WO2018066607A1 - Diamine, polymer, liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

A diamine having a structure represented by formula [1]. (In formula [1], Y¹ and Y² independently represent a single bond, -O-, -S-, -COO- or -OCO-; R¹ and R² independently represent -H, -OH, =O or a monovalent organic group; and R³ and R⁴ independently represent an alkylene group having 1 to 3 carbon atoms; wherein an arbitrary hydrogen atom on the benzene ring may be substituted by a monovalent organic group.)

Description

Diamine, polymer, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

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

Currently, liquid crystal display elements are widely used as display units for personal computers, mobile phones, television receivers, and the like. The liquid crystal display element includes, for example, a liquid crystal layer sandwiched 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, a liquid crystal alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, A thin film transistor (TFT) for switching an electric signal supplied to the pixel electrode is provided. Among these, the liquid crystal alignment film is formed by applying a polyimide-based liquid crystal alignment agent composed of a polyamic acid (also referred to as “polyamic acid”) that is a polyimide precursor or a polyimide solution that is an imidized product to a substrate. It is made by filming.

In recent years, liquid crystal display elements have been improved in performance, increased in area, and reduced in power consumption of display devices. In addition, they have been used in various environments, and the characteristics required for liquid crystal alignment films are severe. It has become. Therefore, various methods such as changing the structure of polyamic acid and polyimide, adding blends and additives of polyamic acid and polyimide with different characteristics, etc. can improve liquid crystal orientation and electrical characteristics, etc., and control pretilt angle etc. Has been done.

As an example of a technique for improving the characteristics of a liquid crystal alignment film, application of a diamine having a novel structure, which is a raw material for polyamic acid, has been proposed. For example, Patent Document 1 discloses a liquid crystal aligning agent containing a diamine having a novel structure and an aliphatic tetracarboxylic acid derivative. By using this liquid crystal aligning agent, the voltage holding ratio is excellent, and the charge is A liquid crystal display element capable of reducing accumulation can be provided.

However, as the performance of liquid crystal display elements increases, the characteristics required for the liquid crystal alignment film are becoming stricter, and it is difficult to satisfy all the required characteristics only with the conventional technology.

International Publication No. 2010/053128

In view of such circumstances, the present invention provides a novel diamine for improving the characteristics of a liquid crystal display element, a polymer used for the liquid crystal display element, a liquid crystal alignment agent and a liquid crystal alignment film, and a liquid crystal display element. With the goal.

As a result of intensive studies, the present inventors have found that, when a polymer obtained by using a specific diamine is applied to a liquid crystal display element, it is extremely effective for reducing flicker (flicker) at the initial stage of driving. As a result, the present invention has been completed. In addition, the diamine of the present invention described later is a novel compound not described in any literature.

The diamine of the present invention that achieves the above object is represented by the following formula [1].

(In Formula [1], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, and R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and any hydrogen atom of the benzene ring is And may be substituted with a monovalent organic group.)

The polymer of the present invention that achieves the above object is obtained from a diamine component containing a diamine having a structure represented by the following formula [2].

(In Formula [2], Y ¹ is a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, O or a monovalent organic group, R ³ is an alkylene group having 1 to 3 carbon atoms, * represents a site bonded to another group, and any hydrogen atom of the benzene ring is (It may be substituted with a monovalent organic group.)

The polymer is preferably obtained from a diamine component containing a diamine having a structure represented by the following formula [3].

(In Formula [3], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and * is a site bonded to another group In addition, any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)

Further, the polymer is preferably at least one selected from a polyimide precursor containing a structural unit represented by the following formula [4] and a polyimide which is an imide compound thereof.

(In Formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent derived from a diamine having a structure represented by Formula [2] or Formula [3]. R ⁵ and R ^{6 each} represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and A ¹ and A ² each independently represent a hydrogen atom or a carbon atom having 1 to 5 carbon atoms. Represents an alkyl group, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.)

The liquid crystal aligning agent of the present invention that achieves the above object is characterized by containing a polymer and an organic solvent.

The liquid crystal alignment film of the present invention that achieves the above object is obtained from the above liquid crystal aligning agent.

The liquid crystal display element of the present invention that achieves the above object is characterized by comprising the above liquid crystal alignment film.

According to the present invention, a novel diamine for improving the characteristics of a liquid crystal display element, a polymer used for the liquid crystal display element, a liquid crystal aligning agent and a liquid crystal alignment film, and a liquid crystal display element can be provided.

Hereinafter, the present invention will be described in more detail.
<Diamine>
The diamine of the present invention is represented by the following formula [1].

(In Formula [1], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, and R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and any hydrogen atom of the benzene ring is And may be substituted with a monovalent organic group.)

In the formula [1], the monovalent organic group includes a hydrocarbon group; a hydrocarbon group containing a hydroxyl group, a carboxyl group, a hydroxyl group, a thiol group, or a carboxyl group; a bonding group such as an ether bond, an ester bond, or an amide bond. A hydrocarbon group linked by: a hydrocarbon group containing a silicon atom; a halogenated hydrocarbon group; an amino group; an inert group in which the amino group is protected by a carbamate-based protecting group such as a t-butoxycarbonyl group, etc. Can be mentioned. The hydrocarbon group may be a straight chain, branched chain or cyclic chain, and may be a saturated hydrocarbon or an unsaturated hydrocarbon. In addition, some of the hydrogen atoms of the hydrocarbon group may be replaced by carboxyl groups, hydroxyl groups, thiol groups, silicon atoms, halogen atoms, etc., and are linked by a linking group such as an ether bond, an ester bond, or an amide bond. It may be.

