CN111868620B

CN111868620B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN111868620B
Application number: CN201980020161.8A
Authority: CN
Inventors: 别府功一朗; 须贺贵裕; 相马早纪
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2018-03-19
Filing date: 2019-03-18
Publication date: 2023-11-03
Anticipated expiration: 2039-03-18
Also published as: CN117148630A; JPWO2019181879A1; KR20200132908A; JP7334723B2; TW201947028A; WO2019181879A1; CN111868620A; KR102708816B1; TWI834646B

Abstract

Provided are a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element, which can obtain a liquid crystal aligning film having excellent voltage holding rate, rapid relaxation of accumulated charges, good liquid crystal alignment property, and good transparency. A liquid crystal aligning agent comprising the following component (A), component (B) and an organic solvent. Component (A): at least one polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a side chain type acrylic polymer exhibiting liquid crystallinity in a temperature range of 100 to 300 ℃, (B) component: a compound (Q) represented by the following formula (1) ¹ 、Q ² Is (Q1-1), etc., Q ¹ 、Q ² Any one of them is (Q1-1)), (Q1, Q2 are 0 or 1, R ¹ R is a hydrogen atom or the like ² 、R ³ R is a group having an epoxy moiety or the like ² 、R ³ Any of them is a group having an epoxy moiety. ).

Description

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

Technical Field

The present invention relates to a novel liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element using the same.

Background

Liquid crystal display devices are widely used as display portions for computers, mobile phones, smart phones, televisions, and the like. The liquid crystal display element includes, for example: a liquid crystal layer sandwiched between the element substrate and the color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling alignment of liquid crystal molecules of the liquid crystal layer, a Thin Film Transistor (TFT) for switching an electric signal supplied to the pixel electrode, and the like. As driving methods of liquid crystal molecules, a vertical electric field method such as a TN method and a VA method, and a lateral electric field method such as an IPS method and an FFS method are known. A lateral electric field system in which an electrode is formed only on one side of a substrate and an electric field is applied in a direction parallel to the substrate is known as a liquid crystal display element having a wider viewing angle characteristic and capable of realizing high-quality display, as compared with a conventional vertical electric field system in which a voltage is applied to electrodes formed on upper and lower substrates to drive liquid crystals.

In the liquid crystal cell of the transverse electric field system, although the viewing angle characteristics are excellent, since the electrode portions formed in the substrate are small, when the voltage holding ratio is low, a sufficient voltage is not applied to the liquid crystal, and the display contrast is lowered. In addition, when the stability of the alignment of the liquid crystal is small, the liquid crystal cannot return to the original state when the liquid crystal is driven for a long period of time, and the liquid crystal is important because the contrast is lowered and the afterimage is caused. Further, static electricity is likely to accumulate in the liquid crystal cell, and the application of positive and negative asymmetric voltages generated by driving causes accumulation of charges in the liquid crystal cell, and these accumulated charges affect display in the form of disorder of liquid crystal alignment and afterimage, which significantly reduces display quality of the liquid crystal element.

As a liquid crystal aligning agent which is excellent in voltage holding ratio and reduced in charge accumulation when used in such a liquid crystal display element of a transverse electric field system, patent document 1 discloses a liquid crystal aligning agent containing a specific diamine and an aliphatic tetracarboxylic acid derivative. As a method of shortening the time until the afterimage disappears, there have been proposed a method of using an alignment film having a low volume resistivity as in patent document 2 and an alignment film having a volume resistivity which is less likely to change due to a backlight of a liquid crystal display element as in patent document 3. However, as the performance of liquid crystal display devices increases, the characteristics required for liquid crystal alignment films become more and more stringent, and it is difficult for these conventional techniques to sufficiently satisfy all the required characteristics.

Prior art literature

Patent literature

Patent document 1: international publication (WO) 2004/021076 booklet

Patent document 2: international publication (WO) 2004/053583 booklet

Patent document 3: international publication (WO) 2013/008822 booklet

Disclosure of Invention

Problems to be solved by the invention

The invention provides a liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal display element, wherein the liquid crystal aligning agent can obtain a liquid crystal aligning film with excellent voltage holding rate, rapid relaxation of accumulated charges and good liquid crystal alignment property and transparency.

Solution for solving the problem

The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention.

The present invention provides a liquid crystal aligning agent, which is characterized by comprising the following component (A), component (B) and an organic solvent.

(A) The components are as follows: polymer

(B) The components are as follows: a compound represented by the following formula (1)

(wherein Q ¹ Q and Q ² Is one selected from the following (Q1-1) and single bond, Q ¹ Q and Q ² At least one of them is (Q1-1),

q1 and q2 are each independently 0 or 1,

R ¹ is a hydrogen atom or a monovalent organic group,

R ² r is R ³ Each independently is any one of a group having an epoxy moiety and a hydrogen atom, R ² R is R ³ At least one of them is a group having an epoxy moiety. )

ADVANTAGEOUS EFFECTS OF INVENTION

The liquid crystal aligning agent of the present application can provide a liquid crystal alignment film having excellent voltage holding ratio, rapid relaxation of accumulated charges, good liquid crystal alignment property and transparency, and a liquid crystal display element having excellent display characteristics.

The reason why the above problems can be solved by the present application has not been determined, and is considered to be approximately as follows. The structure of the compound represented by the formula (1) contained in the liquid crystal aligning agent of the present application has a conjugated structure. This can promote movement of charges in the liquid crystal alignment film, and promote relaxation of accumulated charges.

Detailed Description

Component (A)

The component (A) contained in the liquid crystal aligning agent of the present application is at least one polymer selected from the group consisting of polyimide precursors, imidized polymers of the polyimide precursors, and side chain acrylic polymers exhibiting liquid crystallinity in a predetermined temperature range.

< polyimide precursor >)

The polyimide precursor as the component (A) has a structural unit represented by the following formula (A1).

In the formula (A1), X ₁ An organic group of valence 4, Y ₁ An organic group having a valence of 2.

R ₁ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, A ₁ A is a ₂ Each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted, an alkenyl group having 2 to 10 carbon atoms which may be substituted, or an alkynyl group having 2 to 10 carbon atoms which may be substituted.

As R ₁ Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and the like. From the viewpoint of the easiness of imidization by heating, R ₁ Preferably a hydrogen atom or a methyl group.

X ₁ The structure of the organic group having a valence of 4 derived from the tetracarboxylic acid derivative is not particularly limited. In polyimide precursor, X ₁ More than 2 kinds may be mixed.

As X ₁ Specific examples of (B) include structures of the following formulas (X-1) to (X-44).

R in the above formula (X-1) ₈ ～R ₁₁ Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a phenyl group. R is R ₈ ～R ₁₁ In the case of a bulky structure, the liquid crystal alignment may be lowered, and therefore, a hydrogen atom, a methyl group, or an ethyl group is more preferable, and a hydrogen atom or a methyl group is particularly preferable.

As X ₁ From the viewpoint of availability of the monomer, the structure selected from the formulae (X-1) to (X-14) is preferable.

As a preferable ratio of the structure selected from the above formulae (X-1) to (X-14), X is ₁ The total amount is 20 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol% or more.

A ₁ A is a ₂ Each independently is a hydrogen atom, optionally substituted Alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms which may be substituted, or alkynyl group having 2 to 10 carbon atoms which may be substituted.

Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, t-butyl, hexyl, octyl, decyl, cyclopentyl, cyclohexyl, and dicyclohexyl groups.

Examples of the alkenyl group include those having 1 or more CH groups present in the above alkyl group ₂ -CH ₂ The structure is replaced by a ch=ch structure. Specifically, vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1, 3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl, cyclohexenyl and the like are exemplified.

