TW201726766A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal aligning agent which is especially suitable for PSA liquid crystal display elements having high response speed. A liquid crystal aligning agent which contains at least one polymer selected from the group consisting of polyamic acids obtained by reacting a diamine component containing a diamine compound having a bond dissociation energy barrier in triplet state of 30 kcal/mol or less as calculated with use of Gaussian09, preferably a diamine represented by one of formulae (2), and a tetracarboxylic acid dianhydride component and polyimide polymers obtained by imidizing the polyamic acids. (In the formulae, each of X1-X3 and X5 represents a single bond or the like; X4 represents an alkyl group having 1-18 carbon atoms, or the like; T represents an alkylene group having 1-6 carbon atoms; R1 represents an OH group or the like; each of R2-R5 represents a hydrogen atom; and Y represents a -CH2- group or the like).

Description

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

The present invention relates to a liquid crystal alignment element, a liquid crystal alignment film, and a liquid crystal display element, and is suitable for a liquid crystal display element of a vertical alignment type produced by irradiating ultraviolet rays with a voltage applied to liquid crystal molecules.

In a liquid crystal display device in which a liquid crystal molecule which is vertically aligned with respect to a substrate is responsive to an electric field (also referred to as a vertical alignment (VA) method), a manufacturing process includes a side in which a voltage is applied to the liquid crystal molecules while irradiating ultraviolet rays. The steps.

In the liquid crystal display device of the above-described vertical alignment type, it is known that a photopolymerizable compound is added to the liquid crystal composition, and a vertical alignment film such as a polyimide film is used, and a voltage is applied to the liquid crystal cell. A PSA (Polymer Sustained Alignment) element that irradiates ultraviolet rays to increase the response speed of liquid crystal (refer to Patent Document 1 and Non-Patent Document 1).

In the above PSA mode element, generally, the tilt direction of the liquid crystal molecules in response to the electric field is set by protrusions or devices provided on the substrate. It is controlled by a slit or the like placed on the display electrode. However, by adding a photopolymerizable compound to the liquid crystal composition and applying ultraviolet light to the liquid crystal cell, the liquid crystal molecules can be formed on the liquid crystal alignment film. Polymer structure in the oblique direction. Therefore, it is claimed that the response speed of the liquid crystal display element can be made faster than by controlling the tilt direction of the liquid crystal molecules only by protrusions or slits.

On the other hand, in the liquid crystal display device of the PSA type, there is a problem in that the solubility of the polymerizable compound added to the liquid crystal is low, and when the amount of addition is increased, precipitation occurs at a low temperature, but if the polymerizable compound is reduced, When the amount is added, a good alignment state cannot be obtained. Further, since the unreacted polymerizable compound remaining in the liquid crystal becomes an impurity (contamination) in the liquid crystal, there is a problem that the reliability of the liquid crystal display element is lowered. Further, when the amount of irradiation of the UV irradiation treatment required in the PSA method is large, the components in the liquid crystal are decomposed, which causes a decrease in reliability.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-307720

[Patent Document 2] International Publication WO2015/033921 (2015.3.12 publication) specification

[Non-patent literature]

[Non-Patent Document 1] K. Hanaoka, SID 04 DIGEST, P. 1200-1202

[Non-Patent Document 2] K. H Y. -J. Lee, SID 09 DIGEST, P. 666-668

In recent years, as the quality of liquid crystal display elements has improved, it has been expected that the response speed to liquid crystals with applied voltages is faster. Therefore, it is necessary to efficiently polymerize the polymerizable compound under irradiation with long-wavelength ultraviolet rays which are not accompanied by decomposition of components in the liquid crystal, and to exhibit an alignment fixing ability. Further, it is required that the unreacted polymerizable compound does not remain after the ultraviolet irradiation, and the reliability of the liquid crystal display element is not adversely affected.

An object of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal alignment film which can improve the response speed of a liquid crystal display element obtained by reacting a polymerizable compound in a liquid crystal and/or a liquid crystal alignment film without the problems of the above-described prior art. And liquid crystal display elements.

The inventors of the present invention have completed the present invention to achieve the above problems.

The present invention relates to a liquid crystal alignment agent comprising at least one polyimine-based polymer selected from the group consisting of polylysine and polyamidene obtained by imidating the polyamidinate ( Hereinafter, it is also referred to as "specific polymer", which is obtained by reacting a diamine component with a tetracarboxylic dianhydride component, and a diamine compound contained in the diamine component (hereinafter also referred to as "specific The diamine", preferably a diamine compound represented by any one of the following formulas, has a bond dissociation barrier of 30 kcal/mol in a triplet state calculated by Gaussian 09 The following key bindings.

In the formula (2), X ₁ represents a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O-, -COO-, and -OCO-. At least one selected from the group. X ₂ represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring, and when X ₂ is a cyclohexane ring, it is permeable to 4- The ketone (4-chromanone) skeleton is bonded to the screw to bond. X ₃ represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring. When X ₂ and X ₃ are a cyclic group, any hydrogen atom on the cyclic group may be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a fluorine having 1 to 3 carbon atoms. The alkyl group is substituted with a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom. X ₄ represents a group consisting of an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, and a fluorine-containing alkoxy group having 1 to 18 carbon atoms. At least one of the selected ones. X ₅ represents a bond group of a single bond, -O-, -CH ₂ -, or -COO-. The T system represents an alkylene group having 1 to 6 carbon atoms. R ₁ represents -OH, -Ph, -OPh, or an alkoxy group having 1 to 4 carbon atoms. R ₂ represents a hydrogen atom, -Ph, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. R ₃ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. R ₄ and R ₅ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The Y system represents -CH ₂ - or -O-. Further, in the above, the pH system means a phenyl group.

According to the present invention, it is possible to provide a liquid crystal alignment element (especially a PSA type liquid crystal display element) which is a vertical alignment type with a fast response speed as a suitable liquid crystal alignment agent. According to the liquid crystal alignment agent of the present invention, even when ultraviolet light of a long wavelength is irradiated, a liquid crystal display element having a sufficiently high response speed can be produced.

In particular, the specific diamine which forms a specific polymer contained in the liquid crystal alignment agent of the present invention, the diamine having an acetophenone structure in the specific diamine, particularly the diamine represented by the above formula (1), In the case of the "photoreactive structure which generates a radical" and the "vertical alignment structure", the amount of introduction of the side chain of the polymer contained in the liquid crystal alignment agent can be reduced, and the response speed can be further improved. The liquid crystal display element can also improve the aggregation of the polymer or the formation of the coating film during the formation of the liquid crystal alignment film.

[Best Mode for Carrying Out the Invention] <specific diamine>

The special polymer used in the liquid crystal alignment agent of the present invention The diamine is a bonded diamine compound having a bond dissociation barrier in a triplet state calculated by Gaussian 09 of 30 kcal/mol or less.

Here, Gaussian 09 is a Gaussian 09 software for molecular orbital calculation manufactured by Gaussian Co., Ltd. (Gaussian 09, Revision D. 01, M. J. Frisch, et al, Gaussian, Inc., Wallingford CT, 2013.). In the present invention, this is used to calculate, and the calculation method uses the density general function method (DFT). The general function is calculated using B3LYP and the basis function using 6-31G(d). The calculation of the structural optimization of the molecular structure of the object in the triplet state uses the keyword opt and the spin multiplicity uses 3. By calculating the optimized structure of the triplet state, the following calculation is performed: the optimization of the partial structure per 0.1 Å away from the distance between the atoms of the object from 1.4 Å to 2.9 Å (key The word opt=ModRedundant). The term "between atoms of an object" refers to an atom whose bond is dissociated by light irradiation. The potential energy curve obtained when the length of the extension is drawn is set, and the difference between the maximum value and the minimum value is set as "the bond disengagement barrier of the triplet state".

In the present invention, the term "acetophenone structure" means the following structure. In the formula, R represents a hydrogen atom or a monovalent organic group, n is an integer of 1 to 3, and R forms a condensed ring structure with an adjacent benzene ring. Further, α represents a carbon atom existing at the α position with respect to a carbonyl group. Further, in the present invention, "between atoms in the calculation of the bond dissociation barrier (ΔE)" means a carbonyl carbon atom in the acetophenone structure and an atom of a carbon atom having an α position.