In addition, the alkylene group having 1 to 3 carbon atoms may be a straight chain, a branched chain or a cyclic chain. Specifically, methylene group, ethylene group, n-propylene group, isopropylene group, cyclopropylene group, 1-methyl-cyclopropylene group, 2-methyl-cyclopropylene group, 1,1-dimethyl-n-propylene group 1,2-dimethyl-n-propylene group, 2,2-dimethyl-n-propylene group, 1-ethyl-n-propylene group, 1,2-dimethyl-cyclopropylene group, 2,3-dimethyl-cyclopropylene 1-ethyl-cyclopropylene group, 2-ethyl-cyclopropylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2-trimethyl-n-propylene group, 1-ethyl-1- Methyl-n-propylene group, 1-ethyl-2-methyl-n-propylene group, 2-n-propyl-cyclopropylene group, 1-isopropyl-cyclopropyl group Pyrene group, 2-isopropyl-cyclopropylene group, 1,2,2-trimethyl-cyclopropylene group, 1,2,3-trimethyl-cyclopropylene group, 2,2,3-trimethyl-cyclopropylene group, 1-ethyl Examples include -2-methyl-cyclopropylene group, 2-ethyl-1-methyl-cyclopropylene group, 2-ethyl-2-methyl-cyclopropylene group and 2-ethyl-3-methyl-cyclopropylene group.

In addition, a monovalent organic group or an alkylene group having 1 to 3 carbon atoms can be variously selected depending on applications.

Specific examples of the diamine represented by the formula [1] include, but are not limited to, diamines represented by the following formulas [5-1] to [5-13].

In the formula [5-3], Boc represents a group represented by the following (tert-butoxycarbonyl group).

<Synthesis method of diamine>
Next, main methods for synthesizing the diamine of the present invention will be described. Note that the method described below is a synthesis example and is not limited thereto.

The diamine of the present invention can be obtained by reducing a dinitro compound and converting a nitro group to an amino group as shown in the following reaction formula. In the following reaction formula, a diamine in which the hydrogen atom of the benzene ring and the saturated hydrocarbon portion is not substituted with a halogen atom such as a fluorine atom or a monovalent organic group other than an amino group is described as an example.

(In the above reaction formula, Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently — H, —OH, ═O or a monovalent organic group, and R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and any hydrogen atom of the benzene ring is (It may be substituted with a monovalent organic group.)

The method for reducing the dinitro compound is not particularly limited, and palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, platinum sulfide carbon, etc. are used as a catalyst, such as ethyl acetate, toluene, tetrahydrofuran, dioxane, alcohols, etc. Examples of the method include reduction with hydrogen gas, hydrazine, hydrogen chloride or the like in a solvent. You may carry out under pressure using an autoclave etc. as needed. On the other hand, when an unsaturated bond site is included in the structure of a substituent that replaces the hydrogen atom of the benzene ring or the saturated hydrocarbon portion, use of palladium carbon, platinum carbon, or the like reduces the unsaturated bond site and causes saturation. Since there exists a possibility that it may become a coupling | bonding, the reduction conditions using transition metals, such as reduced iron, tin, and tin chloride, as a catalyst are preferable.

The above reaction can be performed in the presence of a base. The base to be used is not particularly limited as long as it can be synthesized, but inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, sodium hydride, pyridine, dimethyl And organic bases such as aminopyridine, trimethylamine, triethylamine, and tributylamine. In some cases, when a palladium catalyst such as dibenzylideneacetone palladium or diphenylphosphinoferrocene palladium, a copper catalyst, or the like is used in combination, the yield can be improved.

The diamine of the present invention thus obtained can be used as a raw material for polyimide precursors such as polyamic acid and polyamic acid ester, polyimide, polyurea, polyamide and the like (collectively referred to as “polymer”). This polymer can be used, for example, as a liquid crystal aligning agent by being dissolved in a predetermined organic solvent, but is not limited to its use. Hereinafter, the polymer containing the diamine represented by the formula [1] in the structure will be described.

<Polymer>
The polymer of the present invention is obtained using the above-described diamine of the present invention or a derivative thereof (described later), and has a structure represented by the following formula [2] derived from the diamine component.

(In Formula [2], Y ¹ is a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, O or a monovalent organic group, R ³ is an alkylene group having 1 to 3 carbon atoms, * represents a site bonded to another group, and any hydrogen atom of the benzene ring is (It may be substituted with a monovalent organic group.)

As the structure represented by the formula [2] derived from the diamine component of such a polymer, those having a structure represented by the following formula [3] are preferable.

(In Formula [3], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and * is a site bonded to another group In addition, any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)

Here, examples of the derivative of the diamine of the present invention include a diamine having a structure in which two or more of the diamines are connected or a structure in which the diamine is connected through the Y ¹ or Y ² . Further, the structure derived from the diamine component may include a structure derived from other diamine (described later) in addition to the structure of the formula [2].

In addition, examples of the monovalent organic group and the alkylene group having 1 to 3 carbon atoms in the formula [2] and the formula [3] include those similar to the formula [1].

The polymer of the present invention is at least one selected from a polyimide precursor containing a structural unit represented by the following formula [4] and a polyimide that is an imide compound thereof, from the viewpoint of use as a liquid crystal aligning agent. It is preferable.

