CN109564368B

CN109564368B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN109564368B
Application number: CN201780048805.5A
Authority: CN
Inventors: 巴幸司; 森本佳道; 石井秀则
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2016-08-10
Filing date: 2017-08-09
Publication date: 2021-11-05
Anticipated expiration: 2037-08-09
Also published as: KR102408293B1; JPWO2018030489A1; TW201821600A; CN109564368A; WO2018030489A1; KR20190031583A; JP7107220B2; TW202407083A

Abstract

Provided are a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element, which can obtain a liquid crystal alignment film having excellent voltage holding ratio, fast relaxation of accumulated charges, and less flickering during driving. The liquid crystal aligning agent comprises a polymer (A) having a structure represented by formula (1) and a polymer (B) having a structure represented by formula (2). R¹Represents hydrogen or C1-3 alkyl, in formula (2), R²Is a single bond or a 2-valent organic radical, R³Is- (CH)₂)_n-a structure represented by (wherein n is an integer of 2 to 20, optionally-CH)₂-optionally substituted, in the absence of mutual adjacency, by a bond selected from the group consisting of ether, ester, amide, urea and carbamate, the hydrogen atoms of the amide and urea being optionally substituted by methyl or tert-butoxycarbonyl. ) R⁴Is a single bond or a 2-valent organic group, any hydrogen atom on the phenyl ring being optionally substituted with a 1-valent organic group.

Description

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

Technical Field

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

Background

Liquid crystal display elements are widely used as display portions of computers, mobile phones, smart phones, televisions, and the like. The liquid crystal display element includes, for example, a liquid crystal layer interposed between an element substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls alignment of liquid crystal molecules of the liquid crystal layer, a Thin Film Transistor (TFT) that switches an electric signal supplied to the pixel electrode, and the like. As a driving method of liquid crystal molecules, a vertical electric field method such as a TN method and a VA method, and a lateral electric field method such as an IPS method and an FFS method are known. In the lateral electric field system, an electrode is formed only on one side of a substrate, and an electric field is applied in a direction parallel to the substrate, and a liquid crystal display element which has wider viewing angle characteristics and can display high quality is known as compared with the conventional vertical electric field system in which a voltage is applied to electrodes formed on upper and lower substrates to drive liquid crystal.

Although the transverse electric field type liquid crystal cell is excellent in viewing angle characteristics, since there are few electrode portions formed in the substrate, if the voltage holding ratio is low, a sufficient voltage is not applied to the liquid crystal, which indicates that the contrast is reduced. Further, if the stability of the liquid crystal alignment is small, the liquid crystal does not return to the initial state when the liquid crystal is driven for a long time, which causes a decrease in contrast and image sticking, and therefore, the stability of the liquid crystal alignment is important. Further, static electricity is easily accumulated in the liquid crystal cell, and even when positive and negative asymmetric voltages generated by driving are applied, electric charges are easily accumulated in the liquid crystal cell, and the accumulated electric charges are influenced and expressed in the form of disturbance of liquid crystal alignment and afterimage, thereby significantly reducing the display quality of the liquid crystal element. In addition, electric charges are accumulated even when a backlight is irradiated to the liquid crystal cell immediately after driving, and afterimages are generated even when the liquid crystal cell is driven for a short time; the size of flicker (flicker) in driving, and the like.

As a liquid crystal aligning agent having excellent voltage holding ratio and reduced charge accumulation when used in such a transverse electric field type liquid crystal display device, a liquid crystal aligning agent containing a specific diamine and an aliphatic tetracarboxylic acid derivative is disclosed (see patent document 1). As a method for shortening the afterimage disappearance time, there have been proposed a method using a liquid crystal alignment film having a low specific volume resistivity (see patent document 2) and a method using an alignment film having a volume resistivity that is not easily changed by a backlight of a liquid crystal display element (see patent document 3). However, as the performance of liquid crystal display elements has been improved, the performance required of liquid crystal alignment films has become more stringent, and it has been difficult to satisfy all the performance requirements of these conventional techniques.

Documents of the prior art

Patent document

Patent document 1: international laid-open publication WO2004/021076 pamphlet

Patent document 2: international laid-open publication WO2004/053583 pamphlet

Patent document 3: international publication WO2013/008822 pamphlet

Disclosure of Invention

Problems to be solved by the invention

The technical problem of the invention is to provide a liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal display element, wherein the liquid crystal aligning agent can obtain a liquid crystal aligning film which has excellent voltage holding ratio, fast relaxation of accumulated charges and difficult flicker (flicker) generation during driving.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that various properties are improved simultaneously by introducing a specific structure into a polymer contained in a liquid crystal aligning agent, and have completed the present invention.

The gist of the present invention is as follows.

1. A liquid crystal aligning agent comprising a polymer (A) having a structure represented by the following formula (1) and a polymer (B) having a structure represented by the following formula (2).

Wherein, in the formula (1), R¹Represents hydrogen or C1-3 alkyl, in formula (2), R²Is a single bond or a 2-valent organic radical, R³Is- (CH)₂)_n-a structure represented by (wherein n is an integer of 2 to 20, optionally-CH)₂-optionally substituted, in the absence of mutual adjacency, by a bond selected from the group consisting of ether, ester, amide, urea and carbamate, the hydrogen atoms of the amide and urea being optionally substituted by methyl or tert-butoxycarbonyl. ) R is⁴Is a single bond or a 2-valent organic group, any hydrogen atom on the phenyl ring being optionally substituted with a 1-valent organic group.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer (a) is at least 1 polymer selected from the group consisting of a polyimide precursor (a) which is a polycondensate of a diamine having a structure represented by the formula (1) and a tetracarboxylic dianhydride, and a polyimide (a) which is an imide thereof.

3. The liquid crystal aligning agent according to claim 1, wherein the polymer (B) is at least 1 polymer selected from the group consisting of a polyimide precursor (B) which is a polycondensate of a diamine having a structure represented by the formula (2) and a tetracarboxylic dianhydride, and a polyimide (B) which is an imide thereof.

4. The liquid crystal aligning agent according to 1 to 3, wherein the polyimide precursor (A) has a structural unit represented by the following formula (3).

Wherein, in the formula (3), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic radical derived from a diamine comprising the structure of formula (1), R¹⁰Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

5. The liquid crystal aligning agent according to the above 4, wherein in the formula (3), Y is₁Represented by any of the following formulae.

6. The liquid crystal aligning agent according to the above 4 or 5, wherein the polymer having the structural unit represented by the formula (3) is contained in an amount of 10 mol% or more based on the total polymer contained in the liquid crystal aligning agent.

7. The liquid crystal aligning agent according to 1 to 6, wherein the polyimide precursor (B) has a structural unit represented by the following formula (5).

Wherein, in the formula (5), X³Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y³Is a 2-valent organic group derived from a diamine comprising the structure of formula (2), R¹³Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

8. The liquid crystal aligning agent according to any one of claims 1 to 7, wherein the content of the polymer (A) is 10 to 95% by mass and the content of the polymer (B) is 5 to 90% by mass, based on the total amount of the polymer (A) and the polymer (B).

9. The liquid crystal aligning agent according to any one of the above 1 to 8, which contains an organic solvent for dissolving the polymer (A) and the polymer (B).

10. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of 1 to 9.

11. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.

12. The liquid crystal display element according to claim 11, wherein the liquid crystal display element is of a lateral electric field driving type.

13. The liquid crystal display element according to 11 or 12, wherein the liquid crystal display element is of an FFS type.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film which has a rapid relaxation of accumulated charges and is less likely to cause flicker (flicker) during driving, and a liquid crystal display element having excellent display characteristics are provided. The reason why the above-described characteristics can be obtained by the present invention is not clear, but is generally considered as follows. The structure of the above (1) contained in the polymer contained in the liquid crystal aligning agent of the present invention has a conjugated structure. This can promote the movement of charges and the relaxation of accumulated charges in the liquid crystal alignment film, for example.

