WO2021199974A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

The present invention addresses the problem of providing: a liquid crystal alignment agent which makes it possible to produce a liquid crystal alignment film having excellent film hardness at low cost; and a liquid crystal display element equipped with the liquid crystal alignment film. Further provided is a liquid crystal alignment agent which makes it possible to produce a liquid crystal alignment film and a liquid crystal display element which are superior in various properties other than film hardness.　The liquid crystal alignment agent is characterized by comprising a component (A).　Component (A): at least one polymer (A) selected from the group consisting of a (polyimide precursor)-polyurea copolymer having a repeating unit represented by formula (m1) and a repeating unit represented by formula (1) and an imidized polymer of the copolymer, in which at least one of the repeating unit represented by formula (m1) and the repeating unit represented by formula (1) is derived from an aromatic diamine (a) having any one of the structures respectively represented by formulae (S1) to (S2), and the polymer (A) can be produced without using an aliphatic diamine. (The meaning of each of the substituents 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 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 to be used have been developed. For example, TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, and VA (Vertical Organic) ) Type, IPS type (In-Plane Switching) type, FFS (Fringe Field Switching) type and various display elements are known. These liquid crystal display elements have 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.
In the VA type liquid crystal display element, which is one of the driving methods of the liquid crystal display element, as a technique for increasing the response speed of the liquid crystal, a photopolymerizable compound is added to the liquid crystal composition in advance, and the liquid crystal is provided with a polyimide liquid crystal alignment film. A PSA (Polymer Sustained Alignment) type liquid crystal display element (see, for example, Patent Document 1 and Non-Patent Document 1) that irradiates a cell with ultraviolet rays while applying a voltage has been proposed.

In recent years, large-screen, high-definition LCD TVs have become the mainstream, and small display terminals such as smartphones and tablet PCs have become widespread, and the demand for higher quality LCD display elements has increased even more than before. .. Against this background, various liquid crystal alignment agents have been proposed in order to improve the performance of the liquid crystal alignment film and improve various characteristics of the liquid crystal display element (for example, liquid crystal orientation, voltage retention, etc.) (for example, various liquid crystal alignment agents). For example, see Patent Document 2).
In addition to the above properties, it is also required that the film hardness is high. When a liquid crystal alignment film having a low film hardness is used in the liquid crystal display element, the film is scraped in the manufacturing process of the liquid crystal display element, and the liquid crystal is misaligned at the scraped portion, resulting in bright spots and deterioration of display quality. do. In recent years, touch panel displays have become widespread in addition to the manufacturing process, and high film hardness is required to prevent film scraping due to touch panel operation. As a means for solving the above problems, Patent Document 3 proposes a polyimide-based liquid crystal aligning agent obtained by using a specific tetracarboxylic acid dianhydride having a carbon-carbon triple bond.

Japanese Unexamined Patent Publication No. 2003-307720 WO2014 / 126102 Japanese Unexamined Patent Publication No. 2019-014837

When the present inventor produced a liquid crystal alignment film using the method described in Patent Document 2, it became clear that the film hardness of the obtained alignment film was low. It is also possible to prepare a liquid crystal alignment film by using the method described in Patent Document 3, but since it is necessary to newly synthesize a tetracarboxylic acid dianhydride, the cost of a liquid crystal alignment agent using this is required. There was a demerit that it became high.

An object of the present invention is to provide a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film having excellent film hardness at low cost, and a liquid crystal display element provided with the liquid crystal alignment film. Another object of the present invention is to provide a liquid crystal alignment film and a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film and a liquid crystal display element having various properties other than film hardness.

As a result of diligent research to achieve the above object, the present inventor has found that a liquid crystal aligning agent containing a specific component is effective for achieving the above object, and completes the present invention. It came to.

The present invention is based on such findings, and the gist of the present invention is as follows.
A liquid crystal alignment agent containing the following component (A).
Component (A): Selected from the group consisting of a polyimide precursor-polyurea copolymer having a repeating unit represented by the following formula (m1) and a repeating unit represented by the following formula (1) and an imidized polymer thereof. At least one of the polymer (A), the repeating unit represented by the above formula (m1) and at least one of the repeating units represented by the above formula (1) are the following formulas (S1) to (S2). ) Is derived from the aromatic diamine (a) having any of the structures represented by), and the above-mentioned polymer (A) can be obtained without using an aliphatic diamine.

(X ₁ is .Y ₁ .2 one R ₁ representing a divalent organic radical derived from an aromatic diamine represents a tetravalent organic group, each independently, a hydrogen atom or an alkyl having 1 to 5 carbon atoms .2 pieces of Z ₁ represents a group independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, alkenyl optionally having 2 to 10 carbon atoms which may have a substituent Represents an alkynyl group having 2 to 10 carbon atoms, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group which may have a group or a substituent.

(A ₁ is a divalent organic group, A ₂ is a divalent organic group derived from an aromatic diamine, and C ₁ and C ₂ are independently hydrogen atoms or alkyl having 1 to 3 carbon atoms. It is a group.)

(X ¹ and X ² are independent, single bond,-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N (CH). ₃ )-, -NH-, -O-, -COO-, -OCO- or-((CH ₂ ) _a1- A ₁ ) _m1- . Of these, a1 is an integer of 1 to 15, and A ₁ represents an oxygen atom or -COO-, and m ₁ is an integer of 1 to 2. G ¹ and G ² are independently divalent aromatic groups having 6 to 12 carbon atoms and carbon. Represents a divalent cyclic group selected from the divalent alicyclic groups of numbers 3-8. Any hydrogen atom on the cyclic group may be substituted. M and n are 0 independently of each other. It is an integer of 3 to 3, and m + n is 1 to 6, preferably 1 to 4. R ¹ is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or 2 to 20 carbon atoms. Any hydrogen atom forming R ¹ may be substituted with a fluorine atom. ^{If a plurality of X 1} , X ² , G ¹ , G ² , a 1 and A 1 are present, the plurality is present. X ¹ , X ² , G ¹ , G ² , a1 and A1 have the above definitions independently.)

(X ^2a represents -CONH-, -NHCO-, -O-, -CH ₂ ^{O-, -COO- or -OCO-. R 2} represents a structure having a steroid skeleton.)