(In Formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent derived from a diamine having a structure represented by Formula [2] or Formula [3]. R ⁵ and R ^{6 each} represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and A ¹ and A ² each independently represent a hydrogen atom or a carbon atom having 1 to 5 carbon atoms. Represents an alkyl group, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.)

In the formula [4], examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and an n-pentyl group. Group, isopentyl group, s-pentyl group, t-pentyl group and the like. Examples of the alkenyl group having 2 to 5 carbon atoms include vinyl group, allyl group, 1-propenyl group, 1-butenyl group, 2 -Butenyl group, 3-butenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group and the like. Examples of the alkynyl group having 2 to 5 carbon atoms include ethynyl group, Examples include 1-propynyl group, 2-propynyl (propargyl) group, 3-butynyl group, pentynyl group and the like. Among these, R ⁵ and R ⁶ are preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group, from the viewpoint of easy progress of the imidization reaction during heating, and liquid crystal alignment properties. In view of the above, A ¹ and A ² are preferably a hydrogen atom or a methyl group.

The structure of X ¹ is not particularly limited as long as it is a tetravalent organic group derived from a tetracarboxylic acid derivative. Moreover, X ¹ is coatability solubility and liquid crystal alignment agent in the solvent of the polymer liquid crystal orientation in the case where the liquid crystal alignment film, the voltage holding ratio, such stored charge, the degree of properties required Depending on the selection, one type may be used in the same polymer, or two or more types may be mixed.

X ¹ is not only a tetracarboxylic dianhydride but also a tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester compound or tetracarboxylic acid dialkyl ester dihalide compound which is a tetracarboxylic acid derivative thereof. it can. As the tetracarboxylic dianhydride or a derivative thereof, it is more preferable to use at least one selected from the tetracarboxylic dianhydrides represented by the following formula [6] or a derivative thereof.

In the formula [6], V ¹ is a tetravalent organic group having an alicyclic structure, and the structure is not particularly limited. Specific examples include the following formula [V ¹ -1] to formula [V ¹ -44].

In the formulas [V ¹ -1] to [V ¹ -4], R ⁷ to R ²⁷ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or 2 to 2 carbon atoms. A alkenyl group having 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, which may be the same or different. From the viewpoint of liquid crystal orientation, R ⁷ to R ²⁷ are preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom or a methyl group.

Specific structures of the formula [V ¹ -1] include structures represented by the following formulas [V ¹ -1-1] to [V ¹ -1-6]. A structure represented by the following formula [V ¹ -1-1] is particularly preferable from the viewpoint of liquid crystal alignment and photoreaction sensitivity.

In Formula [4], W ¹ is not particularly limited as long as W ¹ is a divalent organic group derived from a diamine having a structure represented by Formula [2] or Formula [3]. More than one type may be mixed. W ¹ corresponds to the structure of the diamine component used in the present invention and has a specific diamine having a structure represented by the formula [1] (for example, the following formula [W ¹ -1] to formula [W ¹ -13] at least one diamine selected from the group consisting of compounds represented by

In the formula [W ¹ -3], Boc represents a group represented by the following (tert-butoxycarbonyl group).

However, it is not always necessary that all of W ¹ have a structure corresponding to the diamine. A part of W ¹ may contain a structure corresponding to a diamine other than the diamine (other diamine). The structure corresponding to the other diamine (hereinafter referred to as “structure W ² ”) can be generalized as represented by the following formula [7]. As the ^{A 1} and ^{A 2} in the formula [7] are the same as those for the formula [4].

Further, the structure W ² represented by the formula [7] is exemplified by the following formula [W ² -1] to the formula [W ² -173].

Note that the Boc group in the formula [W ² -168], the formula [W ² -169], the formula [W ² -172] and the formula [W ² -173] is a tert-butoxycarbonyl group shown below. Represents.

When the polyimide precursor containing the structural unit represented by the formula [4] includes the structural unit represented by the formula [7] at the same time, the structural unit represented by the formula [4] is represented by the formula [4] and the formula It is preferable that it is 10 mol% or more with respect to the sum total of [7], More preferably, it is 20 mol% or more, Most preferably, it is 30 mol% or more.

The molecular weight of the polyimide precursor or polyimide, which is the polymer of the present invention, is determined when the liquid crystal alignment film is obtained from a liquid crystal aligning agent containing the polymer, the strength of the coating film (liquid crystal alignment film), and the coating film formation. The weight average molecular weight measured by GPC (Gel Permeation Chromatography) method is preferably 2,000 to 500,000, considering the workability at the time and the uniformity of the coating film, preferably 5,000 to 300,000 More preferably, it is 10,000 to 100,000.

<Method for producing polymer>
Next, the main manufacturing method of the polymer of this invention is demonstrated. In addition, the method demonstrated below is a manufacture example and is not limited to this.

For example, when the polymer containing the structural unit represented by the formula [4] is a polyamic acid that is a polyimide precursor, the polymer includes a tetracarboxylic dianhydride that is a tetracarboxylic acid derivative and a diamine component. Is obtained by reaction with In obtaining the polyamic acid by this reaction, a known synthesis method can be used. The synthesis method is a method in which a tetracarboxylic dianhydride and a diamine component are reacted in an organic solvent. Such a method is advantageous in that it proceeds relatively easily in an organic solvent and no by-products are generated.

