TWI766889B - Diamine, polymer, liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

(式[1]中，Y¹ 及Y² 係分別獨立為單鍵、-O-、-S-、-COO-或-OCO-，R¹ 及R² 係分別獨立為-H、-OH、=O或一價的有機基，R³ 及R⁴ 係分別獨立為碳原子數1~3的伸烷基，又，苯環的任意的氫原子可被一價的有機基所取代)。The present invention relates to a diamine having a structure 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, 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 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 in a liquid crystal display element, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element.

Today, liquid crystal display elements are widely used as display parts of personal computers, mobile phones, television developing machines, 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 for applying an electric field to the liquid crystal layer, and a device for controlling the alignment of liquid crystal molecules in the liquid crystal layer. Liquid crystal alignment films, thin film transistors (TFTs) for switching electrical signals supplied to pixel electrodes, and the like. Among them, the liquid crystal alignment film is formed by adding a solution of polyimide (also referred to as "polyimide"), which is a polyimide precursor, or polyimide of the imide compound. The polyimide-based liquid crystal aligning agent is coated on a substrate to form a film.

In recent years, with the progress of high performance and large area of liquid crystal display elements, power saving of display devices, etc., in addition to these, in order to be used in various environments, the characteristics required for liquid crystal alignment films are also increasing. become strict. Therefore, by changing the structure of polyamide or polyimide, adding blends or additives of polyamide or polyimide with different characteristics, etc., in addition to improving liquid crystal alignment or electrical properties In addition to the above, the control of the pretilt angle and the like are also performed.

As an example of the method of improving the characteristics of a liquid crystal alignment film, a diamine having a novel structure to which a raw material of polyamic acid is applied is 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, and by using the liquid crystal aligning agent, a liquid crystal that is excellent in voltage retention and can reduce charge accumulation can be provided display element.

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

[Prior Art Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2010/053128

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a novel diamine for realizing the improvement of the characteristics of a liquid crystal display element, a polymer for use in a liquid crystal display element, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element .

As a result of intensive research by the present inventors, it was found that, when a polymer obtained by using a specific diamine is applied to a liquid crystal display element, it is extremely effective in reducing flicker (flicker/blinking) at the initial stage of driving. this invention. Furthermore, the diamine of the present invention described later is a novel compound not described in the literature.

The diamine of the present invention which achieves the above object is characterized 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, 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 may be substituted by a monovalent organic group).

The polymer of this invention which achieves the said objective is obtained from the diamine component containing the diamine which has the structure represented by following formula [2], It is characterized by the above-mentioned.

(In formula [2], Y ¹ is a single bond, -O-, -S-, -COO- or -OCO-, and R ¹ and R ² are independently -H, -OH, =O or monovalent, respectively. In the organic group, R ³ represents an alkylene group having 1 to 3 carbon atoms, * represents a bonding site with other groups, and any hydrogen atom of the benzene ring may be substituted by a monovalent organic group).

Moreover, it is preferable that the said polymer is obtained from the diamine component containing the diamine which has a structure represented by 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, * represents a site where other groups are bonded, and an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group).

In addition, the above-mentioned polymer is selected from a polyimide precursor including a structural unit represented by the following formula [4] and a polyimide compound of the polyimide compound. At least one of the imines is preferred.

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

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

The liquid crystal alignment film of the present invention which achieves the above object is characterized by being obtained from the above-mentioned liquid crystal alignment agent.

The liquid crystal display element of this invention which achieves the said objective is equipped with the said liquid crystal alignment film, It is characterized by the above-mentioned.

According to the present invention, novel diamines for realizing the improvement of the characteristics of liquid crystal display elements, polymers for liquid crystal display elements, liquid crystal alignment agents and liquid crystal alignment films, and liquid crystal display elements can be provided.

[The best form of implementing the invention]

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, 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 may be substituted by a monovalent organic group).

In formula [1], examples of the monovalent organic group include: a hydrocarbon group; a hydroxyl group, a carboxyl group, a hydrocarbon group including a hydroxyl group, a thiol group, or a carboxyl group; a bonding group via an ether bond, an ester bond, an amide bond, or the like A hydrocarbon group to be linked; a hydrocarbon group containing a silicon atom; a halogenated hydrocarbon group; an amine group; Furthermore, the hydrocarbon group may be any of straight chain, branched chain and cyclic chain, and may be saturated hydrocarbon or unsaturated hydrocarbon. Also, a part of the hydrogen atoms of the hydrocarbon group may be replaced by a carboxyl group, a hydroxyl group, A thiol group, a silicon atom, a halogen atom, etc. are substituted, and it is also possible to connect by a bonding group such as an ether bond, an ester bond, and an amide bond.

In addition, the alkylene group having 1 to 3 carbon atoms may be any of straight chain, branched chain and cyclic chain. Specifically, methylene group, ethylidene group, n-propylidene group, isopropylidene group, cyclopropylene group, 1-methyl-cyclopropylene group, 2-methyl-cyclopropylene group can be mentioned. , 1,1-dimethyl-n-propylidene, 1,2-dimethyl-n-propylidene, 2,2-dimethyl-n-propylidene, 1-ethyl-n- Propylene, 1,2-Dimethyl-cyclo-extended propyl, 2,3-dimethyl-cyclo-extended propyl, 1-ethyl-cyclo-extended propyl, 2-ethyl-cyclo-extended propyl, 1,1,2-Trimethyl-n-propylidene, 1,2,2-trimethyl-n-propylidene, 1-ethyl-1-methyl-n-propylidene, 1- Ethyl-2-methyl-n-extended propyl, 2-n-propyl-cycloextended propyl, 1-isopropyl-cycloextended propyl, 2-isopropyl-cycloextended propyl, 1, 2,2-Trimethyl-cycloextended propyl, 1,2,3-trimethyl-cycloextended propyl, 2,2,3-trimethyl-cycloextended propyl, 1-ethyl-2- Methyl-cycloextended propyl, 2-ethyl-1-methyl-cycloextended propyl, 2-ethyl-2-methyl-cycloextended propyl and 2-ethyl-3-methyl-cycloextended Propyl etc.