According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment film and a liquid crystal display element having excellent film hardness can be obtained at low cost. Furthermore, according to the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment film and a liquid crystal display element having various properties other than film hardness.
The mechanism by which the above effects of the present invention are obtained is not always clear, but by using aromatic diamine as a constituent component of the polymer, the obtained polymer can form stacking between aromatic rings, and urea. It is considered that one of the reasons is that many hydrogen bonds can be formed in the membrane because the molecule has a bond.

As used herein, the term "aromatic diamine" refers to a diamine in which at least one amino group is directly bonded to an aromatic ring, and an aliphatic group may be contained as part of the structure thereof.
The "aliphatic diamine" refers to a diamine in which two amino groups are directly bonded to an aliphatic group, and an aromatic group may be contained as a part of the structure thereof.
Aliphatic groups include both acyclic aliphatic groups and cyclic aliphatic groups (aliphatic groups).
In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure, and other components optionally blended will be described.
<Polymer (A)>
The liquid crystal aligning agent of the present invention is a group consisting of a polyimide precursor-polyurea copolymer composed of a repeating unit represented by the above formula (m1) and a repeating unit represented by the above formula (1), and an imidized polymer thereof. At least one polymer (A) selected from the above, and at least one of the repeating units of the polymer (A) is an aromatic having a structure represented by the above formulas (S1) to (S2). Derived from the diamine (a), the polymer (A) can be obtained without using an aliphatic diamine.

(Aromatic diamine (a))
At least one of the repeating unit represented by the formula (m1) and the repeating unit represented by the above formula (1) is an aromatic diamine having any of the structures represented by the above formulas (S1) to (S2). Derived from (a). The aromatic diamine (a) is preferably an aromatic diamine having a structure represented by the above formulas (S1) to (S2) in the side chain.

Specific examples of the structures represented by the above formulas (S1) to (S2) include structures represented by the following formulas (S1-1) to (S1-7) and (S2-a). In the formula (S2-a), X represents the formula (X1), the formula (X2) or -CH ₂ O-, and Col is the formula (Col-1), the formula (Col-2) or the formula (Col-2). Col-3), where G represents formula (G1), formula (G2), formula (G3) or formula (G4). * Represents a bond.

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

The aromatic diamine (a) preferably has at least one benzene ring. More preferably, it is an aromatic diamine having 6 to 50 carbon atoms. Specific examples of the aromatic diamine (a) include diamines represented by the following formula (d1) or formula (d2).

(X is a single bond, -O-, -C (CH ₃ ) _2- , -NH-, -CO-,-(CH ₂ ) _m- , -SO _2- , -O- (CH ₂ ) _{m- O -, - O-C (} CH 3) 2 -, - CO- (CH 2) m -, - NH- (CH 2) m -, - SO 2 - (CH 2) m -, - CONH- (CH _{2) m -, - CONH- (} CH 2) m -NHCO-, or -COO- _{(CH 2)} .m representing a divalent organic group m -OCO- is an integer of 1 ~ 8 .Y is , Represents the structure of any of the above formulas (S1) to (S2). In the above formula (d2), the two Ys may be the same or different from each other.)

Preferred examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-6). Preferred examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6).

(X ^v1 to X ^v4 and X ^p1 to X ^p8 are independently- (CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, and -CO-N ( CH ₃ )-, _{-NH-, -O-, -CH 2} O-, -CH _2- OCO-, -COO-, or -OCO-, where X ^V5 to X ^V6 and X ^s1 to X ^s4 are They independently represent -O-, -CH ₂ O-, -COO- or -OCO-. X _a to X _f are independently single-bonded, -O-, -NH-, or -O-, respectively. (CH ₂ ) represents _m- O- (m is an integer of 1 to 8), and R ^v1 to R ^v4 and R ^1a to R ^1h are independent of each other, -C _n H _{2n + 1} (n is an integer of 1 to 20). , -OC _n H _{2n + 1} (n represents an integer of 2 to 20)

The repeating unit of the polymer (A) may be derived from an aromatic diamine other than the aromatic diamine (a) (hereinafter, also referred to as “other aromatic diamine”). Specific examples of other aromatic diamines include p-phenylenediamine, m-phenylenediamine, 4- (2- (methylamino) ethyl) aniline, 2,4-diaminobenzoic acid, and 2,5-diaminobenzoic acid. 3,5-Diaminobenzoic acid, or diamines having a carboxy group such as diamine compounds represented by the following formulas (3b-1) to (3b-4), 4,4'-diaminodiphenylmethane, 3,3'-diamino Diphenylmethane, 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) benzene, 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) Pentan, 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, 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, light such as 2- (2,4-diaminophenoxy) ethyl methacrylate, 2,4-diamino-N, N-diallylaniline and the like. Diamine having a polymerizable 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 (4) -Aminophenyl) Fluole Diamine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl, which have a photosensitizing effect when irradiated with light such as -3,6-diaminocarbazole, diamines having heterocycles such as the following formulas (z-1) to (z-18), diamines having a diphenylamine skeleton such as the following formulas (Dp-1) to (Dp-9), Groups such as the following formulas (5-1) 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 tert-butoxycarbonyl group. ), And aromatic diamines having 6 to 30 carbon atoms such as diamines having an oxazoline structure such as the following formulas (Ox-1) to (Ox-2), but are not limited thereto.

(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-, -CO- N (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 (3b). In -2), m ³ and m ⁴ independently represent integers of 1 to 5. In formula (3b-3), A ² represents a linear or branched alkyl group having 1 to 5 carbon atoms. m5 is an integer of 1 to 5 formula in (3b-4), independently ^{a 3} and ^{a 4} are each 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 -, - CO-N (CH 3) - or _-N (CH 3) -CO- indicates, m6 is an integer of 1 to 4).

(N is an integer from 1 to 6.)

(Boc represents a tert-butoxycarbonyl group.)

The above 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, the diamine having a photopolymerizable group at the end, the diamine represented by the above formulas (R1) to (R5), the above formula (z-1) to The diamine represented by (z-18) is used alone or in combination of two or more when producing the polymer (A) from the viewpoint of increasing the response speed of the liquid crystal display element using the PSA method or the SC-PVA mode. May be good.