The diamine compound is easily dissociated by the light irradiation and generates a radical, but it has been found by the inventors that the above-mentioned radical generation has a smaller bond dissociation barrier in the triplet state. That is, when the bond dissociation barrier calculated by Gaussian 09 is 30 kcal/mol or less (more preferably 25 kcal/mol or less, particularly preferably 20 kcal/mol or less), the diamine is used to obtain a specific polymer and further comprising A liquid crystal alignment agent of a specific polymer is used to obtain a liquid crystal display element, and the liquid crystal in the element is more likely to generate a tilt angle. Further, the lower limit of the bond dissociation barrier is preferably 5 kcal/mol or more from the viewpoint of stability of the compound.

Accordingly, according to the present invention, even when ultraviolet light of a long wavelength is irradiated, a liquid crystal display element having a sufficiently high response speed, in particular, a PSA type liquid crystal display element can be obtained.

As a specific diamine, which is preferably a diamine having an acetophenone structure, in the diamine having the above acetophenone structure, the bond between the carbonyl carbon and the α carbon thereof is in an excited triplet state by light irradiation. Dissociate.

As the diamine having an acetophenone structure, a diamine represented by any one of the following formulas is particularly preferred.

In the formula (2), X ₁ to X ₅ , T, R ₁ to R ₅ and Y are as defined above. Wherein X ₁ is preferably a single bond, -O- or -CH ₂ O-, and X ₂ is preferably a benzene ring, a cyclohexane ring or a cyclohexane ring which is bonded through a screw, X ₃ is preferably a single bond, a benzene ring or a cyclohexane ring, and X ₄ is preferably an alkyl group having 1 to 18 carbon atoms, and X ₅ is preferably a single bond or -O-. Further, R ₁ is preferably a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenyl group or a hydroxyl group, and R ₂ is a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, or Phenyl is preferred, and R ₃ is preferably a hydrogen atom, a methyl group, a methoxy group, an ethyl group, an ethoxy group or a phenyl group, and R ₄ and R ₅ are each a hydrogen atom, a methyl group or an ethyl group. A methoxy group, an ethoxy group, a phenyl group, or a hydroxyl group is preferred. Y is preferably -CH ₂ - or -O-.

Preferred examples of the diamine represented by the above formula are as follows.

In the above formulas 1 to 25, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each as defined above.

Among the diamines represented by the above formula, a diamine represented by the following formula (1) is preferred.

In the above formula (1), X ₁ to X ₄ are as defined above.

Among the diamines represented by the above formulas 1 to 25, the "bond dissociation barrier (?E) calculated by Gaussian 09 which the specific diamine has is as described in Table 1 below. Further, Me in Table 1 represents a methyl group.

<Vertically Aligned Side Chain Type Diamine>

In order to obtain the polyimine-based polymer polymer contained in the liquid crystal alignment agent of the present invention, the diamine component may contain other diamines other than the specific diamine. Examples of the other diamine include a diamine having a side chain in which liquid crystals are vertically aligned (also referred to as a vertical alignment side chain type diamine in the present invention).

Preferable examples of the above-mentioned vertical alignment side chain type diamine include a diamine having the following formula [II-1] or formula [II-2].

In the above formula [II-1], X ¹ represents a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O-, -COO- or OCO-. X ² represents a single bond or (CH ₂ ) _b - (b is an integer from 1 to 15). X ³ represents a single bond, -(CH ₂ ) _c - (c is an integer of 1 to 15), -O-, -CH ₂ O-, -COO- or OCO-. X ⁴ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a hetero ring, and any hydrogen atom of the cyclic group may be an alkyl group having 1 to 3 carbon atoms and a carbon number of 1 to 3 alkoxy group, fluorine-containing alkyl group having 1 to 3 carbon atoms, fluorine-containing alkoxy group having 1 to 3 carbon atoms or fluorine atom, and further, X ⁴ may be a carbon number 17 having a steroid skeleton. The divalent organic group selected from the organic group of 51. X ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring and a hetero ring, and any hydrogen atom on the ring group may be an alkyl group having 1 to 3 carbon atoms and a carbon number of 1 to The alkoxy group of 3, the fluorine-containing alkyl group having 1 to 3 carbon atoms, the fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom is substituted. The n system represents an integer from 0 to 4. X ⁶ is an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms.

[11]-X ⁷ -X ⁸ [II-2]

In the formula [II-2], X ⁷ represents a single bond, -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- or OCO-. X ⁸ represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms. Wherein, X ⁷ is preferably a single bond, -O-, -CH ₂ O-, -CONH-, -CON(CH ₃ )- or COO-, and is preferably a single bond, -O-, -CONH. - or COO-. Among them, X ⁸ is preferably an alkyl group having 8 to 18 carbon atoms.

The diamine represented by the following formula [II-1] is a diamine represented by the following formula [2-1].

X ¹ , X ² , X ³ , X ⁴ , X ⁵ and n in the above formula [2-1] are the same as those defined in the above formula [II-1], and m is an integer of 1 to 4 . Preferably, it is an integer of one.

Among them, from the viewpoint of availability of raw materials or ease of synthesis, X ¹ is a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O- Or COO- is preferred, and preferably a single bond, -(CH ₂ ) _a - (a is an integer from 1 to 10), -O-, -CH ₂ O- or COO-. Among them, X ² is preferably a single bond or (CH ₂ ) _b - (b is an integer of 1 to 10). Among them, in terms of easiness of synthesis, X ³ is preferably a single bond, -(CH ₂ ) _c - (c is an integer of 1 to 15), -O-, -CH ₂ O- or COO-. Further preferred is a single bond, -(CH ₂ ) _c - (c is an integer of 1 to 10), -O-, -CH ₂ O- or COO-.

Among them, from the viewpoint of easiness of synthesis, X ⁴ is preferably an organic group having a carbon number of 17 to 51 having a benzene ring, a cyclohexane ring or a steroid skeleton. Among them, X ⁵ is preferably a benzene ring or a cyclohexane ring. Among them, n is preferably 0 to 3, and more preferably 0 to 2, from the viewpoint of availability of raw materials or ease of synthesis.

Among them, X ⁶ is preferably an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms or a fluorine-containing alkoxy group having 1 to 10 carbon atoms. Further, it is preferably an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Particularly preferred are alkyl groups having 1 to 9 carbon atoms or alkoxy groups having 1 to 9 carbon atoms.

Preferred combinations of X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ and n in the formula [II-1] include those disclosed in International Publication WO2011/132751 (2011.10.27). (2-1) to (2-629), which are shown in Tables 6 to 47 of pages 13 to 34, are the same combination. Further, in the tables of the International Publications, X ¹ to X ⁶ in the present invention are represented as Y1 to Y6, and Y1 to Y6 are understood as X ¹ to X ⁶ .

Among them, (2-25)~(2-96), (2-145)~(2-168), (2-217)~(2-240), (2-268)~(2-315) A combination of (2-364)~(2-387), (2-436)~(2-483) or (2-603)~(2-615) is preferred. The most preferable combinations are (2-49)~(2-96), (2-145)~(2-168), (2-217)~(2-240), (2-603)~(2- 606), (2-607)~(2-609), (2-611), (2-612) or (2-624).

Specific examples of the vertical alignment side chain type diamine include the structures represented by the formula [2a-1] to the formula [2a-31] described in paragraphs 0044 to 0051 of Patent Document 2.

Among the above formulas [2a-1] to [2a-31], preferred are the formula [2a-1]~form [2a-6], the formula [2a-9]~the formula [2a-13] or the formula [ 2a-22]~[2a-31].

As a vertical alignment side chain type diamine having the formula [II-2] Examples of the compound include diamines represented by the following formulas [2b-1] to [2b-10].

(A ¹ represents an alkyl group having 1 to 22 carbon atoms or a fluorine-containing alkyl group).

In the above formula [2b-5]~form [2b-10], A ¹ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -CO- or NH - A ² represents a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched fluorine-containing alkyl group having 1 to 22 carbon atoms.

<Photoreactive side chain type diamine>

In order to obtain the polyimine-based polymer contained in the liquid crystal alignment agent of the present invention, the diamine component may further contain a photoreactive side chain represented by the following formula [3], in addition to the specific diamine. Diamine (also referred to as photoreactive side chain type diamine in the present invention).

In the formula [3], R ⁸ represents a single bond, -CH ₂ -, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N (CH ₃ )-, -CON(CH ₃ )-, or -N(CH ₃ )CO-. R ⁹ represents a single bond, or an alkylene group having 1 to 20 carbon atoms which is unsubstituted or substituted by a fluorine atom, and the -CH ₂ -alkyl group of the alkylene group may be optionally substituted by -CF ₂ - or -CH=CH- When any of the following groups are not adjacent to each other, they may be substituted by such groups: -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent Carbocyclic ring, divalent heterocyclic ring. R ¹⁰ represents a methacrylic group, an acrylic group, a vinyl group, an allyl group, a coumarin group, a styryl group or a cinnamyl group.

