CN114174468A

CN114174468A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN114174468A
Application number: CN202080055417.1A
Authority: CN
Inventors: 森内正人; 长谷川直史
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2019-09-19
Filing date: 2020-09-16
Publication date: 2022-03-11
Also published as: WO2021054365A1; KR20220065753A; TW202124682A; JPWO2021054365A1

Abstract

The invention aims to provide a liquid crystal aligning agent which can manufacture a liquid crystal aligning film with required performance including close adhesion and good reworkability, and a liquid crystal aligning film and a liquid crystal display element manufactured by the liquid crystal aligning agent. A liquid crystal aligning agent comprising a polymer obtained from a diamine component comprising: formula [ I]At least one 1 st diamine represented by the formula DA-1; having a formula selected from [ S1]]～[S3]At least one of the side chain structures in the group shown is a2 nd diamine represented by the formula SC-1.

Description

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

Technical Field

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

Background

Liquid crystal devices have been widely used as display units of personal computers, smart phones, cellular phones, televisions, and the like. The liquid crystal device includes, for example: a liquid crystal layer sandwiched between the element substrate and the color filter substrate; a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer; an alignment film for controlling the alignment of liquid crystal molecules in the liquid crystal layer; and a Thin Film Transistor (TFT) for converting (switching) an electric signal supplied to the pixel electrode. As a driving method of liquid crystal molecules, there are known: a Vertical electric field system such as a TN (twisted nematic) system and a VA (Vertical Alignment) system; and a lateral electric field system such as an IPS (In-Plane Switching) system and a Fringe Field Switching (FFS) system.

A lateral electric field system in which electrodes are usually formed only on one side of a substrate and an electric field is applied in a direction parallel to the substrate is known as a liquid crystal display element which has a wider viewing angle characteristic and can display high quality, compared to a conventional vertical electric field system in which a liquid crystal is driven by applying a voltage to electrodes formed on upper and lower substrates. As a method for aligning liquid crystals in a certain direction, there is a method of performing so-called rubbing treatment in which a polymer film such as polyimide is formed on a substrate and the surface is rubbed with cloth, and this method is also widely used industrially.

A liquid crystal alignment film, which is a constituent member of a liquid crystal display element, is a film for uniformly aligning liquid crystals, but it requires not only alignment uniformity of liquid crystals but also various characteristics. For example, there are problems as follows: electric charges are accumulated in the liquid crystal alignment film by a voltage for driving the liquid crystal, and the accumulated electric charges disturb the alignment of the liquid crystal or affect display as an afterimage or afterimage (hereinafter, an afterimage derived from the remnant DC) to significantly lower the display quality level of the liquid crystal display element, and thus a liquid crystal aligning agent has been proposed to overcome these problems (see patent document 2).

In addition, since the economy in the production process is very important, it is also necessary that the element substrate be easily recycled. Namely, it is required that: when a defect occurs in the liquid crystal alignment film after the liquid crystal alignment film is formed from the liquid crystal alignment agent and then the alignment property or the like is inspected, the liquid crystal alignment film can be removed from the substrate, and a rework (rework) step of recovering the substrate can be easily performed.

However, since the liquid crystal alignment film is required to have adhesion to the substrate, a liquid crystal alignment agent is required which can produce a liquid crystal alignment film having the required adhesion and which can easily perform a rework process.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. H2013-167782

Patent document 2: international publication No. 02/33481 pamphlet

Disclosure of Invention

Problems to be solved by the invention

In view of the above circumstances, an object of the present invention is to provide a liquid crystal aligning agent capable of producing a liquid crystal alignment film having a desired performance including adhesiveness and excellent reworkability, and a liquid crystal alignment film and a liquid crystal display element produced from the liquid crystal aligning agent.

Means for solving the problems

As a result of intensive studies, the present inventors have found that a diamine having a specific side chain structure is introduced as a diamine component together with a specific diamine having an imide skeleton, and that good residual characteristics and high reliability can be ensured, thereby completing the present invention.

The liquid crystal aligning agent of the present invention for achieving the above object comprises a polymer obtained from a diamine component comprising: at least one 1 st diamine represented by the following formula [ I ]; at least one 2 nd diamine having a side chain structure selected from the group consisting of the following formulas [ S1] to [ S3 ].

(in the formula [ I ]]In, Z¹Selected from the following formula [ Z-1]～[Z－9]. Denotes a bond. )

(formula [ S1]]In, X¹And X²Each independently represents a single bond, - (CH)₂)_a- (a represents an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃) -, -NH-, -O-, -COO-, -OCO-or- ((CH)₂)_a1－A₁)_m1- (a1 is an integer of 1 to 15, A)₁Represents an oxygen atom or-COO-, m₁Is an integer of 1 to 2. At m₁In the case of 2, a plurality of a1 and A₁Each independently having the above definition). G¹And G²Each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group is optionally substituted by at least one selected from the group consisting of 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, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, and a fluorine atom. m and n are each independently an integer of 0 to 3, and the sum of m and n is 1 to 6, preferably 1 to 4. R¹Represents 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 to form R¹Optionally substituted with fluorine atoms. )

-X³-R² [S2]

(formula [ S2]]In, X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O-, -COO-or-OCO-. R²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine atoms. )

-X⁴-R³ [S3]

(formula [ S3]]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-. R³Represents a structure having a steroid skeleton. )

Effects of the invention

According to the present invention, a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display device can be provided, in which the relaxation of accumulated charges of the liquid crystal aligning agent is fast, the reliability is improved, and particularly the reliability after high-temperature, high-humidity aging is improved.

Detailed Description

The present invention will be described in detail below.

The liquid crystal aligning agent of the present invention comprises a polymer obtained from a diamine component comprising a1 st diamine having a structure represented by the above formula [ I ] and a2 nd diamine compound having a side chain structure represented by the above formulae [ S1] to [ S3], and an organic solvent, and the diamine is first described.

< 1 st diamine >

The 1 st diamine has a structure represented by the following formula [ I ].

(in the formula [ I ]]In, Z¹As shown in the above formula [ I]The definition of (1). )

In the formula [ I]In (A), the position of the amino group is preferably as shown in the following formula [ I-1]Or [ I-2]Such para or meta. In addition, Z¹Selected from the following formula [ Z-1]～[Z－9]. Denotes a bond.

The 1 st diamine of the present invention can be obtained by reducing a dinitro compound to convert a nitro group into an amino group. The method for reducing the dinitro compound is not particularly limited, and the following methods are exemplified: palladium-carbon, platinum oxide, raney nickel, platinum black, rhodium-alumina, platinum sulfide carbon, and the like are used as a catalyst, and reduction is performed by hydrogen gas, hydrazine, hydrogen chloride, and the like in a solvent such as ethyl acetate, toluene, tetrahydrofuran, dioxane, alcohol, and the like. If necessary, the reaction may be carried out under pressure using an autoclave or the like.

The thus obtained 1 st diamine compound of the present invention can be used as a raw material for polyimide precursors such as polyamic acids and polyamic acid esters, polyimides, polyureas, and polyamides (these are collectively referred to as "polymers"). The polymer can be used as a liquid crystal aligning agent by dissolving in a predetermined organic solvent, for example, and its use is not limited.

Among the above-mentioned 1 st diamines, a diamine represented by the following formula [ II ] is a novel compound.

(in the formula [ II ]]In, Z²Selected from the following formula [ Z-1]～[Z－4]、[Z－6]And [ Z-7]. Denotes a bond. )

In the formula [ II]In the above formula, the position of the amino group is preferably represented by the formula [ I-1]Or [ I-2]Such para or meta. In this case, the above formula [ I-1]Or [ I-2]In, Z¹Preferably selected from the above-mentioned formula [ Z-1]～[Z－4]、[Z－6]And [ Z-7]。

< 2 nd diamine having a specific side chain structure >

The 2 nd diamine having a specific side chain structure is a substance exhibiting vertical orientation, and has at least one side chain structure selected from the group represented by the following formulas [ S1] to [ S3 ]. Next, diamines having specific side chain structures represented by the formulae [ S1] to [ S3] as examples of the 2 nd diamine having the specific side chain structure will be described in order.

[A] The method comprises the following steps A diamine having a specific side chain structure represented by the following formula [ S1 ].

The above formula [ S1]In, X¹And X²Each independently represents a single bond, - (CH)₂)_a- (a represents an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃) -, -NH-, -O-, -COO-, -OCO-or- ((CH)₂)_a1－A₁)_m1- (a1 is an integer of 1 to 15, A)₁Represents an oxygen atom or-COO-, m₁Is an integer of 1 to 2. At m₁In the case of 2, a plurality of a1 and A₁Each independently having the definition).

Among them, X is X in view of availability of raw materials and ease of synthesis¹And X²Are each independently preferably a single bond, - (CH)₂)_a- (a represents an integer of 1 to 15), -O-, -CH₂O-or-COO-, more preferably a single bond, - (CH)₂)_a- (a represents an integer of 1 to 10), -O-, -CH₂O-or-COO-.

Further, the above formula [ S1]In (G)¹And G²Each independently represents a divalent cyclic group selected from the group consisting of a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group is optionally substituted by 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, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom. m and n independently represent an integer of 0 to 3, and the sum of m and n is 1 to 6, preferably 1 to 4.

Further, the above formula [ S1]In, R¹Represents 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. Form R¹Optionally hydrogen atom ofOptionally substituted with fluorine atoms. Examples of the divalent aromatic group having 6 to 12 carbon atoms include phenylene, biphenylene, naphthylene, and the like. Examples of the divalent alicyclic group having 3 to 8 carbon atoms include cyclopropylene and cyclohexylene.

Therefore, preferable specific examples of the formula [ S1] include the following formulae [ S1-x 1] to [ S1-x 7 ].

The above formula [ S1-x 1]～[S1－x7]In, R¹And the above formula [ S1]The same applies. X^pIs represented by- (CH)₂)_a- (a represents an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O－、－CH₂OCO-, -COO-or-OCO-. A. the₁Represents an oxygen atom or a bond of-COO-and (CH)₂)_a2Bonding). A. the₂Represents an oxygen atom or a bond of-COO- (with "+") and (CH)₂)_a2Bonding). a is₃Represents an integer of 0 or 1, a₁And a₂Each independently represents an integer of 2 to 10. Cy represents a1, 4-cyclohexylene group or a1, 4-phenylene group.

