WO2022014345A1

WO2022014345A1 - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2022014345A1
Application number: PCT/JP2021/024966
Authority: WO
Inventors: 美希豊田; 佳和原田
Original assignee: 日産化学株式会社
Priority date: 2020-07-14
Filing date: 2021-07-01
Publication date: 2022-01-20
Also published as: JPWO2022014345A1; CN116615689A; JP7315106B2; TW202214828A; CN116615689B; KR20230038504A

Abstract

Provided are: a liquid crystal aligning agent whereby a liquid crystal alignment film can be obtained that has a high voltage retention rate, has a high optical transmittance, can relax accumulated charge quickly, and has excellent afterimage characteristics; said liquid crystal alignment film; and a liquid crystal display element.　This liquid crystal aligning agent is characterized by containing at least one type of polymer (P) selected from the group consisting of: a polyimide precursor obtained by using a diamine component including a diamine (1) indicated by formula (1); and a polyimide, which is the polyimide precursor that has been imidized. (R indicates a monovalent organic group and R₁ and R₂ indicate a saturated or unsaturated C1–6 monovalent hydrocarbon group or a C3–6 alicyclic hydrocarbon group. Some of the hydrogen atoms in the hydrocarbon groups in R₁ and R₂ may be substituted.

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 obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

Conventionally, as a liquid crystal display element, various drive methods having different electrode structures and physical properties of liquid crystal molecules used have been developed. For example, TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical). Various display elements such as an Element) type, an IPS (In-Plane Switching) type, and an FFS (Fringe Field Switching) type are known.

Among them, the VA type liquid crystal display element has a wide viewing angle, a fast response speed, a large contrast, and can eliminate the need for rubbing processing in the production process. Widely used mainly for monitors. In the VA type liquid crystal display element, a photopolymerizable compound is added to the liquid crystal composition in advance, and the liquid crystal cell is irradiated with ultraviolet rays while applying a voltage to increase the response speed of the liquid crystal. ) Method (see, for example, Patent Document 1 and Non-Patent Document 1) is the mainstream.

On the other hand, the liquid crystal display element generally has a liquid crystal alignment film for orienting liquid crystal molecules. As a material for the liquid crystal alignment film, for example, polyamic acid, polyamic acid ester, polyimide, polyamide and the like are known.
The liquid crystal alignment film is required to have various properties in addition to the liquid crystal alignment. For example, in the PSA type liquid crystal display element, when static electricity is accumulated in the liquid crystal cell, or when electric charge is accumulated in the liquid crystal cell by applying a positive / negative asymmetric voltage generated by driving, these accumulated charges are accumulated. A liquid crystal alignment film that suppresses the accumulation of static electricity and has little afterimage is required because it affects the display as a disorder of the liquid crystal alignment or an afterimage and significantly deteriorates the display quality of the liquid crystal element. As a liquid crystal alignment film that solves such a problem, Patent Document 2 proposes a polyimide-based liquid crystal alignment film having a pyrrole structure.

In recent years, large-screen, high-definition LCD televisions have been widely put into practical use, and liquid crystal alignment films used for such applications are required to be more reliable than before. In particular, it is required to exhibit higher initial characteristics with respect to the electrical characteristics which are the basic characteristics of the liquid crystal alignment film. As a liquid crystal alignment film that solves this problem, Patent Document 3 proposes a polyimide-based liquid crystal alignment film having a diphenylamine structure.

Japanese Patent Application Laid-Open No. 2003-307720 International Publication No. 2019/0133339 International Publication No. 2009/093709

In addition to the above, in recent years, in ultra-high-definition liquid crystal display elements such as 4K and 8K, the occupancy ratio of black matrix (BM) and TFT becomes large, and the aperture ratio of the panel decreases, so the light of the display unit The improvement of transmittance is emphasized.

In view of the above circumstances, an object of the present invention is a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film having a high voltage retention rate and a high light transmittance, quick relaxation of accumulated charges, and excellent afterimage characteristics. The present invention is to provide the liquid crystal alignment film and a liquid crystal display element using the same.

As a result of diligent research to achieve the above-mentioned problems, the present inventor has found that a liquid crystal aligning agent containing a specific component is effective for achieving the above-mentioned object, and completes the present invention. It came to.
The present invention is at least one selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (1) represented by the following formula (1) and a polyimide which is an imidized product of the polyimide precursor. It is in a liquid crystal alignment agent characterized by containing a polymer (P), a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

(R represents a monovalent organic group, and R ₁ and R ₂ represent a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 3 to 6 carbon atoms. A part of the hydrogen atom of the hydrocarbon group in R ₁ and R _{2 may be substituted.)}

According to the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment film having a high voltage retention and a high light transmittance, quick relaxation of accumulated charges, and excellent afterimage characteristics.
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, the diamine, which is the raw material of the polymer component used in the liquid crystal alignment agent of the present invention, is high because the presence of a substituent at the ortho position of the amino group causes steric hindrance and suppresses the formation of charge transfer. A liquid crystal alignment film having a light transmittance can be obtained, and since the polymer obtained from the above diamine has a conjugated structure, the accumulated charge can be quickly relaxed and a liquid crystal alignment film having excellent afterimage characteristics can be obtained. it is conceivable that.

(Polymer (P))
The liquid crystal alignment agent of the present invention is selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (1) represented by the following formula (1) and a polyimide which is an imidized product of the polyimide precursor. It contains at least one polymer (P).

In the above formula (1), R, R ₁ and R ₂ are as defined above, respectively.
The monovalent organic group in R includes a monovalent organic group having an aromatic ring structure, a monovalent chain hydrocarbon group having 1 to 30 carbon atoms, or a monovalent alicyclic hydrocarbon having 3 to 30 carbon atoms. Hydrocarbon groups are preferred. A part of the hydrogen atom of the chain hydrocarbon group or the alicyclic hydrocarbon group may be substituted, and a part of the methylene group thereof is substituted with an oxygen atom, a carbonyl group or -COO-. May be.
Examples of the monovalent chain hydrocarbon group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms. When R is a chain hydrocarbon group or an alicyclic hydrocarbon group, a part of the hydrogen atom contained in these hydrocarbon groups may be substituted, and the substituent may be a halogen atom (fluorine atom, Chlorine atom, bromine atom, iodine atom), hydroxyl group, cyano group, alkyl group having 1 to 9 carbon atoms, alkoxy group having 1 to 9 carbon atoms, fluoroalkyl group having 1 to 9 carbon atoms and the like can be mentioned. Of these, an alkyl group having 1 to 6 carbon atoms or a fluoroalkyl group having 1 to 6 carbon atoms is more preferable, and an alkyl group having 1 to 6 carbon atoms is particularly preferable.

The monovalent alicyclic hydrocarbon group having 3 to 30 carbon atoms may be composed of only an alicyclic structure, or may contain a chain structure as a part thereof. Examples of the alicyclic structure include cyclopentane, cyclohexane, cycloheptane, cyclooctane, norbornane, and adamantane.
The monovalent organic group having the aromatic ring structure may be composed of only the aromatic ring structure, or may contain at least one of the chain structure and the alicyclic structure as a part thereof. The aromatic ring structure may be a benzene ring, a condensed benzene ring such as a naphthalene ring or an anthracene ring, and a complex such as a thiophene ring, a pyrrole ring, a furan ring, a pyridine ring, a pyrimidine ring, and a triazine ring. It may be an aromatic ring. The monovalent group having the aromatic ring structure may have only one aromatic ring structure or may have a plurality of aromatic ring structures. When a plurality of aromatic ring structures are present, the plurality of aromatic ring structures may be bonded by a single bond, and in this case, specific examples thereof include biphenyl and terphenyl. Further, a chain structure or an alicyclic structure may exist so as to connect a plurality of aromatic ring structures. At least one of these aromatic ring structures, chain structures and alicyclic structures may have a substituent. The substituents include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), a hydroxyl group, a cyano group, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, and 1 to 9 carbon atoms. Fluoroalkyl groups and the like can be mentioned.

