula (DI-7-12), m=3 or 4 is preferable, and m=4 is more preferable.

In the raw material composition used as a raw material of the polymer of the present invention, a part of diamines may be substituted with at least one selected from the group consisting of monoamines and monohydrazides. Regarding the ratio of substitution, it is preferable that the ratio of at least one selected from the group consisting of monoamines and monohydrazides with respect to diamines is in a range of 40 mol % or less. Such substitution can cause the termination of the polymerization reaction at the time of producing the polyamic acid, and can inhibit the further progress of the polymerization reaction. Therefore, by such substitution, the molecular weight of the polymer (polyamic acid or its derivative) obtained can be controlled easily, for example, the coating characteristic of a liquid crystal aligning agent can be improved, without impairing the effect of this invention. As long as the effects of the present invention are not impaired, the diamines which may be substituted with a monoamine or a monohydrazide may be one kind or two or more kinds. Examples of the monoamine include: aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-decylamine, Monoamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, p-aminophenyltrimethoxy Silane and 3-Aminopropyltriethoxysilane.

When the polymer of the present invention is a polyamic acid or a derivative thereof, the raw material composition may further contain a monoisocyanate compound as a monomer. By including a monoisocyanate compound as a monomer, the terminal of the obtained polyamic acid or its derivative is modified, and molecular weight is adjusted. By using the polyamic acid of the said terminal modification type or its derivative(s), the application|coating characteristic of a liquid crystal aligning agent can be improved, for example without impairing the effect of this invention. It is preferable that content of the monoisocyanate compound in a monomer is 1 mol% - 10 mol% with respect to the total amount of the diamine in a monomer, and tetracarboxylic dianhydride from the said viewpoint. As said monoisocyanate compound, a phenyl isocyanate and a naphthyl isocyanate are mentioned, for example.

The liquid crystal aligning agent of this invention may contain one kind of polymer of this invention, and may mix the polymer of this invention and polymers other than this invention. In addition, in this specification, the liquid crystal aligning agent containing 1 type of said polymer may be called a single-layer type liquid crystal aligning agent. The liquid crystal aligning agent which mixed the said polymer of 2 or more types may be called a blend type liquid crystal aligning agent. The blend type liquid crystal aligning agent is especially used when VHR reliability or other electrical characteristics are important.

As polymers other than this invention used for a blend type liquid crystal aligning agent, any one or more of a polyamic acid and a polyamic acid derivative is preferable. As polymers other than the present invention, with regard to polyamic acid and polyamic acid derivatives, except that the compound having a photoreactive structure and the compound represented by formula (1-1) or formula (1-2) are included as the raw material composition Except for the compounds shown, the description of the polymer of the present invention can be referred to.

In the case of using two-component polymers, for example, there are the following forms: one of them is selected from a polymer having excellent performance in liquid crystal alignment ability, and the other is selected from a polymer having excellent properties for improving the electrical characteristics of a liquid crystal display element. A polymer having excellent performance is suitable for obtaining an alignment agent having a good balance between liquid crystal alignment and electrical properties.

In such a case, by controlling the structure and molecular weight of each polymer, it is possible to apply a liquid crystal aligning agent obtained by dissolving these polymers in a solvent on a substrate and pre-dry them to form a thin film as described later. In the process, a polymer excellent in liquid crystal alignment ability is segregated in the upper layer of the film, and a polymer excellent in improving electrical characteristics of a liquid crystal display element is segregated in the lower layer of the film. Among the polymers present in a mixture, a phenomenon that a polymer with a small surface energy is separated into an upper layer and a polymer with a large surface energy is separated into a lower layer can be used. Confirmation of such layer separation can be confirmed by confirming that the surface energy of the formed liquid crystal aligning film is the same as or a value close to the surface energy of a film formed of a liquid crystal aligning agent containing only a polymer intended to segregate in the upper layer. .

As a method for developing layer separation, reducing the molecular weight of the polymer to be segregated in the upper layer is also mentioned.

In the liquid crystal aligning agent containing the mixture of polymers, layer separation can also be expressed by making the polymer which is going to segregate in an upper layer a polyimide.

The compound represented by formula (1-1) or formula (1-2) can be used as the raw material of the polymer segregated in the upper layer of the film, and can also be used as the raw material of the polymer segregated in the lower layer of the film. In addition, It can also be used as a raw material for two types of polymers, more preferably as a raw material for a polymer segregated in the upper layer of the film.

The compound represented by formula (2) or formula (3) can be used as the raw material of the polymer segregated in the upper layer of the film, and can also be used as the raw material of the polymer segregated in the lower layer of the film. In addition, it can also be used as The raw materials of the two kinds of polymers are more preferably used as the raw materials of the polymers segregated in the upper layer of the film.

Formula (1-1) or formula (1-2) for synthesizing the polyamic acid or its derivatives segregated in the upper layer of the film and the polyamic acid or its derivatives segregated in the lower layer of the film Tetracarboxylic dianhydrides other than the compounds shown can be selected from the known tetracarboxylic dianhydrides exemplified above without limitation.

Tetracarboxylic dianhydride used to synthesize polyamic acid or derivatives thereof segregated in the upper layer of the film is preferably formula (AN-1-1), formula (AN-1-2), formula (AN-2-1) , the compound represented by formula (AN-3-1), formula (AN-4-5), formula (AN-4-17) or formula (AN-4-21), more preferably formula (AN-4- 17) or formula (AN-4-21). In formula (AN-4-17), m=4-8 is preferable.

As the tetracarboxylic dianhydride used to synthesize polyamic acid or derivatives thereof segregated in the lower layer of the film, it is preferably formula (AN-1-1), formula (AN-1-13), formula (AN-2- 1), the compound represented by formula (AN-3-2) or formula (AN-4-21), more preferably formula (AN-1-1), formula (AN-2-1) or formula (AN- 3-2).

Tetracarboxylic dianhydride used to synthesize polyamic acid or its derivatives segregated in the lower layer of the film preferably contains 10 mol% or more of aromatic tetracarboxylic dianhydride in the total amount of tetracarboxylic dianhydride, more preferably To contain 30 mol% or more.

As diamines other than compounds represented by formula (2) used to synthesize polyamic acid or its derivatives segregated in the upper layer of the film and polyamic acid or its derivatives segregated in the lower layer of the film, there may be no It is limitedly selected from the exemplified known diamines.

As diamines for synthesizing polyamic acid or derivatives thereof segregated on the upper layer of the film, it is preferable to use formula (DI-4-1), formula (DI-4-13), formula (DI-4-15 ), the compound represented by formula (DI-5-1), formula (DI-7-3) or formula (DI-13-1). Among them, it is more preferable to use a compound represented by formula (DI-4-13), formula (DI-4-15), formula (DI-5-1) or formula (DI-13-1). In formula (DI-5-1), m=4-8 is preferable. In formula (DI-7-3), m=3 and n=1 are preferable.

As diamines for synthesizing polyamic acid or its derivatives segregated in the lower layer of the film, formula (DI-4-1), formula (DI-4-2), formula (DI-4-10) are preferable , Formula (DI-4-18), Formula (DI-4-19), Formula (DI-5-1), Formula (DI-5-9), Formula (DI-5-28), Formula (DI- 5-30), a compound represented by formula (DI-13-1) or formula (DIH-1-2). In formula (DI-5-1), a compound with m=1 or 2 is preferable, and in formula (DI-5-30), a compound with k=2 is preferable. Among them, more preferably formula (DI-4-1), formula (DI-4-18), formula (DI-4-19), formula (DI-5-9), formula (DI-13-1) or A compound represented by the formula (DIH-1-2).

