TW201422677A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal alignment agent comprising a solvent and a solvent-soluble polyimide obtained by imidizing a polyamic acid obtained by causing a polymerization reaction between a tetracarboxylic dianhydride that is represented by formula (1) and a diamine component. (In formula (1), W is the structure represented by the formula listed below) W: (In the formula, R1 is a hydrogen atom, -COOH, -N(CH2CH=CH2)2, or -(CH2)n1CH3. n1 is an integer between 0 and 20. R2 is -C(=O)-, -SO2-, -C(CH3)2-, -O-, -CH2-, -NH-, -C2H4-NH-CONH-C2H4-, or -O(CH2)m1O-. m1 is an integer between 1 and 5.)

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 for producing a liquid crystal alignment film, a liquid crystal alignment film using a liquid crystal alignment agent, and a liquid crystal display element.

Liquid crystal display elements used in liquid crystal televisions, liquid crystal displays, and the like are thin and lightweight display devices, and are now widely used. A liquid crystal alignment film which aligns liquid crystals, and a liquid crystal alignment agent containing a polyamido acid, a polyamido acid ester or the like, or a liquid crystal alignment agent containing a polyamidene solution as a main component is mainly applied to the glass. A substrate or the like, a polyimine-based liquid crystal alignment film which is fired.

In order to improve the display characteristics of such a liquid crystal display element, by changing the structure and mixed characteristics of polyaminic acid, polyamidomate or polyimine, polyglycolic acid, polyamidomate or polyfluorene The imine or the addition of an additive or the like improves the liquid crystal alignment property, electrical characteristics, and the like, and controls the pretilt angle and the like (see Patent Document 1, etc.).

[prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-100099

In the liquid crystal alignment agent, when a liquid crystal alignment agent containing a polyimine is applied onto a substrate or the like, agglomerates of a polymer (polyimine) are generated at the end of the coating film surface (also referred to as agglomerate). For whitening and agglutination, it is difficult to obtain a uniform coating film.

An object of the present invention is to solve the problems of the prior art described above, and to provide a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element which are excellent in whitening and aggregation characteristics.

As a result of intensive studies, the present inventors have found that a liquid crystal alignment agent containing a solvent-soluble polyimine with a specific structure of a tetracarboxylic dianhydride as a raw material and a solvent can effectively achieve the above problems, and the present invention has been completed.

In other words, the present invention has the following technical features.

A liquid crystal alignment agent characterized by comprising:

The solvent-soluble polyimide and the solvent obtained by subjecting the polyamic acid obtained by the polymerization of the tetracarboxylic dianhydride and the diamine component represented by the following formula (1) to the ruthenium imidization.

(In the formula (1), W is a structure represented by the following formula).

(wherein R ¹ is a hydrogen atom, -COOH, -N(CH ₂ CH=CH ₂ ) ₂ or -(CH ₂ ) _n1 CH ₃ , n1 is an integer from 0 to 20, and R ² is -C(= O)-, -SO ₂ -, -C(CH ₃ ) ₂ -, -O-, -CH ₂ -, -NH-, -C ₂ H ₄ -NH-CONH-C ₂ H ₄ - or -O ( CH ₂ ) _m1 O-, m1 is an integer from 1 to 5).

2. A liquid crystal alignment film which is obtained by using the liquid crystal alignment agent of the above item 1.

A liquid crystal display device comprising the liquid crystal alignment film of the second aspect.

Since the liquid crystal alignment agent of the present invention is excellent in whitening and aggregation characteristics, it can be produced, for example, after being applied to a substrate or the like for a long period of time, and is also a liquid crystal alignment film having excellent uniformity.

[Formation of the Invention]

The invention is described in detail below.

The liquid crystal alignment agent of the present invention contains a solvent-soluble polyimine obtained by subjecting a polyamic acid obtained by polymerizing a tetracarboxylic dianhydride represented by the above formula (1) to a diamine component to carry out hydrazine imidization. Solvent. 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 crystal in a specific direction.

As described above, in the formula (1), W is a divalent group represented by the following formula. In the following formula, R ¹ is a hydrogen atom, -COOH, -N(CH ₂ CH=CH ₂ ) ₂ or -(CH ₂ ) _n1 CH ₃ , preferably a hydrogen atom, -COOH or -N(CH ₂ CH =CH ₂ ) ₂ . Further, the bonding position of R ¹ is not particularly limited, and is preferably an ortho or para position with respect to -NH- of the bonded benzene ring. N1 is an integer from 0 to 20. R ² is -C(=O)-, -SO ₂ -, -C(CH ₃ ) ₂ -, -O-, -CH ₂ -, -NH-, -C ₂ H ₄ -NH-CONH-C ₂ H ₄ - or -O(CH ₂ ) _m1 O-, preferably -SO ₂ -, -O-, -CH ₂ -, -NH- or -C ₂ H ₄ -NH-CONH-C ₂ H ₄ - . M1 is an integer from 1 to 5.

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

The tetracarboxylic dianhydride and the diamine component represented by the formula (1) are polymerized to obtain a polyamic acid, and the obtained polylysine is subjected to hydrazylation to obtain a polyimine. The polyimine thus obtained is a polyethylenimine which is dissolved in a solvent contained in the liquid crystal alignment agent of the present invention, that is, a solvent-soluble polyimine.