Detailed Description

The liquid crystal aligning agent of the present invention is characterized by containing a specific polymer (A) having a structure represented by the formula (1) and a specific polymer (B) having a structure represented by the formula (2).

The content of the specific polymer (A) is 10 to 95% by mass, more preferably 60 to 90% by mass, based on the total amount of the specific polymer (A) and the specific polymer (B). The content of the specific polymer (B) is 90 to 5% by mass, and more preferably 40 to 10% by mass, based on the total amount of the specific polymer (A) and the specific polymer (B). If the specific polymer (A) is too small, the charge accumulation property and the rubbing resistance of the liquid crystal alignment film are deteriorated; if the specific polymer (B) is too small, the alignment properties and alignment control ability of the liquid crystal are deteriorated. The specific polymer (a) and the specific polymer (B) contained in the liquid crystal aligning agent of the present invention may be 1 type or 2 or more types, respectively.

< specific Polymer (A) >

The specific polymer (A) is a polymer having a structure represented by the above formula (1).

R in the formula (1) from the viewpoint of solubility of the resulting polymer¹Preferably an alkyl group having 1 to 3 carbon atoms, and preferably a methyl group, from the viewpoint of not impairing the liquid crystal alignment properties.

In the above formula (1), 1 or more of any hydrogen atoms on the benzene ring are optionally substituted with a 1-valent organic group other than the primary amino group. Examples of the 1-valent organic group include: alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, fluoroalkyl group having 1 to 20 carbon atoms, fluoroalkenyl group having 2 to 20 carbon atoms, fluoroalkoxy group having 1 to 20 carbon atoms, cyclohexyl group, phenyl group, fluorine atom, or a combination thereof. From the viewpoint of liquid crystal alignment properties, a 1-valent organic group selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, a fluoroalkenyl group having 2 to 4 carbon atoms, and a fluoroalkoxy group having 1 to 4 carbon atoms is preferred. More preferably, the structure of formula (1) is a structure in which a hydrogen atom on a benzene ring is unsubstituted.

The specific polymer (a) in the present invention is preferably a polymer obtained using a diamine having a structure represented by the above formula (1). Specific examples of such polymers include: polyamic acids, polyamic acid esters, polyimides, polyureas, polyamides, and the like. Among them, the specific polymer (a) is preferably at least one selected from polyimide precursors having a structural unit represented by the following formula (3) and polyimides which are imide compounds thereof, from the viewpoint of use as a liquid crystal aligning agent.

Wherein, in the formula (3), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic radical derived from a diamine comprising the structure of formula (1), R¹⁰Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. From the viewpoint of easiness of imidation by heating, R¹⁰Preferably a hydrogen atom, a methyl group or an ethyl group.

The polyimide precursor (A) is a polymer obtained by polycondensation of a diamine having a structure represented by the above formula (1) and a tetracarboxylic acid derivative, X in the formula (3)₁Is a 4-valent organic group derived from the tetracarboxylic acid derivative. The tetracarboxylic acid derivative, preferably tetracarboxylic dianhydride, can be appropriately selected depending on the degree of the desired characteristics such as solubility of the polymer in a solvent, coatability of a liquid crystal aligning agent, alignment of a liquid crystal when forming a liquid crystal alignment film, voltage holding ratio, accumulated charge, and the like, and 1 kind or 2 or more kinds may be mixed in the same polymer.

If X in the formula (3) is indicated₁Specific examples of (4) include the structures of formulae (X-1) to (X-46) described in International patent publication No. 2015/119168, pages 13 to 14.

Preferred X is shown below₁The structures (A-1) to (A-21) are not limited to these structures.

Among the above structures, (A-1) and (A-2) are particularly preferable from the viewpoint of further improving the abrasion resistance, (A-4) is particularly preferable from the viewpoint of further improving the relaxation rate of the accumulated charge, and (A-15) to (A-17) are particularly preferable from the viewpoint of further improving the liquid crystal alignment property and the relaxation rate of the accumulated charge.

As Y in formula (3)₁Specific examples of (3) include the structure of the above formula (1). A diamine having a structure of formula (1) is described in Japanese patent laid-open No. 2009-75140, and can be produced by the production method described in this publication.

In the specific polymer (a) of the present invention, it is preferable that at least 1 structural unit selected from the structural unit represented by the above formula (3) and the structural unit imidized therewith is contained in an amount of 5 to 100 mol% based on the total structural units of the specific polymer (a), and from the viewpoint of having both liquid crystal alignment properties and relaxation properties of accumulated charges, it is more preferable that the amount is contained in an amount of 10 to 100 mol%, and it is even more preferable that the amount is contained in an amount of 20 to 100 mol%.

The specific polymer (a) may have a structural unit represented by the following formula (4) and/or a structural unit obtained by imidizing the structural unit, in addition to the structural unit represented by the formula (3).

In the formula (4), X₂Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₂Is a 2-valent organic group derived from a diamine not having a structure of formula (1) in the main chain direction, R¹¹And R of said formula (3)¹⁰Are as defined for R¹²Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. And, preferably two R¹²At least one of which is a hydrogen atom.

As X₂Specific examples of (3) include preferred examples, and X in the formula (3)₁Those illustrated. In addition, Y₂Is a 2-valent organic group derived from a diamine not having the structure of formula (1) in the main chain direction, and the structure thereof is not particularly limited. In addition, for Y₂May be based on polymerizationThe degree of the desired properties such as solubility of the substance in a solvent, coatability of a liquid crystal aligning agent, alignment of liquid crystal when forming a liquid crystal alignment film, voltage holding ratio, accumulated charge and the like is appropriately selected, and 1 kind or 2 or more kinds may be mixed in the same polymer.

If prompt Y₂Specific examples of (3) include: the structure of formula (2) described on page 4 of International publication No. 2015/119168 and the structures of formulae (Y-1) to (Y-97), (Y-101) to (Y-118) described on pages 8 to 12; a 2-valent organic group obtained by removing 2 amino groups from formula (2) described on page 6 of International publication No. 2013/008906; a 2-valent organic group obtained by removing 2 amino groups from formula (1) described on page 8 of International publication No. 2015/122413; a structure of formula (3) described on page 8 of International publication No. 2015/060360; a 2-valent organic group obtained by removing 2 amino groups from the formula (1) described on page 8 of Japanese laid-open patent publication No. 2012-173514; a 2-valent organic group obtained by removing 2 amino groups from the formulae (A) to (F) described on page 9 of International publication No. 2010-050523.

Preferred Y is shown below₂The present invention is not limited to these structures.

Y is above₂Of the structures (A) and (B) of (B-28) and (B-29) are particularly preferable from the viewpoint of further improving the rubbing resistance, (B-1) to (B-3) are particularly preferable from the viewpoint of further improving the liquid crystal alignment property, (B-14) to (B-18) and (B-27) are particularly preferable from the viewpoint of further improving the relaxation rate of the accumulated charges, and (B-26) is particularly preferable from the viewpoint of further improving the voltage holding ratio.

When the specific polymer (a) has the structural unit represented by formula (3) and the structural unit represented by formula (4), the structural unit represented by formula (3) is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more, based on the total of formula (3) and formula (4).

The molecular weight of the polyimide precursor constituting the specific polymer (A) in the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000 in terms of weight average molecular weight.

The polyimide constituting the specific polymer (A) is obtained by ring-closing a polyimide precursor having a structural unit represented by formula (3) and, if necessary, a structural unit represented by formula (4). In this polyimide, the ring-closure ratio of amic acid groups (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 in which a solution of the polyimide precursor is directly heated, and catalytic imidization in which a catalyst is added to a solution of the polyimide precursor.

< specific Polymer (B) >

The specific polymer (B) contained in the liquid crystal aligning agent of the present invention is a polymer having a structure represented by the following formula (2).

