阅读说明：本技术 液晶取向剂、液晶取向膜、液晶显示元件以及二胺 (Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display element, and diamine ) 是由 山本雄介 福田一平 藤枝司 名木达哉 石井秀则 于 2020-03-11 设计创作，主要内容包括：本发明的目的在于提供一种残像的产生少、即使在发生由间隔物引起的刮蹭等物理上的摩擦时也能使亮点成为最小、可靠性高的液晶取向膜,可得到该液晶取向膜的液晶取向剂、以及具备该液晶取向膜的液晶显示元件。本发明为具有下述式(1)所示的结构的二胺、由其得到的聚合物以及含有该聚合物的液晶取向剂。式(1)中,A表示氢原子、碳原子数1～3的烷基、苄基、对甲氧基苄基、碳原子数1～3的烷氧基、乙酰基、苯甲酰基、叔丁氧基羰基、9－芴基甲氧基羰基或R-(1)R-(2)R-(3)Si基,R-(1)、R-(2)以及R-(3)分别独立地表示碳原子数1～3的烷基或苯基。(The invention aims to provide a liquid crystal alignment film which is low in generation of afterimages, can minimize bright spots even when physical friction such as scratch caused by a spacer occurs, and is high in reliability, a liquid crystal alignment agent for obtaining the liquid crystal alignment film, and a liquid crystal display element with the liquid crystal alignment film. The present invention relates to a diamine having a structure represented by the following formula (1), a polymer obtained therefrom, and a liquid crystal aligning agent containing the polymer. In the formula (1), A represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an alkoxy group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group or R 1 R 2 R 3 Si radical, R 1 、R 2 And R 3 Each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.)

1. A liquid crystal aligning agent comprising a polymer obtained from a diamine having a structure represented by the following formula (1),

in the formula (1), A represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an alkoxy group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group or R₁R₂R₃Si radical, R₁、R₂And R₃Each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.

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

the polymer is at least one selected from a polyimide precursor containing a structural unit represented by the following formula (6) and a polyimide which is an imide compound of the polyimide precursor,

in the formula (6), X₁Being a tetravalent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a divalent organic group derived from a diamine comprising the structure of formula (1), R₄Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

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

in the formula (6), X₁The structure of (a) is at least one selected from the following structures,

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

the structural unit represented by the formula (6) is 10 mol% or more based on the total structural units of the polymer.

5. A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of claims 1 to 4.

6. A liquid crystal display element comprising the liquid crystal alignment film according to claim 5.

7. A diamine having a structure represented by the following formula (1),

in the formula (1), A represents an alkyl group having 1 to 3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an alkoxy group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group or R₁R₂R₃Si radical, R₁、R₂And R₃Each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.

8. A polymer obtained by using the diamine according to claim 7.

Technical Field

The present invention relates to a polymer for a liquid crystal display element, a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element, and a novel diamine used therefor.

Background

In liquid crystal display elements, various driving methods such as electrode structures, physical properties of liquid crystal molecules used, and manufacturing processes have been developed, and for example, there are known: liquid crystal display elements such as TN (twisted nematic) type, STN (super-twisted nematic) type, VA (vertical alignment) type, MVA (multi-domain vertical alignment) type, IPS (in-plane switching) type, FFS (fringe field switching) type, and PSA (polymer-sustained alignment) type.

These liquid crystal display elements are provided with a liquid crystal alignment film for aligning liquid crystal molecules. A coating film made of a polymer such as polyamic acid, polyimide, or polysiloxane is generally used as a material of the liquid crystal alignment film in view of satisfactory properties such as heat resistance, mechanical strength, and affinity for liquid crystal.

In recent years, there has been an increasing demand for high image quality of liquid crystal display elements. In particular, in a display of a medical device or a liquid crystal television, a residual image, that is, a so-called "residual image" becomes a big problem when the device is driven for a long time, and there is a high demand for reducing the residual image. From the viewpoint of further improving the quality of the liquid crystal display element, it is desirable to obtain a liquid crystal display element in which an afterimage is less likely to be generated than in the past.

In view of such circumstances, a liquid crystal alignment film and a liquid crystal alignment agent that provide a liquid crystal display element excellent in reducing image sticking are known (for example, see patent documents 1, 2, and 3).

Further, the liquid crystal display element in the above-mentioned applications is also required to have a characteristic of withstanding long-term use under severe use environments, and patent document 4 discloses that a liquid crystal alignment agent containing a specific compound can provide a liquid crystal alignment film with little decrease in voltage holding ratio even after long-term exposure to a backlight, and a liquid crystal display element with high reliability can be obtained.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2016/063834 pamphlet

Patent document 2: international publication No. 2015/060366 pamphlet

Patent document 3: japanese patent laid-open publication No. 2018-054761

Patent document 4: international publication No. 2010/074269 pamphlet

Disclosure of Invention

Problems to be solved by the invention

In addition, since a so-called touch panel type liquid crystal display element is widely used, a user frequently performs such a behavior that a strong pressing force is applied to the display element with a finger. At this time, the spacers present inside the liquid crystal display element move inside the liquid crystal display element, and scratch the liquid crystal alignment film. The following technical problems are solved: the liquid crystal alignment film to which pressure is applied by the spacer cannot restrict the alignment of the liquid crystal, and light leaks from the peripheral portion of the spacer and appears as a bright spot (bright spot) even when the liquid crystal display element is caused to perform, for example, black display.

The structure of the liquid crystal aligning agent proposed in the related art cannot necessarily achieve all of the above-described problems. The present invention has been made in view of the above circumstances, and an object thereof is to provide a highly reliable liquid crystal display element that minimizes the occurrence of afterimages and minimizes the occurrence of bright spots even when physical rubbing such as scraping due to spacers occurs. Further, a liquid crystal alignment film having high film strength suitable for such a liquid crystal display element and a liquid crystal aligning agent thereof are provided.

In recent liquid crystal display devices, in order to enlarge the effective pixel area, it is required that a so-called frame region is made smaller without forming pixels in the peripheral outer edge portion on the substrate. As the frame of the panel is narrowed, a sealant used when two substrates are bonded to each other to manufacture a liquid crystal display element is applied to a polyimide liquid crystal alignment film, but the following problems occur: since polyimide has no polar group, covalent bonding with the sealant cannot be established on the surface of the liquid crystal alignment film, and adhesion between substrates is insufficient. Therefore, it is a problem to improve the adhesion (adhesiveness) between the polyimide liquid crystal alignment film and the sealant or the substrate.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that various properties are improved while introducing a specific structure into a polymer contained in a liquid crystal aligning agent, thereby completing the present invention. The present invention is based on the above findings, and the gist thereof is as follows.

1. A liquid crystal aligning agent contains a polymer obtained from a diamine having a structure represented by the following formula (1).

In the formula (1), A represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a benzyl group, a p-methoxybenzyl group, an alkoxy group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, a tert-butoxycarbonyl group, a 9-fluorenylmethoxycarbonyl group or R₁R₂R₃Si radical, R₁、R₂And R₃Each independently represents an alkyl group having 1 to 3 carbon atoms or a phenyl group.

Effects of the invention

According to the liquid crystal aligning agent of the present invention, a liquid crystal display element which generates little afterimage and can minimize bright spots even when physical rubbing such as scratch due to spacers occurs, and a liquid crystal alignment film providing the effect can be obtained.

According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent adhesion to a sealant can be obtained. By using the liquid crystal alignment film, a liquid crystal display element having excellent adhesion between substrates and high impact resistance can be obtained. The mechanism of improving the adhesion to the sealant is not necessarily clear, but is considered as follows: the hydroxyl group, methoxy group, or hydroxyl group generated by removing a protective group by heating, which is contained in the specific diamine, is exposed on the surface of the liquid crystal alignment film, and the group interacts with a functional group in the sealant, thereby improving the adhesion between the liquid crystal alignment film and the sealant.

Detailed Description

The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing a polymer (hereinafter, also referred to as a specific polymer) obtained from a diamine having a structure represented by the above formula (1). Hereinafter, each condition is described in detail.