The diamines used to synthesize the polyamic acid or its derivatives segregated in the lower layer of the film preferably contain 30 mol% or more of the diamines selected from aromatic diamines and aromatic dihydrazides relative to all diamines. At least one of the groups is more preferably contained in an amount of 50 mol % or more.

As the ratio of the polyamic acid or its derivatives segregated in the upper layer of the film to the total amount of the polyamic acid or its derivatives segregated in the upper layer of the film and the polyamic acid or its derivatives segregated in the lower layer of the film, preferably It is 5 weight% - 60 weight%, More preferably, it is 20 weight% - 50 weight%.

The polyamic acid or derivative thereof of the present invention may be a block polymer including a first polymer chain and a second polymer chain having a structure different from that of the first polymer chain. In addition, the block polymer may further include another polymer chain having a structure different from that of the first polymer chain and the second polymer chain. For example, the block polymer of polyamic acid can be by the solution of the specific polyamic acid (PAA1) represented by formula (PAA) and the combination of ^X1 and ^X2 and polyamic acid (PAA1) different polyamic acid ( Solutions of PAA2) were mixed and heated to form. The block polymer of the polyamic acid formed in this way contains the block represented by (PAA1) _n1 , and the block represented by (PAA2) _n2 . _n1 and _n2 in (PAA1) n1 and (PAA2) n2 are each independently an integer of 1 or more, preferably an integer of 2 or more each independently. In the block polymer, the compound represented by formula (1-1) or formula (1-2) and formula (2) or formula (3) can be used as the polymer chain of the raw material composition, either, or Two or more polymer chains may be used, or all polymer chains may be used.

Here, after producing two or more types of polyamic acids individually, a polyamic-acid block polymer can mix and heat it, and can synthesize|combine them. Or it is also possible to synthesize more than two kinds of polyamic acids in the same reaction vessel as after synthesizing the first polyamic acid, and then carry out Heated to synthesize.

In the case of producing a block polymer, in the raw material composition used as the raw material of the polymer of the present invention, the formula (1-1) or the formula (1 The compound represented by -2) is preferably 10 mol% or more, more preferably 20 mol% or more. The compound represented by formula (2) or formula (3) is preferably 10 mol % or more with respect to the total amount of diamines used as a raw material, and is more preferably 20 mol % or more.

Moreover, the liquid crystal aligning agent of this invention may contain a solvent further from the viewpoint of the coating property of a liquid crystal aligning agent, or the adjustment of the density|concentration of the said polyamic acid or its derivative(s). The solvent can be used without particular limitation as long as it has the ability to dissolve the polymer component. The solvent widely includes those commonly used in the production process and application of polymer components such as polyamic acid and soluble polyimide, and can be appropriately selected according to the purpose of use. The solvent may be one kind, or a mixture of two or more solvents.

As a solvent, the said polyamic acid or its derivative(s) is a solvophile, and other solvents for the purpose of improving applicability are mentioned.

Examples of aprotic polar organic solvents that are solvent-friendly to polyamic acid or derivatives thereof include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and dimethylimidazolidone , N-methylcaprolactam, N-methylpropionamide, N,N-dimethylacetamide, dimethylsulfoxide, N,N-dimethylformamide, N,N-diethylformamide, Diethylacetamide, N,N-dimethylisobutylamide, γ-butyrolactone and γ-valerolactone, etc. Among these solvents, N-methyl-2-pyrrolidone, dimethylimidazolidinone, γ-butyrolactone, or γ-valerolactone are preferred.

Examples of other solvents for the purpose of improving coatability, etc. include ethylene glycol monoalkyl ethers such as ethylene glycol monobutyl ether and ethylene glycol mono-tert-butyl ether, and diethylene glycol monoethyl ether and other solvents. Diethylene glycol dialkyl ethers such as ethylene glycol monoalkyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, and diethylene glycol butyl methyl ether. In addition, propylene glycol monomethyl ether, propylene glycol monoalkyl ethers such as 1-butoxy-2-propanol, dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether, triethylene glycol monoalkyl ether, butyl solvent, etc. Cellulose acetate, phenyl acetate and ester compounds such as these acetates. Further, dialkyl malonate such as diethyl malonate, alkyl lactate, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4- Methyl-2-pentanol, diisobutylcarbinol, tetralin and isophorone.

Among these solvents, diisobutyl ketone, 4-methyl-2-pentanol, diisobutyl methanol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol monoethyl ether , diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy-2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether or butyl cellosolve agent acetate.

The solid content concentration in the liquid crystal aligning agent of this invention is not specifically limited, What is necessary is just to select the most suitable value in combination with the following various coating methods. Usually, in order to suppress unevenness and pinholes during coating, it is preferably 0.1% by weight to 30% by weight, more preferably 1% by weight to 10% by weight, based on the weight of the varnish.

The viscosity of the liquid crystal aligning agent of the present invention differs in the preferred range depending on the coating method, the concentration of polyamic acid or its derivative, the kind of polyamic acid or its derivative used, and the kind and ratio of the solvent. For example, in the case of applying with a printing machine, it is 5 mPa·s to 100 mPa·s (more preferably 10 mPa·s to 80 mPa·s). If it is 5 mPa·s or more, it will be easy to obtain a sufficient film thickness, and if it is 100 mPa·s or less, it will be easy to suppress printing unevenness. In the case of coating by spin coating, it is suitable to be 5 mPa·s to 200 mPa·s (more preferably 10 mPa·s to 100 mPa·s). When coating is performed using an inkjet coating device, it is suitable to be 5 mPa·s to 50 mPa·s (more preferably 5 mPa·s to 20 mPa·s). The viscosity of a liquid crystal aligning agent can be measured by the rotational viscometry method, For example, it can measure using the rotational viscometer (TVE-20L type by Toki Sangyo make) (measurement temperature: 25 degreeC).

The liquid crystal aligning agent of this invention may contain various additives further. In order to improve various characteristics of the alignment film, various additives can be selected and used according to various purposes. Examples are shown below.

＜Alkenyl Substituted Nadicimide Compound＞

For example, the liquid crystal aligning agent of the present invention may further contain an alkenyl-substituted nadicimide compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. One type of alkenyl-substituted nadicimide compound may be used, or two or more types may be used in combination. For the purpose, the content of the alkenyl-substituted nadicimide compound is preferably 1% by weight to 50% by weight, more preferably 1% by weight to 30% by weight relative to the polyamic acid or its derivatives, and further Preferably it is 1% by weight to 20% by weight. The alkenyl-substituted nadicimide compound is preferably a compound soluble in a solvent in which the polyamic acid or its derivative used in the present invention is dissolved. Preferred alkenyl-substituted nadicimide compounds can be listed in JP-A-2008-096979, JP-A-2009-109987, and JP-A-2013-242526. Dictimide compounds. As a particularly preferable alkenyl-substituted nadicimide compound, bis{4-(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide)phenyl} Methane, N,N'-m-xylylene-bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide) or N,N'-hexamethylene - bis(allylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide).