Wherein, in the formula (2), R²Is a single bond or a 2-valent organic group, preferably a single bond. R³Is- (CH)₂)_n-the structure shown. n is an integer of 2 to 10, preferably 3 to 7. In addition, any of-CH₂Optionally substituted, in the absence of proximity to each other, by ether, ester, amide, urea, or carbamate linkages, the hydrogen atoms of the amide and urea being optionally substituted by methyl or tert-butoxycarbonyl groups. R⁴Is a single bond or a 2-valent organic group. Any hydrogen atom on the benzene ring is optionally substituted with a 1-valent organic group, with the substituent preferably being a fluorine atom or a methyl group.

Specific examples of the structure represented by formula (2) include the following structures, but are not limited to these structures.

As the specific polymer (B) in the present invention, a polymer obtained using a diamine having a structure represented by the above formula (2) is preferable. Specific examples of the polymer include: polyamic acids, polyamic acid esters, polyimides, polyureas, polyamides, and the like. From the viewpoint of use as a liquid crystal aligning agent, the specific polymer (B) is preferably at least 1 selected from polyimide precursors containing a structural unit represented by the following formula (5) and polyimides which are imide compounds thereof.

Wherein, in the formula (5), X³Is a 4-valent organic group derived from a tetracarboxylic acid derivative. Specifically, at least 1 kind selected from the group consisting of structures represented by the following formulae (X1-1) to (X1-45) is preferable.

In the formula (X1-1), R⁵、R⁶、R⁷And R⁸Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group or a phenyl group. From the viewpoint of liquid crystal alignment, R⁵、R⁶、R⁷And R⁸Preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group.

Among these, X is X from the viewpoint of liquid crystal alignment properties and reliability³Preferably (X1-10), (X1-11) or (X1-29), more preferably (X1-10) or (X1-11).

In the formula (5), Y³Is a 2-valent organic group derived from a diamine containing the structure of formula (2), wherein R in formula (2) is⁴Preferred are single bonds or 2-valent organic groups derived from diamines of the benzene ring. R¹³The alkyl group is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and is particularly preferably a hydrogen atom or a methyl group from the viewpoint of easiness of imidation by heating.

In the specific polymer (B) of the present invention, at least 1 structural unit selected from the structural unit represented by the above formula (5) and the structural unit imidized therewith is preferably contained in a ratio of 20 to 100 mol% with respect to the total structural units in the specific polymer (B), and from the viewpoint of compatibility between liquid crystal alignment and reliability, more preferably 30 to 70 mol%, and still more preferably 50 to 70 mol%.

The specific polymer (B) in the present invention may have a structural unit represented by the following formula (6) and/or a structural unit imidized therewith, in addition to the structural unit represented by the above formula (5).

Wherein, in the formula (6), R¹⁴And R of said formula (5)¹³The same definition is applied. X₄Is a 4-valent organic group derived from a tetracarboxylic acid derivative, and the structure thereof is not particularly limited. Specific examples thereof include the structures of the above formulae (X1-1) to (X-45).

In the above formula (6), Y₄Is a 2-valent organic group derived from a diamine, and the structure thereof is not particularly limited. If Y is enumerated₄Specific examples of (A) include the following structures of formulae (Y-1) to (Y-138).

The ratio of the structural unit imidized with respect to the structural unit of the polyimide precursor (also referred to as imidization ratio) contained in each of the specific polymer (a) and the specific polymer (B) can be arbitrarily adjusted depending on the characteristics of the liquid crystal aligning agent. The imidization ratio in the specific polymer (a) is preferably 0 to 55%, more preferably 0 to 20%, from the viewpoint of solubility and charge accumulation characteristics. In addition, the imidization ratio in the specific polymer (B) is preferably high, preferably 40 to 95%, more preferably 55 to 90%, from the viewpoint of the alignment property, alignment controllability, and voltage holding ratio of the liquid crystal.

< method for producing polyamic acid ester >

The polyamic acid ester which is a polyimide precursor used in the present invention can be synthesized by the following method (1), (2) or (3).

(1) Case of Synthesis from Polyamic acid

The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from a tetracarboxylic dianhydride and a diamine.

Specifically, the polyamic acid can be synthesized by reacting a polyamic acid with an esterifying agent in the presence of an organic solvent at-20 to 150 ℃ and preferably 0 to 50 ℃ for 30 minutes to 24 hours, preferably 1 to 4 hours.

The esterification agent is preferably an esterification agent which can be easily removed by purification, and examples thereof include N, N-dimethylformamide dimethyl acetal, N-dimethylformamide diethyl acetal, N-dimethylformamide dipropyl acetal, N-dimethylformamide dineopentylbutyl acetal, N-dimethylformamide di-tert-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, and 4- (4, 6-dimethoxy-1, 3, 5-triazin-2-yl) -4-methylmorpholinium chloride. The amount of the esterifying agent added is preferably 2 to 6 molar equivalents relative to 1 mole of the repeating unit of the polyamic acid.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ -butyrolactone from the viewpoint of solubility of the polymer, and 1 kind or 2 or more kinds mixed may be used. The concentration during synthesis is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of a polymer hardly occurs and a high molecular weight product is easily obtained.

(2) Case of synthesis by reaction of tetracarboxylic acid diester dichloride and diamine

The polyamic acid ester can be synthesized from a tetracarboxylic acid diester dichloride and a diamine.

Specifically, the tetracarboxylic acid diester dichloride and the diamine can be synthesized by reacting at-20 to 150 ℃, preferably 0 to 50 ℃ for 30 minutes to 24 hours, preferably 1 to 4 hours in the presence of a base and an organic solvent.

Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, but pyridine is preferable for mild reaction progress. The amount of the base to be added is preferably 2 to 4 times by mol based on the tetracarboxylic acid diester dichloride, from the viewpoint of ease of removal and availability of a high molecular weight product.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ -butyrolactone from the viewpoint of solubility of the monomer and the polymer, and 1 or 2 or more of them may be used in combination. The polymer concentration during synthesis is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer is not likely to occur and a high molecular weight product is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and is preferably kept from being mixed with external air in a nitrogen atmosphere.

(3) Case of synthesis from tetracarboxylic acid diester and diamine

The polyamic acid ester can be synthesized by polycondensing a tetracarboxylic acid diester and a diamine.

Specifically, the tetracarboxylic acid diester can be synthesized by reacting a tetracarboxylic acid diester with a diamine in the presence of a condensing agent, a base, and an organic solvent at 0 to 150 ℃, preferably 0 to 100 ℃, for 30 minutes to 24 hours, preferably 3 to 15 hours.

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N ' -carbonyldiimidazole, dimethoxy-1, 3, 5-triazinylmethyl morpholinium, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium hexafluorophosphate, diphenyl (2, 3-dihydro-2-thio-3-benzoxazolyl) phosphonate, and the like can be used. The amount of the condensing agent to be added is preferably 2 to 3 times by mol based on the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be added is preferably 2 to 4 times by mol based on the diamine component, from the viewpoint of ease of removal and availability of a high molecular weight material.

In addition, in the above reaction, the reaction proceeds efficiently by adding a lewis acid as an additive. The lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The amount of the Lewis acid added is preferably 0 to 1.0 mol per mol of the diamine component.

Among the above-mentioned 3 methods for synthesizing polyamic acid esters, the method for synthesizing polyamic acid ester (1) or (2) is particularly preferable because a polyamic acid ester having a high molecular weight can be obtained.

The solution of the polyamic acid ester obtained as described above can be poured into a poor solvent while sufficiently stirring to precipitate a polymer. The resulting polyamide acid ester is precipitated several times, washed with a poor solvent, and dried at room temperature or under heating to obtain a purified polyamide acid ester powder. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

< Synthesis of Polyamic acid >

When the polyamic acid, which is the polyimide precursor in the specific polymer (a) and the specific polymer (B), is obtained by the reaction of tetracarboxylic dianhydride and diamine, a method of mixing tetracarboxylic dianhydride and diamine in an organic solvent and reacting them is preferable.