[B] The method comprises the following steps A diamine having a specific side chain structure represented by the following formula [ S2 ].

-X³-R² [S2]

The above formula [ S2]In, X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O-, -COO-or-OCO-. Among them, X is X in terms of the liquid crystal aligning property of the liquid crystal aligning agent³preferably-CONH-, -NHCO-, -O-, -CH₂O-, -COO-or-OCO-.

Further, the above formula [ S2]In, R²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms. Form R²Optionally substituted with fluorine atoms. Among them, R is R in terms of the liquid crystal alignment property of the liquid crystal aligning agent²Preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms.

As formula [ S2]Preferred specific example of (1), X³is-O-, -CH₂Any of O-, -COO-or-OCO-, preferably R²When the alkyl group has 3 to 20 carbon atoms or the alkoxyalkyl group has 2 to 20 carbon atoms, R is more preferably²In the case of an alkyl group having 3 to 20 carbon atoms, R is formed²Optionally substituted with fluorine atoms.

[C] The method comprises the following steps A diamine having a specific side chain structure represented by the following formula [ S3 ].

-X⁴-R³ [S3]

The above formula [ S3]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-. R³Represents a structure having a steroid skeleton. Examples of the steroid skeleton include a skeleton represented by the following formula (st) in which three six-membered rings and one five-membered ring are bonded.

Examples of the formula [ S3] include the following formula [ S3-x ]. Me represents a methyl group.

In the formula [ S3-X ], X represents the formula [ X1] or [ X2 ]. Further, Col represents any one group selected from the group consisting of the formulas [ Col1] to [ Col3], and G represents any one group selected from the group consisting of the formulas [ G1] to [ G4 ]. Denotes the site of bonding to other groups.

Examples of preferred combinations of X, Col and G in the above formula [ S3-x ] include the following combinations. Namely: [ X1], [ Col1] and [ G1 ]; [ X1], [ Col1] and [ G2 ]; [ X1], [ Col2] and [ G1 ]; [ X1], [ Col2] and [ G2 ]; [ X1], [ Col3] and [ G2 ]; [ X1], [ Col3] and [ G1 ]; [ X2], [ Col1] and [ G2 ]; [ X2], [ Col2] and [ G2 ]; [ X2], [ Col2] and [ G1 ]; [ X2], [ Col3] and [ G2 ]; [ X2], [ Col1] and [ G1 ].

Specific examples of the formula [ S3] include: a structure in which a hydroxyl group (hydroxyl group) is removed from a steroid compound described in paragraph [0024] of Japanese patent laid-open No. 4-281427, a structure in which an acid chloride group is removed from a steroid compound described in paragraph [0030] of the publication, a structure in which an amino group is removed from a steroid compound described in paragraph [0038] of the publication, a structure in which a halogen atom is removed from a steroid compound described in paragraph [0042] of the publication, and structures described in paragraphs [0018] to [0022] of Japanese patent laid-open No. 8-146421, and the like.

As a representative example of the steroid skeleton, cholesterol (a combination of [ Col1] and [ G2] in the formula [ S3-x ] is given), but a steroid skeleton not containing the cholesterol may be used. That is, examples of the diamine having a steroid skeleton include 3, 5-diaminobenzoic acid cholesteryl ester and the like, but a diamine component containing no diamine having the aforementioned cholesterol skeleton may be used. As the diamine having a specific side chain structure, a diamine having no amide bond at the position where the diamine is linked to the side chain can be used. In the present embodiment, even when a diamine component containing no diamine having a cholesterol skeleton is used, a liquid crystal alignment agent capable of providing a liquid crystal alignment film and a liquid crystal display device capable of securing a high voltage holding ratio for a long period of time can be provided.

The diamine having a side chain structure represented by the above formulas [ S1] to [ S3] is preferably at least one selected from the group consisting of diamines represented by the following formulas [1] and [2 ].

(formula [1]]Wherein Y represents a group selected from the above-mentioned formulas [ S1]]～[S3]Monovalent groups in the side chain structures shown. In the formula [2]Wherein X represents a single bond, -O-,－C(CH₃)₂－、－NH－、－CO－、－(CH₂)_m－、－SO₂－、－O－(CH₂)_m－O－、－O－C(CH₃)₂－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－SO₂－(CH₂)_m－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m－NHCO－、－COO－(CH₂)_m－OCO－、－CONH－、－NH－(CH₂)_m-NH-, or-SO₂－(CH₂)_m－SO₂-. m is an integer of 1 to 8. Two Y' S are independently selected from the group consisting of the formula [ S1]]～[S3]Monovalent groups in the side chain structures shown. )

Preferable specific examples of the diamine represented by the above formula [1] include diamines represented by the following formulae [ 1-S1 ] to [ 1-S3 ]. Specific examples of the diamine represented by the formula [2] are described below with respect to diamines having a specific side chain structure of a two-side chain type exhibiting vertical alignment.

The above formula [ 1-S1]In, X¹、X²、G¹、G²、R¹M and n are the same as the above formula [ S1]]The same is true in (1). The above formula [ 1-S2]In, X³And R²And the above formula [ S2]The same is true in (1). The above formula [ 1-S3]In, X⁴And R³And the above formula [ S3]The same is true in (1).

(diamine having a specific side chain structure of a two-side chain type exhibiting vertical alignment)

The diamine having a specific side chain structure of a two-side chain type exhibiting vertical alignment is represented by the above formula [2 ].

The above formula [2]In the above formula, X preferably represents a single bond, -O-, -NH-, or-O- (CH)₂)_m－O－。

In the formula [2], Y may be meta-position or ortho-position to the position of X, but is preferably ortho-position. That is, the formula [2] is preferably the following formula [ 1' ].

Further, the above formula [2]]Middle, two amino (-NH)₂) The position (C) may be any position on the benzene ring, but is preferably represented by the following formula [1]]－a1～[1]The position represented by-a 3, more preferably the following formula [1]-a 1. In the following formula, X is the same as the above formula [2]]The same is true in (1). The following formula [1]]－a1～[1]-a 3 indicates the position of the two amino groups, omitting the above formula [2]]The expression of Y shown in (a) is omitted.

Therefore, based on the above formulas [ 1' ] and [1] -a 1 to [1] -a 3, the above formula [2] is preferably any structure selected from the group consisting of the following formulas [1] -a 1-1 to [1] -a 3-2, and more preferably a structure represented by the following formula [1] -a 1-1. In the following formulae, X and Y are the same as in the above formula [2 ].

Examples of the above-mentioned formulas [ S1] to [ S3] include the following formulas [ S ] -1 to [ S ] -20. Among them, preferred examples of the formula [ S1] are the following formulae [ S ] -1 to [ S ] -4, [ S ] -8 or [ S ] -10. In the following formulae, the bonding position to the phenyl group in the formulae [1], [ 1' ] and [1] -a 1 to [1] -a 3 is represented. In addition, in [ S ] -1 to [ S ] -20, n is an integer of 1 to 20, and m is an integer of 1 to 6.

The diamine component contains a diamine having a double-side chain with a predetermined structure, and thus a liquid crystal alignment film in which the ability to vertically align liquid crystals is not easily reduced even when the film is heated excessively is obtained. Further, the diamine component containing the diamine having two side chains also serves as a liquid crystal alignment film in which the ability to vertically align liquid crystals is not easily lowered even when the film is damaged by contact with a foreign substance. That is, the diamine component contains the diamine having both side chains, and thus a liquid crystal aligning agent capable of providing a liquid crystal alignment film having various excellent characteristics can be provided.

In the present embodiment, when the 1 st diamine and the 2 nd diamine are contained in the diamine component, the content ratio of the 1 st diamine is preferably 10 to 90 mol%, more preferably 20 to 80 mol% of the total diamine component. The content of the 2 nd diamine is preferably 10 to 90 mol%, more preferably 20 to 80 mol%. When other diamines described later are contained, the total content of the 1 st diamine and the 2 nd diamine is preferably 95 mol% or less, and more preferably 90 mol% or less.

< other diamines: diamine having photoreactive side chain

The diamine component of the present embodiment may contain a diamine having a photoreactive side chain as another diamine. The diamine component contains a diamine having a photoreactive side chain, and thus the photoreactive side chain can be introduced into a specific polymer or other polymers.

Specific examples of the diamine having a photoreactive side chain include, but are not limited to, diamines described in paragraphs [0124] to [0132] of Japanese unexamined patent publication No. 2016-140328. More preferable specific examples include the following formulas (a-1) to (a-4).

(X⁹、X¹⁰Each independently represents a bonding group as a single bond, -O-, -COO-, -NHCO-, or-NH-, and Y represents a group optionally substituted with a fluorine atomAn alkylene group having 1 to 20 carbon atoms. )

These diamines having a photoreactive side chain may be used singly or in combination of two or more. The liquid crystal alignment film may be used singly or in combination of two or more, depending on the properties such as liquid crystal alignment property, pretilt angle, voltage holding property, and accumulated charge when the liquid crystal alignment film is formed, and the response speed of the liquid crystal when the liquid crystal display element is formed.

In the present embodiment, when the diamine component contains a photoreactive side chain diamine, the photoreactive side chain diamine is preferably 10 to 70 mol%, more preferably 10 to 60 mol% of the total diamine component.

< other diamines: diamines other than the above

The other diamine optionally contained in the diamine component for obtaining the specific polymer is not limited to the diamine having a photoreactive side chain and the like.

In the case of producing a polyimide precursor and/or a polyimide, a diamine other than the above-mentioned diamines may be used in combination as the diamine component within a range not to impair the effects of the present invention. Specifically, examples thereof include: the diamine described in paragraph [0135] of Japanese unexamined patent publication No. WO 2016-140328, or a diamine represented by any of the following formulas (z-1) to (z-18), a diamine having a radical-initiating function such as the following formulas (R1) to (R5), or a diamine having a group "-N (D) -" (D represents a protective group which is released by heating and substituted with a hydrogen atom, preferably a t-butoxycarbonyl group) such as the following formulas (5-1) to (5-11).

(wherein n is an integer of 2 to 10.)

