WO2022014470A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal alignment film that can quickly eliminate after images and can provide a high display quality in a high definition liquid crystal display.　This liquid crystal alignment agent contains at least one polymer (A) selected from the group consisting of polyimide precursors obtained by using a diamine component including a diamine represented by formula (1a) and a diamine represented by formula (1b) and a tetracarboxylic acid derivative component including an aromatic tetracarboxylic dianhydride or a derivative thereof, and polyimides which are imidation products of said polyimide precursors. The liquid crystal alignment agent is characterized in that the diamine component includes 5-95 mol% of the diamine represented by formula (1a) with respect to 1 mol of the used diamine component. [Chem. 1] (Any hydrogen atom on the benzene rings may be substituted with a monovalent substituent.) [Chem. 2] (Y is as defined in the description.)

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element.

Conventionally, liquid crystal displays have been widely used as display units for personal computers, smartphones, mobile phones, television receivers, and the like. The liquid crystal display device is, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, and a liquid crystal alignment film that controls the orientation of liquid crystal molecules in the liquid crystal layer. , A thin film transistor (TFT) for switching an electric signal supplied to a pixel electrode is provided. As the driving method of the liquid crystal molecule, a vertical electric field method such as a TN method and a VA method, and a horizontal electric field method such as an IPS method and an FFS (fringe field switching) method are known.

Currently, the most widely used liquid crystal alignment film in industry is a polymer film formed on an electrode substrate, which is represented by a polyamic acid and / or a polyimide obtained by imidizing the polyamic acid. It is manufactured by performing a so-called rubbing process of rubbing in one direction with a cloth such as. The rubbing process is a simple and highly productive industrially useful method. However, with the increase in performance, definition, and size of liquid crystal display elements, scratches on the surface of the alignment film generated by the rubbing process, dust generation, the effects of mechanical force and static electricity, and the in-plane alignment process Various problems such as non-uniformity of the above have been clarified. As an orientation treatment method instead of the rubbing treatment, a photo-alignment method for imparting a liquid crystal alignment ability by irradiating with polarized radiation is known. As the photoalignment method, a method using a photoisomerization reaction, a method using a photocrosslinking reaction, a method using a photodecomposition reaction, and the like have been proposed (for example, Non-Patent Document 1, Patent Document 1, and Patent Document 2). reference). Furthermore, a technique for increasing the response speed of a liquid crystal by adding a photopolymerizable compound to the liquid crystal composition in advance and irradiating the liquid crystal cell with ultraviolet rays while applying a voltage (PSA (Polymer Sutained Selected) method element). A production process using (see, for example, Patent Document 3) is also known.

One of the characteristics required for the liquid crystal alignment film is high display quality with few display defects of the liquid crystal display element. In particular, in mobile phones and tablet-type terminals, which have been rapidly improving in definition recently, high display quality is regarded as important, and there are specifications for display defects such as so-called "afterimage phenomenon" or simply "afterimage". It is getting tougher and harder. For example, it is required to realize a liquid crystal alignment film having a property of quickly disappearing even if an afterimage is generated. In Patent Document 4, a specific diamine and a specific aromatic tetracarboxylic acid derivative are reacted in a predetermined amount. A liquid crystal alignment agent containing a polyimide precursor obtained by the above-mentioned is disclosed.

Japanese Patent Application Laid-Open No. 9-297313 International Publication No. 2016/152928 Japanese Patent Application Laid-Open No. 2003-307720 International Publication No. 2013/062115

However, the conventional liquid crystal alignment film did not have sufficient characteristics to quickly eliminate the afterimage. That is, the conventional liquid crystal alignment film exhibits sufficient characteristics as long as the environment in which it is used is limited, but in recent years, liquid crystal display devices have been used in a wide temperature range from extremely low temperature (-20 ° C) to high temperature. It is required that the characteristics can be fully exhibited. In addition, as the liquid crystal display device has become higher in definition, the visibility of the afterimage has become higher than in the past. From the above, there is a demand for a liquid crystal alignment film that eliminates afterimages more quickly than ever before.

Therefore, an object of the present invention is to provide a liquid crystal alignment film capable of quickly eliminating an afterimage and exhibiting high display quality in a high-definition liquid crystal display device. Further, it is also an object of the present invention to provide a liquid crystal alignment agent for obtaining the liquid crystal alignment film and a liquid crystal display element using the liquid crystal alignment film.

The present inventor has conducted diligent research to achieve the above problems, and as a result, a liquid crystal alignment agent containing a polymer obtained by using a specific amount of a specific diamine component and an aromatic tetracarboxylic acid dianhydride as essential components. We have found that the liquid crystal alignment film formed by using the above-mentioned is extremely effective for achieving the above object, and completed the present invention.

The present invention includes the following aspects.
Obtained using a diamine represented by the following formula (1a), a diamine component containing a diamine represented by the following formula (1b), and a tetracarboxylic acid derivative component containing an aromatic tetracarboxylic acid dianhydride or a derivative thereof. A liquid crystal aligning agent containing at least one polymer (A) selected from the group consisting of a polyimide precursor to be obtained and a polyimide which is an imidized product of the polyimide precursor, wherein the diamine component is the formula (1a). ) Is contained in an amount of 5 to 95 mol% with respect to 1 mol of the diamine component used.

(Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent.)

(Y represents a divalent organic group having at least one structure selected from the group consisting of a nitrogen atom-containing heterocycle which may be substituted and an amine structure represented by the following formula (b) in the molecule. )

(R represents a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or a group having —O— between carbon-carbon bonds of the chain hydrocarbon group having 1 to 10 carbon atoms. Any hydrogen atom can be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, and fluorine. It may be substituted with at least one selected from the group consisting of atoms.)

According to the present invention, it is possible to provide a liquid crystal alignment film capable of quickly eliminating an afterimage and exhibiting high display quality in a high-definition liquid crystal display device. Further, according to the present invention, it is possible to provide a liquid crystal alignment agent for obtaining the liquid crystal alignment film and a liquid crystal display element using the liquid crystal alignment film.
The mechanism by which the above effects of the present invention are obtained is not always clear, but it is considered that the following is one of the causes.
That is, it is considered that the electron mobility is improved and the relaxation rate is improved by directly connecting the phenyl group or nitrogen atom-containing heterocycle and the urea group to expand the conjugated system.

In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Also, in the present specification, Boc represents a tert-butoxycarbonyl group.

Hereinafter, a liquid crystal alignment agent containing a polymer obtained by using a specific amount of a specific diamine component and an aromatic tetracarboxylic acid dianhydride as essential components, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal alignment film. The liquid crystal display element having the liquid crystal alignment film will be described in detail, but the description of the constituent requirements described below is an example as an embodiment of the present invention, and is not specified in these contents.

(Liquid crystal alignment agent)
The liquid crystal alignment agent of the present invention contains the polymer (A).
Preferred embodiments of the liquid crystal alignment agent of the present invention include a liquid crystal alignment agent containing a polymer (A) and an organic solvent.
Further, the liquid crystal alignment agent of the present invention can also contain a polymer other than the polymer (A) (for example, the polymer (B) described later).

<Polymer (A)>
The polymer (A) is a diamine represented by the above formula (1a) (hereinafter, also referred to as a specific diamine (1a)) and a diamine represented by the above formula (1b) (hereinafter, also referred to as a specific diamine (1b)). A group consisting of a polyimide precursor obtained by using a diamine component containing () and a tetracarboxylic acid derivative component containing an aromatic tetracarboxylic acid dianhydride or a derivative thereof, and a polyimide which is an imidized product of the polyimide precursor. It contains at least one polymer (A) selected from the above, and contains 5 to 95 mol% of the diamine represented by the formula (1a) with respect to 1 mol of the diamine component used.
Specific examples of such a polymer include a polyimide precursor having an imide precursor structure such as polyamic acid and a polyamic acid ester, and polyimide which is an imidized product of the polyimide precursor.