< diamine having a specific Structure >

The polymer of the present invention is a polymer obtained from a diamine having the structure of the above formula (1).

Specific examples of the diamine of the formula (1) include, but are not limited to, the following. Among them, (1-1), (1-2) and (1-3) are particularly preferable from the viewpoint of moderating the accumulated charge.

< Polymer >

The polymer of the present invention is a polymer obtained by using the diamine. Specific examples thereof include polyamic acids, polyamic acid esters, polyimides, polyureas, and polyamides, but from the viewpoint of use as a liquid crystal aligning agent, at least one selected from polyimide precursors comprising a structural unit represented by the following formula (6) and polyimides which are imide compounds of the polyimide precursors is more preferable.

In the above formula (6), X₁Being a tetravalent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a divalent organic group derived from a diamine comprising the structure of formula (1), R₄Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. From the viewpoint of easiness of imidation by heating, R₄Preferably a hydrogen atom, methyl group or ethyl group.

Tetra carboxylic acid dianhydride

X₁Is a tetravalent organic group derived from a tetracarboxylic acid derivative, and the structure thereof is not particularly limited. Further, X in the polyimide precursor₁The amount of the polymer to be used may be appropriately selected depending on the solubility of the polymer in a solvent, the coatability of a liquid crystal aligning agent, the degree of characteristics required for forming a liquid crystal alignment film such as alignment properties of liquid crystal, voltage holding ratio, and accumulated charge.

If X is shown₁Specific examples of (A) include structures of formulae (X-1) to (X-46) described in claims 13 to 14 of International patent application publication No. 2015/119168.

Preferred X is shown below₁The present invention is not limited to the structure of (1).

Among the above-mentioned structures, (A-1) and (A-2) are particularly preferable from the viewpoint of photo-alignment properties, etc., (A-4) is particularly preferable from the viewpoint of further increasing the relaxation rate of accumulated charges, etc., (A-15) to (A-17) are particularly preferable from the viewpoint of liquid crystal alignment properties and further increasing the relaxation rate of accumulated charges, etc.

< polymer (other structural unit) >)

The polyimide precursor containing the structural unit represented by formula (6) may contain at least one selected from the structural unit represented by formula (7) below and a polyimide as an imide compound thereof, within a range not impairing the effects of the present invention.

In formula (7), X₂Being a tetravalent organic radical derived from a tetracarboxylic acid derivative, Y₂Is a divalent organic group derived from a diamine not comprising the structure of formula (1) in the main chain direction, R₅And R of said formula (6)₄Are as defined for R₆Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. In addition, R of two₆At least one of them is preferably a hydrogen atom.

As X₂Specific examples of (3) include: and X in the formula (6) including preferred examples₁The illustrated structures are the same. Further, Y in the polyimide precursor₂Is a divalent organic group derived from a diamine not containing the structure of formula (1) in the main chain direction, and the structure thereof is not particularly limited. Furthermore, Y₂The amount of the polymer to be used may be appropriately selected depending on the solubility of the polymer in a solvent, the coating property of a liquid crystal aligning agent, the degree of characteristics required for forming a liquid crystal alignment film such as alignment property of liquid crystal, voltage holding ratio, and accumulated charge, and may be one or two or more kinds of the same polymer.

If it shows Y₂Specific examples of (3) include: the structure of formula (2) described in claim 4 of International patent publication No. 2015/119168, and the structures of formulae (Y-1) to (Y-97) and (Y-101) to (Y-118) described in claims 8 to 12; a divalent organic group obtained by removing two amino groups from the formula (2) described in claim 6 of International patent publication No. 2013/008906; a divalent organic group obtained by removing two amino groups from the formula (1) described in claim 8 of International patent publication No. 2015/122413; international of international societyThe structure of formula (3) described in claim 8 of patent publication 2015/060360; a divalent organic group wherein two amino groups are removed from the formula (1) described in claim 8 of Japanese laid-open patent publication No. 2012-173514; divalent organic groups having two amino groups removed from the formulas (A) to (F) described in claim 9 of International publication No. 2010-050523, and the like.

Preferred Y is shown below₂The present invention is not limited to the structure of (1).

Among the above-mentioned structures, (B-28), (B-29), etc. are particularly preferable from the viewpoint of further improving the film strength, etc., and (B-1) to (B-3), etc. are particularly preferable from the viewpoint of further improving the liquid crystal alignment property, etc., and (B-14) to (B-18), etc. are particularly preferable from the viewpoint of further improving the relaxation rate of accumulated charges, etc., and (B-26), etc. are preferable from the viewpoint of further improving the voltage holding ratio, etc.

When the polyimide precursor containing the structural unit represented by formula (6) contains the structural unit represented by formula (7) at the same time, the structural unit represented by formula (6) is preferably 10 mol% or more, more preferably 15 mol% or more, and particularly preferably 20 mol% or more, based on the total of formula (6) and formula (7).

The molecular weight of the polyimide precursor used in the present invention is preferably 2000 to 500000, more preferably 5000 to 300000, and further preferably 10000 to 100000 in terms of weight average molecular weight.

Examples of the polyimide having a divalent group represented by the formula (1) in the main chain include polyimides obtained by ring-closing the above polyimide precursor. In this polyimide, the ring-closure ratio of the amic acid group (also referred to as imidization ratio) does not necessarily need to be 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 imidization by adding a catalyst to a solution of a polyimide precursor.

The liquid crystal aligning agent of the present invention is a composition containing the above-mentioned specific polymer and an organic solvent, and may contain two or more specific polymers having different structures. The liquid crystal aligning agent of the present invention may contain a polymer other than the specific polymer (hereinafter, also referred to as a second polymer) and various additives as long as the effects described in the present invention are exhibited.

When the liquid crystal aligning agent of the present invention contains the second polymer, the ratio of the specific polymer to the entire polymer components is preferably 5% by mass or more, and examples thereof include 5 to 95% by mass.

Examples of the second polymer 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.

In particular, a polyamic acid (hereinafter, also referred to as a second polyamic acid) obtained from a tetracarboxylic dianhydride component and a diamine component is preferable as the second polymer.

Examples of the tetracarboxylic dianhydride component for obtaining the second polyamic acid include compounds represented by the following formula (11). The acid dianhydride component may be composed of one compound or two or more compounds.

In the formula (11), A is a tetravalent organic group, preferably a tetravalent organic group having 4 to 30 carbon atoms.

Specific examples of A include preferable examples and X in the formula (6)₁Examples of (A) to (B)The structures shown are the same.

The diamine component for obtaining the second polyamic acid may be appropriately determined depending on the purpose, and for example, a diamine represented by the following formula (12) may be used.

(Y₉Represents a divalent organic group. A. the₉Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms, and may be the same or different. From the viewpoint of liquid crystal alignment properties, A₉Preferably a hydrogen atom or a methyl group. )

The following shows Y of formula (12) preferably used as a diamine component for obtaining a second polyamic acid₉The present invention is not limited to the structure of (1).

