TW201829752A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

The present invention comprises: a polymer obtained from an amine component including a diamine having a structure represented by formula [1]; and an organic solvent (in formula [1], Y1 represents a S atom or O atom, * represents a site that binds to another group, and any hydrogen atom in the benzene ring may be substituted with a monovalent organic group).

Description

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

The present invention relates to: novel diamines, polymers used in liquid crystal display elements, liquid crystal alignment agents and liquid crystal alignment films, and liquid crystal display elements.

Liquid crystal display devices have been widely used as a means to realize thin and lightweight display devices. The display characteristics of liquid crystal display elements are known to be greatly affected by the alignment of the liquid crystal, the size of the liquid crystal pretilt angle, the stability of the pretilt angle, and electrical characteristics. Therefore, the purpose of improving the display characteristics of these liquid crystal display elements is to The difference in the liquid crystal material used will be important for a liquid crystal alignment film that directly contacts the liquid crystal and determines its alignment state.

At present, the liquid crystal alignment film mainly uses a polyamic acid or polyimide resin solution as the liquid crystal alignment agent, and after coating these on a substrate, firing is performed, and the surface of the coating film is coated with fluorene or nylon. The cloth is formed by applying pressure rubbing, that is, performing a so-called rubbing treatment.

A method for preparing a liquid crystal alignment film from polyimide or a polyimide of a precursor thereof can use a coating resin solution and simple processes such as firing to obtain a liquid crystal alignment film having excellent heat resistance and solvent resistance. Since the coating film can be easily aligned with liquid crystals by using friction, it is still widely used in industry so far.

In addition, from the viewpoint of improving the display characteristics of liquid crystal display elements, various methods have been proposed for the structure of polyamic acid or polyimide, and resins with different characteristics have been mixed, and even improved liquid crystal alignment and improved Various technical proposals, such as the control of the inclination angle, the improvement of the stability, the improvement of the voltage holding ratio, or the improvement of the accumulation of charges that are not easily caused by the DC voltage, and the removal of the accumulated charges are easy. For example, Patent Document 1 proposes a polyimide resin having a specific repeating unit for the purpose of maintaining a high voltage holding ratio. Further, in Patent Document 2, for the afterimage phenomenon, a proposal is made to use a soluble polyfluoreneimide having a nitrogen atom other than the fluorenimine group to shorten the disappearance time of the afterimage.

However, with the advancement of higher performance of liquid crystal display elements, power saving of display devices, and improvement of durability in various environments, the voltage retention rate in low-temperature environments is low and the problem of reduced contrast is caused, or continuous for a long time. At the time of driving, problems such as development afterimages due to charge accumulation will become more prominent. Therefore, if it is only a technology proposed in the past, it will make it more difficult to solve both problems at the same time. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-287324 [Patent Document 2] Japanese Patent Application Laid-Open No. 10-104633

[Problems to be Solved by the Invention] The present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device which can quickly alleviate the accumulated charge and improve the transparency or solubility or alignment in view of these circumstances. for purpose. [Solution to the problem]

As a result of intensive studies, the present inventors have found that the use of a specific diamine is extremely effective in reducing the relaxation time of the accumulated charge, and thus completed the present invention.

The liquid crystal alignment agent of the present invention that can achieve the above object is characterized by comprising a polymer obtained from a diamine component containing a diamine having a structure represented by the following formula [1], and an organic solvent.

(In the formula [1], Y ¹ represents an S atom or an O atom, and * represents a bonding site with another group. In addition, an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group).

The polymer is formed from a polyimide precursor of a polycondensate of a polycondensation product of a diamine and a tetracarboxylic dianhydride having a structure represented by the aforementioned formula [1], and a polyimide of a polyimide Preferably, at least one polymer selected from the group is used.

Moreover, the said diamine has a special thing represented by following formula [2].

(In the formula [2], the definition of Y ¹ is the same as the above formula [1], R ² each independently represents a single bond or the structure of the following formula [3], n represents an integer of 1 to 3; Any hydrogen atom may be substituted by a monovalent organic group). (Formula [3], R ³ represents a single bond, -O -, - COO -, - OCO-, - (CH 2) l -, - O (CH 2) m O -, - CONH- and -NHCO -Selected divalent organic group (l, m represents integers from 1 to 5), * ₁ represents a site bonded to a benzene ring in formula [2], and * ₂ represents an amine group in formula [2] Bonding site).

The polymer is preferably at least one selected from the group consisting of a polyimide precursor comprising a structural unit represented by the following formula [4] and a polyimide comprising a fluorimide compound. (In the formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent group derived from a diamine having a structure represented by the formula [2] or the formula [3]. Organic groups: R ⁴ and R ⁵ represent 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, an alkyl group having 1 to 5 carbon atoms, and 2 to 5 carbon atoms (Alkenyl or alkynyl having 2 to 5 carbon atoms).

The liquid crystal alignment film of the present invention which can achieve the above object is characterized in that it can be prepared from the liquid crystal alignment agent.

The liquid crystal display element of the present invention that can achieve the above-mentioned object is characterized by including the liquid crystal alignment film. [Effect of the invention]

According to the description of the present invention, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element can be provided which can quickly alleviate the accumulated charge and improve the transparency or solubility or alignment. [Embodiment of Invention]

Hereinafter, the present invention will be described in more detail.

<Diamine> 之 The liquid crystal alignment agent of the present invention is a polymer containing a diamine component containing a diamine having a structure represented by the following formula [1], and an organic solvent; first, the nature of the diamine will be described. content.

(In the formula [1], Y ¹ represents an S atom or an O atom, and * represents a bonding site with another group. In addition, an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group).

In formula [1], the monovalent organic group is: a hydrocarbon group; a hydrocarbon group containing a hydroxyl group, a carboxyl group, a hydroxyl group, a thiol group, or a carboxyl group; an ether group, an ester bond, an amidine bond, and the like, a hydrocarbon group connected via a bonding group A hydrocarbon group containing a silicon atom; a halogenated hydrocarbon group; an amine group; an inert group protected by a urethane-based protecting group such as t-butoxycarbonyl; The hydrocarbon group may be any of a straight chain, a branched chain, and a cyclic chain, and may be a saturated hydrocarbon or an unsaturated hydrocarbon. In addition, a part of the hydrogen atom in the hydrocarbon group may be replaced by a carboxyl group, a hydroxyl group, a thiol group, a silicon atom, a halogen atom, or the like, and may also be bonded by ether bonding, ester bonding, amidine bonding, and the like. Base and link.