As the alkynyl group, there may be mentioned 1 or more CH groups to be present in the above alkyl group ₂ -CH ₂ A group obtained by replacing the structure with a C.ident.C structure. Specifically, an ethynyl group, a 1-propynyl group, a 2-propynyl group, and the like are exemplified.

The alkyl group, alkenyl group, or alkynyl group may have a substituent, or may further have a ring structure formed by the substituent. The term "ring structure formed by substituents" means that substituents are bonded to each other or to a part of a parent skeleton to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organoxy group, an organosulfur group, an organosilyl group, an acyl group, an ester group, a thioester group, a phosphate group, an amide group, an alkyl group, an alkenyl group, an alkynyl group, and the like.

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

Examples of the aryl group as a substituent include phenyl groups. The aryl group may in turn be substituted with other substituents as previously described.

The organic oxy group as a substituent may show a structure represented by-O-R. The R groups may be the same or different, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and the like. These R's may in turn be substituted with the aforementioned substituents. Specific examples of the organic oxy group include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy and the like.

The organosulfur group as a substituent may show a structure represented by-S-R. Examples of the R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R's may in turn be substituted with the aforementioned substituents. Specific examples of the organosulfur group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group and the like.

The organosilyl group as a substituent may be represented by-Si- (R) ₃ The structure shown. The R groups may be the same or different, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and the like. These R's may in turn be substituted with the aforementioned substituents. Specific examples of the organic silyl group include trimethylsilyl group, triethylsilyl group, tripropylsilyl group, tributylsilyl group, tripentylsilyl group, trihexylsilyl group, pentyldimethylsilyl group, and hexyldimethylsilyl group.

The acyl group as a substituent may show a structure represented by-C (O) -R. Examples of the R include the aforementioned alkyl group, alkenyl group, aryl group, and the like. These R's may in turn be substituted with the aforementioned substituents. Specific examples of the acyl group include a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pentanoyl group, an isovaleryl group, and a benzoyl group.

The ester group as a substituent may show a structure represented by-C (O) O-R, or-OC (O) -R. Examples of the R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R's may in turn be substituted with the aforementioned substituents.

The thioester group as a substituent may show a structure represented by-C (S) O-R, or-OC (S) -R. Examples of the R include the aforementioned alkyl group, alkenyl group, alkynyl group, aryl group, and the like. These R's may in turn be substituted with the aforementioned substituents.

The phosphate group as a substituent may be represented by-OP (O) - (OR) ₂ The structure shown. The R groups may be the same or different, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and the like. These R may in turn be substituted by the aforementioned substituentsAnd (3) substitution.

The amide group as a substituent may be represented by-C (O) NH ₂ or-C (O) NHR, -NHC (O) R, -C (O) N (R) ₂ -NRC (O) R. The R groups may be the same or different, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and the like. These R's may in turn be substituted with the aforementioned substituents.

The aryl group as a substituent may be the same aryl group as the aforementioned aryl group. The aryl group may in turn be substituted with other substituents as previously described.

The alkyl group as a substituent may be the same as the aforementioned alkyl group. The alkyl group may in turn be substituted with other substituents as previously described.

The alkenyl group as a substituent may be the same alkenyl group as the aforementioned alkenyl group. The alkenyl group may in turn be substituted with other substituents as previously described.

The alkynyl group as a substituent may be the same as the aforementioned alkynyl group. The alkynyl group may in turn be substituted with other substituents as previously described.

In general, when a bulky structure is introduced, the reactivity of amino groups and the alignment of liquid crystals may be lowered, and thus a is the case ₁ A is a ₂ More preferably a hydrogen atom, or an alkyl group having 1 to 5 carbon atoms which may be substituted, and particularly preferably a hydrogen atom, a methyl group or an ethyl group.

Y ₁ The structure of the organic group having a valence of 2 derived from diamine is not particularly limited. As Y ₁ Specific examples of (B) include the following formulas (Y-1) to (Y-119).

In the formula (Y-109), m and n are integers of 1 to 11, and m+n is an integer of 2 to 12, respectively.

In the formula (Y-114), h is an integer of 1 to 3, and in the formulas (Y-111) and (Y-117), j is an integer of 0 to 3.

As Y ₁ From the viewpoints of the liquid crystal alignment property and pretilt angle of the obtained liquid crystal alignment film, at least one structure selected from the structures represented by the following formulas (5) and (6) is more preferable.

In the formula (5), R ₁₂ Is a single bond or a 2-valent organic group having 1 to 30 carbon atoms, R ₁₃ Is a hydrogen atom, a halogen atom or a 1-valent organic group having 1 to 30 carbon atoms, and a is an integer of 1 to 4. When a is 2 or more, R ₁₂ R is R ₁₃ May be the same as or different from each other.

In the formula (6), R ₁₄ Is a single bond, -O-, -S-, -NR ₁₅ -, an amide bond, an ester bond, a urea bond, or a 2-valent organic group having 1 to 40 carbon atoms, R ₁₅ Is a hydrogen atom or a methyl group.

Y represented by the formula (5) and the formula (6) ₁ Specific examples of (B) include the following structures in the above formulae (Y-1) to (Y-119).

Y of structure with high linearity ₁ Since the alignment property of the liquid crystal can be improved when the liquid crystal alignment film is formed, the formula (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), or (Y-118) is preferable.

Can improve the orientation of liquid crystalSex of the above Y ₁ The ratio of the structures of (C) is preferably Y ₁ The total amount is 20 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol% or more.

When the pretilt angle of the liquid crystal is to be increased in the production of the liquid crystal alignment film, Y is the ratio of ₁ The side chain preferably has a long-chain alkyl group, an aromatic ring, an aliphatic ring, a steroid skeleton, or a combination thereof. As such Y ₁ The formulae (Y-76) to (Y-97) are preferable. The above Y in the case of the intention to increase the pretilt angle ₁ The ratio of the structures of (C) is preferably Y ₁ The total amount is 1 to 30 mol%, more preferably 1 to 20 mol%.

In the case of using a polyimide precursor or polyimide having a photo-alignment side chain as the polymer of component (a), the polyimide precursor or polyimide preferably has a photo-reactive side chain as described below.

-R ⁶ -R ⁷ -R ⁸ -R ⁹ (c)

(in the formula (c), R ⁶ represents-CH ₂ -、-O-、-COO-、-OCO-、-NHCO-、-CONH-、-NH-、-CH ₂ O-、-N(CH ₃ )-、-CON(CH ₃ ) -, or-N (CH) ₃ )CO-。R ⁷ Represents a cyclic, unsubstituted or fluorine-substituted alkylene group having 1 to 20 carbon atoms (optional-CH of alkylene group) ₂ Can be-CF ₂ Or-ch=ch-substitution, or substitution with any of the groups listed below in a manner not adjacent to each other (as a group, is-O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, carbocycle, or heterocycle). R is R ⁸ represents-CH ₂ -、-O-、-COO-、-OCO-、-NHCO-、-NH-、-N(CH ₃ )-、-CON(CH ₃ )-、-N(CH ₃ ) CO-, carbocycle, or heterocycle. R is R ⁹ Represents vinylphenyl, -CR ¹⁰ ＝CH ₂ Base, -CR ¹⁰ (OH)-CH ₃ A group, a carbocycle, a heterocycle, or a structure represented by the formula R ¹⁰ Represents a hydrogen atom or a methyl group optionally substituted by a fluorine atom. )

In the production of the polyimide precursor, it is convenient to use a diamine obtained by replacing the side chain represented by the formula (c) as the diamine.

In addition, a polyimide precursor having a photo-alignment group in the main chain may also be used. In this case, it is convenient to use a diamine having a bond containing a photo-alignment group between amines represented by the following formula (2).