For the purpose of improving electrical characteristics and relaxation characteristics, Y₉Preferably a divalent organic group having a secondary or tertiary nitrogen atom, or a divalent organic group having-NH-CO-NH-in the molecule. At Y₉In the case of a divalent organic group having a second-or third-order nitrogen atom, specific examples of formula (12) include: the diamine having an azole structure described in international publication WO2017/126627 is preferably a diamine having a structure represented by the following formula (pr); the diamine having an azole structure described in international publication WO2018/062197 is preferably a diamine having a structure represented by the following formula (pn); the diamine having a carbazole structure described in international publication WO2018/110354 is preferably a diamine having a structure represented by the following formula (cz); international laid-open publication WO2015/046374 [0173 ]]～[0188]Diamine having a nitrogen-containing heterocycle as described in paragraph [0050 ] of Japanese patent laid-open publication No. 2016-218149]The diamine having a nitrogen-containing structure described in the paragraph, a diamine represented by the following formula (BP); 2, 3-diaminoPhenylpyridine, 2, 6-diaminopyridine, 3, 4-diaminopyridine, 2, 4-diaminopyrimidine, 5, 6-diamino-2, 3-dicyanopyrazine, 5, 6-diamino-2, 4-dihydroxypyrimidine, 2, 4-diamino-6-dimethylamino-1, 3, 5-triazine, 1, 4-bis (3-aminopropyl) piperazine, 4 '- [4, 4' -propane-1, 3-diylbis (piperidine-1, 4-diyl)]Diphenylamine, 2, 4-diamino-6-isopropoxy-1, 3, 5-triazine, 2, 4-diamino-6-methoxy-1, 3, 5-triazine, 2, 4-diamino-6-phenyl-1, 3, 5-triazine, 2, 4-diamino-6-methyl-1, 3, 5-triazine, 2, 4-diamino-1, 3, 5-triazine, 4, 6-diamino-2-vinyl-1, 3, 5-triazine, 3, 5-diamino-1, 2, 4-triazole, 6, 9-diamino-2-ethoxyacridine lactate, 3, 8-diamino-6-phenylphenanthridine, 1, 4-diaminopiperazine, 3, 6-diaminoacridine, bis (4-aminophenyl) -N-aniline, 4 '-diaminodiphenyl-N-methylamine, 4' -diaminodiphenylamine, 3, 6-diaminocarbazole, 2, 4-diamino-6-methoxy-1, 3, 5-triazine, 4-diamino-2-1, 3, 5-triazine, 4-diamino-1, 3, 5-triazine, 6-diamino-triazine, 9-methyl-3, 6-diaminocarbazole, 9-ethyl-3, 6-diaminocarbazole, diamines represented by the following formulae (w1) to (w2), and the like.

(R¹Represents a hydrogen atom, a fluorine atom, a cyano group, a hydroxyl group, a methyl group, R²Each independently represents a single bond or a group ". 1-R³－Ph－*2”，R³Represents a group selected from the group consisting of a single bond, -O-, -COO-, -OCO-, - (CH)₂)_l－、－O(CH₂)_mDivalent organic groups (l and m each represents an integer of 1 to 5) in O-, -CONH-, and-NHCO-, wherein 1 represents a site bonded to a benzene ring in the formula (pr), and 2 represents a site bonded to an amino group in the formula (pr). Ph represents a phenylene group. n represents 1 to 3. )

(R¹And R²Each independently represents a hydrogen atom or a methyl group, R³Represents a single bond or a group ". 1-R⁴－Ph－*2”，R⁴Represents a group selected from the group consisting of a single bond, -O-, -COO-, -OCO-, - (CH)₂)_l－、－O(CH₂)_mDivalent organic groups (l and m each represents an integer of 1 to 5) in O-, -CONH-, and-NHCO-, wherein 1 represents a site bonded to a benzene ring in the formula (pn), and 2 represents a site bonded to an amino group in the formula (pn). Ph represents a phenylene group. n represents 1 to 3. )

(R¹Represents a hydrogen atom or a methyl group, R²Represents a methyl group. )

(X is a biphenyl skeleton or a fluorene ring, Y is a group selected from a benzene ring, a biphenyl skeleton or-Ph-Z-Ph- (Ph represents phenylene), and Z is-O-, -NH-, -CH)₂－、－SO₂－、－C(CH₃)₂-or-C (CF)₃)₂-a divalent group as indicated. A and B are hydrogen atoms or methyl groups. )

(Sp represents phenylene, pyrrolidine, piperidine, piperazine, divalent chain hydrocarbon group having 2-20 carbon atoms, or-CH of the divalent chain hydrocarbon group₂A group substituted with a group selected from-O-, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group), -COS-, -NR- (R represents a methyl group), pyrrolidine, piperidine, and piperazine. )

At Y₉In the case of a divalent organic group having-NH-CO-NH-in the molecule, specific examples of the above formula (12) include diamines in the following cases: in the following formula (4), A₁is-NH-CO-NH-or-CH of alkylene with 2-20 carbon atoms₂At least one of-NH-CO-NH-substituted or-CH in C2-20 alkylene₂At least one of-is substituted by-NH-CO-NH-and the others are-CH₂At least one of the groups-CO-, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group), -COS-, -NR- (R represents a methyl group). Specific examples of more preferable diamines include diamines represented by the following formulas (U-1) to (U-9).

(A₁Represents a single bond, -NH-CO-NH-, or an alkylene group having 2 to 20 carbon atoms (wherein the alkylene group may be any-CH group₂-optionally substituted by-O-, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl-), -NRCOO- (R represents a hydrogen atom or a methyl-), -CONR- (R represents a hydrogen atom or a methyl-), -COS-, -NR- (R represents a methyl group) or-NH-CO-NH-. ). A. the₂Represents a halogen atom, a hydroxyl group, or an alkyl group or alkoxy group having 1 to 5 carbon atoms (wherein any hydrogen atom of the alkyl group or alkoxy group is optionally substituted by a halogen atom). a is an integer of 0 to 4, and A is an integer of 2 or more₂May be the same or different. b and c are each independently an integer of 1 to 2. )

Preferable specific examples of the diamines represented by the above formulae (w1) to (w2) include diamines represented by the following formulae (n 3-1) to (n 3-7), diamines represented by the following formulae (n 4-1) to (n 4-6), and the like.

For the purpose of improving printability, a diamine compound having a carboxyl group (COOH group) and a hydroxyl group (OH group) may also be used. Specific examples thereof include 2, 4-diaminophenol, 3, 5-diaminobenzyl alcohol, 2, 4-diaminobenzyl alcohol, 4, 6-diaminoresorcinol, 2, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid and 3, 5-diaminobenzoic acid. Among them, 2, 4-diaminobenzoic acid, 2, 5-diaminobenzoic acid, or 3, 5-diaminobenzoic acid is preferable. Further, diamine compounds represented by the following formulas [3 b-1 ] to [3 b-4 ] and diamine compounds in which the amino group is a secondary amino group can be used.

(formula [3 b-1 ]]In, Q¹Represents a single bond, -CH₂－、－C₂H₄－、－C(CH₃)₂－、－CF₂－、－C(CF₃)₂－、－O－、－CO－、－NH－、－N(CH₃)－、－CONH－、－NHCO－、－CH₂O－、－OCH₂－、－COO－、－OCO－、－CON(CH₃) -or-N (CH)₃)CO－，m¹And m²Each independently represents an integer of 0 to 4, and m¹+m²Represents an integer of 1 to 4, formula [3 b-2 ]]M in³And m⁴Each independently represents an integer of 1 to 5, formula [3 b-3]In, Q²Represents a linear or branched alkylene group having 1 to 5 carbon atoms, m⁵Represents an integer of 1 to 5, formula [3 b-4 ]]In, Q³And Q⁴Each independently represents a single bond, -CH₂－、－C₂H₄－、－C(CH₃)₂－、－CF₂－、－C(CF₃)₂－、－O－、－CO－、－NH－、－N(CH₃)－、－CONH－、－NHCO－、－CH₂O－、－OCH₂－、－COO－、－OCO－、－CON(CH₃) -or-N (CH)₃)CO－，m⁶Represents an integer of 1 to 4. )

The diamine component for obtaining the second polyamic acid may be a diamine used for a specific polymer or a known diamine other than the above-mentioned diamine component, but the present invention is not limited thereto. The diamine component for obtaining the second polyamic acid may be one kind of diamine, or two or more kinds of diamines may be used in combination.

< production methods of Polyamic acid, Polyamic acid ester and polyimide >

The polyamic acid ester, polyamic acid, and polyimide which are polyimide precursors used in the present invention can be synthesized by a known method described in, for example, international publication WO 2013/157586.

< liquid Crystal Aligning agent >

The liquid crystal aligning agent of the present invention contains a polymer (A). The liquid crystal aligning agent of the present invention may contain other polymers in addition to the polymer (a) and the desired second polymer. Examples of the other polymer include polyamic acids, polyimides, polyamic acid esters, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrenes or derivatives thereof, poly (styrene-phenylmaleimide) derivatives, and poly (meth) acrylates.