The liquid crystal alignment agent of the present invention contains a solvent-soluble polyimine and a solvent obtained by subjecting a polyamic acid obtained by polymerization of a tetracarboxylic dianhydride and a diamine component represented by the formula (1) to ruthenium imidization. . The solvent-soluble polyimine may be one type or two or more types. By using a solvent-soluble polyimine containing a tetracarboxylic dianhydride represented by the formula (1) as a raw material and a solvent as a liquid crystal alignment agent, as shown in the examples below, it is excellent in whitening and aggregation characteristics. In other words, when the liquid crystal alignment agent of the present invention is applied onto a substrate or the like, generation of agglomerates (whitening, aggregation) of a polymer (polyimine) at the end portion of the coating film surface can be suppressed, and thus a uniform coating film can be obtained. . Therefore, even after being applied to a substrate or the like for a long period of time, a liquid crystal alignment film having excellent uniformity can be produced. As described above, by solvent-soluble polyimine containing a tetracarboxylic dianhydride represented by the formula (1) as a raw material and a solvent The liquid crystal alignment agent is less likely to be whitened or aggregated, and the reason why the uniformity of the coating film is high is not known. However, it is presumed that the starting material is a guanamine bonded to a specific structure of the tetracarboxylic dianhydride represented by the formula (1). The influence of the bond is good, and the compatibility with the solvent is better. Further, the solvent-soluble polyimine which is a raw material of the tetracarboxylic dianhydride represented by the formula (1) is dissolved in a solvent used for a liquid crystal alignment agent such as N-methyl-2-pyrrolidone or 2-butoxyethanol. High in nature, the liquid crystal alignment agent will not precipitate for a long time, and the preservation stability is high.

Further, the method for producing the tetracarboxylic dianhydride represented by the formula (1) is not particularly limited, and for example, 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride 4-chloro and H ₂ NW-NH can be used. ₂ (W is the same as W in the formula (1)) and is produced by a reaction. Specifically, for example, there is a production method described in JP-A-2012-72121. Further, for example, when a tetracarboxylic dianhydride represented by the formula (1) wherein R ² is -C ₂ H ₄ -NH-CONH-C ₂ H ₄ - is produced, for example, 1,2,4-cyclohexane can be used. The alkanetricarboxylic acid-1,2-anhydride 4-chloro is produced by reacting with the diamine described in the specification of WO2010/053128.

Further, the tetracarboxylic dianhydride represented by the formula (1) and the tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the formula (1) (hereinafter also referred to as other tetracarboxylic dianhydride) may be used together with the diamine. Ingredients reaction. In this case, the tetracarboxylic dianhydride represented by the formula (1) is preferably a total amount of 60 to 95 mol% of the tetracarboxylic dianhydride component for the synthesis using polyglycine (particularly solvent-soluble polyimine). More preferably, the amount of 70 to 90 mol% of the tetracarboxylic dianhydride component is tetracarboxylic dianhydride represented by the formula (1). The tetracarboxylic dianhydride represented by the formula (1) together with the other tetracarboxylic dianhydride is a tetracarboxylic dianhydride component.

The other tetracarboxylic dianhydride is represented, for example, by the following formula (2) Tetracarboxylic dianhydride.

(In the formula (2), Z ₁ is a tetravalent organic group having 4 to 13 carbon atoms of 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 each of them may be the same or different. In the formula (2g), Z ₆ and Z ₇ are a hydrogen atom or a methyl group. Each can be the same or different).

In the formula (2), a particularly preferable structure of Z ₁ is, for example, from the viewpoints of polymerization reactivity or ease of synthesis, for example, formula (2a), formula (2c), formula (2d), formula (2e), and formula (2). 2f) or formula (2g). Among them, preferred are the formula (2a), the formula (2e), the formula (2f) or the formula (2g).

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

Other tetracarboxylic dianhydrides other than the tetracarboxylic dianhydride represented by the above formula (2), for example, pyromellitic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6 -naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7-nonanetetracarboxylic acid, 1,2,5,6-nonanetetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, bis(3,4-dicarboxyphenyl)ether, 3,3',4,4'- Benzophenone tetracarboxylic 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-bis(3,4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)dimethyl decane, double (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-decanetetracarboxylic acid or 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid anhydride.

Further, as a raw material of the solvent-soluble polyimine, the tetracarboxylic dianhydride represented by the above formula (1) or another tetracarboxylic dianhydride is used. Each of them may be one type or two or more types.

The diamine component to be reacted with the tetracarboxylic dianhydride component such as the tetracarboxylic dianhydride represented by the formula (1) is not particularly limited, and a diamine generally used for a liquid crystal alignment agent can be used. Typical diamines include, for example, a diamine, a diamine having a side chain in which a liquid crystal is vertically aligned, a diamine which exhibits a high pretilt angle of a liquid crystal, and a diamine having a photoreactive group.