Specific examples of diamines which are preferred among the diamines described in paragraph [0135] of the above-mentioned Japanese unexamined patent publication WO 2016-140328 are shown below.

P-phenylenediamine, 2, 3, 5, 6-tetramethylp-phenylenediamine, 2, 5-dimethylphenylenediamine, m-phenylenediamine, 2, 4-dimethylm-phenylenediamine, 2, 5-diaminotoluene, 2, 6-diaminotoluene, 4 ' -diaminobiphenyl, 3 ' -dimethyl-4, 4 ' -diaminobiphenyl, 3 ' -dimethoxy-4, 4 ' -diaminobiphenyl, 3 ' -dihydroxy-4, 4 ' -diaminobiphenyl, 3 ' -dicarboxyl-4, 4 ' -diaminobiphenyl, 3 ' -difluoro-4, 4 ' -biphenyl, 3 ' -trifluoromethyl-4, 4 ' -diaminobiphenyl, 3 ' -diaminobiphenyl, 2, 3 ' -diaminobiphenyl, 4 ' -diaminodiphenylmethane, 3 ' -diaminodiphenylmethane, 2, 4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenylmethane, etc, 3, 4 ' -diaminodiphenylmethane, 2, 3 ' -diaminodiphenylmethane, 4 ' -diaminodiphenyl ether, 3 ' -diaminodiphenyl ether, 3, 4 ' -diaminodiphenyl ether, 2, 3 ' -diaminodiphenyl ether, 4 ' -sulfonyldiphenylamine, 3 ' -sulfonyldiphenylamine, bis (4-aminophenyl) silane, bis (3-aminophenyl) silane, dimethyl-bis (4-aminophenyl) silane, dimethyl-bis (3-aminophenyl) silane, 4 ' -thiodiphenylamine, 3 ' -thiodiphenylamine, 4 ' -diaminodiphenylamine, 3 ' -diaminodiphenylamine, 3, 4 ' -diaminodiphenylamine, 2, 3 ' -diaminodiphenylamine, N-methyl (4, 4 ' -diaminodiphenyl) amine, N-methyl (3, 3 '-diaminodiphenyl) amine, N-methyl (3, 4' -diaminodiphenyl) amine, N-methyl (2, 2 '-diaminodiphenyl) amine, N-methyl (2, 3' -diaminodiphenyl) amine, 4 '-diaminobenzophenone, 3' -diaminobenzophenone, 3, 4 '-diaminobenzophenone, 1, 4-diaminonaphthalene, 2, 3' -diaminobenzophenone, 1, 5-diaminonaphthalene, 1, 2-bis (4-aminophenyl) ethane, 1, 2-bis (3-aminophenyl) ethane, 1, 3-bis (4-aminophenyl) propane, 1, 3-bis (3-aminophenyl) propane, 1, 4-bis (4-aminophenyl) butane, 1, 4-bis (3-aminophenyl) butane, bis (3, 5-diethyl-4-aminophenyl) methane, 1, 3-bis (4-aminophenoxy) propane, 1, 3-bis (3-aminophenoxy) propane, 1, 4-bis (4-aminophenoxy) butane, 1, 4-bis (3-aminophenoxy) butane, 1, 5-bis (4-aminophenoxy) pentane, 1, 5-bis (3-aminophenoxy) pentane, 1, 6-bis (4-aminophenoxy) hexane, 1, 6-bis (3-aminophenoxy) hexane, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 1, 4-bis (4-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 4-bis (4-aminobenzyl) benzene, 1, 3-bis (4-aminophenoxy) benzene, 4 '- [1, 4-phenylenebismethylene ] diphenylamine, 4' - [1, 3-phenylenebismethylene ] diphenylamine, 3, 4 '- [1, 4-phenylenebismethylene ] diphenylamine, 3, 4' - [1, 3-phenylenebismethylene ] diphenylamine, 3 '- [1, 4-phenylenebismethylene ] diphenylamine, 3' - [1, 3-phenylenebismethylene ] diphenylamine, 1, 4-phenylenebis [ (4-aminophenyl) methanone ], 1, 4-phenylenebis [ (3-aminophenyl) methanone ], 1, 3-phenylenebis [ (4-aminophenyl) methanone ], 1, 3-phenylenebis [ (3-aminophenyl) methanone ], 1, 4-phenylenebis (4-aminobenzoate), 1, 4-phenylenebis (3-aminobenzoate), 1, 3-phenylenebis (4-aminobenzoate), 1, 3-phenylenebis (3-aminobenzoate), bis (4-aminophenyl) terephthalate, bis (3-aminobenzoate), Bis (3-aminophenyl) terephthalate, bis (4-aminophenyl) isophthalate, bis (3-aminophenyl) isophthalate, N '- (1, 4-phenylene) bis (4-aminobenzamide), N' - (1, 3-phenylene) bis (4-aminobenzamide), N '- (1, 4-phenylene) bis (3-aminobenzamide), N' - (1, 3-phenylene) bis (3-aminobenzamide), N '-bis (4-aminophenyl) terephthalamide, N' -bis (3-aminophenyl) terephthalamide, N '-bis (4-aminophenyl) isophthalamide, N' -bis (3-aminophenyl) isophthalamide, 9, 10-bis (4-aminophenyl) anthracene, 4 '-bis (4-aminophenoxy) diphenylsulfone, bis (3-aminophenyl) isophthalamide, N' -bis (4-aminophenyl) isophthalamide, N '-bis (3-aminophenyl) isophthalamide, 9, 10-bis (4-aminophenyl) anthracene, 4' -bis (4-aminophenoxy) diphenylsulfone, 2, 2 ' -bis [ 4- (4-aminophenoxy) phenyl ] propane, 2 ' -bis [ 4- (4-aminophenoxy) phenyl ] hexafluoropropane, 2 ' -bis (4-aminophenyl) hexafluoropropane, 2 ' -bis (3-amino-4-methylphenyl) hexafluoropropane, 2 ' -bis (4-aminophenyl) propane, 2 ' -bis (3-amino-4-methylphenyl) propane, 3, 5-diaminobenzoic acid, aromatic diamines such as 2, 5-diaminobenzoic acid, bis (4-aminocyclohexyl) methane, alicyclic diamines such as bis (4-amino-3-methylcyclohexyl) methane, 1, 3-diaminopropane, 1, 4-diaminobutane, 1, 5-diaminopentane, 1, 4-diaminopentane, 2 ' -bis (4-aminophenoxy) phenyl ] hexafluoropropane, 2 ' -bis (4-aminophenyl) propane, 2 ' -bis (3-aminophenyl) propane, 2 ' -bis (3-methylcyclohexyl) methane, 2 ' -bis (3-diaminobutane, etc.), Aliphatic diamines such as 1, 6-diaminohexane.

The other diamines may be used singly or in combination of two or more depending on the properties such as liquid crystal alignment properties, pretilt angle, voltage holding properties, and accumulated charge when a liquid crystal alignment film is formed.

< Polymer >

The polymer of the present invention is a polymer obtained by using the diamine, but preferably includes polyamic acid, polyamic acid ester, polyimide, polyurea, polyamide, and the like obtained by reacting a diamine component with tetracarboxylic dianhydride. From the viewpoint of use as a liquid crystal aligning agent, at least one selected from the group consisting of the above-mentioned polyimide precursors such as polyamic acids and polyamic acid esters, and polyimides which are imide compounds of the polyimide precursors is preferable.

< tetracarboxylic dianhydride >

As the tetracarboxylic acid component for obtaining the specific polymer, a tetracarboxylic dianhydride represented by the following formula [ II' ] or a derivative thereof (tetracarboxylic acid, dihalotetracarboxylic acid compound, tetracarboxylic acid dialkyl ester, or dihalotetracarboxylic acid dialkyl ester) (these are collectively referred to as specific tetracarboxylic acids) can be used.

(in the formula [ II ' ], Q represents at least one structure selected from the group consisting of the following formulas [ II ' -a ] to [ II ' -Q ]

Formula [ II' -a]In, Q¹～Q⁴Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a benzene ring. Formula [ II' -g]In, Q⁵And Q⁶Each independently represents a hydrogen atom or a methyl group.

Among Q in the formula [ II ' ], tetracarboxylic dianhydrides having a structure represented by the formula [ II ' -a ], the formula [ II ' -c ] to the formula [ II ' -g ], the formula [ II ' -k ] to the formula [ II ' -m ] or the formula [ II ' -p ], and tetracarboxylic acid derivatives thereof are preferable from the viewpoints of ease of synthesis and ease of polymerization reactivity in the production of a polymer. More preferably, the structure represented by the formula [ II '-a ], the formula [ II' -e ] to the formula [ II '-g ], the formula [ II' -l ], the formula [ II '-m ] or the formula [ II' -p ]. Particularly preferred are tetracarboxylic dianhydrides having a structure represented by [ II '-a ], formula [ II' -e ], formula [ II '-f ], formula [ II' -l ], formula [ II '-m ] or formula [ II' -p ], and tetracarboxylic acid derivatives thereof.

More specifically, the following formula [ II '-a-1 ] or formula [ II' -a-2 ] is preferably used.

The specific tetracarboxylic acid is preferably 50 to 100 mol% based on 100 mol% of the total tetracarboxylic acid component. Among them, more preferably 70 to 100 mol%. Particularly preferably 80 to 100 mol%.

The specific tetracarboxylic acid may be used alone or in combination of two or more depending on the solubility in a solvent of the specific polymer, the coatability of a liquid crystal aligning agent, the liquid crystal alignment properties when a liquid crystal alignment film is formed, the voltage holding ratio, the accumulated charge, and other properties.

As the tetracarboxylic acid component for obtaining the specific polymer, a tetracarboxylic acid (hereinafter, also referred to as other tetracarboxylic acid) or a derivative thereof other than the specific tetracarboxylic acid may be contained. Examples of the other tetracarboxylic acid include a tetracarboxylic acid compound shown below, or a derivative thereof (a tetracarboxylic dianhydride, a dihalotetracarboxylic acid compound, a tetracarboxylic acid dialkyl ester compound, or a dihalotetracarboxylic acid dialkyl ester compound).