<Compounds having radically polymerizable unsaturated double bonds>

For example, the liquid crystal aligning agent of this invention may contain the compound which has a radically polymerizable unsaturated double bond further for the purpose of stabilizing the electric characteristic of a liquid crystal display element for a long period of time. The compound having a radically polymerizable unsaturated double bond may be one kind of compound, or two or more kinds of compounds. In addition, no alkenyl-substituted nadicimide compound is included in the compound having a radically polymerizable unsaturated double bond. Among compounds having a radically polymerizable unsaturated double bond, preferred compounds include: N,N'-methylenebisacrylamide, N,N'-dihydroxyethylene-bisacrylamide, Ethyl diacrylate, 4,4'-methylene bis(N,N-dihydroxyethylene acrylate aniline), triallyl cyanurate; and Japanese Patent Laid-Open No. 2009-109987, Japan Compounds having radically polymerizable unsaturated double bonds disclosed in Japanese Patent Laid-Open No. 2013-242526, International Publication No. 2014/119682, and International Publication No. 2015/152014. For the purpose, the content of the compound having a radically polymerizable unsaturated double bond is preferably 1% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, based on the polyamic acid or its derivatives. .

＜Oxazine compounds＞

For example, the liquid crystal aligning agent of this invention may contain an oxazine compound further for the purpose of stabilizing the electric characteristic of a liquid crystal display element over a long period of time. The oxazine compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the oxazine compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40% by weight, and still more preferably 1% by weight to 20% by weight.

The oxazine compound is preferably an oxazine compound that is soluble in a solvent for dissolving polyamic acid or a derivative thereof and has ring-opening polymerizability. Regarding preferred oxazine compounds, oxazine compounds represented by formula (OX-3-1), formula (OX-3-9), and formula (OX-3-10); and Japanese Patent Laid-Open No. 2007-286597 2013-242526, and the oxazine compound disclosed in Japanese Patent Application Laid-Open No. 2013-242526.

＜Oxazoline compounds＞

For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one kind of compound, or two or more kinds of compounds. For the above purpose, the content of the oxazoline compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40% by weight, and even more preferably 1% by weight relative to the polyamic acid or its derivatives. ~20% by weight. Preferable oxazoline compounds include oxazoline compounds disclosed in JP-A-2010-054872 and JP-A-2013-242526. More preferably, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene is mentioned.

＜Epoxy compound＞

For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics of a liquid crystal display element over a long period of time, for the purpose of increasing the hardness of a film, or for the purpose of improving adhesion with a sealant. The epoxy compound may be one kind of compound, or two or more kinds of compounds. For the purpose, the content of the epoxy compound is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 20% by weight, and even more preferably 1% by weight to 10% by weight.

As the epoxy compound, various compounds having one or two or more epoxy rings in the molecule can be used.

In order to achieve the purpose of increasing the hardness of the film or the purpose of improving the adhesion with the sealant, it is preferably a compound having two or more epoxy rings in the molecule, more preferably a compound having three or four epoxy rings .

Examples of the epoxy compound include epoxy compounds disclosed in JP-A-2009-175715, JP-A-2013-242526, JP-A-2016-170409, and International Publication No. 2017/217413. Examples of preferred epoxy compounds include: N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3,3',4,4'- Diepoxy) bicyclohexyl, 1,4-butanediol glycidyl ether, tris(2,3-epoxypropyl) isocyanurate, 1,3-bis(N,N-diglycidyl) aminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-m-xylylenediamine. More preferably 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, Ethoxysilane. In addition to this, an oligomer or polymer having an epoxy ring may also be added. As the oligomer or polymer having an epoxy ring, the oligomer or polymer disclosed in JP-A-2013-242526 can be used.

＜Silane compound＞

For example, the liquid crystal aligning agent of this invention may contain a silane compound further for the purpose of improving the adhesiveness with a board|substrate and a sealing compound. For the purpose, the content of the silane compound is preferably 0.1% by weight to 30% by weight, more preferably 0.5% by weight to 20% by weight, and even more preferably 0.5% by weight to 10% by weight relative to the polyamic acid or its derivatives. weight%.

As the silane compound, silane coupling agents disclosed in JP-A-2013-242526, JP-A-2015-212807, JP-A-2018-173545, and International Publication No. 2018/181566 can be used. As a preferred silane coupling agent, can enumerate: 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl Trimethoxysilane, p-Aminophenyltrimethoxysilane, 3-Aminopropyltriethoxysilane, 3-Glycidoxypropylmethyldiethoxysilane, 3-Isocyanatopropyltriethoxysilane oxysilane or 3-ureidopropyltriethoxysilane.

In addition to the additives described above, for the purpose of increasing the strength of the alignment film or stabilizing the electrical characteristics of the liquid crystal display element for a long time, a compound having a cyclocarbonate group, a compound having a hydroxyalkylamide site or a hydroxyl group may be added. compound of. Specific compounds include compounds disclosed in JP-A No. 2016-118753 and International Publication No. 2017/110976. As a preferable compound, following formula (HD-1) - a formula (HD-4) are mentioned. These compounds are preferably 0.5% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, and still more preferably 1% by weight to 10% by weight based on the polyamic acid or its derivative.

In addition, an antistatic agent can also be used when antistatic needs to be improved, and an imidization catalyst can also be used when imidation is performed at low temperature. As an imidation catalyst, the imidation catalyst disclosed by Unexamined-Japanese-Patent No. 2013-242526 is mentioned.

＜Liquid crystal aligning film＞

Next, the liquid crystal aligning film of this invention is demonstrated. The liquid crystal aligning film of this invention is formed using the liquid crystal aligning agent of this invention. When heating and baking is performed in the process of forming a liquid crystal aligning film using the liquid crystal aligning agent of this invention, an imidation reaction will arise and a polyimide-type liquid crystal aligning film will be formed. The liquid crystal aligning agent of this invention is suitable for the liquid crystal aligning agent for photo-alignment, and the photo-alignment method can be applied to the orientation process in the process of forming a liquid crystal aligning film.

Hereinafter, the formation method of the liquid crystal aligning film using the liquid crystal aligning agent for photo-alignment of this invention is demonstrated.

The liquid crystal aligning film of this invention can be obtained by the normal method of producing a liquid crystal aligning film from the liquid crystal aligning agent for photoalignment. For example, the liquid crystal aligning film of the present invention can be obtained through the following steps: the process of forming the coating film of the liquid crystal aligning agent for photo-alignment of the present invention, the process of drying the coating film to form a film of the liquid crystal aligning agent, and the process of forming a film of the liquid crystal aligning agent. The process of irradiating the film of an alignment agent with light and providing anisotropy, and the process of heating and baking the film of the liquid crystal aligning agent which provided anisotropy.

A coating film can be formed by apply|coating the liquid crystal aligning agent of this invention on the board|substrate in a liquid crystal display element similarly to preparation of a normal liquid crystal aligning film. The substrate may be provided with electrodes such as indium tin oxide (Indium Tin Oxide, ITO), indium zinc oxide (In ₂ O ₃ -ZnO, IZO), indium gallium zinc oxide (In-Ga-ZnO ₄ , IGZO) electrodes or color Substrates made of glass, silicon nitride, acrylic, polycarbonate, polyimide, etc., such as optical filters.

As a method of applying a liquid crystal aligning agent on a substrate, generally, a spinner method, a printing method, a dipping method, a dropping method, an inkjet method, etc. are known. These methods can also be similarly applied to the present invention.