Further, the alkylene group having 1 to 3 carbon atoms may be any of a straight chain, a branched chain, and a cyclic chain. Specifically, it is methyl, ethyl, n-propyl, isopropyl, cyclopropyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, 1 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl Group, 1,2-dimethyl-cyclopropane, 2,3-dimethyl-cyclopropane, 1-ethyl-cyclopropane, 2-ethyl-cyclopropane, 1, 1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl 2-methyl-n-propyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropyl, 2-isopropyl-cyclopropyl, 1,2, 2-trimethyl-cyclopropane, 1,2,3-trimethyl-cyclopropane, 2,2,3-trimethyl-cyclopropane, 1-ethyl-2-methyl -Cyclopropane, 2-ethyl-1-methyl-cyclopropane, 2-ethyl-2-methyl-cyclopropane, and 2-ethyl-3-methyl-cyclopropane Wait.

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

In the structure of the above formula [1], from the viewpoint that the bonding position of the five-membered ring of the benzene ring is a moving charge, the carbon atom beside Y ¹ on the five-membered ring represented by the following formula [1-1] is Better.

The specific diamine can be represented, for example, by the following formula [1-2], and particularly preferably by the diamine represented by the following formula [1-3]. In addition, the diamine represented by the formula [1-4] Amines are preferred.

In formulas [1-2] to [1-4], the definition of Y ¹ is the same as that in the case of the aforementioned formula [1], and Q ¹ and Q ² are each independently a single bond or a divalent organic group. That is, Q ¹ and Q ² may have mutually different structures. The two Q ² in the formula [1-4] may have mutually different structures. In addition, when an arbitrary hydrogen atom on the benzene ring is the same as that in the above formula [1], it may be substituted with a monovalent organic group.

Preferred examples of the specific diamine include, for example, the diamine represented by the following formula [2], and more preferably the diamine represented by the formula [2-1].

In the above formulas [2] and [2-1], the definition of Y ¹ is the same as that of the aforementioned formula [1]. Two of R ² each independently represent a single bond or a structure of the following formula [3]. In addition, as in the case of the above formula [1], an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group.

In the formula (3), R ³ represents a single bond, -O-, -COO-, -OCO-,-(CH ₂ ) _l- , -O (CH ₂ ) _m O-, -CONH-, and -NHCO. -The divalent organic group selected by the formed group, wherein l and m represent integers of 1 to 5; and from the viewpoint of easing the charge accumulation, R ^{3 is} a single bond, -O-, -COO-,- OCO-, -CONH- or -NHCO- are preferred. In addition, * ₁ represents a bonding site with a benzene ring in Formula [2], and * ₂ represents a site bonded with an amine group in Formula [2]. N in the formula [2] and the formula [2-1] represents an integer of 1 to 3. It is preferably 1 or 2.

Specific examples of the diamine represented by the formula [2] include the diamine represented by the following formulas [4-1-1] to [4-1-12], but the invention is not limited to these. Among them, from the viewpoint of easing the accumulated charge and the alignment, [4-1-1], [4-1-2], [4-1-4] to [4-1-12] are preferable, and [4 -1-1], [4-1-2], [4-1-8] to [4-1-12] are particularly preferred.

<Synthesis method of diamine> (2) Next, the main synthesis method of the diamine of this invention is demonstrated. The method described below is a synthesis example, but it is not limited to this method.

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

The method for reducing the dinitro compound is not particularly limited. Generally, palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, and platinum sulfide are used as catalysts. Examples of the method for reduction in a solvent such as an ester, toluene, tetrahydrofuran, dioxane, or alcohol based on hydrogen, hydrazine, hydrogen chloride, or the like. If necessary, an autoclave can be used under pressure. On the other hand, in the case of a substituent structure that replaces a hydrogen atom of a benzene ring or a saturated hydrocarbon portion, an unsaturated bond site is included. When palladium carbon or platinum carbon is used, the unsaturated bond site is reduced, and There may be doubts about the formation of a saturated bond, so it is better to use reduced iron or transition metals such as tin and tin chloride as the catalyst for the reduction conditions.

The above reaction can be performed in the presence of a base. The base used is not particularly limited as long as it can be synthesized, and generally, for example, inorganic substances such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, sodium hydride, etc. Organic bases such as base, pyridine, dimethylaminopyridine, trimethylamine, triethylamine, tributylamine, and the like. In addition, depending on the situation, a palladium catalyst such as dibenzylideneacetone palladium or diphenylphosphinoferrocene palladium or a copper catalyst may be used in combination to increase the yield.

The diamine of the present invention obtained in this way can be used as a polyimide precursor such as polyamic acid or polyamic acid ester, polyimide, polyurea, polyamidine, etc. (these are collectively referred to as " Polymer "). This polymer can be used, for example, as a liquid crystal alignment agent dissolved in a specific organic solvent, but its use is not limited. Hereinafter, in this structure, the polymer containing the diamine represented by Formula [1] is demonstrated.

<Polymer> 聚合物 The polymer of the present invention is obtained by using the diamine of the present invention or a derivative thereof (as described later), and has a structure represented by the following formula [1] derived from a diamine component. .

(In the formula [1], Y ¹ represents an S atom or an O atom, and * represents a bonding site with another group. In addition, an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group).

The structures of these polymers derived from the diamine component represented by the above formula [1] are preferably those having the structure represented by the following formula [2-2].

(In the formula [2-2], the definition of Y ¹ is the same as the above formula [1], R ² each independently represents a single bond or the structure of the following formula [3], n represents an integer of 1 to 3, * ₂ represents a site bonded to another base. Any hydrogen atom of the benzene ring may be substituted by a monovalent organic group).

(Formula [3], R ³ represents a single bond, -O -, - COO -, - OCO-, - (CH 2) l -, - O (CH 2) m O -, - CONH-, and - NHCO- selected divalent organic group (l, m represents integers from 1 to 5), * ₁ represents a site bonded to a benzene ring in formula [2], and * ₂ represents a site bonded to another base ).

Among them, the above-mentioned diamine derivative of the present invention includes, for example, a structure obtained by linking two or more structures described above, or having the structure linked by -O-, -S-, -COO-, or -OCO- Structural diamines, etc. In addition, the structure derived from the diamine component may include a structure derived from another diamine in addition to the structure of the formula [2] (as described later).

The monovalent organic group or the alkylene group having 1 to 3 carbon atoms in the formula [2] has the same content as the formula [1], for example.

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

(In the formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent group derived from a diamine having a structure represented by the formula [2] or the formula [3]. Organic groups: R ⁴ and R ⁵ represent 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, an alkyl group having 1 to 5 carbon atoms, and 2 to 5 carbon atoms (Alkenyl or alkynyl having 2 to 5 carbon atoms).

In formula [4], an alkyl group having 1 to 5 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl Alkenyl, isopentyl, s-pentyl, t-pentyl, etc., alkenyl having 2 to 5 carbon atoms, for example, vinyl, allyl, 1-propenyl, 1-butenyl, 2-butyl Alkenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, etc., alkynyl groups having 2 to 5 carbon atoms, for example, ethynyl, 1 -Propynyl, 2-propynyl, 3-butynyl, pentynyl and the like. Among these, from the viewpoint that the fluorene imidization reaction is easy to occur during heating, R ¹ and R ² are preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. From the standpoint, A ¹ and A ² are preferably a hydrogen atom or a methyl group.