Furthermore, a monovalent organic group or an alkylene group with 1 to 3 carbon atoms can be selected in various ways according to the application.

As a specific example of the diamine represented by formula [1], the diamine represented by following formula [5-1] - formula [5-13] can be illustrated, but it is not limited to these.

Furthermore, in the formula [5-3], Boc represents a group (tert-butoxycarbonyl group) shown below.

<Synthesis method of diamine>

Next, the main synthesis method of the diamine of the present invention will be described Bright. Incidentally, the method described below is a synthesis example, but is not limited to this.

The diamine of the present invention can be obtained by converting a nitro group into an amine group by reducing a dinitro compound as represented by the following reaction formula. Furthermore, as an example described in the following reaction formula, it is a diamine in which the hydrogen atom of the benzene ring and the saturated hydrocarbon moiety is not substituted by a halogen atom such as a fluorine atom or a monovalent organic group other than an amine group.

(In the above reaction formula, Y ¹ and Y ² are independently a single bond, -O-, -S-, -COO- or -OCO-, R ¹ and R ² are 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 any hydrogen atom of the benzene ring may be substituted by a monovalent organic group).

The method for reducing the dinitro compound is not particularly limited, but palladium-carbon, platinum oxide, Raj's nickel, platinum black, rhodium-alumina, platinum sulfide carbon, etc. are used as catalysts in ethyl acetate, toluene, A method of reducing with hydrogen, hydrazine, hydrogen chloride, etc. in a solvent such as tetrahydrofuran, dioxane, or alcohol. If necessary, it can also be carried out under pressure using an autoclave or the like. On the other hand, when an unsaturated bond site is included in the structure of the substituent that replaces the hydrogen atom of the benzene ring or the saturated hydrocarbon moiety, when palladium carbon, platinum carbon or the like is used, This unsaturated bond site may be reduced to become a saturated bond, so the reduction conditions using reduced iron or transition metals such as tin and tin chloride as catalysts are preferable.

The above reaction system can be carried out in the presence of a base. The base to be used is not particularly limited as long as it can be synthesized, and examples thereof include inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium Organic bases such as methylaminopyridine, trimethylamine, triethylamine, tributylamine, etc. In addition, depending on the situation, when a palladium catalyst such as dibenzylideneacetone palladium or diphenylphosphinoferrocene palladium or a copper catalyst or the like is used in combination, the yield can be improved.

The diamine of the present invention obtained in this way can be used as a polyimide precursor, polyimide, polyurea, polyamide, etc. known as "polymer") raw materials. This polymer system can be used as a liquid crystal aligning agent by dissolving it in a predetermined organic solvent, for example, but it is not limited to this use. Hereinafter, the polymer containing the diamine represented by Formula [1] in this structure is demonstrated.

<polymer>

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

(In formula [2], Y ¹ is a single bond, -O-, -S-, -COO- or -OCO-, and R ¹ and R ² are independently -H, -OH, =O or monovalent, respectively. In the organic group, R ³ represents an alkylene group having 1 to 3 carbon atoms, * represents a bonding site with other groups, and any hydrogen atom of the benzene ring may be substituted by a monovalent organic group).

The structure represented by the formula [2] derived from the diamine component of such a polymer is preferably one having the 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, * represents a site where other groups are bonded, and an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group).

Here, as the derivative of the diamine of the present invention, a diamine having a structure in which two or more of the above-mentioned diamines are linked together, or a diamine having the above-mentioned diamine linked through the above-mentioned Y ¹ or Y ² can be mentioned. Structure of the diamine. Moreover, in addition to Formula [2], the structure derived from a diamine component may contain the structure derived from another diamine (it mentions later).

Further, as the monovalent organic group or the alkylene group having 1 to 3 carbon atoms in the formulas [2] and [3], the same ones as those of the formula [1] can be mentioned.

In addition, the polymer of the present invention is selected from the group consisting of a polyimide precursor including a structural unit represented by the following formula [4] and a polymer of the imide compound from the viewpoint of use as a liquid crystal aligning agent. At least one kind of imide is preferred.

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

In formula [4], examples of the alkyl group having 1 to 5 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, s-pentyl, t-pentyl, etc.; Examples of the alkenyl group having 2 to 5 carbon atoms include vinyl, allyl, 1-propenyl, and 1-butane. Alkenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, etc.; as an alkynyl group having 2 to 5 carbon atoms , for example, an ethynyl group, a 1-propynyl group, a 2-propynyl (propargyl) group, a 3-butynyl group, a pentynyl group, and the like are mentioned. Among them, R ⁵ and R ⁶ are preferably hydrogen atoms, methyl groups or ethyl groups, and more preferably hydrogen atoms or methyl groups, from the viewpoint that the imidization reaction is easily carried out during heating, From the viewpoint of liquid crystal alignment, A ¹ and A ² are preferably hydrogen atoms or methyl groups.

The structure is not particularly limited as long as X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative. In addition, X ¹ can be adjusted according to the degree of the solubility of the polymer in the solvent, the coatability of the liquid crystal alignment agent, the alignment of the liquid crystal when the liquid crystal alignment film is formed, the voltage retention rate, the accumulated charge, etc. Appropriately selected, one type of the same polymer may be used, or two or more types may be mixed.

