CN110036337B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element using same - Google Patents

Abstract

Provided are a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element, which are capable of obtaining a liquid crystal alignment film that has excellent voltage holding ratio, that rapidly relaxes accumulated charges, and that is less likely to flicker during driving. A liquid crystal aligning agent characterized by containing a polymer obtained from a diamine having a structure represented by the following formula (1) and an organic solvent. (R)¹、R²Is a hydrogen atom or a 1-valent organic group. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group. Indicates the bonding site)

Description

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

Technical Field

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

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 longitudinal 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 the lateral electric field system has wider viewing angle characteristics than a conventional vertical electric field system in which a voltage is applied to electrodes formed on upper and lower substrates to drive liquid crystal, and is known as a liquid crystal display element capable of high-quality display.

Although the liquid crystal cell of the lateral electric field method is excellent in viewing angle characteristics, since the number of electrode portions formed in the substrate is small, if the voltage holding ratio is low, a sufficient voltage is not applied to the liquid crystal, and the display contrast is lowered. In addition, 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 electric charges are also accumulated in the liquid crystal cell by the application of positive and negative asymmetric voltages generated by driving, and the accumulated electric charges affect display in the form of disturbance of liquid crystal alignment or afterimage, thereby significantly reducing the display quality of the liquid crystal element. In addition, the backlight irradiation to the liquid crystal cell immediately after the driving also causes charge accumulation, and afterimages may be generated even in a short-time driving; the size of flicker (flicker) in driving, and the like.

As a liquid crystal aligning agent which is excellent in voltage holding ratio and reduces charge accumulation when used in such a liquid crystal display device of the transverse electric field system, patent document 1 discloses a liquid crystal aligning agent containing a specific diamine and an aliphatic tetracarboxylic acid derivative. 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 WO2004/021076 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 can be simultaneously improved by introducing a specific structure into a polymer contained in a liquid crystal aligning agent, thereby completing the present invention.

The present invention has been completed based on this finding, and the gist thereof is as follows.

1. A liquid crystal aligning agent characterized by containing a polymer obtained from a diamine having a structure represented by the following formula (1) and an organic solvent.

(in the formula (1), R¹、R²Is a hydrogen atom or a 1-valent organic group. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group. Denotes the bonding site. )

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

3. The liquid crystal aligning agent according to the foregoing 1 or 2, wherein the diamine is represented by the following formula (2).

(in the formula (2), R¹And R²Is as defined for the above formula (1), R³Each independently represents a single bond or a structure of the following formula (3), and n represents an integer of 1 to 3. Benzene ringOptionally substituted with a 1-valent organic group. )

(in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-, and-NHCO-, (l and m each represents an integer of 1 to 5)₁Represents a site bonded to the benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2). )

4. The liquid crystal aligning agent according to any one of the preceding claims 1 to 3, wherein the polyimide precursor has a structure represented by the following formula (4).

(in the formula (4), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic group derived from a diamine represented by the formula (1), R₅Is 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 (6), X₁Is at least 1 selected from the group consisting of the following structures (A-1) to (A-21).

6. The liquid crystal aligning agent according to the above 4 or 5, wherein the polymer having the structural unit represented by the above formula (4) 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 any one of claims 1 to 6, wherein the organic solvent contains at least 1 selected from the group consisting of 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether.

8. A liquid crystal alignment film obtained by using the liquid crystal alignment agent according to any one of the above 1 to 7.

9. A liquid crystal display element comprising the liquid crystal alignment film according to 8.

10. The liquid crystal display element according to claim 9, wherein the liquid crystal display element is a lateral electric field driving type.

11. A polymer which is at least 1 selected from the group consisting of polyimide precursors and imides thereof, namely, polyimide, wherein the polyimide precursors are polycondensates of diamines and tetracarboxylic dianhydrides having a structure represented by the following formula (1).

(in the formula (1), R¹、R²Is a hydrogen atom or a 1-valent organic group. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group. Denotes a bonding site. )

12. The polymer according to claim 11, wherein the diamine is represented by the following formula (2).

(in the formula (2), R¹And R²Is as defined for the above formula (1), R³Each independently has a single bond or a structure represented by the following formula (3), and n represents an integer of 1 to 3. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group. )

(in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-and-NHCO-, (l and m each represents an integer of 1 to 5)₁Represents a site bonded to the benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2). )

(in the formula (4), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic group derived from a diamine represented by the formula (1), R₅Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. )

14. The polymer according to the foregoing 13, wherein, in the formula (6), X₁Is at least 1 selected from the group consisting of the following structures (A-1) to (A-21).

15. A diamine represented by the following formula (2).

(in the formula (2), R¹And R²Is as defined for the above formula (1), R³Each independently has a single bond or a structure represented by the following formula (3), and n represents an integer of 1 to 3. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group. )

ADVANTAGEOUS EFFECTS OF INVENTION

By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film in which relaxation of accumulated charge is fast and flicker (flicker) is less likely to occur during driving, and a liquid crystal display element excellent in display characteristics can be provided.

The reason why the above-described technical problems can be solved by the present invention is not clear, but is generally considered as follows. It is considered that since the diamine represented by the above (1) contained in the polymer contained in the liquid crystal aligning agent of the present invention has a structure in which a conductive pyrrole ring is conjugated to a benzene ring, when a liquid crystal alignment film formed from the liquid crystal aligning agent is used, electric charges applied during driving of an element are easily moved, and relaxation of accumulated electric charges can be promoted.

Detailed Description

< specific diamine >

The liquid crystal aligning agent of the present invention contains a polymer obtained from a diamine having a structure represented by the following formula (1) (also referred to as a specific diamine in the present invention).

In the above formula (1), R¹、R²Is as defined above. Wherein R is¹、R²The alkyl group, alkenyl group, alkoxy group, fluoroalkyl group, fluoroalkenyl group or fluoroalkoxy group having 1 to 3 carbon atoms is preferable, and a hydrogen atom or a methyl group is particularly preferable. In addition, a represents a site bonded to an amino group, a substituted amino group, another organic group, or the like.

