TWI485201B - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

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

The present invention relates to a liquid crystal alignment agent used in the production of a liquid crystal alignment film, a liquid crystal alignment film using the same, and a liquid crystal display element.

Liquid crystal display elements used in LCD TVs, LCD monitors, etc., have now been implemented as thin. A lightweight display device is widely used. As a liquid crystal alignment film for aligning liquid crystals, it is mainly used for coating a polyimide substrate with a polyamidene precursor such as polyamidic acid (also known as polyamidic acid) or polyamidomate or a polyimine. The solution is a liquid crystal alignment agent which is a main component and is fired into a so-called polyamidimide liquid crystal alignment film.

In order to improve the display characteristics of these liquid crystal display elements, by changing the structure of polyglycolic acid, polyamidomate or polyimine, polyglycolic acid, polyperurate or polypyrene having different properties are added. A method such as an amine blend or an additive is used to improve the liquid crystal alignment property, electrical properties, and the like, and control the pretilt angle (see Patent Document 1).

[Previous Technical Literature] [Patent Document]

Patent Document 1: JP-A-2011-100099

However, as the performance of the liquid crystal display element is increased, the area is increased, and the power saving of the display device progresses, the characteristics required for the liquid crystal alignment film are also severe, and the resistance of the liquid crystal display element to ultraviolet light is also required. . Specifically, for example, in liquid crystal injection. When the dropping method is applied during the encapsulation, when the sealing material for encapsulation is irradiated with ultraviolet rays, the liquid crystal alignment film in the image forming region may be irradiated with ultraviolet rays. Further, when the liquid crystal alignment film is aligned by light irradiation, the liquid crystal alignment film is irradiated with ultraviolet rays (UV) in the alignment treatment step. Therefore, in a liquid crystal display device of a vertical alignment (VA) method, a step of irradiating ultraviolet rays while applying a voltage to liquid crystal molecules is also included in the manufacturing process. In addition, there are cases where the liquid crystal display element is exposed to ultraviolet rays from the outside during use. When the liquid crystal alignment film is not resistant to the exposure of such ultraviolet rays, there is a problem that electrical characteristics such as voltage holding ratio are deteriorated.

An object of the present invention is to provide a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element which can obtain a liquid crystal alignment film excellent in ultraviolet resistance, in order to solve the problems of the prior art described above.

As a result of active research by the present inventors, it has been found that polyamine or polyimine containing a specific structure of tetracarboxylic dianhydride as a raw material The liquid crystal alignment agent with a solvent is extremely effective for achieving the above problems, and thus the present invention has been completed.

That is, the present invention has the following points.

A liquid crystal alignment agent comprising a polyamine acid obtained by polymerizing a tetracarboxylic dianhydride represented by the following formula (1) and a diamine component, and a polyamic acid At least one polymer and solvent of the polyimine obtained by imidization

2. The liquid crystal alignment agent according to 1, wherein the polymer is polyimine.

A liquid crystal alignment film which is obtained by using a liquid crystal alignment agent as described in 1 or 2.

A liquid crystal display device comprising the liquid crystal alignment film according to 3 above.

The liquid crystal alignment film obtained by using the liquid crystal alignment agent of the present invention is excellent in resistance to ultraviolet rays. Therefore, it can be provided, for example, even as A liquid crystal display element which is used in a liquid crystal alignment film of a liquid crystal display element which is irradiated with an ultraviolet ray during the manufacturing process, and which is deteriorated in electrical characteristics such as a voltage holding ratio during the manufacturing process, and which has good electrical characteristics. In addition, it is a liquid crystal display element which has deterioration of electrical characteristics such as a voltage holding ratio and is excellent in electrical characteristics, even when it is used as a liquid crystal alignment film which is exposed to a liquid crystal display element used in an ultraviolet ray environment.

The invention is described in detail below.

The liquid crystal alignment agent of the present invention contains a polyamic acid selected from the group consisting of a polymerization reaction of a tetracarboxylic dianhydride represented by the above formula (1) and a diamine component, and imidization of the polyphosphonium amide. At least one polymer of polyimine, and a solvent. Further, the liquid crystal alignment agent is a solution for producing a liquid crystal alignment film, and the liquid crystal alignment film is a film for aligning liquid crystals in a specific direction.

In the formula (1), -NH- bonded to the benzene ring preferably exists in the para or meta position.

Polylysine is obtained by polymerizing a tetracarboxylic dianhydride represented by the formula (1) with a diamine component. Further, the obtained polylysine is imidized by hydrazine to obtain a polyimine.

Therefore, the liquid crystal alignment agent of the present invention contains a polyamic acid obtained by polymerizing the tetracarboxylic dianhydride represented by the formula (1) and a diamine component, or imidizing the polyphosphonium amide. The obtained polyimine and the solvent. By using a tetracarboxylic dianhydride represented by the formula (1) As a raw material of polyphosphonic acid or a liquid crystal alignment agent of a polyimine and a solvent, as shown in the examples below, excellent ultraviolet (UV) resistance and voltage retention (VHR) due to exposure to UV can be obtained. A liquid crystal alignment film in which deterioration of electrical characteristics is suppressed. Therefore, it is possible to provide a liquid crystal display element which is suppressed in electrical characteristics such as voltage holding ratio and which has excellent electrical characteristics even when it is irradiated with UV in a manufacturing process and used in an environment exposed to UV.

In addition, a liquid crystal alignment agent containing a polyimine and a solvent of a tetracarboxylic dianhydride represented by (1) as a raw material has a uniform coating film uniformity when a liquid crystal alignment agent is applied, that is, a coating film. It is difficult for polymer agglomerates (also known as whitening and agglomeration) to occur at the ends of the surface. Of course, a liquid crystal alignment agent containing a polyamic acid and a solvent containing a tetracarboxylic dianhydride represented by the formula (1) as a raw material is also difficult to produce the whitening. Condensed. Further, the solubility of the polyimine which is a tetracarboxylic dianhydride represented by the formula (1) as a raw material for a solvent used in a liquid crystal alignment agent such as N-methyl-2-pyrrolidone or 2-butoxyethanol High, even if the liquid crystal alignment agent is left for a long time, it will not precipitate, and the storage stability is high.

Further, the method for producing the tetracarboxylic dianhydride represented by the formula (1) is not particularly limited, and for example, by using 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride 4-chloride and Manufactured by reacting phenylenediamine. Specifically, the production method described in JP-A-2012-72121 is exemplified.