<< Specific diamine (1a) >>
The specific diamine (1a) used in the present invention is represented by the following formula (1a).

(Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent.)

Examples of the monovalent substituent on the benzene ring include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms. Fluoroalkyl group, fluoroalkenyl group having 2 to 10 carbon atoms, fluoroalkoxy group having 1 to 10 carbon atoms, carboxyl group, alkyloxycarbonyl group having 1 to 10 carbon atoms, cyano group, nitro group and the like.

From the viewpoint of efficiently obtaining the effect of the present invention, preferred specific examples of the specific diamine (1a) include diamines represented by the following formulas (1a-1) to (1a-3). Not limited.

<< Specific diamine (1b) >>
The specific diamine (1b) used in the present invention is represented by the following formula (1b).

(Y represents a divalent organic group having at least one structure selected from the group consisting of a nitrogen atom-containing heterocycle which may be substituted and an amine structure represented by the following formula (b) in the molecule. )

(R represents a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or a group having —O— between carbon-carbon bonds of the chain hydrocarbon group having 1 to 10 carbon atoms. Any hydrogen atom can be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, and fluorine. It may be substituted with at least one selected from the group consisting of atoms.)

Examples of the nitrogen atom-containing heterocycle include pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indol, benzoimidazole, purine, quinoline, isoquinoline, naphthylidine, quinoxaline, phthalazine, triazine, carbazole, and acridin. Examples thereof include piperidine, piperazine, pyrridine, hexamethyleneimine and the like. Of these, pyrrole, pyridine, pyrimidine, pyrazine, benzimidazole, piperidine, piperazine, quinoline, carbazole or acridine are preferable. Any hydrogen atom on the nitrogen atom-containing heterocycle has an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, and fluorine having 1 to 3 carbon atoms. It may be substituted with at least one selected from the group consisting of an atom-containing alkoxy group and a fluorine atom.

Examples of the chain hydrocarbon group having 1 to 10 carbon atoms in R include an alkyl group such as a methyl group and an ethyl group, an alkenyl group such as a vinyl group, and an alkynyl group such as an ethynyl group. Of these, an alkyl group having 1 to 10 carbon atoms is preferable, and a methyl group and an ethyl group are more preferable.

From the viewpoint of efficiently obtaining the effects of the present invention, the above Y is preferably a divalent organic group represented by the following formulas (y1) to (y8). When the Y contains an amine structure represented by the formula (b), the structures represented by the following formulas (y5) to (y8) are preferable.

(R is synonymous with the above formula (b). Q represents a nitrogen atom-containing heterocycle which may be substituted. L is a single bond, —O—, —C (= O, respectively) independently of each other. )-, -NR- (R is synonymous with the above formula (b)), -NRCO- (R is synonymous with the above formula (b)), -CH ₂ -,-(CH ₂ ) _n -(N represents an integer of 2 to 12), or at least a part of -CH _{2- of the- (CH 2} ) _n- is -O-, -C (= O)-, -NR- (R). Represents a group replaced with the above formula (b)) or -NRCO- (R is synonymous with the above formula (b)). L'is an independent single bond, respectively. _{-C (= O) -, -} CH 2 -, - (CH 2) n - (. n represents an integer of 2 to 12), or the - _{(CH 2) n} - -CH ₂ - of at least one Represents a group in which the part is replaced with -O- or -C (= O)-. Any hydrogen atom on the benzene ring has an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a carbon number of carbon atoms. It may be substituted with at least one selected from the group consisting of 1 to 3 fluorine atom-containing alkyl groups, 1 to 3 carbon atoms-containing alkoxy groups and fluorine atoms. L, Q, R and L'are substituted. When there are a plurality of them in one formula, they may be the same or different independently.)

From the viewpoint of efficiently obtaining the effect of the present invention, preferred specific examples of the specific diamine (1b) include diamines represented by the following formulas (1b-1) to (1b-20) and the following formula (1b'-). 1)-Diamine represented by (1b'-11), 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole and N-methyl-3,6 -Includes, but is not limited to, diaminocarbazole.

<< Diamine component >>
The diamine component for obtaining the polymer (A) contains 5 to 95 mol% of the diamine represented by the specific diamine (1a) with respect to 1 mol of the diamine component used, and contains the specific diamine (1b). include. The specific diamine (1a) and the specific diamine (1b) may each be composed of one kind of diamine or two kinds of diamines.
The ratio of the diamine represented by the specific diamine (1a) in the diamine component for obtaining the polymer (A) is more preferably 10 to 90 mol% with respect to 1 mol of the diamine component used. It is more preferable to contain 80 mol%. The ratio of the specific diamine (1b) in the diamine component for obtaining the polymer (A) is preferably 5 to 95 mol% and 10 to 90 mol% with respect to 1 mol of the diamine component used. It is more preferable, and it is further preferable to contain 20 to 90 mol%.
As the diamine component for obtaining the polymer (A), other diamines other than the above-mentioned specific diamine (1a) and specific diamine (1b) may be used. Examples of other diamines include the following diamines.
Diamines having photoorienting groups such as 4,4'-diaminoazobenzene and _{diamines represented by the following formulas (d T} -1) to (d _T -3); 2,4-diaminophenol, 3,5-diamino Phenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid and: Diamines having a carboxy group such as the diamine compounds represented by the formulas (3b-1) to (3b-4); 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4- (2- (Methylamino) ethyl) aniline, 4,4'-diaminobenzophenone, 1,4-bis (4-aminobenzyl) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3 -Bis (4-aminophenoxy) benzene, 4,4'-diaminodiphenyl ether, 1- (4-aminophenyl) -1,3,3-trimethyl-1H-indan-5-amine, 1- (4-aminophenyl) ) -2,3-Dihydro-1,3,3-trimethyl-1H-inden-6-amine; a diamine having a urea bond such as a diamine represented by the following formulas (h-1) to (h-3); Diamines having an amide bond represented by the following formulas (h-4) to (h-6); 2- (2,4-diaminophenoxy) ethyl methacrylate and 2,4-diamino-N, N-diallylaniline and the like. Diamine having a photopolymerizable group at the end; a diamine having a siloxane bond such as 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; Diamine having an oxazoline structure; a diamine represented by the following formula (2) or formula (2i), or the like.

(In the formula ^{(3b-1), A} 1 is a single _{bond, -CH 2 -, - C 2} H 4 -, - C (CH 3) 2 -, - CF 2 -, - C (CF 3) 2 -, -O-, -CO-, _{-NH-, -N (CH 3} )-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO-, -OCO-, -CON ( CH ₃ )-or -N (CH ₃ ) CO-, m1 and m2 independently represent an integer of 0 to 4, and m1 + m2 represent an integer of 1 to 4. Equation (3b-2). Medium, m3 and m4 each independently represent an integer of 1 to 5. In the formula (3b-3), A ² represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents 1 to 5. . of an integer expression in (3b-4), ^{a 3} and ^{a 4} are each independently a single _{bond, -CH 2 -, - C 2} H 4 -, - C (CH 3) 2 -, - CF _2- , -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO -, - OCO -, - CON (CH 3) - or -N _(CH 3) CO- represents, m6 is an integer of 1-4).

(Y ₂ represents a divalent organic group represented by the following formula (O). Two Rs independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Two Y _2i are each. Independently represents a divalent organic group represented by the following formula (O').)