Among the other aromatic diamines, p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-, among the above, from the viewpoint of preferably obtaining the effects of the present invention. Diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2- (2,4-diaminophenoxy) ethyl methacrylate, 2,4-diamino-N, N-diallylaniline, the above formula (R1). The diamine represented by (R5), the diamine represented by the above formulas (z-1) to (z-18), the diamine represented by the above formulas (Dp-1) to (Dp-9), the above formula. Diamines represented by (Ox-1) to (Ox-2) are preferable.

(Repeating unit represented by equation (m1))
In the above formula (m1), Y ₁ represents a divalent organic group derived from an aromatic diamine. Examples of the aromatic diamine include the above-mentioned aromatic diamine (a) and the above-mentioned other aromatic diamines.
_{At least one of Y 1} of the above formula (m1) _{and A 2} of the above formula (1) represents a divalent organic group derived from the aromatic diamine (a).

In the above formula (m1), X ₁ represents a tetravalent organic group. X ₁ is preferably a tetravalent organic group derived from tetcarboxylic dianhydride or a derivative thereof. Examples of the tetravalent organic group include a tetravalent organic group derived from an aliphatic tetcarboxylic acid dianhydride or a derivative thereof, and a tetravalent organic group derived from an alicyclic tetracarboxylic acid dianhydride or a derivative thereof. Alternatively, a tetravalent organic group derived from aromatic tetracarboxylic dianhydride or a derivative thereof can be mentioned. X ₁ is preferably a tetravalent organic group derived from a tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof.

(X represents a structure selected from any 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. Yes, A ₁ and 2 A ₂ independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide group. * 1 is one acid anhydride. a bonding hand bonded to the group, * 2 is a bond that binds to the other acid anhydride groups. in the above formula (x-13), the two a _2, are being the same or different May be.)

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). In the formula, * represents a bond.

As a preferable example of the tetracarboxylic dianhydride represented by the above formula (3) or a derivative thereof, X is the above formulas (x-1) to (x-7), (x-11) to (x-13). ), The tetracarboxylic dianhydride represented by the formula (3) or a derivative thereof can be mentioned.

In the above formula (m1), 2 pieces of R ₁ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably represents a hydrogen atom or a methyl group.
In the above formula (m1), 2 pieces of Z ₁ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, which may 2 carbon atoms have a substituent It represents an alkenyl group of 10, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group, preferably a hydrogen atom or a methyl group. ..
In the above formula (m1), each of X ₁ , Y ₁ , R ₁ , and Z ₁ may be one type or two or more types.

(Repeating unit represented by equation (1))
In the above formula (1), A ₁ is a divalent organic group. A ₁ is preferably a divalent organic group derived from diisocyanate. Examples of A ₁ include a divalent aromatic group having 6 to 30 carbon atoms and a divalent aliphatic group having 4 to 30 carbon atoms or an alicyclic group having at least one benzene ring. Specific examples of A ₁ include o-phenylenediisocyanate, m-phenylenediocyanate, p-phenylenediocyanate, toluenediisocyanates (for example, trilene 2,4-diisosocyanate), 1,4-diisocyanate-2-methoxybenzene, and the like. Xylenes 2,5-diisocyanate, 2,2'-bis (phenyl 4-diisocyanate) propane, 4,4'-diphenylmethane diisosocyanate, 4,4'-diphenyl ether diisosocyanate, diphenyl 4,4'-diisocyanate Divalent organic groups derived from aromatic diisocyanates such as sulfones, diphenylsulfone 3,3'-diisosocyanate and benzophenone 2,2'-diisocyanate, acyclic fats such as isophorone diisocyanate, hexamethylene diisocyanate and tetramethylene diisocyanate. Divalent organic groups derived from group or alicyclic diisocyanates can be mentioned. Among them, A ₁ is preferably a divalent organic group derived from trilene 2,4-diisosocyanate from the viewpoint of availability, polymerization reactivity, and voltage retention.

In the above formula (1), A ₂ is a divalent organic group derived from an aromatic diamine. Examples of the aromatic diamine include the above-mentioned aromatic diamine (a) and the above-mentioned other aromatic diamines.

_{At least one of Y 1} of the above formula (m1) _{and A 2} of the above formula (1) represents a divalent organic group derived from the above aromatic diamine (a).
In the above formula (1), C ₁ and C ₂ are independently hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, preferably hydrogen atoms or methyl groups.
In the above formula (1), A ₁ , A ₂ , C ₁ , and C ₂ may each have one type or two or more types.

(Repeating unit constituting the polymer (A))
The polymer (A) in the present invention has a repeating unit represented by the above formula (m1) and a repeating unit represented by the above formula (1). The polymer (A) may have a repeating unit represented by the above formula (m1), a repeating unit represented by the above formula (1), and a terminal group. The polymer (A) has an arbitrary repeating unit (hereinafter, also referred to as other repeating unit) other than the repeating unit represented by the above formula (m1) and the repeating unit represented by the above formula (1). However, it is preferably composed of a repeating unit represented by the above formula (m1), a repeating unit represented by the above formula (1), and a terminal group.

Here, the terminal group means a group bonded to the end of the repeating unit constituting the polymer (A). Examples of the terminal group include an amino group, a carboxy group, an acid anhydride group, an isocyanate group or a derivative thereof. The amino group, carboxy group, acid anhydride group and isocyanate group can be obtained by a usual condensation reaction, and the above derivative can be obtained by modifying the terminal group with, for example, a terminal modifier, as described later.

The polymer (A) can be obtained without using an aliphatic diamine. Therefore, the polymer (A) does not contain a group derived from an aliphatic diamine. That is, the repeating unit represented by the above formula (m1) and the repeating unit represented by the above formula (1) do not contain a group derived from an aliphatic diamine. Similarly, the other repeating units mentioned above do not contain groups derived from aliphatic diamines.

The content ratio of the repeating unit represented by the formula (m1) is preferably 10 to 90 mol%, more preferably 25 to 75 mol% of the total of the repeating units constituting the polymer (A).
The content ratio of the repeating unit represented by the formula (1) is preferably 10 to 90 mol%, more preferably 25 to 75 mol% of the total of the repeating units constituting the polymer (A).
Further, the repeating unit above Y ₁ is represented by a divalent organic group derived from the aromatic diamine (a) (m1), a divalent to the A ₂ is derived from the aromatic diamine (a) The total of the repeating units represented by (1), which is the organic group of the above, is preferably 10 to 90 mol%, more preferably 10 to 85 mol% of the total of the repeating units constituting the polymer (A).