The organic solvent used in the above reaction is not particularly limited as long as the produced polyamic acid (polymer) can be dissolved. For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2 -Pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, Methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl Thor, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol Monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether Dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl buty Rate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, acetic acid Methyl, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 3-methoxy Methyl propionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy Examples include -4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like. These may be used alone or in combination. Moreover, even if it is a solvent which does not dissolve a polyamic acid (polymer), you may mix and use the said organic solvent in the range which the produced | generated polyamic acid does not precipitate. In particular, water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyamic acid. Therefore, it is preferable to use a dehydrated and dried organic solvent as much as possible.

When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, the solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic dianhydride is used as it is or in an organic solvent. A method of adding by dispersing or dissolving, a method of adding a diamine component to a solution in which tetracarboxylic dianhydride is dispersed or dissolved in an organic solvent, a method of adding tetracarboxylic dianhydride and diamine component alternately, etc. Any of these methods may be used. Further, when the tetracarboxylic dianhydride or diamine component is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be individually reacted sequentially, or may be further reacted individually. May be mixed to form a high molecular weight product.

In this case, the polycondensation temperature can be selected from -20 ° C to 150 ° C, but it is preferably in the range of -5 ° C to 100 ° C. The polycondensation reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution will become too high and uniform stirring will occur. Therefore, the total concentration of the tetracarboxylic dianhydride and the diamine component in the reaction solution is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass. The initial stage of the reaction may be performed at a high concentration, and then an organic solvent may be added.

In the polymerization reaction of polyamic acid, the ratio of the total number of moles of tetracarboxylic dianhydride and the total number of moles of diamine component (total number of moles of tetracarboxylic dianhydride / total number of moles of diamine component) is 0. It is preferably 8 to 1.2. Similar to the normal polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the polyamic acid produced.

When the polymer containing the structural unit represented by the formula [4] is a polyamic acid ester, a reaction between tetracarboxylic acid diester dichloride and a diamine component, or a suitable condensing agent for converting the tetracarboxylic acid diester and diamine component. It can obtain by making it react in presence of a base. Alternatively, it can also be obtained by previously synthesizing a polyamic acid by the above method and esterifying the carboxylic acid in the amic acid using a polymer reaction.

Specifically, for example, tetracarboxylic acid diester dichloride and diamine are -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C in the presence of a base and an organic solvent, for 30 minutes to 24 hours, preferably 1 By reacting for 4 to 4 hours, a polyamic acid ester can be synthesized.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times mol of tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

Further, when polycondensation of tetracarboxylic acid diester and diamine component in the presence of a condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium Tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxa Zolyl) phosphonic acid diphenyl, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl It can be used 4-methoxy mol ho potassium chloride n- hydrate.

In the method using the condensing agent, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The amount of Lewis acid added is preferably 0.1 to 1.0 times the molar amount of the diamine or tetracarboxylic acid diester to be reacted.

The solvent used in the above reaction can be the same solvent as that used in the synthesis of the polyamic acid shown above, but N-methyl-2-pyrrolidone, γ -Butyrolactone is preferred, and these may be used alone or in combination of two or more. The concentration at the time of synthesis is such that in the reaction solution of a tetracarboxylic acid derivative such as tetracarboxylic acid diester dichloride or tetracarboxylic acid diester and a diamine component, from the viewpoint that polymer precipitation is difficult to occur and a high molecular weight product is easily obtained. The total concentration is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass. Moreover, in order to prevent hydrolysis of tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

In the case where the polymer containing the structural unit represented by the formula [4] is a polyimide, it has a divalent group represented by the formula [2] or the formula [3] in the main chain, and It can be obtained by dehydrating and ring-closing polyamic acid. In this polyimide, the dehydration cyclization rate (imidization rate) of the amic acid group is not necessarily 100%, and can be arbitrarily adjusted according to the application and purpose.

Examples of the method for imidizing polyamic acid include thermal imidization in which a polyamic acid solution is heated as it is, and catalytic imidization in which a catalyst is added to a polyamic acid solution.

The temperature at which the polyamic acid is thermally imidized in the solution is 100 ° C. to 400 ° C., preferably 120 ° C. to 250 ° C., and is preferably carried out while removing water generated by the imidization reaction from the outside of the system.

The catalytic imidation of polyamic acid can be carried out by adding a basic catalyst and an acid anhydride to a polyamic acid solution and stirring at -20 ° C to 250 ° C, preferably 0 ° C to 180 ° C. The amount of the basic catalyst is 0.5 mol times to 30 mol times, preferably 2 mol times to 20 mol times of the amic acid groups, and the amount of the acid anhydride is 1 mol times to 50 mol times of the amic acid groups, The amount is preferably 3 mole times to 30 mole times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

As described above, polyimide can also be obtained by heating a polyamic acid ester at a high temperature to promote dealcoholization and ring closure.

In addition, when recovering the generated polyamic acid, polyamic acid ester, and polyimide from a polyimide precursor such as polyamic acid or polyamic acid ester, or a reaction solution of polyimide, the reaction solution is poured into a poor solvent and precipitated. That's fine. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. After the polyimide precursor and polyimide which have been put into a poor solvent and precipitated are collected by filtration, they can be dried at normal temperature or under reduced pressure at room temperature or by heating. In addition, the impurities in the polymer can be reduced by repeating the steps of re-dissolving the precipitated and recovered polyimide precursor and polyimide in an organic solvent and repeating the reprecipitation and recovery 2 to 10 times. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more kinds of poor solvents selected from these because purification efficiency is further improved.