A preferred example of the monovalent organic group having the aromatic ring structure in R is a structure represented by the following formula (Ar).

( ^Ra is a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), hydroxyl group, cyano group, alkyl group having 1 to 9 carbon atoms, alkoxy group having 1 to 9 carbon atoms, or 1 to 9 carbon atoms. the .m representing the fluoroalkyl group is an integer from 0 to 5, when m is 2 to 5, with. * is the definition plurality of R ^a independently represents a bond.)

Saturated or unsaturated monovalent hydrocarbon groups having 1 to 6 carbon atoms in R ₁ and R ₂ include alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, and 2 to 6 carbon atoms. Examples include an alkynyl group. Examples of the alicyclic hydrocarbon group having 3 to 6 carbon atoms in R ₁ and R _{2 include a cyclopentyl group and a cyclohexyl group.} A part of the hydrogen atom of the hydrocarbon group in R ₁ and R ₂ may be substituted, and examples of the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and a hydroxyl group.
From the viewpoint of efficiently obtaining the effects of the present invention, R, R ₁ and R ₂ are preferably alkyl groups having 1 to 5 carbon atoms independently of each other.
Specific examples of the alkyl groups having 1 to 5 carbon atoms in R, R ₁ and R ₂ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group and tert. -Butyl group, n-pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group can be mentioned. Of these, an alkyl group having 1 to 3 carbon atoms is preferable.

Preferred specific examples of the diamine (1) represented by the above formula (1) include the following formulas (d-1) to (d-4).

The polymer (P) contained in the liquid crystal aligning agent of the present invention is particularly applicable to the liquid crystal aligning agent for the liquid crystal display element of the TN method, STN method, VA method, PSA method, and SC-PVA mode. In addition to the diamine represented by the formula (1), a diamine component containing a diamine (s) having at least one structure selected from the group consisting of the following formulas (S1), (S2) and (S3) is used. It is preferable that the polymer is at least one selected from the group consisting of the polyimide precursor thus obtained and the polyimide which is an imidized product of the polyimide precursor.

In formula (S1), X ¹ and X ² are independently single-bonded,-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON. (CH ₃ )-, -N (CH ₃ ) CO-, -NH-, -O-, -COO-, -OCO-, or-((CH ₂ ) _a1- A ₁ ) _m1- (a1 is 1-) It is an integer of 15, A ₁ represents an oxygen atom or -COO-, m ₁ is 1 to 2, and a plurality of a 1 and A ₁ _{when m 1} is 2 may be the same or different. It may be.). G ¹ and G ² each independently represent a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. The arbitrary hydrogen atom on the cyclic group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, and a fluorine-containing alkoxy group having 1 to 3 carbon atoms. And may be substituted with at least one selected from the group consisting of fluorine atoms. m and n are independently integers of 0 to 3, and the sum of m and n is 1 to 4. When there are a plurality of m and n, the plurality of X ¹ , X ² , G ¹ and G ² may be the same or different. R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxy alkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming ^{R 1 is substituted with a fluorine atom.} May be.

Examples of the divalent cyclic group in G ¹ and G ² include a cyclohexylene group and a phenylene group. Any hydrogen atom on these cyclic groups may be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. It may be substituted with a group or a fluorine atom. m and n are independently integers of 0 to 3, and the total of m and n is 1 to 4. From the viewpoint of enhancing the liquid crystal orientation, the total of m and n is more preferably 2 to 4.

In formula (S2), X ³ is a single bond, -CONH-, -NHCO-, -CON (CH ₃ )-, -N (CH ₃ ) CO-, -NH-, -O-, -CH ₂ O. -, -COO- or -OCO-. R ² represents an alkyl group having 1 to 20 carbon atoms or an alkoxy alkyl group having 2 to 20 carbon ^{atoms, and any hydrogen atom forming R 2} may be substituted with a fluorine atom.
Further, R ² is preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms from the viewpoint of enhancing the liquid crystal orientation.

In formula (S3), X ⁴ represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -OCH _{2-, -COO- or -OCO-.} R ³ represents a structure having a steroid skeleton. Further, R ³ preferably has a structure containing a cholestanyl group, a cholesteryl group or a lanostannyl group.

Preferred specific examples of the formula (S1) include the following formulas (S1-x1) to (S1-x7).

In the formula (S1-x1) ~ (S1 -x7), R 1 is as defined above. X ^p is-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-, -N (CH ₃ ) CO-, -NH. -, _{-O-, -CH 2} O-, -CH ₂ OCO-, -COO-, or -OCO-. A ₁ represents an oxygen atom or -COO- * (where a bond with an "*" binds to (CH ₂ ) _a2 ), and A ₂ is an oxygen atom or * -COO- (where *). The bond with (CH ₂ ) _{represents (CH 2) a2} ). a ₁ and a ₃ are independently integers of 0 or 1, a ₂ is an integer of 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group. ..

As a preferred embodiment of the formula [S2], X ³ is any of -O-, -CH ₂ O-, -COO- or -OCO-, and R ² is an alkyl group having 3 to 20 carbon atoms or an alkyl number of carbon atoms. preferably represents an alkoxyalkyl group of 2 to 20, more preferably when R ² is an alkyl group having 3 to 20 carbon atoms, any hydrogen atoms that form the R ² may be substituted by fluorine atoms ..

The following formula (S3-x) is given as a preferable specific example of the above formula (S3). In the formula (S3-x), X represents the formula (X1), the formula (X2), or −CH ₂ O—, and Col represents the formula (Col1), the formula (Col2), or the formula (Col3). Representing, G represents the formula (G1), the formula (G2), the formula (G3) or the formula (G4). In the formula, Me represents a methyl group and * represents a bond.

As a preferable diamine (s) having a structure represented by any of the above formulas (S1) to (S3), a preferable diamine (s) having a structure represented by the above formulas (S1) to (S3) and at least one benzene. A diamine having a ring is preferable. Preferred examples of the diamine (s) include diamines represented by the following formula (d1) or formula (d2).

In the formulas (d1) and (d2), Y represents the side chain structure represented by the above formulas (S1) to (S3). In addition, X is a single bond, -O-, -C (CH ₃ ) _2- , -NH-, -CO-, -COO-, -CONH-,-(CH ₂ ) _m- , -SO _2- , _{-O- (CH 2} ) _m- O-, -OC (CH ₃ ) _2- , -CO- (CH ₂ ) _m- , -CO- (CH ₂ ) _m -CO-, -NH- (CH) _{_{_{_{2) m -, - NH- (}}}} CH 2) m -NH -, - SO 2 - (CH 2) m -, - SO 2 - (CH 2) m -SO 2 -, - CONH- (CH 2) m -, -CONH- (CH ₂ ) _m -NHCO-, or -COO- (CH ₂ ) _m- OCO-. m is an integer from 1 to 8. In the above formula (d2), the two Ys may be the same as or different from each other.

Preferred specific examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-18).

(N is an integer from 1 to 20.)

Preferred specific examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6).