<Polymer (B)>
From the viewpoint of enhancing electrical properties, the liquid crystal alignment agent of the present invention is at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer thereof, and is different from the polymer (A). (B) may be further contained. In particular, the liquid crystal orientation can be enhanced by further containing the polymer (B).
The polymer (B) is preferably at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit represented by the following formula (m2) and an imidized polymer thereof.

(X ₂ represents a tetravalent organic group. Y ₂ represents a divalent organic group. R ₂ and Z _{2 are synonymous with R 1} and Z ₁ of the formula (m1), respectively, and two. R ₂ and Z ₂ may be the same or different from each other.)

The polymer (B) preferably does not have a repeating unit represented by the above formula (1).
The tetravalent organic group in X _2, aliphatic Tetokarubon dibasic derived anhydrides tetravalent organic group, tetravalent organic group or an aromatic tetracarboxylic acid derived from an alicyclic tetracarboxylic acid dianhydride Examples thereof include a tetravalent organic group derived from a dianoxide, and specific examples thereof include a tetravalent organic group exemplified by _{X 1 of the above formula (m1).} From the viewpoint of efficiently obtaining the effects of the present invention, tetravalent organic groups represented by the above formulas (x-1) to (x-13) (collectively referred to as specific tetravalent organic groups). ) Is preferable.

From the viewpoint of efficiently obtaining the effects of the present invention, the _{polymer (B) contains a repeating unit in which X 2} is the above-mentioned specific tetravalent organic group in an amount of 5 mol% of all the repeating units contained in the polymer (B). It is preferably contained in an amount of 10 mol% or more, and more preferably contained in an amount of 10 mol% or more.
The polymer (B) is _{a repeating unit in which X 2} is the above formulas (x-1) to (x-11) and X ₂ is a repeating unit in the above formulas (x-12) to (x-13). It is preferable to have a unit.

Specific examples of Y ₂ include a divalent organic group derived from the aromatic diamine exemplified in the above polymer (A), and an organo such as 1,3-bis (3-aminopropyl) -tetramethyldisiloxane. Examples thereof include a divalent organic group derived from a siloxane-containing diamine. From the viewpoint of enhancing electrical properties, the polymer (B) is _{a diamine in which Y 2} has a nitrogen atom-containing structure, and 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2, 4-Diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid and the above formulas (3b-1) to (3b-4). ) Is a diamine organic group obtained by removing two amino groups from a diamine selected from diamines having a carboxy group such as a diamine compound (these are also collectively referred to as a specific divalent organic group). It is preferably a polymer containing a unit.

From the viewpoint of enhancing the electrical properties, the polymer (B) may contain 1 mol% or more of the repeating units in which _{Y 2 is the specific divalent organic group described above in the polymer (B).} It may contain 5 mol% or more.

From the viewpoint of enhancing the electrical characteristics, the content ratio of the component (A) and the component (B) may be 10/90 to 90/10 in terms of the mass ratio of [(A) component] / [(B) component]. , 20/80 to 90/10, or 20/80 to 80/20.

<Production of polymer (A) and polymer (B)>
The polyimide precursor-polyurea copolymer which is the polymer (A) is, for example, a component (a) containing a compound containing two isocyanate groups in the molecule and a primary or secondary polymer in the molecule. It can be produced by reacting a component (b) containing a compound containing two amino groups with a component (c) containing a tetracarboxylic dianhydride or a derivative thereof.
The component (a), the component (b) and the component (c) may each have one type or two or more types.

Examples of the component (a) include compounds represented by O = C = N—A ₁ −N = C = O (A ₁ is the same as _{A 1} in the formula (1)).

Examples of the component (b) include compounds represented by the following formula [b].

(Wherein _{[b], C 1, C} 2, A 2 is the same as _{C 1, C 2, A} 2 in the formula (1).)
Specific examples of the compound represented by the above formula [b] include the above aromatic diamine (a) and the above other aromatic diamines.

The component (b) is, for example, at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding the imide ring of polyimide), a secondary amino group and a tertiary amino group. It may contain an aromatic diamine having. However, the component (b) does not contain an aliphatic diamine.

Examples of the nitrogen atom-containing heterocycle include pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indol, benzimidazole, purine, quinoline, isoquinoline, naphthylene, quinoxaline, phthalazine, triazine, carbazole, and acrydin. Examples thereof include piperidine, piperazine, pyrrolidine, benzimidazole imine and the like. Of these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole or acridine are preferable.

The secondary amino group and the tertiary amino group that the diamine having a nitrogen atom-containing structure may have are represented by, for example, the following formula (n).

In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "*" Represents a bond that binds to a hydrocarbon group.

Examples of the monovalent hydrocarbon group of R in the above formula (n) include an alkyl group such as a methyl group, an ethyl group and a propyl group; a cycloalkyl group such as a cyclohexyl group; and an aryl such as a phenyl group and a methylphenyl group. The group etc. can be mentioned. R is preferably a hydrogen atom or a methyl group.

Specific examples of the diamine having a nitrogen atom-containing structure include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, and N-methyl-3,6. -Diaminocarbazole, diamines represented by the above formulas (z-1) to (z-18), and diamines represented by the above formulas (Dp-1) to (Dp-9) can be mentioned.

Examples of the tetracarboxylic dianhydride or its derivative contained in the component (c) include the tetracarboxylic dianhydride represented by the above formula (3) or its derivative.

The tetracarboxylic dianhydride represented by the formula (3) or a derivative thereof is preferably 1 mol% or more of the total component (c). More preferably, it is 5 mol% or more, and particularly preferably 10 mol% or more.