In the heating and drying process, a method of heat-treating in an oven or an infrared furnace, a method of heat-treating on a hot plate, and the like are generally known. The heat drying step is preferably carried out at a temperature within a range in which the solvent can evaporate, and more preferably carried out at a relatively lower temperature than the temperature in the heat firing step. Specifically, the heat drying temperature is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 120°C.

The heating and calcining step can be performed under the conditions required for the imidization reaction of polyamic acid or its derivatives. Calcination of a coating film generally includes a method of heat-treating in an oven or an infrared furnace, a method of heat-treating on a hot plate, and the like. These methods can also be similarly applied to the present invention. Usually, it is preferable to carry out at a temperature of about 90°C to 300°C for 1 minute to 3 hours, more preferably 120°C to 280°C, and still more preferably 150°C to 250°C.

When emphasis is placed on improving the anisotropy of the film or the afterimage characteristics when producing a liquid crystal display element, it is preferable to slowly increase the temperature of the heating process. Calcination is performed by heating, or heating is performed by changing the temperature from a low temperature to a high temperature. In addition, two heating methods may be combined and performed.

When heating and calcining is performed multiple times at different temperatures, a plurality of heating devices set to different temperatures may be used, or one heating device may be used to sequentially change to different temperatures.

When heating and calcination is performed at different temperatures for multiple times, it is preferably performed at the initial calcination temperature of 90°C to 180°C, and preferably at the final temperature of 185°C to 300°C. For example, after heating and calcination at 110°C, heating and calcination at 220°C; after heating and calcination at 110°C, heating and calcination at 230°C; After heating and calcination at 150°C, heat and calcine at 200°C; after heating and calcination at 150°C, heat and calcine at 220°C; After calcination, heat and calcine at 200°C. Furthermore, it is also preferable to perform heating and calcination while gradually increasing the temperature in increasing stages. When heating and firing is performed in two or more steps while changing the heating temperature, the heating time in each heating step is preferably 5 minutes to 30 minutes.

When firing by changing the temperature from a low temperature to a high temperature, the initial temperature is preferably 90°C to 180°C. The final temperature is preferably 185°C to 300°C, more preferably 190°C to 230°C. The heating time is preferably 5 minutes to 60 minutes, more preferably 20 minutes to 60 minutes. The rate of temperature rise can be set to, for example, 0.5° C./min to 40° C./min. The rate of temperature increase during temperature increase may not be fixed.

In the method for forming a liquid crystal aligning film of the present invention, a known photo-alignment method can be suitably used as a method for imparting anisotropy to a film in order to align liquid crystals in one direction with respect to the horizontal direction and/or the vertical direction.

The formation method of the liquid crystal aligning film of this invention by the photo-alignment method is demonstrated in detail. The liquid crystal aligning film of this invention using the photo-alignment method can be formed by irradiating light to the film after heating and drying a coating film, providing anisotropy to a film, and heating and baking the said film. Alternatively, it can be formed by heat-drying the coating film, performing heat-calcination, and then irradiating the thin film with light.

Furthermore, in order to improve the liquid-crystal aligning ability of a liquid crystal aligning film, you may irradiate light, heating a coating film. Irradiation of light may be performed in the step of heat-drying the coating film or the step of heat-calcining, or may be performed between the heat-drying step and the heat-calcining step. For the heating temperature at the time of irradiating light in the step of heat-drying the coating film or the step of heating and firing, refer to the description of the heat-drying step or the step of heating and firing. The heating temperature at the time of light irradiation between the heat drying step and the heat firing step is preferably in the range of 30°C to 150°C, more preferably in the range of 50°C to 110°C.

As the light used in the photoirradiation step in the photo-alignment method, for example, ultraviolet rays or visible light including light having a wavelength of 150 nm to 800 nm can be used. These lights are not particularly limited as long as they can impart liquid crystal alignment ability to the film, but polarized light is preferred, and linearly polarized light is more preferred when a strong orientation-regulating force for liquid crystals is intended to be exhibited.

The irradiation amount of polarized light in the light irradiation step is preferably 0.05 J/cm ² to 10 J/cm ² , more preferably 0.1 J/cm ² to 5 J/cm ² . In addition, the wavelength of polarized light is preferably appropriately changed according to the compound having a photoreactive structure. When using the compound represented by formula (2), the wavelength of polarized light is preferably 200 nm to 400 nm, more preferably 300 nm to 400 nm. When using the compound represented by formula (3), the wavelength of polarized light is preferably 150 nm to 350 nm, more preferably 200 nm to 300 nm. The angle of irradiation of polarized light on the film surface is not particularly limited, but it is preferably as perpendicular as possible to the film surface from the viewpoint of shortening the alignment treatment time when a strong alignment-regulating force for liquid crystals is to be exhibited. Moreover, the liquid crystal aligning film of this invention can align a liquid crystal in the direction which becomes a right angle with respect to the polarization direction of linearly polarized light by irradiating linearly polarized light.

As the light source used in the light irradiation process, ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, deep ultraviolet (Deep UV) lamps, halogen lamps, metal halide lamps, high power metal halide lamps, Xenon lamp, mercury xenon lamp, excimer lamp, KrF excimer laser, fluorescent lamp, light emitting diode (LED) lamp, sodium lamp, microwave discharged electrodeless lamp, etc.

The liquid crystal aligning film of this invention can be obtained suitably by the method further including the process other than the said process.

Although the liquid crystal aligning film of this invention does not make the process of washing|cleaning the film after baking or light irradiation with a washing|cleaning liquid essential, you may provide a washing|cleaning process according to the situation of another process. Examples of the cleaning method using a cleaning liquid include brushing, jet spray, steam cleaning, ultrasonic cleaning, and the like. These methods can be used alone or in combination. As a cleaning solution, pure water; or various alcohols such as methanol, ethanol, and isopropanol; aromatic hydrocarbons such as benzene, toluene, and xylene; halogen-based solvents such as methylene chloride; acetone, methyl ethyl alcohol, etc. Ketones such as ketones are, but not limited to, these. Of course, as these washing liquids, sufficiently purified washing liquids with few impurities can be used. Such a cleaning method can also be applied to the cleaning step in the formation of the liquid crystal aligning film of the present invention.

In order to improve the liquid crystal orientation ability of the liquid crystal aligning film of this invention, the annealing process by heat or light can be used before and after a heating baking process, or before and after polarized light or nonpolarized light irradiation. In the annealing treatment, the annealing temperature is 30° C. to 180° C., preferably 50° C. to 150° C., and the annealing time is preferably 1 minute to 2 hours. In addition, examples of the annealing light used in the annealing treatment include UV lamps, fluorescent lamps, and LED lamps. The amount of light irradiation is preferably 0.3 J/cm ² to 10 J/cm ² .

The film thickness of the liquid crystal aligning film of the present invention is not particularly limited, but is preferably 10 nm to 300 nm, more preferably 30 nm to 150 nm. The film thickness of the liquid crystal aligning film of this invention can be measured with known film thickness measuring devices, such as a profiler and an ellipsometer (ellipsometer).

The liquid crystal aligning film of the present invention is characterized by having particularly large orientation anisotropy. The magnitude of such anisotropy can be evaluated by the method using polarized light IR described in JP-A-2005-275364 and the like. In addition, it can also be evaluated by a method using ellipsometry. In detail, the retardation value of a liquid crystal aligning film can be measured with a spectroscopic ellipsometer. The retardation value of the film increases in proportion to the degree of orientation of the polymer backbone.