In the above formulas (d2-1) to (d2-6), X ^p1 to X ^p8 ^{are independently synonymous with X p} in the above formulas (S1-x1) to (S1-x6), and are X ^s1. ~ X ^s4 independently represent -O-, -CH ₂ O-, -COO- or -OCO-. X _a to X _f represent a single bond, -O-, -NH-, or -O- (CH ₂ ) _m- O- (m is an integer of 1 to 8), and R ^1a to R ^1h. Independently represent an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms.

(Manufacturing of polymer (P))
The polymer (P) contained in the liquid crystal alignment agent of the present invention may be composed of one component or two or more components of a polyimide precursor and / or a polyimide which is an imidized product of the polyimide precursor. Here, the polyimide precursor is a polymer from which polyimide can be obtained by imidization of a polyamic acid, a polyamic acid ester, or the like. Preferred specific embodiments of the polymer (P) include, but are not limited to, the following two types.

At least one polymer selected from the group consisting of a polyimide precursor obtained by using a diamine component containing the diamine (1) and the diamine (s), and a polyimide which is an imidized product of the polyimide precursor (hereinafter,). , Also called a copolymer).
At least one polymer (p-1) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing the diamine (1) and a polyimide which is an imidized product of the polyimide precursor, and the diamine (p-1). A mixture with at least one polymer (p-2) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing s) and polyimide which is an imidized product of the polyimide precursor (hereinafter, polymer). Also called a blend.).
The above-mentioned copolymer or polymer blend may be used alone or in combination of both.

<Diamine component>
The polyamic acid (P), which is a polyimide precursor of the polymer (P), is a diamine component containing the diamine (1), preferably a diamine component containing a diamine (s) in addition to the diamine (1). It can be obtained by a polymerization reaction with a tetracarboxylic acid component.
In this case, the amount of the diamine (1) used is preferably 1 to 100 mol%, more preferably 1 to 99 mol%, still more preferably 5 to 95 mol% with respect to the diamine component to be reacted with the tetracarboxylic acid component. ..

When diamine (s) is used in addition to the above diamine (1), the amount of diamine (s) used is preferably 1 to 99 mol% with respect to the diamine component to be reacted with the tetracarboxylic acid component, and 1 to 95. More preferably mol%.

The diamine component used in the production of the polyamic acid (P) may contain a diamine other than the diamine (1) and the diamine (s) (hereinafter, also referred to as other diamines). Examples of other diamines are given below, but the present invention is not limited thereto.

p-phenylenediamine, m-phenylenediamine, 4- (2- (methylamino) ethyl) aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, the following formula ( 3b-1) to diamines having a carboxy group of the formula (3b-4), 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether 1,2-bis (4-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (4-aminophenoxy) ) Diamine, 1,3-bis (4-aminophenoxy) benzene, 1,2-bis (4-aminophenoxy) ethane, 1,2-bis (4-amino-2-methylphenoxy) ethane, 1,3- Bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 4 -(2- (4-Aminophenoxy) ethoxy) -3-fluoroaniline, di (2- (4-aminophenoxy) ethyl) ether, 4-amino-4'-(2- (4-aminophenoxy) ethoxy) Biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) Biphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, diamines represented by the following formulas (nh-1) to (nh-6), 2 , 2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2'-bis (4-aminophenyl) ) Propane, diamine having a urea bond such as 1,3-bis (4-aminophenethyl) urea, 2- (2,4-diaminophenoxy) ethyl methacrylate, 2,4-diamino-N, N-diallyl aniline, etc. Diamine having a photopolymerizable group at the end, diamine having a radical initiation function such as the following formulas (R1) to (R5), 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 9,9-bis Light irradiation such as (4-aminophenyl) fluorene Diamine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6- Diaminocarbazole, diamine having a heterocycle such as the following formulas (z-1) to (z-18), diamine having a diphenylamine skeleton such as the following formulas (Dp-1) to (Dp-9), the following formula (5-) Groups such as 1) to (5-10) "-N (D)-" (D represents a protective group that is desorbed by heating and replaced with a hydrogen atom, and is preferably a t-butoxycarbonyl group. ), Diamines having an oxazoline structure such as the following formulas (Ox-1) to (Ox-2), diamines according to International Publication No. 2016/125870, and 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- is indicated, m1 and m2 independently indicate an integer of 0 to 4, and m1 + m2 indicates an integer of 1 to 4. Equation (3b-2). 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 in the formula (3b-3). . 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- indicates, m6 is an integer of 1 to 4).

(In equations (R3) to (R5), n is an integer of 1 to 6.)

(Boc is a tert-butoxycarbonyl group. In the present invention, the same applies to the following.)

Among the above other diamines, p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, among others, from the viewpoint of preferably obtaining the effects of the present invention. 2,2'-dimethyl-4,4'-diaminobiphenyl, 2- (2,4-diaminophenoxy) ethyl methacrylate, 2,4-diamino-N, N-diallylaniline, the above formulas (R1) to (R5). ), Diamines represented by the above formulas (z-1) to (z-18), diamines represented by the above formulas (5-1) to (5-10), and the above formula (Ox-). Diamines represented by 1) to (Ox-2) are preferable.

When other diamines are used in addition to the above diamine (1), the amount of the other diamines used is preferably 1 to 99 mol%, more preferably 5 to 95, based on the total diamine components used. It is mol%.
When other diamines are used in addition to the above diamines (1) and diamines (s), the amount of the diamines (s) used is preferably 98 mol% or less with respect to the diamine component to be reacted with the tetracarboxylic acid component. More preferably, it is 94 mol% or less.

The amount of the diamine represented by the above formulas (5-1) to (5-10) is preferably 5 to 40 mol% with respect to the total diamine component used in the production of the polyamic acid (P). , More preferably 10-40 mol%.

In a liquid crystal display element using the PSA method or SC-PVA mode, from the viewpoint of increasing the response speed, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, a diamine having a photopolymerizable group at the end, and the above formula ( The diamine represented by any of R1) to (R5) and the diamine represented by the above formulas (z-1) to (z-18) are used at least one in the case of producing the polyamic acid (P). The amount used can be preferably 1 to 40 mol%, more preferably 5 to 40 mol%, based on the total diamine component used in the production of the polyamic acid (P).

<Tetracarboxylic acid component>
When the polyamic acid (P) is produced, the tetracarboxylic acid component to be reacted with the diamine component is not only tetracarboxylic acid dianhydride, but also tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid. Derivatives of tetracarboxylic acid dianhydride such as acid dialkyl ester dihalide can also be used.

Examples of the tetracarboxylic dianhydride or a derivative thereof include aromatic, aliphatic or alicyclic tetracarboxylic dianhydride, or derivatives thereof. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to the aromatic ring. Aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it does not have to be composed only of a chain hydrocarbon structure, and may have an alicyclic structure or an aromatic ring structure as a part thereof.

The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to the alicyclic structure. However, none of these four carboxy 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.

Among them, the tetracarboxylic dianhydride or a derivative thereof is preferably represented by the following formula (T) or a derivative thereof.

However, in the formula (T), X represents a structure selected from the group consisting of the following formulas (x-1) to (x-13).

In the above formulas (x-1) to (x-13), R ¹ to R ⁴ are independent hydrogen atoms, halogen atoms, alkyl groups having 1 to 6 carbon atoms, and alkenyl groups having 2 to 6 carbon atoms, respectively. , 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. R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. j and k are integers of 0 or 1, and A ₁ and A ₂ are independent, single bond, ether (-O-), carbonyl (-CO-), ester (-COO-), and phenylene, respectively. Represents a group, a sulfonyl group (-SO _2- ) or an amide group (-CONH-). * 1 is a bond that binds to one acid anhydride group, and * 2 is a bond that binds to the other acid anhydride group. In the formula (x-13), 2 pieces of A ₂ may being the same or different.