In the formula (2), X ¹ Is a single bond or an alkylene group having 1 to 5 carbon atoms, X ² is-OCO-CH=CH-or-CH=CH-COO-, X ³ Is a single bond, an alkylene group having 1 to 10 carbon atoms or a benzene ring having 2 valences, X ⁴ Is a single bond, -OCO-ch=ch-, or-ch=ch-COO-, X ⁵ Is a single bond or an alkylene group having 1 to 5 carbon atoms. Wherein the cinnamoyl group is more than 1.

The diamine represented by the formula (2) includes the following formulas (2-a) to (2-d).

Wherein X is a bonding group selected from a single bond or an ether (-O-), an ester (-COO-or OCO-) and an amide (-CONH-or NHCO-), Y is a single bond or an alkylene group having 1 to 5 carbon atoms, and Z is an alkylene group having 1 to 10 carbon atoms or a phenylene group. The bonding position of the amino group on the benzene ring and the position of the bonding group with respect to the central benzene ring are not particularly limited.

Specific examples of the diamine represented by the formula (2) include the following diamines.

The liquid crystal alignment film formed using the polyimide precursor such as the polyamic acid or the polyamic acid ester of the present invention, the polyimide or the liquid crystal alignment agent for the polyamide, which contains the diamine represented by the above formula (2) as a raw material, is reduced in the variation of the alignment property of the liquid crystal based on AC (alternating current) driving, for example, the variation of the alignment orientation of the liquid crystal. Therefore, the liquid crystal display element having the liquid crystal alignment film has stable liquid crystal alignment performance of the liquid crystal alignment film when AC driving is used, and thus, afterimages due to AC driving are less likely to occur. That is, the afterimage characteristics based on AC driving are exhibited very good effects.

The liquid crystal alignment film formed using the diamine represented by the above formula (2) is also excellent in liquid crystal alignment performance itself, and can be formed substantially free of alignment defects.

The polyimide precursor used in the present invention is obtained by reacting a diamine component with a tetracarboxylic acid derivative, and includes polyamic acid, polyamic acid ester, and the like.

< production of polyimide precursor (Polyamic acid) >)

The polyamic acid as a polyimide precursor used in the present invention is produced by the following method. Specifically, the tetracarboxylic dianhydride and the diamine can be synthesized by reacting them in the presence of an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃ for 30 minutes to 24 hours, preferably 1 to 12 hours.

The reaction of the diamine component with the tetracarboxylic acid component is usually carried out in an organic solvent. The organic solvent used in this case is not particularly limited as long as the polyimide precursor to be formed is dissolved. Specific examples of the organic solvent used in the reaction are given below, but the present invention is not limited to these examples. Examples thereof include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, gamma-butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and 1, 3-dimethyl-imidazolidinone.

In addition, when the polyimide precursor has high solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or an organic solvent represented by the following formulas [ D-1] to [ D-3] may be used.

[ D-1]]In (D) ¹ Represents an alkyl group having 1 to 3 carbon atoms, and the formula [ D-2 ]]In (D) ² Represents an alkyl group having 1 to 3 carbon atoms, and the formula [ D-3]]In (D) ³ Represents an alkyl group having 1 to 4 carbon atoms.

These organic solvents may be used alone or in combination. Further, even if the solvent is a solvent in which the polyimide precursor is not dissolved, the solvent may be used by mixing the solvent in such a range that the polyimide precursor to be produced is not deposited. Further, since moisture in the organic solvent may cause inhibition of polymerization reaction and further hydrolysis of the polyimide precursor to be produced, it is preferable to use a dehydrated and dried solvent for the organic solvent.

The concentration of the polyamic acid polymer in the reaction system is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, because precipitation of the polymer is less likely to occur and a high molecular weight body is easily obtained.

The polyamic acid obtained in the above-described manner can be recovered by pouring the reaction solution into a poor solvent while stirring the reaction solution sufficiently to precipitate a polymer. In addition, the precipitation may be performed a plurality of times, and the powder of the purified polyamic acid may be obtained by washing with a poor solvent and then drying at room temperature or by heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

< production of polyimide precursor (Polyamic acid ester) >)

The polyamic acid ester that is a polyimide precursor used in the present invention can be produced by the following method (1), (2) or (3).

(1) Case of producing from polyamic acid

The polyamic acid ester can be produced by esterifying the polyamic acid produced by the above-described operation. Specifically, the polyamide acid can be produced by reacting a polyamide acid with an esterifying agent in the presence of an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃ for 30 minutes to 24 hours, preferably 1 to 4 hours.

The esterification agent is preferably one that can be easily removed by purification, and examples thereof include: n, N-dimethylformamide dimethylacetal, N-dimethylformamide diethylacetal, N-dimethylformamide dipropylacetal, N-dimethylformamide di-neopentyl-butylacetal, N-dimethylformamide di-t-butylacetal, 1-methyl-3-p-tolyltriazine, 1-ethyl-3-p-tolyltriazine, 1-propyl-3-p-tolyltriazine, 4- (4, 6-dimethoxy-1, 3, 5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The amount of the esterifying agent to be added is preferably 2 to 6 molar equivalents relative to 1 mole of the repeating unit of the polyamic acid.

Examples of the organic solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, gamma-butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and 1, 3-dimethyl-imidazolidinone. In the case where the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or an organic solvent represented by the above formulae [ D-1] to [ D-3] may be used.

These organic solvents may be used alone or in combination. Further, even a solvent in which the polyimide precursor is not dissolved may be used by mixing it with the solvent in such a range that the polyimide precursor to be produced is not deposited. Further, since moisture in the organic solvent may cause inhibition of polymerization reaction and further hydrolysis of the polyimide precursor to be produced, it is preferable to use a dehydrated and dried solvent for the organic solvent.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or gamma-butyrolactone from the viewpoint of solubility of the polymer, and these may be used in a mixture of 1 or 2 or more. The concentration at the time of production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer is less likely to occur and a high molecular weight body is easily obtained.

(2) In the case of production by reaction of tetracarboxylic acid diester dichloride with diamine

The polyamic acid ester can be made from a tetracarboxylic acid diester dichloride and a diamine. Specifically, the catalyst can be produced by reacting a tetracarboxylic acid diester dichloride with a diamine in the presence of a base and an organic solvent at-20 to 150 ℃, preferably 0 to 50 ℃ for 30 minutes to 24 hours, preferably 1 to 4 hours.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, and pyridine is preferable in order to allow the reaction to proceed gently. The amount of the base to be added is preferably 2 to 4 times by mol based on the amount of the tetracarboxylic acid diester dichloride, from the viewpoint of easy removal and easy production of a high molecular weight body.

The organic solvent is preferably N-methyl-2-pyrrolidone or γ -butyrolactone from the viewpoint of solubility of the monomer and polymer, and 1 or 2 or more of these may be used in combination.

The concentration of the polymer at the time of production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer is less likely to occur and a high molecular weight body is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the organic solvent used in the production of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent the mixing of outside air in a nitrogen atmosphere.

(3) In the case of preparation from a tetracarboxylic diester and a diamine

The polyamic acid ester can be produced by polycondensing a tetracarboxylic acid diester and a diamine. Specifically, the catalyst can be produced by reacting a tetracarboxylic acid diester with a diamine in the presence of a condensing agent, a base, and an organic solvent at 0 to 150 ℃, preferably 0 to 100 ℃ for 30 minutes to 24 hours, preferably 3 to 15 hours.

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N ' -carbonyldiimidazole, dimethoxy-1, 3, 5-triazinylmethyl morpholinium, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium hexafluorophosphate, diphenyl (2, 3-dihydro-2-thio-3-benzoxazolyl) phosphonate and the like can be used. The amount of the condensing agent to be added is preferably 2 to 3 times by mol based on the tetracarboxylic diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be added is preferably 2 to 4 times by mol based on the diamine component, from the viewpoint of easy removal and easy obtaining of a high molecular weight body.