The polymer of the present invention thus obtained can be dissolved in a predetermined organic solvent and used as a liquid crystal aligning agent. This liquid crystal aligning agent is used for the liquid crystal aligning film which controls the orientation of the liquid crystal molecule of a liquid crystal layer in a liquid crystal display element. Hereinafter, the liquid crystal aligning agent containing the polymer of this invention is demonstrated.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention contains the polymer obtained from the diamine component containing the diamine which has a structure represented by Formula [2] derived from the said diamine component. Moreover, it is preferable that this liquid crystal aligning agent contains the polymer which has a structure represented by Formula [3] derived from the said diamine component. Moreover, it is preferable that this polymer is at least 1 type selected from the polyimide precursor containing the structural unit represented by Formula [4], and the polyimide which is the imide compound.

However, the polymers contained in the liquid crystal aligning agent of the present invention may all be the polymers of the present invention, and are different from the polymers of the present invention as long as the effects described in the present invention are exhibited. You may contain 2 or more types of structures. Or in addition to the polymer of this invention, you may contain the other polymer, ie, the polymer which does not have a bivalent group represented by Formula [2] or Formula [3]. Other polymer types include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or derivatives thereof, poly (styrene-phenylmaleimide) derivative, poly (meta ) Acrylate and the like.

When the liquid crystal aligning agent of the present invention contains other polymers, the ratio of the polymer of the present invention to the total polymer components is preferably 5% by mass or more, and an example thereof is 5% by mass to 95% by mass. Is mentioned. The ratio of the polymer of this invention can be suitably selected according to the characteristic of a liquid crystal aligning agent or a liquid crystal aligning film.

The liquid crystal aligning agent of the present invention is used for preparing a liquid crystal aligning film, and generally takes the form of a coating liquid from the viewpoint of forming a uniform thin film. Also in the liquid crystal aligning agent of this invention, it is preferable that it is a coating liquid containing an above-described polymer component and the organic solvent in which this polymer component is dissolved. At that time, the 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. From the viewpoint of forming a uniform and defect-free coating film, the content 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% by mass to 8% by mass.

The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as it is an organic solvent that dissolves the polymer. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolide. Non-methyl methyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone and the like can be mentioned. Of these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are preferably used. In addition, the organic solvent illustrated here may be used independently or may be used in mixture. Furthermore, even a solvent that does not dissolve the polymer may be used by mixing with an organic solvent as long as the produced polymer does not precipitate.

Moreover, the organic solvent contained in the liquid crystal aligning agent uses a mixed solvent that is used in combination with a solvent that improves the coating properties and the surface smoothness of the coating film when the liquid crystal aligning agent is applied in addition to the above-described solvents. Such a mixed solvent is also preferably used in the liquid crystal aligning agent of the present invention. Specific examples of the organic solvent to be used in combination are given below, but the organic solvent is not limited to these examples.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 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-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2- Ethane All, 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, 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- Ntanone, 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, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl Ether ether acetate, dipropylene glycol, 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 mono Butyl 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, triethylene glycol Ethylene 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, 3-ethoxypropion Methyl ethyl, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate And solvents such as lactic acid n-butyl ester and lactic acid isoamyl ester.

In addition to the solvents described above, for example, solvents represented by the following formulas [S-1] to [S-3] can be used.

In the formula [S-1] and [S-2], R ²⁸ and R ²⁹ represent an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. In the formula [S-3], R ³⁰ represents an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like.

Among the organic solvents used in combination, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene It is preferable to use glycol monobutyl ether or dipropylene glycol dimethyl ether. The kind and content of such a solvent are suitably selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

Further, these solvents are preferably 20% by mass to 99% by mass with respect to the whole solvent contained in the liquid crystal aligning agent. Of these, 20% by mass to 90% by mass is preferable. More preferred is 20% by mass to 70% by mass.

The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent as long as the effects of the present invention are not impaired. Examples of such additional components include an adhesion aid for increasing the adhesion between the liquid crystal alignment film and the substrate and the adhesion between the liquid crystal alignment film and the sealing material, a crosslinking agent for increasing the strength of the liquid crystal alignment film, and the liquid crystal alignment. Examples thereof include dielectrics and conductive materials for adjusting the dielectric constant and electrical resistance of the film. Specific examples of these additional components are as disclosed in various known literatures relating to liquid crystal aligning agents. However, if an example is given, paragraphs [0105] to paragraphs [0116] of WO2015 / 060357 are intended. And the like.

<Liquid crystal alignment film>
The liquid crystal aligning film of this invention is obtained from the liquid crystal aligning agent mentioned above. If an example of the method of obtaining a liquid crystal aligning film from a liquid crystal aligning agent is given, a liquid crystal aligning agent in the form of a coating solution is applied to a substrate, dried and baked on a film obtained by rubbing or photo-aligning. And a method of performing an alignment treatment.

The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with a glass substrate or a silicon nitride substrate. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed from the viewpoint of simplification of the process. In the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as it is only on one side of the substrate, and a material that reflects light such as aluminum can be used for the electrode in this case.

The application method of the liquid crystal aligning agent is not particularly limited, but industrially, screen printing, offset printing, flexographic printing, ink jet method and the like are common. As other coating methods, there are a dipping method, a roll coater method, a slit coater method, a spinner method, a spray method, and the like, and these may be used according to the purpose.