The liquid crystal aligning film of this invention can be used suitably for the orientation control of the liquid crystal composition in a liquid crystal display element. In addition to the orientation application of the liquid crystal composition of the liquid crystal display element, it can also be used for the orientation control of the liquid crystal material in all other liquid crystal elements such as liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters. In addition, since the liquid crystal aligning film of the present invention has large anisotropy, it can be used alone as an optical compensation material.

＜Liquid crystal display elements＞

Next, the liquid crystal display element of the present invention will be described. The liquid crystal display element of this invention is characterized by having the liquid crystal aligning film of this invention, and can realize high display quality because of favorable contrast.

The liquid crystal display element of the present invention will be described in detail. In the present invention, the liquid crystal alignment film includes the liquid crystal alignment film of the present invention in the following liquid crystal display element, the liquid crystal display element includes a pair of substrates arranged facing each other, and the liquid crystal alignment film is formed on each of the opposing surfaces of the pair of substrates. The electrodes on one or both of them, the liquid crystal alignment film formed on the respective facing surfaces of the pair of substrates, the liquid crystal layer formed between the pair of substrates, and a pair of electrodes arranged to sandwich the facing substrates For polarizing film, backlight and driving device.

The electrodes are not particularly limited as long as they are formed on one surface of the substrate. Such an electrode includes, for example, ITO or a metal vapor-deposited film. In addition, the electrodes may be formed on the entire surface of one of the substrates, or may be formed in a patterned desired shape, for example. The desired shape of the electrode includes, for example, a comb shape or a zigzag structure. The electrodes can be formed on one of the pair of substrates, or on both substrates. The form of electrode formation differs depending on the type of liquid crystal display element. For example, in the case of an IPS type liquid crystal display element (transverse electric field type liquid crystal display element), the electrode is arranged on one of the pair of substrates, and on the other liquid crystal display element. In the case of a display element, electrodes are arranged on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or the electrode.

In the case of a parallel-aligned liquid crystal display element (for example, IPS, FFS, etc.), as a structure, from the backlight side, at least a backlight, a first polarizing film, a first substrate, a first liquid crystal alignment film, a liquid crystal layer, a second The substrate, the second polarizing film, the polarizing axis of the polarizing film is set in such a way that the polarizing axis (direction of polarized light absorption) of the first polarizing film and the polarizing axis of the second polarizing film intersect (preferably orthogonal). In this case, the polarizing axis of the first polarizing film may be arranged parallel to or perpendicular to the liquid crystal alignment direction. A liquid crystal display element in which the polarization axis of the first polarizing film is parallel to the liquid crystal alignment direction is called O-mode, and a liquid crystal display element in which the polarization axis is perpendicular to each other is called E-mode. The liquid crystal aligning film of this invention can also be applied to any of O-mode and E-mode, and can be selected according to the purpose.

Compounds having dichroism can be used among a large number of photoisomerization-type materials. Therefore, when the polarization axis of the polarized light irradiated in order to add anisotropy to the liquid crystal aligning agent is parallel to and consistent with the polarization axis of the polarized light from the polarizing film arranged on the backlight side (in the case of using the liquid crystal aligning agent of the present invention , when it is an O-mode configuration), the transmittance of the light absorption wavelength region of the liquid crystal aligning film increases. Therefore, the transmittance of the liquid crystal display element can be further improved.

The said liquid crystal layer is formed so that the liquid crystal composition may be sandwiched between the said pair of board|substrates in which the surface on which the liquid crystal aligning film was formed opposes. In the formation of the liquid crystal layer, a spacer that exists between the pair of substrates and forms an appropriate interval may be used, if necessary, such as fine particles or a resin sheet.

As a method for forming a liquid crystal layer, a vacuum injection method and a liquid crystal drop filling (One Drop Fill, ODF) method are known.

In the vacuum injection method, a gap (cell gap) is provided so that the liquid crystal aligning film faces face each other, and a sealant is printed while leaving an injection port of the liquid crystal, and the substrates are bonded together. Liquid crystal is injected into the cell gap divided by the surface of the substrate and the sealant using vacuum differential pressure, and then the injection port is closed to manufacture a liquid crystal display element.

In the ODF method, a sealant is printed on the outer periphery of the liquid crystal aligning film surface of one of a pair of substrates, liquid crystal is dropped on the inner region of the sealant, and the other substrate is adhered so that the liquid crystal aligning film faces face each other. Then, the liquid crystal is press-spread over the entire surface of the substrate, and then, the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant, thereby manufacturing a liquid crystal display element.

As for the sealant used for bonding the substrates, a thermosetting type is known in addition to a UV-curable type. Printing of the sealant can be performed, for example, by screen printing.

The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy can be used. Preferred liquid crystal compositions with positive dielectric anisotropy include: Japanese Patent 3086228, Japanese Patent 2635435, Japanese Patent Kokai Hei 5-501735, Japanese Patent Kokai Hei 8-157826, Japanese Patent Kokai Hei 8-231960, Japanese Patent Kokai Hei 8-231960, Japanese Patent Laid-Open No. 9-241644 (EP885272A1), Japanese Patent No. 9-302346 (EP806466A1), Japanese Patent No. 8-199168 (EP722998A1), Japanese Patent No. 9-235552, Japanese Patent No. 9-255956, Japanese Patent JP-9-241643 (EP885271A1), JP-10-204016 (EP844229A1), JP-10-204436, JP-10-231482, JP-2000-087040, JP-2001- 48822 et al. disclosed in the liquid crystal composition.

Preferred examples of the liquid crystal composition having negative dielectric anisotropy include: Japanese Patent Laid-Open No. 57-114532, Japanese Patent Laid-Open Hei 2-4725, Japanese Patent Laid-Open No. 4-224885, Japanese Patent Laid-Open No. JP-A-8-40953, JP-A-8-104869, JP-A-10-168076, JP-A-10-168453, JP-A-10-236989, JP-A-10-236990, JP-A-10 -236992, Japanese Patent Laid-Open No. 10-236993, Japanese Patent No. 10-236994, Japanese Patent No. 10-237000, Japanese Patent No. 10-237004, Japanese Patent No. 10-237024, Japanese Patent No. 10-237035 , Japanese Patent Kokai Hei 10-237075, Japanese Patent Kokai Hei 10-237076, Japanese Patent Kokai Hei 10-237448 (EP967261A1), Japanese Patent Kokai Hei 10-287874, Japanese Patent Kokai Hei 10-287875, Japanese Patent Kokai Hei 10- 291945, Japanese Patent Laid-Open 11-029581, Japanese Patent Laid-Open 11-080049, Japanese Patent Laid-Open 2000-256307, Japanese Patent Laid-Open 2001-019965, Japanese Patent Laid-Open 2001-072626, Japanese Patent Laid-Open 2001-192657, Liquid crystal combination disclosed in Japanese Patent Laid-Open 2010-037428, International Publication 2011/024666, International Publication 2010/072370, Japanese Patent Laid-Open 2010-537010, Japanese Patent Laid-Open 2012-077201, Japanese Patent Laid-Open 2009-084362, etc. things.

Even if one or more optically active compounds are added to a liquid crystal composition having positive or negative dielectric anisotropy and used, there is no influence at all.