Commonly used diamines are, 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-diaminoisoxoxoyl, 4,4'-diamino Biphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-di Hydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-biphenyl, 3, 3'-Trifluoromethyl-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diamine linkage Benzene, 2,3'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenyl Methane, 2,2'-diaminodiphenylmethane, 2,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodi Phenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 2,3'-di Diphenyl ether, 4,4'-sulfonyldiphenylamine, 3,3'-sulfonyldiphenylamine, bis(4-aminophenyl)decane, bis(3-aminophenyl)decane, Dimethyl-bis(4-aminophenyl)decane, dimethyl-bis(3-aminophenyl)decane, 4,4'-thiodiphenylamine, 3,3'-thiodiphenylamine, 4, 4'-Diaminodiphenylamine, 3,3'-diaminodiphenyl Amine, 3,4'-diaminodiphenylamine, 2,2'-diaminodiphenylamine, 2,3'-diaminodiphenylamine, 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- Diaminonaphthalene, 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-double ( 4-aminophenyl)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,4-double (4-Aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4- Aminophenyl)benzene, 1,4-bis(4-amine Benzyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-[1,4-phenylenebis(methylene)]diphenylamine, 4,4'-[ 1,3-phenylphenylbis(methylene)]diphenylamine, 3,4'-[1,4-phenylenebis(methylene)]diphenylamine, 3,4'-[1,3- Phenyl bis(methylene)]diphenylamine, 3,3'-[1,4-phenylenebis(methylene)]diphenylamine, 3,3'-[1,3-phenylene double (methylene)]diphenylamine, 1,4-phenylene bis[(4-aminophenyl)methanone], 1,4-phenylphenylbis[(3-aminophenyl)methanone] , 1,3-phenylene bis[(4-aminophenyl)methanone], 1,3-phenylene bis[(3-aminophenyl)methanone], 1,4-phenylene Bis(4-aminobenzoic acid ester), 1,4-phenylene bis(3-aminobenzoate), 1,3-phenylene double (4-Aminobenzoic acid ester), 1,3-phenylphenylbis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, double (3- Aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, N,N'-( 1,4-phenylene) bis(4-aminophenylguanamine), N,N'-(1,3-phenylene)bis(4-aminophenylguanamine), N,N'-( 1,4-phenylene) bis(3-aminophenylguanamine), N,N'-(1,3-phenylene)bis(3-aminophenylguanamine), N,N'-double (4-Aminophenyl)terephthalamide, N,N'-bis(3-aminophenyl)terephthalamide, N,N'-bis(4-aminophenyl) M-xylguanamine, N,N'-bis(3-aminophenyl)m-xylyleneamine, 9,10-bis(4-aminophenyl)anthracene, 4,4'-double ( 4-aminophenoxy)diphenylanthracene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-amino group Phenoxy)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 group- 4-methylphenyl)propane, 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, 1,3-bis(4-aminophenoxy)propane, 1,3-double (3-Aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,4-bis(3-aminophenoxy)butane, 1,5-double (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-aminophenoxyl) Base) decane, 1,10-(4-aminophenoxy)decane, 1,10-(3-aminophenoxy)decane, 1,11-(4-aminophenoxy) Undecane, 1,11-(3-aminophenoxy)undecane, 1,12-(4-aminophenoxy)dodecane, 1,12-(3-aminophenoxyl An aromatic diamine such as dodecane, an alicyclic diamine such as bis(4-aminocyclohexyl)methane or bis(4-amino-3-methylcyclohexyl)methane, or a 1,3-di Aminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diamine Aliphatic two of octane, 1,9-diaminodecane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, etc. amine.

The general-purpose diamine is preferably used in an amount of from 50 to 95 mol% of the diamine component for the synthesis of polylysine (particularly solvent-soluble polyimine), more preferably 70% of the diamine component. 90% by mole.

a diamine having a side chain which vertically aligns a liquid crystal or a diamine which exhibits a high pretilt angle of a liquid crystal, for example, a group having a long-chain alkyl group, a long-chain alkyl group having a ring structure or a branched structure, a cholesteryl group or A group in which one or all of the hydrogen atoms of the groups are substituted with a group of a fluorine atom as a side chain diamine. Specifically, for example, there are diamines represented by the following formulas (3), (4), (5), and (6), but are not limited thereto.

(In the formula (3), each of l, m and n is an integer representing 0 or 1 independently, and R ³ is an alkylene group having 2 to 6 carbon atoms, -O-, -COO-, -OCO-, - NHCO-, -CONH-, or a C1-C 3 alkyl-ether group, R ⁴ , R ⁵ and R ⁶ each independently represent a phenyl or cycloalkyl group, and R ⁷ represents a hydrogen atom, An alkyl group having 2 to 24 carbon atoms or a fluorine-containing alkyl group, a monovalent aromatic ring, a monovalent aliphatic ring, a monovalent heterocyclic ring, or a one-valent large cyclic substituent formed by the same.

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

From the viewpoints of easiness of synthesis and ability to vertically align liquid crystals, R ⁴ , R ⁵ and R ⁶ in the formula (3) are preferably 1, m, n, R ⁴ and R ⁵ shown in Table 1 below. A combination of 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 a carbon number. 2~12 alkyl or fluoroalkyl. 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 monovalent large cyclic substituent is more preferably an alkyl group having 12 to 20 carbon atoms or a fluorine-containing alkyl group.

The ability of a polymer having a side chain for vertically aligning the liquid crystal to vertically align the liquid crystal differs depending on the structure of the side chain in which the liquid crystal is vertically aligned. Generally, when the amount of the side chain in which the liquid crystal is vertically aligned is increased, that is, the diamine When the content of the diamine having a side chain in which the liquid crystal is vertically aligned is increased in the composition, the ability to vertically align the liquid crystal is increased, and when it is small, the ability is lowered. Further, when it has a ring structure, the ability to vertically align the liquid crystal tends to be higher than that of the case where the ring structure is not formed.