The organic solvent used in the above reaction is not particularly limited as long as the polyamic acid produced is soluble, and specific examples thereof include: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ -butyrolactone, etc. These may be used alone or in combination. Further, even a solvent which does not dissolve the polyamic acid may be used in combination with the above solvent within a range where the produced polyamic acid is not precipitated. In addition, since the water content in the organic solvent suppresses the polymerization reaction and further causes hydrolysis of the formed polyamic acid, it is preferable to use an organic solvent which is dehydrated and dried as much as possible.

Examples of the method for mixing the tetracarboxylic dianhydride component and the diamine component in the organic solvent include: a method of adding a tetracarboxylic dianhydride component directly by stirring a solution obtained by dispersing or dissolving a diamine component in an organic solvent, or adding a tetracarboxylic dianhydride component by dispersing or dissolving in an organic solvent; conversely, a method of adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic dianhydride component in an organic solvent; a method of alternately adding a tetracarboxylic dianhydride component and a diamine component, and the like, and any of these methods can be used in the present invention. When the tetracarboxylic dianhydride component or the diamine component is composed of a plurality of compounds, these may be reacted in a state where these plurality of components are mixed in advance, or may be reacted in sequence.

The reaction temperature of the tetracarboxylic dianhydride component and the diamine component in the organic solvent is usually 0 to 150 ℃, preferably 5 to 100 ℃, and more preferably 10 to 80 ℃. The higher the temperature, the faster the polymerization reaction is completed, but if the temperature is too high, a polymer of high molecular weight is sometimes not obtained. In addition, the reaction may be carried out at an arbitrary concentration, but if the concentration is too low, it is difficult to obtain a polymer of high molecular weight; if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring becomes difficult, so that it is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction is carried out at a high concentration in the initial stage, and then an organic solvent may be added.

The ratio of the tetracarboxylic dianhydride component and the diamine component used in the polymerization reaction of the polyamic acid is preferably 1: 0.8 to 1.2. In addition, since the polyamic acid obtained by excessively adding the diamine component may be heavily colored in the solution, when the solution is intended to be colored, the ratio is set to 1: 0.8 to 1. As in the usual polycondensation reactions, the closer the molar ratio is to 1: 1, the larger the molecular weight of the obtained polyamic acid. If the molecular weight of the polyamic acid is too small, the strength of the coating film obtained therefrom may be insufficient; on the other hand, if the molecular weight of the polyamic acid is too large, the viscosity of the liquid crystal alignment agent produced by the method becomes too high, and workability in forming a coating film and uniformity of the coating film may be deteriorated. Therefore, the polyamic acid used in the liquid crystal aligning agent of the present invention is preferably 0.1 to 2.0 in reduced viscosity (concentration of 0.5dl/g, 30 ℃ in NMP), more preferably 0.2 to 1.5.

When the solvent used for polymerization of polyamic acid is not required to be contained in the liquid crystal aligning agent of the present invention, or when unreacted monomer components and impurities are present in the reaction solution, the precipitation recovery and purification are not required. The polyamic acid solution is preferably introduced into a poor solvent under stirring to precipitate and recover the polyamic acid solution. The poor solvent for precipitation recovery of the polyamic acid is not particularly limited, and there can be exemplified: methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and the like. The polyamic acid precipitated by introducing the poor solvent may be filtered, washed, and recovered, and then dried at normal temperature or under reduced pressure or by heating to be powdered. The powder is further dissolved in a good solvent, and the reprecipitation operation is repeated 2 to 10 times to purify the polyamic acid. This purification step is preferably carried out if the impurities cannot be completely removed in a single precipitation recovery operation. In this case, the use of 3 or more kinds of poor solvents such as alcohols, ketones, hydrocarbons and the like is preferable because the purification efficiency is further improved.

< method for producing polyimide >

The polyimide in the specific polymer (a) and the specific polymer (B) can be produced by imidizing the polyamic acid ester or polyamic acid, which is a polyimide precursor.

In the case of producing a polyimide from a polyamic acid ester, chemical imidization by adding a basic catalyst to the polyamic acid ester solution or a polyamic acid solution obtained by dissolving a polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferred because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization.

In the case of producing a polyimide from a polyamic acid, chemical imidization by adding a catalyst to a solution of the polyamic acid obtained by the reaction of a diamine component and a tetracarboxylic dianhydride is simple. Chemical imidization is preferred because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization.

Chemical imidization can be carried out by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the polymerization reaction described above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a suitable basicity for the progress of the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride, and among these, acetic anhydride is preferable because purification after completion of the reaction is easy.

The temperature for the imidization reaction is-20 to 140 ℃, preferably 0 to 100 ℃, and the reaction can be carried out for 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, by mole the amount of the amic acid group, and the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, by mole the amount of the amic acid group. The imidization ratio of the obtained polymer can be controlled by adjusting the amount of the catalyst, the temperature, and the reaction time.

Since the catalyst and the like added remain in the polyamic acid ester or the solution after the imidization of the polyamic acid, it is preferable to form the liquid crystal aligning agent of the present invention by recovering the obtained imidized polymer and redissolving it in an organic solvent by the following means.

The solution of the polyimide obtained as described above can be injected into a poor solvent while sufficiently stirring, thereby allowing a polymer to be precipitated. The polyamic acid ester is precipitated several times, washed with a poor solvent, and dried at room temperature or under heating to obtain a purified polyamic acid ester powder.

The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

< liquid Crystal alignment agent >

The liquid crystal aligning agent of the present invention contains the specific polymer (A) and the specific polymer (B). The specific polymer (a) and the specific polymer (B) contained in the liquid crystal aligning agent of the present invention may be 1 type or 2 or more types, respectively.

In addition, other polymers, that is, polymers having neither a 2-valent group represented by formula (1) nor a 2-valent group represented by formula (2), may be contained in addition to the specific polymers (a) and (B). Examples of corresponding further polymers are: polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or a derivative thereof, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like.

When the liquid crystal aligning agent of the present invention contains another polymer, the content ratio of the specific polymer (a) and the specific polymer (B) in total in the entire polymer components is preferably 5% by mass or more, and examples thereof include 5 to 95% by mass.

The liquid crystal aligning agent is preferably in the form of a coating solution from the viewpoint of forming a uniform film, and is preferably a coating solution containing a polymer component and an organic solvent for dissolving the polymer component. At this time, the content (concentration) of the polymer in the liquid crystal aligning agent can be appropriately changed by setting the thickness of the coating film to be formed. It is preferably 1% by mass or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10% by mass or less from the viewpoint of storage stability of the solution. The content of the polymer is particularly preferably 2 to 8% by mass.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as the organic solvent is an organic solvent in which the polymer 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, 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, a mixed solvent of a solvent which improves coatability when the liquid crystal aligning agent is applied and surface smoothness of a coating film is usually used as the organic solvent contained in the liquid crystal aligning agent, and such a mixed solvent is also suitable for the liquid crystal aligning agent of the present invention. Specific examples of the organic solvent used in combination are listed below, but not limited to these examples.

Examples thereof include: ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentanol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2, 6-dimethyl-4-heptanol, 1, 2-ethanediol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethyl-1, 3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, 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, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2, 6-dimethyl-4-heptanone, 4, 6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, propylene glycol, and propylene glycol, and propylene glycol, and propylene glycol, and propylene glycol ether, Tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, 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, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionate, propyl 3-methoxypropionate, propylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol acetate, triethylene glycol monoethyl ether acetate, triethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, propylene glycol monoethyl, Butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and solvents represented by the following formulae [ D-1] to [ D-3 ].