That is, as other tetracarboxylic acids, there can be mentioned: 1, 2, 5, 6-naphthalenetetracarboxylic acid, 1, 2, 5, 6-anthracenetetracarboxylic acid, 2, 3, 3 ', 4-biphenyltetracarboxylic acid, bis (3, 4-dicarboxyphenyl) ether, 3, 3 ', 4, 4 ' -benzophenonetetracarboxylic acid, bis (3, 4-dicarboxyphenyl) sulfone, bis (3, 4-dicarboxyphenyl) methane, 2-bis (3, 4-dicarboxyphenyl) propane, 1, 1, 1, 3, 3, 3-hexafluoro-2, 2-bis (3, 4-dicarboxyphenyl) propane, bis (3, 4-dicarboxyphenyl) dimethylsilane, bis (3, 4-dicarboxyphenyl) diphenylsilane, 2, 3, 4, 5-pyridinetetracarboxylic acid, 2, 6-bis (3, 4-dicarboxyphenyl) pyridine, 3, 3 ', 4, 4' -diphenylsulfonetetracarboxylic acid, 3, 4, 9, 10-perylene-tetracarboxylic acid, and the like.

Other tetracarboxylic acids may be used alone or in combination of two or more depending on the solubility in a solvent of a specific polymer, the coating property of a liquid crystal aligning agent, the liquid crystal aligning property in the case of forming a liquid crystal alignment film, the voltage holding ratio, the accumulated charge, and other properties.

The polyimide precursor used in the present invention includes polyamic acids and polyamic acid esters. In the polyamic acid ester, all the constituent units may have an amic acid ester structure, or a part of the constituent units may have an amic acid structure.

< method for producing Polymer >

The polymer of the present invention is obtained by a method of reacting the diamine component (diamine component containing a plurality of kinds of the 1 st diamine and the 2 nd diamine) described above with a tetracarboxylic acid component. Examples of the method include the following methods: the polyamic acid is obtained by reacting a diamine component containing one or more diamines with at least one tetracarboxylic acid component selected from the group consisting of tetracarboxylic acid dianhydrides and derivatives of tetracarboxylic acids thereof. Specifically, the following method is used: the polyamic acid is obtained by polycondensation of a primary diamine or a secondary diamine and a tetracarboxylic dianhydride.

To obtain the polyamic acid ester, it is possible to use: a method of polycondensing a tetracarboxylic acid dialkyl ester obtained by esterifying a carboxylic acid group with a primary diamine or a secondary diamine, a method of polycondensing a dihalotetracarboxylic acid compound obtained by halogenating a carboxylic acid group with a primary diamine or a secondary diamine, or a method of converting a carboxyl group of a polyamic acid into an ester. In order to obtain polyimide, a method of ring-closing the polyamic acid or polyamic acid ester described above to obtain polyimide can be used.

The reaction of the diamine component with the tetracarboxylic acid component is usually carried out in a solvent. The solvent used in this case is not particularly limited as long as it dissolves the polyimide precursor formed. Examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ -butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and 1, 3-dimethyl-2-imidazolidinone. When the polyimide precursor has high solubility in a solvent, a solvent represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formulas [ D-1 ] to [ D-3 ], or the like can be used.

Formula [ D-1]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms. Formula [ D-2]In (D)²Represents an alkyl group having 1 to 3 carbon atoms. Formula [ D-3]In (D)³Represents an alkyl group having 1 to 4 carbon atoms.

These solvents may be used singly or in combination of two or more. The solvent that does not dissolve the polyimide precursor may be mixed with the above-mentioned solvent and used as long as the polyimide precursor produced does not precipitate. Further, since moisture in the solvent inhibits the polymerization reaction and causes hydrolysis of the polyimide precursor to be produced, it is preferable to use a dehydrated and dried solvent as the solvent.

When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the following methods may be mentioned: a method of stirring a solution in which a diamine component is dispersed or dissolved in a solvent, and adding a tetracarboxylic acid component as it is or in a solvent; conversely, a method of adding a diamine component to a solution in which a tetracarboxylic acid component is dispersed or dissolved in a solvent; a method of alternately adding the diamine component and the tetracarboxylic acid component, and any of the methods can be used. In addition, in the case of using a plurality of diamine components or tetracarboxylic acid components to react, they may be reacted in a state of being mixed in advance, or they may be reacted separately and sequentially, or low molecular weight materials obtained by separately reacting may be mixed and reacted to produce a polymer.

The temperature for polycondensation of the diamine component and the tetracarboxylic acid component may be selected from any temperature within the range of-20 to 150 ℃, but is preferably within the range of-5 to 100 ℃. The reaction can be carried out at any concentration, but the concentration of the diamine component and the tetracarboxylic acid component is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, relative to the solvent. The reaction may be carried out at a high concentration at the initial stage of the reaction, and then a solvent may be added.

In the polymerization reaction of the polyimide precursor, the ratio of the total mole number of the diamine component to the tetracarboxylic acid component (total mole number of the diamine component/total mole number of the tetracarboxylic acid component) is preferably 0.8 to 1.2. As in the case of the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polyimide precursor to be produced.

The polyimide is obtained by ring-closing the above polyimide precursor, and the ring-closing ratio of the amic acid group (also referred to as imidization ratio) in this polyimide is not necessarily 100%, and can be arbitrarily adjusted depending on the application and purpose. Examples of the method for imidizing the polyimide precursor include: thermal imidization by directly heating a solution of a polyimide precursor, or catalytic imidization by adding a catalyst to a solution of a polyimide precursor.

In the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having higher reliability is generally obtained as the imidization ratio is higher, but the polymer of the present invention has an imide ring derived from the 1 st diamine, and therefore, it is not always necessary to increase the imidization ratio. This is advantageous in improving the solubility and the reworkability.

The temperature for thermal imidization of the polyimide precursor in the solution is 100 to 400 ℃, preferably 120 to 250 ℃, and a method of removing water generated by the imidization reaction from the system is preferable. The catalyst imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at-20 to 250 ℃, preferably at 0 to 180 ℃.

The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, the amount of the basic catalyst is 1 to 50 times, preferably 3 to 30 times, the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, the amount of the acid amide group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity for allowing the reaction to proceed. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride (pyromelitic anhydride). In particular, the use of acetic anhydride is preferable because purification after completion of the reaction is easy. The imidization rate based on the catalyst imidization can be controlled by adjusting the amount of the catalyst, the reaction temperature, and the reaction time.

When the polyimide precursor or polyimide to be produced is recovered from the reaction solution of the polyimide precursor or polyimide, the reaction solution may be put into a solvent to precipitate the polyimide precursor or polyimide. Examples of the solvent used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer which is put into the solvent and precipitated may be dried under normal pressure or reduced pressure, or at normal temperature or by heating after being filtered and recovered. Further, when the polymer after the precipitation recovery is redissolved in a solvent and the operation of the reprecipitation recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent in this case include alcohols, ketones, and hydrocarbons. It is preferable to use three or more solvents selected from them because the purification efficiency is further improved.

< liquid Crystal Aligning agent >

The liquid crystal aligning agent of the present invention contains the above-mentioned polymer (hereinafter, also referred to as a specific polymer), and may contain two or more polymers having different structures. In addition, other polymers may be contained in addition to the polymer. Examples of the polymer form include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or a derivative thereof, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate. When the liquid crystal aligning agent of the present invention contains another polymer, the proportion of the specific polymer to the entire polymer component is preferably 5% by mass or more, and examples thereof include 5 to 95% by mass.

The liquid crystal aligning agent is usually in the form of a coating liquid in terms of forming a uniform thin film. The liquid crystal aligning agent of the present invention is also preferably a coating solution containing the above-mentioned polymer component and an organic solvent dissolving the polymer component. In this case, the concentration of the polymer in the liquid crystal aligning agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. The content of the inorganic oxide is preferably 1% by mass or more in terms of forming a uniform and defect-free coating film, and is preferably 10% by mass or less in terms of storage stability of the solution. The concentration of the polymer is particularly preferably 2 to 8 mass%.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N-dimethylacetamide, 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-cyclohexyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropane amide, 3-butoxy-N, N-dimethylpropane amide, γ -butyrolactam, dimethyl sulfoxide, γ -butyrolactone, γ -valerolactone, 1, 3-dimethyl-2-imidazolidinone, Methyl ethyl ketone, cyclohexanone, cyclopentanone, and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ -butyrolactone is preferably used.

In addition to the above-mentioned solvents, the organic solvent contained in the liquid crystal aligning agent of the present invention may be a solvent which improves coatability when the liquid crystal aligning agent is coated and surface smoothness of a coating film. Specific examples of the organic solvent include solvents described in paragraph [0177] of Japanese unexamined patent publication No. WO 2016-140328. Preferred specific examples thereof include the following solvents. 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, 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, diethylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutyl methanol (2, 6-dimethyl-4-heptanol), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, and the like.

The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent. Examples of such additional components include: an adhesion promoter for improving the adhesion between the liquid crystal alignment film and the substrate and the adhesion between the liquid crystal alignment film and the sealant; a crosslinking agent for improving the strength of the liquid crystal alignment film; a dielectric material or a conductive material for adjusting a dielectric constant or a resistance of the liquid crystal alignment film; and an imidization accelerator for efficiently performing imidization by heating a polyimide precursor when a coating film is fired. Specific examples of such additional components include crosslinkable compounds disclosed in paragraph [0104] on page 53 to paragraph [0116] on page 60 of International publication No. 2015/060357, and known crosslinking agents. Preferable specific examples of the crosslinking agent include compounds represented by the following formulas (CL-1) to (CL-11). The crosslinking agent is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of the polymers contained in the liquid crystal aligning agent.

Examples of the adhesion promoter for improving the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy-containing compound. Specific examples thereof include the compounds described in paragraph [0180] of Japanese unexamined patent publication WO 2016-140328.

< liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is obtained from the liquid crystal aligning agent. By using the liquid crystal aligning agent of the present invention, the following liquid crystal alignment film and liquid crystal display element can be provided: the liquid crystal display device is particularly suitable for a VA system in which liquid crystal molecules aligned perpendicularly to a substrate respond to an electric field, particularly for a PSA mode, and has excellent voltage holding ratio, rapid relaxation of accumulated charges, and excellent image retention characteristics. As an example of a method for obtaining a liquid crystal alignment film, a cured film obtained by: the liquid crystal aligning agent of the present invention is applied to a substrate, and then dried and fired as necessary to obtain a cured film. The cured film may be subjected to brushing, irradiation with polarized light, light of a specific wavelength, or the like, or treatment with an ion beam, or the like, and may be irradiated with UV in a state where a voltage is applied to a liquid crystal display element in which liquid crystal is filled as an alignment film for PSA. In particular, it is useful as an alignment film for PSA.

The substrate to which the liquid crystal aligning agent is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used together with a glass substrate or a silicon nitride substrate. In this case, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed, from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque material such as a silicon wafer may be used as a single-sided substrate, and in this case, a material that reflects light such as aluminum may be used as an electrode.

The method of applying the liquid crystal aligning agent is not particularly limited, and the method is generally industrially screen printing, offset printing, flexographic printing, inkjet printing, or the like. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray coating method, and the like, and these methods can be used according to the purpose. After coating the liquid crystal alignment agent on the substrate, the solvent is evaporated by a heating means such as a hot plate, a thermal cycle oven, or an IR (infrared) oven, and then fired. The drying and firing steps after the application of the liquid crystal aligning agent can be performed at any temperature and for any time. The drying step is not essential, but when the time from coating to firing is not constant depending on the substrate or when the substrate is not fired immediately after coating, the drying step is preferably performed. The drying is not particularly limited as long as the solvent is removed to such an extent that the shape of the coating film is not deformed by conveyance of the substrate or the like. For example, the drying may be performed for 0.5 to 30 minutes, preferably 1 to 5 minutes, on a hot plate at a temperature of 40 to 150 ℃, preferably 60 to 100 ℃.

The firing temperature of the coating film formed by applying the liquid crystal aligning agent is not limited, and is, for example, 100 to 350 ℃, preferably 120 to 300 ℃, and more preferably 150 to 250 ℃. The firing time is 5 to 240 minutes, preferably 10 to 90 minutes, and more preferably 20 to 90 minutes. The heating can be performed by a generally known method, for example, by using a hot plate, a hot air circulating furnace, an infrared furnace, or the like.

If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may be lowered, and therefore 5 to 300nm is preferable, and 10 to 200nm is more preferable. The liquid crystal alignment film of the present invention is useful as a liquid crystal alignment film for a liquid crystal display device of VA system, particularly PSA mode.

< liquid crystal display element and method for manufacturing the same >

In the liquid crystal display device, a liquid crystal alignment film is formed on a substrate by the above-described method, and then a liquid crystal cell is produced by a known method. A specific example of the liquid crystal display element is a vertical alignment mode (VA mode) liquid crystal display element including a liquid crystal cell having two substrates arranged to face each other, a liquid crystal layer provided between the substrates, and the liquid crystal alignment film formed of a liquid crystal alignment agent and provided between the substrates and the liquid crystal layer. A more preferred specific example is a vertical alignment type liquid crystal display element (the PSA mode liquid crystal display element) including a liquid crystal cell prepared as follows: the liquid crystal alignment film is formed by applying a liquid crystal alignment agent to two substrates and baking the applied liquid crystal alignment agent, the two substrates are arranged so that the liquid crystal alignment films face each other, a liquid crystal layer made of liquid crystal is sandwiched between the two substrates, that is, the liquid crystal layer is provided in contact with the liquid crystal alignment film, and ultraviolet rays are irradiated to the liquid crystal alignment film and the liquid crystal layer while applying a voltage.

The substrate of the liquid crystal display element is not particularly limited as long as it is a substrate having high transparency, and is usually a substrate on which a transparent electrode for driving liquid crystal is formed. Specific examples thereof include the same substrates as those described in the liquid crystal alignment film. However, in a liquid crystal display element, since a liquid crystal aligning agent containing the polyimide-based polymer of the present invention is used, for example, a line/slit electrode pattern of 1 μm to 10 μm is formed on one substrate, and the liquid crystal display element can operate even in a structure in which a slit pattern or a protrusion pattern is not formed on the opposite substrate.

Further, in a high-functional element such as a TFT-type element, a substrate in which an element such as a transistor can be formed between an electrode for liquid crystal driving and the substrate can be used.

In the case of a transmission type liquid crystal display element, a substrate as described above is generally used, but in a reflection type liquid crystal display element, if only a single-sided substrate is used, an opaque substrate such as a silicon wafer may be used. In this case, a material such as aluminum that reflects light may be used for the electrodes formed on the substrate.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display element is not particularly limited, and a liquid crystal material used in a conventional vertical alignment system, for example, a negative-type liquid crystal such as MLC-6608, MLC-6609, or MLC-3023 manufactured by MERCK corporation, can be used. In the PSA mode liquid crystal display device, for example, a polymerizable compound represented by the following formula can be used as the liquid crystal component.

As a method of sandwiching the liquid crystal layer between the two substrates, a known method can be mentioned. Examples of the method include the following: a pair of substrates on which liquid crystal alignment films are formed is prepared, spacers such as beads are dispersed on the liquid crystal alignment film of one substrate, the other substrate is bonded so that the surface on which the liquid crystal alignment film is formed is on the inside, and the liquid crystal is injected under reduced pressure and sealed. In addition, the liquid crystal cell can also be manufactured by the following method: a pair of substrates on which liquid crystal alignment films are formed is prepared, spacers such as beads are dispersed on the liquid crystal alignment film of one substrate, liquid crystal is dropped, and the other substrate is bonded so that the surface on which the liquid crystal alignment film is formed is on the inside, and sealing is performed. The thickness of the spacer is preferably 1 to 30 μm, and more preferably 2 to 10 μm.

Examples of the step of producing a liquid crystal cell by irradiating ultraviolet rays while applying a voltage to the liquid crystal alignment film and the liquid crystal layer include the following methods: an electric field is applied to the liquid crystal alignment film and the liquid crystal layer by applying a voltage between electrodes provided on the substrate, and ultraviolet rays are irradiated while maintaining the electric field. The voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The dose of the ultraviolet ray is, for example, 1 to 60J/cm²Preferably 40J/cm²Hereinafter, it is preferable that the smaller the amount of ultraviolet irradiation, the more the reduction in reliability due to the destruction of the members constituting the liquid crystal display element is suppressed, and the manufacturing efficiency is improved by reducing the ultraviolet irradiation time.

As described above, when ultraviolet rays are irradiated while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, the polymerizable compound reacts to form a polymer, and the polymer stores the direction in which the liquid crystal molecules are tilted, whereby the response speed of the obtained liquid crystal display element can be increased. Further, when ultraviolet rays are irradiated while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, since photoreactive side chains of at least one polymer selected from a polyimide precursor and a polyimide obtained by imidizing the polyimide precursor react with each other or the photoreactive side chains of the polymer react with a polymerizable compound contained in the liquid crystal layer, the response speed of the liquid crystal display element obtained can be increased, the polyimide precursor comprising: a side chain for aligning liquid crystals vertically, such as a2 nd diamine compound having a side chain structure represented by the above formulas [ S1] to [ S3], and the photoreactive side chain.

Next, the polarizing plate was disposed. Specifically, a pair of polarizing plates is preferably attached to the surfaces of the two substrates opposite to the liquid crystal layers.

The liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above-described configuration and manufacturing method as long as the liquid crystal alignment agent of the present invention is used, and can be manufactured by other known methods. The steps from the liquid crystal aligning agent to the liquid crystal display element are disclosed in, for example, Japanese patent laid-open No. 2015-135393 from [0074] on page 17 to [0082] on page 19.

Examples

< example >

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(diamine Compound)

p-PDA: p-phenylenediamine.

DA-1 to DA-9: are 1 st diamines (also referred to as specific diamines) represented by the following formulae DA-1 to DA-9, respectively. DA-1 to DA-6, DA-7 and DA-8 are novel compounds.

SC-1 to SC-4: side chain diamines represented by the following formulas SC-1 to SC-4.

(tetracarboxylic acid component)

CBDA: 1, 2, 3, 4-cyclobutanetetracarboxylic dianhydride.

BODA: bicyclo [3, 3, 0] octane-2, 4, 6, 8-tetracarboxylic dianhydride.

TCA: 2, 3, 5-tricarboxypentylalcetic acid dianhydride.

(solvent)

NMP: n-methyl-2-pyrrolidone.

BCS: butyl cellosolve.

THF: tetrahydrofuran.

DMF: n, N-dimethylformamide.

CH₂Cl₂: dichloromethane.

CHCl₃: chloroform.

＜¹Measurement of H-NMR

The device comprises the following steps: a Fourier transform superconducting nuclear magnetic resonance spectrometer (FT-NMR) AVANCE III (manufactured by BRUKER) has a frequency of 500 MHz.

Solvent: deuterated chloroform (CDCl)₃) Or deuterated N, N-dimethyl sulfoxide ([ D ]₆]－DMSO)。

Standard substance: tetramethylsilane (TMS).

< Synthesis of diamine >

(Synthesis example 1)

Synthesis of [ DA-1 ]:

n- (t-Butoxycarbonyl) -1, 4-phenylenediamine (39.4g, 189mmol) and NMP (394g) were placed in a 1L four-necked flask, and bicyclo [3, 3, 0] octane-2, 4, 6, 8-tetracarboxylic dianhydride (23.4g, 94mmol) was added to the flask in a water bath, followed by stirring at 60 ℃ for 6 hours. Subsequently, pyridine (89.2g, 1128mmol) and acetic anhydride (60.5g, 593mmol) were added to the reaction solution, and the mixture was stirred at 110 ℃. After completion of the reaction, the reaction system was poured into pure water (2500g), and the precipitate was filtered off. Then, the obtained crude product was isolated (isolation) by silica gel column chromatography (eluent: ethyl acetate), whereby 40.6g of [ DA-1-1 ] was obtained.