(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 , l, m, and n are the same as defined in the above formula (3), and a' represents a divalent group having a structure in which one element such as hydrogen is removed in 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, and A ₁₅ is a 1,4-cyclohexylene group or a 1,4-phenylene group, A ₁₆ Is an oxygen atom or -COO-* (but with a "*" linkage and A ₁₅ linkage), A ₁₇ is an oxygen atom or -COO-* (but with a "*" linkage and (CH ₂ )a ₂ Bonding. Further, 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 particularly limited. Specifically, when it is relative to a side chain (-R ³ -(R ⁴ ) _l -(R ⁵ ) _m -(R ⁶ ) _n -R ⁷ ), for example, there are 2, 3 positions on the benzene ring, 2, 4 Position, 2, 5 position, 2, 6 position, 3, 4 position, 3, 5 position. Among them, from the viewpoint of reactivity in synthesizing polyamic acid, it is preferably 2, 4 position, 2, 5 position, and 3, 5 position. When considering the easiness in synthesizing a diamine, it is more preferably a 2, 4 position or a 3, 5 position.

The specific structure of the formula (3) is, for example, a 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 [A-5], 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-, A ₃ -based 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 fluoro group, a cyano group, a trifluoromethyl group, a nitro group, an azo group, a methyl group, an ethyl group, Ethyloxy 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 isomers of 1,4-cyclohexylene are each inverted. Isomer).

(In the formula [A-15] and the formula [A-16], A ₉ is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexene are each trans-form Structure).

Specific examples of the diamine represented by the formula (4) include, for example, the diamine represented by the following formula [A-25] to the formula [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 - The NH-, A ₁₃ series 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, from the viewpoints of the ability to vertically align the liquid crystal and the response speed of the liquid crystal, [A-1], [A-2], [A-3], [A-4], [A-5], [A-25], [A-26], [A-27], [A-28], [A-29], [A-30] diamine.

The diamine having a side chain which vertically aligns the liquid crystal or the diamine which exhibits a high pretilt angle of the liquid crystal is preferably a diamine component for synthesizing polyphosphamide (particularly solvent-soluble polyimine). The amount of 0 to 50 mol% is more preferably 10 to 40 mol% of the diamine component.

The diamine having a photoreactive group has a vinyl group, an acrylonitrile group, a methacryloyl group, an allyl group, a styryl group, a cinnamyl group, a Chalconyl Groups, a coumarin group, The diamine which is a side chain of a photoreactive group such as a maleimine group, for example, has a diamine represented by the following general formula (7), but is not limited thereto.

(R ⁸ in the formula (7) represents a single bond or -CH ₂ -, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH ₂ O-, - Any of N(CH ₃ )-, -CON(CH ₃ )-, -N(CH ₃ )CO-, R ⁹ represents a single bond or an alkylene group having 1 to 20 carbon atoms which are unsubstituted or substituted by a fluorine atom. The alkyl group -CH ₂ - may be optionally substituted by -CF ₂ - or -CH=CH-, and any of the following groups may be substituted by such groups when they are not adjacent to each other; -O- , -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a divalent carbocyclic ring, a divalent heterocyclic ring. R ¹⁰ represents a vinyl group, an acrylonitrile group, a methacryl fluorenyl group, an allylic group A group, a 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, in place of the carbon ring or the hetero ring of the divalent carbocyclic ring or the divalent heterocyclic ring of any of -CH ₂ -, which is, for example, R ⁹ is specifically substituted, for example, the following structures are 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 structure represented by the following formula from the viewpoint of photoreactivity.

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

The bonding position of the two amine groups (-NH ₂ ) in the formula (7) is not particularly limited. Specifically, with respect to the side chain (-R ⁸ -R ⁹ -R ¹⁰ ), for example, there are 2, 3 positions, 2, 4 positions, 2, 5 positions, 2, 6 positions, 3, 4 on the benzene ring. Location, 3, 5 position. Among them, from the viewpoint of reactivity in synthesizing polyamic acid, it is preferably 2, 4 position, 2, 5 position or 3, 5 position. When considering the easiness in synthesizing a diamine, it is more preferably a 2, 4 position or a 3, 5 position.

The diamine having a photoreactive group is specifically, for example, the following compounds, but is not limited thereto.

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

Further, such a photoreactive group-containing diamine is preferably used in an amount of from 0 to 70 mol% of the diamine component for synthesizing polyglycine (particularly solvent-soluble polyimine). It is 0~60% by mole.

When the diamine is used as a liquid crystal alignment film, the liquid crystal alignment property, the pretilt angle, the voltage holding property, the charge storage, and the response speed of the liquid crystal when the liquid crystal display element is used may be used in combination of one type or two types.