Among the specific diamines, as shown in the following formula (1-1), the bonding positions of 2 benzene rings to the pyrrole ring, at least one of which is preferably bonded to a carbon atom located beside the nitrogen atom on the pyrrole ring, from the viewpoint of charge transfer.

The specific diamine can be represented by, for example, the following formula (1-2), particularly preferably a diamine represented by the following formula (1-3), and still more preferably a diamine represented by the following formula (1-4). In these chemical formulae, a represents a bonding site.

In the formulae (1-2) to (1-4), R¹And R²Is as defined in said formula (1), Q¹、Q²Each independently being a single bond or a 2-valent organic group, i.e. Q¹And Q²May be of different construction from one another. In addition, 2 Qs in the formula (1-4)²May be of different construction from one another. And, as in the above formula (1), any hydrogen atom of the benzene ring is optionally substituted with a 1-valent organic group.

Preferable examples of the specific diamine include diamines represented by the following formula (2), and more preferably diamines represented by the formula (2-1).

In the formula (2), R¹And R²Is as defined for formula (1) above, R³Each independently represents a single bond or a structure of the following formula (3), and n represents an integer of 1 to 3. Any hydrogen atom of the phenyl ring is optionally substituted with a 1-valent organic group.

(in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-and-NHCO-, (l and m each represents an integer of 1 to 5)₁Represents a site bonded to the benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2). )

In the formulas (2) and (2-1), n represents an integer of 1 to 3. Preferably 1 or 2.

Specific examples of the diamine of the formula (2) include, but are not limited to, the following. Among them, (2-1-1), (2-1-2), (2-1-3), (2-1-4), (2-1-5), (2-1-8), (2-1-9), (2-1-10), (2-1-11) or (2-1-12) are preferable from the viewpoint of relaxation of the accumulated charge, and (2-1-1), (2-1-2), (2-1-3), (2-1-4), (2-1-5), (2-1-11) or (2-1-12) is particularly preferable.

< Synthesis method of specific diamine >

The method for synthesizing the specific diamine of the present invention is not particularly limited, and examples thereof include a method for synthesizing a dinitro compound represented by the following formula (1) and further reducing and converting the nitro group into an amino group.

(R₁、R₂And R₃Represents hydrogen or a 1-valent organic group. )

The catalyst used in the reduction reaction is preferably a commercially available activated carbon-supported metal, and examples thereof include palladium-activated carbon, platinum-activated carbon, rhodium-activated carbon, and the like. The catalyst may be palladium hydroxide, platinum oxide, raney nickel, or the like, and is not necessarily an activated carbon-supported metal catalyst. In particular, palladium-activated carbon is preferable because good results can be obtained.

In order to more efficiently perform the reduction reaction, the reaction may be performed in the presence of activated carbon. In this case, the amount of the activated carbon to be used is not particularly limited, but is preferably in the range of 1 to 30% by mass, more preferably 10 to 20% by mass, based on the dinitro compound. For the same reason, the reaction may be carried out under pressure. In this case, in order to avoid reduction of the benzene nucleus, it is preferably carried out in a pressurized range of at most 20 atmospheres, and more preferably in a pressurized range of at most 10 atmospheres.

The solvent may be used without limitation as long as it does not react with each raw material. For example, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.); ethers (Et)₂O、i-Pr₂O, TBME, CPME, THF, dioxane, etc.); aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); halogen-based hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.) and the like. These solvents may be appropriately selected in consideration of the ease of reaction, and 2 or more of them may be used in combination. The solvent may be dried using a suitable dehydrating agent or drying agent as needed, and used as a nonaqueous solvent.

The amount of the solvent used (reaction concentration) is preferably 0.1 to 10 times by mass, more preferably 0.5 to 30 times by mass, and particularly preferably 1 to 10 times by mass, relative to the dinitro compound. The reaction temperature is not particularly limited, and is in the range from-100 ℃ to the boiling point of the solvent used, preferably-50 to 150 ℃. The reaction time is usually 0.05 to 350 hours, preferably 0.5 to 100 hours.

On the other hand, the method for synthesizing the nitro compound (A-1) is not particularly limited, and when the positions of substitution of the amino group in the compound (A-1) are 2-position and 4-position, the nitro compound can be obtained by, for example, reacting a diamine represented by the following formula (A-2) with a halogenated aryl group having a nitro group in the presence of a base and, if necessary, an additive (X represents F, Cl, Br, I or OTf.)

In the above halogenated aryl groups having a nitro group, if X is F or Cl, and NO₂When the group is in the 2-or 4-position with respect to X, the halogenated aryl group may be reacted with an aliphatic amine compound in the presence of a base to obtain compound (A-1). Examples of the base to be used include inorganic bases such as sodium hydrogen carbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate, amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diisopropylethylamine, pyridine, quinoline, and collidine, and sodium hydride and potassium hydride. The reaction solvent and the reaction temperature are as described above. The product can be purified by recrystallization, distillation, silica gel column chromatography, etc.

If X is Br or I, NO₂The group may be 2-, 3-or 4-position with respect to X, and a dinitrate matrix may also be obtained by C-N cross-coupling reaction in the presence of a suitable metal catalyst, ligand, and base. Examples of the metal catalyst include, but are not limited to, palladium acetate, palladium chloride-acetonitrile complex, palladium-activated carbon, bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, bis (acetonitrile) dichloropalladium, bis (benzonitrile) dichloropalladium, CuCl, CuBr, CuI, CuCN, and the like. Examples of the ligand include triphenylphosphine, tri (o-tolyl) phosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1, 2-bis (diphenylphosphino) ethane, 1, 3-bis (diphenylphosphino) propane, 1, 4-bis (diphenylphosphino) butane, 1' -bis (diphenylphosphino) ferrocene, trimethyl phosphite, dimethyl phosphite, and the like,Triethyl phosphite, triphenyl phosphite, tri-t-butyl phosphine, and the like, but are not limited thereto. As an example of the base, the bases mentioned above can be used. The reaction solvent and the reaction temperature were as described above. The product can be purified by recrystallization, distillation, silica gel column chromatography, etc.

The method for synthesizing the compound (A-2) is not particularly limited, and examples thereof include the synthesis of a diamine represented by the following formula (A-3), and the reaction with NH₂Introduction of R into₁、R₃The method of (1).