Among them, R ⁸ is preferably a single bond, -O-, -COO-, -NHCO, or -CONH-. The R ⁹ system can be formed by a usual organic synthesis. However, from the viewpoint of easiness of synthesis, a single bond or an alkylene group having 1 to 12 carbon atoms is preferred.

Further, a divalent carbocyclic ring or a heterocyclic ring in which any -CH ₂ - of R ⁹ is substituted may be specifically exemplified as follows.

From the viewpoint of photoreactivity, R ¹⁰ is preferably a methacrylic group, an acrylic group, or a vinyl group. The amount of the photoreactive side chain is preferably in a range in which a covalent bond is formed by irradiation with ultraviolet rays to increase the response speed of the liquid crystal, and in order to further improve the response speed of the liquid crystal, other characteristics are not obtained. Within the scope of the impact, as much as possible, the better.

The bonding position of the two amine groups (-NH ₂ ) in the formula (3) is not limited. Specifically, the bonding group of the side chain may be a 2, 3 position, a 2, 4 position, a 2, 5 position, a 2, 6 position, a 3, 4 position, or a 3, 5 position on the benzene ring. Among them, from the viewpoint of reactivity in synthesizing polyamic acid, the position of 2, 4, 2, 5 or 3, 5 is preferred. When it is easier to synthesize a diamine, it is preferable to use a 2, 4 position or a 3, 5 position.

Specific examples of the photoreactive side chain type diamine include the following.

(X ⁹ and X ¹⁰ each independently represent a single bond, -O-, -COO-, -NHCO-, or -NH- linkage group, and Y system represents a carbon number of 1 to 20 which can be substituted by a fluorine atom. alkyl).

Further, the photoreactive side chain type diamine may be a diamine represented by the following formula, which has a group which causes a photodimerization reaction in the side chain and a group which causes a photopolymerization reaction.

In the above formula, Y ₁ represents -CH ₂ -, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, or -CO-. Y ₂ represents an alkylene group having 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring, and one or more hydrogen atom groups of the alkylene group, the divalent carbocyclic ring or the heterocyclic ring may be a fluorine atom or Replaced by an organic base. When Y _{2 is} not adjacent to each other, -CH ₂ - may be substituted by such groups: -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, - NHCONH-, -CO-. Y ₃ represents -CH ₂ -, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, -CO-, or a single bond. Y ₄ represents cinnabarinyl. Y ₅ is a single bond, an alkylene group having 1 to 30 carbon atoms, a divalent carbocyclic ring or a heterocyclic ring, and one or more hydrogen atoms of the alkylene group, the divalent carbocyclic ring or the heterocyclic ring may be fluorine. Substituted by an atom or an organic group. When Y _{5 is} not adjacent to each other, -CH ₂ - may be substituted by such groups: -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, - NHCONH-, -CO-. Y ₆ represents a photopolymerizable group of an acryl group or a methacryl group.

The photoreactive side chain type diamine system can be used in one type or in a mixture of two or more types.

<Other diamines>

When the polyimine-based polymer contained in the liquid crystal alignment agent of the present invention is produced, a diamine other than the above-described diamine may be used in combination as the diamine component. Specifically, for example, those described in paragraph 0063 of Patent Document 2, such as p-phenylenediamine, 3,5-diaminobenzoic acid, and 2,5-diaminobenzoic acid, may be used alone or in combination of two or more. To use.

<Polyimide-based polymer>

The polyimine polymer contained in the liquid crystal alignment agent of the present invention is The polyamine component containing a specific diamine and a tetracarboxylic dianhydride component are (condensed) polymerized to produce polylysine, and the polyphosphonium amide is imidized to produce a polyimine.

As the diamine component, a vertical side chain type diamine, a photoreactive side chain type diamine, and/or the other diamine described above may be used in addition to the specific amine.

It is preferable to use 5 to 60 mol% of the specific diamine in the diamine component used for the production of the polyimine-based polymer, preferably 10 to 50 mol%, and particularly preferably 20 to 40 mol. ear%.

Further, when the diamine component used for the synthesis of the polyamic acid contains a vertical alignment side chain type diamine unit cell, it is preferably 5 to 50 mol%, more preferably 10% of the diamine component. 40% of the moles, especially good for 10~30%.

When a photoreactive side chain type diamine is used, it is preferable to use 5 to 50 mol%, preferably 10 to 40 mol%, of the diamine component used for the synthesis of the polyamidimide polymer. , especially good for 10~20 mol%.

The tetracarboxylic dianhydride component which reacts with the above diamine component is not particularly limited. Specifically, there are pyromellitic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic acid The dianhydride, the 2,3,5-tricarboxycyclopentyl acetic acid-1,4,2,3- dianhydride, and the like are described in the paragraph 0065 of the patent document 2, and may be used alone or in combination of two or more. Of course, the tetracarboxylic dianhydride may be used in combination of one type or two types or more depending on the characteristics of the liquid crystal alignment property, the voltage holding property, and the storage charge when the liquid crystal alignment film is formed.

<Manufacture of polyamic acid>

When a polyphthalic acid is obtained by a reaction of a diamine component and a tetracarboxylic dianhydride component, a well-known manufacturing method can be used. In general, there is a method of reacting a diamine component with a tetracarboxylic dianhydride component in an organic solvent. The reaction of the diamine component with the tetracarboxylic dianhydride is relatively easy to carry out in an organic solvent, and is advantageous in terms of not producing by-products.

The organic solvent used in the above reaction is not particularly limited as long as it is a polylysine which can be produced by dissolution. Further, even if the organic solvent which does not dissolve the polyamic acid is used in the range in which the produced polyamine does not precipitate, it may be used in combination with the above solvent. Further, since the water in the organic solvent hinders the polymerization reaction and further causes hydrolysis of the produced polylysine, it is preferred to use a dehydrated organic solvent.

The organic solvent used in the above reaction may, for example, be N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide or N-methyl. Those described in paragraph 0084 of Patent Document 2, such as carbamide and N-methyl-2-pyrrolidone. These organic solvents may be used singly or in combination.

A method of reacting a diamine component with a tetracarboxylic dianhydride component in an organic solvent may be any one of the following methods: stirring a solution obtained by dispersing or dissolving a diamine component in an organic solvent, and directly adding a tetracarboxylic acid II thereto A method of adding an anhydride component or dispersing or dissolving a tetracarboxylic dianhydride to an organic solvent, and then adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic dianhydride component in an organic solvent; Alternately added A method of a tetracarboxylic dianhydride component and a diamine component. Further, when the diamine component or the tetracarboxylic dianhydride component is composed of a plurality of compounds, it may be reacted in a state of being mixed beforehand, or may be sequentially reacted separately, or a low molecular weight body after each reaction may be further reacted. The reaction is mixed to form a high molecular weight body.

The temperature at which the diamine component and the tetracarboxylic dianhydride component are reacted is, for example, -20 ° C to 150 ° C, preferably -5 ° C to 100 ° C. In addition, the total concentration of the diamine component and the tetracarboxylic dianhydride component with respect to the reaction liquid is preferably from 1 to 50% by mass, and more preferably from 5 to 30% by mass.

In the above polymerization reaction, the ratio of the total number of moles of the tetracarboxylic dianhydride component in terms of the total number of moles of the diamine component can be selected depending on the molecular weight of the polyamic acid to be obtained. As with the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the produced polylysine, and the higher the range is 0.8 to 1.2.

The method for synthesizing polyamic acid used in the present invention is not limited to the above-described embodiment, and is the same as the general method for synthesizing poly-proline, and a tetracarboxylic acid or a tetracarboxylic acid dihalide halide having a corresponding structure is used. Instead of the above tetracarboxylic dianhydride, a tetracarboxylic acid derivative can be obtained by a known method to obtain a corresponding polylysine.

As a method of producing a polyimine by imidating the above-mentioned polyphosphonium amide, a hot hydrazine imidization of a solution in which polyamic acid is directly heated, and a touch in a solution of poly phthalic acid are mentioned. The catalyst of the medium is imidized. However, the rate of ruthenium imidization from polyaminic acid to polyimine is not necessarily 100%.

Temperature system for the thermal imidization of polylysine in solution From 100 ° C to 400 ° C, preferably from 120 ° C to 250 ° C, it is preferred to carry out the water formed by the ruthenium imidization reaction to the outside of the reaction system.

