TWI724089B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element using the same - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent, which can obtain a liquid crystal alignment film that does not impair the alignment of the liquid crystal and can maintain the voltage retention even after light irradiation.

The liquid crystal alignment agent of the present invention contains the following (A) component, (B) component, (C) component, and organic solvent, and (A) component: using a tetracarboxylic acid derivative component and containing a component selected from the following formula At least one diamine compound of a diamine compound having a structure of [A-1], a diamine compound having a structure of the following formula [A-2], and a diamine compound having a structure of the following formula [A-3] The polyimide precursor obtained from the diamine component of the compound and at least one polymer selected from the polyimide, component (B): selected from polyimide having a structural unit represented by the following formula (2) The amine precursor and the polyimide precursor are at least one type of polymer of the imidized polymer, component (C): a compound containing two or more crosslinkable functional groups.

(式中之符號的定義係如說明書中所記載)。

(The definition of the symbol in the formula is as described in the specification).

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element using the same

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

Liquid crystal display elements used in liquid crystal televisions, navigation, smart phones, etc. usually have a liquid crystal alignment film for controlling the arrangement of liquid crystals in the elements. The liquid crystal alignment film has the function of controlling the alignment of the liquid crystal molecules in a specific direction in a liquid crystal display element or a phase difference plate using a polymerizable liquid crystal. For example, a liquid crystal display element has a structure in which liquid crystal molecules constituting a liquid crystal layer are sandwiched by liquid crystal alignment films formed on the respective surfaces of a pair of substrates. Therefore, the liquid crystal molecules are aligned in a specific direction with the pretilt angle through the liquid crystal alignment film, and a response is generated by applying a voltage to the electrode provided between the substrate and the liquid crystal alignment film. As a result, the liquid crystal display element utilizes the alignment change caused by the response of the liquid crystal molecules to perform desired image display.

The liquid crystal alignment film has mainly used polyimide precursors such as polyamic acid or soluble polyimide A liquid crystal alignment agent whose main component is a solution of amine is coated on a glass substrate or the like, and the polyimide-based liquid crystal alignment film is fired.

With the high performance of liquid crystal display elements, in addition to exhibiting excellent liquid crystal alignment or a stable pretilt angle, the liquid crystal alignment film also requires a high voltage retention rate, less residual charge when a DC voltage is applied, and/or Due to the characteristics of rapid relaxation of the accumulated residual charge due to DC voltage, in recent years, materials with high voltage retention ratio have been particularly required for the power saving of liquid crystal display elements.

In order to meet the above requirements, there are various proposals. For example, in addition to polyamide acid or polyamide acid containing an imine group, a liquid crystal alignment agent containing a tertiary amine of a specific structure (for example, refer to Patent Document 1) or a liquid crystal alignment agent containing an isocyanate structure additive (for example, Refer to Patent Document 2) and so on.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-316200

[Patent Document 2] WO2014/178406 Publication

[Discovery of Invention]

With the high performance of liquid crystal display elements in recent years, the Flat and high-definition LCD TVs or in-vehicle applications such as car navigation systems and instrument panels use liquid crystal display elements. In this application, in order to obtain high brightness, a backlight with a large amount of heat may be used. Therefore, the liquid crystal alignment film needs high stability against the light from the backlight. In particular, when the voltage retention rate, which is one of the electrical characteristics of the liquid crystal display element, is reduced by the light from the backlight, the residual image defect (also called line afterimage), which is one of the display defects of the liquid crystal display element, is prone to occur and cannot be obtained. Highly reliable liquid crystal display element.

Therefore, in addition to good initial characteristics of the liquid crystal alignment film, for example, it is also required that the voltage retention rate is not easily reduced even after long-term light irradiation. In addition, in order to reduce power consumption, low-frequency driving is gradually required, and an alignment film with high voltage holding capability is further required.

When using a liquid crystal alignment agent in which various crosslinking agents are added to polyamic acid, although a liquid crystal display element with excellent voltage retention characteristics can be obtained, the liquid crystal alignment may be impaired in some cases. In addition, the effect of the crosslinking agent cannot be fully exhibited due to the combination with the polymer species contained in the liquid crystal alignment agent, and the voltage retention may be insufficient.

The inventors of the present invention completed the present invention as a result of careful examination in order to solve the above-mentioned problems. That is, the technical features of the present invention are as follows.

A liquid crystal alignment agent containing the following (A) component, (B) component, (C) component, and organic solvent.

(R¹及R²各自獨立為氫原子、碳數1~4之烷基或下述式(1)表示之基，其至少一方係藉由熱而取代成氫原子之保護基的熱脫離性基，R₃、R₄、及R₅各自獨立為氫原子或可具有取代基之碳數1~20之一價烴基，D係藉由熱而取代成氫原子之保護基的熱脫離性基。) (A) Component: use a tetracarboxylic acid derivative component and a diamine compound containing a structure selected from the following formula [A-1], a diamine compound having a structure of the following formula [A-2], and The polyimide precursor obtained by the diamine component of at least one diamine compound of the diamine compound of the structure of the following formula [A-3] and at least one polymer selected from the polyimine,

(R ¹ and R ² are each independently a hydrogen atom, an alkyl group with 1 to 4 carbon atoms, or a group represented by the following formula (1), at least one of which is a protective group that is substituted by heat to a hydrogen atom. R ₃ , R ₄ , and R ₅ are each independently a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms that may have a substituent, and D is a thermally desorbable group that is substituted into a protective group for a hydrogen atom by heat .)

(X₁為下述式(X-1)表示之4價之有機基，Y₁係2價有機基，R₁係氫原子、或碳數1~5之烷基，A₁~A₂各自獨立 為氫原子、或可具有取代基之碳數1~10之烷基、碳數2~10之烯基、或碳數2~10之炔基) (B) Component: at least one polymer selected from the group of polyimide precursors having the structural unit represented by the following formula (2) and the imidized polymers of the polyimide precursor ,

(X ₁ is a tetravalent organic group represented by the following formula (X-1), Y ₁ is a divalent organic group, R ₁ is a hydrogen atom, or an alkyl group with 1 to 5 carbon atoms, each of _{A 1} ~A ₂ Independently a hydrogen atom, or an alkyl group with 1 to 10 carbons, an alkenyl group with 2 to 10 carbons, or an alkynyl group with 2 to 10 carbons that may have substituents)

(C) Component: A compound containing two or more crosslinkable functional groups.

According to the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment film that does not impair the alignment of the liquid crystal over a long period of time, and particularly maintains the voltage retention rate even after light irradiation. Thereby, the liquid crystal display element having the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can provide excellent displays used in liquid crystal televisions, smart phones, car navigation, etc.

[The form of implementing the invention] <(A) Ingredient>

The component (A) contained in the liquid crystal alignment agent of the present invention is composed of a tetracarboxylic acid derivative component and a diamine compound containing a structure selected from the following formula [A-1], having the following formula [A-2 The polyimide precursor and the polyimide obtained from the diamine component of at least one diamine compound of the diamine compound having the structure of the following formula [A-3] and the diamine compound having the structure of the following formula [A-3] are selected At least one type of polymer (hereinafter also referred to as a specific polymer (A)).

In the formula [A-1], R ¹ , R ² , and A are as defined above. Among them, ^{at least one or both of R 1} and R ² are thermally desorbable groups that are substituted into a protective group of a hydrogen atom by heat. From the viewpoint of the strength of the alignment film during rubbing, it is particularly ^{preferable that only one of R 1} and R ² is a heat-releasable group.

From the standpoint of the storage stability of the liquid crystal alignment agent, the thermally detachable group is preferably one that does not detach at room temperature, preferably at 80°C or higher, and more preferably is a protecting group that is detached by heat at 100°C or higher. The thermally-detachable group is preferably a group represented by the following formula (1), or a 9-phosphonium methoxycarbonyl group.

In the formula (1), A is a single bond or a hydrocarbon group with 1 to 4 carbon atoms, preferably a divalent group formed by an alkylene group. From the standpoint of the temperature of the desorption, the tertiary butoxycarbonyl group is preferred.

Preferred examples of diamines having a structure represented by the above formula [A-1] in the molecule include diamines represented by the following formula [A-1-1].

In the above formula [A-1-1], R ¹ and R ² also include their preferred ones, which is the same as in the case of the formula [A-1]. The two n's are each independently an integer of 0-3, and the ease of obtaining from raw materials is preferably 0 or 1, and more preferably 1.

In addition, in formula [A-1-1], the amine group (-NH ₂ ) in each benzene ring is relative to the bonding position of the alkylene ring, which can be any position of ortho, meta, or pair, but From the viewpoint of ease of synthesis and polymerization reactivity, meta-position or para-position is preferable, and para-position is more preferable.

Preferred examples of the diamine represented by the formula [A-1-1] include the following compounds.

In formula [A-2], R ₃ and R ₄ are each independently a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms that may have a substituent. Especially in the case of bulky substituents, the liquid crystal alignment may be lowered. Therefore, a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or a phenyl group is preferable, and a hydrogen atom or a methyl group is particularly preferable.

D is a thermally desorbable group that is substituted into a protective group of a hydrogen atom by heat, and this preferred aspect is also included, as defined in the above formula [A-2]. Particularly preferred is the tertiary butoxycarbonyl group.

The diamine having the structure represented by the above formula [A-2] is preferably represented by the following formula [A-2-1].

Among them, in the case represented by the following formula [A-2-2], the liquid crystal alignment of the obtained liquid crystal alignment film becomes high, which is particularly preferred.

A ¹ and A ⁵ are each independently a single bond or an alkylene group having 1 to 5 carbon atoms. From the viewpoint of the reactivity with the functional group in the sealant, a single bond or a methylene group is preferred. A ² and A ⁴ are alkylene groups having 1 to 5 carbon atoms, preferably methylene or vinyl groups.

A ³ is an alkylene group having 1 to 6 carbon atoms or a cyclic alkylene group. From the viewpoint of the reactivity with the functional group in the sealant, a methylene group or a vinyl group is preferred.