Into a 1L four-necked flask, [ DA-1 ]](33.8g, 54mmol) and CH₂Cl₂(510g) Trifluoroacetic acid (55.0g, 539mmol) was added dropwise to the water bath, followed by stirring at room temperature. After the reaction is finished, the precipitate is filtered and CH is utilized₂Cl₂(300g) The cleaning was performed. To the resulting crude product was added pure water (700g), neutralized with triethylamine (50g), and the precipitate was filtered off. To the obtained crude product were added DMF (50g) and methanol (500g), and repulping (repulping) washing was performed at room temperature to obtain [ DA-1 ]](white solid) 11.9 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-1 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ7.30－7.33(m，4H)，6.52－6.58(m，4H)，5.26(s，2H)，5.20(s，2H)，3.33(s，2H)，3.26－3.28(m，2H)，2.95－2.98(m，2H)，2.44－2.48(m，2H)，1.90－1.94(m，1H)，1.67－1.73(m，1H)。

(Synthesis example 2)

Synthesis of [ DA-2 ]:

A2L four-necked flask was charged with tert-butyl (3-aminophenyl) carbamate (83.4g, 400mmol) and NMP (840g), and bicyclo [3, 3, 0] octane-2, 4, 6, 8-tetracarboxylic dianhydride (46.6g, 186mmol) was added to the flask in a water bath, followed by stirring at 60 ℃ for 6 hours. Subsequently, pyridine (178.1g, 2250mmol) and acetic anhydride (115.5g, 1120mmol) were charged into the reaction solution, followed by stirring at 110 ℃. After completion of the reaction, the reaction system was poured into pure water (5000g), and the precipitate was filtered off. Then, the obtained crude product was isolated by silica gel column chromatography (eluent: ethyl acetate), whereby 103.5g of [ DA-2-1 ] was obtained.

Into a 2L four-necked flask was charged [ DA-2-1 ] obtained as described above](100.5g, 160mmol) and CH₂Cl₂(1500g) Trifluoroacetic acid (165.7g, 1620mmol) was added dropwise to the water bath, followed by stirring at room temperature. After the reaction is finished, the precipitate is filtered and CH is utilized₂Cl₂(600g) The cleaning was performed. To the resulting crude product was added pure water (2000g), neutralized with triethylamine (100g), and the precipitate was filtered off. To the obtained crude product were added DMF (100g) and methanol (1000g), followed by reslurrying and washing at room temperature to obtain [ DA-2 ]](white solid) 32.3 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-2 ]]。

1HNMR(500MHz，[D₆]－DMSO)：δ7.01－7.08(m，2H)，6.54－6.58(m，2H)，6.24－6.31(m，4H)，5.24(s，2H)，5.18(s，2H)，3.37(s，2H)，3.28－3.30(m，2H)，2.96－2.97(d，2H)，2.47－2.53(m，2H)，1.95－1.99(m，1H)，1.75－1.80(m，1H)。

(Synthesis example 3)

Synthesis of [ DA-3 ]:

n- (tert-Butoxycarbonyl) -1, 4-phenylenediamine (20.0g, 96mmol) and NMP (200g) were placed in a 1L four-necked flask, and 1, 2, 3, 4-butanetetracarboxylic dianhydride (8.6g, 43mmol) was added to a water bath, followed by stirring at 40 ℃ for 6 hours. Subsequently, pyridine (20.5g, 259mmol) and acetic anhydride (13.2g, 130mmol) were put into the reaction solution, and the mixture was stirred at 60 ℃. After completion of the reaction, the reaction system was poured into pure water (1000g), and the precipitate was filtered off. Then, THF (180g) and methanol (200g) were added to the obtained crude product, followed by reslurry washing at room temperature, whereby [ DA-3-1 ] was obtained.

Into a 1L four-necked flask was charged [ DA-3-1 ] obtained as described above](14.7g, 25mmol) and CH₂Cl₂(400g) Trifluoroacetic acid (43.3g, 380mmol) was added dropwise to the water bath, followed by stirring at room temperature. After completion of the reaction, hexane (1000g) was added to the reaction solution, and the precipitate was filtered off. Pure water (400g) was added to the obtained crude product, neutralized with pyridine (40g), and the precipitate was filtered off. DMF (10g) was added to the obtained crude product, followed by reslurrying and washing, and ethyl acetate (50g) was further added to the crude product, followed by reslurrying and washing at 60 ℃ to obtain [ DA-3 ]](white solid) 6.6 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-3 ]]。

1H NMR(400MHz，[D₆]－DMSO)：δ6.84－7.95(d，4H)，6.56－6.60(d，4H)，5.31(s，4H)，3.52－3.55(t，2H)，2.94－3.01(q，2H)，2.65－2.67(d，1H)，2.61－2.62(d，1H)。

(Synthesis example 4)

Synthesis of [ DA-4 ]:

into a 1L four-necked flask were charged N- (tert-butoxycarbonyl) -1, 4-phenylenediamine (33.3g, 160mmol) and NMP (330g), and then a bicyclo [2.2.2] octane-2, 3: 5, 6-Tetracarboxylic dianhydride (20.0g, 80mmol) was stirred at 60 ℃ for 6 hours. Subsequently, pyridine (38.0g, 480mmol) and acetic anhydride (24.5g, 240mmol) were put into the reaction solution, and the mixture was stirred at 110 ℃. After completion of the reaction, the reaction system was poured into pure water (1500g), and the precipitate was filtered off. Subsequently, the obtained crude product was isolated by silica gel column chromatography (eluent: ethyl acetate/hexane 2/1 (vol.)), and ethyl acetate (200g) was further added to the crude product, followed by reslurry washing at 50 ℃ to obtain 29.8g of [ DA-4-1 ].

Into a 1L four-necked flask, the [ DA-4-1 ] obtained in the above was charged](29.8g, 47mmol) and CHCl₃(440g) Trifluoroacetic acid (53.9g, 473mmol) was added dropwise to the water bath, followed by stirring at 50 ℃. After the reaction is finished, the precipitate is filtered off and CHCl is utilized₃(300g) And (5) cleaning. To the resulting crude product was added pure water (300g), neutralized with triethylamine (20g), and the precipitate was filtered off. DMF (180g) and methanol (180g) were added to the obtained crude product, and repulp washing was performed at room temperature to obtain 16.9g of [ DA-4 ]](white solid). The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-4 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ6.86－6.88(d，4H)，6.60－6.62(d，4H)，5.35(s，4H)，3.23(s，4H)，2.50(s，2H)，1.40(s，4H)。

(Synthesis example 5)

Synthesis of [ DA-5 ]:

n- (tert-Butoxycarbonyl) -1, 4-phenylenediamine (25.0g, 120mmol), pyridine (28.5g, 360mmol) and NMP (250g) were put in a 1L four-necked flask, and bicyclo [2.2.2] oct-7-ene-2, 3, 5, 6-tetracarboxylic dianhydride (14.9g, 60mmol) was added to the flask in a water bath, followed by stirring at 80 ℃. After completion of the reaction, the reaction system was poured into pure water (1500g), and the precipitate was filtered off. Subsequently, methanol (1500g) was added to the obtained crude product, followed by reslurry washing at room temperature, whereby 30.6g of [ DA-5-1 ] was obtained.

Into a 1L four-necked flask, [ DA-5-1 ]](30.6g, 49mmol) and CHCl₃(300g) Trifluoroacetic acid (55.5g, 487mmol) was added dropwise to the water bath, followed by stirring at 50 ℃. After the reaction is finished, the precipitate is filtered off and CHCl is utilized₃(100g) And (5) cleaning. Methanol (250g) was added to the resulting crude product, neutralized with triethylamine (20g), and the precipitate was filtered off. Methanol (100g) was added to the obtained crude product, and repulping and washing were conducted at room temperature to obtain [ DA-5 ]](white solid) 20.0 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was [ DA-5 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ6.70－6.74(d，4H)，6.55－6.58(d，4H)，6.23－6.24(q，2H)，5.34(d，4H)，3.45－3.47(s，2H)，3.30(s，4H)。

(Synthesis example 6)

Synthesis of [ DA-6 ]:

into a 1L four-necked flask were charged N- (tert-butoxycarbonyl) -1, 4-phenylenediamine (25.0g, 120mmol) and NMP (250g), and 1R, 2S, 4S, 5R-cyclohexanetetracarboxylic anhydride (13.5g, 60mmol) was added in a water bath, followed by stirring at 50 ℃ for 6 hours. Subsequently, pyridine (28.5g, 360mmol) and acetic anhydride (18.5g, 180mmol) were put into the reaction solution, and the mixture was stirred at 50 ℃. After completion of the reaction, the reaction system was poured into pure water (1500g), and the precipitate was filtered off. Subsequently, methanol (150g) was added to the obtained crude product, followed by reslurry washing at room temperature, whereby 15.4g of [ DA-6-1 ] was obtained.

Into a 1L four-necked flask was charged [ DA-6-1 ] obtained as described above](15.4g, 26mmol) and CHCl₃(154g) Trifluoroacetic acid (29.1g, 255mmol) was added dropwise to the water bath, followed by stirring at 50 ℃. After the reaction is finished, the precipitate is filtered off and CHCl is utilized₃(50g) And (5) cleaning. To the crude product obtainedPure water (200g) was added, neutralized with triethylamine (10g), and the precipitate was filtered, whereby [ DA-6 ] was obtained](white solid) 9.9 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-6 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ6.86－6.88(d，4H)，6.59－6.62(d，4H)，5.33(s，4H)，3.04－3.06(t，4H)，2.11(s，4H)。

(Synthesis example 7)

Synthesis of [ DA-7 ]:

n- (tert-Butoxycarbonyl) -1, 4-phenylenediamine (33.3g, 160mmol) and NMP (300g) were placed in a 1L four-necked flask, and tetrahydro-3, 3 '-dimethyl [3, 3' -difuran ] -2, 2 ', 5, 5' -tetraone (17.2g, 76mmol) was added to the flask in a water bath, followed by stirring at 40 ℃ for 6 hours. Subsequently, pyridine (36.4g, 460mmol) and acetic anhydride (23.5g, 230mmol) were charged into the reaction solution, and the mixture was stirred at 60 ℃. After completion of the reaction, the reaction system was poured into pure water (1500g), and the precipitate was filtered off. Subsequently, the obtained crude product was isolated by silica gel column chromatography (eluent: ethyl acetate/hexane 1/1 (volume ratio)), and methanol (50g) was added to the obtained crude product, followed by reslurry and washing at room temperature, whereby 4.6g of [ DA-7-1 ] was obtained.