The catalytic oxime imidization of polylysine can be carried out by adding a basic catalyst and an acid anhydride to a solution of polyamic acid and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. . The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the prolyl group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to the prolyl group. 30 moles. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, the pyridine has a moderate alkalinity for the progress of the reaction. good. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. When acetic anhydride is used, it is preferred to carry out purification after completion of the reaction. The imidization ratio of the imidization by the catalyst oxime can be controlled by adjusting the amount of the catalyst, the reaction temperature, and the reaction time.

When the produced polylysine and/or polyimine are recovered from the reaction solution, the reaction solution can be poured into a poor solvent to precipitate. Examples of the poor solvent used in the precipitation include methanol, acetone, hexane, butyl cyanidin, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, water, and the like. The polymer which is poured into a poor solvent and precipitated can be dried by filtration at normal temperature or under normal pressure or under reduced pressure after filtration and recovery. Further, the recovered polymer is redissolved in an organic solvent and re-precipitated and recovered 2 to 10 times to reduce impurities in the polymer. Examples of the poor solvent in this case include alcohols, ketones, and hydrocarbons. When three or more kinds of poor solvents selected from the above are used, the efficiency of purification can be improved. Further improvement is therefore preferred.

<Liquid alignment agent>

The liquid crystal alignment agent of the present invention contains the above specific polymer, but the content of the specific polymer is preferably from 1 to 20% by mass, more preferably from 3 to 15% by mass, particularly preferably from 3 to 10% by mass. . The liquid crystal alignment agent of the present invention may contain other polymers in addition to the specific polymer. In this case, the content of the other polymer in the entire polymer component is preferably from 0.5 to 80% by mass, more preferably from 20 to 50% by mass.

The molecular weight of the polymer contained in the liquid crystal alignment agent is considered to be GPC (Gel) in consideration of the strength of the liquid crystal alignment film obtained by coating the liquid crystal alignment agent, the workability at the time of coating film formation, and the uniformity of the coating film. The weight average molecular weight measured by the Permeation Chromatography method is preferably 5,000 to 1,000,000, and more preferably 10,000 to 150,000.

The solvent to be contained in the liquid crystal alignment agent is not particularly limited as long as it is a solvent which can dissolve or disperse the component, and the component is a polymer having a structure represented by the above formula (1) in a side chain, and A polymerizable compound or the like which has a group which undergoes photopolymerization or photocrosslinking at each of two or more terminals, which are required to be contained, is required. For example, an organic solvent exemplified by the synthesis of the above polyamic acid can be mentioned. From the viewpoint of solubility, N-methyl-2-pyrrolidone, γ-butyrolactone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazoline A ketone, 3-methoxy-N,N-dimethylpropanamide is preferred. Of course, it is also possible to use two or more types of mixed solvents.

Also, a solvent mixture that enhances the uniformity or smoothness of the coating film It is preferred to use it in a solvent having a high solubility in a component containing a liquid crystal alignment agent. Examples of the solvent include isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, and butyl cellosolve acetate. It is described in paragraph 0094 of Patent Document 2. These solvents may also be mixed in various amounts. The solvent is preferably from 5 to 80% by mass based on the total amount of the solvent contained in the liquid crystal alignment agent, and more preferably from 20 to 60% by mass.

In the liquid crystal alignment agent of the present invention, a polymerizable compound having a group which undergoes photopolymerization or photocrosslinking at two or more terminals may be contained as required. When the polymerizable compound is contained, the content thereof is preferably 1 to 50 parts by mass, more preferably 5 to 30 parts by mass, per 100 parts by mass of the polymer.

The polymerizable compound is a compound having two or more terminal groups having a group for photopolymerization or photocrosslinking. Here, the "polymerizable compound having a group for photopolymerization" means a compound having a functional group which initiates polymerization by light irradiation. Moreover, the "compound having a group for photocrosslinking" means a compound having a functional group which is a polymer of a polymerizable compound or a precursor selected from a polyimine by irradiation with light. And reacting at least one polymer of the polyimine obtained by hydrazine imidization of the polyimine precursor and can be crosslinked with the same. Further, a compound having a group for performing photocrosslinking and a compound having a group for photocrosslinking also react with each other.

The liquid alignment agent of the present invention containing the above polymerizable compound is used in a vertical alignment mode of an SC-PVA liquid crystal display or the like In the liquid crystal display device, the response speed can be remarkably improved even in the case where the polymer having the side chain and the photoreactive side chain which vertically aligns the liquid crystal or the polymerizable compound is used alone. The addition amount of the polymerizable compound can also sufficiently increase the response speed.

Examples of the group to carry out photopolymerization or photocrosslinking include four kinds of monovalent groups represented by the following formula (IV).

(R ¹² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Z ¹ represents a divalent aromatic ring or a hetero group which may be substituted by an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. The ring Z ² represents a monovalent aromatic ring or a heterocyclic ring which may be substituted by an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.

Specific examples of the polymerizable compound include a compound having a group which undergoes photopolymerization at two terminals represented by the following formula (V), and a photopolymerization group represented by the following formula (VI). A compound having a terminal having a photocrosslinking group at the terminal end or a compound having a photocrosslinking group at each of two terminals represented by the following formula (VII).

Further, in the following formulae (V) to (VII), R ¹² , Z ¹ and Z ² are the same as defined in the above formula (IV), and R ¹ , Z ¹ and Z ² are the same, and Q ¹ is a divalent organic compound. base. Q ¹ is a ring structure having a stretching phenyl group (-C ₆ H ₄ -), a stretching biphenyl group (-C ₆ H ₄ -C ₆ H ₄ -), a cyclohexyl group (-C ₆ H ₁₀ -), or the like. It is better. This is because the interaction with the liquid crystal will be easily enhanced.

Specific examples of the polymerizable compound represented by the formula (V) include a polymerizable compound represented by the following formula (4). In the following formula (4), V and W are represented by a single bond or -R ¹ O-, and R ¹ is a linear or branched carbon alkyl group having 1 to 10 carbon atoms, preferably - R ¹ O- represents that R ¹ is a linear or branched carbon alkyl group having 2 to 6 carbon atoms. Further, V and W may be the same or may be different, and if they are the same, the synthesis is easy.

Further, as a group to carry out photopolymerization or photocrosslinking, even a polymerizable compound having an acrylate group or a methacrylate group instead of an α-methylene-γ-butyrolactone group, as long as it has a polymerizable compound having a structure in which an acrylate group or a methacrylate group is bonded to a phenyl group by a spacer such as an oxyalkylene group, and the above-mentioned α-methylene-γ-butyrolactone group at both terminals. Similarly, the polymerizable compound can also increase the response speed particularly greatly. Further, a polymerizable compound having a structure in which an acrylate group or a methacrylate group is bonded to a phenyl group by a spacer such as an oxyalkylene group is improved in heat stability and can sufficiently withstand high temperature ( For example, the firing temperature is 200 ° C or higher.

The liquid crystal alignment agent may contain components other than the above. As an example, a compound which improves film thickness uniformity or surface smoothness when a liquid crystal alignment agent is applied, a compound which improves the adhesion of a liquid crystal alignment film and a substrate, etc. are mentioned.

Examples of the compound which improves the uniformity of the film thickness or the surface smoothness include a fluorine-based surfactant, a polyfluorene-based surfactant, and a nonionic surfactant. More specifically, for example, F-Top EF301, EF303, EF352 (manufactured by Tuokai Mu Products Co., Ltd.), MEGAFACE F171, F173, R-30 (manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430, and FC431 (manufactured by Sumitomo 3M Co., Ltd.) ), AashiGuard AG710, Surflon S- 382, SC101, SC102, SC103, SC104, SC105, SC106 (made by Asahi Glass Co., Ltd.). The use ratio of the surfactant is preferably 0.01 to 2 parts by mass, and more preferably 0.01 to 1 part by mass, per 100 parts by mass of the total amount of the polymer contained in the liquid crystal alignment agent.

Specific examples of the compound which enhances the adhesion between the liquid crystal alignment film and the substrate include a compound containing a functional decane or a compound containing an epoxy group. For example, those described in paragraph 0096 of Patent Document 2, such as 3-aminopropyltrimethoxydecane and 3-aminopropyltriethoxydecane, may be mentioned.

Further, in order to further enhance the film strength of the liquid crystal alignment film, 2,2'-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane or tetrakis(methoxymethyl)bisphenol may be added. Phenolic compound. The amount of the compound is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the total amount of the polymer contained in the liquid crystal alignment agent.

Further, in addition to the above, the liquid crystal alignment agent may be added with a dielectric for changing the electrical properties such as the dielectric constant or the conductivity of the liquid crystal alignment film as long as it does not impair the effects of the present invention. Or conductive material.