B ¹ and B ² are each independently a single bond, -O-, -NH-, -NMe-, -C(=O)-, -C(=O)O-, -C(=O)NH-,- C(=O)NMe-, -OC(=O)-, -NHC(=O)-, or, -N(Me)C(=O)-. From the viewpoint of the liquid crystal alignment of the obtained liquid crystal alignment film, a single bond or -O- is preferred.

D ₁ is a tertiary butoxycarbonyl group or a 9-stilbene methoxycarbonyl group. From the viewpoint of the temperature of deprotection, the tertiary butoxycarbonyl group is preferred. a is 0 or 1.

Specific examples of the diamine represented by the formula (A-2-2) include the following formulas (2-1) to (2-21).

In formulas (2-1) to (2-21), Me represents a methyl group, and D ₂ represents a tertiary butoxycarbonyl group.

Among them, formulas (2-1) to (2-4) are more preferred, and formula (2-1) is particularly preferred.

Among the diamines having a structure represented by the above formula [A-3], those represented by the following formula [A-3-1] or the following formula [A-3-2] are preferred.

Among them, represented by the following formula [A-3-3] and the following formula [A-3-4] In this case, the liquid crystal alignment of the obtained liquid crystal alignment film becomes higher, so it is particularly good.

In formula [A-3-1] and formula [A-3-3], A ¹ , A ⁵ , B ¹ , and B ² also include preferable examples, which are similar to A described in formula [A-2-1] ¹ , A ⁵ , B ¹ , and B ^{2 have the} same definition. R _{5 is} each independently a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms that may have a substituent. From the viewpoint of liquid crystal alignment, R _{5 is} preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom.

A ⁶ is a single bond or an alkylene group with 1 to 6 carbon atoms. From the viewpoint of liquid crystal alignment, a single bond, a methylene group, a vinyl group, or a propenyl group is preferred, and a single bond or a methylene group is more preferred.

D ₁ is a tertiary butoxycarbonyl group or a 9-tanoylmethoxycarbonyl group, and from the viewpoint of the temperature of deprotection, the tertiary butoxycarbonyl group is preferred. a is 0 or 1.

In formula [A-3-2] and formula [A-3-4], ^{preferred examples of A 6} , R ₅ , and D ₁ ^{are also the same as A 6} , R described in formula [A-2-1] _5, the same definition and D _1.

Specific examples include the following formulas (3-1) to (3-5).

In formulas (3-1) to (3-5), D ₂ represents a tertiary butoxycarbonyl group.

Among them, formula (3-1) to formula (3-4) are more preferred, and formula (3-1) is particularly preferred.

At least 1 selected from diamines having the structure represented by the above formula [A-1], diamines having the structure represented by the above formula [A-2], and diamines having the structure represented by the above formula [A-3] The content of this diamine is relative to the polyimide precursor used in the component (A) contained in the liquid crystal alignment agent of the present invention and the polyimide precursor used in the production of the imidized polymer The total diamine component is preferably 5 to 80 mol%, more preferably 10 to 50 mol%.

The diamine component used for the component (A) contained in the liquid crystal alignment agent of the present invention can be selected from the diamines having the structure represented by the above-mentioned formulas [A-1], [A-2] and [A-3] At least one diamine and other diamines.

The above-mentioned other diamines include 2,4-dimethyl-m-phenylenediamine, 2,6-diaminotoluene, m-phenylenediamine, p-phenylenediamine, 4,4'-diamine Biphenyl, 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'-biphenyl, 3,3'-trifluoromethyl-4,4'-diaminobiphenyl, 3, 4'-diamino biphenyl, 3,3'-diamino biphenyl, 2,2'-diamino biphenyl, 2,3'-diamino biphenyl, 4,4'-diamino biphenyl Diphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminodiphenylmethane, 2,3'-di Amino diphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-diamine Diphenyl ether, 2,3'-diaminodiphenyl ether, 4,4'-sulfonyl diphenylamine, 3,3'-sulfonyl diphenylamine, bis(4-aminophenyl) silane, Bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4'-thiobisaniline, 3,3'-thiodiphenylamine, 4,4'-diaminodiphenylamine, 3,3'-diaminodiphenylamine, 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 Naphthalene, 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-bis(4-aminophenyl)butane, 1,4-bis(3-amine Phenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4- Amino Phenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene , 1,3-bis(4-aminophenoxy)benzene, 4,4'-[1,4-phenylene bis(methylene)]diphenylamine, 4,4'-[1,3- Phenylenebis(methylene)]diphenylamine, 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) ketone], 1,4-phenylene bis[(3-aminophenyl) ketone], 1,3 -Phenylene bis[(4-aminophenyl) ketone], 1,3-phenylene bis[(3-aminophenyl) ketone], 1,4-phenylene bis(4- Amino benzoate), 1,4-phenylene bis (3-amino benzoate), 1,3-phenylene bis (4-amino benzoate), 1,3- Phenylene bis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4 -Aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, N,N'-(1,4-phenylene)bis(4-aminobenzene) Formamide), N,N'-(1,3-phenylene)bis(4-aminobenzamide), N,N'-(1,4-phenylene)bis(3-amine) Benzamide), N,N'-(1,3-phenylene) bis(3-aminobenzamide), N,N'-bis(4-aminophenyl)p-phenylene Formamide, N,N'-bis(3-aminophenyl)p-xylylenedimethamide, N,N'-bis(4-aminophenyl)m-xylylenedimethamide, N,N' -Bis(3-aminophenyl) metaxylamide, 9,10-bis(4-aminophenyl)anthracene, 4,4'-bis(4-aminophenoxy)diphenyl Supplement, 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)hexafluoro Propane, 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, 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)nonane, 1,9- Bis(3-aminophenoxy)nonane, 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-aminophenoxy)dodecane, bis(4-aminocyclohexyl)methane, 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-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane or 1,12-diaminododecane, and these amine groups are level 2 Amino-based diamine.

The other diamine compound used in the component (A) contained in the liquid crystal alignment agent of the present invention is based on the solubility of the component (A) in solvents or the coating properties of the liquid crystal alignment agent, and the alignment of the liquid crystal when used as a liquid crystal alignment film For characteristics such as performance, voltage retention, and accumulated charge, one or two or more of them can be used.

<Tetracarboxylic acid derivative component>

The tetracarboxylic acid derivative component used to manufacture the component (A) contained in the liquid crystal alignment agent of the present invention is not only tetracarboxylic dianhydride, but also tetracarboxylic acid and tetracarboxylic acid dihalogenation of its tetracarboxylic acid derivatives. Compounds, dialkyl tetracarboxylic acid or dialkyl tetracarboxylic acid dihalide. Among them, it is preferable to use at least one dialkyl tetracarboxylic acid selected from the tetracarboxylic dianhydride represented by the following formula [4] and derivatives thereof. The tetracarboxylic dianhydride and its derivatives represented by the following formula [4] are collectively referred to as a specific tetracarboxylic acid component.

In the formula (4), Z represents a structure selected from at least one type selected from the group consisting of the following formulas [4a] to [4q].

Z ¹ to Z ⁴ each independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, or a benzene ring. Z ⁵ and Z ⁶ each independently represent a hydrogen atom or a methyl group.

From the viewpoint of the ease of synthesis or the ease of polymerization reactivity during the production of the polymer, Z is preferably formula [4a], formula [4c] ~ formula [4g], formula [4k] ~ formula [4m] or formula [4p]. More preferably, it is formula [4a], formula [4e]-formula [4g], formula [4l], formula [4m] or formula [4p]. Particularly preferred are [4a], formula [4e], formula [4f], formula [4l], formula [4m] or formula [4p].

In addition, specifically, the following formula [4a-1] or formula [4a-2] is preferable.

(A) The specific tetracarboxylic acid component in component, in all four Among 100 mole% of the carboxylic acid derivative component, it is preferably 50-100 mole%, more preferably 70-100 mole%, and particularly preferably 80-100 mole%.

The specific tetracarboxylic acid component is based on the solubility of the specific polymer (A) in the solvent, the coating property of the liquid crystal alignment agent, the liquid crystal alignment when used as a liquid crystal alignment film, the voltage retention rate, and the accumulated charge. It can be used 1 Type or more than 2 types.

In the polyimide-based polymer of the specific polymer (A), other tetracarboxylic acid components other than the specific tetracarboxylic acid component may also be used.

Other tetracarboxylic acid components include tetracarboxylic acid, tetracarboxylic dianhydride, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide shown below.

Other tetracarboxylic acid components include 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,5,6-anthracenetetracarboxylic 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) sulfide, bis(3,4-dicarboxyphenyl)methane, 2,2-bis(3,4-dicarboxyl) Phenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis(3,4-dicarboxyphenyl)propane, bis(3,4-dicarboxyphenyl)dimethyl Silane, bis(3,4-dicarboxyphenyl)diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6-bis(3,4-dicarboxyphenyl)pyridine, 3 ,3',4,4'-diphenyl tetracarboxylic acid, 3,4,9,10-perylene tetracarboxylic acid or 1,3-diphenyl-1,2,3,4-cyclobutane tetracarboxylic acid Carboxylic acid and so on.

The above-mentioned other tetracarboxylic acid components are based on the solubility of the specific polymer (A) in solvents or the coating properties of the liquid crystal alignment agent, the liquid crystal alignment when used as a liquid crystal alignment film, the voltage retention rate, and the characteristics of the accumulated charge. It can also be used in one type or in a mixture of two or more types.

<(B) Ingredient>

The component (B) contained in the liquid crystal alignment agent of the present invention is selected from the polyimide precursor having the structural unit represented by the following formula (2) and the imidized polymer of the polyimide precursor At least one type of polymer in the group (hereinafter also referred to as a specific polymer (B)).

In formula (2), X ₁ , Y ₁ , R ₁ , and A ₁ to A ₂ are as defined above. Among them, R _{1 is} preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom. A ₁ to A _{2 are} preferably hydrogen atoms or methyl groups.