Further, the tetracarboxylic dianhydride represented by the formula (1) may be combined with a tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the formula (1) (hereinafter also referred to as other tetracarboxylic dianhydride). Reacts with the diamine component. At this time, (1) The tetracarboxylic dianhydride is preferably used in an amount of 60 to 95 mol% of the total amount of the tetracarboxylic dianhydride component used in the synthesis of the polyamic acid, and more preferably 70 of the tetracarboxylic dianhydride component. ~90 mol% is a tetracarboxylic dianhydride represented by the formula (1). Further, the tetracarboxylic dianhydride represented by the formula (1) is described as a tetracarboxylic dianhydride component together with other tetracarboxylic dianhydride.

The other tetracarboxylic dianhydride component is exemplified by the tetracarboxylic dianhydride represented by the following formula (2).

(In the formula (2), Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms and containing a non-aromatic cyclic hydrocarbon group having 4 to 6 carbon atoms.

In the formula (2), a specific example of Z ₁ is a tetravalent organic group represented by the following formula (2a) to formula (2j).

(In the formula (2a), Z ₂ to Z ₅ are a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, and may be the same or different. In the formula (2g), Z ₆ and Z ₇ are a hydrogen atom or a methyl group. And can be the same or different).

In the formula (2), the optimum structure of Z ₁ is the formula (2a), the formula (2c), the formula (2d), the formula (2e), the formula (2f) or the formula in terms of polymerization reactivity or ease of synthesis. (2g). Among them, the formula (2a), the formula (2e), the formula (2f) or the formula (2g) is preferred.

Further, the ratio of the tetracarboxylic dianhydride represented by the formula (2) to the total amount of the tetracarboxylic dianhydride component is not particularly limited, and for example, preferably 5 to 40 mol% of the total amount of the tetracarboxylic dianhydride component is The tetracarboxylic dianhydride represented by the above formula (2) is more preferably 10 to 30 mol%.

The tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the above formula (2) is exemplified by pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalene. Tetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-nonanetetracarboxylic acid, 1,2,5,6-nonanedicarboxylic acid, 3,3', 4, 4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyl Tetracarboxylic acid, bis(3,4-dicarboxyphenyl)ether, 3,3',4,4'-benzophenonetetracarboxylic acid, bis(3,4-dicarboxyphenyl)anthracene, bis( 3,4-Dicarboxyphenyl)methane, 2,2-bis(3,4-dicarboxyphenyl)propane, 1,1,1,3,3,3-hexafluoro-2,2-dual (3 , 4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)dimethyloxane, bis(3,4-dicarboxyphenyl)diphenylnonane, 2,3,4,5- Pyridinetetracarboxylic acid, 2,6-bis(3,4-dicarboxyphenyl)pyridine, 3,3',4,4'-diphenylphosphonium tetracarboxylic acid, 3,4,9,10-anthracene A carboxylic acid or a dianhydride of 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid.

In addition, the tetracarboxylic dianhydride represented by the above formula (1) or the other tetracarboxylic dianhydride may be used alone or in combination of two or more kinds, which may be used as a raw material of the polyacrylic acid or the polyimine. .

The diamine component to be reacted with a tetracarboxylic dianhydride component such as tetracarboxylic dianhydride represented by the formula (1) is not particularly limited, and a diamine generally used in a liquid crystal alignment agent can be used. The general diamine is exemplified by a widely used diamine, a diamine having a side chain in which the liquid crystal is vertically aligned, a diamine exhibiting a high pretilt angle to the liquid crystal, or a photoreactive diamine.

Widely used diamines are exemplified by, for example, p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine. , 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol , 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-di Aminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3-'-dimethoxy-4,4'-diaminobiphenyl, 3,3 '-Dihydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-linked Benzene, 3,3'-trifluoromethyl-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'- Diaminobiphenyl, 2,3'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diamine Diphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'- Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 4,4 '-sulfonyldiphenylamine, 3,3'-sulfonyldiphenylamine, bis(4-aminophenyl)decane, bis(3-aminophenyl)decane, dimethyl-bis(4-amine Phenyl) decane, dimethyl-bis(3-aminophenyl)decane, 4,4'-thiodiphenylamine, 3,3'-thiodiphenylamine, 4,4'-diaminodiyl Phenylamine, 3,3'-diaminodiphenylamine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diamine Diphenylamine, N-methyl(4,4'-diaminodiphenyl)amine, N-methyl(3,3'-diaminodiphenyl)amine, N-methyl (3 , 4'-diaminodiphenyl)amine, N-methyl (2,2'-Diaminodiphenyl)amine, N-methyl(2,3'-diaminodiphenyl)amine, 4,4'-diaminobenzophenone, 3,3 '-Diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3'- Diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diamine Naphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis(4-aminophenyl)ethane, 1,2- Bis(3-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,3-bis(3-aminophenyl)propane, 1,4-bis(4- Aminophenyl)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,4-bis(4) -aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-double (4-Aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, 1,3-bis(4-amino Phenoxy)benzene, 4,4'-[1,4-phenylenebis(methylene)]diphenylamine, 4,4'-[1,3-phenylenebis(methylene)] Aniline, 3,4'-[1,4-phenylenebis(methylene)]diphenylamine, 3,4'-[1,3-phenylenebis(methylene)]diphenylamine, 3, 3'-[1,4-phenylenebis(methylene)]diphenylamine, 3,3'-[1,3-phenylenebis(methylene)]diphenylamine, 1,4-phenylene Bis[(4-aminophenyl)methanone], 1,4-phenylene bis[(3-aminophenyl)methanone], 1,3-phenylene bis[(4-amino) Phenyl)methanone], 1,3-phenylene bis[(3-aminophenyl)methanone], 1,4-phenylene bis(4-aminobenzoate), 1,4 - phenyl bis(3-aminobenzoate), 1,3-phenylene bis(4-aminobenzoate), 1,3-phenylene bis(3-aminobenzoate) Acid ester), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalic acid Ester, bis(3-aminophenyl)isophthalate, N,N'-(1,4-phenylene)bis(4-aminobenzamide), N,N'-( 1,3-phenylene) bis(4-aminobenzamide), N, N -(1,4-phenylene)bis(3-aminobenzamide), N,N'-(1,3-phenylene)bis(3-aminobenzamide), N, N'-bis(4-aminophenyl)terephthalamide, N,N'-bis(3-aminophenyl)terephthalamide, N,N'-bis(4-amine Phenyl)m-xylyleneamine, N,N'-bis(3-aminophenyl)m-xylyleneamine, 9,10-bis(4-aminophenyl)anthracene, 4,4 '-Bis(4-Aminophenoxy)diphenylanthracene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-( 4-aminophenoxy)phenyl)hexafluoropropane, 2,2'-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2'-bis(4- Aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 3,5-diamine Benzoic acid, 2,5-diaminobenzoic acid, 1,3-bis(4-aminophenoxy)propane, 1,3-bis(3-aminophenoxy)propane, 1,4- Bis(4-aminophenoxy)butane, 1,4-bis(3-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,5 - bis(3-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,6-bis(3-aminophenoxy)hexane, 1, 7-bis(4-aminophenoxy)heptane, 1,7-(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1, 8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)decane, 1,9-bis(3-aminophenoxy)decane, 1 , 10-(4-aminophenoxy)decane, 1,10-(3-aminophenoxy)decane, 1,11-(4-aminophenoxy)undecane, 1, Aromatic groups such as 11-(3-aminophenoxy)undecane, 1,12-(4-aminophenoxy)dodecane, 1,12-(3-aminophenoxy)dodecane Group diamine, bis(4-aminocyclohexyl)methane Alicyclic diamines such as bis(4-amino-3-methylcyclohexyl)methane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane 1,6-Diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminodecane, 1,10-diaminodecane An aliphatic diamine such as 1,11-diaminoundecane or 1,12-diaminododecane.