As long as X ^{1 is a} tetravalent organic group derived from a tetracarboxylic acid derivative, its structure is not particularly limited. In addition, X ¹ can meet the required characteristics to the extent that the polymer is soluble in a solvent or coated with a liquid crystal alignment agent, the liquid crystal alignment when used as a liquid crystal alignment film, a voltage holding ratio, and an accumulated charge. As appropriate, one or two or more kinds are mixed in the same polymer.

X ¹ , not only tetracarboxylic dianhydride, but also tetracarboxylic acid, tetracarboxylic dihalide compound, tetracarboxylic dialkyl ester compound, or tetracarboxylic dialkyl dihalide compound of the tetracarboxylic acid derivative . The tetracarboxylic dianhydride or its derivative is preferably at least one selected from the tetracarboxylic dianhydride or its derivative represented by the following formula [5].

In formula [5], V ¹ is a tetravalent organic group having an alicyclic structure, and the structure is not particularly limited. Specifically, for example, the following formulas [V ¹ -1] to [V ¹ -44].

In the formulas [V ¹ -1] to [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 olefin having 2 to 6 carbon atoms. The group, the alkynyl group having 2 to 6 carbon atoms, and the monovalent organic group or phenyl group having 1 to 6 carbon atoms containing a fluorine atom 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.

Specific structures of the formula [V ¹ -1] include, for example, structures represented by the following formulas [V ¹ -1-1] to [V ¹ -1-6]. From the viewpoints of liquid crystal alignment and photosensitivity, a structure represented by the following formula [V ¹ -1-1] is particularly preferable.

In the formula [4], as long as W ¹ is a divalent organic group having a diamine derived from the structure represented by the formula [1] or the formula [2], the structure is not particularly limited. Use more than 2 types. In addition, W ¹ may correspond to the structure of the diamine component used in the present invention, and may include a specific structure having a structure represented by Formula [1] (for example, the following formula [W ¹ -1] to Formula [W ^1- 12] A structure selected from the group consisting of the compounds represented by at least 1).

However, it is not necessary that all of W ¹ be a structure corresponding to the aforementioned diamine. A part of W ¹ may contain a structure corresponding to a diamine (other diamine) other than the above diamine. Structures corresponding to other diamines (hereinafter, also referred to as “structures W ² ”) can be generalized as shown in the following formula [6]. In addition, A ¹ and A ² in the following formula [6] have the same contents as those in the formula [4].

Examples of the structure W ² represented by the formula [6] are, for example, those represented by the following formulas [W ² -1] to [W ² -173].

The Boc groups in the formulas [W ² -168], [W ² -169], [W ² -172], and [W ² -173] may be tert-butoxycarbonyl groups as shown below. Means. Hereinafter, in the description, a tert-butoxycarbonyl group is also referred to as a Boc group.

When the polyimide precursor containing the structural unit represented by the formula [4] and the structural unit represented by the formula [6] is also contained, the structural unit represented by the formula [4] is relative to the formula [4] and The sum of the formula [6] is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more.

When the molecular weight of the polyimide precursor or polyimide of the polymer contained in the liquid crystal alignment agent of the present invention is used to prepare a liquid crystal alignment film from a liquid crystal alignment agent containing the polymer, the coating film (liquid crystal alignment) is considered. Film) strength, workability during coating film formation, and coating film uniformity. 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 is more preferable.

<Manufacturing method of polymer> (2) Next, the main manufacturing method of the polymer contained in the liquid crystal aligning agent of this invention is demonstrated. The method described below is a production example, but it is not limited to this method.

For example, in the case of a polymer containing a structural unit represented by the formula [4], which is a polyamic acid precursor of a polyimide precursor, the polymer can make tetracarboxylic dianhydride and Prepared by reacting amine components. As a method for producing polyamic acid through this reaction, a known synthesis method can be used. This synthesis method is a method in which a tetracarboxylic dianhydride and a diamine component are reacted in an organic solvent. This method is advantageous in that it is easier to perform in an organic solvent and does not generate by-products.

The organic solvent used in the above reaction is not particularly limited as long as it can dissolve the generated polyamidic acid (polymer). For example, N, N-dimethylformamide, N, N-dimethylformamide N-methylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfinium, tetramethylurea, pyridine, di Methyl fluorene, hexamethyl fluorene, γ-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentanone, methyl nonyl ketone, methyl ethyl ketone, methyl ethyl ketone Iso-isopentanone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolvate acetate, butylcarbitol , Ethylcarbitol, 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, diisobutyl ester, pentyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methyl cyclohexene, propyl ether, dihexyl ether, Dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, N-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3-methoxypropionic acid Ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, glyme, 4 -Hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropaneamide, 3-ethoxy-N, N-dimethylpropaneamide, 3-butane Oxy-N, N-dimethylpropaneamide and the like. These can be used alone or in combination. Moreover, even if it does not dissolve the solvent of a polyamic acid (polymer), as long as it does not precipitate the produced polyamic acid, it can mix with the said organic solvent and use. In particular, the moisture in the organic solvent is to prevent the polymerization reaction and cause hydrolysis of the generated polyamic acid. Therefore, it is preferable to use an organic solvent that is as dehydrated and dried as possible.

When the tetracarboxylic dianhydride and the diamine component are reacted in an organic solvent, for example, the tetracarboxylic dianhydride is dispersed or dissolved in a solution of an organic solvent in which the diamine component is dissolved or dispersed by stirring. A method of adding after an organic solvent, a method of adding a diamine component to an organic solvent in which a tetracarboxylic dianhydride is dispersed or dissolved, and a method of adding a tetracarboxylic dianhydride and a diamine component alternately. Either of these methods can be used. In addition, in the case where the tetracarboxylic dianhydride or diamine component is formed of a plurality of compounds, the reaction can be performed in a state of being mixed in advance, or the reactions can be performed in sequence, or even obtained by individual reactions. The low-molecular-weight body may be mixed to form a high-molecular-weight body.

At this time, the temperature of the polycondensation can be selected from any temperature between -20 ° C and 150 ° C, but is preferably in the range of -5 ° C to 100 ° C. In addition, although the polycondensation reaction can be performed at any concentration, if the concentration is too low, it will not be easy to obtain a polymer with a high molecular weight. When the concentration is too high, the viscosity of the reaction solution will be excessively increased, making it difficult to achieve uniformity Therefore, the total concentration in the reaction solution of the tetracarboxylic dianhydride and the diamine component is preferably 1% to 50% by mass, and more preferably 5% to 30% by mass. Alternatively, the reaction may be performed at a high concentration in the initial stage, and then an organic solvent may be added.