Specific examples of the above-mentioned alkyl group in R ₁ include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl Base and so on. From the viewpoint of easy imidization by heating, R _{1 is} preferably a hydrogen atom or a methyl group.

The preferable content ratio of the structural unit of (2) above is 5 to 90 mol% in the same polymer, more preferably 10 to 90 mol%, and still more preferably 10 to 80 mol%.

In addition, the polymer of the component (B) may have a structural unit represented by the following formula (3) in addition to the structural unit represented by the above formula (2).

The component (B) of the present invention may be a polymer having a structural unit represented by the formula (2) and a structural unit of the formula (3), or a polymer having a structural unit represented by the formula (2) and a polymer with the structural unit represented by the formula (3). ) Is a mixture of structural units of polymers, but the former is preferred. (B) The content ratio of the structural unit of formula (3) contained in the polymer of the component is 5 to 90 mol% in the polymer, preferably 10 to 90 mol%, and more preferably 20 to 90 mol%.

In the above formula (3), X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. X ₂ may be a mixture of two or more types. When a _{specific example of X 2} is shown, the following formulas (X-2) to (X-44) can be cited.

In the above formula (X-2), R ₈ to R ₁₁ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbons, an alkenyl group having 2 to 6 carbons, an alkynyl group, or a phenyl group. When R ₈ to R _{11 have} a bulky structure, the alignment of the liquid crystal may be reduced. Therefore, a hydrogen atom, a methyl group or an ethyl group is preferable, and a hydrogen atom or a methyl group is particularly preferable.

In formula (3), the availability of X ₂ from a monomer preferably contains a structure selected from (X-2) to (X-14).

To further improve the reliability of the obtained liquid crystal alignment film, X _{2 is} preferably a structure formed only by aliphatic groups such as (X-2)~(X-7) and (X-10), more preferably (X -2). In addition, in order to exhibit good liquid crystal alignment, X ₂ is more preferably the following formula (X2-1) or (X2-2).

In the above formula (2) and formula (3), A ₁ and A ₂ are each independently a hydrogen atom, or an alkyl group with 1 to 10 carbon atoms that may have a substituent, and an alkene with 2 to 10 carbon atoms that may have a substituent Group, optionally substituted alkynyl group with 2 to 10 carbons.

Specific examples of the aforementioned alkyl group include methyl, ethyl, propyl, butyl, t-butyl, hexyl, octyl, decyl, cyclopentyl, cyclohexyl, and dicyclohexyl. Examples of the alkenyl group include those in which one or more CH-CH structures existing in the above-mentioned alkyl groups are substituted with a C=C structure. More specifically, vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl, etc. The alkynyl group includes one or more CH ₂ -CH ₂ structures present in the aforementioned alkyl group substituted with a C≡C structure, and more specifically, ethynyl, 1-propynyl, and 2-propynyl are exemplified Wait.

The above-mentioned alkyl group, alkenyl group, and alkynyl group may have a substituent, and in addition, a ring structure may be formed by the substituent. In addition, the formation of a ring structure by a substituent means that the substituents or a part of the substituent and the parent skeleton are bonded to form a ring structure.

Examples of such substituents include halogen groups, hydroxyl groups, mercapto groups, nitro groups, aryl groups, organooxy groups, organothio groups, organosilyl groups, acyl groups, ester groups, thioesters ( thioester group, phosphate ester group, amide group, alkyl group, alkenyl group, alkynyl group.

Examples of the halogen group of the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The aryl group of the substituent includes a phenyl group. This aryl group may be substituted by the aforementioned other substituents.

The organooxy group of the substituent may represent a structure represented by O-R. The R may be the same or different, and examples include the aforementioned alkyl, alkenyl, alkynyl, and aryl groups. These Rs may also be substituted by the aforementioned substituents. Specific examples of the organic oxy group include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, heptoxy, and octoxy.

The organothiol group of the substituent may represent a structure represented by -S-R. Examples of this R include the aforementioned alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents. Specific examples of organic thiol groups include, for example, methyl thiol, ethyl thiol, propyl thiol, Butyl mercaptan, pentyl mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, etc.

The organosilyl group of the substituent may represent a structure _{represented by -Si-(R) 3.} The R may be the same or different, and examples include the aforementioned alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents. Specific examples of organosilyl groups include trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, Pentyldimethylsilyl, hexyldimethylsilyl, etc.

The acyl group of the substituent may represent a structure represented by -C(O)-R. Examples of this R include the aforementioned alkyl groups, alkenyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents. Specific examples of the acyl group include formyl, acetyl, propyl, butyryl, isobutyryl, pentamyl, isopentyl, benzyl and the like.

The ester group of the substituent may represent a structure represented by -C(O)O-R or -OC(O)-R. Examples of this R include the aforementioned alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents.

The thioester group of the substituent may represent a structure represented by -C(S)O-R or -OC(S)-R. Examples of this R include the aforementioned alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents.

The phosphate group of the substituent may represent a structure represented by -OP(O)-(OR) _2. The R may be the same or different, and examples include the aforementioned alkyl groups, alkenyl groups, alkynyl groups, and aryl groups. These Rs may also be substituted by the aforementioned substituents.

The amide group of the substituent can be expressed as -C(O)NH ₂ , or, -C(O)NHR, -NHC(O)R, -C(O)N(R) ₂ , -NRC(O) R represents the structure. The R may be the same or different, and examples include the aforementioned alkyl, alkenyl, alkynyl, and aryl groups. These Rs may also be substituted by the aforementioned substituents.

The aryl group of the substituent may be the same as the above-mentioned aryl group. This aryl group may be substituted by the aforementioned other substituents.

As the alkyl group of the substituent, the same ones as the aforementioned alkyl group can be mentioned. This alkyl group may be further substituted with the aforementioned other substituents.

Examples of the alkenyl group of the substituent are the same as the aforementioned alkenyl group. This alkenyl group may be substituted by the aforementioned other substituents.

As the alkynyl group of the substituent, the same as the aforementioned alkynyl group can be mentioned. This alkynyl group may be further substituted with the aforementioned other substituents.

Generally, when a bulky structure is introduced, the reactivity of the amine group or the alignment of the liquid crystal may be reduced. Therefore, A ₁ and A _{2 are more} preferably hydrogen atoms, or an alkyl group with 1 to 5 carbon atoms that may have substituents, particularly preferably A hydrogen atom, a methyl group or an ethyl group.

In the formulas (2) and (3), Y ₁ is a divalent organic group derived from a diamine, and examples thereof include the following Y-1 to Y-118.

In formula (Y-109), m and n are independently 1~11, m+n is 2~12, in formula (Y-114), h is 1~3, formula (Y-111), (Y- In 117), j is 0~3.

From the viewpoint of the liquid crystal alignment or pretilt angle of the obtained liquid crystal alignment film, Y _{1 is more} preferably at least one selected from the structure represented by the following formulas (5) and (6).

In formula (5), R ₁₂ is a single bond or a divalent organic group with 1 to 30 carbons, R ₁₃ is a hydrogen atom, a halogen atom or a monovalent organic group with 1 to 30 carbons, and a is a 1 to 4 Integer, when a is 2 or more, R ₁₂ and R ₁₃ may be the same or different from each other. R ₁₄ in formula (6) is a single bond, -O-, -S-, -NR ₁₅ -, amide bond , Ester bond, urea bond, or a divalent organic group with 1-40 carbon _{atoms, R 15} is a hydrogen atom or a methyl group.

Specific examples of formula (5) and formula (6) include the following structures.

When a structure with high linearity is used as a liquid crystal alignment film, it can improve the alignment of the liquid crystal, so Y ₁ is more preferably Y-7, Y-21, Y-22, Y-23, Y-25, Y-43, Y -44, Y-45, Y-46, Y-48, Y-63, Y-71, Y-72, Y-73, Y-74, Y-75, Y-98, Y-99, Y-100 , Y-118. The ratio of the above-mentioned structure that can improve the orientation of the liquid crystal is preferably _{20 mol% or more of the entire Y 1} , more preferably 60 mol% or more, and still more preferably 80 mol% or more.

As a liquid crystal alignment film, when the pretilt angle of the liquid crystal is to be increased, it is preferable that the side chain has a long-chain alkyl group, an aromatic ring, an aliphatic ring, a steroid skeleton, or Y ₁ has a structure combining these. Such Y _{1 is} preferably Y-76, Y-77, Y-78, Y-79, Y-80, Y-81, Y-82, Y-83, Y-84, Y-85, Y-86 , Y-87, Y-88, Y-89, Y-90, Y-91, Y-92, Y-93, Y-94, Y-95, Y-96, Y-97. When the pretilt angle is to be increased, the ratio of the above-mentioned structure is preferably _{1-30 mol% of the entire Y 1} , and more preferably 1-20 mol%.

The polyimide precursor used in the present invention is obtained by the reaction of a diamine component and a tetracarboxylic acid derivative, and examples thereof include polyamide acid or polyamide acid ester.

<(C) Ingredient>

The (C) component contained in the liquid crystal alignment agent of the present invention is a compound containing two or more crosslinkable functional groups. Examples of crosslinkable functional groups include hydroxyl groups, hydroxyalkylamido groups, (meth)acrylate groups, blocked isocyanate groups, oxetanyl groups, epoxy groups, etc., but are not limited thereto. Etc.

Among them, from the viewpoint of availability and voltage retention improvement effect, a hydroxyl group, a blocked isocyanate group, or an epoxy group is preferred, and a hydroxyl group or an epoxy group is more preferred. In addition, the structure of the component (C) may have two or more identical cross-linkable functional groups, or two or more different cross-linkable functional groups.

The compound containing two or more hydroxyl groups includes, for example, a compound represented by the following formula (7).