By coating the liquid crystal alignment agent on a substrate and baking it, a liquid crystal alignment film which vertically aligns the liquid crystal can be formed. By using the liquid crystal alignment agent of the present invention, the photoreaction can be made highly sensitive even in the so-called PSA mode, and a sufficient tilt angle can be imparted even with a small amount of ultraviolet light irradiation.

For example, the liquid crystal alignment agent of the present invention can also be directly coated on After the substrate, a cured film obtained by drying and baking as required is used as a liquid crystal alignment film. Further, the cured film may be rubbed, irradiated with polarized light, light of a specific wavelength, or the like, or subjected to treatment with an ion beam or the like, or a state in which a voltage is applied to the liquid crystal display element after the liquid crystal is filled as an alignment film for PSA. Irradiation of UV. In particular, it can be used as an alignment film for PSA.

The substrate to be used at this time is not particularly limited as long as it is a substrate having high transparency, and a glass plate, polycarbonate, poly(meth)acrylate, polyether oxime, polyarylate, or polyurethane can be used. Ester, polyfluorene, polyether, polyether ketone, trimethyl decene, polyolefin, polyethylene terephthalate, (meth) acrylonitrile, triethylene sulfonyl cellulose, diethyl hydrazine cellulose A plastic substrate such as cellulose acetate butyrate. Further, from the viewpoint of simplification of the process, it is preferable to use a substrate on which an ITO electrode or the like for liquid crystal driving is formed. Further, in the reflective liquid crystal display device, an opaque material such as a germanium wafer may be used as the substrate on only one side, and a material that reflects light such as aluminum may be used as the electrode in this case.

The coating method of the liquid crystal alignment agent is not particularly limited, and examples thereof include a printing method such as screen printing, lithography, and flexographic printing, an inkjet method, a spray method, a roll coating method, or dipping, roll coating, and slit coating. Cloth, spin coating machine, etc. From the viewpoint of productivity, the transfer printing method can be widely used industrially, and is also suitable for use in the present invention.

The coating film formed by applying the liquid crystal alignment agent by the above method can be fired to form a cured film. The drying step after the application of the liquid crystal alignment agent is not necessarily required, but the time from the application to the completion of the firing is performed for each substrate. In the case where it is not necessarily or is not immediately fired after coating, it is preferred to carry out the drying step. In the drying, the solvent is removed until the shape of the coating film is not deformed by the conveyance of the substrate or the like, and the drying means is not particularly limited. For example, a method of drying at a temperature of 40 ° C to 150 ° C, preferably at 60 ° C to 100 ° C for 0.5 minutes to 30 minutes, preferably 1 minute to 5 minutes, is used.

The baking temperature of the coating film formed by applying the liquid crystal alignment agent is not limited, and is, for example, 100 to 350 ° C, preferably 120 to 300 ° C, more preferably 150 ° C to 250 ° C. The firing time is from 5 minutes to 240 minutes, preferably from 10 minutes to 90 minutes, and more preferably from 20 minutes to 90 minutes. The heating system can be carried out by a generally known method such as a hot plate, a hot air circulating furnace, an infrared furnace or the like.

Further, the thickness of the liquid crystal alignment film obtained by firing is not particularly limited, but is preferably 5 to 300 nm, and more preferably 10 to 100 nm.

<Liquid crystal display element>

In the liquid crystal display device of the present invention, a liquid crystal alignment film can be formed on a substrate by the above method, and a liquid crystal cell can be produced by a known method. Specific examples of the liquid crystal display device include a liquid crystal display device having a vertical alignment type of a liquid crystal cell, and having two substrates arranged in an opposing manner, a liquid crystal layer provided between the substrates, and a substrate and a liquid crystal. The above liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention between the layers. Specifically, it is a liquid crystal display element having a vertical alignment mode of a liquid crystal cell, which coats the liquid crystal alignment agent of the present invention on two substrates and fires them. Further, a liquid crystal alignment film is formed, and two liquid crystal layers are disposed opposite to each other by the liquid crystal alignment film, and a liquid crystal layer composed of liquid crystal is sandwiched between the two substrates, that is, a liquid crystal layer is provided in contact with the liquid crystal alignment film. It is produced by irradiating ultraviolet rays to the liquid crystal alignment film and the liquid crystal layer while applying a voltage.

The liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is irradiated with ultraviolet rays by applying a voltage to the liquid crystal alignment film and the liquid crystal layer to polymerize the polymerizable compound, and the photoreactive side of the polymer The chain or the side chain of the photoreactive property of the polymer reacts with the polymerizable compound, so that the alignment of the liquid crystal is more efficiently fixed, and a liquid crystal display element having a significantly higher response speed is formed.

The substrate to be used for the liquid crystal display device of the present invention is not particularly limited as long as it is a substrate having high transparency. However, a substrate on which a transparent electrode for driving liquid crystal is formed is usually formed on the substrate. As a specific example, the same as the substrate described in the above liquid crystal alignment film can be exemplified. In the liquid crystal display element of the present invention, since the liquid crystal alignment agent of the present invention is used, even a line of, for example, 1 to 10 μm is formed on one side substrate/ The slit electrode pattern can be operated without forming a slit pattern or a projection pattern on the counter substrate. With the liquid crystal display element of this configuration, the manufacturing process can be simplified to obtain high transmittance.

Further, in a high functional element such as a TFT type element, a member such as a transistor-like element formed between an electrode for liquid crystal driving and a substrate can be used.

In the case of a transmissive liquid crystal display element, generally used as described above For the reflective liquid crystal display element, an opaque substrate such as a germanium wafer may be used as the substrate on only one side. At this time, a material that reflects light, such as aluminum, may also be used for the electrode formed on the substrate.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display device of the present invention is not particularly limited, and a liquid crystal material used in a conventional vertical alignment method, for example, a negative liquid crystal such as MLC-6608 or MLC-6609 manufactured by Merck Co., Ltd. can be used. Further, in the PSA mode, for example, a liquid crystal containing a polymerizable compound as represented by the following formula can be used.

In the present invention, a well-known method can be exemplified as a method of sandwiching a liquid crystal layer between two substrates. For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and a spacer such as beads is spread on a liquid crystal alignment film of one of the substrates, and a surface on which one side of the liquid crystal alignment film is formed is located inside. The other method is to fit another substrate, and the liquid crystal is injected under reduced pressure and sealed. Further, a liquid crystal cell can be produced by the following method, and a pair of substrates on which a liquid crystal alignment film is formed can be prepared, and a liquid crystal alignment film is spread on a liquid crystal alignment film of one substrate, and then a liquid crystal is dropped thereon to form a liquid crystal. The other side of the substrate is bonded to the inner surface of the alignment film so as to be sealed. The thickness of the spacer is preferably from 1 to 30 μm, more preferably from 2 to 10 μm.

The step of producing a liquid crystal cell by applying a voltage to a liquid crystal alignment film and a liquid crystal layer while irradiating ultraviolet rays, for example, a method of applying a voltage between electrodes provided on a substrate to a liquid crystal alignment film An electric field is applied to the liquid crystal layer, and ultraviolet rays are irradiated while maintaining the electric field. Here, a voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The irradiation amount of the ultraviolet ray is, for example, 1 to 60 J/cm ² , preferably 40 J/cm ² or less, and when the amount of the ultraviolet ray irradiation is small, the reliability due to the destruction of the member constituting the liquid crystal display element can be suppressed, and the reduction can be reduced. The ultraviolet irradiation time is therefore suitable for improving the production efficiency.

When a voltage is applied to the liquid crystal alignment film and the liquid crystal layer, the polymerizable compound reacts to form a polymer, and the direction in which the liquid crystal molecules are tilted is memorized by the polymer, thereby accelerating the obtained voltage. The response speed of the liquid crystal display element. Further, when a voltage is applied to the liquid crystal alignment film and the liquid crystal layer, the ultraviolet ray is irradiated with a side chain having a liquid crystal alignment direction and a photoreactive side chain, and the polyfluorene precursor The polyimine obtained by imidization of the imine precursor oxime selects a photoreactive side chain between the at least one polymer, or a photoreactive side chain and a polymerizable compound possessed by the polymer. The reaction can accelerate the response speed of the obtained liquid crystal display element.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by the examples. The meanings, measurement methods, and the like in the following are as follows.