Introduction of R₁、R₃In the case of the above-mentioned amine-based compound, any compound capable of reacting with an amine may be used, and examples thereof include acid halides, acid anhydrides, isocyanates, epoxies, oxetanes, halogenated aryls, and halogenated alkanes. In addition, alcohols in which the hydroxyl group of the alcohol is substituted with a leaving group such as OMs, OTf, OTs, and the like can be used.

At NH₂Introduction of radicals from R₁、R₃The method of forming the 1-valent organic group is not particularly limited, and examples thereof include a method of reacting an acid halide in the presence of a suitable base. Examples of the acid halide include acetyl chloride, propionyl chloride, methyl chloroformate, ethyl chloroformate, n-propyl chloroformate, isopropyl chloroformate, n-butyl chloroformate, isobutyl chloroformate, tert-butyl chloroformate, benzyl chloroformate, and 9-fluorene chloroformate. As an example of the base, the bases mentioned above can be used. The reaction solvent and the reaction temperature are as described above.

May also be NH₂By reaction of radicals with anhydrides to introduce R₁、R₃. Examples of the acid anhydride include acetic anhydride, propionic anhydride, dimethyl dicarbonate, diethyl dicarbonate, di-t-butyl dicarbonate, and dibenzyl dicarbonate. A catalyst may be used to accelerate the reaction, and pyridine, collidine, N-dimethyl-4-aminopyridine, etc. may be used. The amount of the catalyst is preferably 0.0001 to 1 mole based on the amount of (A-3). Reaction solvent, reaction temperatureThe degree of the above-mentioned compounds is in accordance with the above-mentioned description.

May also be NH₂By reaction of radicals with isocyanates to introduce R₁. Examples of the isocyanates include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and phenyl isocyanate. The reaction solvent and the reaction temperature are as described above.

May also be NH₂By reaction of radicals with epoxy compounds, oxetane compounds, to introduce R₁、R₃. Examples of the epoxy and oxetane compounds include ethylene oxide, propylene oxide, 1, 2-butylene oxide, and oxetane. The reaction solvent and the reaction temperature are as described above.

May also be NH₂The group is reacted with an alcohol having a hydroxyl group of the alcohol substituted with a leaving group such as OMs, OTf, OTs or the like in the presence of a suitable base to introduce R₁、R₃. Examples of the alcohol include methanol, ethanol, and 1-propanol, and these alcohols are reacted with methanesulfonyl chloride, trifluoromethanesulfonyl chloride, and p-toluenesulfonyl chloride to obtain an alcohol substituted with a leaving group such as OMs, OTf, and OTs. As examples of the base, the bases mentioned above can be used. The reaction solvent and the reaction temperature are as described above.

May also be NH₂By reaction of radicals with alkyl halides in the presence of a suitable base to introduce R₁、R₃. Examples of the alkyl halide include methyl iodide, ethyl iodide, n-propyl iodide, methyl bromide, ethyl bromide, and n-propyl bromide. As examples of the base, metal alkoxides such as potassium tert-butoxide and sodium tert-butoxide can be used in addition to the above-mentioned bases. The reaction solvent and the reaction temperature are as described above.

Further, the method for synthesizing the compound (a-3) is not particularly limited, and a method of synthesizing a nitro compound represented by the following formula (4) and further reducing and converting the nitro group of the nitro compound into an amino group can be exemplified.

The catalyst, solvent and temperature used in the reaction are as described above.

The method for synthesizing the compound (a-4) is not particularly limited, and it can be synthesized by subjecting a1, 4-diketone compound (a-5) represented by the following formula (5) and a primary amine to dehydration condensation under acidic conditions.

Examples of the acid used in this reaction include, but are not limited to, acetic acid, p-toluenesulfonic acid, pyridinium p-toluenesulfonate, and the like. The reaction solvent and the reaction temperature are as described above.

Further, the method for synthesizing the compound (a-5) is not particularly limited, and can be obtained by reacting an α -haloketone having a nitro group represented by the following formula (6) with a ketone having a nitro group in the presence of a base.

(X represents Br, I or OTf.)

As an example of the base used in this reaction, the bases mentioned above can be used. The reaction solvent and the reaction temperature are as described above. Additives may be used in order to accelerate the reaction rate. As the additive, zinc chloride, sodium iodide, potassium iodide, tetrabutylammonium iodide, and the like can be used, but not limited thereto.

< specific Polymer >

The polymer of the present invention is a polymer obtained by using the above-mentioned specific diamine. Specific examples thereof include polyamic acids, polyamic acid esters, polyimides, polyureas, and polyamides. Among them, from the viewpoint of use as a liquid crystal aligning agent, at least 1 polymer (hereinafter, also referred to as a specific polymer) selected from a polyimide precursor containing a structural unit represented by the following formula (4) and a polyimide which is an imide compound thereof is more preferable.

In the above formula (4), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic group derived from a particular diamine. R is₅Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R is R from the viewpoint of ease of imidation by heating₅Preferably a hydrogen atom, a methyl group or an ethyl group.

X is above₁The number of the polymer to be used is appropriately selected depending on the degree of the desired properties such as solubility in a solvent, coating properties of a liquid crystal aligning agent, alignment properties of liquid crystal when a liquid crystal alignment film is formed, a voltage holding ratio, and a cumulative charge, and 2 or more species of the polymer may be used.

If X is enumerated₁Specific examples of (4) include structures of formulae (X-1) to (X-46) described in International patent application publication No. 2015/119168, pages 13 to 14.

X is shown below as preferred₁The above (A-1) to (A-21) are not limited thereto.

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

< other structural units >

The polyimide precursor may have a structural unit represented by the following formula (5) in addition to the structural unit represented by the formula (4).

In the formula (5), X₂Is the same as defined in said formula (4). As X₂Specific examples of (3) include preferable examples of X in the formula (4)₁Examples of which are listed above. R₄Are all as defined in said formula (4). Preferably 2R₄At least one of which is a hydrogen atom.