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 is a polylysine which is formed by dissolution. Specific examples are N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl alum, and four Methyl urea, pyridine, dimethyl hydrazine, γ-butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl decyl ketone, methyl ethyl ketone , methyl isoamyl ketone, methyl isopropyl ketone, cellosolve, ethyl stilbene, methyl sarbuta acetate, ethyl sarbuta 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 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 acetic acid Ester, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, dibutyl ether, diisobutyl Ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, lactic acid Ethyl ester, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate Ethyl ester, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, Diglyme or 4-hydroxy-4-methyl-2-pentanone and the like. These may be used alone or in combination. Further, even a solvent which does not dissolve polyamic acid may be used in combination with the above solvent as long as it does not precipitate the polyamic acid after the formation. Further, since the water in the organic solvent hinders the polymerization reaction and causes hydrolysis of the produced polylysine, it is preferred to use a dehydrated organic solvent.

When the diamine component and the tetracarboxylic dianhydride component are reacted in an organic solvent, any one of the following methods may be employed: a solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred, and the tetracarboxylic dianhydride component is directly added. Or a method of adding or dispersing or dissolving in an organic solvent; instead, for example, a method in which a diamine component is added to a solution in which a tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent, and a tetracarboxylic dianhydride is alternately added. a method of a component and a diamine component, etc. Diamine component or tetracarboxylic dianhydride component each using plural When the reaction is carried out, the reaction may be carried out in a state of being mixed beforehand, or may be separately reacted in sequence, and the low molecular weight bodies after the respective reactions may be subjected to a mixing reaction. The polymerization temperature at this time may be any temperature from -20 ° C to 150 ° C, preferably 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 polylysine (solvent-soluble polyimine). When the concentration is too high, the viscosity of the reaction liquid is too high and it is difficult to uniformly stir. Therefore, the concentration of the total amount of the diamine component and the tetracarboxylic dianhydride component in the reaction liquid is preferably from 1 to 50% by mass, more preferably from 5 to 30% by mass. The initial stage of the reaction can be carried out at a high concentration, and then an organic solvent is added.

In the polymerization reaction of polyamic acid, 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 resulting polyamine.

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

In the above formula [a], R ₁₁ and R ₁₂ each may be one type, and have the same repeating unit polymer, or R ₁₁ or R _{12 may} be plural, and polymers having repeating units having different structures may also be used. .

A solvent-soluble polyimine is obtained by dehydration ring closure of the polylysine.

The method for carrying out hydrazine imidization of poly-proline is, for example, a hydrazine imidization by heating a poly-proline solution directly, or imidization of a catalyst ruthenium in which a catalyst is added to a poly-proline solution.

The temperature at which the polyaminic acid is thermally imidated in the solution is from 100 ° C to 400 ° C, preferably from 120 ° C to 250 ° C, and the water formed by the hydrazine imidization reaction is excluded from the reaction system. The enthalpy imidization reaction is preferred.

The catalyst of the polyaminic acid oxime imidization is obtained 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. Chemical. The amount of the alkaline 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 of the amidate group, preferably 3 to 3 30 times Mo. The basic catalyst is, for example, pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is preferred because it has a moderate basicity required for carrying out the reaction. The acid anhydride is, for example, acetic anhydride, trimellitic anhydride or pyromellitic anhydride. When acetic anhydride is used, purification after the completion of the reaction is easy, which is preferable. Catenary imine The imidization rate can be controlled by adjusting the amount of the catalyst, the reaction temperature, and the reaction time.

When the resulting polymer (solvent-soluble polyimine or poly-proline) is recovered from a reaction solution of a polymer (solvent-soluble polyimine or poly-proline), the reaction solution is poured into a solvent to precipitate it. can. The solvent used for the precipitation is, for example, methanol, acetone, hexane, butyl sirolimus, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene or water. The polymer which is added to the solvent and precipitated is filtered and recovered, and then dried at normal temperature or under heat at normal pressure or reduced pressure. Further, the precipitate-recovered polymer is redissolved in an organic solvent, and the reprecipitation recovery operation is repeated 2 to 10 times to reduce impurities in the polymer. In this case, the solvent is, for example, an alcohol, a ketone or a hydrocarbon. When three or more solvents selected from the above are used, the purification efficiency can be further improved, which is preferable.

The dehydration ring closure ratio (the imidization ratio) of the proline acid group of the solvent-soluble polyimine contained in the liquid crystal alignment agent of the present invention does not necessarily need to be 100%, and may be 0% to 100% for the purpose of use or purpose. The range is preferably from 50% to 90%, more preferably from 82% to 86%.

When the molecular weight of the polymerized film or the solvent-soluble polyimine is considered, the strength of the obtained polymer film (liquid crystal alignment film), the workability at the time of formation of the polymer film, and the uniformity of the polymer film are considered as GPC (condensation). The weight average molecular weight measured by the gel permeation chromatography (Gel Permeation Chromatography) method is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000.

<solvent>

In addition, the solvent contained in the liquid crystal alignment agent of the present invention is not particularly limited as long as it dissolves the solvent-soluble polyimine, and examples thereof include N,N-dimethylformamide and N,N-dimethyl group. Acetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinylpyrrolidone, dimethyl hydrazine, tetramethyl 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, ethylene carbonate, propylene carbonate, diglyme, and 4-hydroxy-4-methyl-2-pentanone Etc. Organic solvents. These can be used alone 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 forming a uniform polymer film by coating. This content can be appropriately changed depending on the film thickness of the intended liquid crystal alignment film.