The liquid crystal aligning agent is used for producing a liquid crystal alignment film, and is preferably in the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal aligning agent of the present invention is preferably a coating solution containing the above-mentioned polymer component and an organic solvent. 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 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 it is a solvent in which the polymer component can be uniformly dissolved. Specific examples thereof include: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ -butyrolactone, 1, 3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide (these are also collectively referred to as "good solvents"), and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, or γ -butyrolactone is preferably used. The preferable solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the entire solvent contained in the liquid crystal aligning agent.

In addition to the above-mentioned solvents, the organic solvent contained in the liquid crystal aligning agent is preferably a mixed solvent in which a solvent (also referred to as a poor solvent) for improving coatability when the liquid crystal aligning agent is coated and surface smoothness of a coating film are used in combination. Specific examples of the organic solvent used in combination are as follows, but the organic solvent is not limited to these examples.

For example, there may be mentioned: diisopropyl ether, diisobutyl methanol (2, 6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1, 2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1- (2-butoxyethoxy) -2-propanol, 2- (2-butoxyethoxy) -1-propanol, propylene glycol mono-butyl ether, ethylene glycol mono-isoamyl ether, ethylene glycol mono-hexyl ether, propylene glycol mono-butyl ether, 1- (2-butoxyethoxy) -2-propanol, 2- (2-butoxyethoxy) -1-propanol, propylene glycol, Propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2, 6-dimethyl-4-heptanone), and the like.

Among them, diisobutylcarbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether acetate, diisobutyl ketone are preferably used.

Preferred combinations of the good solvent and the poor solvent include: n-methyl-2-pyrrolidone with ethylene glycol monobutyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, and ethylene glycol monobutyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, and propylene glycol monobutyl ether; n-ethyl-2-pyrrolidone with propylene glycol monobutyl ether; n-methyl-2-pyrrolidone, γ -butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and 2, 6-dimethyl-4-heptanone; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether; n-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and 2, 6-dimethyl-4-heptanol; n-methyl-2-pyrrolidone, gamma-butyrolactone, and dipropylene glycol dimethyl ether; n-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, and the like. The poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass of the entire solvent contained in the liquid crystal aligning agent. The kind and content of such a solvent are appropriately selected depending on the coating apparatus, coating conditions, coating environment, and the like of the liquid crystal aligning agent.

The liquid crystal aligning agent of the present invention may further contain a component other than the polymer component and the organic solvent. Examples of such additional components include: an adhesion promoter for improving adhesion between the liquid crystal alignment film and the substrate and adhesion between the liquid crystal alignment film and the sealing material, a compound for improving strength of the liquid crystal alignment film (hereinafter, also referred to as a crosslinkable compound), a dielectric for adjusting dielectric constant and resistance of the liquid crystal alignment film, a conductive substance, and the like.

As the crosslinkable compound, a compound having at least one group selected from the group consisting of an oxirane group (oxirane group), an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group having an oxazoline ring structure, a group having a Meldrum Acid (meidrum Acid) structure, a cyclocarbonate group, and a group represented by the following formula (d), or a compound selected from the group consisting of compounds represented by the following formula (e) (hereinafter, these are also collectively referred to as compound (C)), is preferable from the viewpoint of a small generation of AC afterimages and a high effect of improving the film strength.

(in the formula, R₇₁Is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or ". about. -CH₂－OH”，R₇₂And R₇₃Each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or ". about. -CH₂-OH ". Denotes a bond. A represents an (m + n) -valent organic group having an aromatic ring. m represents an integer of 1 to 6, and n represents an integer of 0 to 4. )

Specific examples of the compound having an oxirane group include: a compound having two or more oxirane groups, such as a compound described in paragraph [0037] of Japanese patent laid-open publication No. H10-338880 and a compound having a triazine ring in the skeleton described in International publication No. WO 2017/170483. Among them, nitrogen atom-containing compounds such as N, N, N ', N ', -tetraglycidyl m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N ', -tetraglycidyl-4, 4 ' -diaminodiphenylmethane, N, N, N ', N ' -tetraglycidyl p-phenylenediamine, and compounds represented by the following formulae (r-1) to (r-3) are particularly preferable.

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

Specific examples of the compound having a protected isocyanate group include: examples of the compound having two or more protected isocyanate groups include compounds having two or more protected isocyanate groups described in paragraphs [0046] to [0047] of Japanese patent application laid-open No. 2014-224978 and compounds having three or more protected isocyanate groups described in paragraphs [0119] to [0120] of International publication No. 2015/141598. Among them, preferred are compounds represented by the following formulae (bi-1) to (bi-3).

Specific examples of the compound having a protected isothiocyanate group include compounds having two or more protected isothiocyanate groups as described in Japanese patent application laid-open No. 2016-200798.

Specific examples of the compound having a group having an oxazoline ring structure include compounds having two or more oxazoline structures described in paragraph [0115] of Japanese patent application laid-open No. 2007-286597.

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

Specific examples of the compound having a cyclocarbonate group include compounds described in international publication No. WO 2011/155577.

As R in the above formula (d)₇₁、R₇₂、R₇₃Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group and a propyl group.

Specific examples of the compound having a group represented by the above formula (d) include compounds having two or more groups represented by the above formula (d) described in International publication No. WO2015/072554 and paragraph [0058] of Japanese patent application laid-open No. 2016-118753, and compounds described in Japanese patent application laid-open No. 2016-200798. Among them, preferred are compounds represented by the following formulae (hd-1) to (hd-8).

Examples of the (m + n) -valent organic group having an aromatic ring in a of the formula (e) include: a (m + n) -valent aromatic hydrocarbon group having 5 to 30 carbon atoms, a (m + n) -valent organic group in which the (m + n) -valent aromatic hydrocarbon group having 5 to 30 carbon atoms is bonded directly or via a linking group, and a (m + n) -valent group having an aromatic heterocyclic ring. Examples of the aromatic hydrocarbon group include benzene and naphthalene. Examples of the aromatic heterocyclic ring include: pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine ring, benzimidazole ring, indole ring, quinoxaline ring, acridine ring, etc. Examples of the linking group include: an alkylene group having 1 to 10 carbon atoms, a group obtained by removing one hydrogen atom from the alkylene group, a divalent or trivalent cyclohexane ring, or the like. Any hydrogen atom of the alkylene group is optionally substituted with an organic group such as a fluorine atom or a trifluoromethyl group. Specific examples thereof include compounds described in international publication No. WO 2010/074269. Preferable specific examples thereof include the following formulas (e-1) to (e-9).

The compound is an example of a crosslinkable compound, and is not limited thereto. For example, components other than those described above disclosed on pages 53 to 55 of International patent publication No. 2015/060357 can be mentioned. The liquid crystal aligning agent of the present invention may contain one kind of crosslinkable compound, or two or more kinds of crosslinkable compounds may be combined.

The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, and more preferably 1 to 15 parts by mass from the viewpoint of the progress of the crosslinking reaction, the achievement of the desired effect, and the reduction of the generation of AC afterimages.

Examples of the adhesion promoter include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, 4, 7-triazadecane, 10-triethoxysilyl-1, 4, 7-triazadecane, 9-trimethoxysilyl-3, 6-diazainonyl acetate, 9-triethoxysilyl-3, 6-diazainonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 9-glycidoxypropylmethyldiethoxysilane, N-propyltrimethoxysilane, N-ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N-propyltrimethoxysilane, N-ethyltrimethoxysilane, N-propyltrimethoxysilane, N-ethyltriethoxysilane, N-propyltrimethoxysilane, N-butyltrimethoxysilane, N-N, Silane coupling agents such as 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris (trimethoxysilylpropyl) isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane. When these silane coupling agents are used, from the viewpoint of reducing the generation of AC afterimages, the amount of the silane coupling agent is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

< liquid crystal alignment film/liquid crystal display element >

The liquid crystal alignment film can be produced by using the liquid crystal aligning agent. The liquid crystal display element of the present invention further includes a liquid crystal alignment film formed using the liquid crystal aligning agent. The operation mode of the liquid crystal display element of the present invention is not particularly limited, and the liquid crystal display element can be applied to various operation modes such as tn (twisted nematic) mode, STN mode, vertical alignment mode (including VA-MVA mode, VA-PVA mode, and the like), in-plane switching mode (IPS mode), ffs (fringe Field switching) mode, and Optically Compensated bend mode (OCB mode: Optically Compensated Birefringence mode).