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

Among them, preferable combinations of solvents include: n-methyl-2-pyrrolidone and γ -butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ pyrrol-olactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ pyrrol-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ -butyrolactone and propylene glycol monobutyl ether and 2, 6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and γ -butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ pyrrol-butyrolactone and propylene glycol monobutyl ether and 2, 6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone, gamma-butyrolactone, dipropylene glycol dimethyl ether, and the like. The kind and content of the solvent can be appropriately selected depending on the coating apparatus, coating conditions, coating environment, and the like of the liquid crystal aligning agent.

In order to improve the adhesion of the coating film to the substrate, an additive such as a silane coupling agent may be added to the liquid crystal aligning agent of the present invention, and other resin components may be added.

Examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy-containing compound, and examples thereof include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 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-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-glycidoxypropyltrimethoxysilane, N-glycidoxypropyltriethoxysilane, N-glycidoxypropyltrimethoxysilane, 2-trimethoxysilane, 2-glycidoxypropyltrimethoxysilane, 2-trimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-glycidoxypropyltrimethoxysilane, 3-trimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilane, 3-alkoxysilane, and the like, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, 4, 7-triazodecane, 10-triethoxysilyl-1, 4, 7-triazodecane, 9-trimethoxysilyl-3, 6-diazanonylacetate, 9-triethoxysilyl-3, 6-diazanonylacetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-trimethoxysilylpropyltriethoxysilane, N-bis (oxyethylene) -3-amino-propyltrimethoxysilane, N-trimethoxysilylpropylsilane, N-hydroxysilane, N-bis (oxypropylene) -1, N-trisilane, N-methoxysilylpropylsilane, N-1-triazacyclo-1, N-1-triazacyclo-3-1-triazacyclo-one, N-t-ethyl-3-triazacyclo-3-one, N-t-ethyl-3-one, N-t-one, N-one, N-one, N-one, N-one, N-one, N-one, N, n-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2, 4-hexanediol, N, n, N ', -tetraglycidyl-m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, or N, N ', -tetraglycidyl-4, 4' -diaminodiphenylmethane, and the like.

In addition, the following additives may be added to the liquid crystal aligning agent of the present invention in order to improve the mechanical strength of the film.

These additives are preferably 0.1 to 30 parts by mass per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. If the amount is less than 0.1 part by mass, the effect cannot be obtained, and if the amount exceeds 30 parts by mass, the orientation of the liquid crystal is lowered, and therefore, the amount is more preferably 0.5 to 20 parts by mass.

< liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is obtained from the liquid crystal aligning agent. As an example of a method for obtaining a liquid crystal alignment film from a liquid crystal alignment agent, there is a method in which a liquid crystal alignment agent in the form of a coating liquid is applied to a substrate, dried and fired to obtain a film, and the film is subjected to an alignment treatment by a brush-polishing treatment or a photo-alignment treatment.

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 glass substrate or a silicon nitride substrate may be used, or a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used. In this case, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed in view of process simplification. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used if only one substrate is formed, and a material that reflects light such as aluminum may be used for the electrodes in this case.

The method of applying the liquid crystal aligning agent is not particularly limited, and screen printing, offset printing, flexographic printing, inkjet printing and the like are industrially common. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray 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 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. In general, the solvent is removed sufficiently under the conditions of firing at 50 to 120 ℃ for 1 to 10 minutes and then at 150 to 300 ℃ for 5 to 120 minutes.

The thickness of the liquid crystal alignment film after firing is not particularly limited, and if it is too thin, the reliability of the liquid crystal display device may be lowered, and therefore, it is preferably 5 to 300nm, more preferably 10 to 200 nm.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a liquid crystal display device of a transverse electric field system such as an IPS system or an FFS system, and is particularly suitable as a liquid crystal alignment film for a liquid crystal display device of an FFS system.

< liquid Crystal display element >

The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent, then fabricating a liquid crystal cell by a known method, and forming an element using the liquid crystal cell.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that the liquid crystal display element may be an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display.

Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and segment electrodes are provided on the other substrate. These electrodes may be formed as ITO electrodes, for example, and patterned so as to achieve a desired image representation. Then, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film may be, for example, SiO formed by a sol-gel method₂-TiO₂The film formed. Next, under the above conditions, a liquid crystal alignment film was formed on each substrate.

Next, for example, an ultraviolet-curable sealing material is disposed at a predetermined position on one of two substrates on which liquid crystal alignment films are formed, liquid crystal is further disposed at several predetermined positions on the surface of the liquid crystal alignment film, the other substrate is bonded and pressure-bonded so that the liquid crystal alignment films face each other, and the sealing material is cured by irradiating ultraviolet rays onto the entire surface of the substrate to obtain a liquid crystal cell.

Alternatively, as a step after forming a liquid crystal alignment film on a substrate, when a sealing material is disposed at a predetermined position on one substrate, an opening portion capable of being filled with liquid crystal from the outside is provided in advance, the substrates are bonded without disposing liquid crystal, then a liquid crystal material is injected into the liquid crystal cell through the opening portion provided on the sealing material, and the opening portion is sealed with an adhesive to obtain a liquid crystal cell. The liquid crystal material may be injected by a vacuum injection method or a method using a capillary phenomenon in the atmosphere.

In any of the above methods, in order to secure a space for filling the liquid crystal cell with the liquid crystal material, it is preferable to adopt: the present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device, which includes providing columnar projections on a substrate, spreading spacers on a substrate, mixing spacers in a sealing material, or a combination thereof.

The liquid crystal material includes nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable, and either of positive liquid crystal material and negative liquid crystal material can be used. Next, a polarizing plate is provided. Specifically, a pair of polarizing plates is preferably attached to the surfaces of the 2 substrates opposite to the liquid crystal layer.

The liquid crystal display element of the present invention is not limited to the above description as long as the liquid crystal aligning agent of the present invention is used, and can be produced by other known methods. For example, a process for obtaining a liquid crystal display element is disclosed in the paragraphs from 17 th page 0074 to 19 th page 0081 of japanese patent application laid-open No. 2015-135393.

Examples

The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples. The compounds and solvents are abbreviated as follows.

NMP: n-methyl-2-pyrrolidone GBL: gamma-butyrolactone

BCS: butyl cellosolve

< viscosity >

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

< measurement of imidization Rate >

The imidization ratio of the polyimide was measured as follows. 30mg of the polyimide powder was put into an NMR (nuclear magnetic resonance) sample tube (. phi.5, manufactured by Softweed scientific Co., Ltd.), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53ml) was added thereto, and the mixture was dissolved completely by applying ultrasonic waves. The proton NMR at 500MHz was measured with an NMR spectrometer (JNW-ECA500) (manufactured by JEOL DATUM LTD.). The imidization ratio was determined as follows: the proton derived from the structure which did not change before and after imidization was identified as a reference proton, and the peak cumulative value of this proton and the peak cumulative value of the proton derived from the NH group of amic acid appearing in the vicinity of 9.5ppm to 10.0ppm were used to obtain the following formula.

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

In the above formula, x represents a peak accumulation value of a proton derived from an NH group of amic acid, y represents a peak accumulation value of a reference proton, and α represents a ratio of the number of protons of the reference proton to 1 NH group of amic acid (imidization ratio of 0%).

(Synthesis example 1)

DA-154.7 g (224 mmol) and DA-253.4 g (95.9 mmol) were weighed out in a 1L four-necked flask equipped with a stirrer and a nitrogen inlet, and NMP 613g was added thereto, and the mixture was stirred and dissolved while feeding nitrogen. The diamine solution was stirred with water, and then, while adding 189.5 g (298 mmol) of CA-and 175g of NMP, stirred at 23 ℃ for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 890 mPas).