In addition, in the above reaction, by adding a lewis acid as an additive, the reaction proceeds efficiently. Lithium halides such as lithium chloride and lithium bromide are preferable as the lewis acid. The amount of the lewis acid to be added is preferably 0 to 1.0 times by mol based on the diamine component.

Among the above 3 methods for producing polyamide acid esters, the production method of the above (1) or (2) is particularly preferred in order to obtain polyamide acid esters having a high molecular weight.

The solution of the polyamic acid ester obtained in the above-described manner can be injected into a poor solvent with sufficient stirring, whereby a polymer can be precipitated. The precipitation may be performed a plurality of times, and the powder of the purified polyamic acid ester may be obtained by washing with a poor solvent and then drying at room temperature or by heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, and the like.

< polyimide >

The polyimide used in the present invention (imidized polymer in component (a)) can be produced by imidizing the polyamic acid ester or polyamic acid described above.

In the case of producing polyimide from polyamic acid, chemical imidization is relatively simple in which a catalyst is added to a solution of the polyamic acid obtained by the reaction between a diamine component and tetracarboxylic dianhydride. The chemical imidization is preferable because the imidization is carried out at a relatively low temperature and the molecular weight of the polymer is less likely to be lowered during the imidization.

Chemical imidization can be performed by stirring the polyamic acid to be imidized in the presence of a basic catalyst and an acid anhydride in an organic solvent. As the organic solvent, the organic solvents used in the polymerization reaction described above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a moderate basicity for the reaction to proceed. Further, among them, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like are preferable because purification after completion of the reaction is easy when acetic anhydride is used.

The imidization reaction is carried out at a temperature of-20 to 140 ℃, preferably 0 to 100 ℃, and the reaction time may be 0.5 to 100 hours, preferably 1 to 80 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times, that of the amic acid, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times, that of the amic acid. The imidization rate of the obtained polymer can be controlled by adjusting the catalyst amount, temperature and reaction time.

Since an added catalyst or the like remains in the solution after the imidization of the polyamic acid ester or the polyamic acid, the imidized polymer obtained is preferably recovered by the means described below, and redissolved by an organic solvent, to be used as the component (a) of the liquid crystal aligning agent of the present invention.

The polyimide solution obtained in the above-described manner can be injected into a poor solvent while being sufficiently stirred, whereby a polymer can be precipitated. The polyimide may be precipitated a plurality of times, washed with a poor solvent, and then dried at room temperature or by heating to obtain a purified polyimide powder.

The poor 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.

Side chain type acrylic polymer

The side chain type acrylic polymer which is one of the embodiments of the component (a) of the present invention exhibits liquid crystallinity in a predetermined temperature range and has photosensitivity.

The side chain type acrylic polymer preferably reacts with light in a wavelength range of 200 to 450nm and exhibits liquid crystallinity in a temperature range of 100 to 300 ℃.

The side chain type acrylic polymer preferably has a photosensitive side chain that reacts with light in a wavelength range of preferably 200 to 450nm, more preferably 250 to 400 nm.

The side chain type acrylic polymer preferably has a mesogen group for exhibiting liquid crystallinity in a temperature range of preferably 100 to 350 ℃, more preferably 120 to 300 ℃.

The side chain type acrylic polymer has a side chain having photosensitivity bonded to the main chain, and can undergo a crosslinking reaction, an isomerization reaction, or photofries rearrangement in response to light. The side chain having photosensitivity has a structure that generates a crosslinking reaction by sensing light, or a photofries rearrangement, and more preferably generates a crosslinking reaction. In this case, even when exposed to external stress such as heat, the orientation control capability can be stably maintained for a long period of time.

The structure of the side-chain type acrylic polymer film capable of exhibiting liquid crystallinity is not particularly limited as long as it satisfies such characteristics, and a liquid mesogen component having rigidity in the side-chain structure is preferable. In this case, when the side chain type acrylic polymer is formed into a liquid crystal alignment film, stable liquid crystal alignment can be obtained.

As the structure of the side chain type acrylic polymer, for example, the following structure is preferable: the side chain has a structure of a mesogen component such as biphenyl, terphenyl, phenylcyclohexyl, phenylbenzoate, azo phenyl and the like, and a photosensitive group bonded to the front end portion and subjected to a crosslinking reaction and an isomerization reaction by induction light; or a main chain and a side chain bonded thereto, and the side chain has a structure of a phenyl benzoate group which becomes a mesogen component and undergoes a photofries rearrangement reaction.

As a specific example of the structure of the side chain type acrylic polymer, the following structure is preferable: has a structure comprising a main chain derived from a radical polymerizable group of at least one compound selected from the group consisting of hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl, maleimide, and norbornene, and a side chain composed of at least one of the following formulas (i) to (v).

Wherein Ar is ₁ Represents a substituent having a valence of 2, which is obtained by removing 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring.

Ar ₂ Ar and Ar ₃ Each independently represents a substituent having a valence of 2, which is obtained by removing 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring. One of q1 and q2 is 1 and the other is 0.

Ar ₄ Ar and Ar ₅ Each independently represents a substituent having a valence of 2, which is obtained by removing 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring. Y is Y ₁ -Y ₂ represents-CH=CH-, -CH=N-, -N=CH-, or-C≡C-.

S ₁ 、S ₂ S and S ₃ Each independently represents a single bond, a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a phenylene group or a biphenylene group, or represents 1 or 2 or more bonds selected from the group consisting of a single bond, an ether bond, an ester bond, an amide bond, a urea bond, a urethane bond, an amino bond, a carbonyl group or a combination thereof, or represents a structure in which 2 or more to 10 sites selected from the group consisting of a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a phenylene group, a biphenylene group or a combination thereof are bonded via the above bonds. The substituent having a valence of 2 may be a plurality of substituents each bonded via the bond And (3) forming the structure.

R ₁₁ Represents a hydrogen atom, a hydroxyl group, a mercapto group, an amino group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 8 carbon atoms or a dialkylamino group having 2 to 16 carbon atoms.

The benzene ring and/or naphthalene ring is optionally substituted with 1 or more groups selected from the group consisting of a halogen atom, a cyano group, a nitro group, a carboxyl group and an alkoxycarbonyl group having 2 to 11 carbon atoms, which are the same or different. In this case, the alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, may have a structure in which these groups are combined, or may be substituted with a halogen atom.

The side chain type acrylic polymer of the present invention preferably contains a liquid crystalline side chain.

The mesogenic group of the side chain may be a group having a mesogenic structure such as biphenyl or phenylbenzoate, or may be a group having a mesogenic structure such as benzoic acid in which the side chains are hydrogen bonded to each other. The mesogenic group of the side chain is preferably of the following structure.

Side chain type acrylic polymer

The side chain type acrylic polymer of the present invention can be obtained by polymerizing the photoreactive side chain monomer having a photosensitive side chain and the liquid crystalline side chain monomer.

[ photoreactive side chain monomer ]

The photoreactive side chain monomer is a monomer capable of forming a polymer having a photosensitive side chain at a side chain portion of the polymer when the polymer is formed.

The photoreactive group having a side chain is preferably a structure represented by the above formulas (i) to (v).

More specific examples of the photoreactive side chain monomer are preferably those having a radical polymerizable group of at least one compound selected from the group consisting of hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl compounds, maleimide, and norbornene, and a photosensitive side chain composed of at least one compound selected from the group consisting of the above formulas (i) to (v).

[ liquid Crystal side chain monomer ]

The liquid crystalline side chain monomer is a monomer in which a polymer derived from the monomer exhibits liquid crystallinity and the polymer can form a mesogen group at a side chain portion.