X ₃ is an aliphatic hydrocarbon group with 1 to 20 carbons, or an n-valent organic group containing an aromatic hydrocarbon group, n is an integer of 2 to 6, and R ₆ and R ₇ are each independently a hydrogen atom or may have a substituent The alkyl group having 1 to 4 carbons, the alkenyl group having 2 to 4 carbons, or the alkynyl group having 2 to 4 carbons, _{and at least one of R 6} and R ₇ is represented by the following formula (6).

R ₈ to R ₁₁ each independently represent any one of a hydrogen atom, a hydrocarbon group, or a hydrocarbon group substituted with a hydroxy group. _{As with the above, X 3 is} preferably an aliphatic hydrocarbon group from the viewpoint of liquid crystal alignment and solubility, and more preferably has a carbon number of 1-10. n represents an integer of 2-6, but from the viewpoint of solubility, n is preferably 2-4.

Specifically, the following compounds can be mentioned.

The compound containing two or more blocked isocyanate groups includes a compound represented by the following formula (9).

The four Zs are each independently an alkyl group having 1 to 3 carbon atoms, a hydroxyl group, or an organic group represented by the following formula (10), and at least one of Z is an organic group represented by the following formula (10).

Specifically, for example, the following compounds can be mentioned.

Examples of the compound containing two or more blocked isocyanate groups other than the above formula (11) include the following compounds.

Specific examples of the compound containing two or more epoxy groups include the following compounds.

Specific examples of the compound containing two or more (meth)acrylate groups include the following compounds.

Other examples include the following compounds.

<Proportion of each ingredient>

Regarding the content ratio of the (A) component, (B) component, and (C) component contained in the liquid crystal alignment agent of the present invention, the content ratio of the (A) component is in the liquid crystal alignment, preferably 20 to 80 % By mass, more preferably 20-60% by mass, particularly preferably 30-50% by mass.

Moreover, the content rate of (B) component is relative to (A) component, Preferably it is 20-80 mass %, More preferably, it is 40-80 mass %, Especially preferably, it is 50-70 mass %.

In addition, the content ratio of the above-mentioned (C) component is relative to the total of the (A) component and (B) component, and is preferably 1 to 30% by weight, more preferably 3 to 20% by weight, and particularly preferably 3 to 15% by weight %.

<Polyimide precursor-manufacturing of polyimide acid>

The polyimide precursor of the polyimide precursor used for the above-mentioned (A) component and (B) component is produced by the following method. Specifically, the tetracarboxylic acid component such as tetracarboxylic dianhydride and the diamine component are allowed to react for 30 minutes at -20°C to 150°C, preferably 0°C to 50°C, in the presence of an organic solvent. It is produced by reacting for 24 hours, preferably 1 to 12 hours.

The reaction of the diamine component and the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent used at this time is not particularly limited as long as it can dissolve the produced polyimide precursor. Specific examples of organic solvents used in the following reactions include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N,N-dimethylformamide, N , N-dimethyl acetamide, dimethyl sulfide or 1,3-dimethyl-imidazolinone.

In addition, when the polyimide precursor has high solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or the following formula can be used [D-1]~Organic solvent represented by formula [D-3].

In the formulas [D-1] to [D-3], D ¹ represents an alkyl group with 1 to 3 carbons, D ² represents an alkyl group with 1 to 3 carbons, and D ³ represents an alkyl group with 1 to 4 carbons.

These solvents can be used alone or in combination. In addition, even if it is a solvent that does not dissolve the polyimide precursor, it can be mixed and used in the aforementioned solvent within a range where the polyimide precursor produced does not precipitate. In addition, the moisture in the solvent will hinder the polymerization reaction and cause the resulting polyimide precursor to hydrolyze, so it is better to use dehydrated and dried solvents.

The concentration of the polyamide acid polymer in the reaction system is not easy to cause precipitation of the polymer, and it is easy to obtain a high molecular weight body, so it is preferably 1-30% by mass, more preferably 5-20% by mass.

The obtained polyamide acid can be precipitated and recovered by fully stirring the reaction solution and simultaneously injecting it into a weak solvent. In addition, by precipitating several times, washing with a weak solvent, and drying at room temperature or by heating, a purified polyamide powder can be obtained. The weak solvent is not particularly limited, and examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Production of Polyimide Precursor-Polyurate>

The polyamide ester of the polyimide precursor can be produced by the method (1), (2) or (3) shown below.

(1) When it is made of polyamide acid

The polyamide can be produced by esterifying the polyamide produced above. Specifically, the polyamide acid and esterification agent can be reacted for 30 minutes to 24 hours in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, preferably It takes 1 to 4 hours to manufacture.

The esterification agent is preferably one that can be easily removed by purification, and examples include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentylbutyl acetal, N,N-dimethylformamide di-t-butyl Acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4 -(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, etc. The addition amount of the esterification agent is 1 mol relative to the repeating unit of polyamide acid, preferably 2-6 mol.

Examples of organic solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide , Dimethyl sulfoxide or 1,3-dimethyl-imidazolinone. In addition, when the solvent solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or The solvent represented by the aforementioned formula [D-1] ~ formula [D-3].

These solvents can be used alone or in combination. In addition, even if it is a solvent that does not dissolve the polyimide precursor, the resulting polyimide precursor will not Within the range of precipitation, it can be mixed and used in the aforementioned solvent. In addition, the moisture in the solvent will hinder the polymerization reaction and cause the resulting polyimide precursor to hydrolyze, so it is better to use dehydrated and dried solvents.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone or γ -butyrolactone in terms of polymer solubility, and these can be used. One or two or more of them are mixed and used. The concentration at the time of manufacture is less likely to cause precipitation of the polymer, and from the viewpoint that a high molecular weight body is easily obtained, it is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass.

(2) Production by the reaction of tetracarboxylic acid diester dichloride and diamine

Polyurethane can be produced from tetracarboxylic acid diester dichloride and diamine.

Specifically, the tetracarboxylic acid diester dichloride and diamine can be reacted for 30 minutes at -20°C to 150°C, preferably 0°C to 50°C, in the presence of a base and an organic solvent. It is produced in 24 hours, preferably 1 to 4 hours.

As the aforementioned base, pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used, but pyridine is preferred for the stable progress of the reaction. The added amount of the base is an amount that is easy to remove and that a high-molecular-weight body is easily obtained, and it is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ -butyrolactone in terms of the solubility of monomers and polymers. These can be used singly or in combination of two or more. use. The polymer concentration at the time of production is less likely to cause precipitation of the polymer, and from the viewpoint that a high molecular weight body is easily obtained, it is preferably 1 to 30% by mass, more preferably 5 to 20% by mass. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the manufacture of the polyamide ester is preferably dehydrated as much as possible, and in order to prevent the mixing of external air, it is better to proceed in a nitrogen environment. .

(3) When it is made from tetracarboxylic acid diester and diamine

Polyurethane can be produced by polycondensation of tetracarboxylic acid diester and diamine. Specifically, the tetracarboxylic acid diester and diamine can be reacted at 0°C to 150°C, preferably 0°C to 100°C, for 30 minutes to 24 in the presence of a condensing agent, alkali, and organic solvent. Hours, preferably 3 to 15 hours.

The aforementioned condensing agent can use triphenyl phosphite, dicyclohexyl carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, N, N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholine, O-(benzotriazol-1-yl)-N,N,N',N'-tetra Methylurea tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylmethylurea hexafluorophosphate, (2,3-dihydro -2-thioxo-3-benzoxazolyl)phosphonic acid diphenyl ester and the like. The amount of condensing agent added is preferably 2 to 3 times the molar ratio of the tetracarboxylic acid diester.

As the aforementioned base, tertiary amines such as pyridine and triethylamine can be used. The added amount of the base is an amount that is easy to remove and that it is easy to obtain a high-molecular-weight body, and it is preferably 2 to 4 times mol relative to the diamine component.

Furthermore, in the above reaction, by adding a Lewis acid as an additive, the reaction proceeds efficiently. The Lewis acid is preferably lithium halide such as lithium chloride and lithium bromide. The amount of Lewis acid added is preferably 0 to 1.0 times mol relative to the diamine component.

Among the three methods for producing polyamides, in order to obtain high-molecular-weight polyamides, the production method of (1) or (2) is particularly preferred.

The polyamide acid ester solution obtained as described above is poured into a weak solvent while fully stirring, so that the polymer can be precipitated. After several times of precipitation and washing with a weak solvent, the purified polyamide ester powder can be obtained after drying at room temperature or by heating. The weak solvent is not particularly limited, but water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. can be mentioned.

<Polyimide>

The polyimide used in the present invention can be produced by imidizing the aforementioned polyamide ester or polyamide acid. In the case of producing polyimide from polyamide, add a basic catalyst to the polyamide solution described above or the polyamide solution obtained by dissolving polyamide resin powder in an organic solvent The chemical imidization is relatively simple. The chemical imidization is carried out at a relatively low temperature to carry out the imidization reaction. During the imidization process, the molecular weight of the polymer is not likely to decrease, so it is preferred.

The chemical imidization can be carried out by stirring the polyamide to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. In particular, triethylamine has sufficient basicity necessary for the reaction to proceed, so it is preferred.

The temperature during the imidization reaction is -20℃~140℃, It is preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of the alkaline catalyst is 0.5 to 30 mol times of the amide acid ester group, preferably 2 to 20 mol times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. In the solution after the imidization reaction, the added catalyst and the like remain, so the obtained imidized polymer is recovered by the following means, and re-dissolved in an organic solvent, as a liquid crystal alignment agent. good.

In the case of producing polyimide from polyamic acid, chemical imidization by adding a catalyst to the polyimide solution obtained by the reaction of a diamine component and tetracarboxylic dianhydride is relatively simple. The chemical imidization is carried out at a relatively low temperature, and the molecular weight of the polymer is not likely to decrease during the imidization process, so it is preferred.

The chemical imidization can be carried out by stirring the polyamide to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine has a moderate basicity required for the reaction, so it is preferred. Moreover, the acid anhydride includes acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. Among them, when acetic anhydride is used, purification after the completion of the reaction becomes easy, so it is preferred.