900g of the polyamic acid solution was taken out from a 3L Erlenmeyer flask equipped with a stirrer, and NMP1350g, acetic anhydride 74.3g and pyridine 34.6g were added thereto, and after stirring at room temperature for 30 minutes, the mixture was reacted at 40 ℃ for 2 hours. The reaction solution was poured into 8300g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder (imidization rate: 66%).

50.7g of the polyimide powder was taken out from a500 mL Erlenmeyer flask equipped with a stirrer, and NMP372g was added thereto and dissolved by stirring at 50 ℃ for 20 hours. Further, 11.9g of this solution was taken out from a 200mL Erlenmeyer flask equipped with a stirrer, and 4.49g of NMP, 5.86g of GBL, 1.19g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and 5.86g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a polyimide solution (SPI-1).

(Synthesis example 2)

DA-186.0 g (352 mmol), DA-253.4 g (95.9 mmol) and DA-376.5 g (191 mmol) were weighed out in a 1L four-necked flask equipped with a stirrer and a nitrogen inlet, and NMP 1580g was added thereto, and the mixture was stirred and dissolved while feeding nitrogen. The diamine solution was stirred with water, and then added with CA-293.2 g (416 mmol), and further added with NMP 168g, and stirred at 40 ℃ for 3 hours under a nitrogen atmosphere. CA-328.2 g (143 mmol) and NMP 160g were further added thereto, and the mixture was stirred at 23 ℃ for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 200 mPas).

800g of the polyamic acid solution was taken out from a 3L Erlenmeyer flask equipped with a stirrer, and NMP700g, acetic anhydride 69.7g and pyridine 18.0g were added thereto, and after stirring at room temperature for 30 minutes, the mixture was reacted at 55 ℃ for 3 hours. The reaction solution was poured into 5600g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder (imidization rate: 75%).

20.3g of the polyimide powder was taken out from a 300mL Erlenmeyer flask equipped with a stirrer, NMP148g was added, and the mixture was stirred at 50 ℃ for 20 hours to dissolve the polyimide powder. Further, 6.31g of this solution was taken out from a 200mL Erlenmeyer flask equipped with a stirrer, and 2.06g of NMP, 3.00g of GBL, 0.630g of NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and 3.00g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a polyimide solution (SPI-2).

(Synthesis example 3)

DA-193.8 g (384 mmol), DA-351.0 g (128 mmol) and DA-443.7 g (128 mmol) were weighed out in a 1L four-necked flask equipped with a stirrer and a nitrogen inlet, and 1380g of NMP was added thereto, and stirred and dissolved while feeding nitrogen. The diamine solution was stirred with water, and while adding CA-293.2 g (416 mmol), NMP 214g was added thereto, and the mixture was stirred at 40 ℃ for 3 hours under a nitrogen atmosphere. Further, CA-332.6 g (166 mmol) and NMP 185g were added thereto, and the mixture was stirred at 23 ℃ for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 200 mPas).

700g of the polyamic acid solution was taken out from a 3L Erlenmeyer flask equipped with a stirrer, and NMP612g, 60.4g of acetic anhydride and 15.6g of pyridine were added thereto, and after stirring at room temperature for 30 minutes, the mixture was reacted at 55 ℃ for 3 hours. The reaction solution was poured into 4900g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder (imidization rate: 75%).

18.1g of the polyimide powder was taken out from a 200mL Erlenmeyer flask equipped with a stirrer, NMP132g was added thereto, and the mixture was stirred at 50 ℃ for 20 hours to dissolve the polyimide powder. Further, 5.54g of the solution was collected, and 2.09g of NMP, 2.73g of GBL, 0.550g of an NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and 2.73g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a polyimide solution (SPI-3).

(Synthesis example 4)

In a 100mL four-necked flask equipped with a stirrer and a nitrogen inlet, 56.31 g (16.0 mmol) of DA was weighed, 47.6g of NMP was added, and stirring and dissolution were carried out while feeding nitrogen. The diamine solution was stirred with water, and added with CA-31.69 g (8.61 mmol) and NMP10.2g, followed by stirring at 23 ℃ for 3 hours under a nitrogen atmosphere. CA-41.39 g (6.37 mmol) was added thereto, and NMP10.2g was further added thereto, followed by stirring at 50 ℃ for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 250 mPas).

14.4g of the solution of polyamic acid was taken out from a 100mL Erlenmeyer flask equipped with a stirrer, and NMP8.39g, GBL 8.08g, 1.44g of an NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane, and BCS 8.08g were added, followed by stirring with a magnetic stirrer for 2 hours to obtain a solution of polyamic acid (PAA-1).

(Synthesis example 5)

A100 mL four-necked flask equipped with a stirrer and a nitrogen inlet was charged with DA-64.41 g (40.7 mmol) and DA-71.79 g (7.20 mmol), and 55.8g of NMP was added thereto and stirred and dissolved while feeding nitrogen. The diamine solution was stirred with water, and CA-114.0 g (46.6 mmol) and NMP 23.7g were added thereto, followed by stirring at 23 ℃ for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 815 mPas).

30g of the polyamic acid solution was taken out from a 200mL Erlenmeyer flask equipped with a stirrer, and NMP45g, acetic anhydride 3.64g and pyridine 1.69g were added thereto, and after stirring at room temperature for 30 minutes, the mixture was reacted at 40 ℃ for 3 hours. The reaction solution was poured into 300g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder (imidization rate: 73%).

In a 100mL conical flask equipped with a stirrer, 4.10g of the polyimide powder was taken out, 30.6g of NMP30 was added, and the mixture was stirred at 50 ℃ for 20 hours to dissolve the polyimide powder. Further, 6.94g of this solution was taken out from a 100mL Erlenmeyer flask equipped with a stirrer, and 4.09g of NMP, 3.91g of GBL, 0.69g of NMP solution containing 1 mass% 3-glycidoxypropyltriethoxysilane, and 3.91g of BCS were added thereto, followed by stirring with a magnetic stirrer for 2 hours to obtain a polyimide solution (SPI-4).

(Synthesis example 6)

DA-87.93 g (20.0 mmol) was weighed out in a 100mL four-necked flask equipped with a stirrer and a nitrogen inlet, 87.0g of NMP was added thereto, and the mixture was stirred and dissolved while feeding nitrogen. This diamine solution was stirred with water, and while adding CA-32.23 g (11.4 mmol), NMP10.0g was added, and stirred at 23 ℃ for 3 hours under a nitrogen atmosphere. CA-41.74 g (8.00 mmol) and NMP 10.1g were added thereto, and the mixture was stirred at 50 ℃ for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 140 mPas).

6.91g of the solution of polyamic acid was taken out from a 100mL Erlenmeyer flask equipped with a stirrer, and NMP1.35g, GBL 2.98g, NMP solution containing 1 mass% of 3-glycidoxypropyltriethoxysilane 0.69g, and BCS 2.98g were added, followed by stirring with a magnetic stirrer for 2 hours to obtain a solution of polyamic acid (PAA-2).

(example 1)

2.13g of the polyimide solution (SPI-1) obtained in Synthesis example 1 and 8.47g of the polyamic acid solution (PAA-1) obtained in Synthesis example 4 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-1).

(example 2)

2.00g of the polyimide solution (SPI-2) obtained in Synthesis example 2 and 8.11g of the polyamic acid solution (PAA-1) obtained in Synthesis example 4 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-2).

(example 3)

2.03g of the polyimide solution (SPI-3) obtained in Synthesis example 3 and 8.04g of the polyamic acid solution (PAA-1) obtained in Synthesis example 4 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-3).

(example 4)

5.43g of the polyimide solution (SPI-1) obtained in Synthesis example 1 and 5.41g of the polyamic acid solution (PAA-1) obtained in Synthesis example 4 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-4).

Comparative example 1

2.19g of the polyimide solution (SPI-4) obtained in Synthesis example 5 and 8.25g of the polyamic acid solution (PAA-1) obtained in Synthesis example 4 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (B-1).