More preferable specific examples of the above formula (x-1) include the following formulas (X1-1) to (X1-6). In the formula, * represents a bond.

Preferred specific examples of the above formulas (x-12) and (x-13) include the following formulas (x-14) to (x-29). * Represents a bond.

As a preferable specific example of the tetracarboxylic dianhydride represented by the above formula (T) or a derivative thereof, X is the above formulas (x-1) to (x-7) and (x-11) to (x). The one selected from -13) can be mentioned.

The ratio of the tetracarboxylic dianhydride or its derivative represented by the above formula (T) is preferably 1 mol% or more, more preferably 5 mol% or more, based on 1 mol of the total tetracarboxylic acid component used. It is preferable, 10 mol% or more is more preferable.
The tetracarboxylic dianhydride and its derivative used for producing the polyamic acid (P) may contain a tetracarboxylic dianhydride other than the above formula (T) or a derivative thereof.

The polyamic acid (P) is produced by reacting the diamine component and the tetracarboxylic acid component in a solvent (condensation polypolymerization). 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 above 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 component are reacted in a solvent, the reaction can be carried out at any concentration, but the concentration of the diamine component and the tetracarboxylic acid component with respect to the above solvent is preferably 1 to 50 mass 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 component (total number of moles of the diamine component / total number of moles of the tetracarboxylic acid component) shall be 0.8 to 1.2. Is preferable. Similar to a normal polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the produced polymer.

The polyamic acid ester which is a polyimide precursor is, for example, [I] a method of reacting a polyamic acid obtained by the above synthetic reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, [II]. III] It can be obtained by a known method such as a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

[Polyimide]
The polyimide contained in the liquid crystal alignment agent of the present invention is a polyimide obtained by ring-closing the above-mentioned polyimide precursor. In polyimide, the ring closure rate (also referred to as imidization rate) of the amic acid group does not necessarily have to be 100%, and can be arbitrarily adjusted according to the application and purpose.

Examples of the method for imidizing the polyimide precursor to obtain polyimide include thermal imidization in which the solution of the polyimide precursor is heated as it is, or catalytic imidization in which a catalyst is added to the solution of the polyimide precursor. The temperature at which the polyimide precursor is thermally imidized in the solution is 100 to 400 ° C., preferably 120 to 250 ° C., and it is preferable to remove the water generated by the imidization reaction from the system.

The catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to the solution of the polyimide precursor and stirring at −20 to 250 ° C., preferably 0 to 180 ° C. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times the amount of the amic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times the amic acid group. It is double. 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 and pyromellitic anhydride, 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 polyimide from the reaction solution for imidization of the polyimide precursor, 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 and hydrocarbons. It is preferable to use three or more kinds of solvents selected from these because the efficiency of purification is further improved.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polyimide precursor and the polyimide is preferably 5,000 to 1,000,000, more preferably 10,000 to 150. It is 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 of the liquid crystal display element can be ensured.

<Terminal sealant>
The polymer (P) in the present invention may be a terminal-sealed polymer by using an appropriate terminal-sealing agent together with the above-mentioned tetracarboxylic acid component and diamine component in the production thereof. 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 (P) in the present invention include an amino group, a carboxy group, an acid anhydride group or a derivative thereof. An amino group, a carboxy group, an acid anhydride group, or a derivative thereof can be obtained by a usual condensation reaction or the following terminal encapsulant, and the derivative can be obtained, for example, by using the following terminal encapsulant. Obtainable.

Examples of the terminal encapsulant include acetic anhydride, maleic anhydride, nagic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, and the following formulas. Compound represented by any of (m-1) to (m-6), 3- [3- (trimethoxysilyl) propyl] -3,4-dihydrofuran-2,5-dione, 4,5, Acid anhydrides such as 6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynylphthalic anhydride;

Dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride and 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, n-heptylamine, Monoamine compounds such as 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.

(Liquid crystal alignment agent)
The liquid crystal alignment agent of the present invention is a liquid composition in which the polymer (P) and other components used as needed are preferably dispersed or dissolved in a suitable solvent.
In the liquid crystal alignment agent of the present invention, in addition to the polymer (P), other weights are used for the purpose of improving, for example, electrical characteristics (eg, high voltage retention characteristics), vertical orientation, and solution characteristics. A coalescence (hereinafter, also referred to as another polymer) may be contained.
The content ratio of the other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and further 20 to 80 parts by mass with respect to 100 parts by mass of the total amount of the polymers contained in the liquid crystal alignment agent. preferable.

The other polymer is not particularly limited, and is, for example, a group consisting of a polyimide precursor obtained by using the diamine component not containing the diamine (1) and the tetracarboxylic acid component, and a polyimide which is an imidized product of the polyimide precursor. At least one polymer (B) selected from, polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate and the like. The main skeleton is mentioned. Among them, at least one selected from the group consisting of the polymer (B), polyamide, polyurea, polyorganosiloxane, poly (meth) acrylate and polyester is preferable. In addition, other polymers may be used in combination of 2 or more types.

(Polymer (B))
As the polymer (B), at least one selected from the group consisting of a polyimide precursor obtained by using the diamine component containing the diamine (s) and an imidized product of the polyimide precursor from the viewpoint of enhancing electrical characteristics. The polymer of is more preferable. The preferred embodiment of the diamine (s) used to obtain the polymer (B) is the same as the diamine (s) exemplified in the polymer (P). Further, as the diamine component used to obtain the polymer (B), in addition to the above diamine (s), other diamines exemplified by the above polymer (P) can also be used. As the other diamines, among them, a diamine having the radical initiation function, a diamine having a photosensitizing function showing a sensitizing effect by light irradiation, and a diamine having the group "-N (D)-" are preferably used. Can be done.
One or more diamines (s) used for producing the polymer (B) can be used when producing the polymer (B), and the amount used thereof is used for producing the polymer (B). It is preferably 5 to 90 mol%, more preferably 10 to 90 mol%, based on the total diamine component to be obtained.
Examples of the tetracarboxylic acid component used for producing the polymer (B) include compounds exemplified as the tetracarboxylic acid component used for producing the polyamic acid (P). Of these, the tetracarboxylic dianhydride represented by the above formula (T) or a derivative thereof is preferable.
One or more of the one represented by the above formula (T) or a derivative thereof used for producing the polymer (B) can be used in the case of producing the polymer (B), and the amount used thereof is determined. It is preferably 10 mol% or more, more preferably 20 mol% or more, based on the total tetracarboxylic acid component used in the production of the polymer (B).

The liquid crystal alignment agent of the present invention may contain other components other than the above, if necessary. Such components include, for example, a crosslinkable compound having at least one substituent selected from an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a blocked isocyanate group, a hydroxy group and an alkoxy group, and a polymerizable unsaturated group. At least one compound selected from the group consisting of crosslinkable compounds having a, functional silane compound, metal chelate compound, curing accelerator, surfactant, antioxidant, sensitizer, preservative, dielectric of liquid crystal alignment film. Examples include compounds for adjusting the rate and electrical resistance.

Preferred specific examples of the crosslinkable compound include compounds represented by any of the following formulas (CL-1) to (CL-11).