Firing after applying the liquid crystal aligning agent on the substrate is performed at 50 ° C. to 300 ° C., preferably 80 ° C. to 250 ° C. by a heating means such as a hot plate, a hot-air circulating furnace, an infrared furnace, and the solvent is evaporated, A coating film (liquid crystal alignment film) can be formed. If the thickness of the coating film formed after firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. The thickness is preferably 10 nm to 100 nm. When the liquid crystal is aligned horizontally or tilted, the fired coating film is treated by rubbing or irradiation with polarized ultraviolet rays.

After the liquid crystal aligning agent is applied on the substrate, the solvent is evaporated and baked by a heating means such as a hot plate, a thermal circulation oven, an IR (infrared) oven or the like. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent. Usually, in order to sufficiently remove the contained solvent, there is a condition of baking at 50 ° C. to 120 ° C. for 1 minute to 10 minutes and then baking at 150 ° C. to 300 ° C. for 5 minutes to 120 minutes.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a horizontal electric field type liquid crystal display element such as an IPS mode or an FFS mode, and is particularly useful as a liquid crystal alignment film for an FFS mode liquid crystal display element.

<Liquid crystal display element>
The liquid crystal display element of the present invention comprises the above-mentioned liquid crystal alignment film, and after obtaining a substrate with a liquid crystal alignment film obtained from the above-mentioned liquid crystal aligning agent, a liquid crystal cell is prepared by a known method, An element is formed using a liquid crystal cell. As an example, two substrates disposed so as to face each other, a liquid crystal layer provided between the substrates, and a liquid crystal formed between the substrate and the liquid crystal layer and formed by the liquid crystal aligning agent of the present invention. A liquid crystal display element comprising a liquid crystal cell having an alignment film.

The substrate used in the liquid crystal display element of the present invention is not particularly limited as long as it is a highly transparent substrate, but is usually a substrate on which a transparent electrode for driving liquid crystal is formed. As a specific example, the thing similar to the board | substrate described with the above-mentioned liquid crystal aligning film can be mentioned.

Further, the liquid crystal alignment film is formed by applying the liquid crystal aligning agent of the present invention on this substrate and baking it, and the details are as described above.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display element of the present invention is not particularly limited, and examples thereof include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable, and any of positive liquid crystal materials and negative liquid crystal materials can be used. It may be used. Specifically, for example, MLC-2003, MLC-6608, MLC-6609, MLC-3019, MLC-2041, MLC-7026-100 manufactured by Merck & Co., Inc. can be used.

Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be ITO electrodes, for example, and are patterned so as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a film made of SiO ₂ —TiO ₂ formed by a sol-gel method. Next, a liquid crystal alignment film is formed on each substrate under the above conditions.

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 film is formed, and liquid crystal is disposed at predetermined positions on the liquid crystal alignment film surface. After that, the other substrate is bonded and pressure-bonded so that the liquid crystal alignment film faces, and the liquid crystal is spread on the front surface of the liquid crystal alignment film, and then the entire surface of the substrate is irradiated with ultraviolet rays to cure the sealing material. Get a cell.

Alternatively, as a process after the liquid crystal alignment film is formed on the substrate, an opening that can be filled with liquid crystal from the outside is provided when a sealing material is disposed at a predetermined location on one substrate. After the substrates are bonded without being arranged, a liquid crystal material is injected into the liquid crystal cell through an opening provided in the sealing material, and then the opening 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 utilizing capillary action in the atmosphere.

In any of the above methods, in order to secure a space filled with the liquid crystal material in the liquid crystal cell, columnar protrusions are provided on one substrate, spacers are scattered on one substrate, or a sealing material It is preferable to take a means such as mixing a spacer with these or combining them.

Next, a polarizing plate is installed. Specifically, it is preferable to attach a pair of polarizing plates to the surfaces of the two 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 aligning agent of the present invention is used, and may be manufactured by other known methods. Good. Processes for obtaining a liquid crystal display element from a liquid crystal aligning agent are also disclosed in a number of documents in addition to paragraphs [0074] to [0081] of JP-A-2015-135393, for example.

As described above, the liquid crystal display device manufactured using the liquid crystal aligning agent of the present invention has excellent reliability and can be suitably used for a large-screen high-definition liquid crystal television or the like.

Hereinafter, the details of the production method of the present invention will be described with reference to an experimental method for examining the composition and blending ratio of raw materials, the results thereof, and examples that are typical production methods. It is not limited to examples.

In addition, the abbreviations of the compounds and solvents and the method of property evaluation 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 DIBK: 2,6-dimethyl-4-heptanone DIPE: Diisopropyl ether DIBC: 2,6-dimethyl-4-heptanol Pd / C: Palladium carbon DMSO: Dimethyl sulfoxide THF: Tetrahydrofuran

<Additives>
LS-4668: 3-glycidoxypropyltriethoxysilane LS-3150: 3-aminopropyltriethoxysilane

<Measurement of ¹ H-NMR>
Apparatus: Varian NMR system 400NB (400 MHz) (manufactured by Varian), and JMTC-500 / 54 / SS (500 MHz) (manufactured by JEOL)
Measuring solvent: CDCl ₃ (deuterated chloroform), DMSO-d ₆ (deuterated dimethyl sulfoxide)
Reference materials: TMS (tetramethylsilane) (δ: 0.0 ppm, ¹ H) and CDCl ₃ (δ: 77.0 ppm, ¹³ C)

<Molecular weight measurement of polyimide precursor and imidized polymer>
The measurement was performed under the following conditions using a normal temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko KK) and a column (KD-803, KD-805) (manufactured by Shodex).
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additive, lithium bromide-hydrate (LiBr · H ₂ O) 30 mmol / L (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol) / L, 10 ml / L of tetrahydrofuran (THF))
Flow rate: 1.0 ml / min Standard sample for preparing calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, and 30,000, manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: about (12,000, 4,000, and 1,000, manufactured by Polymer Laboratory)

<Viscosity measurement>
In the synthesis examples and comparative synthesis examples described later, the viscosity of the polyamic acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample amount of 1.1 mL, and cone rotor TE-1 (1 ° 34 ′ , R24).