Moreover, for example, the liquid crystal composition used for the liquid crystal display element of this invention may further add an additive from a viewpoint of orientation improvement, for example. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, and the like. Preferable photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, antifoaming agents, polymerization initiators, and polymerization inhibitors include compounds disclosed in International Publication No. 2015/146330 and the like.

In order to be suitable for a liquid crystal display device in a polymer sustained alignment (PSA) mode, a polymerizable compound may be mixed in the liquid crystal composition. Preferred examples of polymerizable compounds include acrylates, methacrylates, vinyl compounds, vinyloxy compounds, propenyl ethers, epoxy compounds (oxirane, oxetane), vinyl ketones, etc. Compounds capable of polymerizing groups. Preferable compounds include compounds disclosed in International Publication No. 2015/146330 and the like.

[Example]

Hereinafter, the present invention will be described through examples. In addition, the evaluation methods and compounds used in the examples are as follows.

Weight average molecular weight (Mw)

The weight average molecular weight of a polyamic acid is calculated|required by the GPC method using 2695 separation module · 2414 differential refractometers (made by Waters), and it performs polystyrene conversion. The obtained polyamic acid was diluted with a phosphoric acid-dimethylformamide (Dimethyl Formamide, DMF) mixed solution (phosphoric acid/DMF=0.6/100: weight ratio) so that the polyamic acid concentration became about 2% by weight. . HSPgel RT MB-M (manufactured by Waters) was used as a column, and the mixed solution was used as a developing solvent, and the measurement was performed at a column temperature of 50° C. and a flow rate of 0.40 mL/min. As the standard polystyrene, TSK standard polystyrene manufactured by Tosoh Co., Ltd. was used.

＜Tetracarboxylic dianhydride＞

＜Diamine＞

<Solvent>

NMP: N-methyl-2-pyrrolidone

BC: Butyl cellosolve (ethylene glycol monobutyl ether)

＜Additives＞

Additive 1: 1,3-bis(4,5-dihydro-2-oxazolyl)benzene

Additive 2: (3,3',4,4'-diepoxy)bicyclohexyl

The compound represented by formula (1-1) was obtained by referring to the method described in International Publication No. 2019/172460.

The compound represented by formula (1-2) was obtained by referring to the method described in International Publication No. 2018/147373.

The compound represented by the formula (3-4-1) is a compound in which the two esters on the cyclopropane ring in the formula (3-4) are trans-configured. The compound represented by the formula (3-4-1) is obtained by the following method.

After cooling the ethanol (100mL) solution of trans (trans)-1,2-cyclopropanedicarboxylate (10.0g, 53.7mmol) in an ice bath, add sodium hydroxide (8.60g, 215mmol) in water ( 100mL) solution. After slowly warming the mixture to room temperature over 1 hour, the mixture was stirred for 15 hours. After the reaction, the reaction mixture was concentrated under reduced pressure, and ethanol was distilled off. The residue was cooled in an ice bath again, concentrated hydrochloric acid (20 mL) was added, and excess salt was added, and extracted with ethyl acetate (100 mL×8 times). The organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure to obtain a white solid of trans-1,2-cyclopropanedicarboxylic acid (yield: 6.44 g, yield: 92%).

¹ H-NMR (400MHz, dimethyl sulfoxide (DMSO)-d ₆ ): δ1.89-1.77 (m, 2H), 1.26-1.14 (m, 2H).

Thionyl chloride (30 mL) was added to trans-1,2-cyclopropanedicarboxylic acid (6.00 g, 46.1 mmol), stirred at 70°C for 4 hours, concentrated under reduced pressure, and the thionyl chloride was distilled off , thus obtaining crude trans-1,2-cyclopropanedicarboxylic acid chloride. The carboxylic acid chloride was made into tetrahydrofuran (Tetrahydrofuran, THF) (90 mL) solution, and all of them were used in the following reaction.

Under an argon atmosphere, triethylamine (16.3 g, 161 mmol) was added to a THF (100 mL) solution of 4-nitrophenol (13.5 g, 96.8 mmol), followed by cooling in an ice bath. While vigorously stirring the mixture, a THF solution of the prepared carboxylic acid chloride was added over 5 minutes, then allowed to warm to room temperature and stirred at room temperature for 2.5 hours. Saturated ammonium chloride aqueous solution (100 mL) was added to the reaction mixture, followed by concentration under reduced pressure. The residue was extracted with ethyl acetate (300 mL×3 times), and washed with saturated sodium bicarbonate (300 mL). The organic layer was dried using anhydrous sodium sulfate, and then concentrated under reduced pressure to obtain a pale yellow solid (7.36 g ). Furthermore, the solid remaining in the water layer was collected by filtration and washed with water to recover trans-1,2-cyclopropanedicarboxylate bis(4-nitrophenyl) ester as a light yellow solid (6.72 g) , combined with the 7.36g, thus obtaining dinitro compound 1 (trans-1,2-cyclopropanedicarboxylic acid bis(4-nitrophenyl) ester) (total yield 14.1g, yield 82%) .

¹ H-NMR (400MHz, CDCl ₃ ): δ8.31(d, J=9.2Hz, 4H), 7.35(d, J=9.2Hz, 4H), 2.66-2.59(m, 2H), 1.86-1.78( m,2H).

Under an argon atmosphere, add tin (II) chloride dihydrate (84.8 g, 376 mmol) to a solution of dinitro compound 1 (14.0 g, 37.6 mmol) in ethyl acetate (370 mL), and stir under heating and reflux 4 hours. After the reaction, the reaction mixture was cooled to room temperature, and the reaction mixture was added to saturated aqueous sodium bicarbonate (1 L), and then extracted with ethyl acetate (300 mL×3 times). The obtained organic layer was washed successively with saturated aqueous sodium bicarbonate solution (300 mL) and saturated brine (300 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Using a mixed solvent of chloroform: methanol as an eluent, while changing the ratio in the range of 100:0 to 95:5, the obtained residue was purified by silica gel column chromatography to obtain the target 2 White solid of amine compound (3-4-1) (yield: 8.50 g, yield: 72%). Due to the existence of enantiomers (Enantiomers) in the trans-1,2-cyclopropane diethyl carboxylate of the starting material, it is speculated that the material obtained in the described manner is actually represented by the formula (3-4-1). A mixture of the indicated compound and its enantiomer was used without isolating the two in this example.

¹ H-NMR (400MHz, CDCl ₃ ): δ6.90(d, J=8.8Hz, 4H), 6.67(d, J=8.8Hz, 4H), 3.64(brs, 4H), 2.53-2.47(m, 2H),1.71-1.65(m,2H).

Preparation of varnish

The varnish used in this example was prepared according to the following procedure. Here, varnish A1 to varnish A7 and varnish R1 to varnish R3 prepared in Production Example 1 to Production Example 10 of the varnish are polyamides obtained by reacting at least one compound having a photoreactive chemical structure as a raw material. acid solution. These varnishes express anisotropy in the film by irradiating polarized light of an appropriate wavelength after film formation. The varnishes B1 to B3 for blending prepared in Preparation Examples 11 to 13 of the varnishes are solutions of polyamic acids obtained without using a compound having a photoreactive chemical structure as raw materials, and are mixed with varnishes A1 to Varnish A7 or varnish R1 - varnish R3 were blended and used for preparation of a blend type liquid crystal aligning agent (alignment agent 7-alignment agent 11 mentioned later, alignment agent 4 for comparison - alignment agent 5 for comparison).