The temperature during the imidization reaction can be -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of alkaline catalyst is 0.5 to 30 mol times of the amide acid group, preferably 2 to 20 mol times, and the amount of acid anhydride is 1 to 50 mol times of the amide acid group, preferably 3 to 3 molar times. 30 mol Times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

In the solution after the imidization reaction of polyamide or polyamide, the added catalyst and the like remain in the solution, so the obtained imidization polymer is recovered by the method described below. The organic solvent is re-dissolved, which is preferred as the liquid crystal alignment agent of the present invention.

The polyimide solution obtained as described above can be poured into a weak solvent while fully stirring, so that the polymer can be precipitated. In addition, by precipitating several times, washing with a weak solvent, and drying at room temperature or by heating, a purified polyamide powder can be obtained.

The aforementioned weak solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and the like.

<Liquid crystal alignment agent>

The liquid crystal alignment agent of the present invention has the form of a solution in which the aforementioned specific polymer (A), specific polymer (B), and (C) components are dissolved in an organic solvent. The molecular weight of the specific polymer (A) and the specific polymer (B) preferably has a weight average molecular weight of 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000. In addition, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

The content (concentration) of the polymer containing the specific polymer (A) and the specific polymer (B) in the liquid crystal alignment agent of the present invention can be The thickness of the coating film to be formed can be changed as appropriate. However, when a uniform and defect-free coating film is formed, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. Among them, it is preferably 2 to 7% by mass, and particularly preferably 3 to 6% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer with a specific structure can be uniformly dissolved. For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfene, γ -Butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone or 4-hydroxy-4-methyl-2-pentanone, etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferred.

In addition, when the solubility of the polymer to the solvent is high, it is better to use the solvent represented by the aforementioned formula [D-1] to formula [D-3].

The good solvent in the liquid crystal alignment agent is preferably 20% by mass to 99% by mass of the total solvent contained in the liquid crystal alignment agent. Among them, 20 to 90% by mass is preferred. More preferably, it is 30 to 80% by mass.

The liquid crystal alignment agent of the present invention can use a solvent (also referred to as a weak solvent) that improves the coating property or surface smoothness of the liquid crystal alignment film when the liquid crystal alignment agent is applied to the range that does not impair the effects of the present invention. Specific examples of the following weak solvents can be cited, but are not limited to these examples.

Examples include ethanol, isopropanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1 -Butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol Alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methyl Cyclohexanol, 3-methylcyclohexanol, 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1 ,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, two Propyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol two Methyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone , 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethyl Glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2 -(Hexoxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1-(butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetic acid Ester, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy ) Ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate , N-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-methoxypropane Ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropyl propionate, 3-methoxy butyl propionate, methyl lactate, ethyl lactate, n-propyl lactate, N-butyl lactate, isoamyl lactate or the aforementioned formula [D-1] to formula [D-3].

Among them, preferred is 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, or dipropylene glycol dimethyl ether.

These weak solvents are preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent. Among them, it is preferably 10 to 80% by mass. More preferably, it is 20 to 70% by mass.

In addition to the above, the liquid crystal alignment agent of the present invention can also be added with polymers other than the polymer described in the present invention to change the dielectric constant or conductivity of the liquid crystal alignment film as long as it does not impair the effects of the present invention. Dielectrics or conductive materials for the purpose of properties, silane coupling agents for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, crosslinking compounds for the purpose of improving the hardness or density of the liquid crystal alignment film, and It is an imidization accelerator for the purpose of efficiently performing imidization by heating the polyimide precursor during the firing of the coating film.

<Liquid Crystal Alignment Film>

The liquid crystal alignment film of the present invention is a film obtained by coating the above-mentioned liquid crystal alignment agent on a substrate, drying and firing. The substrate coated with the liquid crystal alignment agent is not particularly limited as long as it is a highly transparent substrate. Plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, etc. can be used to simplify the process Point of view, use a liquid crystal drive formed with A substrate such as an ITO (Indium Tin Oxide) electrode is preferable. In addition, in the case of a reflective liquid crystal display element, when only a single-sided substrate is used, an opaque material such as a silicon wafer can also be used. In this case, a light-reflecting material such as aluminum can also be used for the electrode.

The coating method of the liquid crystal alignment agent includes a spin coating method, a printing method, an inkjet method, and the like. Any temperature and time can be selected for the drying and firing steps after coating the liquid crystal alignment agent. Generally, in order to fully remove the organic solvent contained, it is dried at 50°C to 120°C for 1 minute to 10 minutes, and then fired at 150°C to 300°C for 5 minutes to 120 minutes. The thickness of the coating film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may decrease, so it is 5 to 300 nm, preferably 10 to 200 nm.

The method of subjecting the obtained liquid crystal alignment film to alignment treatment includes a rubbing method, a photo-alignment treatment method, and the like.

The rubbing treatment can use the existing rubbing device. The material of the friction cloth at this time can be cotton, nylon, rayon, etc. The conditions of friction treatment generally use the conditions of rotation speed of 300~2000rpm, conveying speed of 5~100mm/s, and pushing amount of 0.1~1.0mm. Then, using pure water, alcohol, etc., ultrasonic cleaning is used to remove residues caused by friction.

Specific examples of the photo-alignment treatment method include a method of irradiating the surface of the coating film with radiation deviated in a certain direction, and sometimes heating treatment at a temperature of 150-250°C to impart alignment energy to the liquid crystal. The radiation can use ultraviolet and visible light with a wavelength of 100~800nm. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferred, and those having a wavelength of 200 to 400 nm are particularly preferred. In addition, in order to improve the orientation of the liquid crystal, the coated substrate may be heated at 50 to 250°C while irradiating with radiation. The irradiation amount of the aforementioned radiation is preferably 1 to 10,000 mJ/cm ² , particularly preferably 100 to 5,000 mJ/cm ² . As mentioned above, the liquid crystal alignment film can stabilize the alignment of liquid crystal molecules in a specific direction.

The higher the extinction ratio of polarized ultraviolet light, the higher the anisotropy can be imparted, so it is better. Specifically, the extinction ratio of linearly polarized ultraviolet rays is preferably 10:1 or more, more preferably 20:1 or more.

The film irradiated with polarized radiation may then contain at least one solvent selected from water and organic solvents for contact treatment.

The solvent used in the contact treatment is not particularly limited as long as it can dissolve the decomposed product generated by light irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve Agents, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate, etc. Two or more of these solvents can be used in combination.

From the viewpoint of versatility or safety, it is more preferably at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate. Particularly preferred are water, 2-propanol, and a mixed solvent of water and 2-propanol.

The contact treatment between the film irradiated with polarized radiation and the solution containing the organic solvent is carried out under a treatment such as immersion treatment, spray treatment, etc., to make the film and the liquid sufficiently contact. Among them, in a solution containing an organic solvent, it is preferably 10 seconds to 1 hour, more preferably 1 to 30 minutes. The method of immersing the membrane is better. The contact treatment can be carried out at room temperature or heating, preferably at 10 to 80°C, more preferably at 20 to 50°C. In addition, if necessary, a means to improve contact such as ultrasound may be implemented.

After the above-mentioned contact treatment, in order to remove the organic solvent in the use solution, either water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone and other low-boiling solvents can be used for washing (washing) or drying. One or both.

In addition, the above-mentioned film subjected to contact treatment with a solvent can be heated at a temperature above 150°C for the drying of the solvent and the realignment of the molecular chains in the film.

The heating temperature is preferably 150 to 300°C. The higher the temperature, the more the realignment of the molecular chain can be promoted, but when the temperature is too high, there are doubts about the decomposition of the molecular chain. Therefore, the heating temperature is more preferably 180 to 250°C, particularly preferably 200 to 230°C.

When the heating time is too short, the realignment effect of the molecular chains may not be obtained. When the heating time is too long, the molecular chains may be decomposed, preferably 10 seconds to 30 minutes, more preferably 1 minute to 10 minutes.

<Liquid crystal display element>

The liquid crystal display element of the present invention is provided with a liquid crystal alignment film obtained by the aforementioned method for manufacturing a liquid crystal alignment film. The liquid crystal display element is obtained by using the liquid crystal alignment agent through the aforementioned method of manufacturing the liquid crystal alignment film to obtain the substrate with the liquid crystal alignment film, and then the liquid crystal cell is fabricated by a conventional method, and the liquid crystal cell is used to make the liquid crystal display element.

A liquid crystal display element with a passive matrix structure as an example of a liquid crystal cell manufacturing method is described. Alternatively, it may be a liquid crystal display element of an active matrix structure in which switching elements such as TFT (Thin Film Transistor) are provided in each pixel portion constituting the image display.

First, a substrate made of transparent glass is prepared, a common electrode (Common Electrode) is provided on one of the substrates, and a segment electrode (segment electrode) is provided on the other substrate. These electrodes, for example, can be used as ITO electrodes, and are patterned to display desired images. Secondly, on each substrate, an insulating film is provided to cover the common electrode and the segment electrode. The insulating film may be, for example, a film made of SiO ₂ -TiO ₂ formed by a sol-gel method.

Secondly, the liquid crystal alignment film of the present invention is formed on each substrate. Next, the alignment film surfaces of one of the substrates and the other substrate are opposed to each other to overlap, and the periphery is bonded with a sealing material. In order to control the gap between the substrates in the sealing material, a spacer can usually be mixed. In addition, it is preferable to spread spacers for substrate gap control on the in-plane portion where the sealing material is not provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.

Next, through the opening provided in the sealing material, the liquid crystal material is injected into the space surrounded by the two substrates and the sealing material. Then, the opening is sealed with an adhesive. When injecting, a vacuum injection method can be used, or a method using capillary phenomenon in the atmosphere can be used. Secondly, set the polarizing plate. Specifically, a pair of polarizing plates are pasted on the surface opposite to the liquid crystal layer of the two substrates. Through the above steps, the liquid crystal display element of the present invention can be obtained.