Examples of the compound for adjusting the dielectric constant and the electric resistance of the liquid crystal alignment film include monoamines having a nitrogen-containing aromatic heterocycle such as 3-picorylamine. When a monoamine having a nitrogen-containing aromatic heterocycle is used, it is preferably 0.1 to 30 parts by mass, more preferably 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. It is 20 parts by mass.

Preferred specific examples of the functional silane compound are 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, and 2-aminopropyltriethoxysilane. Silane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxy Silane, Vinyl Trimethoxysilane, Vinyl Triethoxysilane, 2- (3,4-Epoxycyclohexyl) Ethyltrimethoxysilane, 3-Glysidoxypropylmethyldimethoxysilane, 3-Glysidoxypropyltrimethoxysilane, 3-Gly Sidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldi Ethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris (3-trimethoxysilylpropyl) isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3 -Isocyanate propyltriethoxysilane and the like can be mentioned. When a functional silane compound is used, the amount used is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. It is a mass part.

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, dimethylsulfonate, 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.

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 Examples thereof include ketone (2,6-dimethyl-4-heptanone).

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. 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.

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 solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferable. It is 1 to 10% by mass. A particularly preferable solid content concentration depends on the method used when applying the liquid crystal alignment agent to the substrate. For example, in the case of the spin coating method, the solid content concentration is particularly preferably 1.5 to 4.5% by mass. In the case of the printing method, it is particularly preferable that the solid content concentration is 3 to 9% by mass and the solution viscosity is 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable to set the solid content concentration to 1 to 5% by mass and thereby the solution viscosity to 3 to 15 mPa · s.

<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 liquid crystal alignment film, and is particularly suitable for a vertically oriented type liquid crystal display element such as a VA method or a PSA mode described later. 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 (3) or steps (1) to (4).

Step (1): Step of applying the liquid crystal alignment agent on the substrate The liquid crystal alignment agent of the present invention can be applied to one surface of a substrate provided with a patterned transparent conductive film, for example, by a roll coater method, a spin coating method, or a printing method. , Apply by an appropriate coating method such as 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.

Step (2): Step of firing the coating film After the liquid crystal alignment agent is applied, preheating is preferably performed first for the purpose of preventing the applied alignment agent from dripping. The prebake temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The prebake time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Further, it is preferable that a heating (post-baking) step is carried out. The post-bake temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 5 to 300 nm, more preferably 10 to 200 nm.

The coating film formed in the above step (1) 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. The alignment ability-imparting treatment includes a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, and cotton, and photoalignment in which polarized or unpolarized radiation is applied to the coating film. Processing etc. can be mentioned.

In the photo-alignment treatment, as the radiation to irradiate the coating film, for example, ultraviolet rays including light having a wavelength of 150 to 800 nm and visible light can be used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation to be used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination thereof. When irradiating unpolarized radiation, the direction of irradiation is diagonal.

Step (3); Step of forming a liquid crystal layer (3-1) In the case of a VA type liquid crystal display element Two substrates on which a liquid crystal alignment film is formed as described above are prepared, and between the two substrates arranged opposite to each other. Place the liquid crystal display in. Specifically, the following two methods can be mentioned.
The first method is a conventionally known 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 sealing agent, and the liquid crystal composition is injected and filled into the surface of the substrate and the cell gap partitioned by the sealing agent to contact the film surface, and then the injection holes are formed. Seal.

The second method is a method called the 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.

The liquid crystal alignment agent of the present invention has a liquid crystal layer between a pair of substrates provided with electrodes, and contains a polymerizable compound that is polymerized by at least one of active energy rays and heat between the pair of substrates. Also on a liquid crystal display element (PSA type liquid crystal display element) manufactured through a step of arranging an object and polymerizing a polymerizable compound by at least one of irradiation and heating of active energy rays while applying a voltage between the electrodes. It is preferably used.
Further, the liquid crystal alignment agent of the present invention has a liquid crystal layer between a pair of substrates provided with electrodes, and a polymerizable group polymerized by at least one of active energy rays and heat between the pair of substrates. It is also preferably used for a liquid crystal display element (SC-PVA mode type liquid crystal display element) manufactured through a step of arranging a liquid crystal alignment film containing the liquid crystal alignment film and applying a voltage between the electrodes.

(3-2) In the case of a PSA type liquid crystal display element The same procedure as in (3-1) above is applied except that the liquid crystal composition containing the polymerizable compound is injected or dropped. Examples of the polymerizable compound include polymerizable compounds represented by the following formulas (M-1) to (M-7).

(3-3) In the case of SC-PVA mode type liquid crystal display element A method of manufacturing a liquid crystal display element may be adopted in the same manner as in (3-1) above and then through a step of irradiating ultraviolet rays described later. .. According to this method, a liquid crystal display element having an excellent response speed can be obtained with a small amount of light irradiation, as in the case of manufacturing the PSA type liquid crystal display element. The compound having a polymerizable group is a compound having one or more polymerizable unsaturated groups in the molecule such as an acrylate group and a methacrylate group represented by the above formulas (M-1) to (M-7). The content thereof is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of all the polymer components. Further, the polymerizable group may be contained in the polymer used for the liquid crystal aligning agent, and as such a polymer, for example, a diamine component containing a diamine having the photopolymerizable group at the end is used in the reaction. Examples thereof include the obtained polymer.

Step (4): Step of irradiating ultraviolet rays The liquid crystal cell is irradiated with light in a state where a voltage is applied between the conductive films of the pair of substrates obtained in the above (3-2) or (3-3). The voltage applied here can be, for example, a direct current or an alternating current of 5 to 50 V. Further, as the light to be irradiated, for example, ultraviolet rays containing light having a wavelength of 150 to 800 nm and visible light can be used, but ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. As the light source of the irradiation light, for example, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium hydrogen lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excima laser and the like can be used. The irradiation amount of light is preferably 1,000 to 200,000 J / m ² , and more preferably 1,000 to 100,000 J / m ² .

Then, 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 present invention will be described in more detail with reference to examples below, but the present invention is not limited thereto. The abbreviations of the compounds and the measurement method of each characteristic in the following are as follows. Further, "Me" represents a methyl group.

(Tetracarboxylic dianhydride)
BODA: Bicyclo [3.3.0] Octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

(Diamine)

(Organic solvent)
NMP: N-methyl-2-pyrrolidone, BCS: butyl cellosolve THF: tetrahydrofuran, DMF: N, N-dimethylformamide DMAc: N, N-dimethylacetamide

< ^{1 1} H-NMR measurement>
Device: Fourier transform type superconducting nuclear magnetic resonance device (FT-NMR) "AVANCE III" (manufactured by BRUKER) 500 MHz.
Solvent: Deuterated dimethyl sulfoxide ([D ₆ ] -DMSO). Standard substance: Tetramethylsilane (TMS).

<Measurement of molecular weight>
Measuring device: GPC (LC-20 series) manufactured by Shimadzu Corporation, column temperature: 50 ° C., eluent: N, N-dimethylformamide (as an additive, lithium bromide monohydrate (LiBr · H2O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, tetrahydrofuran (THF) is 10 mL / L), flow velocity: 1.0 mL / min, standard sample for preparing calibration lines: TSK standard polyethylene oxide manufactured by Toso Co., Ltd. (Molecular weight of about 900,000, 150,000, 100,000, 30,000) and Polyethylene glycol manufactured by Polymer Laboratory (molecular weight of about 12,000, 4,000, 1,000).

<Measurement of imidization rate>
20 mg of polyimide powder is placed in an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Kagaku Co., Ltd. _{), and 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d 6} , 0.05% tetramethylsilane (TMS) mixture) is added. Then, ultrasonic waves were applied to completely dissolve it. This solution was measured by proton NMR at 500 MHz with a Fourier transform type superconducting nuclear magnetic resonance apparatus (FT-NMR) “AVANCE III” (manufactured by BRUKER).