The liquid crystal display element of the present invention can be manufactured, for example, by a process including the following steps (1-1) to (1-3). In the step (1-1), the substrate is used differently depending on the desired operation mode. The operation modes of the step (1-2) and the step (1-3) are common.

[ Process (1-1): formation of coating film ]

First, the liquid crystal aligning agent of the present invention is applied to a substrate, and then the coated surface is heated, thereby forming a coating film on the substrate.

(1－1A)

For example, in the case of manufacturing a TN-type, STN-type, or VA-type liquid crystal display element, first, two substrates provided with a patterned transparent conductive film are paired, and the liquid crystal alignment agent prepared in the above-described manner is applied to each transparent conductive film formation surface by, preferably, an offset printing method, a spin coating method, a roll coater, or an inkjet printing method. As the substrate, for example, a glass such as float glass (float glass) or soda glass (soda glass); and transparent substrates made of plastics such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (alicyclic olefin). As the transparent conductive film provided on one surface of the substrate, tin oxide (SnO) can be used₂) The NESA film (registered trademark of PPG corporation, USA) is composed of indium oxide-tin oxide (In)₂O₃－SnO₂) And an ITO film formed therefrom. In order to obtain a patterned transparent conductive film, for example, the following method can be used: a method of forming a pattern by photolithography after forming a transparent conductive film without a pattern; a method of using a mask having a desired pattern when forming a transparent conductive film; and the like. In the case of applying the liquid crystal aligning agent, a pretreatment of applying a functional silane compound, a functional titanium compound or the like to the surface of the substrate in advance on which the coating film is formed may be performed in order to improve the adhesion between the substrate surface and the transparent conductive film and the coating film.

After the liquid crystal aligning agent is applied, it is preferable to perform preliminary heating (prebaking) for the purpose of preventing the liquid of the applied liquid crystal aligning agent from sagging. The pre-drying temperature is preferably 30-200 ℃, more preferably 40-150 ℃, and particularly preferably 40-100 ℃. The pre-drying time is preferably 0.25 to 10 minutes, and more preferably 0.5 to 5 minutes. Thereafter, the solvent is completely removed, and a firing (postbaking) step is performed, if necessary, for the purpose of thermally imidizing the amic acid structure present in the polymer. The firing temperature (post-baking temperature) at this time is preferably 80 to 300 ℃, more preferably 120 to 250 ℃. The post-baking time is preferably 5 to 200 minutes, and more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5. mu.m.

(1－1B)

In the case of manufacturing an IPS-type or FFS-type liquid crystal display element, a liquid crystal aligning agent is applied to an electrode forming surface of a substrate provided with electrodes formed of a transparent conductive film or a metal film patterned into a comb-tooth shape and a surface of an opposing substrate not provided with the electrodes, and then the respective applied surfaces are heated to form a coating film. The preferable film thickness of the substrate and the transparent conductive film used in this case, the coating method, the heating condition after coating, the method for patterning the transparent conductive film or the metal film, the pretreatment of the substrate, and the formed coating film is the same as in (1-1A) above. As the metal film, for example, a film made of metal such as chromium can be used.

In both cases (1-1A) and (1-1B), the liquid crystal alignment film or the coating film to be the liquid crystal alignment film is formed by applying the liquid crystal alignment agent to the substrate and then removing the organic solvent. In this case, the polyamic acid, polyamic acid ester, and polyimide blended with the liquid crystal aligning agent of the present invention may be subjected to a dehydration ring-closure reaction by further heating after the formation of the coating film, thereby forming a further imidized coating film.

[ Process (1-2): orientation ability imparting treatment

In the case of producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal display element, the coating film formed in the above-described step (1-1) is subjected to a treatment for imparting liquid crystal aligning ability. This imparts the alignment ability of the liquid crystal molecules to the coating film, thereby forming a liquid crystal alignment film. Examples of the orientation ability imparting treatment include: a brush-polishing process of rubbing a coating film in a certain direction by a roll obtained by winding a cloth made of fibers such as nylon, rayon, and cotton; and photo-alignment treatment in which the coating film is irradiated with polarized or unpolarized radiation. On the other hand, in the case of producing a VA liquid crystal display device, the coating film formed in the step (1-1) may be used as it is as a liquid crystal alignment film, or the coating film may be subjected to an alignment ability imparting treatment.

When the liquid crystal aligning ability is imparted to the coating film by the photo-alignment treatment, for example, ultraviolet rays and visible rays including light having a wavelength of 150 to 800nm can be used as the radiation to be irradiated to the coating film. When the radiation is polarized, the radiation may be linearly polarized or partially polarized. When the radiation to be used is linearly polarized or partially polarized, the irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination thereof. When unpolarized radiation is irradiated, the irradiation direction is an oblique direction.

Examples of the light source that can be used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and an excimer laser (excimer laser). Ultraviolet rays in a preferred wavelength range can be obtained by a method of using a light source in combination with, for example, a filter, a diffraction grating, or the like. The irradiation dose of the radiation is preferably 10 to 5000mJ/cm²More preferably 30 to 2000mJ/cm²。

In addition, in order to improve the reactivity, the light irradiation of the coating film may be performed while heating the coating film. The temperature during heating is usually 30 to 250 ℃, preferably 40 to 200 ℃, and more preferably 50 to 150 ℃.

In the case of using ultraviolet rays containing light having a wavelength of 150 to 800nm, the light-irradiated film obtained in the above-described step may be used as it is as a liquid crystal alignment film, or the light-irradiated film may be subjected to firing, washing with water or an organic solvent, or a combination thereof. The firing temperature at this time is preferably 80 to 300 ℃, more preferably 80 to 250 ℃. The firing time is preferably 5 to 200 minutes, and more preferably 10 to 100 minutes. The number of firing may be once or two or more. The photo-alignment treatment herein corresponds to a treatment of light irradiation in a state of not being in contact with the liquid crystal layer.

The organic solvent used for the above washing is not particularly limited, and specific examples thereof include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, or the like.

The liquid crystal alignment film after the rubbing treatment may be further subjected to a treatment for imparting different liquid crystal alignment ability to each region of the liquid crystal alignment film, the treatment comprising: a process of changing the pretilt angle of a region of a part of the liquid crystal alignment film by irradiating the part of the liquid crystal alignment film with ultraviolet rays; after a protective (rasist) film is formed on a part of the surface of the liquid crystal alignment film, a rubbing treatment is performed in a direction different from the previous rubbing treatment, and then the protective film is removed. In this case, the viewing characteristics of the resulting liquid crystal display element can be improved. The liquid crystal alignment film preferable for the VA-type liquid crystal display element can also be preferably used for a psa (polymer sustained alignment) -type liquid crystal display element.

[ Process (1-3): construction of liquid Crystal cell

(1－3A)

As described above, two substrates on which liquid crystal alignment films are formed are prepared, and liquid crystal is disposed between the two substrates disposed to face each other, thereby manufacturing a liquid crystal cell. For manufacturing a liquid crystal cell, the following two methods can be cited, for example. The first method is a conventionally known method. First, two substrates are arranged to face each other with a gap (cell gap) therebetween so that the liquid crystal alignment films face each other, the peripheral portions of the two substrates are bonded to each other with a sealant, a liquid crystal is injected into the cell gap defined by the substrate surfaces and the sealant and filled in the cell gap, and then the injection hole is sealed, thereby manufacturing a liquid crystal cell. The second method is a method called an ODF (One Drop Fill) method. For example, a uv-curable sealant is applied to a predetermined position on one of two substrates on which a liquid crystal alignment film is formed, liquid crystal is dropped onto predetermined portions on the surface of the liquid crystal alignment film, the other substrate is bonded to the liquid crystal alignment film so as to face each other, the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with uv light to cure the sealant, thereby producing a liquid crystal cell. In either case, it is desirable that the liquid crystal cell manufactured as described above be further heated to a temperature at which the liquid crystal becomes isotropic, and then slowly cooled to room temperature, thereby removing the flow alignment during filling of the liquid crystal.