Not only tetracarboxylic dianhydride, but also tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester compound or tetracarboxylic acid dialkyl ester dihalogenation compound of the tetracarboxylic acid derivative can be used for X ¹ compound. As the tetracarboxylic dianhydride or the derivative, at least one selected from the tetracarboxylic dianhydride represented by the following formula [6] or the derivative is preferably used.

In 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 formulae [V ¹ -1] to [V ¹ -44].

In formula [V ¹ -1] to formula [V ¹ -4], R ⁷ to R ²⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkene having 2 to 6 carbon atoms. A group, an alkynyl group having 2 to 6 carbon atoms, a fluorine atom-containing monovalent organic group having 1 to 6 carbon atoms, or a phenyl group may be the same or different. From the viewpoint of liquid crystal alignment, 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.

As a specific structure of Formula [ ^V1-1 ], the structure represented by following formula [ ^V1-1-1 ] - Formula [ ^V1-1-6 ] is mentioned. The structure represented by the following formula [V ¹ -1-1] is particularly preferable from the viewpoint of the liquid crystal alignment and the sensitivity of the photoreaction.

In formula [4], W ¹ is not particularly limited as long as it is a divalent organic group derived from a diamine having a structure represented by formula [2] or formula [3], and 2 may be present in combination. above types. Moreover, W ¹ corresponds to the structure of the diamine component used in the present invention, and contains a specific diamine having a structure represented by the formula [1] (for example, selected from the following formulas [W ¹ -1] to At least one diamine in the group of compounds represented by [W ¹ -13]).

Furthermore, in the formula [W ¹ -3], Boc represents the group shown below (tert-butoxycarbonyl group).

However, all of W ¹ need not necessarily have a structure corresponding to the above-mentioned diamine. A part of W ¹ may contain a structure corresponding to a diamine (other diamine) other than the above-mentioned diamine. The structure corresponding to other diamines (hereinafter referred to as "structure W ² ") can be generalized as represented by the following formula [7]. Furthermore, as A ¹ and A ² in the following formula [7], the same ones as those of the formula [4] can be mentioned.

Furthermore, when the structure W ² represented by the formula [7] is illustrated, it is as represented by the following formulae [W ² -1] to [W ² -173].

Furthermore, 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] represents a tert-butoxycarbonyl group as shown below .

When the polyimide precursor containing the structural unit represented by the formula [4] also contains the structural unit represented by the formula [7], with respect to the sum of the formula [4] and the formula [7], the formula [4] The indicated structural unit is preferably 10 mol % or more, more preferably 20 mol % or more, and particularly preferably 30 mol % or more.

The molecular weight of the polyimide precursor or polyimide of the polymer of the present invention, when obtaining a liquid crystal alignment film from a liquid crystal alignment agent containing the polymer, the strength of the coating film (liquid crystal alignment film), the strength of the coating film, and the For the workability during formation and the uniformity of the coating film, the weight average molecular weight measured by GPC (Gel Permeation Chromatography) method is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and 10,000 to 100,000. better.

<Production method of polymer>

Next, the main manufacturing method of the polymer of this invention is demonstrated. In addition, the method demonstrated below is a manufacturing example, and is not limited to this.

For example, if the polymer containing the structural unit represented by the formula [4] is a polyimide precursor of polyimide, the above-mentioned polymer can be obtained by combining tetracarboxylic dianhydride and dicarboxylic acid tetracarboxylic acid derivative. obtained by the reaction of the amine component. borrow When the polyamic acid is obtained by this reaction, a known synthesis method can be used. This synthesis method is a method of reacting a tetracarboxylic dianhydride and a diamine component in an organic solvent. The above-mentioned method is advantageous in that it can be carried out relatively easily in an organic solvent and does not generate by-products.

The organic solvent used in the above-mentioned reaction is not particularly limited as long as the resulting polyamic acid (polymer) can be dissolved, and examples thereof include N,N-dimethylformamide, N,N- Dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, aridine , dimethyl sulfite, hexamethyl sulfoxide, γ-butyrolactone, isopropanol, methoxymethyl pentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone Ketone, Methyl Isoamyl Ketone, Methyl Isopropyl Ketone, Methyl Cellosolve, Ethyl Cellosolve, Methyl Cellosolve Acetate, Ethyl Cellosolve Acetate, Butyl Carbide Alcohol, Ethyl Carbitol, 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, butyric acid Butyl ester, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether , Cyclohexanone, Ethylene carbonate, Propylene carbonate, Emulsion Methyl Acetate, Ethyl Lactate, Methyl Acetate, Ethyl Acetate, N-Butyl Acetate, Propylene Glycol Monoethyl Ether, Methyl Pyruvate, Ethyl Pyruvate, Methyl 3-Methoxypropionate, 3 -Methyl ethyl ethoxypropionate, Ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3-methylpropionate Butyl oxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethylpropionamide, 3-ethoxy -N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, etc. These systems may be used alone or in combination. Moreover, even if it is a solvent which cannot dissolve a polyamic acid (polymer), in the range in which the produced polyamic acid does not precipitate, you may mix and use it with the said organic solvent. In particular, the moisture in the organic solvent may inhibit the polymerization reaction and further hydrolyze the produced polyamic acid. Therefore, it is preferable to use the organic solvent that is dehydrated and dried as much as possible.

When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, the following method may be mentioned: stirring to disperse or dissolve the diamine component in the organic solvent to obtain a solution, and directly adding the tetracarboxylic acid dihydrate to the solution. Anhydride, or a method of dispersing or dissolving tetracarboxylic dianhydride in an organic solvent and then adding it; a method of dispersing or dissolving tetracarboxylic dianhydride in an organic solvent to obtain a solution, and adding a diamine component to the aforementioned solution; The method of adding a tetracarboxylic dianhydride and a diamine component alternately, etc., can use any of these methods. In addition, when the tetracarboxylic dianhydride or diamine component is composed of a plurality of compounds, it may be allowed to react in a premixed state, or may be reacted individually in sequence, and further reacted individually with low molecular weight. The body is mixed and reacted to make a high molecular weight body.