<Synthesis of diamine compound (DA-1)>

BNPU (50 g, 140 mmol), potassium carbonate (44.4 g, 320 mmol), and NMP (1000 g) were charged into a 2 L (liter) four-necked flask, heated to 50 ° C. with wing stirring, and 40% glyoxal An aqueous solution (46.7 g, 320 mmol) was added dropwise over 10 minutes and stirred for 12 hours. Since the raw material remained by HPLC (high performance liquid chromatography), potassium carbonate (44.4 g, 320 mmol) and 40% glyoxal aqueous solution (46.7 g, 320 mmol) were further added, and the mixture was stirred for 12 hours to give compound [A]. Got. After confirming disappearance of the raw materials, the salt was filtered, sulfuric acid (15 g) was added dropwise to make the solution acidic, and the mixture was stirred at 70 ° C. for 24 hours. After confirming the completion of the reaction by HPLC, methanol (1000 g) and pure water (1000 g) were added, and the mixture was cooled to 5 ° C. and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with methanol (100 g), and then dried to obtain powder crystals (compound [B]) (yield 41.7 g, yield 76%).

¹ H-NMR (DMSO-d6): 8.18-8.10 (4H, m), 7.56-7.50 (2H, m), 7.45-7.39 (2H, m), 3 .95 (2H, s), 3.62-3.55 (4H, m), 2.97-2.91 (4H, m)

A mixture of the obtained compound [B] (35 g, 87.8 mmol), 5 mass% Pd / C (50% water-containing type), characteristic birch activated carbon (3.5 g), and dioxane (350 g) was subjected to hydrogen pressure conditions. The mixture was stirred at 60 ° C. for 8 hours. After completion of the reaction, the catalyst was filtered off, concentrated, 2-propanol (350 g) was added, and the mixture was stirred at 5 ° C. for 1 hr. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (70 g), and then dried to obtain powder crystals DA-1 (yield 27 g, yield 92%).

¹ H-NMR (DMSO-d6): 6.87-6.84 (2H, m), 6.81-6.77 (2H, m), 6.51-6.46 (4H, m), 4 .90 (4H, s), 3.79 (2H, s), 3.45-3.38 (4H, m), 2.62-2.57 (4H, m)

[Synthesis Example 1]
After adding the obtained DA-1 (3.38 g, 10.0 mmol) to a 100 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, add 28.8 g of NMP, and stir and dissolve while feeding nitrogen. I let you. While this solution was stirred, CA-1 (0.87 g, 4.0 mmol), CA-2 (1.08 g, 5.5 mmol), and 9.6 g of NMP were added, and further under 50 ° C. conditions. By stirring for 12 hours, a polyamic acid solution (PAA-A1) shown in Table 1 below was obtained.

[Synthesis Example 2 to Synthesis Example 5]
By carrying out in the same manner as in Synthesis Example 1, except that the diamine component, tetracarboxylic acid component, and NMP (N-methyl-2-pyrrolidone) shown in Table 1 below were used and the reaction temperature was set, respectively. Polyamic acid solutions (PAA-A2) and polyamic acid solutions (PAA-B1) to (PAA-B3) shown in Table 1 below were obtained.

[Examples 1 to 10 and Comparative Examples 1 and 2]
To the polyamic acid solutions obtained in Synthesis Examples 1 to 5, the solvent and additives were added while stirring so that the solvent in the obtained liquid crystal aligning agent had the composition shown in Table 2 and Table 3 below. Furthermore, the liquid crystal aligning agent was obtained by stirring at room temperature for 2 hours, respectively.

In Tables 2 and 3, * 1 to * 3 are as shown below.
* 1: Indicates the amount of each polymer introduced (parts by weight) relative to 100 parts by weight of all polymers.
* 2: Indicates the amount of each additive introduced (parts by weight) with respect to 100 parts by weight of all polymers.
* 3: The amount of solvent introduced (parts by weight) with respect to 100 parts by mass of the liquid crystal aligning agent.

<Production of liquid crystal display element by rubbing method>
A glass substrate with an electrode having a size of 30 mm × 35 mm and a thickness of 0.7 mm was prepared. On the substrate, an IZO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second SiN film, a comb-like pixel electrode formed by patterning an IZO film as the third layer is arranged to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm long and 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

The pixel electrode of the third layer is a comb tooth formed by arranging a plurality of electrode elements having a U-shape with a bent central portion as shown in FIG. 3 (Japanese Patent Laid-Open No. 2014-77845). It has a shape. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is formed by arranging a plurality of bent-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that bends and resembles a bold-faced koji. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode elements of the electrode are formed so as to form an angle of −10 ° (clockwise). Further, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode in the substrate surface are mutually It is comprised so that it may become a reverse direction.