In the polymerization reaction of polyamic acid, the ratio of the total molar number of tetracarboxylic dianhydride to the total molar number of diamine component (total molar number of tetracarboxylic dianhydride / total molar amount of diamine component Number), preferably 0.8 to 1.2. This is the same as a normal polycondensation reaction, and the closer the molar ratio is to 1.0, the larger the molecular weight of the polyamidic acid produced.

In the case where the polymer containing the structural unit represented by the formula [4] is a polyamidate, it can be reacted by a tetracarboxylic acid diester dichloride and a diamine component, or a tetracarboxylic acid diester and a diamine component. It can be prepared by reacting in the presence of a suitable condensing agent or base. Or, it can be prepared by first synthesizing polyamidic acid in advance by using the above method, and then using a polymer reaction to esterify the carboxylic acid in the polyamidic acid.

Specifically, for example, the tetracarboxylic acid diester dichloride and diamine are subjected to a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to -20 ° C to 150 ° C in the presence of a base and an organic solvent. A reaction of 24 hours, preferably 1 hour to 4 hours, can synthesize polyamidate.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine, or the like can be used. From the viewpoint of stably proceeding the reaction, pyridine is preferred. The addition amount of the base is an amount that can be easily removed and a high-molecular-weight body can be easily produced, and is preferably 2 mol times to 4 mol times relative to the tetracarboxylic acid diester dichloride.

In the case where the tetracarboxylic acid diester and the diamine component are subjected to polycondensation in the presence of a condensing agent, the base may be triphenylphosphite, dicyclohexylcarbonyldiamidine, 1-ethyl-3- (3-Dimethylaminopropyl) carbodiimide hydrochloride, N, N'-carbonyldiimidazole, dimethoxy-1,3,5-tris Methylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethylurea tetrafluoroborate, O- (benzotriazol-1-yl ) -N, N, N ', N'-tetramethylurea hexafluorophosphate, (2,3-dihydro-2-thiooxy-3-benzoxazolyl) phosphonic acid diphenyl ester , 4- (4,6-dimethoxy-1,3,5-tri 2-yl) 4-methoxymorpholinium chloride n-water and the like.

In the method using the above-mentioned condensing agent, when Lewis acid is added as an additive, the reaction can be efficiently performed. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The addition amount of the Lewis acid is preferably 0.1 mol times to 1.0 mol times relative to the diamine or tetracarboxylic acid diester to be reacted.

The solvent used in the above reaction can be the same as the solvent used in the synthesis of the polyamic acid shown above. From the viewpoint of the solubility of the monomers and polymers, N-methyl-2- Pyrrolidone and γ-butyrolactone are preferred, and these may be used singly or in combination of two or more kinds. The concentration at the time of synthesis is not easy to cause polymer precipitation, and it is easy to produce high molecular weight. From the viewpoint of the reaction of tetracarboxylic acid derivatives such as tetracarboxylic acid diester dichloride or tetracarboxylic acid diester with diamine components, The total concentration in the solution is preferably 1% to 30% by mass, and more preferably 5% to 20% by mass. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamidate should be dehydrated as much as possible, and it is preferable to prevent the external gas from being mixed in a nitrogen atmosphere.

When the polymer containing a structural unit represented by the formula [4] is polyimide, a compound having a divalent group represented by the formula [1] or the formula [2] in the main chain can be used to make the polyamido acid Obtained by dehydration and closed-loop treatment. In the polyfluorene imine, the dehydration ring closure rate (fluorine imidization rate) of the amino acid group is not necessarily 100%, and it can be arbitrarily adjusted according to the use or purpose.

Examples of the method for polyimidizing polyimide include, for example, directly heating a solution of polyamic acid by heating the polyimide, or adding a catalyst to a solution of polyamidic acid. Amination and other methods.

The temperature at which the polyfluorenic acid is subjected to thermal hydration in a solution is 100 ° C to 400 ° C, preferably 120 ° C to 250 ° C, so as to simultaneously exclude water generated from the fluorination reaction from the reaction system. The way is better.

Polyimide catalyst 醯 imidization is to add alkaline catalyst and acid anhydride to polyamic acid solution, and stir at -20 ℃ ～ 250 ℃, preferably 0 ℃ ～ 180 ℃. Way to proceed. The amount of alkaline catalyst is 0.5 mol times to 30 mol times of the amino acid group, preferably 2 mol times to 20 mol times of the amino acid group, and the amount of the acid anhydride is 1 mol times to 50 of the amino acid group. Molar times, preferably 3 to 30 mole times. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine can be used to maintain proper basicity during the reaction, and it is more preferable. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. When acetic anhydride is used, purification is easily performed after completion of the reaction, and is preferred. The rate of catalyst imidization can be controlled by adjusting the amount of catalyst, the reaction temperature, and the reaction time.

In addition, as described above, the polyamidoimide can also be prepared by heating the polyamidate at a high temperature to promote the dealcoholization reaction and closing the ring.

In addition, the polyimide, polyimide, and polyimide produced from polyimide precursors such as polyimide and polyimide, or a polyimide reaction solution are recovered. In this case, the reaction solution may be poured into a lean solvent to precipitate it. Examples of the lean solvent used in the precipitation include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. After filtering and recovering the polyfluorene imide precursor or the polyfluorene imide precipitated by adding a poor solvent, it can be dried at normal temperature or under heating at normal pressure or reduced pressure. In addition, the polyimide precursor or polyimide that is precipitated and recovered can be dissolved in an organic solvent, and by repeating the operation of reprecipitation and recovery 2 to 10 times, impurities in the polymer can be reduced. The lean solvents at this time, for example, alcohols, ketones, hydrocarbons, and the like, when using more than three types of lean solvents selected from these, the purification efficiency can be further improved, which is better.

The polymer of the present invention obtained in this manner can be used as a liquid crystal alignment agent by dissolving it in a specific organic solvent. The liquid crystal alignment agent is used by a liquid crystal display device as a liquid crystal alignment film for controlling the alignment of liquid crystal molecules of a liquid crystal layer. Hereinafter, a liquid crystal alignment agent containing the polymer of the present invention will be described.

<Liquid crystal alignment agent> (1) The liquid crystal alignment agent of the present invention is a polymer containing a diamine component containing a diamine having a structure derived from the diamine component of the formula [1]. The liquid crystal alignment agent preferably contains a polymer having a structure represented by the formula [2] derived from the diamine component. In addition, the polymer is preferably at least one selected from a polyimide containing a polyimide precursor having a structural unit represented by the formula [4] and a polyimide compound thereof.

However, all of the polymers contained in the liquid crystal alignment agent of the present invention may be the polymers of the present invention. As long as the range of the effects described in the present invention can be achieved, the polymers of the present invention may also be included. Contains 2 or more polymers of different structures. Alternatively, the polymer of the present invention may contain other polymers, that is, polymers having no divalent group represented by the formula [1] or the formula [2]. Examples of other types of polymers include polyamic acid, polyimide, polyamic acid ester, polyester, polyamine, polyurea, polyorganosiloxane, cellulose derivative, and polycondensation. Aldehydes, polystyrene or derivatives thereof, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates, and the like.