In addition, Y₂The organic group is a 2-valent organic group derived from a diamine not containing the structure represented by the above formula (1) in the main chain direction, and the structure thereof is not particularly limited. Y is₂The polymer may be appropriately selected depending on the degree of the desired properties such as solubility in a solvent, coatability of a liquid crystal aligning agent, alignment of liquid crystal when a liquid crystal alignment film is formed, voltage holding ratio, and accumulated charge, and 2 or more kinds of the polymer may be mixed in the same polymer

If Y is enumerated₂Specific examples of (3) include the structure of the formula (2) described in International laid-open publication No. 2015/119168 on page 4, and the structures of the 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) as described in international publication No. 2013/008906, page 6; a 2-valent organic group obtained by removing 2 amino groups from the formula (1) as described in international publication No. 2015/122413, page 8; a structure of formula (3) described in page 8 of International publication No. 2015/060360; 2-valent organic groups obtained by removing 2 amino groups from the formula (1) as described in Japanese laid-open patent publication No. 2012-173514 page 8; a 2-valent organic group obtained by removing 2 amino groups from the formulae (A) to (F) described in International publication No. 2010-050523 on page 9, and the like.

Preferred Y is shown below₂The present invention is not limited thereto.

In the above-mentioned structure, (B-28), (B-29) and the like are particularly preferable from the viewpoint of further improving the rubbing resistance, and (B-1) to (B-3) and the like are particularly preferable from the viewpoint of further improving the liquid crystal alignment property, and (B-14) to (B-18) and (B-27) are particularly preferable from the viewpoint of further improving the relaxation rate of the accumulated charge, and (B-26) and the like are preferable from the viewpoint of further improving the voltage holding ratio.

When the polyimide precursor contains a structural unit represented by formula (5) in addition to the structural unit represented by formula (4), the structural unit represented by formula (4) is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more, based on the total amount of formula (4) and formula (5).

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.

< polyimide >

The polyimide in the specific polymer is obtained by ring-closing a polyimide precursor represented by formula (4) or formula (5). The imidization ratio in this case is not necessarily 100%, and can be arbitrarily adjusted depending on the application and the purpose.

As a method for imidizing the polyimide precursor, a known method can be used. Chemical imidization by adding a basic catalyst to a polyimide precursor solution 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.

The chemical imidization can be performed by stirring a polyimide precursor in an organic solvent in the presence of a basic catalyst. 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, triethylamine is preferable because it has a sufficient basicity for the reaction to proceed.

The temperature for the imidization is-20 to 140 ℃ and preferably 0 to 100 ℃, and the reaction time is preferably 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amount of the amide ester group. The imidization ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, reaction time, and the like.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyimide precursor, 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.

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

The liquid crystal aligning agent of the present invention contains a specific polymer, and may contain 2 or more specific polymers having different structures within limits to exhibit the effects of the present invention. In addition, other polymers may be contained in addition to the specific 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. Further, the polyimide may contain a polyimide precursor represented by the above formula (5), a polyimide selected from polyimides obtained by imidizing the polyimide precursor, and the like.

When the liquid crystal aligning agent of the present invention contains another polymer, the proportion of the specific polymer to the whole polymer component is preferably 5% by mass or more, and more preferably 5 to 95% by mass.

The liquid crystal aligning agent is used for producing a liquid crystal alignment film, and is generally 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 also preferably a coating solution containing the above-mentioned polymer component and an organic solvent capable of dissolving the polymer component. In this case, the concentration of the polymer in the liquid crystal aligning agent may be appropriately changed according to the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. 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 an organic 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, and cyclopentanone. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone is preferable.

In addition, as the organic solvent contained in the liquid crystal aligning agent, a mixed solvent in which a solvent capable of improving coatability when the liquid crystal aligning agent is coated and surface smoothness of a coating film are used in combination with the above-mentioned solvent is generally used, and such a mixed solvent is preferably used in 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, 1, 2-ethanediol, 1, 2-propanediol, isobutanol, 2-pentanol, 2-methyl-1-pentanol, 1-methyl-1-heptanol, 2-1-methyl-1-hexanol, 2-cyclohexanol, 2-propanediol, 2-butanol, and mixtures thereof, 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, 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, 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 monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monohexyl ether, propylene glycol, ethylene glycol, propylene glycol, ethylene glycol, propylene glycol, ethylene glycol, and propylene glycol, and propylene glycol, and propylene glycol, and propylene glycol mono-ethylene glycol mono-ethyl 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, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, propyl 3-methoxypropionate, 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], and the like.

Formula [ D-1]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-2]In (D)²Represents an alkyl group having 1 to 3 carbon atoms, formula [ D-3]]In (D)³Represents an alkyl group having 1 to 4 carbon atoms. Of these, 1-hexanol, cyclohexanol, 1, 2-ethylene glycol, 1, 2-propylene glycol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, or dipropylene glycol dimethyl ether are preferable. The kind and content of such a solvent can be 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 adhesion promoters 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 crosslinking agent for improving the strength of the liquid crystal alignment film; a dielectric or conductive material for adjusting the dielectric constant or resistance of the liquid crystal alignment film. Specific examples of such additional components include those disclosed in the publicly known documents relating to liquid crystal aligning agents, for example, International patent publication No. 2015/060357, page 53, paragraph [0105] to page 55, paragraph [0116], if one is mentioned.

< liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is obtained from the liquid crystal aligning agent of the present invention. 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 baked to obtain a film, and the film is subjected to an alignment treatment by a brushing treatment method or a photo-alignment treatment method.