Next, after the liquid crystal aligning agent is filtered through a 1.0 μm filter, each of the glass substrates having a columnar spacer having a height of 4 μm and an ITO film formed on the back surface as the above-mentioned substrate with electrodes and a counter substrate. Spin coated. Subsequently, after drying for 5 minutes on an 80 degreeC hotplate, it baked for 20 minutes at 230 degreeC, and obtained the 60-nm-thick polyimide film on each board | substrate. The polyimide film surface is rubbed with a rayon cloth under the conditions of a roll diameter of 120 mm, a roller rotation speed of 500 rpm, a stage moving speed of 30 mm / sec, and a rubbing cloth indentation pressure of 0.3 mm, and then in pure water for 1 minute. Ultrasonic irradiation was performed, and drying was performed at 80 ° C. for 10 minutes.

Using the two types of substrates with the above-mentioned liquid crystal alignment film, the rubbing directions were combined to be antiparallel, the periphery was sealed leaving the liquid crystal injection port, and an empty cell with a cell gap of 3.8 μm was produced. . Liquid crystals (MLC-3019, manufactured by Merck & Co., Inc.) were vacuum-injected into this empty cell at room temperature, and the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Thereafter, the liquid crystal cell was heated at 120 ° C. for 1 hour and allowed to stand overnight before being used for evaluation.

<Evaluation of flicker level immediately after driving>
The prepared liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on with no voltage applied, so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Next, a VT curve (voltage-transmittance curve) was measured while applying an AC voltage with a frequency of 30 Hz to the liquid crystal cell, and an AC voltage with a relative transmittance of 23% was calculated as a drive voltage.

In the measurement of the flicker level, the LED backlight that was turned on is temporarily turned off and left to block light for 72 hours, and then the LED backlight is turned on again. The frequency at which the relative transmittance becomes 23% at the same time when the backlight turns on is 30 Hz. The AC voltage was applied and the liquid crystal cell was driven for 60 minutes to track the flicker amplitude. The flicker amplitude is a data collection / data logger switch unit 34970A (Agilent technologies) connected through a photodiode and an IV conversion amplifier to the transmitted light of the LED backlight that has passed through two polarizing plates and a liquid crystal cell therebetween. ). The flicker level was calculated by the following formula [8].
Flicker level (%) = {flicker amplitude / (2 × z)} × 100 (8)

In the equation [8], z is a value obtained by reading the luminance when driven by an AC voltage with a frequency of 30 Hz with a relative transmittance of 23% by the data collection / data logger switch unit 34970A.

The flicker level is evaluated as “◯” (flicker immediately after the start of driving) when the flicker level is kept below 3% by the time 60 minutes have elapsed since the start of lighting of the LED backlight and application of the AC voltage. The evaluation was performed with the definition that the shift is unlikely to occur. When the flicker level reached 3% or more in 60 minutes, the evaluation was defined as “x” (flicker shift is likely to occur immediately after the start of driving).

And the evaluation of the flicker level according to the method described above was performed under the temperature condition where the temperature of the liquid crystal cell was 23 ° C.

<Evaluation results>
Regarding the liquid crystal display elements using the liquid crystal aligning agents of Examples 1 and 2 and Comparative Examples 1 and 2, the results of evaluation of afterimage erasing time and flicker level immediately after driving are shown in Table 4 below. Shown in

As seen in Table 4, it can be seen that the liquid crystal display elements using the liquid crystal aligning agents of Example 1 and Example 2 are unlikely to cause a flicker shift immediately after the start of driving.

The liquid crystal display element produced using the liquid crystal aligning agent obtained by the diamine of the present invention can be a liquid crystal display device with reduced flicker shift immediately after the start of driving, and is a TN (Twisted Nematic) liquid crystal display element or STN liquid crystal. It is suitably used for display elements of various systems such as display elements, TFT liquid crystal display elements, VA liquid crystal display elements, IPS liquid crystal display elements, OCB (Optically self-compensated birefringence) liquid crystal display elements.

Claims (7)

1. A diamine represented by the following formula [1].
   

   

   (In Formula [1], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, and R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and any hydrogen atom of the benzene ring is And may be substituted with a monovalent organic group.)
2. A polymer obtained from a diamine component containing a diamine having a structure represented by the following formula [2].
   

   

   (In Formula [2], Y ¹ is a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, O or a monovalent organic group, R ³ is an alkylene group having 1 to 3 carbon atoms, * represents a site bonded to another group, and any hydrogen atom of the benzene ring is (It may be substituted with a monovalent organic group.)
3. It is obtained from the diamine component containing the diamine which has a structure represented by following formula [3], The polymer of Claim 2 characterized by the above-mentioned.
   

   

   (In Formula [3], Y ¹ and Y ² are each independently a single bond, —O—, —S—, —COO— or —OCO—, and R ¹ and R ² are each independently —H, —OH, ═O or a monovalent organic group, R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, and * is a site bonded to another group In addition, any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)
4. The polymer according to claim 2 or 3, wherein the polymer is at least one selected from a polyimide precursor containing a structural unit represented by the following formula [4] and a polyimide that is an imide compound thereof.
   

   

   (In Formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent derived from a diamine having a structure represented by Formula [2] or Formula [3]. R ⁵ and R ^{6 each} represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and A ¹ and A ² each independently represent a hydrogen atom or a carbon atom having 1 to 5 carbon atoms. Represents an alkyl group, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.)
5. A liquid crystal aligning agent comprising the polymer according to any one of claims 2 to 4 and an organic solvent.
6. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 5.
7. A liquid crystal display element comprising the liquid crystal alignment film according to claim 6.