(Ar represents a divalent benzene ring, biphenyl structure, or naphthalene ring. The two Ars may be the same or different, and any hydrogen atom of the benzene ring, biphenyl structure, or naphthalene ring is a monovalent substitution. It may be substituted with a group. P is an integer of 0 or 1. Q ₂ is − (CH ₂ ) _n − (n is an integer of 2 to 18), or the − (CH ₂ ) _n. -Represents a group in which at least a part of -CH _2- is replaced with either -O-, -C (= O)-or -OC (= O)-. * Represents a bond.)

(Ar'represents a divalent benzene ring or biphenyl structure. Two Ar's may be the same or different, and any hydrogen atom of the benzene ring or biphenyl structure is substituted with a monovalent substituent. good .p 'is a is .Q ₂ 0 or the integer _1' even if the - _{(CH 2)} n - (. n is an integer of 2 to 18), or the - _{(CH 2) n} - of Represents a group in which at least a part of -CH _2- is replaced with either -O-, -C (= O)-or -OC (= O)-. * Represents a bond.)

Examples of the substituent of the benzene ring, the biphenyl structure or the naphthalene ring in the above formulas (O) and (O') include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and carbon. An alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkalkoxy group having 1 to 10 carbon atoms, a carboxyl group, a hydroxy group, and 1 to 10 carbon atoms. Examples thereof include an alkyloxycarbonyl group, a cyano group and a nitro group.

The divalent organic group represented by the above formula (O) is preferably a divalent organic group represented by the following formulas (o-1) to (o-16) from the viewpoint of enhancing the liquid crystal orientation. In the formula, * represents a bond.

(In the equation (o-14), the two m each independently represent an integer of 1 to 3.)

Further, the divalent organic group represented by the above formula (O') is a divalent organic group represented by the above formulas (o-7) to (o-16) from the viewpoint of enhancing the liquid crystal orientation. preferable.

<< Tetracarboxylic acid derivative component >>
When the above polymer (A) is produced, the tetracarboxylic acid derivative component to be reacted with the diamine component is not only tetracarboxylic acid dianhydride, but also tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester. Derivatives of tetracarboxylic acid dianhydride such as dihalide can also be used. As the tetracarboxylic acid derivative component, one kind of tetracarboxylic dianhydride or a derivative thereof may be used alone, or two or more kinds thereof may be used in combination.
The tetracarboxylic acid derivative component for obtaining the polymer (A) contains an aromatic tetracarboxylic acid dianhydride or a derivative thereof, and comprises one kind of aromatic tetracarboxylic acid dianhydride or a derivative thereof. It may be composed of two or more kinds of aromatic tetracarboxylic acid dianhydrides or derivatives thereof.
Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to the aromatic ring. However, it does not have to be composed only of an aromatic ring structure, and may have a chain hydrocarbon structure or an alicyclic structure as a part thereof.
Examples of the aromatic tetracarboxylic dianhydride or a derivative thereof include an aromatic tetracarboxylic dianhydride represented by the following formula (Ta) or a derivative thereof.

(Xa represents a structure selected from the group consisting of the following formulas (a-1) to (a-9).)

(J and k are integers of 0 or 1, and A ₁ and A ₂ are independent, single bond, -O-, -CO-, -COO-, phenylene, -SO _{2-, or-, respectively.} NRCO- (R represents. a hydrogen atom or a methyl group) in representing the. * represents a bond that binds to the acid anhydride group. formula (a-2), 2 two a ₂ is be the same or different good.)

Preferred specific examples of the above formulas (a-1) and (a-2) include the following formulas (a-10) to (a-25). In addition, "*" in the formula represents a bond that binds to an acid anhydride group.

The ratio of the aromatic tetracarboxylic dianhydride or its derivative represented by the above formula (Ta) is 10 to 10 to 1 mol of the total tetracarboxylic dianhydride component used in the synthesis of the polymer (A). 100 mol% is preferable, 20 to 100 mol% is more preferable, and 50 to 100 mol% is further preferable.
The tetracarboxylic acid dianhydride and its derivative used in the production of the polymer (A) are the aromatic tetracarboxylic acid dianhydride represented by the above formula (Ta) or a tetracarboxylic acid dianhydride other than the derivative thereof. The derivative (hereinafter, other tetracarboxylic acid dianhydride or a derivative thereof) may be contained. Examples of other tetracarboxylic dianhydrides or derivatives thereof include acyclic aliphatic or alicyclic tetracarboxylic dianhydrides or derivatives thereof.

Here, the acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it does not have to be composed only of a chain hydrocarbon structure, and may have a heteroatom such as an alicyclic structure, an aromatic ring structure, or an oxygen atom as a part thereof. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to the alicyclic structure. However, none of these four carboxyl groups are bonded to the aromatic ring. Further, it does not have to be composed only of an alicyclic structure, and may have a chain hydrocarbon structure or an aromatic ring structure as a part thereof.

Preferred examples of the other tetracarboxylic dianhydrides or derivatives thereof include tetracarboxylic dianhydrides represented by the following formulas (T) and the following formulas (2T) or derivatives thereof. The above-mentioned other tetracarboxylic dianhydrides or derivatives thereof may be used alone or in combination of two or more. From the viewpoint of liquid crystal orientation, acyclic aliphatic or alicyclic tetracarboxylic dianhydride represented by the following formula (T) is preferable.

(X represents a structure selected from the group consisting of the following formulas (x-1) to (x-11). X ₂ is selected from the group consisting of the following formulas (t-1) to (t-19). Represents the structure.)

(R ¹ to R ⁴ each independently contain a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, and a fluorine atom. It represents a monovalent organic group or a phenyl group having 1 to 6 carbon atoms. R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. * Is a bond that binds to an acid anhydride group. show.)

(* Represents a bond that binds to an acid anhydride group. In the formula (t-1), the six Rs are independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, and a carbon number of carbon atoms. An alkenyl group having 2 to 6, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. From the viewpoint of liquid crystal orientation, R is hydrogen. An atom, a halogen atom, a methyl group, or an ethyl group is preferable, and a hydrogen atom or a methyl group is more preferable.)

As a preferable specific example of the alicyclic tetracarboxylic dianhydride represented by the above formula (T) or a derivative thereof, it is more preferable that X is the above formulas (x-1) to (x-6). ..

The above formula (x-1) is preferably selected from the group consisting of the following formulas (x1-1) to (x1-6).

(* Represents a bond that binds to an acid anhydride group.)
However, the tetracarboxylic acid derivative component for obtaining the polymer (A) is represented by the above formula (T), wherein X represents a structure selected from the group consisting of the above formulas (x-1) to (x-7). It does not have to contain the alicyclic tetracarboxylic dianhydride.

<Polymer (B)>
The liquid crystal aligning agent of the present invention is selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component and a diamine component and a polyimide which is an imidized product of the polyimide precursor, from the viewpoint of enhancing the liquid crystal orientation. The polymer (B) (however, excluding the polymer (A)) may be contained. Specific examples of such a polymer include a polyimide precursor obtained by using a tetracarboxylic acid derivative component and a diamine component not containing the specific diamine (1a), and a polyimide which is an imidized product of the polyimide precursor. Examples thereof include polymers selected from the group consisting of.
Specific examples of the polyimide precursor include polyamic acid and polyamic acid ester.
As the polymer (B), one type may be used alone, or two or more types may be used in combination.