Into a 1L four-necked flask was charged [ DA-7-1 ] obtained as described above](4.6g, 8mmol) and CHCl₃(50g) Trifluoroacetic acid (17.2g, 152mmol) was added dropwise to the water bath, followed by stirring at 50 ℃. After completion of the reaction, hexane (150g) was added to the reaction solution, and the precipitate was filtered off. To the resulting crude product was added pure water (30g), triethylamine (2g) was added and neutralized, and the mixture was poured into ethyl acetate (200 g). The organic layer was washed with pure water (300g) and concentrated. Hexane (30g) was added to the obtained crude product, and repulp washing was performed at room temperature, whereby [ DA-7 ] was obtained](white solid) 2.7 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed thatTo the solid being the target [ DA-7]。

1H NMR(500MHz，[D₆]－DMSO)：δ6.84－6.86(d，4H)，6.58－6.59(d，4H)，5.31(s，4H)，2.98－3.00(d，2H)，2.67－2.71(d，2H)，1.45(s，6H)。

(Synthesis example 8)

Synthesis of [ DA-8 ]:

4, 4' - (ethane-1, 2-diylbis (oxy)) diphenylamine (109.5g, 448mmol) and DMF (850g) were charged into a 2L four-necked flask, and di-tert-butyl dicarbonate (32.8g, 151mmol) was added dropwise to the flask in a water bath, followed by stirring at room temperature. After completion of the reaction, the reaction mixture was concentrated, and the obtained residue was separated by silica gel column chromatography (eluent: ethyl acetate/hexane: 1/1 (volume ratio)), whereby 45.3g of [ DA-8-1 ] was obtained.

[ DA-8-1 ] (44.7g, 130mmol) and NMP (450g) were put in a 1L four-necked flask, bicyclo [3, 3, 0] octane-2, 4, 6, 8-tetracarboxylic dianhydride (23.4g, 94mmol) was added to the flask in a water bath, and then the mixture was stirred at 60 ℃ for 6 hours. Subsequently, pyridine (58.1g, 735mmol) and acetic anhydride (38.2g, 374mmol) were charged into the reaction solution, and the mixture was stirred at 110 ℃. After completion of the reaction, the reaction system was poured into pure water (4000g), and the precipitate was filtered off. Subsequently, DMF (250g) was added to the obtained crude product, and repulp washing was performed at 70 ℃ to obtain 36.8g of [ DA-8-2 ].

Into a 1L four-necked flask, [ DA-8-2 ]](36.8g, 41mmol) and CHCl₃(750g) Trifluoroacetic acid (46.8g, 410mmol) was added dropwise to the water bath, followed by stirring at 50 ℃. After completion of the reaction, the reaction mixture was poured into hexane (750g), and the precipitate was filtered off. To the resulting crude product was added methanol (1200g), triethylamine (50g) was added and neutralized, and the precipitate was filtered off. Subsequently, methanol (1200g) was added to the obtained crude product, and repulping and washing were performed at room temperature, whereby [ DA-8 ] was obtained](white solid) 26.3 g. The following shows the results of 1H-NMR of the target compound. According toAs a result, it was confirmed that the obtained solid was the target [ DA-8 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ7.00－7.11(m，8H)，6.69－6.71(d，4H)，6.51－6.53(d，4H)，4.64(s，4H)，4.27－4.28(d，4H)，4.16－4.17(d，4H)，3.40(s，2H)，3.34(s，2H)，3.00－3.01(d，2H)，2.56－2.59(d，2H)，1.94－1.97(d，1H)，1.72－1.75(d，1H)。

(Synthesis example 9)

Synthesis of [ DA-9 ]:

into a 1L four-necked flask were charged N- (tert-butoxycarbonyl) -1, 4-phenylenediamine (20.0g, 96mmol) and NMP (200g), and 3- (carboxymethyl) -1, 2, 4-cyclopentanetricarboxylic acid 1, 4: 2, 3-dianhydride was then stirred at 60 ℃ for 6 hours. Subsequently, pyridine (22.8g, 288mmol) and acetic anhydride (14.7g, 144mmol) were put into the reaction solution, followed by stirring at 110 ℃. After completion of the reaction, the reaction system was poured into pure water (1000g), and the precipitate was filtered off. Subsequently, the obtained crude product was isolated by silica gel column chromatography (eluent: ethyl acetate/hexane 2/1 (volume ratio)), and methanol (300g) was further added to the crude product, followed by reslurry and washing at room temperature to obtain 15.6g of [ DA-9-1 ].

Into a 1L four-necked flask, [ DA-9-1 ]](15.6g, 26mmol) and CH₂Cl₂(230g) Trifluoroacetic acid (29.3g, 257mmol) was added dropwise to the water bath, followed by stirring at room temperature. After the reaction is finished, the precipitate is filtered and CH is utilized₂Cl₂(200g) And (5) cleaning. Pure water (100g) was added to the obtained crude product, neutralized with pyridine (5g), and the precipitate was filtered off. To the obtained crude product were added DMF (30g) and methanol (300g), and repulp washing was performed at room temperature, whereby [ DA-9 ] was obtained](white solid) 8.3 g. The following shows the results of 1H-NMR of the target compound. From the results, it was confirmed that the obtained solid was the target [ DA-9 ]]。

1H NMR(500MHz，[D₆]－DMSO)：δ6.74－6.77(m，4H)，6.53－6.56(d，4H)，5.21－5.22(d，4H)，3.72－3.75(d，1H)，3.51(s，1H)，3.03(s，2H)，2.91－2.99(m，1H)，2.75－2.81(m，1H)，2.38－2.41(d，1H)，2.14－2.17(m，1H)。

< preparation of liquid Crystal Aligning agent >

(reference example 1)

DA-1 (4.30g, 10.0mmol) was dissolved in NMP (17.2g), and after stirring at 40 ℃ for 30 minutes, CBDA (1.82g, 9.3mmol) and NMP (7.3g) were added, and the mixture was reacted at 40 ℃ for 12 hours to obtain a polyamic acid solution (A).

To the polyamic acid solution (A) (15.0g) were added NMP (25.0g) and BCS (10.0g), and the mixture was stirred at room temperature for 5 hours, thereby obtaining a liquid crystal aligning agent (A1).

(reference examples 2 to 9)

Liquid crystal alignment agents B1 to I1 were prepared in the same manner as in reference example 1, except that the diamine of item 1 was changed as shown in Table 1.

Comparative reference example 1

A liquid crystal aligning agent J1 was prepared in the same manner as in reference examples 1 to 9, except that the specific diamine was changed to p-PDA.

[ Table 1]

< manufacture of liquid Crystal cell >

(reference example 10)

The liquid crystal aligning agent (A1) obtained in reference example 1 was spin-coated on the ITO surface of a 3cm X4 cm ITO-equipped glass substrate, and the substrate was baked at 80 ℃ for 1 minute and 30 seconds using a hot plate, and then baked in an infrared heating furnace at 230 ℃ for 20 minutes to produce a polyimide coated substrate having a film thickness of 100 nm.

Two polyimide-coated substrates were prepared by the above method, and after spreading 4 μm bead spacers on the liquid crystal alignment film surface of one substrate, a thermosetting sealant (XN-1500T, manufactured by coviki chemical corporation) was printed thereon. Next, the other substrate was bonded to the previous substrate with the surface on which the liquid crystal alignment film was formed being the inner side, and then the sealant was cured to produce an empty cell. The empty cell was filled with liquid crystal MLC-3023 (trade name, manufactured by MERCK) containing a polymerizable compound for PSA by a reduced pressure injection method to prepare a liquid crystal cell. The voltage holding ratio of the liquid crystal cell was measured.

Then, the cell was irradiated with a DC voltage of 15V from the outside thereof to a depth of 10J/cm²UV passed through a 325nm cut-off filter (also referred to as primary PSA treatment). The UV illuminance was measured by using UV-MO 3A manufactured by ORC.

Then, in order to inactivate the unreacted polymerizable compound remaining in the liquid crystal cell, UV (UV lamp: FLR40SUV 32/A-1) was irradiated for 30 minutes (referred to as secondary PSA treatment) with no voltage applied using a UV-FL irradiation apparatus manufactured by Toshiba LIGHT Inc. Then, the voltage holding ratio was measured.

< evaluation of Voltage holding ratio >

The liquid crystal cell prepared above was applied with a voltage of 1V for 60. mu.s in a hot air circulating oven at 60 ℃, and then the voltage after 1667msec was measured to calculate how much the voltage could be held as a voltage holding ratio. VHR-1 manufactured by Toyang technology corporation was used for the measurement of the voltage holding ratio.

(reference examples 11 to 15)

VHR was measured in the same manner as in reference example 10 except that the liquid crystal aligning agents (B1), (C1), (E1), (F1) and (I1) were used instead of the liquid crystal aligning agent (a 1).

Comparative reference example 2

VHR was measured in the same manner as in reference example 10 except that the liquid crystal aligning agent (J1) was used instead of the liquid crystal aligning agent (a 1).

The results of VHR measurement are shown below.

[ Table 2]

As shown in table 2, VHR was 20% or less from the beginning and very low in comparative reference example 2, whereas VHR was 60% or more of good results even after the secondary PSA treatment in reference examples 10 to 15. From the results, it was found that the liquid crystal aligning agent into which the specific diamine was introduced can ensure higher driving reliability than the liquid crystal aligning agent not introduced.

(example 1)

DA-1 (2.15g, 5.0mmol) and SC-1 (1.90g, 5.0mmol) were dissolved in NMP (16.2g), and after stirring at 40 ℃ for 30 minutes, CBDA (1.82g, 9.3mmol) and NMP (7.3g) were added, and the mixture was reacted at 40 ℃ for 12 hours to obtain a polyamic acid solution (K).

To the polyamic acid solution (K) (15.0g) were added NMP (20.0g) and BCS (15.0g), and the mixture was stirred at room temperature for 5 hours, thereby obtaining a liquid crystal aligning agent (K1).

(examples 2 to 9)

Liquid crystal alignment agents L1 to S1 were prepared in the same manner as in example 1, except that the specific diamine (1 st diamine) and the side chain diamine (2 nd diamine) were changed as shown in table 3.