More specific examples of the liquid crystalline side chain monomer are preferably a structure comprising: a radical polymerizable group of at least one compound selected from the group consisting of hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α -methylene- γ -butyrolactone, styrene, vinyl compounds, maleimide, and norbornene; and a liquid crystalline side chain having at least one selected from the group consisting of the aforementioned mesogenic groups.

The side chain type acrylic polymer of the present invention can be obtained by polymerization of the above-mentioned photoreactive side chain monomer exhibiting liquid crystallinity. Further, the polymer may be obtained by copolymerizing a photoreactive side chain monomer that does not exhibit liquid crystallinity with a liquid crystalline side chain monomer, or copolymerizing a photoreactive side chain monomer that exhibits liquid crystallinity with a liquid crystalline side chain monomer. Further, the polymer may be copolymerized with other monomers within a range that does not impair the expressibility of liquid crystallinity.

Examples of the other monomer include commercially available monomers capable of undergoing radical polymerization.

Specific examples of the other monomer include unsaturated carboxylic acids, acrylic esters, methacrylic esters, maleimides, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, and the like.

Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and the like.

Examples of the acrylic acid ester include: methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl methyl acrylate, phenyl acrylate, 2-trifluoroethyl acrylate, t-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, 8-ethyl-8-tricyclodecyl acrylate, and the like.

Examples of the methacrylate include: methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, phenyl methacrylate, 2-trifluoroethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-tricyclodecyl methacrylate, and the like. Furthermore, (meth) acrylate compounds having a cyclic ether group such as glycidyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate and (3-ethyl-3-oxetanyl) methyl (meth) acrylate can be used.

Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

Examples of the styrene compound include styrene, methyl styrene, chlorostyrene, and bromostyrene.

Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

The method for producing the side chain type acrylic polymer of the present invention is not particularly limited, and a general method used in industry can be used. Specifically, the polymer can be produced by cationic polymerization, radical polymerization, anionic polymerization, or the like using a vinyl group of a liquid crystalline side chain monomer or a photoreactive side chain monomer. Among them, radical polymerization is particularly preferred from the viewpoint of easiness of reaction control and the like.

The polymerization initiator for radical polymerization may be any known radical polymerization initiator such as AIBN (azobisisobutyronitrile) or any known compound such as a reversible addition-fragmentation chain transfer (RAFT) polymerization reagent.

The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a bulk polymerization method, a solution polymerization method, and the like can be used.

The organic solvent used in the polymerization reaction of the side chain type acrylic polymer is not particularly limited as long as the polymer to be produced is dissolved. Specific examples thereof are listed below.

There may be mentioned: n, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, gamma-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethylpentanone, methylnonyl ketone, methylethyl ketone, methylisopentyl ketone, methylisopropyl ketone, methylcellosolve, ethylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-t-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethylisobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, tetrahydrofuran, N-hexane, N-pentane, N-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, N-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, and the like.

These organic solvents may be used alone or in combination. Further, even if the solvent does not dissolve the polymer to be produced, the solvent may be mixed with the organic solvent so far as the polymer to be produced does not precipitate.

In addition, in the radical polymerization, oxygen in the organic solvent becomes a cause of inhibiting the polymerization reaction, and therefore, it is preferable to use an organic solvent which is deaerated to the extent possible.

The polymerization temperature in the radical polymerization may be any temperature selected from 30 to 150℃and preferably in the range of 50 to 100 ℃.

The reaction may be carried out at any concentration, but when the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and when the concentration is too high, the viscosity of the reaction solution becomes too high, and it is difficult to uniformly stir the reaction solution, so that the monomer concentration is preferably 1 to 50 mass%, more preferably 5 to 30 mass%. Preferably, the reaction is carried out at a high concentration at the initial stage and then an organic solvent is added.

In the radical polymerization reaction, when the ratio of the radical polymerization initiator is large relative to the monomer, the molecular weight of the obtained polymer becomes small, and when the ratio of the radical polymerization initiator is small relative to the monomer, the molecular weight of the obtained polymer becomes large, and therefore, the ratio of the radical polymerization initiator is preferably 0.05 to 15 mol%, more preferably 0.1 to 10 mol% relative to the polymerized monomer. In addition, various monomer components, organic solvents, radical polymerization initiators, and the like may be added during polymerization.

When the polymer produced is recovered from the reaction solution containing the side chain type acrylic polymer obtained by the polymerization reaction, the reaction solution is preferably poured into a poor solvent to precipitate the polymer produced. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by being put into the poor solvent is preferably recovered by filtration and then dried at normal temperature or under reduced pressure. In addition, when the polymer recovered by precipitation is repeatedly dissolved in an organic solvent and reprecipitated and recovered 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent used in the reprecipitation include alcohols, ketones, ethers, and hydrocarbons, and when 3 or more of these poor solvents are used, the purification efficiency is further improved, which is preferable.

The molecular weight of the side chain type acrylic polymer of the present invention is preferably 2,000 to 500,000, more preferably 5,000 ～ 100,000, as measured by GPC (gel permeation chromatography ) in consideration of the strength of the resulting coating film, workability in forming the coating film, and uniformity of the coating film.

The content of the polymer of the component (a) in the liquid crystal aligning agent of the present invention may be appropriately changed depending on the setting of the thickness of the coating film to be formed, and is preferably 1% by weight or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10% by weight or less from the viewpoint of the storage stability of the solution, and among these, 3 to 7% by weight is preferable.

Component (B)

The component (B) contained in the liquid crystal aligning agent of the present invention is a compound represented by the following formula (1).

(wherein Q ¹ Q and Q ² Is one selected from the following formula (Q1-1) and a single bond, Q ¹ Q and Q ² At least one of them is represented by the formula (Q1-1). q1 and q2 are each independently 0 or 1.R is R ² R is R ³ Each independently is any one of a group having an epoxy moiety and a hydrogen atom, R ² R is R ³ At least one of them is a group having an epoxy moiety. )

(in the formula (Q1-1), R ¹ Is a hydrogen atom, or a monovalent organic group. R is R ¹ More preferably, the monovalent organic group is a methyl group, a phenyl group, a group having an epoxy moiety, or a thermally decomposable leaving group.

The thermally decomposable leaving group refers to a substituent which is released by heating and is replaced with a hydrogen atom. The thermally decomposable leaving group is not particularly limited as long as it is a protecting group for an amino group, and its structure is a functional group that is replaced with a hydrogen atom by heat. The protecting group D is preferably a protecting group which does not separate at room temperature, preferably a protecting group which separates under the action of heat at 80 ℃ or higher, and more preferably a protecting group which separates under the action of heat at 100 ℃ or higher, from the viewpoint of storage stability of the liquid crystal aligning agent. D is particularly preferably t-butoxycarbonyl or 9-fluorenylmethoxycarbonyl from the point of view of the detachment temperature.

As R ¹ 、R ² R is R ³ Examples of the groups having an epoxy moiety in the definition of (a) include glycidyl groups and 3, 4-epoxycyclohexyl groups, and glycidyl groups are preferable from the viewpoint of ease of synthesis.

Preferable examples of the compound represented by the component (B) include the following compounds (B-1) to (B-6).

(B-1): in the above formula (1), Q1 and Q2 are 0, Q ¹ Is (Q1-1), R ² R is R ³ A compound having an epoxy group,

(B-2): in the above formula (1), Q1 and Q2 are 0, Q ¹ Is (Q1-1), R ² Is a hydrogen atom, R ³ A compound having an epoxy group,

(B-3): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is a single bond or (Q1-1), Q ² Is (Q1-1), R ² R is R ³ A compound having an epoxy group,

(B-4): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is a single bond or (Q1-1), Q ² Is (Q1-1), R ² Is a hydrogen atom, R ³ A compound which is a group having an epoxy group.

(B-5): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is (Q1-1), Q ² Is a single bond, R ² R is R ³ A compound having an epoxy group,

(B-6): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is (Q1-1), Q ² Is a single bond, R ² Is a hydrogen atom, R ³ A compound which is a group having an epoxy group.