As the sealing agent, for example, a resin having a reactive group such as an epoxy group, an acryl group, a methacryl group, a hydroxyl group, an allyl group, and an acetyl group can be cured by ultraviolet irradiation or heating. In particular, it is preferable to use a hardening resin system having reactive groups of both epoxy groups and (meth)acrylic groups.

In order to improve the adhesion and moisture resistance of the sealant, inorganic fillers can also be formulated. The inorganic fillers that can be used are not particularly limited. Specifically, examples include spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, and boron nitride. , Calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconia, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, titanium Barium oxide, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate , Barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, aluminum silicate. The aforementioned inorganic fillers can also be used in combination of two or more kinds.

[Example]

Examples are given below to illustrate the present invention in more detail, but the present invention is not limited to these. The abbreviations and measurement methods of the compounds below are as follows.

NMP: N-methyl-2-pyrrolidone, GBL: γ-butyl lactone

BCS: butyl cellosolve, PB: propylene glycol monobutyl ether, IPA: isopropanol, DA-1: 1,2-bis(4-aminophenoxy)ethane DA-2: Refer to the following formula (DA-2), DA-3: 1,2-bis(4-aminophenoxy)methane, DA-4: p-phenylenediamine, DA-5: 1, 2-bis(4-aminophenoxy)propane

DA-6: Refer to the following formula (DA-6), DA-7: 4,4' diaminodiphenylamine, DA-8: Refer to the following formula (DA-8), DA-9: 4, 4'Diaminodiphenylmethane, DAH-1: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

DAH-2: Refer to the following formula (DAH-2), DAH-3: Refer to the following formula (DAH-3)

DAH-4: Cyclobutane tetracarboxylic dianhydride

DAH-5: pyromellitic dianhydride

1,3DM-CBDE-Cl: Dimethyl 1,3-bis(chlorocarbonyl)-1,3-dimethylcyclobutane-2,4-dicarboxylate

[additive]

AD-1~3: Crosslinking additives, AD-4: Imidization accelerator

[ ¹ H NMR]

Device: Fourier transform type superconducting nuclear magnetic resonance device (FT-NMR) INOVA-400 (manufactured by Varian) 400MHz, solvent: deuterated dimethyl sulfoxide (DMSO-d ₆ ))

Standard material: Tetramethylsilane (TMS), cumulative number of times: 8 or 32

[Viscosity]

In the synthesis example, the viscosity of the polyimide and polyamic acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a cone rotor TE-1 (1°34' , R24), and the temperature is 25°C for measurement.

[Molecular weight]

The molecular weight of polyimide is measured by a GPC (normal temperature gel permeation chromatography) device, and the number average molecular weight (Mn) and weight average molecular weight (Mw) are calculated using polyethylene glycol and polyethylene oxide conversion values.

GPC device: manufactured by Shodex Corporation (GPC-101),

Column: manufactured by Shodex Corporation (in-line of KD803 and KD805), column temperature: 50°C

Eluent: N,N-dimethylformamide (additive is lithium bromide-hydrate (LiBr. H ₂ O) 30mmol/L (liter), phosphoric acid. Anhydrous crystal (o-phosphoric acid) is 30mmol/L, tetrahydrofuran (THF) is 10ml/L, flow rate: 1.0ml/min

Standard sample for calibration line production: TSK standard polyethylene oxide manufactured by Tosoh Corporation (weight average molecular weight (Mw) approximately 900,000, 150,000, 100,000, 30,000), and polyethylene glycol manufactured by Polymer Laboratories (peak top molecular weight) (Mp) about 12,000, 4,000, 1,000). In order to avoid overlapping of the peaks, the two samples were mixed with 4 types of samples of 900,000, 100,000, 12,000, and 1,000, and 2 samples were mixed with 3 types of samples of 150,000, 30,000, and 4,000. Line measurement.

[Measurement of imidization rate]

Put 20mg of polyimide powder into an NMR sample tube (NMR sampling tube stand, Φ5 (manufactured by Kusano Science)), and add a mixture of deuterated dimethyl sulfide (DMSO-d6, 0.05% TMS (tetramethylsilane)) ) (0.53ml), apply ultrasound to make it completely dissolved. This solution was used to measure proton NMR at 500 MHz using an NMR measuring machine (JNW-ECA500) (manufactured by JEOL Datum). The rate of imidization is based on the protons from the unchanged structure before and after imidization as the reference proton, using the peak cumulative value of this proton and the NH group from the imidic acid that appears near 9.5 ppm to 10.0 ppm. The cumulative value of the proton peak of is obtained by the following formula.

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

In the above formula, x is the peak cumulative value of protons derived from the NH group of amide acid, y is the cumulative peak value of reference protons, and the number of reference protons when α-based polyamide acid (the imidization rate is 0%) Relative to the ratio of 1 NH proton of amide acid.

[Evaluation of Liquid Crystal Orientation]

The liquid crystal cell is clamped by a polarizing plate, and the liquid crystal cell is rotated under the state of illuminating the backlight from the back to visually observe the change of light and darkness or the presence or absence of flow alignment, and whether the liquid crystal is aligned or not. At this time, it was evaluated based on the following criteria.

Evaluation criteria

◎: The alignment of the liquid crystal can be confirmed, and there is no flow alignment

○: Although the liquid crystal is aligned, some flow alignment is observed

×: The liquid crystal is aligned, but many flow alignments are observed.

(Synthesis example 1)

Weigh DA-1 (42.75g (175mmol)) and DA-2 (59.7g (175mmol)) in a 1000mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, and then add 586g of NMP, while adding nitrogen Dissolve while stirring. While stirring this diamine solution, DAH-1 (74.53 g (332.5 mmol)) was added, and NMP was added to make the solid content concentration 18% by mass. The mixture was stirred at room temperature for 24 hours to obtain polyamide acid (PAA- 1) Solution (viscosity: 832mPa·s).

(Synthesis example 2)

In a 1000 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh 200 g of the obtained polyamide acid solution (PAA-1), add NMP (100 g), and stir for 30 minutes. 21.78 g of acetic anhydride and 2.81 g of pyridine were added to the obtained polyamide acid solution, and the mixture was heated at 60°C for 3 hours to perform chemical imidization. The obtained reaction liquid was poured into 624.2 g of methanol while stirring, and the precipitated precipitate was filtered out, and then washed with 624.2 g of methanol 3 times and 1248 g of methanol 2 times. The obtained resin powder was dried at 60°C for 12 hours. The polyimide resin powder was obtained. this The imidization rate of polyimide resin powder is 68%, and the molecular weight is Mn=9189 and Mw=18252.

In a 200ml sample tube containing a stir bar, weigh 32.70g of the obtained polyimide resin powder, add 239.8g of NMP, and stir at 70°C for 20 hours to dissolve to obtain a polyimide solution (SPI-1) .

(Synthesis example 3)

In a 100 mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-3 (7.14 g (31 mmol)), add 75.1 g of a 1:1 mixed solvent of NMP and GBL, and stir while feeding nitrogen. Dissolve. While stirring this diamine solution, DAH-3 (2.33 g (9.3 mmol)) was added, and stirring was performed overnight. Then, DAH-2 (6.13 g (20.8 mmol)) was added, a 1:1 mixed solvent of NMP and GBL was added to make the solid content concentration 15% by weight, and the mixture was stirred at room temperature for 5 hours to obtain polyamide acid ( PAA-2) solution (viscosity: 787mPa·s).

(Synthesis example 4)

In a 100mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-3 (5.53g (24mmol)), add 72.7g of a 1:1 mixed solvent of NMP and GBL, and stir while feeding nitrogen. Dissolve. While stirring this diamine solution, add DAH-2 (6.87 g (23.4 mmol)), add a 1:1 mixed solvent of NMP and GBL to make the solid content concentration 12% by weight, and stir overnight to obtain polyamide acid (PAA-3) solution (viscosity: 520mPa·s).

(Synthesis Example 5)

In a 100mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-4 (0.908g (8.4mmol)), DA-1 (1.37g (5.6mmol)), DA-5 (2.17g ( 8.4 mmol)), DA-6 (2.23 g (5.6 mmol)), 76.8 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, add DAH-1 (5.99g (26.7mmol)), add NMP to make the solid content concentration 12% by weight, and stir overnight to obtain a polyamide acid (PAA-4) solution (viscosity) : 397mPa.s).

(Synthesis Example 6)

In a 500mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-7 (15.9g (80mmol)) and DA-8 (6.0g (20mmol)), add 230.0g of NMP, and then add nitrogen. Dissolve while stirring. While stirring this diamine solution, DAH-4 (4.4 g (22.5 mmol)) was added, and stirring was performed overnight. Then, DAH-3 (18.8g (75mmol)) was added, NMP was added to make the solid content concentration 15% by weight, and the mixture was stirred at 50°C for 10 hours to obtain a polyamide acid (PAA-5) solution (viscosity: 1405mPa) .S).

(Synthesis Example 7)

Weigh DA-7 (1.91g (9.6mmol)) and DA-8 (0.72g) in a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube (2.4mmol)), add a 1:1 mixed solvent of NMP and GBL, and stir to dissolve while feeding nitrogen. While stirring this diamine solution, DAH-2 (3.40 g (11.6 mmol)) was added, a 1:1 mixed solvent of NMP and GBL was added to make the solid content concentration 12% by weight, and stirring was performed overnight to obtain polyamide acid ( PAA-6) solution (viscosity: 810mPa·s).