The (chemical) imidization rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and is derived from the peak integrated value of this proton and the NH group of the amic acid that appears in the vicinity of 9.5 to 10.0 ppm. It was calculated by the following formula using the integrated proton peak value. In the formula, x is the integrated proton peak value derived from the NH group of the amic acid, y is the integrated peak value of the reference proton, and α is the integrated value of the amic acid in the case of polyamic acid (imidization rate is 0%). The number ratio of the reference protons to one proton of the NH group.
Imidization rate (%) = (1-α · x / y) × 100

<Synthesis of compound (DA-1)>
Compound (DA-1) was synthesized according to the route shown below.
(Synthesis of Compound 1)

Methanol (45.0 g) was added to 5-fluoro-2-nitroanisole (15.0 g, 87.6 mmol), and methylamine (9.8 mol / L methanol solution, 89.4 mL, 876 mmol) was added at room temperature. added. After stirring for 24 hours, water (270 g) was added to precipitate crystals. After the crystals were filtered off, the crystals were washed twice with water (45 g) and dried to give compound 1 (15.3 g, 84.0 mmol, yield 95.9%).

(Synthesis of compound 2)

5-Fluoro-2-nitroanisole (7.89 g) was added to a solution containing compound 1 (8.40 g, 46.1 mmol), DMAc (84.0 g), and potassium hydroxide (3.88 g, 69.2 mmol). , 46.1 mmol) and DMAc (42.0 g) were added, and then the mixture was heated to 60 ° C. and heated and stirred for 1 hour. After completion of the reaction, water (378 g) was added to precipitate crystals. The crystals were separated by filtration, washed twice with water (50.0 g) and twice with methanol (50.0 g), and dried to obtain a crude product (17.0 g). This crude product was heated and dissolved in DMF (136 g) and then cooled, and the precipitated crystals were recovered by filtration to obtain Compound 2 (14.3 g, 42.9 mmol, yield 93.0%).

(Synthesis of DA-1)

THF (420 g) and carbon-supported palladium (5% Pd carbon powder (hydrous) K type, manufactured by NE Chemcat, 1.43 g) were added to Compound 2 (14.3 g, 42.9 mmol). Nitro reduction was performed in a hydrogen atmosphere. After completion of the reduction, the carbon-supported palladium was filtered through a membrane filter, the obtained solution was concentrated, and then isopropanol (70 g) was added to precipitate crystals. After cooling to 0 ° C., the crystals were collected by filtration, washed twice with isopropanol (30.0 g) and then dried to obtain solid DA-1 (9.6 g, 35.1 mmol, yield 82.0). %). ^{From the results of 1} H-NMR shown below, it was confirmed that the solid was DA-1.
^{1 1} H-NMR (500 MHz, [D ₆ ] -DMSO): δ = 6.52 (d, 2H, J = 8.3 Hz), 6.43 (d, 2H, J = 2.4 Hz), 6.30 (Dd, 2H, J = 8.3, 2.3 Hz), 4.29 (s, 4H), 3.66 (s, 6H), 3.07 (s, 3H)

<Synthesis of polyamic acid>
(Synthesis Example 1)
BODA (2.50 g, 10.0 mmol), DA-1 (2.19 g, 8.0 mmol), DA-4 (1.94 g, 8.0 mmol) and DA-5 (1.58 g, 4.0 mmol) Mix in NMP (32.8 g) and react at 60 ° C. for 3 hours, then add CBDA (1.90 g, 9.7 mmol) and NMP (7.6 g) and react at 40 ° C. for 4 hours to polyamic acid. The solution (1) was obtained. The number average molecular weight (Mn) of this polyamic acid was 12,100, and the weight average molecular weight (Mw) was 39,700.

(Synthesis Example 2)
BODA (2.50 g, 10.0 mmol), DA-2 (1.59 g, 8.0 mmol), DA-4 (1.94 g, 8.0 mmol) and DA-5 (1.58 g, 4.0 mmol) After mixing in NMP (30.4 g) and reacting at 60 ° C. for 3 hours, CBDA (1.90 g, 9.7 mmol) and NMP (7.6 g) are added and reacted at 40 ° C. for 4 hours to form a polyamic acid. The solution (2) was obtained. The Mn of this polyamic acid was 10,700 and the Mw was 26,600.

(Synthesis Example 3)
BODA (2.50 g, 10.0 mmol), DA-3 (1.71 g, 8.0 mmol), DA-4 (1.94 g, 8.0 mmol) and DA-5 (1.58 g, 4.0 mmol). After mixing in NMP (30.9 g) and reacting at 60 ° C. for 3 hours, CBDA (1.90 g, 9.7 mmol) and NMP (7.6 g) were added and reacted at 40 ° C. for 4 hours to form a polyamic acid. The solution (3) was obtained. The Mn of this polyamic acid was 10,500 and the Mw was 31,600.
(Synthesis Example 4)
BODA (2.50 g, 10.0 mmol), DA-6 (0.99 g, 3.0 mmol), DA-7 (1.19 g, 5.0 mmol), DA-8 (1.19 g, 6.0 mmol) and DA-9 (2.61 g, 6.0 mmol) was mixed in NMP (33.9 g), reacted at 60 ° C. for 3 hours, then CBDA (1.90 g, 9.7 mmol) and NMP (7.6 g). ) Was added and reacted at 40 ° C. for 4 hours to obtain a polyamic acid solution (4). The Mn of this polyamic acid was 11,400 and the Mw was 29,300.

The specifications of each polymer obtained in the above synthesis example are as shown in Table 1 below.

<Preparation of liquid crystal alignment agent>
(Example 1)
The liquid crystal alignment agent (A-1) was prepared by adding NMP (6.0 g) and BCS (8.0 g) to the polyamic acid solution (1) (6.0 g) obtained in Synthesis Example 1 and stirring at room temperature for 2 hours. Got
(Example 2)
NMP (6.0 g) and BCS (8.0 g) were added to the polyamic acid solution (1) (1.8 g) obtained in Synthesis Example 1 and the polyamic acid solution (4) (4.2 g) obtained in Synthesis Example 4. ) Was added and stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (A-2).

(Comparative Examples 1 and 2)
The liquid crystal alignment agents (B-1) and (B-1) of Comparative Examples 1 and 2 were used in the same manner as in Example 1 except that the polyamic acid solutions (2) and (3) were used instead of the polyamic acid solution (1), respectively. B-2) was obtained.
(Comparative Examples 3 and 4)
The liquid crystal alignment agents (B-3) and (B-3) of Comparative Examples 3 and 4 were used in the same manner as in Example 2 except that the polyamic acid solutions (2) and (3) were used instead of the polyamic acid solution (1), respectively. B-4) was obtained.

The liquid crystal alignment agents (A-1), (A-2), (B-1) to (B-4) obtained above are uniform solutions with no abnormalities such as turbidity or precipitation. It was confirmed that. Using the obtained liquid crystal alignment agent, the transmittance, the voltage retention rate, the residual DC voltage, and the afterimage characteristics were evaluated.