(acid dianhydride)

BODA: bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride

CBDA: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

PMDA: pyrethic acid dianhydride

(diamine)

p-PDA: p-phenylenediamine

DBA: 3,5-diaminobenzoic acid

3AMPDA: 3,5-diamino-N-(pyridin-3-ylmethyl)benzamide

<solvent>

NMP: N-methyl-2-pyrrolidone, DMF: N,N-dimethylformamide

BCS: butyl cellosolve, THF: tetrahydrofuran

<additive>

3AMP: 3-amine methylpyridine

<Method for determining molecular weight of polyimine]

Device: room temperature gel permeation chromatography (GPC): SSC-7200 by Senshu Scientific Co., Ltd.,

Column: Shodex pipe column (KD-803, KD-805)

Column temperature: 50 ° C

Dissolution: N,N'-dimethylformamide (as an additive: lithium bromide-hydrate (LiBr‧H ₂ O) is 30 mmol/L, phosphoric acid ‧ anhydrous crystal (o-phosphoric acid) is 30 mmol/L, tetrahydrofuran ( THF) is 10ml/L)

Flow rate: 1.0ml/min

Standard sample for the production of calibration lines: TSK standard polyethylene oxide (molecular weight of approximately 9,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weight of approximately 12,000, 4,000, 1,000) manufactured by Polymer Laboratories .

<Measurement of sulfhydrylation rate>

20 mg of polyimine powder was placed in an NMR sample tube (NMR sampling tube stand Φ5 manufactured by Kusano Scientific Co., Ltd.), and 1.0 ml of dimethyl hydrazine hydride (DMSO-d ₆ , 0.05% TMS mixture) was added and ultrasonication was applied thereto. It completely dissolves. The 500 MHz proton NMR of the solution was measured by a NMR measuring instrument (JNW-ECA500) manufactured by JEOL Ltd., Japan. The ruthenium imidization ratio was determined as follows: a proton derived from a structure having no change before and after imidization was used as a reference proton, and a peak cumulative value of the proton was used, and a proline derived from 9.5 to 10.0 ppm appeared. The cumulative value of the proton peak of the NH group is determined according to the following formula. In the following formula, x is the proton peak cumulative value of the NH group derived from proline, the peak cumulative value of the y-based reference proton, and the α-based polyproline (the imidization ratio is 0%) relative to 1 The ratio of the number of reference protons of protons of the NH group of proline.

醯 imidization rate (%) = (1-α‧x/y) × 100

<Key dissociation barrier of triplet state calculated by Gaussian09>

The carbonyl carbon of DA-1~DA-4 was calculated by Gaussian09 obtained from Gaussian 09, Revision D.01, MJ Frisch, GWTrucks, HB Schlegel, GEScuseria, Gaussian, Inc., Wallingford CT, 2013. The bond of the α carbon bond disengages the barrier under the triplet state, and the result is as follows.

DA-1: bond dissociation barrier is 23.7kcal/mol

DA-2: bond dissociation barrier is 34.9kcal/mol

DA-3: bond dissociation barrier is 81.0kcal/mol

DA-4: bond dissociation barrier is 7.4kcal/mol

[Synthesis of Diamine DA-1]

Synthesis of Compound 11

Compound 10 (50.00 g, 329 mmol), Compound 2 (82.35 g, 329 mmol), and DMF (250 g) were added to a nitrogen-substituted four-necked flask. Pyrrolidine (70.15 g, 986 mmol) was added while stirring at room temperature. Thereafter, the mixture was heated and stirred at 100 °C. The reaction was followed by HPLC (high performance liquid chromatography), and after completion of the reaction, the reaction solution was poured into pure water (1.5 L) and stirred. The precipitated solid was filtered, washed with pure water (1 L) and 2-propanol (500 g), and the solid was dried to obtain Compound 11 (yield: 63.8 g, yield: 50%).

¹ H NMR (DMSO-d ₆ , δ ppm): 9.32 (1H, brs), 7.04 (1H, d), 6.98 (1H, dd), 6.83 (1H, d), 2.62 (2H, s), 1.99 -1.96 (2H, m), 1.74-1.70 (4H, m), 1.48-0.805 (24H, m).

Synthesis of Compound 12

Compound 11 (20.00 g, 52.0 mmol), triethylamine (5.79 g, 57.2 mmol), and DMF (120 g) were added to a nitrogen-substituted four-necked flask, and stirred at room temperature. Thereafter, a solution of Compound 4 (10.16 g, 54.6 mmol) in DMF (40 g) was added dropwise. The reaction was followed by HPLC. After the reaction was completed, the reaction solution was poured into pure water (1 L), and the aqueous layer was removed by liquid separation, and then the organic layer was washed four times with pure water (500 mL), and the organic layer was dried over magnesium sulfate. Filtration was carried out and the filtrate was concentrated with an evaporator. The obtained crude oily product was heated and stirred with 2-propanol (100 g), and then cooled to room temperature, and the precipitated solid was filtered and dried to obtain compound 12 (amount of 13.7 g, Yield 48%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

Synthesis of diamine DA-1

Compound 12 (10.00 g, 30.8 mmol), 3 wt% Pt/C (aqueous) (2.00 g), and 1,4-dioxane (200 g) were added to a four-necked flask, followed by nitrogen substitution followed by hydrogen substitution. Stir at room temperature. The reaction was followed by HPLC, the catalyst was filtered after completion of the reaction, and the filtrate was concentrated with an evaporator to give a crude product. The obtained crude product was washed with methanol (400 g), and the solid was dried to obtain diamine DA-1 (yield: 8.01 g, yield: 90%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

[Synthesis of diamine DA-2]

Synthesis of Compound 9

Compound 8 (11.82 g, 57.2 mmol), Compound 3 (20.00 g, 52.0 mmol), and THF (160 g) were added to a nitrogen-substituted four-necked flask and stirred at 40 °C. Thereafter, an aqueous solution of sodium hydroxide (2.5 g) / pure water (80 g) was slowly added dropwise, and the reaction was carried out at room temperature after the completion of the dropwise addition. The reaction was followed by HPLC. After the reaction was completed, the reaction solution was poured into pure water (1 L) and filtered, and the obtained crude product was separately heated and pulverized with 2-propanol (300 g) and acetonitrile (350 g). The mixture was washed, and the solid was dried to give Compound 9 (yield: 24.6 g, yield: 84%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

Synthesis of diamine DA-2

Compound 9 (22.00 g, 39.0 mmol), 3 wt% Pt/C (aqueous) (6.6 g), and 1,4-dioxane (440 g) were added to a four-necked flask, followed by nitrogen substitution followed by hydrogen substitution. Stir at room temperature. The reaction was followed by HPLC, and after completion of the reaction, the catalyst was filtered and the filtrate was concentrated with an evaporator to give a crude product. The obtained crude product was heated and repulped with ethyl acetate (100 g), and the solid obtained by filtration was dried to obtain diamine DA-2 (amount of 11.9 g, yield) 61%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

[Synthesis of diamine DA-3]

Synthesis of Compound 7

Compound 3 (15.00 g, 39.0 mmol), triethylamine (4.74 g, 46.8 mmol), and THF (100 g) were added to a nitrogen-substituted four-necked flask, and the reaction solution was cooled to 10 ° C and stirred. Thereafter, a solution of Compound 6 (9.44 g, 41.0 mmol) in THF (40 g) was added dropwise. The reaction was followed by HPLC. After the reaction was completed, the reaction solution was poured into pure water (0.5 L), stirred at room temperature for a while and the precipitated solid was filtered, and sequentially purified water and 2-propane. After washing with an alcohol, the solid was dried to obtain a compound 7 (amount of 21.1 g, yield 94%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

Synthesis of diamine DA-3

Compound 7 (18.00 g, 31.1 mmol), 3 wt% Pt/C (aqueous) (7.2 g), and 1,4-dioxane (360 g) were added to a four-necked flask to carry out nitrogen substitution followed by hydrogen substitution. Stir at room temperature. The reaction was followed by HPLC, and after completion of the reaction, the catalyst was filtered and the filtrate was concentrated with an evaporator to give a crude product. The obtained crude product was washed with hexane (150 g), and the solid was dried to obtain diamine DA-3 (yield: 14.9 g, yield: 92%).

¹ H NMR (CDCl ₃ , δ ppm): 8.85 (1H, d), 8.33 (1H, dd), 7.60 (1H, dd), 7.78 (1H, dd), 7.10 (1H, d), 7.05 (1H, d ), 2.69 (2H, s), 2.16 (2H, d), 1.77 (4H, t), 1.62-1.58 (3H, m), 1.47-0.85 (21H, m).