The reaction of the component (a), the component (b) and the component (c) is usually carried out in an organic solvent. The organic solvent used at that time is not particularly limited as long as it dissolves the produced polyimide precursor-polyurea copolymer. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-. Butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethylamyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellsolve, ethyl cellsolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, Ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol , Diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate Monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone , Methylcyclohexene, propyl ether, dihexyl ether, 1,4-dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, Ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate , Examples thereof include 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination. Further, even if the solvent does not dissolve the polyimide precursor, it may be mixed with the above solvent and used as long as the produced polyimide precursor does not precipitate. Further, since the water content in the organic solvent inhibits the polymerization reaction and further causes the produced polyimide precursor to be hydrolyzed, it is preferable to use a dehydrated and dried organic solvent.

Examples of the order in which the component (a), the component (b) and the component (c) are reacted include a method in which the component (a) and the component (b) are reacted and then the component (c) is added and reacted. Be done. By reacting in this way, in the obtained polyimide precursor having the repeating unit represented by the formula (m1), the repeating unit represented by the formula (1) and the repeating unit represented by the formula (m1) were randomly bonded. It is preferable because it becomes a random copolymer.

On the other hand, a step of reacting the component (a) and the component (b) to obtain a urea-based polymer composed of a repeating unit represented by the formula (1), and a step of reacting the component (b) and the component (c) to the formula (c). It has a step of obtaining a polyimide precursor composed of the repeating unit represented by m1), and then from the obtained urea polymer composed of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (m1). In the method of reacting with the polyimide precursor, the obtained polymer having a repeating unit represented by the formula (1) has a structure like a block copolymer of polyurea and the polyimide precursor, that is, the above random common weight. The polymer structure is composed of a urea-based polymer and a polyimide precursor, which have a higher degree of polymerization as compared with the coalesced polymer.

The temperature at which the component (a), the component (b) and the component (c) are reacted can be selected from any temperature of −20 to 150 ° C., but is preferably in the range of −5 to 100 ° C. In addition, the reaction can be carried out at any concentration. The total concentration of the component (a), the component (b) and the component (c) is preferably 1 to 50% by mass, more preferably 5 to 30% by mass in the reaction solution. The initial reaction can be carried out at a high concentration, after which an organic solvent can be added. Twice

The ratio of the component (a), the component (b) and the component (c) to be reacted is, for example, the total amount of the component (a) and the component (c) in a molar ratio: component (b) = 0.8: 1. It is preferably ~ 1.2: 1. The ratio of the component (a) to the total amount of the component (a) and the component (c) is preferably 20 to 60 mol%.

Examples of the polyimide precursor which is the polymer (B) include polyamic acid and polyamic acid ester. The polyimide precursor which is the polymer (B) can be synthesized by a known method as described in, for example, International Publication WO2013 / 157586. The diamine component for producing the polyimide precursor which is the polymer (B) is composed of a nitrogen atom-containing heterocycle (excluding the imide ring of the polyimide), a secondary amino group and a tertiary amino group. It may contain a diamine having at least one nitrogen atom-containing structure selected from the group. An example of the nitrogen atom-containing structure is as described in the above description of the polymer (A).

[Terminal modifier]
When synthesizing the polymers (A) and (B) in the present invention, a terminal-modified polymer is used together with a tetracarboxylic acid derivative component, a diamine component, and optionally a diisocyanate component as described above, using an appropriate terminal modifier. May be synthesized.

Examples of the terminal modifier include acetic anhydride, maleic anhydride, nadic acid anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic anhydride, trimetic acid anhydride, and the following formula (m-). 1) Compounds represented by (m-6), 3- (3-trimethoxysilyl) propyl) -3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroiso Acid monoanhydrides such as benzofuran-1,3-dione, 4-ethynylphthalic anhydride;

Di-carbonate 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 modifier used is preferably 20 mol parts or less, and more preferably 10 mol parts or less, based on 100 mol parts of the total diamine component used.

Further, the polyimide precursor of the polymer (A) -polyurea copolymer or the polyimide precursor of the polymer (B) (hereinafter, also collectively referred to simply as "polyimide precursor") is closed (imidinated). This makes it possible to obtain a polyimide. The imidization rate as used herein is the ratio of the imide group to the total amount of the imide group derived from the tetracarboxylic acid dianhydride or its derivative and the carboxy group (or its derivative).

Examples of the method for imidizing the polyimide precursor 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 molecular weights of the polymers (A) and (B) used in the present invention are determined by the GPC (Gel Permeation Chromatography) method in consideration of the strength of the liquid crystal alignment film obtained from the polymer, the workability at the time of film formation, and the coating film property. The weight average molecular weight measured in 1 is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

The blending ratio of the polymer component used in the method for producing the liquid crystal alignment film of the present invention is not particularly limited, but for example, the total amount of the polymer component contained in the liquid crystal alignment agent is 0.1 to 30% by mass, preferably 0.1 to 30% by mass. It is 3 to 10% by mass. The total content of the polymers (A) and (B) contained in the liquid crystal alignment agent is preferably 1 to 9% by mass, more preferably 1.5 to 9% by mass. The total includes the case where one or two or more of the constituent unit elements are 0% by mass.

Further, in addition to the polymer (A) and the polymer (B), other polymers other than these may be mixed in the liquid crystal alignment agent used for producing the liquid crystal alignment film. At that time, the content of the other polymer is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass, based on the total amount of the polymer components. Other polymers include acrylic polymers, methacrylic polymers, polystyrene, polyamides and polysiloxanes.

The solvent contained in the liquid crystal aligning agent is not particularly limited as long as it can dissolve the polymer (A), and is, for example, a lactone solvent such as γ-valerolactone or γ-butyrolactone; γ-butyrolactam, N-Methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 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 Lactam solvents such as -cyclohexyl-2-pyrrolidone; N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethyllactoamide, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N , N-Dimethylpropanamide, etc .; 4-hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutylketone), methyl lactate, ethyl lactate, n-propyl lactate, lactic acid n-butyl, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyrrolidone, ethyl pyrrolidone, methylmethoxypropionate, ethylethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl Ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, diethyl glycol. Propropylene glycol monoethyl ether, di Propylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisopentyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethane Examples thereof include diol, 2,6-dimethyl-4-heptanol (diisobutylcarbinol), and the like. These can be used alone or in admixture of two or more.