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, from the viewpoint of process simplification. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used as long as it is a single-sided substrate, and a material that reflects light such as aluminum may be used as the electrode 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 a heating means such as a hot plate, a thermal cycle oven, or an IR (infrared ray) 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, and 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 formed 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 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. Note that the liquid crystal display element may be an active matrix liquid crystal display element in which a conversion element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting 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, for example, ITO electrodes, and are patterned so as to be able to achieve the desired resultAnd displaying the viewed image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film may be formed of, for example, SiO 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 the two substrates on which the liquid crystal alignment films are formed, and further, liquid crystal is disposed at several predetermined positions on the liquid crystal alignment film surface, and then, the other substrate is bonded and pressure-bonded so that the liquid crystal alignment films face each other, whereby the liquid crystal is spread over the entire surface of the liquid crystal alignment film, and then, the sealing material is cured by irradiating ultraviolet rays onto the entire surface of the substrate, thereby obtaining 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. Subsequently, a polarizing plate was disposed. 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 alignment film and the liquid crystal display element of the present invention are not limited to the above description as long as the liquid crystal alignment agent of the present invention is used, and can be produced by other known methods. For example, Japanese patent laid-open publication No. 2015-135393 discloses steps up to obtaining a liquid crystal display element from a liquid crystal aligning agent, such as paragraph 17, 0074 to paragraph 19, 0081.

Examples

The present invention will be specifically described below by way of examples and the like. It should be noted that the present invention is not limited to these examples.

The following raw material abbreviations and characteristic evaluation methods are as follows.

< organic solvent >

NMP: n-methyl-2-pyrrolidone,

NEP: n-ethyl-2-pyrrolidone

GBL: γ -butyrolactone, BCS: butyl cellosolve

PB: propylene glycol monobutyl ether

DME: dipropylene glycol dimethyl ether

DAA: 4-hydroxy-4-methyl-2-pentanone

DEDG: diethylene glycol diethyl ether

And (3) DIBK: 2, 6-dimethyl-4-heptanone,

DIPE: diisopropyl ether,

DIBC: 2, 6-dimethyl-4-heptanol,

Pd/C: palladium on carbon,

DMSO, DMSO: dimethyl sulfoxide, THF: tetrahydrofuran (THF)

< additive >

LS-4668: 3-glycidoxypropyltriethoxysilane

< crosslinking agent >

In the specification, Boc and Fmoc represent groups shown below, and Me represents a methyl group.

(¹Measurement of H-NMR

The device comprises the following steps: varian NMR system 400NB (400MHz, manufactured by Varian corporation) and JMTC-500/54/SS (500MHz, manufactured by JEOL corporation)

And (3) measuring a solvent: CDCl₃(deuterated chloroform), DMSO-d₆(deuterated dimethyl sulfoxide)

Reference substance: TMS (tetramethylsilane) (δ: 0.0ppm,¹H) and CDCl₃(δ：77.0ppm，¹³C)

(measurement of imidization ratio)

20mg of the polyimide powder was put into an NMR sample tube (. phi.5 (manufactured by Softweed scientific Co.), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53ml) was added thereto, followed by ultrasonic wave treatment to completely dissolve the polyimide powder. 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 cumulative value of a proton derived from an NH group of amic acid, y represents a peak cumulative 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 of diamine Compound (DA-1) >

Zinc chloride (120.3g, 882mmol) was added to a 3L (liter) four-necked flask, the temperature was raised to 100 ℃ and vacuum-dried for 1 hour by means of an oil pump. Then, toluene (460g), diethylamine (45.0g, 615mmol), tert-butanol (46.4g, 626mmol), 2-bromo-4-nitroacetophenone (100.0g, 410mmol) and 4-nitroacetophenone (104.2g, 631mmol) were added in this order at room temperature under a nitrogen atmosphere, and the mixture was stirred at room temperature for 3 days. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), a 5% aqueous solution (400g) of sulfuric acid was added to neutralize the reaction solution, and the mixture was stirred at room temperature for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with toluene (200g), pure water (300g) and methanol (200g) in this order, and then dried to obtain crude crystals. After the obtained crude crystals were completely dissolved in tetrahydrofuran (1340g) at 60 ℃, ethanol (1340g) was added and stirred at 5 ℃ for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with ethanol (200g), and dried to obtain powdery crystals (1) (yield 63g, 45%).

1H-NMR(DMSO-d₆)：8.40-8.36(4H，m)，8.28-8.24(4H，m)，3.53(4H，s)

Compound (1) (65.8g, 200mmol), ammonium acetate (84.5g,1100mmol) and acetic acid (855g) were charged into a 2L four-necked flask, and the mixture was heated to 120 ℃ and stirred under reflux for 3 hours. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the reaction mixture was added to cold water (4000g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with acetonitrile (100g) again, and dried to obtain powdery crystals (2) (yield 53g, yield 78%).

1H-NMR(DMSO-d₆)：11.8(1H，br)，8.30-8.26(4H，m)，8.11-8.07(4H，m)，7.04(2H，s)

Compound (2) (41.3g, 134mmol), potassium carbonate (27.8g, 201mmol) and dimethylformamide (540g) were charged in a 1L four-necked flask, and methyl iodide (38.1g, 268mmol) was added dropwise at room temperature, followed by stirring for 24 hours. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the reaction mixture was added to cold water (4300g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100g), and dried to obtain powdery crystals (3) (yield 41.1g, yield 90%).

1H-NMR(DMSO-d₆)：8.34-8.33(4H，m)，7.86-7.81(4H，m)，6.67(2H，s)，3.73(3H，s)

A mixture of the compound (3) (40g, 124mmol), 5 mass% Pd/C (50% aqueous form), special-grade egret activated carbon (4.0g), and dioxane (400g) was stirred at 80 ℃ for 8 hours under hydrogen pressure. After the reaction was completed, the catalyst was filtered, then concentrated, and 2-propanol (400g) was added thereto and stirred at 5 ℃ for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100g), and dried to obtain powdery crystals (4) (yield 17g, yield 52%).

1H-NMR(DMSO-d₆)：7.11-7.08(4H，m)，6.63-6.59(4H，m)，5.96(2H，s)，5.15(4H，s)，3.43(3H，s)

Compound (4) (27.4g, 104mmol) and THF (270g) were charged in a 1L four-necked flask, and trifluoroacetic anhydride (46.5g,220mmol) was added dropwise under ice-cooling, followed by stirring for 1 hour. After completion of the reaction, HPLC (high performance liquid chromatography) was used to confirm that the reaction was completed, the reaction mixture was concentrated, dried and solidified. To the resulting solid were added THF (600g) and potassium carbonate (45.1g, 326mmol), and methyl iodide (45.8g, 324mmol) was added dropwise at room temperature, followed by stirring at 40 ℃ for 22 hours. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the salt was removed by filtration under reduced pressure, concentrated, dried and solidified.