At this time, the temperature of the polycondensation can be selected from -20°C to 150°C Arbitrary temperature, Preferably it is the range of -5 degreeC - 100 degreeC. In addition, the polycondensation reaction system 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, making it difficult to uniformly stir. Therefore, the total concentration of the tetracarboxylic dianhydride and the diamine component in the reaction solution is preferably set to 1% by mass to 50% by mass, and more preferably set to 5% by mass to 30% by mass. The initial stage of the reaction may be carried out at a high concentration, and an organic solvent may be added after that.

In the polymerization reaction of polyamic acid, the ratio of the total moles of tetracarboxylic dianhydride to the total moles of diamine components (total moles of tetracarboxylic dianhydride/total moles of diamine components) ) is preferably 0.8 to 1.2. As in the general polycondensation reaction, the molecular weight of the polyamic acid produced is increased as the molar ratio is closer to 1.0.

If the polymer containing the structural unit represented by the formula [4] is a polyamide, it can be reacted with a tetracarboxylic acid diester diacid chloride and a diamine component, or by a tetracarboxylic acid diester and a diamine component. The diamine component is obtained by reacting it in the presence of a suitable condensing agent or a base. Alternatively, it can be obtained by synthesizing polyamic acid in advance according to the above-mentioned method, and then esterifying the carboxylic acid in the polyamic acid by polymer reaction.

Specifically, for example, tetracarboxylic acid diester diacid chloride and diamine can be reacted for 30 minutes at -20°C to 150°C, preferably 0°C to 50°C in the presence of a base and an organic solvent. ~24 hours, preferably 1 hour to 4 hours to synthesize the polyamide.

As the base system, arsenic, triethylamine, 4-dimethylaminopyridine, etc. can be used, and arsenic is preferable in order to allow the reaction to proceed mildly. alkaline The addition amount is preferably 2 to 4 times mol relative to the tetracarboxylic acid diester diacyl chloride from the viewpoint of an amount that can be easily removed and a high molecular weight product is easily obtained.

In addition, when the tetracarboxylic acid diester and the diamine component are polycondensed in the presence of a condensing agent, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3 can be used as the base. -(3-Dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium , O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylurea tetrafluoroborate, O-(benzotriazol-1-yl)-N,N, N',N'-tetramethylurea hexafluorophosphate, (2,3-dihydro-2-sulfanyl-3-benzoxazolyl) diphenylphosphonate, 4-(4,6-diphenyl) Methoxy-1,3,5-triazin-2-yl)4-methoxymorpholine hydrochloride n-hydrate, etc.

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

The solvent used in the above-mentioned reaction can be carried out using the same solvent as the solvent used in the synthesis of the polyamic acid shown above, but in terms of the solubility of monomers and polymers, N- Methyl-2-pyrrolidone and γ-butyrolactone are preferable, and these may be used alone or in combination of two or more. The concentration at the time of synthesis is difficult to cause precipitation of the polymer, and it is easy to obtain a high-molecular-weight body. The total concentration in the reaction solution is preferably 1% by mass to 30% by mass, and 5% by mass to 20% by mass For better. In addition, in order to prevent the hydrolysis of the tetracarboxylic diester diacyl chloride, the solvent used for the synthesis of the polyamic acid ester is preferably in a dehydrated state as much as possible, and it is preferable to prevent the mixing of foreign gas in a nitrogen environment.

When 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. Acid dehydration and ring closure can be obtained. In this polyimide, the dehydration ring closure rate (imidation rate) of the amide acid group does not necessarily have to be 100%, and can be arbitrarily adjusted according to the application and purpose.

As a method of imidizing a polyamic acid, thermal imidization in which a solution of polyamic acid is directly heated, or catalytic imidization in which a catalyst is added to a solution of polyamic acid can be mentioned. Wait.

The temperature during thermal imidization of the polyamic acid in the solution is 100°C to 400°C, preferably 120°C to 250°C, so that the water generated by the imidization reaction is discharged to the outside of the system. It is better to do it at the same time.

The catalytic imidization of polyamide acid can be carried out by adding alkaline catalyst and acid anhydride to the solution of polyamide acid, at -20℃~250℃, preferably at 0℃~180℃. Stir to proceed. The amount of the alkaline catalyst is 0.5 mol times to 30 mol times of the amide acid group, preferably 2 mol times to 20 mol times, and the amount of the acid anhydride is 1 mol times to 50 mol times of the amide acid group. Molar times, preferably 3 mol times to 30 mol times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like, and among these, pyridine-based catalysts are preferred because they have an appropriate basicity to allow the reaction to proceed. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic dianhydride, and the like. Among them, when acetic anhydride is used, purification after completion of the reaction is easy to perform. by catalytic imide The rate of imidization of Zn can be controlled by adjusting the amount of catalyst, reaction temperature and reaction time.

Moreover, as mentioned above, polyimide can also be obtained by heating a polyimide at a high temperature to promote dealcoholization and to close the ring.

In addition, when recovering the resulting polyamic acid, polyamic acid ester, and polyimide from polyimide precursors such as polyamic acid and polyamic acid ester, or from the reaction solution of polyimide, The reaction solution may be poured into a poor solvent and precipitated. Examples of poor solvents used for precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, water, and the like. The polyimide precursor or polyimide-based which has been put into a poor solvent and precipitated can be recovered by filtration, and then dried under normal pressure or reduced pressure, at normal temperature or under heating. In addition, if the polyimide precursor or polyimide recovered by precipitation is redissolved in an organic solvent and the operation of reprecipitation and recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, and hydrocarbons. When three or more types of poor solvents selected from these are used, the purification efficiency is further improved, which is preferable.