As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

Examples of the liquid crystal include: the nematic liquid crystal is preferably a schiff base (schiff base) liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a diphenylcyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, a bicyclooctane liquid crystal, a cubane (cubane) liquid crystal, or the like. In addition, cholesteric liquid crystals such as cholesteric liquid crystals using, for example, chlorinated cholesterol, cholesteryl nonanoate, cholesteryl carbonate, or the like; chiral agents sold under the trade names "C-15" and "CB-15" (manufactured by MERCK corporation); ferroelectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate and the like. In addition, the liquid crystal may additionally contain an anisotropic dye. The term "dye" refers to a substance capable of absorbing or deforming light in at least a part or the entire range intensively in a visible light region, for example, in a wavelength range of 400nm or 700nm, and the term "anisotropic dye" refers to a substance capable of absorbing light anisotropically in at least a part or the entire range of the visible light region.

The color tone of the liquid crystal cell can be adjusted by using the above-mentioned dye. The kind of the anisotropic dye is not particularly limited, and for example, a black dye (black dye) or a color dye (color dye) may be used. The ratio of the anisotropic dye to the liquid crystal can be appropriately selected within a range in which the physical properties are not impaired, and for example, the anisotropic dye can be contained in a ratio of 0.01 to 5 parts by weight with respect to 100 parts by weight of the liquid crystal compound, and the ratio can be changed within an appropriate range as needed.

(1－3B)

When a PSA liquid crystal display device is manufactured, a liquid crystal cell is constructed in the same manner as in (1-3A) above, except that a photopolymerizable compound such as the following formulae (w-1) to (w-5) is injected or dropped together with the liquid crystal.

Then, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. The voltage applied here may be, for example, 5 to 50V DC or AC. The light to be irradiated may be, for example, ultraviolet light and visible light including light having a wavelength of 150 to 800nm, but ultraviolet light including light having a wavelength of 300 to 400nm is preferable. As a light source for irradiating light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The ultraviolet light in the above-described preferred wavelength range can be obtained by a method of using a light source in combination with, for example, a filter, a diffraction grating, or the like. The dose of light irradiation is preferably 100mJ/cm²Above and less than 30000mJ/cm²More preferably 100 to 20000mJ/cm²。

(1－3C)

When a coating film is formed on a substrate using a liquid crystal aligning agent containing a compound having a photopolymerizable group (a polymer or an additive), a liquid crystal cell is constructed in the same manner as in (1-3A), and thereafter, the following method may be employed: a method for manufacturing a liquid crystal display element includes a step of irradiating a liquid crystal cell with light while applying a voltage between conductive films of a pair of substrates. According to this method, the advantage of the PSA mode can be achieved with a small amount of light irradiation. Light irradiation to the liquid crystal cell may be performed in a state where a voltage is applied to drive the liquid crystal, or may be performed in a state where a low voltage is applied to the extent that the liquid crystal is not driven. The applied voltage may be, for example, 0.1 to 30V DC or AC. The above (1-3B) can be applied to the conditions of the light to be irradiated. The light irradiation treatment here corresponds to a treatment of light irradiation in a state of being in contact with the liquid crystal layer.

The liquid crystal display element of the present invention can be obtained by bonding a polarizing plate to the outer surface of the liquid crystal cell. Examples of the polarizing plate attached to the outer surface of the liquid crystal cell include: a polarizing plate which is formed by sandwiching a polarizing film called "H film" which absorbs iodine while extending and orienting polyvinyl alcohol with a cellulose acetate protective film; or a polarizing plate composed of the H film itself.

The liquid crystal display element of the present invention can be effectively used in various devices, for example, various display devices such as a clock, a portable game machine, a word processor (word processor), a notebook computer, a car navigation system, a camcorder (camcorder), a PDA (Personal Digital Assistant), a Digital camera, a mobile phone, a smart phone, various monitors, a liquid crystal television, an information display, and the like.

As described above, by using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film which is less likely to cause image sticking and which can minimize bright spots even when physical rubbing such as rubbing due to spacers occurs, and a liquid crystal display element including the liquid crystal alignment film can be obtained. In addition, the resulting liquid crystal display element has high reliability.

Examples

The present invention will be described in further detail with reference to the following examples, but the present invention is not limited thereto. The abbreviations for the compounds used are as follows.

(liquid Crystal)

MLC-3019 (positive liquid crystal, manufactured by MERCK corporation).

(diamine Compound)

WA-1: a compound represented by the formula [ WA-1 ].

WA-2: a compound represented by the formula [ WA-2 ].

(other diamine Compound)

A1-A7: are compounds represented by the formulae [ A1] to [ A7 ].

(Boc represents a tert-butoxycarbonyl group.)

(acid dianhydride Compound)

B1-B3: are compounds represented by the formulae [ B1] to [ B3 ].

(solvent)

NMP: n-methyl-2-pyrrolidone.

BCS: ethylene glycol monobutyl ether.

GBL: gamma-butyrolactone.

(additives)

S-1: 3-glycidoxypropyltriethoxysilane.

(crosslinking agent)

AD-1: a compound represented by the following formula (AD-1).

(measurement of molecular weight)

The molecular weights of the polyimide precursor and the polyimide were measured as described below using a Gel Permeation Chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko K.K.) and a column (KD-803, KD-805) (manufactured by Shodex K.K.).

Temperature of the column: at 50 ℃.

Eluent: n, N-dimethylformamide (as additive, lithium bromide monohydrate (LiBr. H)₂O) is 30mmol/L (liter), 30mmol/L phosphoric acid/anhydrous crystalline (o-phosphoric acid), 10mL/L Tetrahydrofuran (THF).

Flow rate: 1.0 mL/min.

Calibration curve preparation standard sample: TSK-standard polyethylene oxides (molecular weights: about 900000, 150000, 100000 and 30000, manufactured by Tosoh corporation) and polyethylene glycols (molecular weights: about 12000, 4000 and 1000, manufactured by Polymer Laboratory corporation).

(measurement of imidization ratio of polyimide)

To an NMR (nuclear magnetic resonance) sample tube (. phi.5, manufactured by Softweed scientific Co., Ltd.), 20mg of polyimide powder was added, and deuterated dimethyl sulfoxide (DMSO-d 6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53mL) was added and ultrasonic waves were applied to completely dissolve the polyimide powder. The proton NMR of the solution at 500MHz was measured by an NMR spectrometer (JNW-ECA 500) (manufactured by electronic DATUM, Japan). The imidization ratio was determined as follows: the proton derived from a structure which does not change before and after imidization is determined as a reference proton, and the peak integral value of the proton derived from an NH group of amic acid present in the vicinity of 9.5 to 10.0ppm are used to obtain the proton from the following formula.

Imidization ratio (%) - (1-. alpha.x/y). times.100

In the above formula, x is a peak integral value of a proton derived from an NH group of amic acid, y is a peak integral value of a reference proton, and α is a ratio of the number of reference protons to the number of protons of one NH group of amic acid in the case of polyamic acid (imidization ratio of 0%).

(measurement of viscosity)

In the synthetic examples or comparative synthetic examples, the viscosity of the polyimide polymer was measured using an E-type viscometer TVE-22H (manufactured by Toyobo Co., Ltd.) at a sample volume of 1.1mL, a conical rotor TE-1 (1 ℃ C., 34', R24) and a temperature of 25 ℃.

(WA-1) the synthesis WAs carried out with reference to the following prior art documents.

Salvatore Zarra,Jack K.Clegg,Jonathan R.Nitschke,Angewandte Chemie International Edition,52,18,(4837－4840,Supporting Information:S2－S3),(2013).

(WA-2) is a novel compound not disclosed in the literature and the like, and the synthesis method is described in detail below.

The product passage described in synthetic example 1 below¹H-NMR analysis was carried out for identification (analysis conditions are as follows).