Examples of the tetracarboxylic dianhydride component for obtaining the polymer (B) include acyclic aliphatic tetocarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride or derivatives thereof. Can be mentioned. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride, the alicyclic tetracarboxylic dianhydride, and the aromatic tetocarboxylic dianhydride include the tetracarboxylic dianhydride exemplified in the polymer (A). Can be mentioned. Among them, the preferred tetcarboxylic acid derivative component is an aromatic tetracarboxylic acid dianhydride represented by the above formula (Ta) or a derivative thereof, an alicyclic tetracarboxylic acid dianhydride represented by the above formula (T) or a derivative thereof. Derivatives (hereinafter, these are also collectively referred to as a specific tetracarboxylic acid derivative component (b)) are preferable. As the tetracarboxylic acid derivative component, one kind of tetracarboxylic dianhydride or a derivative thereof may be used alone, or two or more kinds thereof may be used in combination.

The ratio of the specific tetracarboxylic acid derivative component (b) used is preferably 1 to 100 mol% with respect to 1 mol of the total tetracarboxylic acid derivative component used in the synthesis of the polymer (B), preferably 5 to 100. More preferably mol%, more preferably 10-100 mol%.

Examples of the diamine component for obtaining the polymer (B) include the diamine exemplified in the polymer (A). Among them, from the viewpoint of enhancing the liquid crystal orientation, diamines having photoalignant groups such as _{4,4'-diaminoazobenzene and diamines represented by the above formulas (d T} -1) to (d _{T -3); 3,} 3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4- (2- (methylamino) ethyl) aniline, 4,4'-diaminobenzophenone, 1,4-bis (4) -Aminobenzyl) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4'-diaminodiphenyl ether; the above formulas (h-1) to (h). A diamine having a urea bond such as a diamine represented by -3); a diamine having an amide bond represented by the above formulas (h-4) to (h-6); 2- (2,4-diaminophenoxy) methacrylate. ) Diamine having a photopolymerizable group such as ethyl and 2,4-diamino-N, N-diallylaniline at the end; Diamine having a siloxane bond such as 1,3-bis (3-aminopropyl) -tetramethyldisiloxane A diamine having an oxazoline structure such as the above formulas (Ox-1) to (Ox-2); a diamine represented by the above formula (2) or the above formula (2i) is preferable.
The preferred embodiment of the diamine represented by the above formula (2) or the above formula (2i) is the same as the above.

In the diamine component for obtaining the polymer (B), two or more kinds of diamines represented by the above formula (2) may be used, for example, Y ₂ is the above formulas (o-1) to (o-14). The diamine of the above formula (2) which is a divalent organic group represented by the above formula, and the above formula (the above formula) _{where Y 2} is a divalent organic group represented by the above formulas (o-15) to (o-16). It may be a combination with the diamine of 2).

Preferred specific examples of the diamine represented by the above formula (2i) include compounds represented by the following formulas (2i-1) to (2i-5).

(In the equation (2i-1) and the equation (2i-2), the two ns independently represent an integer of 1 to 6. In the equation (2i-3), the two ns are independent of each other. Represents an integer of 2 to 6)

From the viewpoint of enhancing the liquid crystal orientation, the polymer (B) is 4,4'-diaminoazobenzene, _{a diamine represented by the above formulas (d T} -1) to (d _T -3), and 3,3'-diamino. Diphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4- (2- (methylamino) ethyl) aniline, 4,4'-diaminobenzophenone, 1,4-bis (4-aminobenzyl) Benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4'-diaminodiphenyl ether, with the above formulas (h-1) to (h-3). Select from the group consisting of the diamine represented, the diamine represented by the above formulas (h-4) to (h-6), the diamine represented by the above formula (2) and the diamine represented by the above formula (2i). At least one diamine may be used in an amount of 1 to 95 mol%, 30 to 95 mol%, or 40 to 90 mol% with respect to 1 mol of the diamine component used for the synthesis of the polymer (B). You may use it.

At least one of the polymer (A) and the polymer (B) has a group "-N (D)-(D is a carbamate-based protecting group) in the molecule from the viewpoint of increasing the voltage holding ratio of the obtained liquid crystal orientation display element. It represents.) ”. A polymer having the group "-N (D)-(D represents a carbamate-based protecting group)" is a single amount having a group "-N (D)-(D represents a carbamate-based protecting group)". Obtained by a method using a body, for example, a diamine having a group "-N (D)-(D represents a carbamate-based protecting group)" as at least a part of a raw material, or a method using a terminal encapsulant described later. Can be done. Examples of the carbamate-based protecting group include a tert-butoxycarbonyl group and a 9-fluorenylmethoxycarbonyl group.

The diamine having the group "-N (D)-(D represents a carbamate-based protecting group)" is more preferably having at least one aromatic group such as a benzene ring. More preferably, the residue excluding the group "(D)" is a diamine having 6 to 30 carbon atoms. Specific examples of the diamine having the group "-N (D)-(D represents a carbamate-based protecting group)" include compounds represented by the following formulas (5-1) to (5-10). Can be mentioned.

(Boc represents a tert-butoxycarbonyl group.)

The ratio of the diamine having the group "-N (D)-(D represents a carbamate-based protecting group)" is the diamine component used in the synthesis of the polymer from the viewpoint of increasing the voltage retention rate of the liquid crystal display element. 1 mol% or more is preferable with respect to 1 mol, and 2 mol% or more is more preferable. The usage ratio is preferably 50 mol% or less, more preferably 40 mol% or less, still more preferably 35 mol% or less.

From the viewpoint of efficiently obtaining the effects of the present invention, the content ratio of the polymer (A) to the polymer (B) is 10/90 in terms of the mass ratio of [polymer (A)] / [polymer (B)]. It may be ~ 90/10, 20/80 to 90/10, or 20/80 to 80/20.

<Method for producing polymer (A) and polymer (B)>
The polymer (A) or (B) is produced by reacting the diamine component and the tetracarboxylic acid derivative component in a solvent (condensation). When a part of the polymer (A) or (B) contains an amic acid structure, for example, a polymer having an amic acid structure (polyamic acid) by reacting a tetracarboxylic acid dianhydride component with a diamine component. Is obtained. The solvent is not particularly limited as long as it dissolves the produced polymer.
Specific examples of the above solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl. -2-Imidazolidinone can be mentioned. When the polymer has high solvent solubility, it is represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formulas [D-1] to [D-3]. A solvent can be used.

(In the formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, and in the formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and the formula [D-3]. ], D ³ represents an alkyl group having 1 to 4 carbon atoms.)

These solvents may be used alone or in combination. Further, even if the solvent does not dissolve the polymer, it may be mixed with the above solvent and used as long as the produced polymer does not precipitate.
When the diamine component and the tetracarboxylic acid derivative component are reacted in a solvent, the reaction can be carried out at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial reaction can be carried out at a high concentration and then the solvent can be added.
In the reaction, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid derivative component is preferably 0.8 to 1.2. Similar to a normal polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weights of the polymer (A) and the polymer (B) produced.

The polymer containing an amic acid ester structure (polyamic acid ester) is, for example, [I] a method of reacting the polyamic acid obtained by the above method with an esterifying agent, [II] a tetracarboxylic acid diester and a diamine. It can be obtained by a known method such as a method of reacting, a method of reacting a tetracarboxylic acid diester dihalide with a diamine, and the like.

The imidized product in the polymer (A) or (B) contained in the liquid crystal alignment agent of the present invention is obtained by ring-closing the polymer obtained above. The ring closure rate (also referred to as imidization rate) of the functional group of the amic acid group or its derivative does not necessarily have to be 100%, and the imidized product can be arbitrarily adjusted according to the intended use and purpose.
From the viewpoint of enhancing the liquid crystal orientation, the imidization ratio of the polymer (B) is preferably 20 to 100%, preferably 50 to 95%, and even more preferably 60 to 90%.