To the resulting solid were added N-methylpyrrolidone (200g), pure water (30g) and potassium hydroxide (20.8g,315mmol), and the mixture was stirred at 60 ℃ for 30 minutes. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the reaction mixture was added to cold water (1200g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100g), and dried to obtain powdery crystals (5) (yield 22.9g, yield 76%).

1H-NMR(DMSO-d₆)：7.20-7.17(4H，m)，6.60-6.57(4H，m)，5.99(2H，s)，5.73(2H，q)，3.45(3H，s)，2.70(6H，d)

Sodium hydride (19.7g,494mmol) and N-methylpyrrolidone (20g) were charged in a 1L four-necked flask, and ice-cooling was performed. A solution of compound (5) (22.9g,78.7mmol) and N-methylpyrrolidone (115g) was slowly dropped thereinto under a nitrogen stream, followed by dropping a solution of 4-fluoronitrobenzene (44.4g, 315mmol) and N-methylpyrrolidone (44g), and stirring was carried out at room temperature for 24 hours.

After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the reaction mixture was added to cold water (1800g) and stirred for 1 hour. The obtained crude crystals were reslurried and washed with tetrahydrofuran (450g), then filtered under reduced pressure, washed with methanol (100g), and dried to obtain powdery crystals (6) (yield 22.7g, yield 54%).

1H-NMR(DMSO-d₆)：8.09(4H，d)，7.64(4H，d)，7.42(4H，d)，6.87(4H，d)，6.37(2H，s)，3.69(3H，s)，3.44(6H，s)，

A mixture of compound (6) (22.7g, 42.6mmol), 5 mass% Pd/C (50% aqueous form), intrinsic white activated carbon (2.0g), and dioxane (230g) was stirred at 80 ℃ for 8 hours under hydrogen pressure. After the reaction was completed, the catalyst was filtered, then concentrated, and 2-propanol (300g) was added thereto and stirred at 5 ℃ for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100g), and dried to obtain powdery crystals (DA-1) (yield 17.4g, yield 86%).

1H-NMR(DMSO-d₆)：7.20(4H，d)，6.89(4H，d)，6.67-6.59(8H，m)，6.02(2H，s)，5.06(4H，s)，3.46(3H，s)，3.17(6H，s)，

[ Synthesis example 1]

After DA-1(1.99g, 4.2mmol) was charged in a 100ml four-necked flask with a stirring device and a nitrogen introduction tube, NMP: GBL ═ 1: 1 (mass ratio) of 20.0g of the mixed solvent was dissolved by stirring while feeding nitrogen gas. While stirring the solution, CA-1(0.61g, 2.8mmol), CA-2(0.73g, 3.7mmol), and NMP: GBL ═ 1: 1 was mixed with 8.0g of a solvent, and the mixture was further stirred at 50 ℃ for 12 hours, thereby obtaining a polyamic acid solution (PAA-A1).

[ Synthesis examples 2 to 6]

A polyamic acid solution (PAA-A2) and polyamic acid solutions (PAA-B1) to (PAA-B4) were obtained in the same manner as in Synthesis example 1, except that the diamine component, the tetracarboxylic acid component, and the solvent shown in Table 1 were used.

[ Table 1]

[ Synthesis example 7]

DA-6(4.03g, 16.5mmol), DA-7(3.59g, 9.0mmol) and DA-8(2.51g, 4.5mmol) were charged into a 200ml four-necked flask equipped with a stirrer and a nitrogen inlet, and then NMP74.0g was added thereto, and the mixture was dissolved by stirring while feeding nitrogen. While stirring the solution, CA-4(4.37g, 19.5mmol) and NMP9.0g were added, and the mixture was stirred at 40 ℃ for 3 hours. Thereafter, CA-2(1.71g, 8.7mmol) and NMP9.0g were added thereto at 25 ℃ and the mixture was stirred for another 12 hours to obtain a polyamic acid solution.

80.0g of the polyamic acid solution was divided, 20.0g of NMP20 was added, and then 6.8g of acetic anhydride and 1.8g of pyridine were added to the solution to react at 50 ℃ for 3 hours. The reaction solution was poured into 434.4g of methanol with stirring, and the precipitated precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder. The imidization rate of this polyimide was 75%. To 20.0g of the obtained polyimide powder, 80.0g of NMP80 was added, and the mixture was stirred at 70 ℃ for 20 hours to dissolve the powder, thereby obtaining a polyimide solution (SPI-B5).

[ Synthesis example 8]

DA-5(68.5g,280mmol) and DA-8(23.9g,70mmol) were measured in a 1000mL four-necked flask equipped with a stirrer and a nitrogen inlet, and dissolved by adding 586g of NMP and stirring while feeding nitrogen. While stirring the solution, CA-4(74.5g,332mmol) was added, and NMP was further added so that the solid content concentration became 18 mass%, and the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution.

200g of the polyamic acid solution was weighed, 100g of NMP was added thereto, and the mixture was stirred for 30 minutes. To the polyamic acid solution thus obtained were added 21.78g of acetic anhydride and 2.81g of pyridine, and the mixture was reacted at 60 ℃ for 3 hours. The obtained reaction solution was poured into 624.2g of methanol while stirring, and the precipitated precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain a polyimide powder. The imidization rate of this polyimide was 68%. NMP 239.8g was added to 32.7g of the obtained polyimide powder, and the mixture was stirred at 70 ℃ for 20 hours to dissolve the powder, thereby obtaining a polyimide solution (SPI-B6).

Examples 1 to 12 and comparative examples 1 to 7

The polyamic acid solutions obtained in synthesis examples 1 to 6 and the polyimide solutions obtained in synthesis examples 7 and 8 were stirred while adding a solvent and an additive so as to have the compositions shown in tables 2 and 3, respectively, and further stirred at room temperature for 2 hours, thereby obtaining liquid crystal aligning agents of examples 1 to 12 and comparative examples 1 to 7.

In tables 2 and 3, the symbol "1" and the symbol "2" denote the content (added) per 100 parts by mass of the entire polymer, and the symbol "3" denotes the amount (mass) of the solvent per 100 parts by mass of the liquid crystal aligning agent.