[Preparation Example 1 of Varnish] Preparation of Varnish A1

2.058 g of the compound represented by formula (2-1-1) was put into the 100 mL three-necked flask equipped with the stirring blade and the nitrogen introduction tube, and 34.0 g of N-methyl-2-pyrrolidone was added and stirred. 1.971 g of the compound represented by the formula (1-1) and 1.971 g of the compound represented by the formula (AN-4-17) (m=8) were added to the solution, and stirred at room temperature for 12 hours. Add 30.0 g of N-methyl-2-pyrrolidone (N-Methyl-2-pyrrolidone, NMP) and 30.0 g of butyl cellosolve (ButylCellosolve, BC) to it, and heat and stir the solution at 60° C. until it becomes Until the weight average molecular weight of the polymer of the solute becomes a desired weight average molecular weight, the weight average molecular weight of the solute is about 13,400, and the varnish A1 whose resin content concentration (solid content concentration) is 6 weight% was obtained.

[Preparation Example 2 to Preparation Example 13 of Varnish] Preparation of Varnish A2 to Varnish A7, Varnish R1 to Varnish R3, Varnish B1 to Varnish B3

As shown in Table 1, except that the compounds used as diamine and tetracarboxylic dianhydride were changed, varnish A2 to varnish A7 with a solid content concentration of 6% by weight and a varnish for comparison were prepared in the same manner as in Preparation Example 1. R1 ~ varnish R3. As shown in Table 2, except having changed the compound used as a diamine and a tetracarboxylic dianhydride, it carried out similarly to the preparation example 1, and prepared varnish B1 - varnish B3. In varnish B1 - varnish B3, the conditions of heating and stirring were adjusted so that the weight average molecular weight of a polymer might be about 50,000. Table 1 and Table 2 show the weight average molecular weight of the produced polymer. In addition, in Table 1, regarding the preparation examples in which two or more compounds are described as diamines, it means that all the above-mentioned compounds are combined as diamines, and in the preparation examples in which two or more compounds are described as tetracarboxylic dianhydrides. The preparation example refers to combining all the above-mentioned compounds as tetracarboxylic dianhydride. The numerical values in the square brackets represent the compounding ratio (mol %), and the empty column means that the compound corresponding to the column is not used. In Table 2, the same is true.

[Table 1]

[Table 2]

[Example 1]

Alignment agent 1 was prepared by diluting and stirring varnish A1 with NMP/BC mixed solution (NMP/BC=7/3 weight ratio) so that solid content concentration might become 4 weight%. The prepared liquid crystal aligning agent was coated on a glass substrate with FFS electrodes and a glass substrate with a column spacer by a spinner method. After coating, the substrate was heated at 60° C. for 80 seconds to evaporate the solvent, and then, using Multi-Light ML-501C/B manufactured by Ushio Electric Co., Ltd., the The direction is irradiated with linearly polarized light of ultraviolet rays through a polarizing plate in the polarization wavelength range of 300nm to 450nm and a short-wavelength cut-off filter with a cut-on wavelength of 280nm. The exposure energy at this time is measured by using an ultraviolet integrated light meter UIT-150 (photoreceiver: UVD-S365) manufactured by Ushio Electric Co., Ltd., so that it becomes a "standard exposure amount" at a wavelength of 365nm 2.0±0.1J/ The exposure time was adjusted by cm ² . Thereafter, a calcination treatment was performed at 220° C. for 30 minutes to form an alignment film having a film thickness of about 100 nm. Then, these two board|substrates in which the alignment film was formed were bonded together so that the surface in which the liquid crystal alignment film was formed may face, and the gap for injecting a liquid crystal composition may be provided between the opposing liquid crystal alignment films. At this time, the polarization direction of the linearly polarized light irradiated to each liquid crystal aligning film was made parallel. The positive type liquid crystal composition A was injected into these cells, and the liquid crystal cell (liquid crystal display element) with a cell thickness of 5 micrometers was produced. The luminance-voltage characteristics (BV characteristics) of the produced liquid crystal cell were measured, and the contrast ratio (Contrast Ratio, CR) was calculated|required using the ratio of the minimum luminance and the maximum luminance. The larger the value of CR, the clearer the display of light and shade, and the better the contrast.

CR＝ _Bmax / _Bmin

In the formula, B _max represents the maximum brightness in the BV characteristic, and B _min represents the minimum brightness in the BV characteristic.

Contrast (CR) was evaluated according to the following criteria.

CR is 3000 or more:〇

CR less than 3000: ×

Next, except that the exposure time was adjusted so that the amount of linearly polarized light became "low exposure" 0.8 ± 0.1 J/cm ² lower than the standard exposure amount, a liquid crystal cell was produced in exactly the same way, and contrast. When the contrast is good in both the standard exposure amount and the low exposure amount, it means that the range of the suitable polarized light irradiation energy in liquid crystal display element manufacture is wider, and it means that it is more preferable as a liquid crystal aligning agent for photo-alignment.

In addition, the evaluation results of the contrast of Examples 1 to 11 and Comparative Examples 1 to 5 are described in Table 3 and Table 4 together with the preparation conditions of the varnish.

[Example 2]

Alignment agent 2 was prepared in the same manner as in Example 1, except that varnish A2 was used instead of varnish A1, and additive 1 was added so that it might become 5 weight part with respect to solid content, adding NMP/BC mixed solution. About the alignment agent 2, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed.

[Example 3-Example 5, Comparative Example 1-Comparative Example 2]

Except having used the varnish shown in Table 3 instead of varnish A1, it carried out similarly to Example 1, and prepared the alignment agent 3 - the alignment agent 5 and the comparison alignment agent 1 - the comparison alignment agent 2. About the alignment agent 3 - the alignment agent 5 and the comparison alignment agent 1 - the comparison alignment agent 2, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed.

[Example 6, Comparative Example 3]

Except having used the varnish shown in Table 3 instead of varnish A1, it carried out similarly to Example 1, and prepared the alignment agent 6 and the comparison alignment agent 3. Alignment agent 6 and comparative alignment agent 3 were irradiated with linearly polarized light of ultraviolet rays from a direction perpendicular to the substrate through a polarizing plate in the polarization wavelength range of 230 nm to 310 nm, and the exposure energy was obtained by using an ultraviolet cumulative meter manufactured by Ushio Electric Co., Ltd. Light meter UIT-150 (optical receiver: UVD-S254) to measure the amount of light, and adjust the exposure time of linearly polarized light in such a way that it becomes the "standard exposure amount" 0.5±0.1J/ ^cm2 at a wavelength of 254nm. A liquid crystal cell was fabricated in the same manner as in Example 1, and the contrast was measured and evaluated. Next, except that the exposure time was adjusted so that the amount of linearly polarized light became "low exposure" 0.2 ± 0.1 J/cm ² lower than the standard exposure amount, a liquid crystal cell was produced in exactly the same way, and contrast.

[Example 7]

Varnish A1 and varnish B1 were blended at a weight ratio of 3:7 to obtain a blended varnish with a solid content concentration of 6% by weight. Furthermore, it diluted and stirred with the NMP/BC mixed solution (NMP/BC=7/3 weight ratio) so that the solid content concentration might become 4 weight%, and the alignment agent 7 was prepared. Except having used the alignment agent as the alignment agent 7 instead of the alignment agent 1, it carried out similarly to Example 1, and produced the liquid crystal cell, and performed the measurement and evaluation of contrast.