Comparative example 2

2.07g of the polyimide solution (SPI-1) obtained in Synthesis example 1 and 9.39g of the polyamic acid solution (PAA-2) obtained in Synthesis example 6 were weighed in a50 mL Erlenmeyer flask equipped with a stirrer and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (B-2).

Comparative example 3

The polyimide solution (SPI-1) obtained in Synthesis example 1 was used as a liquid crystal aligning agent (B-3).

A method for manufacturing a liquid crystal cell for evaluating relaxation characteristics of accumulated charges, flicker characteristics, and liquid crystal alignment properties is described below.

A liquid crystal cell having a structure of an FFS liquid crystal display element was prepared. First, a substrate with electrodes is prepared. The substrate was a glass substrate having a size of 30mm × 35mm and a thickness of 0.7 mm. An IZO electrode as a 1 st layer constituting a counter electrode was formed on the entire surface of the substrate. A SiN (silicon nitride) film formed by a CVD method as a 2 nd layer was formed on the counter electrode of the 1 st layer. The SiN film of the 2 nd layer has a film thickness of 500nm and functions as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an IZO film as a 3 rd layer is disposed on the SiN film of the 2 nd layer, and two pixels, i.e., a 1 st pixel and a 2 nd pixel, are formed. The size of each pixel was 10mm in length and 5mm in width. At this time, the counter electrode of the 1 st layer and the pixel electrode of the 3 rd layer are electrically insulated by the SiN film of the 2 nd layer.

The pixel electrode of the layer 3 has a comb-tooth shape in which a plurality of く -shaped electrode elements each having a curved central portion are arranged. The width of each electrode element in the width direction was 3 μm, and the interval between the electrode elements was 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of く -shaped electrode elements bent at the central portion, the shape of each pixel is not rectangular, but has a shape similar to a "く" in a bold font bent at the central portion like the electrode elements. Each pixel is divided into upper and lower regions with a curved portion at the center as a boundary, and has a 1 st region on the upper side and a 2 nd region on the lower side of the curved portion.

When the 1 st region and the 2 nd region of each pixel are compared, the directions of formation of the electrode elements constituting the pixel electrodes are different. That is, when the brushing direction of the liquid crystal alignment film described later is set as a reference, the 1 st region of the pixel is formed so that the electrode element of the pixel electrode is at an angle of +10 ° (clockwise), and the 2 nd region of the pixel is formed so that the electrode element of the pixel electrode is at an angle of-10 ° (clockwise). That is, the 1 st region and the 2 nd region of each pixel are configured such that the directions of the rotational motion (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 opposite directions to each other.

The liquid crystal aligning agents obtained in examples and comparative examples were filtered through a filter having a pore size of 1.0 μm, and then applied to the prepared electrode-carrying substrate by spin coating. After drying on a hot plate at 80 ℃ for 2 minutes, the film was baked in a hot air circulation oven at 230 ℃ for 20 minutes to obtain a polyimide film having a film thickness of 60 nm. The polyimide film was brushed with a rayon cloth (roll diameter: 120mm, roll rotation speed: 500rpm, moving speed: 30 mm/sec, pressing length: 0.3mm, brushing direction: direction inclined at 10 ° to the 3 rd layer IZO comb electrode), and then, ultrasonic waves were irradiated in pure water for 1 minute to wash the film, and water droplets were removed by air blowing. Then, the substrate was dried at 80 ℃ for 15 minutes to obtain a substrate with a liquid crystal alignment film. Further, as the counter substrate, the following substrates with liquid crystal alignment films were obtained: a polyimide film was also formed on a glass substrate having an ITO electrode formed on the back surface and a columnar spacer having a height of 4 μm in the same manner as described above, and an alignment treatment was performed by the same procedure as described above. The 2 substrates with the liquid crystal alignment film were set as 1 group, and a sealant was printed so as to leave a liquid crystal injection port on the substrate, and the liquid crystal alignment film surfaces were opposed to each other and the brushing direction was antiparallel to each other, and the other substrate was attached. The sealant was then cured to produce an empty cell having a cell gap of 4 μm. Liquid crystal MLC-3019 (manufactured by Merck ltd) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS type liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 ℃ for 1 hour and placed at 23 ℃ for evaluation of liquid crystal alignment properties.

< relaxation characteristics of accumulated Charge >

The liquid crystal cell was disposed between 2 polarizing plates arranged so that the polarizing axes were orthogonal to each other, and the LED backlight was irradiated from below the 2 polarizing plates in a state where the pixel electrode and the counter electrode were short-circuited to the same potential, and the angle of the liquid crystal cell was adjusted so that the luminance of the LED backlight transmitted light measured on the 2 polarizing plates was the minimum.

Then, while applying a rectangular wave having a frequency of 30Hz to the liquid crystal cell, the V-T characteristics (voltage-transmittance characteristics) at a temperature of 23 ℃ were measured, and an AC voltage at which the relative transmittance reached 23% was calculated. Since the alternating voltage corresponds to a region where the luminance variation with respect to the voltage is large, it is convenient to evaluate the accumulated charges by the luminance.

Next, a rectangular wave having a frequency of 30Hz and an alternating voltage of 23% relative transmittance was applied at a temperature of 23 ℃ for 5 minutes, and then a direct voltage of +1.0V was superimposed and driven for 30 minutes. Then, the dc voltage was cut off, and only a rectangular wave having a frequency of 30Hz and an ac voltage of 23% relative transmittance was applied again for 30 minutes.

Since the faster the accumulated charge is relaxed, the faster the charge is accumulated in the liquid crystal cell when the dc voltage is applied, the relaxation characteristic of the accumulated charge is evaluated by the time required for the relative transmittance to decrease to 23% from a state in which the relative transmittance is 30% or more immediately after the dc voltage is applied. That is, when the relative transmittance decreased to 23% within 30 minutes, it was defined as "good", and when the relative transmittance did not decrease to 23% even after 30 minutes, it was defined as "bad".

< flicker characteristics >

Then, while applying a rectangular wave having a frequency of 30Hz to the liquid crystal cell, the V-T characteristics (voltage-transmittance characteristics) at a temperature of 23 ℃ were measured, and an AC voltage at which the relative transmittance reached 23% was calculated. Since the ac voltage corresponds to a region in which the luminance change with respect to the voltage is large, it is convenient to evaluate the flicker characteristic.

Next, the LED backlight turned on at a temperature of 23 ℃ was temporarily turned off, and after being left in the shade for 72 hours, the LED backlight was turned on again, an alternating voltage having a frequency of 30Hz and a relative transmittance of 23% was applied while the backlight was turned on, and the liquid crystal cell was driven for 30 minutes to follow the flicker amplitude. The flicker amplitude is read by a data collector/data logger conversion unit 34970a (manufactured by Agilent Technologies) connected via a photodiode and an I-V conversion amplifier by transmitting light of the LED backlight through 2 polarizing plates and the liquid crystal cell therebetween. The flicker level is calculated by the following mathematical formula.

Flicker level (%) { flicker amplitude/(2 × z) } × 100

In the above equation, z is a value read by the data collector/data logger converting unit 34970a for brightness when driven by an ac voltage having a frequency of 30Hz and a relative transmittance of 23%.

For the evaluation of the flicker characteristics, the evaluation was performed by defining the case where the flicker level was maintained at less than 3% as "good" and the case where the flicker level reached 3% or more in 30 minutes as "bad" from the time when the LED backlight was turned on and the ac voltage was applied until 30 minutes elapsed.

< evaluation of liquid Crystal alignment >

Using this liquid crystal cell, an AC voltage of 9VPP at a frequency of 30Hz was applied for 190 hours in a constant temperature environment of 60 ℃. Then, the liquid crystal cell was placed in a state in which the pixel electrode and the counter electrode were short-circuited at room temperature for one day.