Among the above, preferable components (B) include, for example, compounds represented by any of the following formulas B-1-1 to B-5-1.

The compound of the component (B) can be obtained by treating the obtained addition reaction product with a base to cause a cyclization reaction after reacting a diamine represented by the following formula (0) with epihalohydrin.

As the diamine represented by the formula (0), a known diamine can be used.

R in the production formula (1) ² R is R ³ When both are compounds having a group having an epoxy moiety, the epihalohydrin may be used in an amount of 4 equivalents or more, preferably 8 equivalents or more, based on the diamine represented by the formula (0), and then the resulting mixture may be treated with a base. Wherein R is manufactured ¹ In the case of a compound having a group having an epoxy moiety, a epihalohydrin may be used in a different amount. R is to be produced ² R is R ³ When one of the two is a compound having an epoxy moiety and the other is a hydrogen atom, 2 to 2.2 equivalents of epihalohydrin to the diamine represented by the formula (0) may be used, and the treatment with a base may be performed.

(B) If the component is too large, the liquid crystal alignment is affected, and if it is too small, the effect of the present invention is not sufficiently obtained. Therefore, the content of the component (B) in the liquid crystal aligning agent is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, with respect to the component (a) (100% by mass).

< liquid Crystal alignment agent >)

The liquid crystal aligning agent used in the present invention has a form of a solution of at least one polymer selected from the group consisting of the polyimide precursor of the component (a) and the imidized polymer of the polyimide precursor (hereinafter referred to as a specific structure polymer) and the compound of the component (B) dissolved in an organic solvent. The molecular weight of the polymer of specific structure is preferably 2,000 ～ 500,000, more preferably 5,000 ～ 300,000, and further preferably 10,000 ～ 100,000 in terms of weight average molecular weight. The number average molecular weight is preferably 1,000 ～ 250,000, more preferably 2,500 ～ 150,000, and further preferably 5,000 to 50,000.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention may be suitably changed according to the setting of the thickness of the coating film to be formed, and is preferably 1% by weight or more in terms of forming a uniform and defect-free coating film, and is preferably 10% by weight or less in terms of storage stability of the solution.

The organic solvent (good solvent) contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as it is a solvent that uniformly dissolves the polymer of a specific structure.

Examples include: n, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, gamma-butyrolactone, 1, 3-dimethyl-imidazolidinone, methylethylketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and the like.

Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and gamma-butyrolactone are preferably used.

Further, when the polymer of the present invention has high solubility in a solvent, it is preferable to use a solvent represented by the above-mentioned formulas [ D-1] to [ D-3 ].

The good solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99 mass% of the total solvent contained in the liquid crystal aligning agent. Of these, 20 to 90 mass% is preferable. More preferably 30 to 80 mass%.

The liquid crystal aligning agent of the present invention may be used as a solvent (also referred to as a poor solvent) for improving the film-coating property and surface smoothness of the liquid crystal alignment film when the liquid crystal aligning agent is applied. Specific examples of the poor solvent are listed below, but the present invention is not limited to these examples.

Examples include: ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-amyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1, 2-ethanediol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butandiol, 1, 3-butandiol 1, 4-butane diol, 2, 3-butane diol, 1, 5-pentane diol, 2-methyl-2, 4-pentane diol, 2-ethyl-1, 3-hexane diol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1, 2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 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, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, 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 acetate, 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 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, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, or a solvent represented by the aforementioned formula [ D-1] to formula [ D-3], and the like.

Among them, 1-hexanol, cyclohexanol, 1, 2-ethanediol, 1, 2-propane diol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether are preferably used.

These poor solvents are preferably 1 to 80% by mass of the total solvent contained in the liquid crystal aligning agent. Of these, 10 to 80 mass% is preferable. More preferably 20 to 70 mass%.

In addition to the above-mentioned materials, the liquid crystal aligning agent of the present invention may be added with a polymer other than the polymer described in the present invention, a dielectric or conductive material for changing the dielectric constant, conductivity, etc. of the liquid crystal alignment film, a silane coupling agent for improving the adhesion between the liquid crystal alignment film and a substrate, a crosslinkable compound for improving the hardness and the density of the film when the liquid crystal alignment film is formed, and an imidization accelerator for efficiently performing imidization by heating the polyimide precursor when the film is fired.

< liquid Crystal alignment film >)

The liquid crystal alignment film of the present invention is obtained by applying the liquid crystal alignment agent to a substrate, drying the substrate, and baking the substrate. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and plastic substrates such as a glass substrate, a silicon nitride substrate, an acryl substrate, a polycarbonate substrate, and the like can be used, and the use of a substrate having an ITO electrode or the like formed thereon for driving a liquid crystal is preferable from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque body such as a silicon wafer may be used if the substrate is a single-sided substrate, and a material reflecting light such as aluminum may be used for the electrode.

Examples of the method for applying the liquid crystal aligning agent of the present invention include spin coating, printing, and ink jet. The drying and firing steps after the application of the liquid crystal aligning agent of the present invention may be carried out at any temperature and for any time. In general, in order to sufficiently remove the organic solvent contained therein, the mixture is dried at 50 to 120℃for 1 to 10 minutes and then fired at 150 to 300℃for 5 to 120 minutes. The thickness of the coating film after firing is not particularly limited, and if it is too thin, the reliability of the liquid crystal display element may be lowered, and thus it is 5 to 300nm, preferably 10 to 200nm.

Examples of the method for aligning the obtained liquid crystal alignment film include rubbing method and photo-alignment treatment method.

The friction treatment may be performed using existing friction devices. The material of the friction cloth in this case may be cotton, nylon, rayon, or the like. As conditions for the friction treatment, conditions of a rotation speed of 300 to 2000rpm, a transport speed of 5 to 100mm/s, and a press-in amount of 0.1 to 1.0mm are generally used. Thereafter, residues generated by friction are removed by ultrasonic cleaning using pure water, alcohol, or the like.

Specific examples of the photo-alignment treatment method include the following methods: the surface of the coating film is irradiated with radiation deflected in a predetermined direction, and if necessary, is subjected to a heat treatment at a temperature of 150 to 250 ℃ to impart liquid crystal aligning ability. As the radiation, ultraviolet rays and visible rays having a wavelength of 100 to 800nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400nm are preferable, and ultraviolet rays having a wavelength of 200 to 400nm are particularly preferable. In order to improve the liquid crystal alignment, the coated substrate may be irradiated with radiation while being heated at 50 to 250 ℃. The irradiation amount of the above-mentioned radiation is preferably 1 to 10,000mJ/cm ² Particularly preferably 100 to 5,000mJ/cm ² . The liquid crystal alignment film thus produced can stably align liquid crystal molecules in a predetermined direction.

The higher the extinction ratio of the polarized ultraviolet light, the higher the anisotropy can be imparted, and thus is preferable. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10:1 or more, more preferably 20: more than 1.

The film irradiated with the polarized radiation in the above may then be subjected to a contact treatment with a solvent containing at least 1 selected from water and an organic solvent.

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

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

In the present invention, the contact treatment of the film irradiated with the polarized radiation with the solution containing the organic solvent is performed by such a treatment that the film is suitably and sufficiently contacted with the liquid, such as a dipping treatment or a spraying (spark) treatment. Among them, a method of immersing the film in a solution containing an organic solvent is preferable, and a method of immersing the film in the solution is preferable for 10 seconds to 1 hour, and more preferable for 1 to 30 minutes. The contact treatment may be carried out at normal temperature or by heating, preferably at 10 to 80 ℃, more preferably at 20 to 50 ℃. Further, means for improving contact such as ultrasonic waves may be applied as needed.