(Synthesis example 8)

In a 2L four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-4 (10.00g (92.4mmol)) and DA-1 (13.60g (55.5mmol)), DA-2 (12.60g ( 37.0mmol)), NMP 379.00g, GBL 1023.00g and pyridine 34.60g (0.43mol) were added and dissolved. Next, while stirring this solution, 1,3DMCBDE-Cl (58.30 g (179.4 mmol)) was added, and it was made to react under water cooling for 14 hours. 2.41 g (26.6 mmol) of acryloyl chloride was added to the obtained polyamide acid solution, and after the reaction was carried out for 4 hours, the solution was poured into 8653 ml of isopropanol while stirring, and the precipitated white precipitate was collected by filtration. Next, 21,635 ml of isopropanol was divided into five uses, washed, and dried to obtain white polyamide resin powder (PWD-1). The molecular weight of this polyamide ester is Mn=24,366 and Mw=54,808.

The polyamide resin powder (PWD-1) obtained above was dissolved in GBL to obtain a polyamide resin solution (PAE-1) having a solid content of 12% by mass.

(Synthesis Example 9)

In a 100 mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-7 (2.23 g (11.2 mmol)) and DA-9 (0.56 g (2.8 mmol)), add 26.4 g of NMP, and deliver Add nitrogen while stirring to dissolve. While stirring this diamine solution, DAH-3 (2.63 g (9.3 mmol)) was added, and 4.4 g of NMP was added, and the mixture was stirred at room temperature for 3 hours. Then, DAH-4 (0.58 g (2.94 mmol)) was added, a 1:1 mixed solvent of NMP and GBL was added to make the solid content concentration 12% by weight, and stirring was performed overnight at room temperature to obtain polyamide acid (PAA-7) solution (viscosity: 630mPa·s).

(Synthesis example 10)

In a 100 mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh DA-7 (3.99 g (20 mmol)) and DA-9 (0.99 g (5.0 mmol)), add 74.8 g of NMP, and then feed it Dissolve while stirring under nitrogen. While stirring this diamine solution, DAH-2 (5.15 g (17.5 mmol)) was added, and the mixture was stirred at room temperature for 5 hours. Then, DAH-4 (1.20 g (6.13 mmol)) was added, NMP was added so that the solid content concentration was 12% by weight, and the mixture was stirred overnight to obtain a polyamide acid (PAA-8) solution (viscosity: 398 mPa·s).

(Synthesis Example 11)

Weigh DA-5 (3.10g (12mmol)) and DA-6 (4.78g (12mmol)) in a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, add 74.5g of NMP, and then add nitrogen Dissolve while stirring solution. While stirring this diamine solution, add DAH-5 (4.97g (22.8mmol)), add NMP to make the solid content concentration 12% by weight, and stir overnight to obtain a polyamide acid (PAA-9) solution (viscosity) : 273mPa.s).

(Example 1)

In a 50 mL Erlenmeyer flask containing stirring, 2.929 g of the polyimide solution (SPI-1) obtained in Synthesis Example 2 and 4.62 g of the polyimide acid solution (PAA-2) obtained in Synthesis Example 3 were weighed. Add 2.83g of NMP, 3.45g of GBL, 3.60g of PB, then add 0.495g of 10% NMP solution of AD-1, AD-4 (0.139g), and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-1 ).

(Example 2)

In a 50 mL Erlenmeyer flask containing stirring, 2.929 g of the polyimide solution (SPI-1) obtained in Synthesis Example 2 and 4.62 g of the polyimide acid solution (PAA-2) obtained in Synthesis Example 3 were weighed. 3.32g of NMP, 3.45g of GBL, 3.60g of PB, AD-2 (0.0297g) and AD-4 (0.139g) were added, and the mixture was stirred with a magnetic stirrer overnight to obtain a liquid crystal alignment agent (AL-2).

(Example 3)

In a 50 mL Erlenmeyer flask containing stirring, weigh 2.929 g of the polyimide solution (SPI-1) obtained in Synthesis Example 2 and the polyimide solution (SPI-1) obtained in Synthesis Example 3 Amino acid solution (PAA-2) 4.62g. 3.32g of NMP, 3.45g of GBL, 3.60g of PB, AD-3 (0.0297g) and AD-4 (0.139g) were added, and the mixture was stirred with a magnetic stirrer overnight to obtain a liquid crystal alignment agent (AL-3).

(Comparative example 1)

In a 50 mL Erlenmeyer flask containing stirring, 2.929 g of the polyimide solution (SPI-1) obtained in Synthesis Example 2 and 4.62 g of the polyimide acid solution (PAA-2) obtained in Synthesis Example 3 were weighed. Add 3.32 g of NMP, 3.45 g of GBL, 3.60 g of PB, and AD-4 (0.139 g), and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-A).

(Comparative example 2)

In a 50 mL Erlenmeyer flask containing stirring, 2.929 g of the polyimide solution (SPI-1) obtained in Synthesis Example 2 and 5.90 g of the polyimide solution (PAA-3) obtained in Synthesis Example 4 were weighed. Add 2.19g of NMP, 2.81g of GBL, 3.60g of PB, add 0.495g of 10% NMP solution of AD-1, AD-4 (0.139g), stir overnight with a magnetic stirrer to obtain liquid crystal alignment agent (AL-B) .

(Example 4)

In a 50 mL Erlenmeyer flask containing stirring, 3.249 g of the polyamide acid solution (PAA-4) obtained in Synthesis Example 5 and 3.60 g of the polyamide acid solution (PAA-5) obtained in Synthesis Example 6 were weighed. Add NMP 5.40g, BCS 5.40 g, 0.45 g of AD-1 10% NMP solution was added, and stirred overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-4).

(Example 5)

In a 50 mL Erlenmeyer flask containing stirring, 3.249 g of the polyamide acid solution (PAA-4) obtained in Synthesis Example 5 and 3.60 g of the polyamide acid solution (PAA-5) obtained in Synthesis Example 6 were weighed. Add 5.85 g of NMP and 5.40 g of BCS, add AD-2 (0.027 g), and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-5).

(Example 6)

In a 50 mL Erlenmeyer flask containing stirring, 3.249 g of the polyamide acid solution (PAA-4) obtained in Synthesis Example 5 and 3.60 g of the polyamide acid solution (PAA-5) obtained in Synthesis Example 6 were weighed. Add 5.85 g of NMP and 5.40 g of BCS, add AD-3 (0.045 g), and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-6).

(Comparative example 3)

In a 50 mL Erlenmeyer flask containing stirring, 3.249 g of the polyamide acid solution (PAA-4) obtained in Synthesis Example 5 and 3.60 g of the polyamide acid solution (PAA-5) obtained in Synthesis Example 6 were weighed. Add 5.85 g of NMP and 5.40 g of BCS, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-C).

(Comparative Example 4)

In a 50 mL Erlenmeyer flask containing stirring, 3.249 g of the polyamide acid solution (PAA-4) obtained in Synthesis Example 5 and 4.58 g of the polyamide acid solution (PAA-6) obtained in Synthesis Example 7 were weighed. Add 4.42 g of NMP and 5.40 g of BCS, and then add 0.45 g of AD-1 10% NMP solution, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-D).

(Example 7)

In a 50 mL Erlenmeyer flask containing stirring, 3.30 g of the polyamide acid solution (PAE-1) obtained in Synthesis Example 8 and 3.96 g of the polyamide acid solution (PAA-7) obtained in Synthesis Example 9 were weighed. Add 1.54 g of NMP, 5.12 g of GBL, 3.60 g of BCS, and add 0.495 g of 10% NMP solution of AD-1, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-7).

(Comparative Example 5)

In a 50 mL Erlenmeyer flask containing stirring, 3.30 g of the polyamide acid solution (PAE-1) obtained in Synthesis Example 8 and 3.96 g of the polyamide acid solution (PAA-7) obtained in Synthesis Example 9 were weighed. Add NMP 2.03g, GBL 5.12g, and BCS 3.60g, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-E).

(Comparative Example 6)

In a 50mL Erlenmeyer flask containing a stirring, weigh out the synthesis example 8 3.30 g of the obtained polyamide acid ester solution (PAE-1) and 4.94 g of the polyamide acid solution (PAA-8) obtained in Synthesis Example 10. Add 0.56g of NMP, 5.12g of GBL, 3.60g of BCS, and add 0.495g of 10% NMP solution of AD-1, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-F).

(Example 8)

In a 50 mL Erlenmeyer flask containing stirring, 1.87 g of the polyamide acid solution (PAA-9) obtained in Synthesis Example 11 and 4.80 g of the polyamide acid solution (PAA-7) obtained in Synthesis Example 9 were weighed. Add 5.58 g of NMP and 5.40 g of BCS, and then add 0.45 g of AD-1 10% NMP solution, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-8).

(Comparative Example 7)

In a 50 mL Erlenmeyer flask containing stirring, 1.87 g of the polyamide acid solution (PAA-9) obtained in Synthesis Example 11 and 4.80 g of the polyamide acid solution (PAA-7) obtained in Synthesis Example 9 were weighed. Add 6.03 g of NMP and 5.40 g of BCS, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-G).

(Comparative Example 8)

In a 50 mL Erlenmeyer flask containing stirring, 1.87 g of the polyamide acid solution (PAA-9) obtained in Synthesis Example 11 and 5.99 g of the polyamide acid solution (PAA-8) obtained in Synthesis Example 10 were weighed. Join NMP 4.50g, BCS 5.40g, and then add 0.45g of AD-1 10% NMP solution, and stir overnight with a magnetic stirrer to obtain a liquid crystal alignment agent (AL-H).

(Example 9)

After filtering the liquid crystal alignment agent (AL-1) obtained in Example 1 with a filter with a pore size of 1.0 μm, it was spin-coated on a glass substrate with a transparent electrode, and dried on a hot plate at a temperature of 80° C. for 2 minutes. Then, it was fired in a hot air circulating oven at a temperature of 230° C. for 20 minutes to obtain an imidized film with a film thickness of 110 nm. For the fired film, 200mJ/cm ² of 254nm ultraviolet rays were irradiated through a polarizing plate. Then, the substrate was washed with a mixed solvent of IPA/water=1:1 for 5 minutes, and then fired in a hot air circulating oven at 230°C for 20 minutes. In this way, a substrate with a liquid crystal alignment film is obtained.