Examples of the method for obtaining an imidized product include thermal imidization in which the polymer solution obtained in the above reaction is heated as it is, or catalytic imidization in which a catalyst is added to the polymer solution. The temperature for thermal imidization in the solution is preferably 100 to 400 ° C, more preferably 120 to 250 ° C, and it is preferable to remove the water produced by the imidization reaction from the system.

The catalyst imidization is carried out by adding a basic catalyst and an acid anhydride to a solution of the polymer obtained by the reaction, and stirring the mixture at preferably −20 to 250 ° C., more preferably 0 to 180 ° C. be able to. The amount of the basic catalyst is preferably 0.5 to 30 mol times, more preferably 2 to 20 mol times, and the amount of acid anhydride is preferably 1 to 50 mol times, more than the amic acid group. It is preferably 3 to 30 mol times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, and tributylamine trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like, and among them, acetic anhydride is preferable because it facilitates purification after the reaction is completed. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, the reaction temperature, and the reaction time.

When recovering the produced imidized product from the above-mentioned imidization reaction solution, the reaction solution may be added to a solvent for precipitation. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellsolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water and the like. The polymer put into a solvent and precipitated can be collected by filtration and then dried at room temperature or by heating under normal pressure or reduced pressure. Further, by repeating the operation of re-dissolving the polymer recovered by precipitation in a solvent and re-precipitating and recovering it 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent at this time include alcohols, ketones, hydrocarbons, and the like, and it is preferable to use three or more kinds of solvents selected from these, because the purification efficiency is further improved.

<Solution viscosity / molecular weight of polymer>
The polymer (A) or (B) used in the present invention preferably has a solution viscosity of, for example, 10 to 1000 mPa · s when it is used as a solution having a concentration of 10 to 15% by mass from the viewpoint of workability. However, it is not particularly limited. The solution viscosity (mPa · s) of the polymer is a polymer having a concentration of 10 to 15% by mass prepared by using a good solvent of the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The values of the solution were measured at 25 ° C. using an E-type rotational viscometer.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polymer (A) or (B) is preferably 1,000 to 500,000, more preferably 2,. It is 000 to 500,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. Within such a molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.

<Terminal sealant>
When synthesizing the polymer (A) and the polymer (B) in the present invention, an end-sealed polymer is prepared by using an appropriate end-sealing agent together with the tetracarboxylic acid derivative component and the diamine component as described above. It may be synthesized. The end-sealed polymer has the effects of improving the film hardness of the liquid crystal alignment film obtained by the coating film and improving the adhesion characteristics between the sealant and the liquid crystal alignment film.
Examples of the terminal of the polymer (A) and the polymer (B) in the present invention include an amino group, a carboxy group, an acid anhydride group or a derivative thereof. Amino groups, carboxy groups, acid anhydride groups or derivatives thereof can be obtained by a usual condensation reaction or by sealing the ends with the following terminal encapsulants, wherein the derivatives are, for example, , Can also be obtained in the same manner using the following terminal encapsulants.

Examples of the terminal encapsulant include acetic anhydride, maleic anhydride, nagic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-( (3-Trimethoxysilyl) propyl) -3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynylphthalic anhydride, etc. Acid Anhydride; Dicarbonate diester compounds such as di-tert-butyl dicarbonate, diallyl dicarbonate; Chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, nicotinic acid chloride; aniline, 2-aminophenol, 3-aminophenol, 4-Aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, Monoamine compounds such as n-heptylamine and n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenylisocyanate and naphthylisocyanate can be mentioned.

The ratio of the terminal encapsulant to be used is preferably 0.01 to 20 mol parts, more preferably 0.01 to 10 mol parts, based on 100 mol parts of the total diamine component used.

<Other components in liquid crystal alignment agent>
The liquid crystal alignment agent of the present invention contains a polymer (A) and, if necessary, a polymer (B). The liquid crystal alignment agent of the present invention may contain other polymers in addition to the polymer (A) and the polymer (B). Examples of other types of polymers include polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polyacetal, polystyrene or its derivatives, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates and the like.

The liquid crystal alignment agent is used for producing a liquid crystal alignment film, and takes the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal alignment agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent. At that time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed by setting the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 1% by mass or more is preferable, and from the viewpoint of storage stability of the solution, 10% by mass or less is preferable. A particularly preferable concentration of the polymer is 2 to 8% by mass.
The content of the polymer (A) in the liquid crystal alignment agent can be appropriately changed depending on the application method of the liquid crystal alignment agent and the film thickness of the target liquid crystal alignment film, but it may be 2 to 10% by mass. It is preferable, and particularly preferably 3 to 7% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, and γ-butyrolactone. , Γ-Valerolactone, 1,3-dimethyl-2-imidazolidinone, methylethylketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropaneamide, N- (n-propyl) -2-pyrrolidone, N-isopropyl-2-pyrrolidone, N- (n-butyl) -2-pyrrolidone, N- (tert-butyl) -2-pyrrolidone, N- (n-pentyl) ) -2-Pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (collectively "good solvent") Also known as). Of these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide or γ-butyrolactone are preferable. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass based on the total amount of the solvent contained in the liquid crystal alignment agent.

Further, the organic solvent contained in the liquid crystal alignment agent is a mixture in which a solvent (also referred to as a poor solvent) for improving the coatability when applying the liquid crystal alignment agent and the surface smoothness of the coating film is used in combination with the above solvent. The use of solvent is preferred. Specific examples of the poor solvent used in combination are described below, but the present invention is not limited thereto. The content of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass, based on the total amount of the solvent contained in the liquid crystal alignment agent. The type and content of the poor solvent are appropriately selected according to the liquid crystal alignment agent coating device, coating conditions, coating environment, and the like.

For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyetan, diethylene glycol dimethyl ether, diethylene glycol diethyl ether. , 4-Hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene Glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1- (2-butoxyethoxy) -2-propanol, 2- (2-butoxyethoxy) -1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol Monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate. , Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl Ketone (2,6-dimethyl-4-heptanone), etc.

Among them, diisobutylcarbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene. Glycol monobutyl ether acetate or diisobutyl ketone is preferred.

Preferred combinations of good and poor solvents include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, and N-methyl-2-. Pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2- Pyrrolidone and Propylene Glycol Diacetate, N, N-Dimethyllactoamide and Diisobutylketone, N-Methyl-2-pyrrolidone and Ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and Ethyl 3-ethoxypropionate, N- Methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether, N, N-dimethyllactoamide and ethylene glycol monobutyl ether, N, N-dimethyllactoamide and propylene glycol di Acetate, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether, N, N-dimethyllactoamide and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone. Diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2- Pentanone and Propylene Glycol Monobutyl Ether, N-Methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and Diisobutylketone, N-Methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone Dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone And Propylene Glycol Diacetate, γ-Buchirolactone and 4-Hydroxy-4-methyl-2-pentanone and Diisobutylketone, γ-Buchirolactone and 4-hydroxy-4-methyl-2-pentanone and Propylene Glycoldiacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylketone, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2- Pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutylcarbinol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether. Examples thereof include diisobutylketone, N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutylketone, N-ethyl-2-pyrrolidone and N, N-dimethyllactamide and diisobutylketone.

The liquid crystal alignment agent of the present invention may additionally contain a component other than the polymer component and the organic solvent (hereinafter, also referred to as an additive component). Such additive components include an adhesion aid for enhancing the adhesion between the liquid crystal alignment film and the substrate and the adhesion between the liquid crystal alignment film and the sealing agent, and a compound for increasing the strength of the liquid crystal alignment film (hereinafter,). (Also referred to as a crosslinkable compound), a dielectric for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film, a conductive substance, and the like can be mentioned.