After the above-mentioned contact treatment, in order to remove the organic solvent in the used solution, either one or both of washing (rinsing) and drying with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, and the like may be performed.

Further, the film subjected to the solvent-based contact treatment in the above may be heated at 150 ℃ or higher for drying of the solvent and reorientation of the molecular chains in the film.

The heating temperature is preferably 150 to 300 ℃. The higher the temperature is, the more the molecular chains are promoted to be reoriented, but if the temperature is too high, there is a concern that the molecular chains are decomposed. Therefore, the heating temperature is more preferably 180 to 250 ℃, and particularly preferably 200 to 230 ℃.

If the heating time is too short, there is a possibility that the effect of reorientation of the molecular chains cannot be obtained, and if it is too long, there is a possibility that the molecular chains are decomposed, so that it is 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 characterized by comprising a liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film.

The liquid crystal display element of the present invention is produced by a known method after obtaining a substrate with a liquid crystal alignment film from the liquid crystal alignment agent of the present invention by the above-mentioned method for producing a liquid crystal alignment film, and then a liquid crystal cell is produced using the liquid crystal cell.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described. The liquid crystal display element may be an active matrix structure in which switching elements such as TFTs (Thin Film Transistor and thin film transistors) are provided in each pixel portion constituting an image display.

First, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode (segment electrode) is provided on the other substrate. These electrodes may be patterned in such a way that a desired image can be displayed, for example, using ITO electrodes. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film may be formed of, for example, siO by a sol-gel method ₂ -TiO ₂ A film is formed.

Next, the liquid crystal alignment film of the present invention is formed on each substrate. Next, one substrate is stacked on the other substrate so that the alignment film faces face each other, and the peripheries are bonded with a sealing material. In order to control the substrate gap, a spacer is usually mixed in advance in the sealing material. In addition, it is preferable that spacers for controlling the substrate gap are also dispersed in advance in the surface portion where the sealing material is not provided. An opening portion capable of being filled with liquid crystal from the outside is provided in advance in a part of the sealing material.

Then, a liquid crystal material was injected into a space surrounded by 2 substrates and the sealing material through an opening provided in the sealing material. Then, the opening is sealed with an adhesive. The injection may be performed by vacuum injection or by using capillary phenomenon in the atmosphere. Next, a polarizing plate is disposed. Specifically, a pair of polarizing plates are bonded to the surface of the 2 substrates opposite to the liquid crystal layer. Through the above steps, the liquid crystal display element of the present invention is obtained.

In the present invention, as the sealant, 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, or an acetyl group, which is cured by ultraviolet irradiation and heating, can be used. It is particularly preferable to use a cured resin having two reactive groups of an epoxy group and a (meth) acryl group.

The sealant of the present invention may contain an inorganic filler in order to improve adhesion and moisture resistance. The usable inorganic filler is not particularly limited, and specific examples thereof include: spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, 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, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, and the like, preferably spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, aluminum hydroxide, calcium silicate, aluminum silicate, and the like. The inorganic filler may be used in a mixture of 2 or more kinds.

Examples

The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds have the following meanings.

NMP: n-methyl-2-pyrrolidone, BCS: butyl cellosolve

THF: tetrahydrofuran (THF)

AIBN:2,2' -azobisisobutyronitrile

( ¹ Determination of H-NMR

The device comprises: varian NMR system 400NB (400 MHz) (manufactured by Varian Co., ltd.), and JMTC-500/54/SS (500 MHz) (manufactured by JEOL Co., ltd.)

Measuring solvent: CDCl ₃ (deuterated chloroform), DMSO-d ₆ (deuterated dimethyl sulfoxide)

Reference substance: TMS (tetramethylsilane) (δ:0.0ppm， ¹ h) CDCl ₃ (δ：77.0ppm， ¹³ C)

< Synthesis of additive E1 >

To toluene (25 g) and pure water (2.5 g) were added epichlorohydrin (52.1 g) and 4,4' -diamino-N-methyldiphenylamine (10.0 g, 46.9 mmol), and the mixture was stirred at 80℃for 4 hours. After cooling to room temperature, tetrabutylammonium bisulfate (0.48 g) and 48% aqueous sodium hydroxide solution (23.5 g) were added, and the mixture was stirred at 35℃for 3 hours and at room temperature for 16 hours. Pure water (50 g) was added thereto, and the oil layer was washed with pure water (50 g), dehydrated with magnesium sulfate, and the filtrate was concentrated to obtain a crude product. After the crude was dissolved in toluene (150 g), filtration was performed using a tung mountain funnel with a silica gel (20 g) laid on the filter surface. After toluene (50 g) was further circulated, all the filtrate was concentrated to obtain compound [ E1] (yield: 13.2g, yield: 64%, brown viscous body).

1H-NMR(400MHz,DMSO-d6,δppm)：6.78-6.73(m,8H),3.59(t,4H,J＝16Hz),3.38-3.26(m,4H),3.13-3.04(m,7H),2.75-2.71(m,4H),2.58-2.55(m,4H).

< Synthesis of additive E2 >

To toluene (25 g) and pure water (2.5 g) were added epichlorohydrin (55.4 g) and 4,4' -diaminodiphenyl ether (10.0 g, 49.9 mmol), and the mixture was stirred at 80℃for 23 hours. After cooling to room temperature, tetrabutylammonium bisulfate (0.51 g) and 48% aqueous sodium hydroxide solution (25.0 g) were added and stirred at 35℃for 5 hours. Pure water (50 g) was added thereto, and the oil layer was washed with pure water (50 g), dehydrated with magnesium sulfate, and the filtrate was concentrated to obtain a crude product. After the crude was dissolved in toluene (150 g), filtration was performed using a tung mountain funnel with a silica gel (20 g) laid on the filter surface. After toluene (50 g) was further circulated, all the filtrate was concentrated to obtain compound [ E2] (yield: 15.3g, yield: 72%, orange viscous body).

1H-NMR(400MHz,DMSO-d6,δppm)：6.84-6.80(m,8H),3.64(t,4H,J＝16Hz),3.40-3.28(m,4H),3.14-3.08(m,4H),2.76-2.72(m,4H),2.59-2.56(m,4H).

< viscosity >

In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Tokyo Co., ltd.) in a sample size of 1.1mL, a conical rotor TE-1 (1 DEG 34', R24) and a temperature of 25 ℃.

Synthesis example 1

To a 5L four-necked flask equipped with a stirrer and a nitrogen inlet tube, 57.3g (200 mmol) of DA-1 was weighed, and 1147g of NMP was added thereto, followed by stirring and dissolution with nitrogen. While stirring the diamine solution under water cooling, 29.4g (150 mmol) of CA-1 was added, 191g of NMP was added, and the mixture was stirred under nitrogen at 23℃for 1 hour. Next, 119.3g (400 mmol) of DA-2 and 60.1g (400 mmol) of DA-3 were weighed, and 1721g of NMP was added thereto, followed by stirring under nitrogen to dissolve the mixture. While stirring the diamine solution under water cooling, 158.8g (810 mmol) of CA-1 was added, 765g of NMP was added, and the mixture was stirred at 23℃for 6 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 180 mPas).

Synthesis example 2

MA1 (5.3 g) and MA2 (19.6 g) were dissolved in THF (102.6 g), and deaerated by a diaphragm pump, and then AIBN (0.39 g) was added thereto to deaerate again. Thereafter, the reaction was carried out at 60℃for 8 hours to obtain a polymer solution of methacrylic acid ester. The polymer solution was added dropwise to methanol (600 ml), and the resulting precipitate was filtered. The precipitate was washed with methanol and dried under reduced pressure in an oven at 40℃to obtain methacrylate polymer powder MP1.