These widely used diamines are preferably used in an amount of from 50 to 95 mol%, more preferably from 70 to 90 mol%, of the diamine component used in the synthesis of polyamic acid.

a diamine or a pair of liquid crystals having a side chain for vertically aligning the liquid crystal The diamine exhibiting a high pretilt angle may be exemplified by an alkyl group having a long chain, a group having a ring structure or a branched structure in the middle of a long-chain alkyl group, a steroid group, or a part or all of hydrogen atoms of the groups being substituted with fluorine. The base of the atom acts as a diamine of the side chain. Specific examples thereof include diamines represented by the following formulas (3), (4), (5), and (6), but are not limited thereto.

(In the formula (3), l, m and n each independently represent an integer of 0 or 1, and R ³ represents an alkylene group having 2 to 6 carbon atoms, -O-, -COO-, -OCO-, -NHCO-, -CONH-, or an alkyl-ether group having a carbon number of 1 to 3, and R ⁴ , R ⁵ and R ⁶ each independently represent a phenyl or a cycloalkyl group, and R ⁷ represents a hydrogen atom and a carbon number of 2 to 24. An alkyl group or a fluorine-containing alkyl group, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, or a monovalent large cyclic substituent formed from the above).

Further, R ³ in the above formula (3) is preferably an alkyl group-ether group having -O-, -COO-, -CONH- or a carbon number of 1 to 3 from the viewpoint of easiness of synthesis.

Further, in the case of R ⁴ , R ⁵ and R ⁶ in the formula (3), from the viewpoints of easiness of synthesis and ability to vertically align the liquid crystal, it is preferred that l, m, n, and R ⁴ shown in Table 1 below. , a combination of R ⁵ and R ⁶ .

Further, when at least one of l, m, and n is 1, R ⁷ in the formula (3) is preferably a hydrogen atom or an alkyl group having 2 to 14 carbon atoms or a fluorine-containing alkyl group, more preferably a hydrogen atom or carbon. A number of 2 to 12 alkyl or fluoroalkyl groups. Further, when l, m, and n are all 0, R ^{7 is} preferably an alkyl group having 12 to 22 carbon atoms or a fluorine-containing alkyl group, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, and the like. The one-valent large cyclic substituent is more preferably a 12- to 20-alkyl group or a fluorine-containing alkyl group.

Further, the ability of the polymer having the side chain in which the liquid crystal is vertically aligned to vertically align the liquid crystal differs depending on the structure of the side chain in which the liquid crystal is vertically aligned, but generally, when the amount of the side chain in which the liquid crystal is vertically aligned is large In other words, when the content of the diamine having a side chain in which the liquid crystal is vertically aligned is increased in the diamine component, the ability to vertically align the liquid crystal is improved, and if the content is small, the ability is lowered. Further, when the ring structure is formed, the ability to vertically align the liquid crystals tends to be improved as compared with those having no ring structure.

(In the formulas (4) and (5), A ₁₀ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -CO-, or -NH-, A ₁₁ represents a single bond or a phenyl group, and a represents -R ³ -(R ⁴ ) _l -(R ⁵ ) _m -(R ⁶ ) _n -R ⁷ (R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ And l, m, and n are the same as defined in the above formula (3), and a' represents a divalent group of a structure in which an element such as a hydrogen atom is removed from the same structure as the above a).

(In the formula (6), A ₁₄ is an alkyl group having 3 to 20 carbon atoms which may be substituted by a fluorine atom, A ₁₅ is a 1,4-alkylene group or a 1,4-phenyl group, and A ₁₆ is an oxygen atom. Or -COO-* (except that the "*" key bond is bonded to A ¹⁵ ), A ₁₇ is an oxygen atom, or -COO-* (except for the "*" bond bond and (CH) ₂ ) a ₂ bond). In addition, a ₁ is 0 or 1, a ₂ is an integer of 2 to 10, and a ₃ is 0 or 1).

The bonding position of the two amine groups (-NH ₂ ) in the formula (3) is not limited, and is specifically exemplified as relative to the side chain (-R ³ -(R ⁴ ) _l -(R ⁵ ) _m -(R ⁶ _n -R ⁷ ) is at the 2, 3 position, 2, 4 position, 2, 5 position, 2, 6 position, 3, 4 position, 3, 5 position on the benzene ring. Among them, the 2, 4 position, the 2, 5 position, or the 3, 5 position is preferable from the viewpoint of reactivity in synthesizing polyamic acid. If it is desired to increase the ease of synthesizing the diamine, it is preferably 2, 4 or 3, 5 positions.

The specific structure of the formula (3) is exemplified by the diamine represented by the following formula [A-1] to the formula [A-24], but is not limited thereto.

(In the formula [A-1] to the formula [A5], A ₁ is an alkyl group having 2 to 24 carbon atoms or a fluorine-containing alkyl group).

(In the formula [A-6] and the formula [A-7], A ₂ represents -O-, -OCH ₂ -, -CH ₂ O-, -COOCH ₂ -, or -CH ₂ OCO-, and A ₃ is carbon Alkyl groups of 1 to 22, alkoxy groups, fluorine-containing alkyl groups or fluorine-containing alkoxy groups).

(In the formula [A-8]~Form [A-10], A ₄ represents -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O -, -OCH ₂ - or -CH ₂ -, A ₅ is an alkyl group having 1 to 22 carbon atoms, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group).