As the crosslinkable compound, from the viewpoint of exhibiting good resistance to AC afterimage and improving film strength, an oxylanyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, and a meldrum. A compound having at least one group selected from the group consisting of a group containing an acid structure, a cyclocarbonate group, a group represented by the following formula (d) and a group represented by the following formula (d1), or a compound having the following formula ( It may be a compound selected from the compounds represented by e).

(R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or "* -CH _2- OH". * Indicates a bond. R is 1 carbon atom. Represents an alkyl group of up to 6; an alkenyl group of 2 to 6 carbon atoms, or an alkynyl group of 2 to 6 carbon atoms. Z represents a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, and an alkenyl group having 2 to 6 carbon atoms. , Or an alkynyl group having 2 to 6 carbon atoms. A represents a (m + n) valent organic group having an aromatic ring. R'represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. M represents 1 Represents an integer of ~ 6, and n represents an integer of 0 to 4.)

Specific examples of the compound having an oxylanyl group include the compound described in paragraph [0037] of JP-A-10-338880 and the compound having a triazine ring as a skeleton described in International Publication No. 2017/170483. Examples thereof include compounds having more than one oxylanyl group. Of these, N, N, N', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetra Nitrogen atoms such as glycidyl-4, 4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-p-phenylenediamine, compounds represented by the following formulas (r-1) to (r-3). It may be a compound containing.

Specific examples of the compound having an oxetanyl group include the compounds having two or more oxetanyl groups described in paragraphs [0170] to [0175] of International Publication No. 2011/132751.

Specific examples of the compound having a protected isocyanate group include the compounds having two or more protected isocyanate groups described in paragraphs [0046] to [0047] of Japanese Patent Application Laid-Open No. 2014-224978, International Publication No. 2015/141598. The compounds having three or more protected isocyanate groups described in paragraphs [0119] to [0120] of the above are mentioned, and the compounds represented by the following formulas (bi-1) to (bi-3) may be used. ..

Specific examples of the compound having a protected isothiocyanate group include the compounds having two or more protected isothiocyanate groups described in Japanese Patent Application Laid-Open No. 2016-2000798.

Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline structures described in paragraph [0115] of Japanese Patent Application Laid-Open No. 2007-286597.

Specific examples of the compound having a group containing a Meldrum's acid structure include the compound having two or more Meldrum's acid structures described in International Publication No. 2012/091088.

Specific examples of the compound having a cyclocarbonate group include the compound described in International Publication No. 2011/155577.

The R _2, an alkyl group having 1 to 3 carbon atoms R ₃ group represented by the above formula (d), a methyl group, an ethyl group, a propyl group.

Specific examples of the compound having a group represented by the above formula (d) include the above formula (d) described in International Publication No. 2015/072554 and paragraph [0058] of Japanese Patent Application Laid-Open No. 2016-118753. Examples thereof include compounds having two or more groups represented by (2) and compounds described in Japanese Patent Application Laid-Open No. 2016-209458, which are compounds represented by the following formulas (hd-1) to (hd-8). May be good.

Specific examples of the compound having a group represented by the above (d1) include the compounds described in International Publication No. 2019/142927, and more preferably the following formulas (hd1-1) to (hd1-4). It may be a compound represented.

Examples of the (m + n) -valent organic group having an aromatic ring in A of the above formula (e) include an (m + n) -valent aromatic hydrocarbon group having 6 to 30 carbon atoms and an aromatic hydrocarbon group having 6 to 30 carbon atoms. Examples thereof include (m + n) valent organic groups bonded directly or via a linking group, and (m + n) valent groups having an aromatic heterocycle. Examples of the aromatic hydrocarbon include benzene and naphthalene. Examples of the aromatic heterocycle include the aromatic heterocycle exemplified in the above nitrogen atom-containing structure. Examples of the linking group include an alkylene group having 1 to 10 carbon atoms, a group obtained by removing one hydrogen atom from the alkylene group, a divalent or trivalent cyclohexane ring, and the like. Any hydrogen atom of the alkylene group may be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. Examples of the alkyl group having 1 to 5 carbon atoms in R'of the above formula (e) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group and a tert-butyl group. Examples include the n-pentyl group. Specific examples include the compounds described in International Publication No. 2010/074269 and the compounds represented by the following formulas (e-1) to (e-10).

The above compound is an example of a crosslinkable compound, and is not limited thereto. For example, components other than the above disclosed in International Publication No. 2015/060357 on pages 53 [0105] to 55 [0116] can be mentioned. Further, two or more kinds of crosslinkable compounds may be combined.

The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, and the crosslinking reaction proceeds. In addition, from the viewpoint of exhibiting good resistance to AC afterimages, it is more preferably 1 to 15 parts by mass.

Examples of the adhesion aid include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N. -(2-Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N -Ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, vinyltrimethoxysilane, Vinyl triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane , 3-Glycydoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3- Examples thereof include silane coupling agents such as acryloxypropyltrimethoxysilane, tris (3-trimethoxysilylpropyl) isocyanurate, and 3-isocyandiapropyltriethoxysilane. When a silane coupling agent is used, it should be 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent from the viewpoint of exhibiting good resistance to AC afterimage. It is preferable, more preferably 0.1 to 20 parts by mass.

<Liquid crystal alignment film / liquid crystal display element>
The liquid crystal alignment film of the present invention is obtained from the above liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for a horizontally oriented type or a vertically oriented type (VA type) liquid crystal alignment film, and among them, a liquid crystal alignment suitable for a horizontally oriented type liquid crystal display element such as an IPS method or an FFS method. It is a membrane. The liquid crystal display element of the present invention includes the liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (4) or steps (1) to (2) and (4).

<Step (1): Step of applying the liquid crystal alignment agent on the substrate>
The liquid crystal alignment agent of the present invention is applied to one surface of a substrate provided with a patterned transparent conductive film by an appropriate coating method such as a roll coater method, a spin coating method, a printing method, or an inkjet method. Here, the substrate is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with the glass substrate and the silicon nitride substrate. Further, in the reflective liquid crystal display element, if only one side of the substrate is used, an opaque object such as a silicon wafer can be used, and in this case, a material that reflects light such as aluminum can also be used for the electrode. Further, in the case of manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb tooth shape, and a facing substrate not provided with an electrode. Is used.

Examples of the method of applying the liquid crystal alignment agent to the substrate to form a film include screen printing, offset printing, flexographic printing, inkjet method, spray method and the like. Among them, the coating and film forming methods by the inkjet method can be preferably used.

<Step (2): Step of firing the applied liquid crystal alignment agent>
The step (2) is a step of firing the liquid crystal alignment agent applied on the substrate to form a film. After applying the liquid crystal alignment agent on the substrate, the solvent is evaporated or the polyamic acid or polyamic acid ester is thermally imidized by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. Can be done. The drying and firing steps after applying the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and may be performed a plurality of times. The drying temperature can be, for example, 40 to 180 ° C. From the viewpoint of shortening the process, it may be carried out at 40 to 150 ° C. The drying time is not particularly limited, and examples thereof include 1 to 10 minutes or 1 to 5 minutes. When performing thermal imidization of a polyamic acid or a polyamic acid ester, a step of firing in a temperature range of, for example, 150 to 300 ° C. or 150 to 250 ° C. may be added after the above drying step. The firing time is not particularly limited, and examples thereof include a firing time of 5 to 40 minutes or 5 to 30 minutes.
If the film-like material after firing is too thin, the reliability of the liquid crystal display element may decrease, so 5 to 300 nm is preferable, and 10 to 200 nm is more preferable.