The polymer of the present invention obtained in this manner can be dissolved in a designated organic solvent and used as a liquid crystal aligning agent. The liquid crystal alignment agent is a liquid crystal alignment film used for controlling the alignment of liquid crystal molecules in 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 alignment agent>

The polymer contained in the liquid crystal aligning agent of the present invention is a polymer obtained from a diamine component containing a diamine having a structure represented by the formula [2] derived from the above-mentioned diamine component. Moreover, it is preferable that this liquid crystal aligning agent contains the polymer which has the structure represented by Formula [3] derived from the said diamine component. Moreover, it is preferable that this polymer is at least 1 sort(s) chosen from the polyimide precursor which contains the structural unit represented by Formula [4], and the polyimide compound of this.

However, the polymers contained in the liquid crystal aligning agent of the present invention may all be the polymers of the present invention, and the polymers of the present invention may also contain two kinds of polymers as long as the effects described in the present invention can be exhibited. different structures above. Alternatively, in addition to the polymer of the present invention, another polymer, that is, a polymer not having a divalent group represented by formula [2] or formula [3] may be contained. Examples of other types of polymers include polyamide, polyimide, polyamide, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polycondensate Aldehyde, polystyrene or derivatives thereof, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, 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 relative to the total polymer components is preferably 5% by mass or more, and an example thereof includes 5% by mass to 95% by mass. quality%. The proportion of the polymer of the present invention can be appropriately selected according to the characteristics of the liquid crystal alignment agent or the liquid crystal alignment film.

The liquid crystal alignment agent of the present invention is used for the production of a liquid crystal alignment film, and is generally in the form of a coating solution from the viewpoint of forming a uniform thin film. The liquid crystal alignment agent of the present invention is also composed of the aforementioned polymer. It is preferable to separate it into a coating liquid with an organic solvent in which the polymer component is dissolved. At this time, the concentration of the polymer in the liquid crystal aligning agent can be appropriately changed according to the thickness setting of the coating film to be formed. In terms of forming a uniform and defect-free coating film, 1 mass % or more is preferable, and 10 mass % or less is preferable in terms of storage stability of the solution. The concentration of a particularly preferable polymer is 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 dissolves the polymer. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidine Ketone, dimethyl sulfoxide, gamma-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2 -Pentanone, etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are preferably used. Incidentally, the organic solvent systems exemplified here may be used alone or in combination. Furthermore, even if it is a solvent incapable of dissolving a polymer, as long as the produced polymer does not precipitate, it can be mixed with an organic solvent and used.

Moreover, as the organic solvent contained in the liquid crystal aligning agent, a mixed solvent is generally used, which is used in addition to the above-mentioned solvents, and is also used in combination to improve the coatability or the surface smoothness of the coating film at the time of coating the liquid crystal aligning agent. Even the mixed solvent in the liquid crystal aligning agent of the present invention is suitable for use. Specific examples of the organic solvent to be used in combination are given below, but are not limited to these examples.

For example, ethanol, isopropanol, 1-butanol, 2-butanol, Isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2- Butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol Alcohol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methyl cyclohexanol, 1,2-ethylene glycol, 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 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, propylidene carbonate, ethylidene 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-(butoxy) Ethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol Alcohol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol Alcohol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetic acid Esters, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoacetate Ethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxy Propionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate ester, isoamyl lactate, etc.

Moreover, in addition to the above-mentioned solvent, for example, the solvent represented by following formula [S-1] - formula [S-3] can also be used.

In formula [S-1] and formula [S-2], R ²⁸ and R ²⁹ represent an alkyl group having 1 to 3 carbon atoms. As a C1-C3 alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group etc. are mentioned, for example. In addition, in 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.

Among the organic solvents used in combination, 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxyl -4-methyl-2-pentanone, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether are preferred. Types and contents of such solvents The system can be appropriately selected according to the coating device of the liquid crystal alignment agent, coating conditions, coating environment, and the like.

Moreover, it is preferable that these solvent systems are 20 mass % - 99 mass % of the whole solvent contained in a liquid crystal aligning agent. Among them, 20% by mass to 90% by mass is preferable. More preferably, it is 20 mass % - 70 mass %.

The liquid crystal aligning agent of this invention may additionally contain components other than a polymer component and an organic solvent in the range which does not impair the effect of this invention. Examples of such additional components include an adhesion adjuvant for improving the adhesion between a liquid crystal alignment film and a substrate, or between a liquid crystal alignment film and a sealing material, and a crosslinking for improving the strength of the liquid crystal alignment film. agents, dielectric or conductive substances used to adjust the dielectric constant or resistance of the liquid crystal alignment film. Specific examples of these additional components are as disclosed in various publications in the well-known literature on liquid crystal aligning agents, and to show one example, paragraphs [0105] to [0116] of International Publication No. 2015/060357 can be cited. The ingredients disclosed in the paragraph, etc.

<Liquid crystal alignment film>

The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. As an example of a method for obtaining a liquid crystal alignment film from a liquid crystal alignment agent, the liquid crystal alignment agent in the form of a coating solution is applied to a substrate, dried, and then fired by a rubbing treatment method or a photo-alignment treatment method. A method of applying an alignment treatment to the resulting film.

The substrate on which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate with high transparency, and a glass-based substrate may be used. In addition to boards and silicon nitride substrates, plastic substrates such as acrylic substrates or polycarbonate substrates are used. In this case, it is preferable to use a substrate for forming ITO electrodes or the like for driving the liquid crystal from the viewpoint of simplification of the process. In addition, as for the reflective liquid crystal display element, if it is only a single-sided substrate, an opaque material such as a silicon wafer can be used, and a light-reflecting material such as aluminum can also be used as the electrode in this case.