(In the formula [A-11] and the formula [A-12], A ₆ represents -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O -, -OCH ₂ -, -CH ₂ -, -O- or -NH-, A ₇ is a fluorine group, a cyano group, a trifluoromethyl group, a nitro group, an azo group, a methyl group, an ethyl group, an ethyl group Oxy or hydroxy).

(In the formula [A-13] and the formula [A-14], A ₈ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerization of 1,4-cyclohexylene is trans isomer ()).

(Formulae [A-15] and [A-16], A ₉ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomer of 1,4-cyclohexylene is a cis isomer) .

Specific examples of the diamine represented by the formula (4) include the diamines represented by the following formulas [A-25] to [A-30], but are not limited thereto.

(In the formula [A-25]~Form [A-30], A ₁₂ represents -COO-, -OCO-, -CONH-, -NHCO-, -CH ₂ -, -O-, -CO- or -NH -, A ₁₃ represents an alkyl group having 1 to 22 carbon atoms or a fluorine-containing alkyl group).

Specific examples of the diamine represented by the formula (5) include a diamine represented by the following formula [A-31] to the formula [A-32], but are not limited thereto.

Among them, [A-1], [A-2], [A-3], [A-4], [A-5], [from the viewpoint of the ability of the liquid crystal to vertically align and the liquid crystal response speed. The diamines of A-25], [A-26], [A-27], [A-28], [A-29], and [A-30] are preferred.

The diamine having a side chain for vertically aligning the liquid crystals or the diamine exhibiting a high pretilt angle to the liquid crystal is preferably used in an amount of from 0 to 50 mol% of the diamine component used in the synthesis of the polylysine. More preferably 10 to 40 mol% of the diamine component.

The diamine having a photoreactive group may be exemplified by having a vinyl group, an acrylonitrile group, a methacryloyl group, an allyl group, a styryl group, a lauryl group, a chalcone group, a coumarin group, and a horse. a photoreactive group of an imine group or the like as a side chain diamine, for example, represented by the following formula (7) The diamine is shown, but is not limited thereto.

(R ⁸ in the formula (7) represents a monovalent or -CH ₂ -, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, -N ( Any of CH ₃ )-, -CON(CH ₃ )-, -N(CH ₃ )CO-, R ⁹ represents a single bond, or an alkylene having 1 to 20 carbon atoms which are unsubstituted or substituted by a fluorine atom. And the alkyl group-CH ₂ - may be optionally substituted by -CF ₂ - or -CH=CH-, and any of the groups listed below may be substituted with each other unless otherwise adjacent to each other; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocyclic ring, a divalent heterocyclic ring. R ¹⁰ is a vinyl group, an acrylonitrile group, a methacryl fluorenyl group, an allyl group, Styryl group, -N(CH ₂ CHCH ₂ ) ₂ , or a structure represented by the following formula).

Further, R ⁸ in the above formula (7) can be formed by a usual organic synthesis method, but from the viewpoint of easiness of synthesis, -CH ₂ -, -O-, -COO-, -NHCO-, -NH-, -CH ₂ O-.

Further, the carbon ring or heterocyclic ring of the divalent carbon ring or the divalent hetero ring which is substituted for any -CH ₂ - of R ⁹ is specifically exemplified by the following structure, but is not limited thereto.

R ¹⁰ is preferably a vinyl group, an acrylonitrile group, a methacryl fluorenyl group, an allyl group, a styryl group, -N(CH ₂ CHCH ₂ ) ₂ or a formula represented by the following formula from the viewpoint of photoreactivity. structure.

Further, -R ⁸ -R ⁹ -R ^{10 of the} above formula (7) is more preferably the following structure.

The bonding position of the two amine groups (-NH ₂ ) in the formula (7) is not limited. Specifically, it is exemplified as 2, 3 position, 2, 4 position, 2, 5 position, 2, 6 position, 3, 4 position, 3 on the benzene ring with respect to the side chain (-R ⁸ -R ⁹ -R ¹⁰ ). , 5 positions. Among them, the 2, 4 position, the 2, 5 position, or the 3, 5 position is preferable from the viewpoint of reactivity in synthesizing polyamic acid. If it is desired to increase the ease of synthesizing the diamine, it is preferably 2, 4 or 3, 5 positions.

The diamine having a photoreactive group is specifically exemplified by the following combination Things, but not limited to this.

(wherein, X represents a single bond, or a bond group selected from -O-, -COO-, -NHCO-, -NH-, and Y represents a single bond, or a carbon number which is unsubstituted or substituted by a fluorine atom ~20 alkyl group).

Further, the diamine having such a photoreactive group is preferably used in an amount of from 0 to 70 mol%, more preferably from 0 to 60 mol%, based on the diamine component used for the synthesis of polyglycine.

The diamine may be used alone or in combination of two or more kinds depending on characteristics such as liquid crystal alignment property, pretilt angle, voltage holding property, cumulative charge, and liquid crystal response speed when used as a liquid crystal display element.

The polymerization of the diamine component and the tetracarboxylic dianhydride component is usually carried out in an organic solvent. The organic solvent to be used at this time is not particularly limited as long as it can dissolve the produced polyamic acid. Specific examples are N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrole Alkanone, N-methyl caprolactam, dimethyl hydrazine, tetramethyl urea, pyridine, dimethyl hydrazine, γ-butyrolactone, isopropanol, methoxymethylpentanol, dipentane Alkene, ethyl amyl ketone, methyl decyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve Acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol Monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene Alcohol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, two Propylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether , ethyl isobutyl ether, diisobutylene, amyl acetate Butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, ring Hexone, ethyl carbonate, propyl carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate , 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid methyl ethyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3 - propyl methoxypropionate, butyl 3-methoxypropionate, diglyme or 4-hydroxy-4-methyl-2-pentanone. These may be used singly or in combination. Further, even a solvent which does not dissolve the polyamic acid may be used in the above solvent without being precipitated in the range in which the produced polyaminic acid is precipitated. And, there is Since the water in the organic solvent is a cause of hindering the polymerization reaction and further hydrolyzing the produced polylysine, the organic solvent is preferably used by dehydration.