<Other components of liquid crystal alignment agent>

The polymer component contained in the liquid crystal alignment agent of the present invention may be a polylysine obtained by polymerizing a tetracarboxylic dianhydride and a diamine component represented by the above formula (1), and a solvent obtained by ruthenium imidization. a soluble polyimine, or a solvent-soluble polyimine obtained by polymerization of a polyamic acid obtained by polymerizing a tetracarboxylic dianhydride represented by the above formula (1) with a diamine component, and the like Polymer. At this time, it is obtained by polymerization of a tetracarboxylic dianhydride and a diamine component represented by the above formula (1). The polyaminic acid is a total amount of the solvent-soluble polyimine obtained by ruthenium imidization, and the content of the other polymer is from 0.5 to 90% by mass, preferably from 1.0 to 80% by mass. In addition to the polyamic acid obtained by polymerizing the tetracarboxylic dianhydride and the diamine component represented by the above formula (1), for example, the tetracarboxylic dianhydride represented by the above formula (1) is not contained. The polyamic acid or solvent-soluble polyimine obtained from the tetracarboxylic dianhydride component and the diamine component. Further, examples of the polymer other than the polyamine and the solvent-soluble polyimine include, for example, a polyphthalate, an acrylic polymer, a methacrylic polymer, polystyrene or polyamine.

The liquid crystal alignment agent of the present invention may contain an organic solvent (also referred to as a poor solvent) for improving the uniformity of the film thickness or the surface smoothness of the polymer film when the liquid crystal alignment agent is applied, within a range that does not impair the effects of the present invention. Poor solvent)) or compound. 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 poor solvent for improving the uniformity of the film thickness or the surface smoothness are isopropyl alcohol, methoxymethylpentanol, methyl stilbene, ethyl sirlox, butyl siroli, methyl race Lucas acetate, ethyl sirolimus acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene Alcohol 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 monoacetic acid Ester, 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 single ethyl Acid monopropyl ether, 3-methyl-3-methyl Oxybutyl 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, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate , n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3-methoxypropionic acid Ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-single Methyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, lactic acid An organic solvent having a low surface tension such as propyl ester, n-butyl lactate or isoamyl lactate.

These poor solvents can be used singly or in combination of plural kinds. When the poor 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.

Examples of the compound which improves the uniformity of the film thickness or the surface smoothness include a fluorine-based surfactant, a ruthenium-based surfactant, and a nonionic surfactant. More specifically, for example, EF TOP EF301, EF303, EF352 (manufactured by TOHKEM PRODUCTS), MAGAFAC F171, F173, R-30 (made by Dainippon Ink), FLORARD FC430, FC431 (manufactured by Sumitomo 3M), Asahiguard AG710, SURFLON S -382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass System), etc. The ratio of use 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.

A compound which improves the adhesion between the liquid crystal alignment film and the substrate, for example, contains a functional decane compound or contains an epoxy compound such as 3-aminopropyltrimethoxydecane or 3-aminopropyltriethoxy. Decane, 2-aminopropyltrimethoxydecane, 2-aminopropyltriethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-( 2-Aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-ureidopropyltrimethoxydecane, 3-ureidopropyltriethoxydecane, N-ethoxylate Carbonyl-3-aminopropyltrimethoxydecane, N-ethoxycarbonyl-3-aminopropyltriethoxydecane, N-triethoxydecylpropyltriethylamine, N -trimethoxydecylpropyltriethylethylamine, 10-trimethoxydecyl-1,4,7-triazadecane, 10-triethoxydecyl-1,4,7- Triazanonane, 9-trimethoxydecyl-3,6-diazadecyl acetate, 9-triethoxydecyl-3,6-diazaindolyl acetate, N -benzyl-3-aminopropyltrimethoxydecane, N-benzyl-3-aminopropyltriethoxydecane, N-phenyl-3-aminopropyltrimethoxysulfonium , N-phenyl-3-aminopropyltriethoxydecane, N-bis(oxyethylene)-3-aminopropyltrimethoxydecane, N-bis(ethylene oxide)-3- Aminopropyl triethoxy decane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl Alcohol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-double (N , N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and the like.

When the compound which is in contact with the substrate is used, it is preferably 0.1 to 30 parts by mass, more preferably 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 used is less than 0.1 part by mass, the effect of improving the adhesion 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 poor solvent and compound, the liquid crystal alignment agent of the present invention may be added with a dielectric material of interest for the purpose of changing the dielectric properties or electrical conductivity of the liquid crystal alignment film within the range not impairing the effects of the present invention. Or conductive material.

<Liquid alignment film ‧ Liquid crystal display element>

The liquid crystal alignment agent of the present invention is applied onto a substrate, and after firing, it is subjected to an alignment treatment by rubbing treatment or light irradiation, and can be used as a liquid crystal alignment film. When it is used for vertical alignment or the like, it can be used as a liquid crystal alignment film without alignment treatment. The substrate to be used at this time is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used as the glass substrate. Moreover, from the viewpoint of simplification of the process, 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 reflective liquid crystal display device, when only one side of the substrate is used, an opaque substrate such as a germanium wafer can be used. The electrode may also use a material that reflects light such as aluminum.