[ Table 2]

[ Table 3]

< manufacture of liquid crystal display element by Brush-grinding method >

An electrode-carrying substrate having a length of 30mm × a width of 35mm and a thickness of 0.7mm was prepared. An IZO electrode having a solid pattern for constituting a counter electrode is formed as a1 st layer on a substrate. On the counter electrode of the 1 st layer, a SiN (silicon nitride) film formed by a CVD method was formed as the 2 nd layer. The SiN film of the 2 nd layer has a film thickness of 500nm and functions as an interlayer insulating film. On the SiN film of the 2 nd layer, a comb-shaped pixel electrode formed by patterning an IZO film is disposed as a 3 rd layer, thereby forming two pixels, i.e., a1 st pixel and a2 nd pixel. 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-like shape in which a plurality of electrode elements each having a shape like a letter "く with a bent central portion are arranged (see fig. 3 of japanese patent application laid-open No. 2014-77845). 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 each having a bent central portion, each pixel has a shape similar to a bold "く" in which the central portion is bent in the same manner as the electrode elements, instead of a rectangular shape. Each pixel is divided vertically with a curved portion at the center as a boundary, and has a1 st region on the upper side and a2 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 such 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 such that the electrode element of the pixel electrode is at an angle of-10 ° (counterclockwise). 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.

Then, the obtained liquid crystal aligning agent was filtered through a filter having a pore diameter of 1.0 μm, and then spin-coated on the substrate with electrodes and a glass substrate having an ITO film formed on the back surface thereof as a counter substrate and having a columnar spacer having a height of 4 μm, respectively. Then, the film was dried on a hot plate at 80 ℃ for 5 minutes and then fired at 230 ℃ for 20 minutes to obtain a polyimide film having a film thickness of 60nm on each substrate. The polyimide film was brushed with a rayon cloth under conditions of a roll diameter of 120mm, a roll rotation speed of 500rpm, a table movement speed of 30 mm/sec and a brush cloth pressing pressure of 0.3mm, then subjected to ultrasonic irradiation in pure water for 1 minute, and dried at 80 ℃ for 10 minutes.

The 2 kinds of substrates with the liquid crystal alignment films were combined so that the brushing directions thereof were antiparallel to each other, and the periphery thereof was sealed with an injection port for liquid crystal left, thereby producing empty cells having a cell gap of 3.8 μm. After vacuum-injecting a liquid crystal (MLC-3019, manufactured by Merck) into the empty cell at room temperature, the injection port was sealed to form an antiparallel aligned liquid crystal cell. The resulting liquid crystal cell constitutes an FFS mode liquid crystal display element. After that, the liquid crystal cell was heated at 120 ℃ for 1 hour, and placed late for evaluation.

< evaluation of afterimage elimination time >

The manufactured liquid crystal cell was placed between 2 polarizing plates arranged so that the polarization axes were orthogonal to each other, and the LED 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 minimized. Then, while an ac voltage having a frequency of 30Hz was applied to the liquid crystal cell, a V-T curve (voltage-transmittance curve) was measured, and an ac voltage having a relative transmittance of 23% was calculated as a driving voltage.

In the image sticking evaluation, the liquid crystal cell was driven by applying an alternating voltage having a frequency of 30Hz and a relative transmittance of 23%, and a direct voltage of 1V was simultaneously applied for 30 minutes. Thereafter, the dc voltage application was set to 0V, and the dc voltage application was stopped only, and the operation was further continued for 15 minutes.

In the afterimage evaluation, the time until 30 minutes elapsed from the start of application of the dc voltage was counted as the time when the relative transmittance decreased to 30% or less. The relative transmittance was reduced to 30% or less within 5 minutes and evaluated as "good" and "Δ" within 6 to 30 minutes. When 30 minutes or more was required until the relative transmittance decreased to 30% or less, the residual image was regarded as "x". The evaluation of the residual image according to the above method was performed under a temperature condition in which the temperature of the liquid crystal cell was 23 ℃.

< evaluation of flicker Change occurring immediately after the start of Driving >

The manufactured liquid crystal cell was placed between 2 polarizing plates arranged so that the polarization axes were orthogonal to each other, and the LED 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 minimized. Then, while an ac voltage having a frequency of 30Hz was applied to the liquid crystal cell, a V-T curve (voltage-transmittance curve) was measured, and an ac voltage having a relative transmittance of 23% was calculated as a driving voltage.

In the measurement of the flicker level, the lit LED backlight was temporarily turned off, left without light for 72 hours, and then the LED backlight was turned on again, and the liquid crystal cell was driven for 60 minutes by applying an ac voltage having a frequency of 30Hz and a relative transmittance of 23% while starting to light the backlight, thereby tracking the flicker amplitude. The flicker amplitude was 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 an LED backlight through 2 polarizers and a 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 level, a case where the flicker level was maintained at less than 3% from the time when the LED backlight was turned on and the ac voltage was applied until 60 minutes elapsed was defined and evaluated as "o". The case where the flicker level reached 3% or more in 60 minutes was defined and evaluated as "x".

The evaluation of the flicker level according to the above method was performed under the temperature condition that the temperature of the liquid crystal cell was 23 ℃.

< evaluation result >

The evaluation results of the sticking erasing time and the flicker change occurring immediately after the start of driving, which were carried out in the above-described examples 1,2, 4 and 5 and comparative examples 1 to 4, 6 and 7, for the liquid crystal display elements using the liquid crystal aligning agents, respectively, are shown in tables 4 to 6.

In tables 4 to 6, the symbol "1" indicates the content (mass part) of each polymer with respect to 100 mass parts of the total polymer.

[ Table 4]

[ Table 5]

[ Table 6]

As is clear from tables 4 to 6, the liquid crystal display elements using the liquid crystal aligning agents of examples 1,2, 4 and 5 have a rapid relaxation of accumulated charges and are less likely to cause a flicker change immediately after the start of driving.