When the diamine component and the tetracarboxylic dianhydride component are reacted in an organic solvent, a method in which a diamine component is dispersed or dissolved in an organic solvent is stirred, and a tetracarboxylic dianhydride component is directly added. Or a method of dispersing or dissolving in an organic solvent and adding it, and conversely adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic dianhydride in an organic solvent, and a tetracarboxylic dianhydride component and Any of these methods may be used as a method of mutually adding diamine components. Further, when a plurality of kinds of diamine components or tetracarboxylic dianhydride components are used for the reaction, they may be reacted in a state of being mixed in advance, or may be reacted individually or sequentially, or a low molecular weight body obtained by reacting each other may be further carried out. Mix the reaction. The polymerization temperature at this time may be any temperature from -20 ° C to 150 ° C, but preferably in the range of from -5 ° C to 100 ° C. Further, the reaction can be carried out at any concentration. However, when the concentration is too low, it is difficult to obtain a high molecular weight poly-proline (further, polyimine). When the concentration is too high, the viscosity of the reaction liquid becomes too high and it is difficult to uniformly stir. Therefore, the total concentration of the diamine component and the tetracarboxylic dianhydride component is preferably from 1 to 50% by mass, more preferably from 5 to 30% by mass, based on the total amount of the reaction solution. The initial stage of the reaction is carried out at a high concentration, and then an organic solvent can be added.

In the polymerization reaction of poly-proline, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic dianhydride component is preferably from 0.8 to 1.2. As with the usual polycondensation reaction, the closer the molar ratio is to 1.0, the greater the molecular weight of the polyglycine produced.

The polyamic acid thus polymerized is, for example, a polymer having a repeating unit represented by the following formula [a].

(In the formula [a], R ₁₁ is a tetravalent organic group derived from a tetracarboxylic dianhydride component such as tetracarboxylic dianhydride represented by the above formula (1), and R ₁₂ is a diamine derived from a raw material. The divalent organic group of the component H ₂ NR ₁₂ -NH ₂ , j represents a positive integer).

In the above formula [a], R ₁₁ and R ₁₂ may each be a polymer of the same repeating unit of one type, and may also be a polymerization of a plurality of repeating units having different structures of R ₁₁ or R ₁₂ . Things.

Next, the polyamidiamine is obtained by dehydrating the polyamic acid ring.

The method for imidizing polyphosphonium amide is exemplified by thermal imidization of a polyglycine solution directly by heating, or imidization of a catalyst by adding a catalyst to a polyaminic acid solution.

The temperature at which the polyaminic acid is thermally imidized in the solution is from 100 ° C to 400 ° C, preferably from 120 ° C to 250 ° C, and the water formed by the imidization reaction is preferably discharged outside the system. And proceed.

The imidization of the polyaminic acid catalyst can be carried out by adding a basic catalyst and an acid anhydride to the polyamic acid solution, and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. The amount of the alkaline catalyst is 0.5 to 30 moles of the proline group, preferably 2 to 20 moles, and the amount of the anhydride is 1 to 50 moles of the amidate group, preferably 3 to 30. Moer times. The basic catalyst may, for example, be pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is preferred because it has moderate alkalinity for carrying out the reaction. The acid anhydride may, for example, be acetic anhydride, trimellitic anhydride or pyromellitic anhydride, and in the case where acetic anhydride is used, purification after completion of the reaction becomes easy. 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 resulting polymer (polyimine or polylysine) is recovered from a reaction solution of a polymer (polyimine or polylysine), the reaction solution may be precipitated by putting it into a solvent. The solvent used for the precipitation may, for example, be methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene or water. The polymer precipitated in the solvent and recovered by filtration can be dried at normal temperature or under reduced pressure under normal pressure or reduced pressure. Moreover, when the polymer recovered by precipitation is repeatedly dissolved in an organic solvent and re-precipitated and recovered for 2 to 10 times, impurities in the polymer can be reduced. The solvent in this case is, for example, an alcohol, a ketone or a hydrocarbon. When three or more solvents selected from the above are used, it is preferable because the purification efficiency can be further improved.

The dehydration ring closure ratio (the imidization ratio) of the proline group of the polyimine contained in the liquid crystal alignment agent of the present invention need not necessarily be 100% can be arbitrarily selected in the range of 0% to 100% depending on the purpose or purpose, but preferably 50% to 90%, more preferably 70% to 86%.

In addition, when the molecular weight of the polyamic acid or the polyimine is considered in consideration of the strength of the obtained polymer film (liquid crystal alignment film), workability at the time of formation of a polymer film, and uniformity of a polymer film, GPC (gel) The weight average molecular weight measured by the permeation chromatography method is preferably from 5,000 to 1,000,000, more preferably from 10,000 to 150,000.

Solvent

Further, the solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it can dissolve the above polyimine or polylysine, and is exemplified by N,N-dimethylformamide, N,N-di Methylacetamide, N-methyl-2-pyrrolidone, N-methyl caprolactam, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinylpyrrolidone, dimethyl azine, tetra Methyl urea, pyridine, dimethyl hydrazine, hexamethylarylene, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl decyl ketone, methyl ethyl Ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethyl carbonate, propyl carbonate, diglyme and 4-hydroxy-4-methyl-2-pentyl An organic solvent such as a ketone. These may be used singly or in combination.

The solvent in the liquid crystal alignment agent of the present invention preferably has a solvent content of from 70 to 99% by mass from the viewpoint of coating to form a uniform polymer film. This content can be appropriately changed depending on the film thickness of the target liquid crystal alignment film.

<Ingredients of Other Liquid Crystal Aligning Agents>

The polymer component of the liquid crystal alignment agent of the present invention may be selected only from a polyamic acid obtained by polymerizing a tetracarboxylic dianhydride represented by the above formula (1) and a diamine component, and the polyfluorene is obtained. At least one polymer of the polyimine obtained by imidization of ruthenium amide may be selected from the group consisting of polymerizing a tetracarboxylic dianhydride represented by the above formula (1) with a diamine component. At least one polymer of polyamic acid and polyimine obtained by imidating the polyphosphonium is mixed with other polymers. In this case, the polyamic acid obtained by polymerizing a tetracarboxylic dianhydride represented by the above formula (1) and a diamine component are obtained, and the polyphosphonium amide is imidized. The total amount of at least one polymer of the polyimine is 0.5 to 15% by mass, preferably 1.0 to 10% by mass, based on the other polymer. Other polymers other than this are polyacrylamide or polyimine which is obtained from a tetracarboxylic dianhydride component and a diamine component which do not contain the tetracarboxylic dianhydride represented by the above formula (1). Further, polymers other than polyamine and polyimine are specifically exemplified by polyphthalate, acrylic polymer, methacrylic polymer, polystyrene or polyamine.

The liquid crystal alignment agent of the present invention may contain an organic solvent (also referred to as a weak solvent) which improves the film thickness uniformity or surface smoothness of the polymer film when the liquid crystal alignment agent is applied, without impairing the effects of the present invention. Compound. Further, a compound or the like which improves the adhesion between the liquid crystal alignment film and the substrate may be contained.