When the liquid crystal alignment agent of the present invention contains other polymers, the proportion of the polymer of the present invention is preferably 5% by mass or more relative to the entire polymer component. For example, for example, 5% to 95% by mass. 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 generally used in the form of a coating liquid from the viewpoint that a uniform film can be formed by a user when manufacturing a liquid crystal alignment film. The liquid crystal alignment agent of the present invention is preferably a coating solution containing the aforementioned polymer component and an organic solvent in which the polymer component is dissolved. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the thickness of the coating film to be formed. From a viewpoint of forming a uniform and defect-free coating film, 1 mass% or more is preferable, and from a viewpoint of solution storage stability, 10 mass% or less is preferable. A particularly good polymer concentration is 2% to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it is an organic solvent capable of dissolving a polymer. Specific examples thereof include, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, Dimethyl sulfene, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentyl Ketones, etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are more preferably used. The organic solvents exemplified here may be used alone or in combination. Moreover, even if it is a solvent which does not dissolve a polymer, if it is the range which does not precipitate the produced | generated polymer, it can mix and use in an organic solvent.

In addition, as the organic solvent contained in the liquid crystal alignment agent, in addition to the above solvents, a mixed solvent obtained by combining with a solvent that can improve the coatability or the smoothness of the surface of the coating film when the liquid crystal alignment agent is applied is generally used. In the liquid crystal alignment agent, these mixed solvents are also suitable. Specific examples of the organic solvents that can be used in combination include, for example, the following examples, but they 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 Alcohol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1 -Methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1, 2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethyl-1,3-hexanediol, 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 ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1- Methylpentyl acetate, 2-ethylbutyl Acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethyl 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 monomethyl ether acetate Ester, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol Alcohol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol Alcohol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate Methyl 3-ethoxypropionate Ester, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate Solvents such as esters, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and the like.

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

In the formula [S-1] and the formula [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 methyl, ethyl, n-propyl, and isopropyl. 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 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

Among the organic solvents that can be 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 glycol monobutyl ether or dipropylene glycol dimethyl ether is preferred. The types and contents of these solvents can be appropriately selected according to the coating device, coating conditions, and coating environment of the liquid crystal alignment agent.

These solvents are preferably 20% to 99% by mass of the entire solvent contained in the liquid crystal alignment agent. Among them, 20% to 90% by mass is more preferable. It is more preferably 20% by mass to 70% by mass.

The liquid crystal alignment agent of the present invention may further contain components other than the polymer component and the organic solvent within a range that does not impair the effect of the present invention. These additional components can, for example, improve the adhesion between the liquid crystal alignment film and the substrate, improve the adhesion between the liquid crystal alignment film and the sealing material, and increase the strength of the liquid crystal alignment film. 2. Adjust the dielectric constant of the liquid crystal alignment film and adjust the dielectric or conductive substance used in the resistor. Specific examples of these additional components have been disclosed in various well-known literatures on liquid crystal alignment agents. For example, the components are disclosed in paragraphs [0105] to [0116] of International Publication No. 2015/060357.

<Liquid crystal alignment film> The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. For example, a method for manufacturing a liquid crystal alignment film from a liquid crystal alignment agent is described. For example, the liquid crystal alignment agent in the form of a coating liquid is coated on a substrate, and after drying and firing, the obtained film is subjected to a rubbing treatment method or a light alignment treatment method. Method of applying alignment treatment, etc.

The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency. In addition to a glass substrate and a silicon nitride substrate, an acrylic substrate or a polycarbonate substrate may be used. Plastic substrates, etc. In this case, if a substrate on which an ITO electrode capable of driving liquid crystal is formed is used, it is preferable from the viewpoint of simplifying the manufacturing process. In the case of a reflective liquid crystal display element, if only one substrate is used, an opaque material such as a silicon wafer may be used. In this case, an electrode that can reflect light such as aluminum may also be used.

The method for applying the liquid crystal alignment agent is not particularly limited. In industry, screen printing, lithography, flexo printing, and inkjet are generally used. Other coating methods, such as a wetting method, a roll coating method, a slit coating method, a spin coater method, and a spray method, can be used according to the purpose.

The firing after the liquid crystal alignment agent is coated on the substrate is performed at a temperature of 50 ° C to 300 ° C, preferably 80 ° C to 250 ° C, using a heating means such as a hot plate, a hot air circulation furnace, and an infrared furnace. A coating film (liquid crystal alignment film) is formed by evaporation. When the thickness of the coating film formed after firing is too thick, the viewpoint of power consumption of the liquid crystal display element is disadvantageous. When it is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferably 5 nm to 300 nm, more preferably 10 nm to 100 nm. When the liquid crystal is aligned horizontally or obliquely, the coating film after firing may be subjected to rubbing or polarized ultraviolet radiation.

After the liquid crystal alignment agent is coated on the substrate, the heating means, such as a heating plate, a thermal cycle type oven, and an IR (infrared) type oven, can be used to evaporate and fire the solvent. For the drying and firing steps after the liquid crystal alignment agent is applied, any temperature and time can be selected. Generally, from the viewpoint of sufficiently removing the contained solvent, for example, firing is performed at 50 ° C to 120 ° C for 1 minute to 10 minutes, and then, firing is performed at 150 ° C to 300 ° C for 5 minutes to 120 minutes. And other conditions.

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

<Liquid crystal display element> 之 The liquid crystal display element of the present invention is the one having the above-mentioned liquid crystal alignment film. After a substrate with a liquid crystal alignment film is prepared from the liquid crystal alignment agent, a liquid crystal cell is produced according to a known method, and the liquid crystal crystal is used Cell as the component. For example, it is provided with a liquid crystal alignment film formed by two substrates arranged in opposite directions, a liquid crystal layer disposed between the substrates, and a liquid crystal alignment agent of the present invention disposed between the substrate and the liquid crystal layer. Liquid crystal display element of a liquid crystal cell.

The substrate used for the liquid crystal display element of the present invention is not particularly limited as long as it is a substrate having high transparency, and is generally a substrate having a transparent electrode for driving liquid crystals formed on the substrate. Specific examples are the same as those of the substrate described in the liquid crystal alignment film.

The liquid crystal alignment film is formed by applying the liquid crystal alignment agent of the present invention on the substrate and firing the liquid crystal alignment film. 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, for example, nematic liquid crystals and smectic liquid crystals, etc. Among them, nematic liquid crystals are preferred, and positive type liquid crystals can be used. Either a liquid crystal material or a negative liquid crystal material. Specifically, for example, MLC-2003, MLC-6608, MLC-6609, MLC-3019, MLC-2041, MLC-7026-100, etc. manufactured by Mok Corporation can be used.