Preferred solvent combinations include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene. Glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-ethyl-2 -Pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutylketone, N-methyl- 2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl -2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diisobutylketone, γ-butyrolactone and 4-hydroxy-4. -Methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl Ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol Monobutyl ether and diisobutylcarbinol, N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and propylene glycol Examples thereof include monobutyl ether and dipropylene glycol dimethyl ether. The type and content of such a solvent are appropriately selected according to the coating apparatus for the liquid crystal alignment agent, coating conditions, coating environment, and the like.

<Liquid crystal alignment agent>
If necessary, the liquid crystal alignment agent of the present invention may contain other components other than the above, such as a crosslinkable compound, a functional silane compound, a surfactant, and a compound having a photopolymerizable group.

The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. The crosslinkable compound is at least selected from the group consisting of a compound having an isocyanate group or a cyclocarbonate group, or a lower alkoxyalkyl group described in paragraphs [0109] to [0113] of WO2016 / 047771. In addition to the compound having one kind of group, the compound having a blocked isocyanate group and the like can be mentioned.

Blocked isocyanate compounds are available as commercial products, for example, Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B. -815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.) and the like can be preferably used.

Specific examples of the preferable crosslinkable compound include compounds represented by the following formulas (CL-1) to (CL-11).

The above is an example of a crosslinkable compound, and the present invention is not limited to these. Further, the crosslinkable compound used in the liquid crystal alignment agent of the present invention may be one kind or a combination of two or more kinds.

The content of the other crosslinkable compound in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, 0.1 to 100 parts by mass, or 1 to 50 parts by mass with respect to 100 parts by mass of the polymer component. It is a department.

The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the underlying substrate. As a specific example, the silane compound described in paragraph [0019] of International Publication 2014/119682 can be mentioned. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component.

The surfactant can be used for the purpose of improving the uniformity of the film thickness and the surface smoothness of the liquid crystal alignment film. Examples of the compound include a fluorine-based surfactant, a silicone-based surfactant, and a nonion-based surfactant. Specific examples of these include the surfactants described in paragraph [0117] of WO2016 / 047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, and more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

The compound having a photopolymerizable group is a compound having one or more polymerizable unsaturated groups such as an acrylate group and a methacrylate group in the molecule, for example, as represented by the following formulas (M-1) to (M-7). Compounds can be mentioned.

Further, the liquid crystal aligning agent of the present invention is a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge loss of the element, as described in Paragraph of International Publication No. WO2011 / 132751 (Published 2011.10.27) [ The nitrogen atom-containing heterocyclic amine compounds represented by the formulas [M1] to [M156], which are listed in 0194] to [0200], more preferably 3-picorylamine and 4-picorylamine can be added. This amine compound may be added directly to the liquid crystal alignment agent, but it is preferably added after making a solution having a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. This solvent is not particularly limited as long as it dissolves the polymer component.

The liquid crystal alignment agent of the present invention may be added with an imidization accelerator or the like for the purpose of efficiently advancing imidization by heating when firing the coating film.

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 in the range of 0.5 to 15% by mass, more preferably 1 to 10% by mass.
The range of 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 in the range of 1.5 to 4.5% by mass. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by mass, and the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by mass and the solution viscosity is in the range of 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. 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).
(1) Step of Applying Liquid Crystal Alignment Agent on 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, for example, by a roll coater method, a spin coating method, a printing method, or an inkjet. Apply by an appropriate coating method such as the 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.
(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. Then, it is preferable that a heating (post-baking) step is further carried out.
The post-bake temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake 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 the coating film is irradiated with polarized or unpolarized radiation. 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.
(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 a liquid crystal is formed between the two substrates arranged opposite to each other. To place. 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 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 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. After that, the other substrate is attached so that the liquid crystal alignment films face 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. In any case, it is desirable to remove the flow orientation at the time of filling the liquid crystal by further heating the liquid crystal composition used to a temperature at which it takes an isotropic phase and then slowly cooling it to room temperature.

(3-2) When manufacturing a PSA type liquid crystal display element The same procedure as in (3-1) above is applied except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include polymerizable compounds represented by the above formulas (M-1) to (M-7).
(3-3) When a coating film is formed on a substrate using a liquid crystal alignment agent containing a compound having a polymerizable group The same procedure as in (3-1) above is followed by a step of irradiating a liquid crystal display with ultraviolet rays, which will be described later. A method of manufacturing a display element may be adopted. 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 as 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 the polymer component. Further, the above-mentioned 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 above-mentioned photopolymerizable group at the terminal is used in the reaction. Examples thereof include the obtained polymer.

(4) Step of Irradiating Ultraviolet Light 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 (3-2) or (3-3) above. 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 lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excima laser, or 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 "H film" in which polyvinyl alcohol is stretch-oriented and iodine is absorbed is sandwiched between cellulose acetate protective films 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 cam coder, 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.

An example will be given below for explanation. The present invention is not limited to these. The abbreviations used below are as follows.

(Diisocyanate)
A-1: Trilene 2,4-diisosocyanate

(Tetracarboxylic dianhydride)
B-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride B-2: pyromellitic anhydride

(Diamine compound)
C-1: 4,4'-diaminodiphenylmethane C-2: N- (3-picoryl) -3,5-diaminobenzamide C-3: 1,3-diamino-4- {4- (4-n-heptyl) Cyclohexyl) phenoxy} benzene C-4: 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane C-5: 2,2-bis {4- (4-aminophenoxy) phenyl} propane C -1 to C-3 and C-5 are aromatic diamines, and C-4 is an aliphatic diamine.

(Organic solvent)
NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve

The measurement method performed in this example is shown below.
(Measurement of molecular weight of polymer)
The molecular weight of the polymer was measured by a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight and the weight average molecular weight were calculated as polyethylene glycol and polyethylene oxide equivalent values.
GPC device: Showa Denko GPC-101,
Column: Shodex column (KD-803, KD-805 in series)
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-phosphate) is 30 mmol / L, tetrahydrofuran (THF) ) Is 10 ml / L)
Flow rate: 1.0 ml / Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight; about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol manufactured by Polymer Laboratory. (Molecular weight; about 12,000, 4,000, 1,000)

<Synthesis example 1>
Add C-1 (1.78 g, 9.00 mmol), C-2 (1.31 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) and NMP (25 g) to a four-necked flask. Stirred to completely dissolve the diamine. Next, A-1 (1.57 g, 9.00 mmol) and NMP (8.9 g) were added and reacted at 25 ° C. for 1 hour. Then, B-1 (1.73 g, 8.82 mmol) and NMP (9.4 g) were added, and the mixture was further reacted for 16 hours to prepare a solution having a polyamic acid-polyurea copolymer (A) concentration of 15% by mass. Obtained. The polyamic acid-polyurea copolymer (A) had a number average molecular weight of 10,200 and a weight average molecular weight of 34,700.