Specific examples of the weak solvent for improving film thickness uniformity or surface smoothness are isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, and ethyl group. Cellulolytic, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, 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 single Methyl 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 Ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone , methylcyclohexene, propyl ether, dihexyl ether, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate Ester, acetic acid Propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3- Ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxyl 2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2 - acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate An organic solvent having a low surface tension such as n-butyl lactate or isoamyl lactate.

These weak solvents may be used in one type or in a plurality of types. use. When the weak solvent as described above is used, it is preferably from 5 to 80% by mass, more preferably from 20 to 60% by mass, based on the total of the organic solvent contained in the liquid crystal alignment agent.

The compound which improves film thickness uniformity or surface smoothness is exemplified by a fluorine-based surfactant, a polyfluorene-based surfactant, a nonionic surfactant, and the like. More specifically, for example, EF TOP EF301, EF303, EF352 (manufactured by TOKEMU PRODUCTS), MEGAFAC F171, F173, R-30 (made by Dainippon Ink), FLORARD FC430, FC431 (manufactured by Sumitomo 3M), ASAHI GUARD AG710, SURFLON S- 382, SC101, SC102, SC103, SC104, SC105, SC106 (asahi Glass system). The use ratio of the surfactant is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

The compound which improves the adhesiveness of a liquid crystal alignment film and a substrate is a compound containing a functional decane or the compound containing an epoxy group, for example, 3-aminopropyl trimethoxy decane, 3-aminopropyl three Ethoxy decane, 2-aminopropyltrimethoxydecane, 2-aminopropyltriethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-Aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N- Ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-ethoxycarbonyl-3-aminopropyltriethoxydecane, N-triethoxydecylpropyltrisethyltriamine, N-trimethoxydecylpropyltrisoleethyltriamine, 10-trimethoxydecyl-1,4,7-triazadecane, 10-triethoxydecyl-1,4,7 - triazadecane, 9-trimethoxydecyl acetate-3,6-diazadecyl acetate, 9-triethoxydecane acetate 3-,6-diazadecyl ester, N-benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropyltriethoxydecane, N-phenyl 3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane, N-bis(oxyethylidene)-3-aminopropyltrimethoxydecane, N-bis(oxyethylidene)-3-aminopropyltriethoxydecane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl Ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromo neopentyl glycol condensate Glycerol ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3- Bis(N,N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and the like.

When the compound to be adhered to the substrate is used, it is preferably from 0.1 to 30 parts by mass, more preferably from 1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. When the amount is less than 0.1 part by mass, the adhesion improving effect cannot be expected, and when it is more than 30 parts by mass, the liquid crystal alignment property may be deteriorated.

In addition to the above-mentioned weak solvent and compound, the liquid crystal alignment agent of the present invention may be added to change the dielectric properties or electrical conductivity of the liquid crystal alignment film, without impairing the effects of the present invention. Electrical or conductive material.

<Liquid alignment film. Liquid crystal display element〉

The liquid crystal alignment agent of the present invention can be applied to a substrate, fired, and subjected to alignment treatment such as rubbing treatment or light irradiation to be used as a liquid crystal alignment film. Further, in the case of vertical alignment use or the like, it can be used as a liquid crystal alignment film even without alignment treatment. The substrate to be used in this case is not particularly limited as long as it is a substrate having high transparency, but a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used in addition to the glass substrate. From the viewpoint of process simplification, it is preferred to use a substrate on which an ITO (Indium Tin Oxide) electrode or the like for liquid crystal driving is formed. Further, in the case of a reflective liquid crystal display device, an opaque substrate such as a germanium wafer may be used as the single-sided substrate. In this case, a material such as aluminum that reflects light may be used.

The coating method of the liquid crystal alignment agent is not particularly limited, and industrially, it is generally carried out by screen printing, lithography, flexographic printing or ink jet printing. Other coating methods include a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray coating method, and the like, and these may be used depending on the purpose. The above liquid crystal alignment agent of the present invention is whitened. Since the aggregation is suppressed, for example, even when the plating time is applied to the substrate or the like, the liquid crystal alignment film having excellent uniformity or transparency can be produced.

The drying step after the liquid crystal alignment agent is applied onto the substrate is not necessarily required, but the time from the application to the time before the firing is not uniform for each substrate, or when it is not fired after coating, it is preferably dried. step. The drying means is not particularly limited as long as the solvent can be removed to such an extent that the shape of the coating film is not deformed by the transfer of the substrate or the like. For example, it is dried on a hot plate at a temperature of 40 ° C to 150 ° C, preferably 60 ° C to 100 ° C for 0.5 to 30 minutes, preferably 1 to 5 minutes.

The coating film formed by coating the liquid crystal alignment agent by the above method can be used as a liquid crystal alignment film (polymer film). At this time, the firing temperature may be carried out at any temperature of from 100 ° C to 350 ° C, but is preferably from 140 ° C to 300 ° C, more preferably from 150 ° C to 230 ° C, and even more preferably from 160 ° C to 220 ° C. The firing can be carried out at any time from 5 minutes to 240 minutes. It is preferably from 10 to 90 minutes, more preferably from 20 to 80 minutes. The heating can be carried out by a conventional method such as a hot plate, a heat cycle type oven or an IR (infrared) type oven, a conveyor belt furnace or the like. When the thickness of the liquid crystal alignment film after firing is too thick, the power consumption of the liquid crystal display element becomes unfavorable, and when the thickness of the liquid crystal display element is too thin, the reliability of the liquid crystal display element is lowered, so it is preferably 5 to 300 nm, more preferably. It is 10~100nm. When the liquid crystal is aligned horizontally or obliquely, the fired liquid crystal alignment film is treated by rubbing or polarized ultraviolet light irradiation or the like. The liquid crystal alignment film using the liquid crystal alignment agent of the present invention also has excellent UV resistance when treated by such polarized ultraviolet irradiation, so that deterioration of electrical characteristics such as voltage holding ratio due to polarized ultraviolet irradiation is suppressed, and is good. Electrical characteristics.

In the liquid crystal display device of the present invention, a substrate having a liquid crystal alignment film is obtained from the liquid crystal alignment agent of the present invention by the above method, and a liquid crystal cell is produced by a known method to form a liquid crystal display element. In an example, the liquid crystal cell having the two substrates arranged in the opposite direction, the liquid crystal layer provided between the substrates, and the liquid crystal cell having the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention between the substrate and the liquid crystal layer is provided. Liquid crystal display element. The liquid crystal display element of the present invention is exemplified by a twisted nematic (TN: Twisted Nematic) method and a vertical alignment (VA: Vertical Aligment). Various types such as IPS: In-Plane Switching (OC): OCB (Optically Compensated Bend).