<Evaluation of (light) transmittance>
The liquid crystal alignment agents (A-1), (A-2), (B-1) to (B-4) obtained above are spin-coated on a quartz substrate and dried on a hot plate at 70 ° C. for 90 seconds. I let you. Then, it was fired in an IR oven at 230 ° C. for 20 minutes to form a coating film having a film thickness of 100 nm, and a substrate with a liquid crystal alignment film was obtained. This substrate with a liquid crystal alignment film was placed inside, and another quartz substrate was used to sandwich a contact liquid (manufactured by Shimadzu Device Manufacturing Co., Ltd.) for the purpose of preventing light interference. For the evaluation of the transmittance, UV-3600 (manufactured by Shimadzu Corporation) was used as a measuring device, and the temperature was 25 ° C. and the scan wavelength was 380 to 800 nm. At that time, a reference liquid was used in which a contact liquid was sandwiched between two uncoated quartz substrates. The evaluation is based on the transmittance of the wavelength of 590 nm, and the values are shown in Table 3 below.

<Manufacturing of liquid crystal display element for voltage retention / residual DC voltage evaluation>
Using the liquid crystal alignment agents (A-1), (A-2), (B-1) to (B-4) obtained above, a liquid crystal cell was produced by the procedure as shown below. The liquid crystal alignment agent was spin-coated on a glass substrate with an ITO electrode, dried on a hot plate at 70 ° C. for 90 seconds, and then baked in an IR oven at 230 ° C. for 20 minutes to form a liquid crystal alignment film having a film thickness of 100 nm. .. Two substrates with this liquid crystal alignment film are prepared, and a bead spacer with a diameter of 4 μm (manufactured by JGC Catalysts and Chemicals Co., Ltd., Shinjuku, SW-D1) is applied on the one liquid crystal alignment film, leaving the liquid crystal injection port. A thermosetting sealant (XN-1500T manufactured by Kyoritsu Kagaku Sangyo Co., Ltd.) was printed on the periphery. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was turned inside, and the cells were bonded to the previous substrate, and then the sealant was cured to prepare an empty cell.

A liquid crystal MLC-3023 (manufactured by Merck Group) was injected into this empty cell by a vacuum injection method to prepare a liquid crystal cell. Next, with a DC voltage of 15 V applied to the liquid crystal cell, UV was irradiated from the outside of the liquid crystal cell through a cut filter having a wavelength of 325 nm or less at 10 J / cm ^2. The illuminance of UV was measured using UV-MO3A manufactured by ORC. After that, for the purpose of inactivating the unreacted polymerizable compound remaining in the liquid crystal cell, UV (UV lamp: FLR40SUV32 /) was used using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation in a state where no voltage was applied. A-1) was irradiated for 30 minutes.

<Evaluation of voltage retention rate>
The voltage retention rate was measured using a liquid crystal cell for evaluating the voltage retention rate after UV irradiation. A voltage of 1 V was applied for 60 μsec in a hot air circulation oven at 60 ° C., and then the voltage after 16.67 msec was measured, and how much the voltage could be maintained was calculated as the voltage retention rate. VHR-1 manufactured by Toyo Corporation was used for measuring the voltage holding ratio. The values are shown in Table 3 below. The higher the value, the better.

<Evaluation of residual DC voltage>
A 30 Hz, 7.8 Vpp square wave with 2 V DC superimposed was applied to the liquid crystal cell for evaluating the residual DC voltage produced above at 25 ° C. for 100 hours, and the DC voltage was turned off in the liquid crystal cell 1 hour later. The residual voltage (residual DC voltage) was determined by the flicker elimination method. This value is an index of the afterimage generated by DC accumulation, and when this value is 50 mV or less, the afterimage characteristic is excellent, that is, "good", and when it is larger than 50 mV, it is defined as "bad" and evaluated. gone. The results are shown in Table 3 below.

<Manufacturing of liquid crystal display element for afterimage characteristic evaluation>
Using the liquid crystal alignment agents (A-1), (A-2), (B-1) to (B-4) obtained above, a liquid crystal cell was produced by the procedure as shown below. The liquid crystal alignment agent has an ITO electrode substrate (length: 35 mm, width: 30 mm, thickness: 0.7 mm) on which an ITO electrode pattern having a pixel size of 200 μm × 600 μm and a line / space of 3 μm is formed, and a height of 3. Spin-coat each on the ITO surface of a glass substrate with an ITO electrode (length: 35 mm, width: 30 mm, thickness: 0.7 mm) in which a 2 μm photo spacer is patterned, and 90 at 70 ° C. on a hot plate. After drying for 2 seconds, it was baked in an IR oven at 230 ° C. for 20 minutes to form a liquid crystal alignment film having a film thickness of 100 nm. The ITO electrode substrate on which this ITO electrode pattern is formed is divided into four in a cross checker (checkerboard) pattern, and can be driven separately in each of the four areas.

Next, a sealant (XN-1500T manufactured by Kyoritsu Kagaku Sangyo Co., Ltd.) was placed around the ITO electrode substrate on which an ITO electrode pattern having an ITO electrode pattern having a line / space of 3 μm coated with a liquid crystal alignment film was formed, leaving a liquid crystal injection port. ) Was printed. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was turned inside, and the cells were bonded to the previous substrate, and then the sealant was cured to prepare an empty cell. A liquid crystal MLC-3023 (manufactured by Merck Group) was injected into this empty cell by a vacuum injection method to prepare a liquid crystal cell. With a DC voltage of 15 V applied to the liquid crystal cell, UV was irradiated from the outside of the liquid crystal cell through a cut filter of 325 nm or less at 10 J / cm ^2. The illuminance of UV was measured using UV-MO3A manufactured by ORC. After that, for the purpose of inactivating the unreacted polymerizable compound remaining in the liquid crystal cell, UV (UV lamp: FLR40SUV32 /) was used using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation in a state where no voltage was applied. A-1) was irradiated for 30 minutes.

<Evaluation of afterimage characteristics>
Using the liquid crystal cell for evaluating afterimage characteristics prepared above, an AC voltage of 60 Hz and 20 Vp-p was applied to two diagonal areas out of the four pixel areas, and the product was driven at a temperature of 25 ° C. for 168 hours. .. After that, all four pixel areas were driven by an AC voltage of 5 Vp-p, and the difference in the brightness of the pixels was visually observed. The state in which the difference in luminance could hardly be confirmed was defined as "good", and the state in which the difference in luminance could be easily confirmed was defined as "poor" and evaluated. The results are shown in Table 3 below.

As shown in Table 3, the liquid crystal alignment film obtained by using the liquid crystal alignment agent (A-1) of Example 1 corresponds to the liquid crystal alignment agents (B-1) and (B-2) of Comparative Examples 1 and 2. ), High transmittance was obtained as compared with the liquid crystal alignment film obtained by using. Further, the liquid crystal alignment film obtained by using the liquid crystal alignment agent (A-2) of Example 2 can be obtained by using the corresponding liquid crystal alignment agents (B-3) and (B-4) of Comparative Examples 3 and 4. Higher transmittance was obtained as compared with the liquid crystal alignment film. The difference of 0.5% in the transmittance is a remarkable difference in the art.
Further, it can be seen that when the liquid crystal alignment agent obtained in the examples is used, a liquid crystal alignment film having a high voltage retention rate can be obtained even in the voltage retention evaluation. Further, it can be seen that a liquid crystal alignment film showing good characteristics can be obtained in the evaluation of the residual DC voltage and the evaluation of the afterimage characteristics.

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is, for example, a watch, a portable game, a word processor, a notebook computer, a car navigation system, a camcoder, a PDA, a digital camera, a mobile phone, a smartphone, various monitors, a liquid crystal television, and the like. It can be widely applied to information displays and the like, especially to ultra-high-definition liquid crystal displays such as 4K and 8K.