The device comprises the following steps: BRUKER ADVANCE III-500 MHz.

And (3) determination of a solvent: DMSO-d₆。

Reference substance: tetramethylsilane (TMS) (delta 0.0ppm for¹H)。

The abbreviations in the present invention have the following meanings.

THF: tetrahydrofuran.

DCE: 1, 2-dichloroethane.

DMAP: n, N-dimethyl-4-aminopyridine.

< Synthesis of monomer example 1 WA-2 >

< Synthesis of Compound [1]

To 1, 2-dichloroethane (540g), added were (4, 4 ' -dinitro- [1, 1 ' -biphenyl ] -2, 2 ' -diyl) dimethanol (60.0g, 0.197mol), triethylamine (45.9g, 0.454mol), and N, N-dimethyl-4-aminopyridine (2.39g, 0.0197mol), and stirred under ice-cooling conditions. Di-tert-butyl dicarbonate (94.7g, 0.434mol) diluted with 1, 2-dichloroethane (60g) was added dropwise with paying attention to heat generation, and after no heat generation, the mixture was stirred at room temperature overnight. After completion of the reaction, stirring was stopped, water (600g) was added for liquid separation and washing, and liquid separation and extraction were performed with chloroform (300g × 2 times). The organic phase was concentrated, and the obtained crude product was purified by silica gel column chromatography using a mixed solvent of ethyl acetate/hexane 2/1 (volume ratio), and the obtained solution was concentrated and dried to obtain a crude product of compound [1] (yield: 102 g). The obtained compound was used directly in the next step.

¹H－NMR(500MHz)in DMSO－d₆：8.41ppm(s，2H)，8.33ppm(d，2H，J＝8.5Hz)，7.58ppm(d，2H，J＝8.5Hz)，4.90ppm(s，4H)，1.39ppm(s，18H).

< Synthesis of WA-2 >

The crude compound [1] (101g) and 3% platinum carbon (aqueous product) (8.00g) were put into tetrahydrofuran (600g), and the mixture was stirred overnight at room temperature under a hydrogen atmosphere. After completion of the reaction, platinum carbon was removed by filtration, and the reaction mixture was concentrated under reduced pressure. Methanol WAs added to the crude product to concentrate again, followed by drying, whereby WA-2 (yield: 86.6g, 0.195mol) WAs obtained.

¹H－NMR(500MHz)in DMSO－d₆：6.72ppm(d，2H，J＝8.0Hz)，6.63ppm(d，2H，J＝2.5Hz)，6.52ppm(d，1H，J＝2.5Hz)，6.50ppm(d，1H，J＝2.0Hz)，5.15ppm(s，4H)，4.64－4.59ppm(m，4H)，1.34ppm(s，18H).

(Synthesis example 1)

WA-1 (2.19g, 9.00mmol), A1(1.83g, 7.50mmol), A2(1.72g, 7.50mmol), A4(2.04g, 6.00mmol) and B2(1.12g, 4.50mmol) were mixed with NMP (50.6g) and reacted at 50 ℃ for 3 hours, then B1(5.32g, 23.7mmol) and NMP (30.1g) were added and reacted at 40 ℃ for 15 hours to obtain a polyamic acid solution [1] (viscosity 384 mPas) having a resin solid content concentration of 15 mass%.

To the obtained polyamic acid solution [1] (30.0g) was added NMP, and the mixture was diluted to 10.0 mass%, and then acetic anhydride (4.83g) and pyridine (1.50g) as imidization catalysts were added to conduct a reaction at 55 ℃ for 2.5 hours. The reaction solution was poured into methanol (280mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ℃ to obtain polyimide powder (1). The polyimide had an imidization rate of 78.1%, a number average molecular weight of 12322 and a weight average molecular weight of 44438.

(Synthesis example 2)

WA-2 (4.00g, 9.00mmol), A1(1.83g, 7.50mmol), A2(1.72g, 7.50mmol), A4(2.04g, 6.00mmol) and B2(1.12g, 4.50mmol) were mixed with NMP (50.6g) and reacted at 50 ℃ for 3 hours, then B1(5.32g, 23.7mmol) and NMP (30.1g) were added and reacted at 40 ℃ for 15 hours to obtain a polyamic acid solution [2] having a resin solid content concentration of 15 mass% (viscosity 188 mPas).

To the obtained polyamic acid solution [2] (30.0g) was added NMP, and the mixture was diluted to 10.0 mass%, and acetic anhydride (4.83g) and pyridine (1.50g) as imidization catalysts were added and reacted at 55 ℃ for 2.5 hours. The reaction solution was poured into methanol (280mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ℃ to obtain polyimide powder (2). The polyimide had an imidization rate of 80.1%, a number average molecular weight of 10582 and a weight average molecular weight of 41856.

(Synthesis example 3)

A6(1.19g, 6.00mmol), A7(4.78g, 24.0mmol) and B2(3.75g, 15.0mmol) were mixed with NMP (55.1g) and reacted at 50 ℃ for 3 hours, then B3(4.06g, 13.8mmol) and NMP (23.0g) were added and reacted at 70 ℃ for 15 hours to obtain a polyamic acid solution [3] having a resin solid content of 15 mass% (viscosity 941 mPas).

The polyamic acid solution [3] had a number average molecular weight of 15244 and a weight average molecular weight of 40724.

(comparative Synthesis example 1)

A5(1.91g, 9.00mmol), A1(1.83g, 7.50mmol), A2(1.72g, 7.50mmol), A4(2.04g, 6.00mmol) and B2(1.12g, 4.50mmol) were mixed with NMP (50.6g) and reacted at 50 ℃ for 3 hours, then B1(5.32g, 23.7mmol) and NMP (30.1g) were added and reacted at 40 ℃ for 15 hours to obtain a polyamic acid solution [ R1] (viscosity 365 mPas) having a resin solid content concentration of 15 mass%.

To the obtained polyamic acid solution [ R1] (30.0g) was added NMP, and the mixture was diluted to 10.0 mass%, and acetic anhydride (4.83g) and pyridine (1.50g) were added as an imidization catalyst, followed by reaction at 55 ℃ for 2.5 hours. The reaction solution was poured into methanol (280mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ℃ to obtain a polyimide powder (R1). The polyimide had an imidization rate of 76.1%, a number average molecular weight of 10958, and a weight average molecular weight of 39958.

< preparation of liquid Crystal Aligning agent >

Examples of the preparation of the liquid crystal aligning agent are described in examples and comparative examples. The liquid crystal aligning agents obtained in examples and comparative examples were used to fabricate liquid crystal display elements and to conduct various evaluations.

(example 1)

NMP (22.0g) was added to the polyimide powder (1) (3.00g) obtained in Synthesis example 1, and the mixture was stirred at 80 ℃ for 15 hours to dissolve the powder. To this solution (2.75g), polyamic acid solution [3] (3.30g) obtained in Synthesis example 3, NMP (1.35g), GBL (3.675g), BCS (3.00g), NMP10 mass% diluted solution of AD-1 (0.248g), and GBL1 mass% diluted solution of S-1 (0.825g) were added and stirred at room temperature for 5 hours to obtain a liquid crystal aligning agent (V-1). In this liquid crystal aligning agent, no abnormality such as clouding, precipitation, etc. was observed, and it was confirmed that the solution was a uniform solution.

(example 2)

A liquid crystal aligning agent (V-2) was obtained in the same manner as in example 1, except that the polyimide powder (2) was used instead of the polyimide powder (1) in example 1. In this liquid crystal aligning agent, no abnormality such as clouding, precipitation, etc. was observed, and it was confirmed that the solution was a uniform solution.

Comparative example 1

A liquid crystal aligning agent (W-1) was obtained in the same manner as in example 1, except that the polyimide powder (R1) was used in place of the polyimide powder (1) in example 1. In this liquid crystal aligning agent, no abnormality such as clouding, precipitation, etc. was observed, and it was confirmed that the solution was a uniform solution.