(example 10)

DA-1 (3.23g, 7.5mmol) and SC-4 (1.90g, 2.5mmol) were dissolved in NMP (20.5g), and after stirring at 40 ℃ for 30 minutes, TCA (2.20g, 9.8mmol) and NMP (8.8g) were added and reacted at 60 ℃ for 10 hours to obtain a polyamic acid solution (T).

To the polyamic acid solution (T) (15.0g) were added NMP (20.0g) and BCS (15.0g), and the mixture was stirred at room temperature for 5 hours, thereby obtaining a liquid crystal aligning agent (T1).

(example 11)

DA-5 (2.83g, 7.0mmol) and SC-2 (1.30g, 3.0mmol) were dissolved in NMP (16.5g), and after stirring at 40 ℃ for 30 minutes, BODA (1.88g, 7.5mmol) and NMP (7.5g) were added, and the mixture was reacted at 60 ℃ for 5 hours. Then, CBDA (0.45g, 2.3mmol) and NMP (1.8g) were added thereto and reacted at 40 ℃ for 12 hours to obtain a polyamic acid solution (U).

To the polyamic acid solution (U) (15.0g) were added NMP (20.0g) and BCS (15.0g), and the mixture was stirred at room temperature for 5 hours, thereby obtaining a liquid crystal aligning agent (U1).

(examples 12 and 13)

Liquid crystal alignment agents V1 and W1 were prepared in the same manner as in example 11, except that the specific diamine, side chain diamine, and tetracarboxylic acid components were changed as shown in table 3.

[ Table 3]

< preparation of sample for evaluating seal adhesion >

The liquid crystal aligning agent (K1) obtained in example 1 was filtered through a filter having a pore size of 1.0 μm, spin-coated on a glass substrate having a transparent electrode, dried on a hot plate at 80 ℃ for 2 minutes, and then baked at 230 ℃ for 20 minutes to obtain a coating film having a thickness of 100 nm. Two substrates thus obtained were prepared, and a spacer of beads having a diameter of 4 μm was spread on the liquid crystal alignment film surface of one of the substrates, followed by dropwise addition of a sealing agent (XN-1500T, Co., Ltd.). Then, the substrates were bonded so that the liquid crystal alignment film surface of the other substrate was set to be the inner side and the overlapping width of the substrates was 1 cm. At this time, the amount of the sealant to be dropped was adjusted so that the diameter of the applied sealant was about 3 mm. After fixing the two substrates bonded to each other with a jig, the substrates were thermally cured at 120 ℃ for 1 hour to prepare a sample for evaluating adhesiveness.

< measurement of seal adhesion >

The prepared sample was fixed to the end portions of the upper and lower substrates by a bench-top precision universal testing machine AGS-X500N manufactured by Shimadzu corporation, and then pressed from above the center of the substrate to measure the pressure (N) at the time of peeling. Then, the adhesion was evaluated using a value obtained by normalizing the pressure (N) for the measured diameter of the sealant.

< preparation of sample for evaluating reworking characteristics >

(test example 1)

The liquid crystal aligning agent (K1) obtained in example 1 was filtered through a filter having a pore size of 1.0 μm, and then spin-coated on a 3cm X4 cm glass substrate having an ITO electrode, dried on a hot plate at 80 ℃ for 2 minutes, and then baked at 230 ℃ for 30 minutes to obtain a substrate having a liquid crystal alignment film with a film thickness of 100 nm.

< evaluation of reworking Property >

The substrate with the liquid crystal alignment film was immersed in a 50mL beaker containing 15g of NMP for 30 seconds. At this time, it was confirmed that a part of the coated liquid crystal alignment film was immersed in NMP. After 30 seconds, NMP adhered to the substrate was washed off with pure water, and it was visually confirmed whether or not the liquid crystal alignment film remained in the portion immersed in NMP. The case where the liquid crystal alignment film in the portion immersed in NMP completely disappeared was defined as good reworkability, and the case where the liquid crystal alignment film remained or partially remained was defined as poor reworkability.

(test examples 2 to 13)

The same operations as in test example 1 were carried out except that the liquid crystal aligning agent (K1) was changed to those of examples 2 to 13, and the seal adhesion and the reworking characteristics were evaluated.

(comparative test examples 1 to 10)

The same operations as in example 1 were carried out except that the liquid crystal aligning agent (K1) was changed to those of reference examples 1 to 9 and comparative reference example 1, and the seal adhesion and the reworking property were evaluated.

(results of test examples)

The results of seal adhesion and reworking characteristics are shown below.

[ Table 4]

The results of the excellent reworking properties were obtained in test examples 1 to 13, which were tested using the liquid crystal aligning agents of examples 1 to 13, in which a side chain diamine was introduced together with a specific diamine, as compared to comparative test examples 1 to 10, which were tested using a liquid crystal aligning agent using only a specific diamine.

Claims

1. A liquid crystal aligning agent characterized in that,

comprising a polymer obtained from a diamine component comprising: at least one 1 st diamine represented by the following formula [ I ]; at least one 2 nd diamine having a side chain structure selected from the group consisting of the following formulas [ S1] to [ S3],

in the formula [ I]In, Z¹Selected from the following formula [ Z-1]～[Z－9]And represents a bonding bond,

formula [ S1]In, X¹And X²Each independently represents a single bond, - (CH)₂)_a－、－CONH－、－NHCO－、－CON(CH₃) -, -NH-, -O-, -COO-, -OCO-or- ((CH)₂)_a1－A₁)_m1-, said- (CH)₂)_aIn the formula (A), a represents an integer of 1-15, and the- ((CH)₂)_a1－A₁)_m1Wherein a1 is an integer of 1 to 15, A₁Represents an oxygen atom or-COO-, m₁Is an integer of 1 to 2 in m₁In the case of 2, a plurality of a1 and A₁Each independently has the above definitions; g¹And G²Each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms; the optional hydrogen atom on the cyclic group is selected from alkyl with 1-3 carbon atoms, alkoxy with 1-3 carbon atoms and C1 to 3 fluorine-containing alkyl groups, 1 to 3 carbon atoms fluorine-containing alkoxy groups, or fluorine atoms; m and n are respectively and independently integers of 0-3, and the sum of m and n is 1-6; r¹Represents 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 to form R¹Optionally substituted with fluorine atoms,

-X³-R² [S2]

formula [ S2]In, X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)－、－NH－、－O－、－CH₂O-, -COO-or-OCO-; r²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine atoms;

-X⁴-R³ [S3]

formula [ S3]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-; r³Represents a structure having a steroid skeleton.

2. The liquid crystal aligning agent according to claim 1,

the polymer is at least one polymer selected from the group consisting of a polyimide precursor which is a polycondensate of the diamine component and a tetracarboxylic dianhydride, and a polyimide which is an imide compound of the polyimide precursor.

3. The liquid crystal aligning agent according to claim 1 or 2,

the side chain structure represented by the formula [ S1] is at least one selected from the group consisting of the following formulas [ S1-x 1] to [ S1-x 7],

formula [ S1-x 1]]～[S1－x7]In, R¹Represents carbonAn alkyl group having 1 to 20 atoms; x^pIs represented by- (CH)₂)_a－、－CONH－、－NHCO－、－CON(CH₃)－、－NH－、－O－、－CH₂O－、－CH₂OCO－、－O－(CH₂)_m-O-, -COO-or-OCO-, the- (CH)₂)_aIn the formula, a is an integer of 1 to 15, and the formula is-O- (CH)₂)_m-O-, wherein m is an integer of 1 to 6; a. the₁Represents an oxygen atom or-COO-, wherein the bond with the "+" is bonded to (CH)₂)_a2Bonding; a. the₂Represents an oxygen atom or-COO-, wherein the bond with the "+" is bonded to (CH)₂)_a2Bonding; a3 is an integer of 0 or 1, a1 and a2 are each independently an integer of 2-10; cy represents a1, 4-cyclohexylene group or a1, 4-phenylene group.

4. The liquid crystal aligning agent according to any one of claims 1 to 3,

in the formula [ S2]In the diamines of the side chain structure shown, X³is-CONH-, -NHCO-, -O-, -CH₂O-, -COO-or-OCO-, R²Is an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms.

5. The liquid crystal aligning agent according to any one of claims 1 to 4,

the side chain structure represented by the formula [ S3] has a structure represented by the following formula [ S3-x ],

in the formula [ S3-X ], X represents the formula [ X1] or the formula [ X2 ]; col represents any group selected from the group consisting of formulas [ Col1] to [ Col3 ]; g represents an arbitrary group selected from the group consisting of the formulas [ G1] to [ G4 ]; in these formulae, denotes a bonding site; me represents a methyl group.

6. The liquid crystal aligning agent according to any one of claims 1 to 5,

the diamine component contains at least one diamine selected from the group consisting of diamines represented by the following formulae [1] and [2],

formula [1]In which Y represents a group selected from the formula [ S1]]～[S3]Monovalent groups in the side chain structures shown; in the formula [2]Wherein X represents a single bond, -O-, -C (CH)₃)₂－、－NH－、－CO－、－(CH₂)_m－、－SO₂－、－O－(CH₂)_m－O－、－O－C(CH₃)₂－、－CO－(CH₂)_m－、－NH－(CH₂)_m－、－SO₂－(CH₂)_m－、－CONH－(CH₂)_m－、－CONH－(CH₂)_m－NHCO－、－COO－(CH₂)_m－OCO－、－CONH－、－NH－(CH₂)_m-NH-, or-SO₂－(CH₂)_m－SO₂-; m is an integer of 1-8; two Y' S each independently represent a group selected from the formula [ S1]～[S3]Monovalent groups in the side chain structures shown.

7. A liquid crystal alignment film characterized in that,

a liquid crystal aligning agent according to any one of claims 1 to 6.

8. A liquid crystal display element is characterized in that,

a liquid crystal alignment film according to claim 7.

9. A diamine, characterized in that,

the diamine is represented by the following formula [ II ],

in the formula [ II]In, Z²Selected from the following formula [ Z-1]～[Z－4]、[Z－6]And [ Z-7](ii) a The symbol x represents a bonding bond,

10. diamine according to claim 9, characterized in that,

the diamine is represented by the following formula,