The coating method of the liquid crystal alignment agent is not particularly limited, and industrially, it is usually screen printing, lithographic printing, flexographic printing, inkjet method, and the like. As another coating method, there exist a dipping method, a roll coating method, a slit coating method, a spinner method, a spray method, etc., and these can also be used according to the objective.

Firing after coating the liquid crystal aligning agent on the substrate can be carried out at 50°C to 300°C, preferably 80°C to 250°C by heating means such as a hot plate, hot air circulation furnace, and infrared furnace. Evaporated to form a coating film (liquid crystal alignment film). If the thickness of the coating film formed after firing is too thick, it will be 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 decrease, so it is preferable to use 5 nm to 300 nm, preferably 10 nm to 100 nm. When aligning a liquid crystal horizontally or diagonally, the coating film after baking is processed by rubbing, polarized ultraviolet irradiation, or the like.

After apply|coating a liquid crystal aligning agent to a board|substrate, it bakes by evaporating a solvent by heating means, such as a hotplate, a thermal cycle type oven, and an IR (infrared) type oven. The drying and firing steps after coating the liquid crystal aligning agent can select any temperature and time. Usually, in order to sufficiently remove the contained solvent, firing at 50°C to 120°C for 1 minute to 10 minutes, and then, Firing 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 liquid crystal display element of a lateral electric field method such as an IPS method or an FFS method, and is particularly useful as a liquid crystal alignment film for a liquid crystal display element of the FFS method.

<Liquid crystal display element>

The liquid crystal display element of the present invention is provided with the above-mentioned liquid crystal alignment film, and after obtaining the substrate with the liquid crystal alignment film obtained from the above-mentioned liquid crystal alignment agent, a liquid crystal cell is produced by a known method, and the liquid crystal crystal is used. cells to make components. As an example, it is a liquid crystal display element including a liquid crystal cell having two substrates arranged to face each other, a liquid crystal layer provided between the substrates, and a liquid crystal layer provided between the substrates and the liquid crystal layer. The liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention.

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

In addition, the liquid crystal alignment film is formed by coating the liquid crystal alignment agent of the present invention on the substrate, followed by firing, 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 crystal and smectic liquid crystal, among which nematic liquid crystal is preferred, and positive liquid crystal material or negative liquid crystal material can also be used. Type fluid any of the crystalline materials. Specifically, for example, MLC-2003, MLC-6608, MLC-6609, MLC-3019, MLC-2041, and MLC-7026-100 manufactured by Merck can be used.

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

Next, a UV-curable sealing material, for example, is arranged at a specified position on one of the two substrates on which the liquid crystal alignment film has been formed, and then liquid crystals are arranged at specified positions on the surface of the liquid crystal alignment film. The liquid crystal alignment film is attached to another substrate in an opposite manner and pressure-bonded, and the liquid crystal is pushed away and diffused to the front and rear of the liquid crystal alignment film.

Alternatively, as a step after forming a liquid crystal alignment film on a substrate, when a sealing material is provided at a predetermined position on one substrate, an opening that can be filled with liquid crystal from the outside is provided in advance, and the substrate is bonded without arranging the liquid crystal, and the sealing material is passed through the sealing material. The provided opening is injected with a liquid crystal material into the liquid crystal cell, and the opening is sealed with an adhesive to obtain a liquid crystal cell. Next, for the injection of the liquid crystal material, a vacuum injection method or a method utilizing a capillary phenomenon in the atmosphere may be used.

Even with any of the above methods, in order to ensure The space filled with the intracellular liquid crystal material is preferably by means of providing columnar protrusions on one substrate, dispersing spacers on one substrate, mixing spacers in a sealing material, or a combination of these.

Next, set up the polarizer. Specifically, it is preferable to stick a pair of polarizers on the surfaces on the opposite side to the liquid crystal layers of the two substrates.

Furthermore, the liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above descriptions, as long as the liquid crystal alignment agent of the present invention is used, and other well-known methods can also be used. The steps from a liquid crystal aligning agent to obtaining a liquid crystal display element are also disclosed in many documents, in addition to, for example, paragraphs [0148] to [0149] of JP 2015-135393 A.

As described above, since the liquid crystal display element produced using the liquid crystal aligning agent of the present invention is excellent in reliability, it can be suitably used for large-screen and high-definition liquid crystal televisions and the like.

[Example]

The details of the production method of the present invention will be described below by citing an experimental method for examining the composition or mixing ratio of raw materials and the results thereof, as well as examples of typical production methods, etc., but the present invention is not limited to these. in the examples.

Furthermore, the abbreviations of compounds or solvents, and the methods of property evaluation are as follows.

<Organic solvent>

NMP: N-methyl-2-pyrrolidone

NEP: N-ethyl-2-pyrrolidone

GBL: gamma-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 on carbon

DMSO: dimethyl sulfoxide

THF: Tetrahydrofuran

<Additive>

LS-4668: 3-Glycidoxypropyltriethoxysilane

LS-3150: 3-Aminopropyltriethoxysilane

< Measurement of ¹ H-NMR>

Apparatus: Varian NMR system 400NB (400MHz) (manufactured by Varian), and JMTC-500/54/SS (500MHz) (manufactured by JEOL)

Assay solvent: CDCl ₃ (deuterated chloroform), DMSO-d ₆ (deuterated dimethyl sulfoxide)

Reference material: TMS (tetramethylsilane) (δ: 0.0ppm, 1H) and CDCl ₃ (δ: 77.0ppm, 1 ³ C)

<Molecular weight determination of polyimide precursor and imidized polymer>

The measurement was performed under the following conditions using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and columns (KD-803, KD-805) (manufactured by Shodex Corporation).