In order to evaluate the electrical characteristics of the liquid crystal cell, two of the above-mentioned substrates with a liquid crystal alignment film were prepared, and one of the liquid crystal alignment films was sprinkled with a 6 μm spacer. The sealant is printed on it to make the liquid crystal alignment film faces face each other and the optical alignment direction becomes parallel. After bonding another substrate, the sealant is hardened to produce an empty cell. The liquid crystal ML-7026-100 (manufactured by Merck. Japan) was injected into the empty cell by a reduced pressure injection method, and the injection port was closed to obtain an IPS liquid crystal cell. The results of evaluating the initial orientation of this liquid crystal cell based on the above-mentioned criteria are shown in Table 1 below. The empty unit cell is heat-treated at 120° C. for 30 minutes to complete the liquid crystal cell.

In addition, after the above-mentioned liquid crystal cell was placed on a backlight for 3 days to be matured, a voltage of 1V was applied for 60μs at a temperature of 60°C, and the voltage after 500ms was measured to determine how much the voltage can be maintained as the voltage retention rate.

(Examples 10 and 11, Comparative Examples 9, 10)

Except that the liquid crystal alignment agent shown in Table 1 was used instead of the liquid crystal alignment agent AL-1, the same procedure as in Example 9 was performed to produce a liquid crystal cell for evaluation. The results of initial alignment and voltage retention of each liquid crystal cell are shown in Table 1.

(Example 12)

After filtering the liquid crystal alignment agent (AL-4) obtained in Example 4 with a filter with a pore size of 1.0 μm, it was spin-coated on a glass substrate with a transparent electrode, and dried on a hot plate at a temperature of 80° C. for 2 minutes. Then, it was fired in a hot-air circulating oven at a temperature of 230° C. for 30 minutes to obtain an imidized film with a film thickness of 100 nm. For the fired film, 150 mJ/cm ² of ultraviolet rays at 254 nm were irradiated through a polarizing plate. Then, it is fired in a hot air circulating oven at 230°C for 30 minutes. In this way, a substrate with a liquid crystal alignment film is obtained.

In order to evaluate the electrical characteristics of the liquid crystal cells, two of the above-mentioned substrates with a liquid crystal alignment film were prepared, and one of the liquid crystal alignment films was sprinkled with a spacer of 6 μm. The sealant is printed on it to make the liquid crystal alignment film faces face each other and the optical alignment direction becomes parallel. After bonding another substrate, the sealant is hardened to produce an empty cell. The liquid crystal ML-7026-100 (manufactured by Merck. Japan) was injected into the empty cell by a reduced pressure injection method, and the injection port was closed to obtain an IPS liquid crystal cell. The results of evaluating the initial orientation of this liquid crystal cell based on the above-mentioned criteria are shown in Table 1 below. The empty unit cell is heat-treated at 120°C for 30 minutes Complete the liquid crystal cell.

In addition, after the above-mentioned liquid crystal cell was placed on a backlight for 3 days to be matured, a voltage of 1V was applied for 60μs at a temperature of 60°C, and the voltage after 500ms was measured to determine how much the voltage can be maintained as the voltage retention rate.

(Examples 13, 14, Comparative Examples 11, 12)

Except that the liquid crystal alignment agent shown in Table 1 was used instead of the liquid crystal alignment agent AL-4, the same procedure as in Example 9 was performed to produce a liquid crystal cell for evaluation. The results of the initial alignment and voltage retention of each liquid crystal cell are shown in Table 1.

(Example 16)

After filtering the liquid crystal alignment agent (AL-8) obtained in Example 8 with a filter with a pore size of 1.0 μm, it was spin-coated on a glass substrate with a transparent electrode, and dried on a hot plate at a temperature of 80° C. for 2 minutes. Then, it was fired in a hot air circulating oven at a temperature of 230°C for 20 minutes to obtain an imidized film with a film thickness of 110 nm. For the fired film, the alignment treatment is performed by rubbing. Then, it was washed with running water for 1 minute and dried at 80°C for 10 minutes. In this way, a substrate with a liquid crystal alignment film is obtained.

In order to evaluate the electrical characteristics of the liquid crystal cells, two of the above-mentioned substrates with a liquid crystal alignment film were prepared, and one of the liquid crystal alignment films was sprinkled with a 6 μm spacer. The sealant is printed on it so that the liquid crystal alignment film faces face each other and the optical alignment direction becomes parallel. After bonding another substrate, the sealant is hardened to produce an empty cell. The liquid crystal ML-7026-100 (Merck. Japan Inc.) was injected into this empty cell, and the injection port was closed to obtain an IPS liquid crystal cell. The results of evaluating the initial orientation of this liquid crystal cell based on the above-mentioned criteria are shown in Table 1 below. The empty unit cell is heat-treated at 120° C. for 30 minutes to complete the liquid crystal cell.

In addition, after the above-mentioned liquid crystal cell was matured on a backlight for 3 days, a voltage of 1V was applied for 60μs at a temperature of 20°C, and the voltage after 500ms was measured to find out how much the voltage can be maintained as the voltage retention rate.

(Comparative Examples 15, 16)

Except that the liquid crystal alignment agent shown in Table 1 was used instead of the liquid crystal alignment agent AL-4, the same procedure as in Example 16 was performed to produce a liquid crystal cell for evaluation. The results of initial alignment and voltage retention of each liquid crystal cell are shown in Table 1.

The above results are shown in Table 1. In Table 1, Component 1 refers to a polymer component containing a thermal release group.

[Industrial availability]

The liquid crystal display element having the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is suitable for use as a wide range of displays such as liquid crystal televisions, smart phones, and car navigation.

In addition, the entire contents of the specification, scope of patent application, and abstract of Japanese Patent Application No. 2016-001659 filed on January 7, 2016 are cited here as the disclosure content of the specification of the present invention.

Claims (10)

A liquid crystal alignment agent containing the following (A) component, (B) component, (C) component and organic solvent, (A) component: using a tetracarboxylic acid derivative component and containing the following formula [A At least one diamine compound of a diamine compound having a structure of -1], a diamine compound having a structure of the following formula [A-2], and a diamine compound having a structure of the following formula [A-3] The polyimide precursor obtained from the diamine component and at least one polymer selected from the polyimide,

(R ¹ and R ² are each independently a hydrogen atom, an alkyl group with 1 to 4 carbon atoms, or a group represented by the following formula (1), at least one of which is a protective group that is substituted by heat to a hydrogen atom. R ₃ , R ₄ , and R ₅ are each independently a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms that may have a substituent, and D is a thermally desorbable group that is substituted into a protective group for a hydrogen atom by heat , The aforementioned thermally detachable group is a group represented by the following formula (1), or a tertiary butoxycarbonyl group,

(A is a single bond or a divalent group formed by a hydrocarbon group with 1 to 4 carbon atoms) (B) component: selected from polyimide precursors having a structural unit represented by the following formula (2) and the polyimide At least one type of polymer in the group of imine precursors,

(X ₁ is a tetravalent organic group represented by the following formula (X-1), Y ₁ is a divalent organic group, R ₁ is a hydrogen atom, or an alkyl group with 1 to 5 carbon atoms, each of _{A 1} ~A ₂ Independently a hydrogen atom, or an alkyl group with 1 to 10 carbons, an alkenyl group with 2 to 10 carbons, or an alkynyl group with 2 to 10 carbons that may have substituents)

(C) Component: Contains at least one crosslinking property selected from hydroxyl group, hydroxyalkylamido group, (meth)acrylate group, blocked isocyanate group, oxetanyl group and epoxy group. Functional compounds. For example, the liquid crystal alignment agent of the first item in the scope of patent application, wherein the aforementioned compound containing two or more cross-linkable functional groups is a compound containing two or more hydroxyl groups. For example, the liquid crystal alignment agent of the first item in the scope of the patent application, wherein the aforementioned compound containing two or more crosslinkable functional groups contains 0.1-20% by mass relative to the total of (A) component and (B) component. For example, the liquid crystal alignment agent of any one of items 1 to 3 in the scope of patent application, wherein the compound containing two or more crosslinkable functional groups is represented by the following formula (7),

(X ₃ is an aliphatic hydrocarbon group with 1-20 carbon atoms, or an n-valent organic group containing an aromatic hydrocarbon group, n is an integer of _2-6 , R 6 and R ₇ are each independently a hydrogen atom, or may have a substituent The alkyl group with 1 to 4 carbons, the alkenyl group with 2 to 4 carbons, or the alkynyl group with 2 to 4 carbons _{, at least one of R 6} and R ₇ represents a hydrocarbon group substituted with a hydroxy group). For example, the liquid crystal alignment agent of item 4 of the scope of patent application, wherein _{at least one of R 6} and R ₇ is represented by the following formula (8),

(R ₈ to R ₁₁ each independently represent a hydrogen atom, a hydrocarbon group, or a hydrocarbon group substituted with a hydroxyl group). For example, the liquid crystal alignment agent of any one of items 1 to 3 in the scope of patent application, wherein component (C) is a compound represented by the following formula,

For example, the liquid crystal alignment agent of any one of items 1 to 3 in the scope of the patent application, wherein the polymer of the aforementioned component (B) further has a structural unit represented by the following formula (3),

(X ₂ is a tetravalent organic group (except for the aforementioned formula (X-1)), Y ₁ is a divalent organic group, R ₁ is a hydrogen atom or an alkyl group with 1 to 5 carbon atoms, A ₁ ~A ₂ are each It is independently a hydrogen atom, or an alkyl group with 1 to 10 carbons, an alkenyl group with 2 to 10 carbons, or an alkynyl group with 2 to 10 carbons which may have a substituent). A liquid crystal alignment film, which is obtained from the liquid crystal alignment agent of any one of items 1 to 7 in the scope of the patent application. A liquid crystal display element, which is provided with a liquid crystal alignment film as claimed in item 8 of the scope of patent application. A transverse electric field drive type liquid crystal display element, which is provided with a liquid crystal alignment film as described in item 8 of the scope of patent application.