< preparation of sample for evaluation of sealing adhesion >

Adhesion evaluation samples were prepared as follows. The liquid crystal alignment agents (V-1) and (V-2) obtained in examples and the liquid crystal alignment agent (W-1) obtained in comparative example were applied to an ITO substrate of 30 mm. times.40 mm by spin coating. After drying on a hot plate at 80 ℃ for 120 seconds, the film was baked in a hot air circulation oven at 230 ℃ for 20 minutes to form a coating film having a film thickness of 100nm, thereby obtaining a substrate with a liquid crystal alignment film.

Two substrates thus obtained were prepared, and a bead-like spacer having a diameter of 4 μm was applied to the liquid crystal alignment film surface of one of the substrates, followed by dropwise addition of a sealing agent (XN-1500T, manufactured by Co., Ltd.). Next, the other substrate was bonded so that the liquid crystal alignment film surface was on the inner side and the overlapping width of the periphery of the substrates was 1cm each. At this time, the dropping amount of the sealant was adjusted so that the diameter of the sealant after bonding was 3 mm. After fixing the two bonded substrates with a jig, the substrates were irradiated with 3J light of 365nm and thermally cured at 120 ℃ for 1 hour to prepare a sample for evaluating adhesion.

< evaluation of adhesion >

Then, the sample substrate obtained above was pressed from above the central portion of the substrate after the end portions of the upper and lower substrates were fixed by a table type precision universal testing machine AGS-X500N manufactured by shimadzu corporation, and the force (N) at the time of peeling was measured. The case where (N) is less than 3.50 is defined as "poor", and the case where (N) is 3.50 or more is defined as "good". The results are shown in Table 1.

< evaluation of film Strength (film hardness) >

The liquid crystal aligning agent is coated on the ITO surface of the glass substrate with the ITO electrode on the whole surface by spin coating. After drying on a hot plate at 80 ℃ for 2 minutes, a coating film having a thickness of 100nm was formed. The film was coated on the surface to be 150mJ/cm²The method (3) is performed by irradiating polarized ultraviolet rays. Then, the substrate was fired at 230 ℃ for 30 minutes in an IR oven to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film was rubbed with rayon cloth (roll diameter: 120mm, roll rotation speed: 1000rpm, moving speed: 20mm/sec, pressing length: 0.6 mm). The substrate was measured by using a HZ-V3 haze meter manufactured by SUGA TESTER CORPORATION. The evaluation was made by defining the case where the haze value was 0.3 or more as "poor", and the case where the haze value was less than 0.3 as "good". The results are shown in Table 1.

< production of liquid Crystal cell for evaluating liquid Crystal orientation >

Hereinafter, a method for manufacturing a liquid crystal cell for evaluating liquid crystal alignment properties is described.

A liquid crystal cell having a configuration of an FFS type liquid crystal display element was produced. First, a substrate with electrodes is prepared. The substrate is a glass substrate with the size of 30mm multiplied by 35mm and the thickness of 0.7 mm. An IZO electrode constituting a counter electrode is formed on the entire surface of the substrate as a first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by a CVD method is formed as a second layer. The SiN film of the second layer has a film thickness of 500nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film is disposed as a third layer, and two kinds of pixels, i.e., a first pixel and a second pixel, are formed. The size of each pixel is 10mm long and about 5mm wide. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the SiN film of the second layer.

The pixel electrode in the third layer has a comb-tooth shape in which a plurality of < symbol-shaped electrode elements each having a central portion bent are arranged, as in the drawings described in japanese patent application laid-open No. 2014-77845 (japanese laid-open patent publication). The width of each electrode element in the short dimension direction was 3 μm, and the interval between the electrode elements was 6 μm. Since the pixel electrode forming each pixel is configured such that a plurality of electrode elements having a < symbol shape whose central portion is bent are arranged, each pixel has a shape similar to a bold < symbol, which is bent at the central portion in the same manner as the electrode elements, instead of being rectangular. Each pixel is divided vertically at a central bent portion into a boundary, and has a first region above the bent portion and a second region below the bent portion.

The first region and the second region of each pixel are compared, and the formation directions of the electrode elements constituting the pixel electrodes are different. That is, when the direction of a line segment projecting the polarization plane of polarized ultraviolet rays, which will be described later, on the substrate is taken as a reference, the electrode element of the pixel electrode is formed so as to be at an angle of +80 ° (clockwise) in the first region of the pixel, and the electrode element of the pixel electrode is formed so as to be at an angle of-80 ° (clockwise) in the second region of the pixel. That is, in the first region and the second region of each pixel, the directions of the in-plane switching (in-plane switching) of the liquid crystal in the substrate plane induced by the voltage application between the pixel electrode and the counter electrode are configured to be opposite to each other.

Next, the liquid crystal aligning agents obtained in the synthesis examples and comparative synthesis examples were filtered through a 1.0 μm filter, and then applied to the prepared electrode-attached substrate by spin coating. Next, the plate was dried on a hot plate set at 80 ℃ for 120 seconds. Next, using an exposure apparatus manufactured by USHIO motors: APL-L050121S 1S-APW 01, wherein the substrate is irradiated with the linear polarization of the ultraviolet light from the vertical direction through the wavelength selective filter and the polarizing plate. At this time, the polarization plane direction is set as follows: the direction of the line segment projecting the polarization plane of the polarized ultraviolet rays onto the substrate is a direction inclined by 80 ° with respect to the third layer of IZO comb electrodes. Next, the substrate was baked in an IR (infrared) type oven at 230 ℃ for 30 minutes to obtain a substrate with a polyimide liquid crystal alignment film having a film thickness of 100nm, which had been subjected to alignment treatment. Further, as the counter substrate, a substrate with a polyimide liquid crystal alignment film was obtained by subjecting a glass substrate having a column spacer with a height of 4 μm, on the back surface of which an ITO electrode was formed, to an alignment treatment in the same manner as described above. The two substrates with the liquid crystal alignment films were set as a set, and a sealant was printed in a form in which a liquid crystal injection port was left on one substrate, and the other substrate was bonded and pressure-bonded so that the liquid crystal alignment films were opposed to each other and the direction of the line segment projecting the polarization plane of the polarized ultraviolet ray to the substrate was parallel. Then, the sealant was cured to produce an empty cell having a cell gap of 4 μm. Liquid crystal MLC-3019 (positive liquid crystal manufactured by MERCK) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed, thereby obtaining an FFS type liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 ℃ for 30 minutes and placed at 23 ℃ after evening, for evaluation of liquid crystal alignment.

< evaluation of liquid Crystal alignment >

With this liquid crystal cell, the case where flow alignment could be confirmed was defined as "poor", and the case where flow alignment could not be confirmed was defined as "good". The results are shown in Table 1.

[ Table 1]

From the above results, it WAs found that in the evaluation of adhesion, the liquid crystal alignment films obtained from the liquid crystal alignment agents using the diamine compounds WA-1 and WA-2 exhibited higher adhesion than the liquid crystal alignment film obtained from the liquid crystal alignment agent using the diamine compound A5. Specifically, the results are shown in Table 1 for comparison between examples 1 to 2 and comparative example 1.

Further, in the evaluation of the film strength, it was found that: the liquid crystal alignment films obtained from the liquid crystal alignment agents using the diamine compounds WA-1 and WA-2 exhibited higher film strength than the liquid crystal alignment films obtained from the liquid crystal alignment agent using the diamine compound A5. Specifically, the results are shown in Table 1 for comparison between examples 1 to 2 and comparative example 1.

Further, it is known that: the liquid crystal alignment films obtained from the liquid crystal alignment agents using the diamine compounds WA-1 and WA-2 exhibited equivalent liquid crystal alignment properties to those of the liquid crystal alignment films obtained from the liquid crystal alignment agent using the diamine compound A5.

According to the above, when WA-1 and WA-2 having biphenyl skeletons and having specific side chains are used, the seal adhesion and film strength can be improved while maintaining the liquid crystal alignment.

Industrial applicability

A liquid crystal display element using a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention can be preferably used for a liquid crystal display element. These elements are useful for liquid crystal displays for display purposes, and are also useful for light control windows, optical shutters (optical shutters), and the like that control light transmission and blocking.