Column temperature: 50℃

Solvent: N,N'-dimethylformamide (as an additive, lithium bromide-hydrate (LiBr·H ₂ O) is 30 mmol/L (liter), phosphoric anhydride crystal (o-phosphoric acid) is 30 mmol/L, Tetrahydrofuran (THF) is 10ml/L)

Flow rate: 1.0ml/min

Standard sample for calibration line preparation: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, and 30,000, Tosoh Co., Ltd. Company) and polyethylene glycol (molecular weight: about 12,000, 4,000, and 1,000, manufactured by Polymer Laboratories)

<Viscosity measurement>

In the synthesis examples and comparative synthesis examples to be described later, the viscosity of the polyamide acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL and a conical rotor TE-1 (1°34). ', R24) down to measure.

<Synthesis of diamine compound (DA-1)>

In a 2L (liter) four-necked flask, BNPU (50g, 140mmol), potassium carbonate (44.4g, 320mmol), and NMP (1000g) were charged, the temperature was raised to 50°C under wing stirring, and 40°C was added dropwise over 10 minutes. % Aqueous glyoxal solution (46.7 g, 320 mmol) and stirred for 12 hours. Since the raw material remained by HPLC (high performance liquid chromatography), potassium carbonate (44.4 g, 320 mmol) and a 40% glyoxal aqueous solution (46.7 g, 320 mmol) were further added, and stirred for 12 hours to obtain compound [A] . After confirming the disappearance of the raw materials, the salt was filtered, and sulfuric acid (15 g) was added dropwise, and the solution was made acidic, followed by stirring at 70° C. for 24 hours. After confirming completion of the reaction by HPLC, methanol (1000 g) and pure water (1000 g) were added, and the mixture was cooled at 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 crystal (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% aqueous type), characteristic egret activated carbon (3.5 g), and dioxane (350 g) was pressurized under hydrogen The mixture was stirred at 60°C for 8 hours. After completion of the reaction, the catalyst was filtered and concentrated, 2-propanol (350 g) was added, and the mixture was stirred at 5°C for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (70 g), and then dried to obtain powder crystals DA-1 (27 g in yield, 92% in yield).

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]

The obtained DA-1 (3.38 g, 10.0 mmol) was added to a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, followed by adding 28.8 g of NMP, and stirring to dissolve it while feeding nitrogen. While stirring the solution, add After adding CA-1 (0.87 g, 4.0 mmol), CA-2 (1.08 g, 5.5 mmol), and NMP 9.6 g, it was further stirred at 50° C. for 12 hours to obtain the following Table 1. Polyamide solution (PAA-A1).

[Synthesis Example 2 to Synthesis Example 5]

It was carried out in the same manner as in Synthesis Example 1, except that the diamine component, the tetracarboxylic acid component, and NMP (N-methyl-2-pyrrolidone) shown in the following Table 1 were used and the reaction temperatures were set respectively. The polyamic acid solutions (PAA-A2) and the polyamic acid solutions (PAA-B1) to (PAA-B3) shown in the following Table 1 were obtained.

[Examples 1 to 10 and Comparative Examples 1 and 2]

So that the solvent in the obtained liquid crystal aligning agent becomes the composition shown in the following Table 2 and the following Table 3, while stirring the polyamide solution obtained in Synthesis Example 1 to Synthesis Example 5, the solvent and additives are added, and then By stirring at room temperature for 2 hours, a liquid crystal aligning agent was obtained, respectively.

However, *1 to *3 in Table 2 and Table 3 are as follows.

*1: Indicates the introduction amount (parts by weight) of each polymer with respect to 100 parts by weight of the total polymer.

*2: Indicates the introduction amount (parts by weight) of each additive with respect to 100 parts by weight of the total polymer.

*3: Indicates the introduction amount (parts by weight) of the solvent 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 electrodes having a size of 30 mm×35 mm and a thickness of 0.7 mm was prepared. On the substrate, as the first layer, a structure that constitutes the counter electrode is formed. IZO electrodes with solid pattern. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by a CVD method was formed as a second layer. The thickness of the SiN film of the second layer is 500 nm, and it functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film is arranged as a third layer, thereby forming two pixels, a first pixel and a second pixel. The size of each pixel is 10 mm in length and 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-like shape formed by arranging a plurality of electrode elements having a “ㄑ” shape with a curved center portion, as shown in the figure ( FIG. 3 ) described in 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. The pixel electrode that forms each pixel is composed of a plurality of electrode elements having a “ㄑ” shape with a curved center portion arranged in a row. Therefore, the shape of each pixel is not a rectangle, but has the same shape as the electrode element that is curved in the center portion and has a thickness similar to that of the electrode element. The shape of the "ㄑ" character of the body is similar. Further, each pixel is divided up and down with the curved portion in the center as a boundary, and has a first area on the upper side and a second area on the lower side of the curved portion.

When the first region and the second region of each pixel are compared, the formation directions of the electrode elements constituting these pixel electrodes are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, in the first region of the pixel, the electrode elements of the pixel electrode are formed at an angle of +10° (clockwise), and in the second region of the pixel, The electrode elements of the pixel electrode are formed at an angle of -10° (clockwise). In addition, the first In the region and the second region, the directions of the in-plane switching (In-plane switching) of the liquid crystal induced by the application of the voltage between the pixel electrode and the counter electrode are opposite to each other. .