<Comparative synthesis example 1>
A polyamic acid-polyurea solution containing a diamine other than the aromatic diamine was synthesized according to the method described in Synthesis Example 1 of paragraph [0167] of WO2014 / 126102. Add C-4 (1.53 g, 8,98 mmol), C-2 (1.31 g, 5.36 mmol), C-3 (1.37 g, 3.59 mmol) and NMP (24 g) to a four-necked flask. Stirred to completely dissolve the diamine. Next, A-1 (1.57 g, 9.00 mmol) and NMP (8.9 g) were added, and the mixture was reacted at 40 ° C. for 15 hours. Then, B-1 (1.66 g, 8.46 mmol) and NMP (9.4 g) were added, and the mixture was further reacted for 10 hours to prepare a solution having a polyamic acid-polyurea copolymer (B) concentration of 15% by mass. Got The polyamic acid-polyurea copolymer (B) had a number average molecular weight of 9,500 and a weight average molecular weight of 32,800.

<Comparative synthesis example 2>
Add C-1 (9.12 g, 46.0 mmol), C-2 (8.36 g, 34.5 mmol), C-5 (14.3 g, 34.8 mmol) and NMP (179 g) to a four-necked flask. Stirred to completely dissolve the diamine. Next, B-1 (14.8 g, 75.4 mmol) and NMP (42.7 g) were added and reacted at 25 ° C. for 1.5 hours. Then, B-2 (7.52 g, 34.5 mmol) and NMP (81.8 g) were added, and the mixture was further reacted for 17 hours to obtain a solution having a polyamic acid (C) concentration of 15% by mass. The number average molecular weight of this polyamic acid (C) was 9,600, and the weight average molecular weight was 23,000.

<Example 1>
NMP and BCS were added to the solution of the polyamic acid-polyurea copolymer (A) obtained in Synthesis Example 1 and stirred, and the polymer solid content concentration was 3% by mass, NMP was 52% by mass, and BCS was 45% by mass. The liquid crystal alignment agent (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 Examples 1 and 2>
The same method as in Example 1 was used except that the solution of the polyamic acid-polyurea copolymer (B) and the solution of the polyamic acid (C) were used instead of the solution of the polyamic acid-polyurea copolymer (A). A liquid crystal aligning agent (2) and a liquid crystal aligning agent (3) were prepared.

<Example 2>
The liquid crystal alignment agent (1) was mixed at a ratio of 30% by mass and the liquid crystal alignment agent (3) at a ratio of 70% by mass to obtain a liquid crystal alignment agent (4). 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 3>
The liquid crystal alignment agent (5) was prepared in the same manner as in Example 2 except that the liquid crystal alignment agent (2) was used instead of the liquid crystal alignment agent (1).

[Evaluation of pencil hardness]
The liquid crystal alignment agents obtained in Examples and Comparative Examples were applied to an ITO substrate having a size of 30 mm × 40 mm by a spin coating method. Then, it was dried on a hot plate at 80 ° C. for 1 minute and 30 seconds, and fired in a hot air circulation oven at 230 ° C. for 20 minutes to obtain a substrate with a liquid crystal alignment film having a film thickness of 100 nm. This substrate was measured by a pencil hardness test method (JIS K5400). The results are shown in Table 1. The larger the pencil hardness value, the higher the film hardness.

[Evaluation of surface energy]
For the substrate with a liquid crystal alignment film obtained by the same method as the evaluation of pencil hardness, the contact angle when water and diiodomethane were used was measured by a fully automatic contact angle meter (DMo-701, manufactured by Kyowa Interface Science Co., Ltd.). The surface energy of each liquid crystal alignment film was calculated using the obtained contact angle results. The results are shown in Table 2. The lower the surface energy, the higher the liquid crystal orientation.

In the table, the numerical values in parentheses in the polymer composition represent the blending ratio (parts by mass) of each polymer with respect to the total 100 parts by mass of the polymer components used for preparing the liquid crystal alignment agent.

In the table, the numerical values in parentheses in the polymer composition represent the blending ratio (parts by mass) of each polymer with respect to the total 100 parts by mass of the polymer components used for preparing the liquid crystal alignment agent.

As shown in Tables 1 and 2, the liquid crystal alignment agents of Examples 1 and 2 containing the polyamic acid-polyurea copolymer obtained with the aromatic diamine (a) and without the aliphatic diamine. Was able to obtain a liquid crystal alignment film having excellent film hardness and liquid crystal orientation as compared with the liquid crystal alignment agents of Comparative Examples 1 to 3.

The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2020-060312 filed on March 30, 2020 are cited here as the disclosure of the specification of the present invention. It is something to incorporate.

Claims (16)

1. A liquid crystal alignment agent containing the following component (A).
   Component (A): Selected from the group consisting of a polyimide precursor-polyurea copolymer having a repeating unit represented by the following formula (m1) and a repeating unit represented by the following formula (1) and an imidized polymer thereof. At least one of the polymer (A), the repeating unit represented by the formula (m1) and the repeating unit represented by the formula (1), are the following formulas (S1) to (S2). ) Is derived from the aromatic diamine (a) having any of the structures represented by), and the polymer (A) can be obtained without using an aliphatic diamine.
   

   

   (X ₁ is .Y ₁ .2 one R ₁ representing a divalent organic radical derived from an aromatic diamine represents a tetravalent organic group, each independently, a hydrogen atom or an alkyl having 1 to 5 carbon atoms .2 pieces of Z ₁ represents a group independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, alkenyl optionally having 2 to 10 carbon atoms which may have a substituent Represents an alkynyl group having 2 to 10 carbon atoms, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group which may have a group or a substituent.
   

   

   (A ₁ is a divalent organic group, A ₂ is a divalent organic group derived from an aromatic diamine, and C ₁ and C ₂ are independently hydrogen atoms or alkyl having 1 to 3 carbon atoms. It is a group.)
   