(Manufacturing Example 1)

BODA (1.20 g, 4.8 mmol), DA-1 (2.36 g, 4.8 mmol), p-PDA (0.39 g, 3.6 mmol), and 3AMPDA (0.87 g, 3.6 mmol) were dissolved in NMP (18.4 g). After reacting at 60 ° C for 5 hours, CBDA (1.32 g, 7.1 mmol) and NMP (6.1 g) were added, and the mixture was reacted at 40 ° C for 10 hours to obtain a polyaminic acid solution.

After adding NMP to the polyamic acid solution (27 g) and diluting it to 6.5% by mass, acetic anhydride (4.7 g) and pyridine (1.5 g) were added as a ruthenium hydride catalyst, and the mixture was made at 70 ° C. Reaction for 3 hours. The reaction solution was poured into methanol (400 ml), and the obtained precipitate was collected by filtration. The precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyimine powder (A). The polyimine had a hydrazine imidation ratio of 72%, a number average molecular weight of 12,000, and a weight average molecular weight of 53,000.

NMP (22.0 g) was added to the obtained polyimine powder (A) (3.0 g), and the mixture was stirred at 70 ° C for 20 hours to be dissolved. To the solution, 3.0 g of 3AMP (1 wt% NMP solution), NMP (2.0 g), and BCS (20.0 g) were added, and the liquid crystal alignment agent (A1) was obtained by stirring at room temperature for 5 hours.

(Manufacturing Example 2)

BODA (1.60, 6.4 mmol), DA-2 (3.23 g, 6.4 mmol), 3AMPDA (1.16 g, 4.8 mmol), and p-PDA (0.52 g, 4.8 mmol) were dissolved in NMP (25.0 g), and After reacting at 60 ° C for 5 hours, CBDA (1.85 g, 9.4 mmol) and NMP (8.3 g) were added, and the mixture was reacted at 40 ° C for 10 hours to obtain a polyaminic acid solution.

After adding NMP to the polyamic acid solution (38 g) and diluting it to 6.5% by mass, acetic anhydride (6.6 g) and pyridine (2.0 g) were added as a ruthenium amide catalyst, and the reaction was carried out at 70 ° C. 3 hours. The reaction solution was poured into methanol (500 ml), and the obtained precipitate was collected by filtration. The precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyimine powder (B). The polyamidimide had a ruthenium iodide ratio of 73%, a number average molecular weight of 14,000, and a weight average molecular weight of 44,000.

NMP (44.0 g) was added to the obtained polyimine powder (B) (6.0 g), and the mixture was stirred at 70 ° C for 20 hours to be dissolved. To the solution, 6.0 g of 3AMP (1 wt% NMP solution), NMP (4.0 g), and BCS (40.0 g) were added, and the liquid crystal alignment agent (B1) was obtained by stirring at room temperature for 5 hours.

(Manufacturing Example 3)

BODA (5.00 g, 20.0 mmol), DBA (6.09 g, 40.0 mmol), 3AMPDA (7.27 g, 30.0 mmol), and DA-4 (11.42 g, 30.0 mmol) were dissolved in NMP (136.5 g) to 60 After reacting for 3 hours at ° C, PMDA (4.36 g, 48.5 mmol) and CBDA (11.37 g, 58.0 mmol) and NMP (45.51 g) were added, and reacted at 40 ° C for 10 hours to obtain a polyamidonic acid solution. .

After adding NMP to the polyamic acid solution (180 g) and diluting it to 6.5% by mass, acetic anhydride (40.0 g) and pyridine (12.4 g) were added as a ruthenium catalyst, and the reaction was carried out at 50 ° C. hour. The reaction solution was poured into methanol (2300 ml), and the obtained precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C to obtain a polyimine powder. End (C). The polyimine had a hydrazine imidation ratio of 78%, a number average molecular weight of 9000, and a weight average molecular weight of 20,000.

To the obtained polyimine powder (C) (6.0 g), NMP (44.0 g) was added, and the mixture was stirred at 70 ° C for 20 hours to dissolve. To the solution, 6.0 g of 3AMP (1 mass% NMP solution), NMP (4.0 g), and BCS (40.0 g) were added, and the liquid crystal alignment agent (C1) was obtained by stirring at room temperature for 5 hours.

5.0 g of the liquid crystal alignment agent (A1) obtained in the above-mentioned Example 1 as the first component, and 5.0 g of the liquid crystal alignment agent (C1) obtained as the second component were mixed and stirred by stirring for 1 hour. Liquid crystal alignment agent (A2).

(Manufacturing Example 4)

BODA (10.01 g, 40.0 mmol), 3AMPDA (4.85 g, 20.0 mmol), DA-4 (13.78 g, 40.0 mmol), and DA-5 (15.22 g, 40.0 mmol) were dissolved in NMP (166.2 g). After reacting at 60 ° C for 5 hours, CBDA (11.57 g, 59.0 mmol) and NMP (55.42 g) were added, and the reaction was carried out at 40 ° C for 10 hours to obtain a polyaminic acid solution.

After adding NMP to the polyamic acid solution (250 g) and diluting it to 6.5% by mass, acetic anhydride (45.49 g) and pyridine (14.3 g) were added as a ruthenium amide catalyst, and the reaction was carried out at 70 ° C. 3 hours. The reaction solution was poured into methanol (3300 ml) and the obtained precipitate was collected by filtration. The precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyimine powder (C). The polyamidimide has a ruthenium imidation ratio of 72% and a number average molecular weight. It was 21,000 and had a weight average molecular weight of 82,000.

NMP (44.0 g) was added to the obtained polyimine powder (C) (6.0 g), and the mixture was stirred at 70 ° C for 20 hours to be dissolved. To the solution, 6.0 g of 3AMP (1 mass% NMP solution), NMP (4.0 g), and BCS (40.0 g) were added, and the liquid crystal alignment agent (E1) was obtained by stirring at room temperature for 5 hours.

(Manufacturing Example 5)

BODA (4.00, 16.0 mmol), DA-5 (6.09 g, 16.0 mmol), 3AMPDA (2.91 g, 12.0 mmol), and p-PDA (1.30 g, 12.0 mmol) were dissolved in NMP (56.5 g) to After reacting at 60 ° C for 5 hours, CBDA (4.59 g, 23.4 mmol) and NMP (18.9 g) were added, and the mixture was reacted at 40 ° C for 10 hours to obtain a polyamidonic acid solution.

After adding NMP to the polyamic acid solution (85 g) and diluting it to 6.5% by mass, acetic anhydride (16.0 g) and pyridine (5.0 g) were added as a ruthenium amide catalyst, and the reaction was carried out at 70 ° C. 3 hours. The reaction solution was poured into methanol (1100 ml), and the obtained precipitate was collected by filtration. The precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyimine powder (D). The polyamidimide had a ruthenium iodide ratio of 73%, a number average molecular weight of 13,000, and a weight average molecular weight of 39,000.

NMP (44.0 g) was added to the obtained polyimine powder (D) (6.0 g), and the mixture was stirred at 50 ° C for 5 hours to be dissolved. To the solution, 6.0 g of 3AMP (1 wt% NMP solution), NMP (4.0 g), and BCS (40.0 g) were added, and the liquid crystal alignment agent (D1) was obtained by stirring at room temperature for 5 hours.

(Manufacturing Example 6)

5.0 g of the liquid crystal alignment agent (D1) obtained in Comparative Example 1 of the first component, and 5.0 g of the liquid crystal alignment agent (C1) obtained as Production Example 3 of the second component were mixed, and stirred by stirring for 1 hour. Liquid crystal alignment agent (D2).

(Manufacturing Example 7)

BODA (1.20 g, 4.8 mmol), DA-3 (2.49 g, 4.8 mmol), p-PDA (0.39 g, 3.6 mmol), and 3AMPDA (0.87 g, 3.6 mmol) were dissolved in NMP (18.9 g). After reacting at 60 ° C for 5 hours, CBDA (1.39 g, 7.1 mmol) and NMP (6.3 g) were added, and the mixture was reacted at 40 ° C for 10 hours to obtain a polyaminic acid solution.

After adding NMP to the polyamic acid solution (28 g) and diluting it to 6.5% by mass, acetic anhydride (4.8 g) and pyridine (1.5 g) were added as a ruthenium amide catalyst, and the reaction was carried out at 70 ° C. 3 hours. The reaction solution was poured into methanol (400 ml) and the obtained precipitate was filtered. The precipitate was washed with methanol, and dried under reduced pressure at 100 ° C to obtain a polyimine powder (F). The polyimine had a hydrazine imidation ratio of 70%, a number average molecular weight of 14,000, and a weight average molecular weight of 41,000.