Specifically, a transparent glass substrate is prepared, and a common electrode is provided on one substrate and a segment electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes, and can be formed into a pattern that can achieve a desired image display. Next, an insulating film covering the common electrode and the segment electrode is provided on each substrate. The insulating film may be, for example, a film formed of SiO ₂ -TiO ₂ obtained by a sol-gel method. Next, a liquid crystal alignment film is formed on each substrate according to the aforementioned conditions.

Next, a UV curable sealing material is disposed at a specific place on the substrate on one side of the two substrates on which the liquid crystal alignment film is formed, and then the liquid crystal is disposed at a specific number of places on the surface of the liquid crystal alignment film. The alignment film is bonded to the substrate on the other side in an opposite manner. After the liquid crystal is diffused to the front of the liquid crystal alignment film in a pressing manner, the substrate is fully irradiated with ultraviolet rays, and the sealing material is hardened to obtain a liquid crystal cell.

Or, for example, in the step after forming a liquid crystal alignment film on a substrate, when a sealing material is disposed at a specific place on one side of the substrate, an opening can be filled with liquid crystal from the outside. A liquid crystal material is injected into a liquid crystal cell at an opening portion of the sealing material. Next, the opening portion is sealed with an adhesive to prepare a liquid crystal cell. The liquid crystal material can be injected using a vacuum injection method or a method using a capillary phenomenon in the atmosphere.

In any of the above methods, in order to ensure that the liquid crystal cell is filled with a liquid crystal material, columnar protrusions may be provided on one side of the substrate, or spacers may be scattered on the substrate on one side, or spacers may be mixed into the sealing material. , Or a combination of these means.

Next, set the polarizer. Specifically, it is preferable to attach a pair of polarizing plates to the surface opposite to the liquid crystal layer of two substrates.

The liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to those described above as long as the liquid crystal alignment agent of the present invention is used, and may be produced by other known methods. The steps for producing a liquid crystal display element from a liquid crystal alignment agent are also disclosed in, for example, paragraphs [0074] to [0081] of JP-A-2015-135393 and many other documents.

As described above, the liquid crystal display element obtained by using the liquid crystal alignment agent of the present invention is one having excellent reliability and is suitable for large-screen and high-definition liquid crystal televisions.

[Examples] (1) Hereinafter, specific examples of the present invention will be described. The present invention is not limited to these examples.简称 The abbreviations of the compounds used below, and the methods of characteristic evaluation are as follows.

<Organic solvents> 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-glycidoxypropyltriethoxy Silane

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

In a 2L (liter) four-neck flask, add 2,5-dibromothiophene (50g, 208mmol), 4-nitrophenylboronic acid (72.9g, 436mmol), sodium carbonate (110g, 1040mmol), dimethyl Formamidine (500 g), pure water (100 g). Subsequently, tetra-triphenylphosphine palladium (2.5 g) was added in a nitrogen atmosphere at room temperature, and the temperature was raised to 100 ° C, followed by stirring for 48 hours. After confirming the completion of the reaction by HPLC (high-speed liquid chromatography), the obtained solid was filtered under reduced pressure, and resuspended and washed with pure water (500 g). The precipitated crystals were filtered under reduced pressure, washed with acetonitrile (350 g) and resuspended at 80 ° C, and then dried to obtain powder crystals (1) (yield 42 g, yield 50%). The NMR measurement results are shown below. 1H-NMR (DMSO-d ₆ ): 8.32-8.28 (4H, m), 8.03-8.00 (4H, m), 7.94 (2H, s)

A mixture of compound (1) (20 g, 61.3 mmol), 5 mass% Pt / C (50% water-containing type), characteristic egret activated carbon (2.0 g), and dioxane (100 g) was subjected to hydrogen pressurization. Stir at 80 ° C for 24 hours. After the reaction was completed, the catalyst was filtered and then concentrated to dryness. The obtained solid was recrystallized using ethyl acetate (200 g) and toluene (200 g), and the precipitated crystals were filtered under reduced pressure, washed with methanol (50 g), and dried to obtain powder crystal DA-1 (yield 8 g, Yield 50%). The NMR measurement results are shown below. 1H-NMR (DMSO-d ₆ ): 7.34-7.27 (4H, m), 7.09 (2H, s), 7.09-6.55 (4H, m), 5.28 (4H, s) <diamine compound (DA-2) Synthesis

In a 3 L (liter) four-necked flask, zinc chloride (120.3 g, 882 mmol) was added, the temperature was raised to 100 ° C, and vacuum drying was performed using an oil pump for 1 hour. Subsequently, toluene (460 g), diethylamine (45.0 g, 615 mmol), t-butanol (46.4 g, 626 mmol), and 2-bromo-4-nitroacetophenone were sequentially added at room temperature under a nitrogen atmosphere. (100.0 g, 410 mmol), 4-nitroacetophenone (104.2 g, 631 mmol), and stirred at room temperature for 3 days. After confirming the completion of the reaction using HPLC (high-speed liquid chromatography), a 5% sulfuric acid aqueous solution (400 g) was added for neutralization, and the mixture was stirred at room temperature for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with toluene (200 g), pure water (300 g), and methanol (200 g), and then dried to obtain crude crystals. The obtained crude crystals were completely dissolved in tetrahydrofuran (1340 g) at 60 ° C, and then ethanol (1340g) was added, followed by stirring at 5 ° C for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with ethanol (200 g), and then dried to obtain powder crystals (1) (yield 63 g, yield 45%). The NMR measurement results are shown below. 1H-NMR (DMSO-d ₆ ): 8.40-8.36 (4H, m), 8.28-8.24 (4H, m), 3.53 (4H, s)

In a 2 L (liter) four-necked flask, compound (1) (50 g, 152 mmol) and acetic anhydride (1000 g) were added, and then sulfuric acid (10 g) and acetic anhydride (200 g) were added dropwise. After completion of the dropwise addition, the temperature was raised to 140 ° C, and the mixture was stirred for 3 hours. After confirming the completion of the reaction by HPLC (high-speed liquid chromatography), the reaction solution was added to cold water (5000 g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with acetonitrile (500 g) and resuspended at 80 ° C, and then dried to obtain powder crystals (2) (yield 42 g, yield 90%). The NMR measurement results are shown below. 1H-NMR (DMSO-d ₆ ): 8.34-8.31 (4H, m), 8.16-8.13 (4H, m), 7.56 (2H, s)

A mixture of compound (2) (40 g, 129 mmol), 5 mass% Pt / C (50% water-containing type), characteristic egret activated carbon (4.0 g), and tetrahydrofuran (400 g) was subjected to hydrogen pressurization at 60 ° C. Stir at 12 ° C for 12 hours. After the reaction was completed, the catalyst was filtered and then concentrated to dryness. The obtained solid was recrystallized using acetonitrile (400 g), and the precipitated crystals were filtered under reduced pressure, washed with methanol (50 g), and dried to obtain powder crystal DA-2 (yield 20 g, yield 77%). The NMR measurement results are shown below. 1H-NMR (DMSO-d ₆ ): 7.42-7.38 (4H, m), 6.61-6.56 (6H, m), 5.28 (2H, s)