The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2020-12086 filed on July 14, 2020 are cited here and incorporated as the disclosure of the specification of the present invention. Is.

Claims

It contains at least one polymer (P) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (1) represented by the following formula (1) and a polyimide which is an imidized product thereof. A liquid crystal alignment agent characterized by that.

(R represents a monovalent organic group, and R 1 and R 2 are each saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms or an alicyclic having 3 to 6 carbon atoms. The formula represents a hydrocarbon group. A part of the hydrogen atom of the hydrocarbon group in R 1 and R 2 may be substituted.)
In the formula (1), R is a monovalent organic group having an aromatic ring structure, a monovalent chain hydrocarbon group having 1 to 30 carbon atoms, or a monovalent alicyclic hydrocarbon having 3 to 30 carbon atoms. It is a group, and a part of the hydrogen atom of the chain hydrocarbon group or the alicyclic hydrocarbon group may be substituted, and a part of the methylene group having the group may be an oxygen atom, a carbonyl group or -COO. The liquid crystal alignment agent according to claim 1, which may be substituted with-.
The liquid crystal alignment agent according to claim 2, wherein the monovalent organic group having an aromatic ring structure in R has a structure represented by the following formula (Ar).

( Ra represents a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or a fluoroalkyl group having 1 to 9 carbon atoms. M is 0 to 5 is an integer, when m is 2 to 5, with. * is the definition plurality of R a independently represents a bond.)
In the formula (1), R, R 1 and R 2 are independently methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group and tert-. The liquid crystal alignment agent according to any one of claims 1 to 3, which is a butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group or a tert-pentyl group.
The liquid crystal alignment agent according to any one of claims 1 to 4, wherein the diamine (1) is any diamine selected from the group consisting of the following formulas (d-1) to (d-4).
A claim obtained by using a diamine component containing a diamine (s) having at least one structure selected from the group consisting of the following formulas (S1), (S2) and (S3). Item 6. The liquid crystal alignment agent according to any one of Items 1 to 5.

(X 1 and X 2 are independent, single bond,-(CH 2 ) a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH 3 )- , -N (CH 3 ) CO-, -NH-, -O-, -COO-, -OCO- or-((CH 2 ) a1- A 1 ) m1- (a1 is an integer of 1 to 15 and A 1 represents an oxygen atom or -COO-, m 1 is an integer of 1 or 2, and a plurality of a 1 and A 1 when m 1 is 2 may be the same or different. Good). G 1 and G 2 are divalent, independently selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Represents a cyclic group. Any hydrogen atom on the cyclic group may be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, or 1 to 3 carbon atoms. May be substituted with at least one selected from the group consisting of a fluorine-containing alkoxy group and a fluorine atom. M and n are independently integers of 0 to 3, and the sum of m and n is 1. When there are a plurality of m and n, the plurality of X 1 , X 2 , G 1 and G 2 may be the same or different. R 1 has 1 to 20 carbon atoms. Any hydrogen atom representing an alkyl group, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms and forming R 1 may be substituted with a fluorine atom.)

(X 3 is a single bond, -CONH-, -NHCO-, -CON (CH 3 )-, -N (CH 3 ) CO-, -NH-, -O-, -CH 2 O-, -COO- Alternatively, it represents —OCO—, where R 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming R 2 may be substituted with a fluorine atom. .)

(X 4 represents -CONH-, -NHCO-, -O-, -CH 2 O-, -OCH 2- , -COO- or -OCO-. R 3 represents a structure having a steroid skeleton.)
The liquid crystal alignment agent according to claim 6, wherein the diamine (s) is a diamine represented by the following formula (d1) or formula (d2).

(X is a single bond, -O-, -C (CH 3 ) 2- , -NH-, -CO-, -COO-, -CONH-,-(CH 2 ) m- , -SO 2 -,- O- (CH 2) m -O - , - O-C (CH 3) 2 -, - CO- (CH 2) m -, - CO- (CH 2) m -CO -, - NH- (CH 2 ) m -, - NH- (CH 2) m -NH -, - SO 2 - (CH 2) m -, - SO 2 - (CH 2) m -SO 2 -, - CONH- (CH 2) m - , -CONH- (CH 2 ) m -NHCO-, or -COO- (CH 2 ) m- OCO- represents a divalent organic group. M is an integer of 1-8. Y is the above formula ( Represents any of the structures S1) to (S3). In the formula (d2), the two Ys may be the same or different from each other.)
The liquid crystal alignment agent according to claim 7, wherein the diamine represented by the formula (d1) is any diamine selected from the group consisting of the following formulas (d1-1) to (d1-18).

(N is an integer from 1 to 20.)
The liquid crystal alignment agent according to claim 7, wherein the diamine represented by the formula (d2) is any diamine selected from the group consisting of the following formulas (d2-1) to (d2-6).

(X p1 to X p8 are independently each of-(CH 2 ) a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH 3 )-,-. N (CH 3 ) represents CO-, -NH-, -O-, -CH 2 O-, -CH 2 OCO-, -COO-, or -OCO-. X s1 to X s4 are independent of each other. -O-, -CH 2 O-, -COO- or -OCO-. X a to X f are single bonds, -O-, -NH-, or -O- (CH 2 ) m- O- (M is an integer of 1 to 8). R 1a to R 1h independently represent an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or 2 to 20 carbon atoms. Represents the alkoxyalkyl group of.)
Claims 1 to 1 obtained by a polymerization reaction of the polymer (P) with the diamine component and a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (T) or a derivative thereof. 9. The liquid crystal aligning agent according to any one of 9.

(X represents any structure selected from the group consisting of the following formulas (x-1) to (x-13).)

(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. Represents a monovalent organic group or phenyl group having 1 to 6 carbon atoms. R 5 and R 6 independently represent a hydrogen atom or a methyl group. J and k are integers of 0 or 1. There, A 1 and A 2 are each independently a single bond, ether (-O-), carbonyl (-CO-), ester (-COO-), a phenylene group, a sulfonyl group (-SO 2 -) or an amide group (-CONH-), 2 pieces of a 2 may be the same or may be different. * 1 is a bond that binds to one of the anhydride groups, * 2 and the other It is a bond that binds to the acid anhydride group of.)
The liquid crystal alignment agent according to claim 10, wherein X in the formula (T) is any one of (x-1) to (x-7) and (x-11) to (x-13).
The liquid crystal alignment agent according to any one of claims 1 to 11, wherein the diamine (1) is contained in an amount of 1 to 100 mol% in the total diamine component.
The liquid crystal alignment agent according to any one of claims 6 to 12, wherein the diamine (s) is contained in an amount of 1 to 99 mol% in the total diamine component.
The liquid crystal alignment agent is at least one selected from the group consisting of a polyimide precursor obtained by further using a diamine component containing no diamine (1) and a tetracarboxylic acid component, and a polyimide which is an imidized product of the polyimide precursor. The liquid crystal alignment agent according to any one of claims 1 to 13, which contains the polymer (B) of the species.
A liquid crystal alignment film for vertical alignment formed by using the liquid crystal alignment agent according to any one of claims 1 to 14.
A liquid crystal display element provided with the liquid crystal alignment film according to claim 13.
The liquid crystal alignment agent according to any one of claims 1 to 14 is applied onto a pair of substrates having a conductive film to form a coating film, so that the coating films face each other via a layer of liquid crystal molecules. A method for manufacturing a liquid crystal display element, which forms a liquid crystal cell so as to face each other and irradiates the liquid crystal cell with light in a state where a voltage is applied between the conductive films of the pair of substrates.