The coating method of the liquid crystal alignment agent is not particularly limited, but industrially, it is generally carried out by screen printing, lithography, letterpress printing, or inkjet method. Other coating methods include, for example, a dipping method, a roll coating method, a slit coating method, a spin coating method, or a spray coating method, and these methods can be used for the purpose. Since the liquid crystal alignment agent of the present invention is excellent in whitening and aggregation characteristics, there is almost no agglomerate of solvent-soluble polyimine which is likely to be generated at the end portion of the coating film surface formed by coating a liquid crystal alignment agent on a substrate. A liquid crystal alignment film excellent in uniformity or transparency can be produced.

The drying step after applying the liquid crystal alignment agent onto the substrate is not necessarily required, but the drying step is included when the time from the application to the time of baking is not required, or when the substrate is not baked immediately after coating. good. The drying means is not particularly limited as long as the shape of the coating film is not deformed by the substrate transfer or the like, and the solvent is removed. For example, a method of drying 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 form a liquid crystal alignment film (polymer film) by baking. In this case, the firing temperature may be any temperature of from 100 ° C to 350 ° C, preferably from 140 ° C to 300 ° C, more preferably from 150 ° C to 230 ° C, and still 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 generally known method such as a hot plate, a heat cycle oven or an IR (infrared) type oven, a belt conveyer furnace. Wait. When the thickness of the liquid crystal alignment film after firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered, preferably 5~ 300 nm, more preferably 10 to 100 nm. When the liquid crystal is aligned horizontally or obliquely, the liquid crystal alignment film after firing is rubbed or irradiated with polarized ultraviolet rays or the like.

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 obtain a liquid crystal display element. As an example, for example, a liquid crystal display element having a liquid crystal cell having two substrates disposed oppositely, a liquid crystal layer disposed between the substrates, and a liquid crystal layer disposed between the substrate and the liquid crystal layer, and the liquid crystal alignment of the present invention The above liquid crystal alignment film formed by the agent. The liquid crystal display element of the present invention has, for example, a twisted nematic (TN: Twisted Nematic) method, a vertical alignment (VA: Vertical Alignment) method, or an IPS (In-Plane Switching) method, and an OCB alignment (OCB: Optically Compensated Bend) and so on.

In the liquid crystal cell production method, for example, one of the liquid crystal alignment films is formed, and a spacer is dispersed on the liquid crystal alignment film of one of the substrates, and the liquid crystal alignment film surface is formed inside, and the other substrate is bonded to the substrate. The liquid crystal is injected under reduced pressure and sealed. Or a method in which a liquid crystal is dropped on a liquid crystal alignment film surface in which a spacer is spread, and the substrate is bonded and sealed.

Further, among the liquid crystal display elements in which the liquid crystal molecules vertically aligned with the substrate are subjected to an electric field response (vertical alignment method) When a PSA (Polymer Sustained Alignment) type liquid crystal display in which a photopolymerizable compound is added to a liquid crystal composition or an SC-PVA liquid crystal display to be added to a liquid crystal alignment film (liquid crystal alignment agent), the liquid crystal alignment film is formed. One of the pair of substrates is sealed with a liquid crystal or the like, and a voltage is applied to the liquid crystal alignment film and the liquid crystal, and ultraviolet rays are irradiated to polymerize the polymerizable compound.

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 may be used, and specifically, for example, MLC-2003, MLC-6608, MLC-6609 manufactured by Merck Co., Ltd., or the like.

As described above, the liquid crystal display element produced by using the liquid crystal alignment agent of the present invention has a uniform liquid crystal alignment film, and thus is excellent in reliability.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples. However, the invention is not limited to the embodiments.

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

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

APC16: 1,3-diamino-4-hexadecyloxybenzene

APC18: 1,3-diamino-4-octadecyloxybenzene

p-PDA: p-phenylenediamine

<organic solvent>

NMP: N-methyl-2-pyrrolidone

BCS: 2-butoxyethanol

The measurement method performed in the present example is shown below.

<Measurement of molecular weight>

The molecular weight of polyaminic acid and polyimine is determined by GPC (normal temperature gel permeation chromatography) device, and is converted into polyethylene glycol and polyethylene oxide. The number average molecular weight and the weight average molecular weight were calculated.

GPC device: manufactured by Shodex (GPC-101)

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

Column temperature: 50 ° C

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

Flow rate: 1.0ml/min

A standard sample for the calibration curve was prepared: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000, 30,000) manufactured by TOSOH Co., Ltd., and polyethylene glycol (molecular weight: about 12,000, 4,000, 1,000) manufactured by Polymer Laboratories.

<Measurement of sulfhydrylation rate>

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 measured for proton NMR at 500 MHz using a NMR measuring instrument (JNM-ECA500) manufactured by JEOL DATUM. The ruthenium imidization rate is determined by using a proton derived from a structure that has not changed before and after imidization as a reference proton, and the peak integral value of the proton is used and the NH group derived from proline is present in the vicinity of 9.5 to 10.0 ppm. The proton peak integral value 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 integral value of the peak of the reference proton, and α is the reference proton relative to the poly-proline (the imidization rate is 0%) The ratio of the number of NH protons of the proline.

(Synthesis Example 1)

PPHT (1.33 g) was used for the tetracarboxylic dianhydride component, and p-PDA (0.32 g) was used for the diamine component, and the reaction was carried out for 18 hours at room temperature in NMP (14.93 g) to obtain polylysine (PAA-1). The solid content is a solution having a concentration of 10% by weight.