[Synthesis Example 1] (1) Put a DA-1 (1.60 g, 6.0 mmol) and DA-4 (0.79 g, 4.0 mmol) in a 100 ml four-necked flask equipped with a stirring device and a nitrogen introduction tube, and then add NMP: GBL. 24.0 g of a mixed solvent with a ratio of 1: 1 was stirred in a nitrogen atmosphere to dissolve it. After the solution was stirred, CA-1 (0.87 g, 4.0 mmol), CA-2 (1.04 g, 5.3 mmol), and 8 g of a mixed solvent of NMP: GBL = 1: 1 were added, and then stirred at 50 ° C. After 12 hours, a polyamidic acid solution (PAA-A1) was prepared.

[Synthesis Examples 2 to 7] As shown in Table 1, a diamine component, a tetracarboxylic acid component, and a solvent were used, except for the reaction temperatures shown in Table 1. Polyamino acid solutions (PAA-A2) to (PAA-A4) and polyamino acid solutions (PAA-B1) to (PAA-B3) shown in Table 1 were obtained.

[Synthesis Example 8] In a 200-ml four-necked flask equipped with a stirring device and a nitrogen introduction tube, DA-6 (4.03 g, 16.5 mmol), DA-7 (3.59 g, 9.0 mmol), and DA-8 ( 2.51 g, 4.5 mmol), 74.0 g of NMP was added, and the mixture was continuously stirred under nitrogen to dissolve. CA-3 (4.37 g, 19.5 mmol) and 9.0 g of NMP were added to the solution while stirring, and the mixture was stirred at 40 ° C for 3 hours. Subsequently, CA-2 (1.71 g, 8.7 mmol) and 9.0 g of NMP were added at 25 ° C, and the mixture was stirred for another 12 hours to prepare a polyamic acid solution. The viscosity of the polyamic acid solution at a temperature of 25 ° C was 480 mPa · s. The molecular weight of this polyamidic acid was Mn = 10,660 and Mw = 20,512. 80.0 g of this polyphosphonic acid solution was collected, 20.0 g of NMP was added, 6.8 g of acetic anhydride and 1.8 g of pyridine were added, and the reaction was performed at 50 ° C. for 3 hours. This reaction solution was poured into 434.4 g of methanol under stirring, and the precipitated precipitate was filtered off. This precipitate was washed with methanol, and dried under reduced pressure at 60 ° C to obtain a polyimide powder. The polyimide has a hydrazone imidization rate of 75%. To 20.0 g of the obtained polyimide powder, 80.0 g of NMP was added, and the mixture was stirred at 70 ° C. for 20 hr to dissolve, thereby preparing a polyimide solution (SPI-B4).

[Examples 1 to 19] and [Comparative Examples 1 to 4] (1) The polyamidic acid solution obtained in Synthesis Examples 1 to 7 and the polyamidoimine solution obtained in Synthesis Example 8 were mixed into the prepared liquid crystal alignment agent. The solvents have the composition shown in Table 2-1 and Table 2-2, and the solvent and additives are added to the stirring, and then stirred at room temperature for 2 hours to prepare a liquid crystal alignment agent.

<Production of a liquid crystal display element using a rubbing method> Prepare a glass substrate with electrodes having a size of 30 mm x 35 mm and a thickness of 0.7 mm. An IZO electrode having a viscous pattern is formed on the substrate as a counter electrode constituting the first layer. The second layer on the counter electrode of the first layer is a SiN (silicon nitride) film formed by a CVD method. The SiN film of the second layer has a film thickness of 500 nm and has a function as an interlayer insulating film. On the SiN film of the second layer, a dentate pixel electrode formed by patterning is arranged as an IZO film of the third layer, and two pictures such as the first pixel and the second pixel are formed. Vegetarian. The size of each pixel is 10 mm in length and about 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 on the third layer is composed of electrode elements having a "ㄑ" shape formed by buckling the central portion of a plurality of rows, as shown in the figure (Figure 3) disclosed in JP-A-2014-77845.栉 Tooth shape. The width in the short-side direction of each electrode element is 3 μm, and the interval between the electrode elements is 6 μm. The pixel electrode forming each picture is composed of a plurality of electrode elements with a bent "列" shape in the central portion of the array. Therefore, the shape of each pixel is not a rectangular shape, but has the same content as the electrode element. The central part is the shape of the "ㄑ" which is a roughly thick word that is bent. Therefore, each pixel is divided into an upper part and a lower part by using the central buckling portion as a boundary, that is, the first region having the upper side and the second region having the lower side.

When the first region and the second region of each pixel are compared, it is known that the formation directions of the electrode elements constituting the pixel electrodes 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 at an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel is in the second region of the pixel. The electrode element of the electrode forms an angle (clockwise) of -10 °. In addition, between the first region and the second region of each pixel, there is a turning operation of the liquid crystal in the plane of the substrate by the application of a voltage between the pixel electrode and the counter electrode (in-plane, opening and closing). The directions of) are opposite to each other.

Secondly, after filtering the liquid crystal alignment agent with a 1.0 μm filter, the glass substrates having a column spacer with a height of 4 μm were formed by spin coating the opposite substrates of the above-mentioned substrates with electrodes and forming ITO films. Next, after drying on a hot plate at 80 ° C. for 5 minutes, firing was performed at 230 ° C. for 20 minutes, and a polyimide film having a thickness of 60 nm was prepared on each substrate. The polyimide film surface was subjected to rubbing treatment using pure cloth under the conditions of a roller diameter of 120 mm, roll revolutions of 500 rpm, a platform moving speed of 30 mm / sec, and a friction cloth pressing pressure of 0.3 mm. Ultrasonic irradiation for 1 minute, and drying at 80 ° C for 10 minutes.

The above two types of substrates with liquid crystal alignment films were used, and their respective rubbing directions were antiparallel. The remaining liquid crystal injection ports were sealed and the surroundings were sealed to obtain a cell gap of 3.8 μm. Empty unit cell. After the liquid crystal (Molker, MLC-3019) was vacuum-injected into the empty cell at normal temperature, the injection port was sealed to prepare a liquid crystal cell with anti-parallel alignment. The obtained liquid crystal cell is a liquid crystal display element constituting an FFS mode. Subsequently, the liquid crystal cell was heated at 120 ° C. for 1 hour and left for a while for evaluation.