Next, after filtering the liquid crystal aligning agent with a 1.0 μm filter, spin-coating was performed on the above-mentioned substrate with electrodes and on the opposite substrate, on the back surface of which an ITO film was formed, and a columnar spacer having a height of 4 μm was formed. on the glass substrate. Next, after drying on a hot plate at 80° C. for 5 minutes, it was fired at 230° C. for 20 minutes to obtain a polyimide film having a thickness of 60 nm on each substrate. The polyimide film surface was subjected to a rubbing treatment with a rayon cloth under the conditions of a roller diameter of 120 mm, a roller rotation speed of 500 rpm, a platform moving speed of 30 mm/sec, and a rubbing cloth pressing pressure of 0.3 mm. Ultrasonic irradiation was performed in water for 1 minute, followed by drying at 80°C for 10 minutes.

Two types of substrates with liquid crystal alignment films as described above were used, and the respective rubbing directions were anti-parallel, and the periphery was sealed but the liquid crystal injection port was left to produce an empty cell with a cell gap of 3.8 μm. After the liquid crystal (Merck Corporation make, MLC-3019) was vacuum-injected into this empty cell at normal temperature, the injection port was sealed to obtain an antiparallel alignment liquid crystal cell. The obtained liquid crystal cell system constitutes an FFS mode liquid crystal display element. Then, the liquid crystal cell was heated at 120° C. for 1 hour, and was used for evaluation after being left to stand overnight.

<Evaluation of flicker level immediately after driving>

The fabricated liquid crystal cell is placed between two polarizers arranged in a way that the polarization axis is vertical, and the LED backlight is turned on under no applied voltage, and the brightness of the transmitted light is minimized to adjust the liquid crystal crystal. Cell configuration angle. Next, a V-T curve (voltage-transmittance curve) was measured while applying an AC voltage with a frequency of 30 Hz to the liquid crystal cell, and the AC voltage when the relative transmittance was 23% was calculated as a driving voltage.

For the measurement of flicker level, turn off the lighted LED backlight temporarily and place it in shading for 72 hours, then turn on the LED backlight again. The liquid crystal cell was driven for 60 minutes with an AC voltage of 30 Hz and the flicker amplitude was tracked. The flicker amplitude was read by a data collection/data logger switch unit 34970A (manufactured by Agilent technologies) connected to a photodiode and an I-V converter amplifier for the transmission of the LED backlight through the 2 polarizers and the liquid crystal cell in between Light. The flicker level is calculated according to the following formula [8].

Flicker level (%)={flicker amplitude/(2×z)}×100‧‧‧[8]

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

The evaluation of the flicker level is from the moment when the LED backlight is turned on and the AC voltage is applied to 60 minutes. When the flicker level is maintained at less than 3%, it is defined as "○" (it is not easy to cause flicker displacement just after the start of driving ( flicker shift)). When the flicker level reached 3% or more after 60 minutes, it was defined as "X" (flicker displacement is likely to occur immediately after the start of driving) and evaluated.

Furthermore, the evaluation of the flicker level according to the above-mentioned method was performed under the temperature condition of the state that the temperature of the liquid crystal cell was 23°C.

<Evaluation Result>

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

As shown in Table 4, the liquid crystal display elements using the liquid crystal aligning agents of Examples 1 and 2 were less likely to cause flicker displacement immediately after the start of driving.

[industrial availability]

The liquid crystal display element produced by using the liquid crystal aligning agent obtained from the diamine of the present invention can be used as a liquid crystal display device in which the flicker displacement immediately after the start of driving is reduced, and can be suitably used for TN (Twisted Nematic) liquid crystal display devices. Display elements, STN liquid crystal 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 and other types of display elements.

Claims (6)

A diamine characterized by being 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, the aforementioned monovalent organic group is: a hydrocarbon group that can be linked by a bonding group selected from an ether bond, an ester bond or an amide bond; or protected by a urethane system The inert group protected by the base, the aforementioned hydrocarbon group can be any one of straight chain, branched chain and cyclic chain, and can also be a saturated hydrocarbon or an unsaturated hydrocarbon, and a part of the hydrogen atom of the aforementioned hydrocarbon group can be further replaced by carboxyl, Hydroxyl group, thiol group, silicon atom and halogen atom are substituted, R ³ and R ⁴ are each independently an alkylene group with 1 to 3 carbon atoms, and any hydrogen atom of the benzene ring can be replaced by a monovalent organic group replaced). A polymer 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, the aforementioned monovalent organic group is: a hydrocarbon group that can be linked by a bonding group selected from an ether bond, an ester bond or an amide bond; or protected by a urethane system The inert group protected by the base, the aforementioned hydrocarbon group can be any one of straight chain, branched chain and cyclic chain, and can also be a saturated hydrocarbon or an unsaturated hydrocarbon, and a part of the hydrogen atom of the aforementioned hydrocarbon group can be further replaced by carboxyl, Substituted by hydroxyl group, thiol group, silicon atom and halogen atom, R ³ and R ⁴ are each independently an alkylene group having 1 to 3 carbon atoms, * represents a site where other groups are bonded, and a benzene ring Any hydrogen atom of can be replaced by a monovalent organic group). The polymer of claim 2, which is at least one selected from a polyimide precursor comprising a structural unit represented by the following formula [4] and a polyimide compound of the imide compound,

(In formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent organic group derived from a diamine having a structure represented by formula [2] or formula [3] Organic group, R ⁵ and R ⁶ represent a hydrogen atom or an alkyl group with 1 to 5 carbon atoms, and A ¹ and A ² independently represent a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, and 2 to 2 carbon atoms. 5 alkenyl or alkynyl with 2 to 5 carbon atoms). A liquid crystal alignment agent is characterized by containing the polymer of claim 2 or claim 3 and an organic solvent. A liquid crystal alignment film, which is characterized by being obtained from the liquid crystal alignment agent of claim 4. A liquid crystal display element is characterized by having the liquid crystal alignment film of claim 5.