   

   (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 ). -, -NH-, -O-, -COO-, -OCO- or-((CH ₂ ) _a1- A ₁ ) _m1- . Of these, a1 is an integer of 1 to 15, and A ₁ is. , Oxygen atom or -COO-, m ₁ is an integer of 1 to 2. G ¹ and G ² are independently divalent aromatic groups having 6 to 12 carbon atoms, and 3 carbon atoms. Represents a divalent cyclic group selected from the divalent alicyclic groups of 8 to 8. Any hydrogen atom on the cyclic group may be substituted. M and n are 0 to 3 independently of each other. of an integer, m + n is .R ¹ is 1 to 6 represents an alkyl group, an alkoxyalkyl group of an alkoxy group or a C 2-20 having 1 to 20 carbon atoms having 1 to 20 carbon atoms, the ^{R 1} Any hydrogen atom to be formed may be substituted with a fluorine atom. ^{When a plurality of X 1} , X ² , G ¹ , G ² , a 1 and A ₁ are present, a plurality of X ¹ , X ² , G ^{1 are present.} , ^G 2, a1 and _{a 1} are each independently have the above definitions.)
   

   

   (X ^2a represents -CONH-, -NHCO-, -O-, -CH ₂ ^{O-, -COO- or -OCO-. R 2} represents a structure having a steroid skeleton.)
2. The liquid crystal alignment agent according to claim 1, wherein the liquid crystal alignment agent further contains the component (B).
   Component (B): A polymer (B) that is at least one selected from the group consisting of a polyimide precursor and an imidized polymer thereof, and is different from the polymer (A).
3. The liquid crystal alignment agent according to claim 1 or 2, wherein the aromatic diamine (a) is a diamine represented by the following formula (d1) or formula (d2).
   

   

   (X is a single bond, -O-, -C (CH ₃ ) _2- , -NH-, -CO-,-(CH ₂ ) _m- , -SO _2- , -O- (CH ₂ ) _{m- O -, - O-C (} CH 3) 2 -, - CO- (CH 2) m -, - NH- (CH 2) m -, - SO 2 - (CH 2) m -, - CONH- (CH _{2) m -, - CONH- (} CH 2) m -NHCO-, or -COO- _{(CH 2)} .m representing a divalent organic group m -OCO- is an integer of 1 ~ 8 .Y is , Represents the structure of any of the above formulas (S1) to (S2). In the above formula (d2), the two Ys may be the same or different from each other.)
4. Claims 1 to 3 wherein the formulas (S1) to (S2) represent any of the structures represented by the following formulas (S1-1) to (S1-7) and (S2-a). The liquid crystal alignment agent according to any one of the above.
   

   

   (In the formula, R ¹ represents 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. X ^p is − (CH ₂ ) _a −. (A is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N (CH ₃ )-, -NH-, -O-, _{-CH 2} O-, -CH _{2 OCO-,} Represents -COO- or -OCO-. A ₁ is an oxygen atom or -COO- * (however, the bond with "*" binds to (CH ₂ ) _a2 ), and A ₂ is an oxygen atom. or * -COO- (where "*" is a bond marked with _{(CH 2)} binds to _{a2) represents,} a 1, _{a 3} are each independently an integer of 0 or 1, a ₂ is an integer from 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group.)
   

   

   (In the formula, X represents formula (X1), formula (X2) or -CH ₂ O-, and Col represents formula (Col-1), formula (Col-2) or formula (Col-3). , G represents the formula (G1), the formula (G2), the formula (G3) or the formula (G4))
5. _{Any one of claims 1 to 4, wherein Y 1 of the} formula (m1) _{and A 2} of the formula (1) represent a divalent organic group derived from the aromatic diamine (a). The liquid crystal alignment agent according to the section.
6. In the formula (1), A ₁ is a divalent aromatic group having 6 to 30 carbon atoms having at least one benzene ring, or a divalent acyclic aliphatic group or alicyclic group having 4 to 30 carbon atoms. The liquid crystal aligning agent according to any one of claims 1 to 5, which is a formula group.
7. The liquid crystal alignment agent according to any one of claims 1 to 6, wherein the polymer (A) is obtained by using a compound containing two isocyanate groups in the molecule.
8. Claims 2 to 7 wherein the polymer (B) is at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit represented by the following formula (m2) and an imidized polymer thereof. The liquid crystal alignment agent according to any one of the above.
   

   

   (X ₂ represents a tetravalent organic group. Y ₂ represents a divalent organic group. R ₂ and Z _{2 are synonymous with R 1} and Z ₁ of the formula (m1), respectively, and two. R ₂ and Z ₂ may be the same or different from each other.)
9. The liquid crystal alignment agent according to any one of claims 2 to 8, wherein the polymer (B) does not have a repeating unit represented by the formula (1).
10. Claims 1 to 1 to claim, wherein at least one of the polymers (A) and (B) is obtained by using a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof. 9. The liquid crystal aligning agent according to any one of 9.
    

    

    (X represents a structure selected from the group consisting of the following (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. Yes, A ₁ and A ₂ independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide group. * 1 is attached to one acid anhydride group. * 2 is a bond that binds to the other acid anhydride group. In the above formula (x-13), the two A _2s may be the same or different from each other. .)
11. The polymer (A) has at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding the imide ring of polyimide), a secondary amino group and a tertiary amino group. The liquid crystal aligning agent according to any one of claims 1 to 10, which is obtained by using an aromatic diamine having the above.
12. The polymer (B) has at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle (excluding the imide ring of polyimide), a secondary amino group and a tertiary amino group. The liquid crystal aligning agent according to any one of claims 2 to 11, which is obtained by using a diamine having the above.
13. Any of claims 2 to 12, wherein the content ratio of the component (A) and the component (B) is 10/90 to 90/10 in terms of the mass ratio of [component (A)] / [component (B)]. The liquid crystal alignment agent according to item 1.
14. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to any one of claims 1 to 13.
15. A liquid crystal display element including the liquid crystal alignment film according to claim 14.
16. The liquid crystal aligning agent according to any one of claims 1 to 13 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 by arranging the liquid crystal cells facing 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.