<Evaluation of afterglow fade time> Evaluation of afterglow was performed using the following optical system and the like. That is, the prepared liquid crystal cell is set between two polarizing plates whose polarizing axes are arranged in a vertical cross manner, and the LED backlight is turned on in a state where no voltage is applied to adjust the arrangement angle of the liquid crystal cell. Adjust the brightness of the transmitted light to a minimum. Next, an AC voltage having a frequency of 30 Hz was applied between the liquid crystal cells, a V-T curve (voltage-transmittance curve) was measured, and an AC voltage at a relative transmittance of 23% was calculated as a driving voltage. The residual image was evaluated as follows: an AC voltage with a frequency of 30% and a relative transmittance of 30% was applied to drive the liquid crystal cell, and a DC voltage of 1V was applied for 30 minutes. Subsequently, the value of the applied DC voltage was set to 0V, and only the application of the DC voltage was stopped, and driving was continued for 15 minutes in this state.

The afterimage was evaluated as a time when the relative transmittance was reduced to 30% or less until 30 minutes had elapsed from the time when the DC voltage was applied. Within 5 minutes, the case where the relative transmittance drops below 30% is "○", and within 6 minutes to 30 minutes, the evaluation method marked with "△" is evaluated. If it takes more than 30 minutes for the relative transmittance to decrease to less than 30%, it is considered that the afterimage cannot be resolved, and the evaluation method marked "×" is used for evaluation. The afterimage evaluation performed according to the above method was performed under a temperature condition where the temperature of the liquid crystal cell was 23 ° C.

<Assessment of Liquid Crystal Alignment Stability> (1) An AC voltage of 30 Hz and a frequency of 10 VPP was applied to the obtained liquid crystal cell in a constant temperature environment of 60 ° C for 168 hours. Subsequently, a short circuit is formed between the pixel electrode and the counter electrode of the liquid crystal cell, and it is left at room temperature for one day. After placing, place the liquid crystal cell between two polarizing plates whose polarizing axes are arranged in a vertical cross manner. With no voltage applied, place the backlight on and adjust the arrangement angle of the liquid crystal cell to penetrate the light. The minimum brightness. Subsequently, from the darkest angle in the second region of the first pixel to the darkest angle in the first region, the rotation angle when the liquid crystal cell is rotated is calculated as the angle Δ. The second pixel has the same method, and the second region is compared with the first region to calculate the same angle Δ. Then, the average value of the angle Δ values of the first pixel and the second pixel is calculated and used as the angle Δ of the liquid crystal cell. The smaller the value of the angle Δ of the liquid crystal cell, the better the stability of the liquid crystal alignment.

<Evaluation of optical characteristics (transparency)> A quartz substrate having a size of 40 mm × 40 mm and a thickness of 1.0 mm was prepared. Next, the liquid crystal alignment agent was filtered using a 1.0 μm filter, and then spin-coated on the quartz substrate. Next, after drying on a hot plate at 80 ° C. for 2 minutes, firing was performed at 230 ° C. for 20 minutes, and a polyimide film having a film thickness of 100 nm was prepared on each substrate. The evaluation of transparency is performed by measuring the transmittance of a substrate prepared by the aforementioned method. Specifically, the transmittance was measured using a measuring device UV-3600 (manufactured by Shimadzu Corporation) at a temperature of 25 ° C. and a scanning wavelength of 300 nm to 800 nm. At this time, the reference (example) was performed using an uncoated quartz substrate. The evaluation is to calculate the average transmittance at a wavelength of 450 nm to 800 nm. The higher the transmittance, the better the transparency.

<Evaluation Results> (1) The liquid crystal display elements using the liquid crystal alignment agents of Examples 1 to 4, 19, and Comparative Examples 1 to 4, the evaluation of the afterglow fade time and the evaluation of liquid crystal alignment stability performed as described above, The results of the evaluation of transparency are shown in Table 3-1, Table 3-2, and Table 3-3.

From Table 3-1, it was confirmed that the liquid crystal display element using the liquid crystal alignment agent of Examples 1 to 4 can quickly alleviate the accumulated charge, and can improve the alignment and transparency.

From Table 3-1 and Table 3-3, it was confirmed that the liquid crystal display elements using the liquid crystal alignment agent of Examples 1 to 4 and 19 can quickly alleviate the accumulated charge, and can improve the alignment and transparency.

Claims (7)

A liquid crystal alignment agent, comprising: a polymer obtained from a diamine component containing a diamine having a structure represented by the following formula [1], and an organic solvent; (In the formula [1], Y ¹ represents an S atom or an O atom, and * represents a bonding site with another group; and an arbitrary hydrogen atom of a benzene ring may be substituted by a monovalent organic group). The liquid crystal alignment agent according to claim 1, wherein the polymer is a polyimide precursor comprising a polycondensate of a diamine and a tetracarboxylic dianhydride having a structure represented by the aforementioned formula [1], and A polymer of at least one selected from the group consisting of polyimides of imidates. The liquid crystal alignment agent according to claim 1, wherein the diamine is represented by the following formula [2]; (In the formula [2], the definition of Y ¹ is the same as the above formula [1], R ² each independently represents a single bond or the structure of the following formula [3], n represents an integer of 1 to 3; Any hydrogen atom can be replaced by a monovalent organic group) (Formula [3], R ³ represents a single bond, -O -, - COO -, - OCO-, - (CH 2) l -, - O (CH 2) m O -, - CONH- and -NHCO -Selected divalent organic group (l, m represents integers from 1 to 5), * ₁ represents a site bonded to a benzene ring in formula [2], and * ₂ represents an amine group in formula [2] Bonding site). The liquid crystal alignment agent according to claim 2, wherein the diamine is represented by the following formula [2]; (In the formula [2], the definition of Y ¹ is the same as the above formula [1], R ² each independently represents a single bond or the structure of the following formula [3], n represents an integer of 1 to 3; Any hydrogen atom can be replaced by a monovalent organic group) (Formula [3], R ³ represents a single bond, -O -, - COO -, - OCO-, - (CH 2) l -, - O (CH 2) m O -, - CONH- and -NHCO -Selected divalent organic group (l, m represents integers from 1 to 5), * ₁ represents a site bonded to a benzene ring in formula [2], and * ₂ represents an amine group in formula [2] Bonding site). The liquid crystal alignment agent according to any one of claims 1 to 4, wherein the polymer is a polymer of a polyimide precursor containing a structural unit represented by the following formula [4] and a polyimide compound thereof. At least one selected from iminium; (In the formula [4], X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and W ¹ is a divalent group derived from a diamine having a structure represented by the formula [2] or the formula [3]. Organic groups; R ⁴ and R ⁵ represent 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, an alkyl group having 1 to 5 carbon atoms, and 2 to 5 carbon atoms (Alkenyl or alkynyl having 2 to 5 carbon atoms). A liquid crystal alignment film, which is obtained by the liquid crystal alignment agent according to any one of claim 1 to claim 5. A liquid crystal display element characterized by having a liquid crystal alignment film of claim 6.