The method for producing the liquid crystal cell is exemplified by preparing a pair of substrates on which the liquid crystal alignment film is formed, and spreading the spacer on the liquid crystal alignment film of one of the substrates so that the liquid crystal alignment film surface is inside, and bonding the other substrate. A method of injecting a liquid crystal and sealing it under reduced pressure, or a method in which a liquid crystal is dropped on a liquid crystal alignment film surface on which a separator is dispersed, and a substrate is bonded and sealed.

Further, in the liquid crystal display device in which the liquid crystal molecules are aligned in the vertical alignment direction of the substrate by the electric field, the PSA is polymerized in the liquid crystal composition in advance (Polymer Sustained) In the case of an Alignment) liquid crystal display or an SC-PVA liquid crystal display to be added to a liquid crystal alignment film (liquid crystal alignment agent), the liquid crystal is injected between one of the substrates to which the liquid crystal alignment film is formed, and the like. The polymerizable compound may be polymerized by applying ultraviolet light while applying a voltage to the liquid crystal alignment film and the liquid crystal. Even when the ultraviolet ray is irradiated in this way, the liquid crystal alignment film using the liquid crystal alignment agent of the present invention is excellent in UV resistance, so that deterioration of electrical characteristics such as voltage holding ratio due to ultraviolet irradiation is suppressed, and excellent electrical characteristics are obtained.

As the liquid crystal, a positive type liquid crystal having a positive dielectric anisotropy or a negative type liquid crystal having a negative dielectric anisotropy can be used, and specifically, for example, MLC-2003, MLC-6608, MLC-6609 manufactured by Merck Co., Ltd., or the like can be used.

As described above, the liquid crystal display element produced by using the liquid crystal alignment agent of the present invention has a liquid crystal alignment film which is excellent in ultraviolet resistance, so that it can be used as a liquid crystal alignment film of a liquid crystal display element used in an environment exposed to ultraviolet rays. It is suppressed that electrical characteristics such as voltage holding ratio are deteriorated, and it is excellent in electrical characteristics and excellent in reliability.

Example

The invention is illustrated in more detail below by way of examples. Further, the invention is not limited to the interpreters. The abbreviations used in the examples and comparative examples are as follows.

<tetracarboxylic dianhydride>

PPHT: N,N'-bis(1,2-cyclohexanedicarboxylic anhydride-4-yl)carbonyl-1,4-phenylenediamine represented by the following formula

PSHT: N,N'-bis(1,2-cyclohexanedicarboxylic anhydride-4-yl)carbonyl-3,3'-diaminodiphenylanthracene represented by the following formula

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

TDA: 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride

<Diamine>

BAPU: 1,3-bis(4-aminophenethyl)urea

DDM: 4,4'-diaminodiphenylmethane

DADA: N,N-diallyl-2,4-diaminoaniline

APC16: 1,3-diamino-4-hexadecyloxybenzene

APC18: 1,3-diamino-4-octadecyloxybenzene

p-PDA: p-phenylenediamine

<Organic solvents>

NMP: N-methyl-2-pyrrolidone

BCS: 2-butoxyethanol

Hereinafter, the measurement method performed in the present embodiment will be described.

<Measurement of molecular weight>

The molecular weight of poly-proline and polyimine is determined by GPC (normal temperature gel permeation chromatography) apparatus, and the polyamine or polyimine is measured by polyethylene glycol or polyethylene oxide. Number average molecular weight and weight average molecular weight.

GPC device: manufactured by Shodex (GPC-101)

Pipe column: made by Shodex (series of KD803, KD805)

Column temperature: 50 ° C

Dissolution: N,N-dimethylformamide (as an additive, lithium bromide monohydrate (LiBr.H ₂ O) is 30 mmol/L, anhydrous phosphate crystal (original phosphoric acid) is 30 mmol/L , tetrahydrofuran (THF) is 10ml / L)

Flow rate: 1.0ml/min

Standard sample for calibration line production: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by Toray Co., Ltd., and polyethylene glycol (molecular weight: about 12,000, 4000, 1000) manufactured by Polymer Laboratory.

<Measurement of the imidization rate of oxime>

The imidization ratio of polyimine was determined as follows.

20 mg of polyimine powder was placed in an NMR sample tube, and 0.53 ml of deuterated dimethyl hydrazine (DMSO-d ₆ , 0.05% TMS (tetramethyl decane) mixture) was added to completely dissolve. This solution was subjected to a 500 MHz proton NMR measurement using a NMR measuring instrument (JNM-ECA500) manufactured by JEOL DATUM. The sulfhydrylation rate is determined by using a proton derived from a structure which has not changed before and after imidization as a reference proton, and the peak integral value of the proton is used and the proline-derived acid is present in the vicinity of 9.5 ppm to 10.0 ppm. The integral value of the proton peak of the NH group is obtained by the following formula.

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

In the above formula, x is the integral value of the proton peak derived from the NH group of the proline, y is the peak integral value of the reference proton, and α is the relative amine of the prolyl (the imidization rate is 0%) The ratio of the number of protons of a proton of an acid NH group.

(Synthesis Example 1)

1.33 g of PPHT was used as the tetracarboxylic dianhydride component, and 0.32 g of p-PDA was used as the diamine component, and reacted in NMP 14.93 g at room temperature for 18 hours to obtain polyglycine (PAA-1). A solution having a solid concentration of 10% by weight.

(Synthesis Example 2~10)

A solution of the polyaminic acid (PAA-2 to PAA-10) of Synthesis Examples 2 to 10 was obtained in the same manner as in the above Synthesis Example 1, except for the composition shown in Table 2.

(Synthesis Example 11)

To 15.1 g of the solution of the polyamic acid (PAA-1) obtained in Synthesis Example 1, 12.59 g of NMP was added and diluted to prepare a polyglycine solution having a solid concentration of 6 wt%. To the polyamic acid solution, 2.95 g of acetic anhydride and 1.37 g of pyridine were added, and the mixture was reacted at 50 ° C for 3 hours to carry out hydrazine imidization. The obtained polyimine solution was cooled to about room temperature, and then poured into 150 g of methanol to recover the precipitated solid matter. Then, the solid matter was washed twice with methanol, and then dried under reduced pressure at 100 ° C to obtain a yellowish powder of polyimine (SPI-1). The result of measuring the imidization ratio of polyimine (SPI-1) was 79%.

(Synthesis examples 12 to 18)

A powder of the polyimine (Synthesis of SPI-2 to SPI-8) of Synthesis Examples 12 to 18 was obtained in the same manner as in the above Synthesis Example 11 except for the composition shown in Table 3.