NMP (22.0 g) was added to the obtained polyimine powder (A) (3.0 g), and the mixture was stirred at 70 ° C for 20 hours to be dissolved. To the solution, 3.0 g of 3AMP (1 wt% NMP solution), NMP (2.0 g), and BCS (20.0 g) were added, and a liquid crystal alignment agent (F1) was obtained by stirring at room temperature for 5 hours.

Regarding the above-mentioned liquid crystal alignment agents A1, B1, C1 The specifications of D1, E1, and F1 are shown in Table 2.

(Example 1: Production of liquid crystal cell)

Using the liquid crystal alignment agent (A1) obtained in Synthesis Example 1, the liquid crystal cell was produced in the same manner as described below. The liquid crystal alignment agent (A1) obtained in Example 1 was spin-coated on the ITO surface of an ITO electrode substrate on which an ITO electrode pattern having a pixel size of 100 μm × 300 μm and a line width/pitch of 5 μm was formed, and The hot plate at 80 ° C was dried for 90 seconds, and then fired in a hot air circulating oven at 200 ° C for 30 minutes to form a liquid crystal alignment film having a film thickness of 100 nm.

Further, the liquid crystal alignment agent (A1) was spin-coated on the ITO surface on which the electrode pattern was not formed, and dried on a hot plate at 80 ° C for 90 seconds, and then fired in a hot air circulating oven at 200 ° C for 30 minutes. Thus, a liquid crystal alignment film having a film thickness of 100 nm was formed.

On the liquid crystal alignment film of one of the above-mentioned substrates, a bead spacer having a diameter of 4 μm (manufactured by Nikko Kasei Co., Ltd., silk ball, SW-D1 4 μm) was spread on the substrate, and then a sealant was printed thereon (solvent type). Thermosetting epoxy resin). Next, another substrate is formed with a liquid The surface on one side of the crystal alignment film is placed on the inner side, and after bonding to the previous substrate, the sealant is cured to form an empty cell. A negative liquid crystal MLC-3023 (trade name, manufactured by Merck Co., Ltd.) containing a polymerizable compound for PSA was injected into the empty cell by a vacuum injection method to prepare a liquid crystal cell.

The response speed of the obtained liquid crystal cell was measured by the following method. Thereafter, in a state where a DC voltage of 15 V was applied to the liquid crystal cell, UV of a 365 nm band pass filter was irradiated from the outside of the liquid crystal cell at 10 J/cm ² . Thereafter, the response speed was measured again and compared to the response speed before and after the UV irradiation. Further, the pretilt angle of the pixel portion was measured for the unit cell after the UV irradiation. The results are shown in Table 2.

"Method for measuring response speed"

A measuring device composed of a backlight, a polarizing plate and a light amount detector which are arranged in a state of crossed Nicols, and a liquid crystal cell are disposed between a group of polarizing plates. The pattern of the ITO electrodes forming the line width/pitch at this time is at an angle of 45° with respect to the crossed Nicols. Then, a rectangular wave having a voltage of ±7 V and a frequency of 1 kHz is applied to the liquid crystal cell, and the change in the luminance observed by the light amount detector is saturated by the oscilloscope, and the luminance when the voltage is not applied is set to 0%. The time when the voltage of ±7 V is applied and the saturation is saturated is set to 100%, and the time taken for the luminance to change from 10% to 90% is taken as the response speed.

"Measurement of pretilt angle"

LCD Analyzer LCA-LUV42A manufactured by Mingling Technica was used. (Examples 2 to 3, Comparative Examples 1 to 4)

In Example 1, as shown in Table 2, except that the liquid crystal alignment agent (A2), (B2), (E1), (B1), (D1), or (D2) was used instead of the liquid crystal alignment agent (A1). The same operation as in Example 1 was carried out, and the response speed and the pretilt angle before and after the UV irradiation were measured. The results are summarized and shown in Table 3.

As can be seen from Table 2, in Examples 1 to 3, even when irradiated with a long wavelength of 365 nm, a tilt angle of 85 to 89.5° which is required for the PSA method or the VA method can be exhibited.

On the other hand, the inclination angles of Comparative Examples 1 to 4 were more than 89.5, and a sufficient inclination angle could not be exhibited.

This is considered to be because the polymerizable compound used in PSA does not absorb ultraviolet rays having a wavelength of 365 nm at all, and thus the liquid crystal alignment film system which does not have a portion for promoting photoreaction cannot sufficiently carry out the polymerization reaction.

[Industry Utilization]

The liquid crystal alignment agent of the present invention is useful not only as a liquid crystal alignment agent for producing a liquid crystal display element of a vertical alignment type such as a PSA liquid crystal display or an SC-PVA liquid crystal display, but also suitable for use in rubbing treatment or photoalignment. The use of the produced liquid crystal alignment film.

The entire contents of the specification, the patent application, the drawings, and the abstract of the Japanese Patent Application No. 2015-162129, filed on Aug. .

Claims (11)

A liquid crystal alignment agent comprising at least one polyimine-based polymer selected from the group consisting of polylysine and polyamidene obtained by imidating the polyphosphonium amide. The proline acid is obtained by reacting a diamine component containing a diamine compound with a tetracarboxylic dianhydride component having a bond dissociation barrier of a triplet state calculated by Gaussian 09 of 30 kcal/mol or less. Knot. The liquid crystal alignment agent of claim 1, wherein the diamine compound has a diamine having an acetophenone structure, a carbonyl carbon in the acetophenone structure, and a bond with the α carbon in an excited triplet state The dissociation barrier is 30 kcal/mol or less. The liquid crystal alignment agent of claim 2, wherein the diamine compound is a diamine represented by any one of the following formulas, (wherein X ₁ represents a group consisting of a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O-, -COO-, and -OCO- At least one selected, X ₂ represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring, and when X ₂ is cyclohexane When ringing, it can pass 4- The ketone skeleton and the spiro bond are bonded to each other, and the X _{3 group} represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring, when X ₂ When X ₃ is a cyclic group, any hydrogen atom on the cyclic group may be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a fluorine-containing alkyl group having 1 to 3 carbon atoms. Substituted with a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom, and X ₄ represents an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, and an alkoxy group having 1 to 18 carbon atoms. At least one selected from the group consisting of a fluorine-containing alkoxy group having 1 to 18 carbon atoms, X ₅ represents a single bond, -O-, -CH ₂ -, or -COO-, and T represents a carbon number 1 to 6 alkylene, R ₁ represents -OH, -Ph, -OPh, or alkoxy of carbon 1 to 4, and R ₂ represents a hydrogen atom, -Ph, an alkyl group having 1 to 4 carbon atoms or The carbon number is 1 to 4 alkoxy groups, and R ₃ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and R ₄ and R ₅ each independently represent a hydrogen atom or a carbon number of 1 to 2; 4 alkyl, Y represents -CH ₂ - or -O-). The liquid crystal alignment agent of claim 2, wherein the diamine compound is a diamine represented by the following formula (1), (wherein X ₁ represents a group consisting of a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O-, -COO-, and -OCO- At least one selected, X ₂ represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring, and when X ₂ is cyclohexane When ringing, it can pass 4- The ketone skeleton and the spiro bond are bonded to each other, and the X _{3 group} represents a single bond or at least one divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a hetero ring, when X ₂ When X ₃ is a cyclic group, any hydrogen atom on the cyclic group may be an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a fluorine-containing alkyl group having 1 to 3 carbon atoms. Substituted with a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom, and X ₄ represents an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, and an alkoxy group having 1 to 18 carbon atoms. At least one selected from the group consisting of a fluorine-containing alkoxy group having 1 to 18 carbon atoms. The liquid crystal alignment agent of claim 3 or 4, wherein X ₂ in the above diamine compound formula (1) is a cyclohexane ring and is transmitted through 4- A diamine compound in which a ketone skeleton and a spiro bond are bonded to each other. The liquid crystal aligning agent of Claim 4 or 5, wherein the diamine compound represented by the above formula (1) is a diamine represented by any one of the following formulas, but n in the following formula is an integer of 1 to 18, The liquid crystal alignment agent according to any one of claims 1 to 6, wherein the total diamine component contains 5 to 60 mol% of the diamine compound. The liquid crystal alignment agent according to any one of claims 1 to 7, further comprising a polymerizable compound having a group capable of photopolymerization or photocrosslinking at two or more terminals. A liquid crystal alignment film obtained by the liquid crystal alignment agent according to any one of claims 1 to 8. A liquid crystal display element comprising the liquid crystal alignment film of claim 9. The liquid crystal display element of claim 10, wherein the liquid crystal display element is in a PSA mode.