(Synthesis Examples 2 to 8)

A solution of the polyaminic acid (PAA-2 to PAA-8) of Synthesis Examples 2 to 8 was obtained in the same manner as in the above Synthesis Example 1 except for the composition shown in Table 2.

(Synthesis Example 9)

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

(Synthesis Examples 10 to 16)

A powder of the polyimine (Synthesis of SPI-2 to SPI-8) of Synthesis Examples 10 to 16 was obtained in the same manner as in the above Synthesis Example 9 except for the composition shown in Table 3.

(Example 1)

NMP (7.53 g) was added to 0.50 g of the polymer (polyimine SPI-1) obtained in the above Synthesis Example 9, and the mixture was stirred at room temperature for 3 hours. At the end of the agitation, the polyimine was completely dissolved. Further, BCS (2.01 g) 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 5.0% by weight. This polymer solution directly becomes a shape A liquid crystal alignment agent for a liquid crystal alignment film.

(Examples 2 to 7 and Comparative Example 1)

The polymer solutions (A2 to A7) of Examples 2 to 7 and the polymer solution (B1) of Comparative Example 1 were obtained in the same manner as in Example 1 except for the compositions shown in Table 4. In any of Examples 2 to 7, as in Example 1, the polyimine was completely dissolved at the end of the stirring.

[Production of liquid crystal cell]

The polymer solution (A1) obtained in Example 1, that is, a liquid crystal alignment agent (A1), filtered using a 1.0 μm filter, 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 form a film. A coating film (polyimine film) having a thickness of 100 nm. The polyimine film was rubbed with a green cloth (roller diameter: 120 mm, number of revolutions: 1000 rpm, moving speed: 50 mm/sec, and the amount of impregnation was 0.3 mm), and then ultrasonically irradiated for 1 minute in pure water and dried at 80 ° C for 10 minutes. Forming a liquid crystal alignment film. Two substrates of the liquid crystal alignment film are prepared, and a spacer of 6 μm is disposed on the liquid crystal alignment film surface of one of the substrates, and then the rubbing directions of the two substrates are combined in an orthogonal manner to leave a liquid crystal injection port to surround the periphery. The film was sealed to prepare an empty cell having a cell gap of 6 μm. Liquid crystal (MLC-2003 (C080), manufactured by Merck Japan Co., Ltd.) was injected into the cell at room temperature under vacuum, and the injection port was closed to obtain a liquid crystal cell having a liquid crystal phase of 90 degree twist alignment.

Further, with respect to the liquid crystal alignment agents (A2 to A7) obtained in Examples 2 to 7 and the liquid crystal alignment agent (B1) obtained in Comparative Example 1, a liquid crystal cell was produced in the same manner as in the liquid crystal alignment agent (A1) obtained in Example 1. .

[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 the Mueller-Matrix method using "Axo Scan" manufactured by Axo Metrix. The results are shown in Table 5.

[Whitening ‧ evaluation of agglutination characteristics]

Each of the liquid crystal alignment agents (polymer solutions) obtained in Examples 1 to 7 and Comparative Example 1 was dropped on a Cr substrate by about 0.1 ml, and placed in an environment of a temperature of 23 ° C and a humidity of 55%. Near the end of the droplet, it was observed with a microscope every 10 minutes. The observation system uses a magnification of 100 times. When the time when the aggregates were generated was 10 minutes or less, the evaluation was ×, and if it was more than 10 minutes, the evaluation was Δ for less than 1 hour, the evaluation was ○ for 1 hour or longer, and the evaluation was ○ for 3 hours or longer. The evaluation results are shown in Table 5.

As shown in Table 5, the liquid crystal alignment agent (polymer solution) of Examples 1 to 7 containing the polyfluorene imine which is a raw material of the tetracarboxylic dianhydride represented by the formula (1) was evaluated in terms of whitening and agglutination characteristics. Even if no agglomerates were formed for 3 hours or more, it was found to have excellent whitening and agglutination properties. Further, in Comparative Example 1, aggregates were generated within 10 minutes, and whitening and aggregation characteristics were poor. Further, the liquid crystal alignment agents of Examples 1 to 7 were also confirmed to have a good alignment (pretilt angle) of the liquid crystal by the alignment treatment.

Claims (3)

A liquid crystal alignment agent comprising a solvent-soluble polyazide obtained by subjecting a polyamic acid obtained by polymerization of a tetracarboxylic dianhydride represented by the following formula (1) to a diamine component to carry out hydrazine imidization. Amines and solvents, (In the formula (1), W is a structure represented by the following formula) (wherein R ¹ is a hydrogen atom, -COOH, -N(CH ₂ CH=CH ₂ ) ₂ or -(CH ₂ ) _n1 CH ₃ , n1 is an integer from 0 to 20, and R ² is -C(= O)-, -SO ₂ -, -C(CH ₃ ) ₂ -, -O-, -CH ₂ -, -NH-, -C ₂ H ₄ -NH-CONH-C ₂ H ₄ - or -O ( CH ₂ ) _m1 O-, m1 is an integer from 1 to 5). A liquid crystal alignment film, the characteristics of which are used as claimed in the patent scope 1 item of liquid crystal alignment agent. A liquid crystal display element characterized by comprising a liquid crystal alignment film according to item 2 of the patent application.