<Step (3): Orientation treatment on the film obtained in step (2)>
The step (3) is, in some cases, a step of orienting the film obtained in the step (2). That is, in a horizontally oriented liquid crystal display element such as an IPS system or an FFS system, an alignment ability imparting process is performed on the coating film. On the other hand, in a vertically oriented liquid crystal display element such as a VA method or a PSA mode, the formed coating film can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an alignment ability imparting treatment. Examples of the liquid crystal alignment film alignment treatment method include a rubbing treatment method and a photoalignment treatment method. As a photo-alignment treatment method, the surface of the film-like material is irradiated with radiation deflected in a certain direction, and in some cases, heat treatment is performed at a temperature of 150 to 250 ° C. to achieve liquid crystal orientation (liquid crystal alignment). There is a method of giving (also called Noh). As the radiation, ultraviolet rays having a wavelength of 100 to 800 nm or visible light can be used. Among them, ultraviolet rays having a wavelength of preferably 100 to 400 nm, more preferably 200 to 400 nm.

The irradiation amount of the above radiation is preferably ^{1 to 10,000 mJ / cm 2.} Of these, 100 to 5,000 mJ / cm ² is preferable. Further, when irradiating with radiation, in order to improve the liquid crystal orientation, the substrate having the film-like substance may be irradiated while being heated at 50 to 250 ° C. The liquid crystal alignment film thus produced can stably orient liquid crystal molecules in a certain direction.
Further, by the above method, the liquid crystal alignment film irradiated with polarized radiation can be contact-treated with a solvent, or the liquid crystal alignment film irradiated with radiation can be heat-treated.

The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition product generated from the film-like substance by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3-. Examples thereof include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like. Of these, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable, and water, 1-methoxy-2-propanol or ethyl lactate is more preferable from the viewpoint of versatility and solvent safety. The solvent may be used alone or in combination of two or more.

The temperature of the heat treatment for the coating film irradiated with the above radiation is more preferably 50 to 300 ° C, further preferably 120 to 250 ° C. The heat treatment time is preferably 1 to 30 minutes, respectively.

<Step (4): Step of manufacturing a liquid crystal cell>
Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and the liquid crystal is arranged between the two substrates arranged opposite to each other. Specifically, the following two methods can be mentioned. In the first method, first, two substrates are arranged facing each other through a gap (cell gap) so that the liquid crystal alignment films face each other. Next, the peripheral portions of the two substrates are bonded together using a sealant, and the liquid crystal composition is injected and filled into the surface of the substrate and the cell gap partitioned by the sealant to contact the film surface, and then the injection holes are sealed. Stop.

The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet light-curable sealant is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and the liquid crystal composition is further applied to a predetermined number of places on the liquid crystal alignment film surface. Is dropped. Then, the other substrate is bonded so that the liquid crystal alignment film faces each other, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant. Regardless of which method is used, it is desirable to remove the flow orientation during liquid crystal filling by further heating the liquid crystal composition used to a temperature at which an isotropic phase is obtained and then slowly cooling the liquid crystal composition to room temperature.
When the coating film is subjected to the rubbing treatment, the two substrates are arranged so as to face each other so that the rubbing directions of the coating films are opposite to each other at a predetermined angle, for example, orthogonal or antiparallel.
As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include a nematic liquid crystal and a smectic liquid crystal, and among them, the nematic liquid crystal is preferable.

Then, if necessary, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. As the polarizing plate attached to the outer surface of the liquid crystal cell, a polarizing plate called an "H film" in which polyvinyl alcohol is stretched and oriented to absorb iodine is sandwiched between a cellulose acetate protective film or the H film itself. A polarizing plate made of the above can be mentioned.

The liquid crystal display element of the present invention can be effectively applied to various devices, for example, a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, a smartphone, and the like. It can be used for various display devices such as various monitors, liquid crystal televisions, and information displays. The polymer composition contained in the liquid crystal alignment agent is a liquid crystal alignment film for a retardation film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmission scattering type liquid crystal photochromic element. Alternatively, it can also be used for applications other than these, such as a protective film for a color filter, a gate insulating film for a flexible display, and a substrate material.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited thereto. The abbreviations for the compounds used and the methods for measuring each physical property are as follows.

(Specific diamine)
WA-1: A compound represented by the following formula (WA-1)

(Other diamines)
A1 to A2: Compounds represented by the following formulas (A1) to (A2), respectively.

(Tetracarboxylic dianhydride)
B1: Compound represented by the following formula (B1)

(solvent)
NMP: N-Methyl-2-pyrrolidone BCS: Ethylene glycol monobutyl ether

(Measurement of viscosity)
The viscosity of the solution was measured at a temperature of 25 ° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a cone rotor TE-1 (1 ° 34', R24). did.

<Synthesis of polymer>
(Synthesis Example 1)
WA-1 (1.26 g, 5.20 mmol), A2 (4.14 g, 20.8 mmol), and B1 (7.34 g, 25.0 mmol) were mixed in NMP (93.5 g) and at 70 ° C. The reaction was carried out for 15 hours to obtain a polyamic acid solution (PAA-1) (viscosity: 483 mPa · s) having a resin solid content concentration of 12% by mass. The ratio of WA-1 in the diamine component was 20 mol% with respect to 1 mol of the diamine component.

(Comparative synthesis example 1)
A1 (1.55 g, 5.20 mmol), A2 (4.14 g, 20.8 mmol) and B1 (7.34 g, 25.0 mmol) were mixed in NMP (95.6 g) and reacted at 70 ° C. for 15 hours. A polyamic acid solution (PAA-R1) (viscosity: 461 mPa · s) having a resin solid content concentration of 12% by mass was obtained.

<Preparation of liquid crystal alignment agent>
(Example 1)
NMP (4.25 g) and BCS (2.00 g) were added to the polyamic acid solution (PAA-1) (3.75 g) obtained in Synthesis Example 1, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (liquid crystal alignment agent). V-1) was obtained. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.

(Comparative Example 1)
NMP (4.25 g) and BCS (2.00 g) were added to the polyamic acid solution (PAA-R1) (3.75 g) obtained in Comparative Synthesis Example 1, and the mixture was stirred at room temperature for 2 hours to prepare a liquid crystal alignment agent. (VR1) was obtained. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
Using the liquid crystal alignment agent obtained above, an FFS-driven liquid crystal cell was produced by the procedure shown below, and afterimage evaluation was performed.

<Manufacturing of FFS type liquid crystal display element>
A liquid crystal cell having a configuration of a Fringe Field Switching (FFS) mode liquid crystal display element is manufactured.
First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. An ITO electrode having a solid pattern, which constitutes a counter electrode as a first layer, is formed on the substrate. A SiN (silicon nitride) film formed by a CVD (chemical vapor deposition) method is formed as a second layer on the counter electrode of the first layer. The film thickness of the SiN film of the second layer is 500 nm, and it functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an ITO film as a third layer is arranged to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-teeth shape in which a plurality of electrode elements having a width of 3 μm in which the central portion is bent at an internal angle of 160 ° are arranged in parallel with an interval of 6 μm. The pixel has a first region and a second region with a line connecting the bent portions of the plurality of electrode elements as a boundary.

Comparing the first region and the second region of each pixel, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrodes are formed so as to form an angle (clockwise) of + 10 ° in the first region of the pixel, and the pixel is formed in the second region of the pixel. The electrode elements of the electrodes are formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (inplane switching) of the liquid crystal in the substrate surface induced by the voltage application between the pixel electrode and the counter electrode are mutual. It is configured to be in the opposite direction.