< production of liquid Crystal display element by photo-alignment method >

After filtering the liquid crystal aligning agent with a filter having a pore size of 1.0 μm,the prepared substrate with electrodes and a glass substrate having an ITO film formed on the back surface thereof as a counter substrate and a columnar spacer having a height of 4 μm were spin-coated, respectively. Subsequently, the film was dried on a hot plate at 80 ℃ for 5 minutes, and then baked at 230 ℃ for 30 minutes to form a coating film having a thickness of 100nm, thereby obtaining a polyimide film on each substrate. The coated surface was irradiated with a polarizing plate to obtain a film having an extinction ratio of 26: 1 linearly polarized ultraviolet ray of 254nm wavelength of 250mJ/cm²。

The substrate was immersed in an EL (ethyl lactate) solution at 25 ℃ for 5 minutes, then immersed in pure water at 25 ℃ for 1 minute, and then heated on a hot plate at 230 ℃ for 30 minutes to obtain a substrate with a liquid crystal alignment film. The 2 substrates were used as a set, a sealant was printed on the substrates, and another 1 substrate was bonded so that the liquid crystal alignment films face each other and the alignment direction was 0 °, and then the sealant was cured to prepare an empty cell. MLC-7026-100 (manufactured by Merck corporation) in which a negative type liquid crystal was injected into the empty cell by a reduced pressure injection method, the injection port was sealed to obtain an FFS-driven liquid crystal cell. After that, the resulting liquid crystal cell was heated at 110 ℃ for 1 hour, and placed late for each evaluation.

< evaluation of afterimage elimination time >

The optical system of the liquid crystal display element by the photo-alignment method prepared in the above was used to evaluate the image sticking, as in the case of the liquid crystal display element by the rubbing method.

< evaluation of flicker level immediately after Driving >

Similarly to the case of the liquid crystal display element by the rubbing method, the optical system of the liquid crystal display element by the photo-alignment method prepared above was used to evaluate the image sticking.

< evaluation result >

The results of evaluation of the afterimage erasing time and the flicker level immediately after driving performed on the liquid crystal display element using the liquid crystal aligning agent obtained in example 12 and comparative example 7 are shown in table 7. In table 7, the color "1" indicates the content (mass part) of each polymer with respect to 100 mass parts of the total polymer.

[ Table 7]

As is clear from table 7, the liquid crystal display element using the liquid crystal aligning agent of example 12 exhibited a rapid relaxation of the accumulated charge and hardly exhibited a flicker change immediately after the start of driving.

Industrial applicability

The liquid crystal aligning agent using the novel polymer of the present invention is widely used in liquid crystal display devices of a vertical electric field system such as a TN system and a VA system, and particularly a horizontal electric field system such as an IPS system and an FFS system.

The entire contents of the specification, claims and abstract of japanese patent application 2016-191765 filed 2016, 9, 29, 2016 are hereby incorporated as the disclosure of the present invention.

Claims (15)

1. A liquid crystal aligning agent characterized by containing a polymer obtained from a diamine having a structure represented by the following formula (1) and an organic solvent,

in the formula (1), R¹、R²Is a hydrogen atom or a 1-valent organic group, any hydrogen atom of the phenyl ring being optionally substituted by a 1-valent organic group, representing the bonding site.

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

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine is represented by the following formula (2),

in the formula (2), R¹And R²Is as defined for said formula (1), R³Each independently represents a single bond or a structure of the following formula (3), n represents an integer of 1 to 3, any hydrogen atom of the benzene ring is optionally substituted by a 1-valent organic group,

in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-and-NHCO-, wherein l and m represent integers of 1-5₁Represents a site bonded to the benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2).

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

in the formula (4), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic group derived from a diamine represented by the formula (1), R₅Is 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 (4), X₁Is at least 1 selected from the group consisting of the following structures (A-1) to (A-21),

6. the liquid crystal aligning agent according to claim 4 or 5, wherein the polymer having the structural unit represented by the formula (4) 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 1 or 2, wherein the organic solvent contains at least 1 selected from the group consisting of 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether.

8. A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of claims 1 to 7.

9. A liquid crystal display element comprising the liquid crystal alignment film according to claim 8.

10. The liquid crystal display element according to claim 9, wherein the liquid crystal display element is of a lateral electric field driving type.

11. A polymer which is at least 1 selected from the group consisting of polyimide precursors and imide compounds thereof, namely, polyimide, wherein the polyimide precursors are polycondensates of diamines and tetracarboxylic dianhydrides having a structure represented by the following formula (1),

in the formula (1), R¹、R²Is a hydrogen atom or a 1-valent organic group, any hydrogen atom of the phenyl ring being optionally substituted by a 1-valent organic group, representing the bonding site.

12. The polymer according to claim 11, wherein the diamine is represented by the following formula (2),

in the formula (2), R¹And R²Is as defined for said formula (1), R³Each independently represents a single bond or a structure represented by the following formula (3), n represents an integer of 1 to 3, any hydrogen atom of the benzene ring is optionally substituted by a 1-valent organic group,

in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-and-NHCO-, wherein l and m represent integers of 1-5₁Represents a site bonded to a benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2).

13. The polymer according to claim 11 or 12, wherein the polyimide precursor is represented by the following formula (4),

in the formula (4), X₁Is a 4-valent organic radical derived from a tetracarboxylic acid derivative, Y₁Is a 2-valent organic group derived from a diamine represented by the formula (1), R₅Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

14. The polymer according to claim 13, wherein in the formula (4), X₁Is at least 1 selected from the group consisting of the following structures (A-1) to (A-21),

15. a diamine represented by the following formula (2),

in the formula (2), R¹、R²Is a hydrogen atom or a 1-valent organic radical, R³Each independently represents a single bond or a structure represented by the following formula (3), n represents an integer of 1 to 3, any hydrogen atom of the benzene ring is optionally substituted by a 1-valent organic group,

in the formula (3), R⁴Represents a single bond selected from-O-, -COO-, -OCO-, - (CH)₂)_l-、-O(CH₂)_m2-valent organic groups of O-, -CONH-and-NHCO-, wherein l and m represent integers of 1-5₁Represents a site bonded to the benzene ring in the formula (2)₂Represents a site bonded to an amino group in the formula (2).