After the placement, the liquid crystal cell was placed between 2 polarizing plates arranged so that the polarizing axes were orthogonal, the backlight was turned on in a state where no voltage was applied, and the arrangement angle of the liquid crystal cell was adjusted so that the brightness of transmitted light was minimum. Next, the rotation angle when the liquid crystal cell is rotated from the 2 nd area darkest angle to the 1 st area darkest angle of the 1 st pixel is calculated as an angle Δ. Similarly, in the 2 nd pixel, the 2 nd region and the 1 st region are compared, and the same angle Δ is calculated. Then, the average value of the angle Δ values of the 1 st pixel and the 2 nd pixel is calculated as the angle Δ of the liquid crystal cell. The liquid crystal cell was evaluated as "good" when the angle Δ was less than 0.4 degrees, and as "bad" when the angle Δ was 0.4 degrees or more.

(example 5)

The liquid crystal aligning agent (A-1) obtained in example 1 was filtered through a filter having a pore size of 1.0 μm, and then a liquid crystal cell was produced as described above. The relaxation characteristics of the accumulated charges were evaluated on the liquid crystal cell, and as a result, the time required for the relative transmittance to decrease to 23% was good at 8 minutes.

Next, the liquid crystal cell was evaluated for flicker characteristics, and as a result, the flicker level was 1% good. The liquid crystal cell was evaluated for liquid crystal alignment, and as a result, Δ was 0.21 degrees, which was good.

(example 6)

The relaxation characteristics of the accumulated charge were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (a-2) obtained in example 2 was used, and as a result, the time required for the relative transmittance to decrease to 23% was 4 minutes, which was good.

Next, the scintillation characteristics were evaluated in the same manner as in example 5, and the scintillation level was 1%, which was good. The liquid crystal alignment properties were evaluated in the same manner as in example 5, and the results showed that Δ was 0.06 degrees, which was good.

(example 7)

The relaxation characteristics of the accumulated charge were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (a-3) obtained in example 3 was used, and as a result, the time required for the relative transmittance to decrease to 23% was 4 minutes, which was good.

Next, the scintillation characteristics were evaluated in the same manner as in example 5, and the scintillation level was 1%, which was good. The liquid crystal alignment properties were evaluated in the same manner as in example 5, and as a result, Δ was 0.05 degrees, which was good.

(example 8)

The relaxation characteristics of the accumulated charge were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (a-4) obtained in example 4 was used, and as a result, the time required for the relative transmittance to decrease to 23% was good at 26 minutes.

Next, the scintillation characteristics were evaluated in the same manner as in example 5, and the scintillation level was 0.3%, which was good. The liquid crystal alignment properties were evaluated in the same manner as in example 5, and as a result, Δ was 0.22 degrees, which was good.

Comparative example 4

The relaxation characteristics of the accumulated charge were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (B-1) obtained in comparative example 1 was used, and as a result, the time required for the relative transmittance to decrease to 23% was good at 26 minutes.

Next, the scintillation characteristics were evaluated in the same manner as in example 5, and the scintillation level was found to be 2% good. In addition, the liquid crystal alignment properties were evaluated in the same manner as in example 5, and as a result, Δ was 0.63 degrees, which was poor.

Comparative example 5

The relaxation characteristics of the accumulated charge were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (B-2) obtained in comparative example 2 was used, and as a result, the time required for the relative transmittance to decrease to 23% was good at 24 minutes.

Next, the flicker characteristics were evaluated in the same manner as in example 5, and the flicker level was found to be 6% and defective. The liquid crystal alignment properties were evaluated in the same manner as in example 5, and as a result, Δ was 0.16 degrees, which was good.

Comparative example 6

The relaxation characteristics of accumulated charges were evaluated in the same manner as in example 5 except that the liquid crystal aligning agent (B-3) obtained in comparative example 3 was used, and as a result, the relative transmittance did not decrease to 23% even after 30 minutes had elapsed, which was poor.

Next, the scintillation characteristics were evaluated in the same manner as in example 5, and the scintillation level was 0.7%, which was good. The liquid crystal alignment properties were evaluated in the same manner as in example 5, and as a result, Δ was 0.11 degrees, which was good.

Table 1 shows the results of evaluation of relaxation characteristics of accumulated charge, flicker characteristics, and liquid crystal alignment properties when the liquid crystal alignment agents obtained in examples and comparative examples were used.

[ Table 1]

	Liquid crystal aligning agent	Relaxation characteristic of accumulated charge	Scintillation property Liquid crystal orientation
					Example 5	(A-1)	Good effect Good wine	Good taste	Good effect
Example 6	(A-2) Good wine	Good taste	Good effect	Good effect
					Example 7	(A-3)	Good effect	Good effect	Good effect
Example 8	(A-4)	Good effect	Good effect	Good effect
					Comparative example 4	(B-1)	Good effect	Good effect	Failure of the product
Comparative example 5	(B-2)	Good effect	Failure of the product	Good effect
					Comparative example 6	(B-3)	Failure of the product	Good effect	Good effect

Industrial applicability

The liquid crystal aligning agent of the present invention is widely used for liquid crystal display elements of longitudinal electric field systems such as TN system and VA system, and particularly for liquid crystal display elements of transverse electric field systems such as IPS system and FFS system.

The entire contents of the specification, claims, drawings and abstract of japanese patent application 2016-158014, filed 2016, 8/10/2016, are incorporated herein by reference, and the disclosure of the specification is incorporated herein as the present invention.

Claims

1. A liquid crystal aligning agent comprising a polymer (A) having a structure represented by the following formula (1) and a polymer (B) having a structure represented by the following formula (2),

wherein, in the formula (1), R¹Represents hydrogen or C1-3 alkyl, in formula (2), R²Is a single bond or a 2-valent organic radical, R³Is- (CH)₂)_n-structure (i) wherein n is an integer of 2 to 20, optionally-CH₂Optionally substituted, in the absence of adjacency to each other, by a bond selected from the group consisting of ether, ester, amide, urea and carbamate, the hydrogen atoms of the amide and urea being optionally substituted by methyl or tert-butoxycarbonyl, R⁴Is a single bond or a 2-valent organic group, any hydrogen atom on the benzene ring is optionally substituted by a 1-valent organic group,

wherein the content of the polymer (A) is 10 to 95% by mass and the content of the polymer (B) is 5 to 90% by mass, based on the total amount of the polymer (A) and the polymer (B).

3. The liquid crystal aligning agent according to claim 1, wherein the polymer (B) is at least 1 polymer selected from the group consisting of a polyimide precursor (B) which is a polycondensate of a diamine having a structure represented by the formula (2) and a tetracarboxylic dianhydride, and an imide thereof, i.e., a polyimide (B).

4. The liquid crystal aligning agent according to claim 2, wherein the polyimide precursor (A) has a structural unit represented by the following formula (3),

wherein, in the formula (3), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is derived fromA 2-valent organic radical of a diamine comprising the structure of formula (1), R¹⁰Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

5. The liquid crystal aligning agent according to claim 4, wherein in the formula (3), Y₁Represented by an arbitrary formula shown below,

6. the liquid crystal aligning agent according to claim 4 or 5, wherein the polymer having the structural unit represented by formula (3) is contained in an amount of 10 mol% or more based on the total polymer contained in the liquid crystal aligning agent.

7. The liquid crystal aligning agent according to claim 3, wherein the polyimide precursor (B) has a structural unit represented by the following formula (5),

8. The liquid crystal aligning agent according to any one of claims 1 to 5, which contains an organic solvent for dissolving the polymer (A) and the polymer (B).

9. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal display element comprising the liquid crystal alignment film according to claim 9.

11. The liquid crystal display element according to claim 10, wherein the liquid crystal display element is of a lateral electric field driving type.

12. The liquid crystal display element according to claim 10 or 11, wherein the liquid crystal display element is of an FFS type.