Next, after filtering the liquid crystal alignment agents obtained in Examples and Comparative Examples with a filter having a pore size of 1.0 μm, a columnar column having a height of 4 μm in which an ITO film is formed on the prepared substrate with electrodes and the back surface. Each was applied to a glass substrate having a spacer by spin coating. After drying on a hot plate at 80 ° C. for 5 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 20 minutes to obtain a polyimide film having a film thickness of 100 nm. This polyimide film is rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 500 rpm, moving speed: 30 mm / sec, pushing length: 0.3 mm, rubbing direction: tilted 10 ° with respect to the third layer IZO comb tooth electrode. After that, it was washed by irradiating it with ultrasonic waves for 1 minute in pure water, and water droplets were removed by air blowing. Then, it was dried at 80 degreeC for 15 minutes to obtain a substrate with a liquid crystal alignment film. A set of these two substrates with a liquid crystal alignment film is printed with a sealant with the liquid crystal injection port left on the substrate, and the liquid crystal alignment film surface faces the other substrate and the rubbing direction is antiparallel. I stuck them together so that they would be. Then, the sealant was cured to prepare an empty cell having a cell gap of 4 μm. A negative liquid crystal display MLC-7026-100 (manufactured by Merck Group) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain an FFS type liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour, left at 23 ° C. overnight, and then used for evaluation of liquid crystal orientation.

<Measurement of relaxation rate of accumulated charge>
The liquid crystal cell produced above is placed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the pixel electrode and the counter electrode are short-circuited to have the same potential. The LED backlight was irradiated from below, and the angle of the liquid crystal cell was adjusted so that the brightness of the transmitted light of the LED backlight measured on the two polarizing plates was minimized. Next, the VT curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 60 Hz to the liquid crystal cell, and the AC voltage having a relative transmittance of 23% was calculated as the drive voltage.
In the afterimage evaluation, an AC voltage having a frequency of 60 Hz having a relative transmittance of 23% was applied to drive the liquid crystal cell, and at the same time, a DC voltage of 1 V was applied to drive the liquid crystal cell for 120 minutes. After that, only the application of the DC voltage was stopped, and the engine was driven only with the AC voltage for another 15 minutes.
If the relative transmittance is relaxed to 25% or less by the time 10 minutes have passed since the application of the DC voltage was stopped, it is regarded as "good", and it takes 10 minutes or more until the relative transmittance decreases to 25% or less. Was required, it was defined as "defective" and evaluated. The results are shown in Table 1.
The afterimage evaluation according to the above-mentioned method was performed under the temperature condition that the temperature of the liquid crystal cell was 40 ° C.

As can be seen from the above results, the liquid crystal alignment film obtained from the liquid crystal alignment agent using diamine WA-1 exhibits a relaxation rate of accumulated charge higher than that of the liquid crystal alignment film obtained from the liquid crystal alignment agent using diamine A1. I understood. Specifically, it is shown in the comparison between Example 1 and Comparative Example 1 shown in Table 1.

The liquid crystal display element using the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be suitably used for the liquid crystal display element. These elements are also useful in liquid crystal displays for display purposes, as well as in dimming windows and optical shutters that control the transmission and blocking of light.

The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2020-12304 filed on July 17, 2020 are cited here as the disclosure of the specification of the present invention. It is something to incorporate.

Claims (11)

1. Obtained using a diamine represented by the following formula (1a), a diamine component containing a diamine represented by the following formula (1b), and a tetracarboxylic acid derivative component containing an aromatic tetracarboxylic acid dianhydride or a derivative thereof. A liquid crystal aligning agent containing at least one polymer (A) selected from the group consisting of a polyimide precursor to be obtained and a polyimide which is an imidized product of the polyimide precursor, wherein the diamine component is the formula (1a). ) Is contained in an amount of 5 to 95 mol% with respect to 1 mol of the diamine component used.
   

   

   (Any hydrogen atom on the benzene ring may be substituted with a monovalent substituent.)
   

   

   (Y represents a divalent organic group having at least one structure selected from the group consisting of a nitrogen atom-containing heterocycle which may be substituted and an amine structure represented by the following formula (b) in the molecule. )
   

   

   (R represents a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or a group having —O— between carbon-carbon bonds of the chain hydrocarbon group having 1 to 10 carbon atoms. Any hydrogen atom can be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, and fluorine. It may be substituted with at least one selected from the group consisting of atoms.)
2. The liquid crystal alignment agent according to claim 1, wherein the diamine represented by the formula (1a) is a diamine represented by the following formulas (1a-1) to (1a-3).
   

   
3. The liquid crystal alignment agent according to any one of claims 1 to 2, wherein 5 to 95 mol% of the diamine component is a diamine represented by the formula (1b).
4. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein the aromatic tetracarboxylic dianhydride is represented by the following formula (Ta).
   

   

   (Xa represents a structure selected from the group consisting of the following formulas (a-1) to (a-9).)
   

   

   (J and k are integers of 0 or 1, and A ₁ and A ₂ are independent, single bond, -O-, -CO-, -COO-, phenylene, -SO _{2-, or-, respectively.} NRCO- (R represents. a hydrogen atom or a methyl group) in representing the. * represents a bond that binds to the acid anhydride group. formula (a-2), 2 two a ₂ is be the same or different good.)
5. The liquid crystal alignment agent according to claim 4, wherein the formula (a-1) or (a-2) represents a structure selected from the group consisting of the following formulas (a-10) to (a-25).
   

   

   

   ("*" In the formula represents a bond that binds to an acid anhydride group.)
6. The tetracarboxylic acid derivative component contains 10 to 100 mol% of the aromatic tetracarboxylic dianhydride represented by the formula (Ta) or a derivative thereof with respect to 1 mol of the tetracarboxylic acid derivative component used. , The liquid crystal alignment agent according to claim 4 or 5.
7. The liquid crystal alignment agent according to any one of claims 1 to 6, wherein Y is a divalent organic group represented by the following formulas (y1) to (y8).
   

   

   (R is synonymous with the above formula (b). Q represents a nitrogen atom-containing heterocycle which may be substituted. L is a single bond, —O—, —C (= O, respectively) independently of each other. )-, -NR- (R is synonymous with the above formula (b)), -NRCO- (R is synonymous with the above formula (b)), -CH ₂ -,-(CH ₂ ) _n -(N represents an integer of 2 to 12), or at least a part of -CH _{2- of the- (CH 2} ) _n- is -O-, -C (= O)-, -NR- (R). Represents a group replaced with the above formula (b)) or -NRCO- (R is synonymous with the above formula (b)). L'is an independent single bond, respectively. _{-C (= O) -, -} CH 2 -, - (CH 2) n - (. n represents an integer of 2 to 12), or the - _{(CH 2) n} - -CH ₂ - of at least one Represents a group in which the part is replaced with -O- or -C (= O)-. Any hydrogen atom on the benzene ring has an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a carbon number of carbon atoms. It may be substituted with at least one selected from the group consisting of 1 to 3 fluorine atom-containing alkyl groups, 1 to 3 carbon atoms-containing alkoxy groups and fluorine atoms. L, Q, R and L'are substituted. When there are a plurality of them in one formula, they may be the same or different independently.)
8. The diamine represented by the above formula (1b) is represented by the diamines represented by the following formulas (1b-1) to (1b-20) and the following formulas (1b'-1) to (1b'-11). Claims 1-7, selected from diamine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole and N-methyl-3,6-diaminocarbazole. The liquid crystal aligning agent according to any one item.
   

   

   

   
9. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 8.
10. A liquid crystal display element provided with the liquid crystal alignment film according to claim 9.
11. A method for producing a liquid crystal alignment film, which comprises the following steps (1) to (3).
    Step (1): Step of applying the liquid crystal alignment agent according to any one of claims 1 to 8 onto a substrate Step (2): Step of firing the applied liquid crystal alignment agent Step (3): Step (2) ), The process of orienting the film obtained in