(Example 1)

To 3.25 g of the solution of the polymer (polyglycine PAA-1) obtained in the above Synthesis Example 1, 3.25 g of NMP was added, and the mixture was stirred at room temperature for 3 hours. At the end of the agitation, the polylysine was completely dissolved. Further, 1.63 g of BCS was added to the solution, and the mixture was stirred at room temperature for 1 hour to obtain a polymer solution (A1) having a solid concentration of 4.0% by weight. This polymer solution becomes a liquid crystal alignment agent for directly forming a liquid crystal alignment film.

(Examples 2 to 7 and Comparative Examples 1 to 2)

The polymer solutions (A2 to A7) of Examples 2 to 7 and the polymer solutions (B1 to B2) of Comparative Examples 1 to 2 were obtained in the same manner as in Example 1 except for the composition shown in Table 4.

(Example 8)

7.50 g of NMP was added to 0.50 g of the polymer (polyimine SPI-1) obtained in the above Synthesis Example 11 and stirred at room temperature for 3 hours. At the end of the agitation, the polyimine was completely dissolved. Further, BCS 2.01g was added to the solution, and the mixture was stirred at room temperature for 1 hour to obtain a solid concentration of 5.0% by weight. Polymer solution (A8). The polymer solution becomes a liquid crystal alignment agent for directly forming a liquid crystal alignment film.

(Examples 9 to 13 and Comparative Examples 3 to 4)

The polymer solutions (A9 to A13) of Examples 9 to 13 and the polymer solutions (B3 to B4) of Comparative Examples 3 to 4 were obtained in the same manner as in Example 8 except for the composition shown in Table 5. Further, in any of Examples 9 to 13, as in Example 8, the polyimine was completely dissolved at the end of the stirring.

[Production of liquid crystal cell]

The polymer solution obtained in Example 1 was filtered through a 1.0 μm filter. (A1), that is, the liquid crystal alignment agent (A1), spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 80 ° C for 80 seconds, and then fired at 230 ° C for 10 minutes to obtain a film thickness of 100 nm. Coating film (polyimine film). After rubbing with a cloth (roller diameter: 120 mm, number of revolutions: 1000 rpm, moving speed: 50 mm/sec, pressing force: 0.3 mm), the polyimide film was subjected to ultrasonic irradiation for 1 minute in pure water and dried at 80 ° C for 10 minutes. In minutes, a liquid crystal alignment film is formed. Two sheets of the substrate with the liquid crystal alignment film were prepared, and a spacer of 6 μm was placed on the liquid crystal alignment film surface of one of the substrates, and then the rubbing directions of the two substrates were orthogonal to each other, leaving a liquid crystal injection port to be sealed. Around, a cell having a cell gap of 6 μm was produced. Liquid crystal (MLC-2003 (C080), manufactured by Merck Co., Ltd.) was vacuum-injected into the cells at a normal temperature, and the injection port was sealed to obtain a liquid crystal cell in which the liquid crystal was subjected to a 90-degree twist (Twist) alignment.

Further, the liquid crystal alignment agents (A2 to A13) obtained in Examples 2 to 13 and the liquid crystal alignment agents (B1 to B4) obtained in Comparative Examples 1 to 4 were also used in the same manner as the liquid crystal alignment agent (A1) obtained in Example 1. Method for making liquid crystal cells.

[Voltage Retention Rate (VHR) Evaluation]

The voltage holding ratio was evaluated by applying a voltage of 4 V to the obtained liquid crystal cell at a temperature of 90 ° C for 60 μs, and measuring the voltage after 16.67 ms, and how long the voltage can be maintained, that is, the fluctuation from the initial value is calculated as the voltage holding ratio. Further, the voltage holding ratio was measured by using a voltage holding ratio measuring device VHR-1 manufactured by Toyo Technic. The evaluation result (described in Table 6 as "initial" Period) is shown in Table 6.

Next, the liquid crystal cell was irradiated with 1 365 nm of ultraviolet light, and the VHR after ultraviolet irradiation was similarly evaluated. The evaluation results (described as "UV1J" in Table 6) are shown in Table 6.

[Evaluation of pretilt angle]

The obtained liquid crystal cell was heated at 120 ° C for 1 hour, and then the pretilt angle was measured. The pretilt angle was measured by Axo Metrix's "Axo Scan" using the Mueller-Matrix method. The results are shown in Table 6.

[白化. Evaluation of condensed properties]

0.1 ml of each of the liquid crystal alignment agents (polymer solutions) obtained in Examples 1 to 13 and Comparative Examples 1 to 4 was dropped on a Cr substrate, and placed in an environment at a temperature of 23 ° C and a humidity of 55%. The microscope was observed near the end of the droplet every 10 minutes. Further, the observation was carried out at 100 times. When the time when the aggregate was generated was 10 minutes or less, it was evaluated as ×, and when it was less than 10 minutes, the evaluation was Δ, and when it was less than 1 hour, the evaluation was ○, and the evaluation was ○ for 3 hours or more, and the evaluation was ◎ for 3 hours or more. The evaluation results are shown in Table 6.

As shown in Table 6, when the liquid crystal alignment agent (polymer solution) of Examples 1 to 13 containing polyglycine or polyimine containing the tetracarboxylic dianhydride represented by the formula (1) as a raw material was used, In Comparative Examples 1 to 4, the change in the voltage holding ratio before and after the ultraviolet irradiation was small, and it was found that the performance deterioration due to the ultraviolet irradiation was remarkably reduced.

In addition, the liquid crystal alignment agent (polymer solution) of Examples 1 to 13 containing polyglycine or polyimine containing the tetracarboxylic dianhydride represented by the formula (1) as a raw material is whitened. In the evaluation of the aggregation characteristics, even if it was left for more than 3 hours, no aggregates were formed at all, and it was found that it had excellent whitening. Condensation characteristics. Further, it was confirmed that the liquid crystal alignment agents of Examples 1 to 13 achieved a good alignment (pretilt angle) of the liquid crystal by the alignment treatment.

Claims (4)

A liquid crystal alignment agent comprising a polyamic acid selected from the group consisting of a polymerization reaction of a tetracarboxylic dianhydride represented by the following formula (1) with a diamine component, and a polyphosphonium amide At least one polymer of a polyamidimide obtained by amination, and a solvent, The liquid crystal alignment agent of claim 1, wherein the polymer is polyimine. A liquid crystal alignment film characterized by using a liquid crystal alignment agent according to claim 1 or 2. A liquid crystal display element characterized by comprising the liquid crystal alignment film of claim 3.