[Example 8]

Alignment agent 8 was prepared in the same manner as in Example 7, except that varnish A3 was used instead of varnish A1, and additive 2 was added so that it might become 5 weight part with respect to solid content, adding NMP/BC mixed solution. About the alignment agent 8, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed.

[Example 9 to Example 10, Comparative Example 4]

Using the varnish shown in Table 4 instead of varnish A1 and varnish B1, except that the blending ratio was changed to the blending ratio shown in Table 4, alignment agents 9 to 10 were prepared in the same manner as in Example 7 and compared Alignment agent 4. For example, in Example 9 in Table 4, it means that varnish A4 and varnish B2 for blending were blended at the weight ratio of 4:6 that a blending ratio is "4:6". About the alignment agent 9 - the alignment agent 10, and the comparison alignment agent 4, the liquid crystal cell was produced similarly to Example 1, and the measurement and evaluation of contrast were performed.

[Example 11, Comparative Example 5]

Alignment agent 11 and comparative alignment agent 5 were prepared in the same manner as in Example 7, except that the varnish shown in Table 4 was used instead of varnish A1 and varnish B1, and the blending ratio was changed to the blending ratio shown in Table 4. . About the alignment agent 11 and the comparison alignment agent 5, the liquid crystal cell was produced similarly to Example 6, and the measurement and evaluation of contrast were performed.

<Positive type liquid crystal composition A>

(physical value)

Phase transition temperature NI: 100.1°C, dielectric anisotropy Δε: 5.1, refractive index anisotropy Δn: 0.093, viscosity η: 25.6mPa·s.

[table 3]

[Table 4]

The contrast in Examples 1 to 11 was evaluated as "◯" in any of the liquid crystal cells produced by the standard exposure amount and the low exposure amount. It can be seen that the polymer obtained by polymerizing the tetracarboxylic dianhydride represented by the formula (1-1) or the formula (1-2) and the compound having a photoreactive structure is used as a liquid crystal aligning agent for photo-alignment, even if the exposure amount Even if it is small, the alignment film of the liquid crystal display element which can realize a high contrast ratio can be obtained.

[industrial availability]

When the liquid crystal aligning agent for photo-alignment of this invention is used, even when the exposure energy of a photo-alignment process is little, the liquid crystal aligning film which realizes the liquid crystal display element of high contrast can be manufactured. The liquid crystal aligning agent for photo-alignment of this invention can be suitably applied to a transverse electric field type liquid crystal display element.

Claims (10)

1. A liquid crystal aligning agent for photo-alignment comprising at least one polymer and a solvent, wherein at least one of the polymers is a polymer obtained by reacting a tetracarboxylic acid dianhydride with a diamine,

a raw material composition used as a raw material of the polymer obtained by reacting the tetracarboxylic acid dianhydrides with the diamines, the raw material composition containing at least one compound represented by the formula (1-1) or (1-2) and a compound having a photoreactive structure that imparts liquid crystal alignment properties to an alignment film by photoreaction;

2. the liquid crystal aligning agent according to claim 1, wherein the photoreaction is at least one of photoisomerization, photoFries rearrangement, photodecomposition, and photodimerization.

3. The liquid crystal aligning agent for photoalignment according to claim 1 or 2, wherein the compound having a photoreactive structure is at least one compound represented by formula (2);

in the formula (2), X is alkylene with 1-12 carbon atoms, and when the carbon number of the alkylene is more than 2, - (CH) ₂ ) ₂ One or more non-adjacent of-may be substituted by-O-or-NH-,

R ^a and R ^b Each independently a hydrogen atom, a methyl group, a methoxy group, a trifluoromethyl group, a fluorine atom, a methoxycarbonyl group or a monovalent group represented by the formula (P1-1) or the formula (P1-2),

R ^c independently represents a hydrogen atom, a methyl group, a methoxy group, a trifluoromethyl group, a fluorine atom, or a monovalent group represented by the formula (P1-1) or the formula (P1-2), j is 0 or 1, a to c independently represent 0An integer of-2, and,

in the formulae (P1-1) and (P1-2), R ^6a 、R ^7a And R ^8a Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, or a substituted or unsubstituted alkoxycarbonyl group, R ^6a 、R ^7a And R ^8a May be the same as or different from each other, represents a bonding position on the benzene ring in the formula (2),

in the formula (2), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position on the ring is arbitrary.

4. The liquid crystal aligning agent for photoalignment according to claim 3, wherein the compound represented by formula (2) is any one of formula (2-1) to formula (2-3);

in the formula (2-1), R ^1a And R ^1c Each independently represents a hydrogen atom or a monovalent group represented by the formula (P1-1) or the formula (P1-2),

in the formula (2-2), R ^2a And R ^2b Each independently represents a hydrogen atom or a monovalent group represented by the formula (P1-1) or the formula (P1-2), R ^2c Each independently is a hydrogen atom, a methyl group, a methoxy group, a trifluoromethyl group, a fluorine atom, X ₁ Is an alkylene group having 1 to 12 carbon atoms, and when the carbon number of the alkylene group is 2 or more, - (CH) ₂ ) ₂ -one or more non-adjacent of-may be substituted by-O-or-NH-, k is an integer of 0 to 2,

in the formula (2-3), R ^3a Each independently represents a hydrogen atom or a monovalent group represented by the formula (P1-1) or (P1-2) ⁴ And R ⁵ Each independently is a hydrogen atom or a fluorine atom, R ⁴ And R ⁵ Not being simultaneously hydrogen atoms, R ^3c Each independently is a hydrogen atom, a methyl group, a methoxy group, a trifluoromethyl group, a fluorine atom, X ₁ Is an alkylene group having 1 to 12 carbon atoms, and when the carbon number of the alkylene group is 2 or more, - (CH) of the alkylene group ₂ ) ₂ -one or more non-adjacent of-may be substituted by-O-or-NH-, m is an integer of 0 to 2,

in the formulae (P1-1) and (P1-2), R ^6a 、R ^7a And R ^8a Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkanoyl group, or a substituted or unsubstituted alkoxycarbonyl group, R ^6a 、R ^7a And R ^8a May be the same as or different from each other, and represents a bonding position on the benzene ring in the formula (2-1), the formula (2-2) or the formula (2-3),

in the formula (2-1), the formula (2-2) or the formula (2-3), a group whose bonding position is not fixed to any one of carbon atoms constituting a ring means that the bonding position on the ring is arbitrary.

5. The liquid crystal aligning agent for photoalignment according to claim 1 or 2, wherein the compound having a photoreactive structure is at least one compound represented by formula (3);

in the formula (3), R ¹ And R ² Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, R ¹ And R ² May be a methylene group which may be substituted, X independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and n independently represents an integer of 0 to 4.

6. The liquid crystal aligning agent according to claim 1 or 2, further comprising an additive.

7. The liquid crystal aligning agent according to claim 6, wherein the additive is at least one selected from the group consisting of oxazoline compounds and epoxy compounds.

8. A liquid crystal alignment film formed from the liquid crystal aligning agent for photoalignment described in any one of claims 1 to 7.

9. A liquid crystal cell having the liquid crystal alignment film according to claim 8.

10. A method for manufacturing a liquid crystal alignment film, comprising: a step of applying the liquid crystal aligning agent for photoalignment according to any one of claims 1 to 7 to a substrate; and irradiating the coating film with polarized ultraviolet rays.