Example 1 and comparative examples 1 and 2

The polyamic acid solution obtained in synthesis example 1 was stirred while adding a solvent and an additive so that the composition of the obtained liquid crystal aligning agent became the composition shown in table 1, and further stirred at room temperature for 2 hours, thereby obtaining a liquid crystal aligning agent.

TABLE 1

	Polymer 1	Additive 2	Solvent ratio 3
				Example 1	PAA-A1(100)	E1(3)	NMP(70)，BCS(25)
Comparative example 1	PAA-A1(100)	-	NMP(70)，BCS(25)
				Comparative example 2	PAA-A1(100)	E2(3)	NMP(70)，BCS(25)

1: the content (parts by weight) of each polymer per 100 parts by weight of the total polymers in the liquid crystal aligning agent is shown.

2: the content (parts by weight) of each additive per 100 parts by weight of the total polymer in the liquid crystal aligning agent is shown.

3: the content (parts by weight) of each solvent is shown in terms of 100 parts by weight of the liquid crystal aligning agent.

Example 2 and comparative examples 3 and 4

NMP was added to the methacrylate powder obtained in Synthesis example 2, and stirred for 30 minutes to obtain a methacrylate polymer solution. The liquid crystal aligning agent was obtained by adding the solvent and the additive while stirring so that the composition of the obtained liquid crystal aligning agent became the composition shown in table 2, and stirring at room temperature for 2 hours.

TABLE 2

	Polymer 1	Additive 2	Solvent ratio 3
				Example 2	MP1(100)	E1(3)	NMP(70)，BCS(20)
Comparative example 3	MP1(100)	-	NMP(70)，BCS(20)
				Comparative example 4	MP1(100)	E2(3)	NMP(70)，BCS(20)

Hereinafter, a method for manufacturing a liquid crystal cell for evaluating the relaxation property, the flicker property, and the liquid crystal alignment property of the accumulated charge will be described.

A liquid crystal cell having a structure of an FFS mode liquid crystal display element was fabricated. First, a substrate with electrodes is prepared. The substrate is a glass substrate with the longitudinal direction of 30mm, the transverse direction of 35mm and the thickness of 0.7 mm. An IZO electrode constituting a counter electrode is formed on the entire surface of the substrate as the 1 st layer. A SiN (silicon nitride) film formed by a CVD method is formed as the 2 nd layer on the 1 st layer counter electrode. The SiN film of layer 2 has a thickness of 500nm and functions as an interlayer insulating film. On the SiN film of the 2 nd layer, a comb-tooth-shaped pixel electrode formed by patterning the IZO film is arranged as the 3 rd layer, and 2 pixels, i.e., 1 st pixel and 2 nd pixel, are formed. The size of each pixel is about 10mm in the longitudinal direction and about 5mm in the transverse direction. At this time, the counter electrode of layer 1 and the pixel electrode of layer 3 are electrically insulated by the SiN film of layer 2.

The pixel electrode of the 3 rd layer has a comb-like shape formed by arranging a plurality of v-shaped electrode elements whose central portions are curved. The width of each electrode element in the short side direction was 3. Mu.m, and the interval between the electrode elements was 6. Mu.m. The pixel electrode forming each pixel is formed by arranging a plurality of v-shaped electrode elements bent at the central portion, and therefore, the shape of each pixel is not rectangular, but has a shape similar to a bold v-shaped electrode element bent at the central portion. Each pixel is divided into an upper and a lower regions with a curved portion at the center thereof as a boundary, and has a 1 st region on the upper side and a 2 nd region on the lower side of the curved portion.

If the 1 st region and the 2 nd region of each pixel are compared, the formation directions of the electrode elements constituting their pixel electrodes are different. That is, in the case of the rubbing direction of the liquid crystal alignment film to be described later, the electrode element of the pixel electrode is formed at an angle of +10° (clockwise) in the 1 st region of the pixel, and the electrode element of the pixel electrode is formed at an angle of-10 ° (clockwise) in the 2 nd region of the pixel. That is, the 1 st region and the 2 nd region of each pixel are configured as follows: the directions of the rotation operation (in-plane switching) of the liquid crystal in the substrate surface caused by the voltage applied between the pixel electrode and the counter electrode are made opposite to each other.

Next, the liquid crystal aligning agents obtained in examples and comparative examples were filtered by a filter having a pore diameter of 1.0 μm, and then spin-coated on the prepared charged substrates. After drying on a hot plate at 80℃for 2 minutes, the polyimide film was baked for 20 minutes using a hot air circulation oven at 230℃to obtain a polyimide film having a film thickness of 60 nm. The polyimide film was rubbed with a rayon cloth (roller diameter: 120mm, roller rotation speed: 500rpm, moving speed: 30mm/sec, press-in length: 0.3mm, rubbing direction: a direction inclined by 10 ° with respect to the IZO comb teeth electrode of layer 3), then subjected to ultrasonic irradiation in pure water for 1 minute, and washed, and water droplets were removed by air blowing. Thereafter, the substrate with the liquid crystal alignment film was obtained by drying at 80℃for 15 minutes. A polyimide film was formed on a glass substrate having a columnar spacer of 4 μm height, on the back surface of which an ITO electrode was formed, as a counter substrate, in the same manner as described above, and a substrate with a liquid crystal alignment film subjected to alignment treatment was obtained by the same procedure as described above. The 2 substrates with liquid crystal alignment films were set as 1 group, a sealant was printed in a shape such that a liquid crystal injection port remained on the substrates, and the other substrates were bonded such that the liquid crystal alignment film faces were opposed to each other and the rubbing directions were antiparallel. Thereafter, the sealant was cured to prepare a void cell having a cell gap of 4 μm. The empty cell was injected with liquid crystal MLC-3019 (manufactured by MELC co., ltd.) by a decompression injection method, and the injection port was sealed to obtain an FFS mode liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 120℃for 1 hour, and left at 23℃for one-touch evaluation of liquid crystal alignment.

< relaxation Property of accumulated Charge >)

The liquid crystal cell was placed between 2 polarizing plates arranged so that the polarizing axes were orthogonal, and the LED backlight was irradiated from below the 2 polarizing plates in advance in a state where the pixel electrode and the counter electrode were short-circuited and brought to the same potential, and the angle of the liquid crystal cell was adjusted so that the brightness of the transmitted light of the LED backlight measured on the 2 polarizing plates was minimized.

Next, V-T characteristics (voltage-transmittance characteristics) were measured at a temperature of 23 ℃ while applying a rectangular wave having a frequency of 30Hz to the liquid crystal cell, and an ac voltage having a relative transmittance of 23% was calculated. Since this ac voltage corresponds to a region where the change in luminance with respect to voltage is large, it is convenient to evaluate the accumulated charge by luminance.

Then, at a temperature of 23 ℃, the drive was performed for 30 minutes with an ac voltage having a relative transmittance of 23% and a dc voltage of +1.0v superimposed after applying a rectangular wave having a frequency of 30Hz for 5 minutes. Thereafter, the dc voltage was turned off, and only an ac voltage having a relative transmittance of 23% was applied again, and a rectangular wave having a frequency of 30Hz was applied again for 15 minutes.

Since the charge accumulation in the liquid crystal cell is faster when the dc voltage is superimposed as the accumulated charge is relaxed more rapidly, the relaxation characteristic of the accumulated charge is evaluated by the time required to decrease the relative transmittance by 2% or more from immediately after the dc voltage is superimposed. That is, the case where the relative transmittance was reduced by 2% or more within 30 minutes was defined as "good" for evaluation, and the case where the relative transmittance was not reduced by 2% or more after 30 minutes was defined as "poor" for evaluation.

< evaluation of liquid Crystal orientation >)

With this liquid crystal cell, an alternating voltage of 9VPP was applied at a frequency of 30Hz for 190 hours in a constant temperature environment at 60 ℃. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were brought into a short-circuited state, and left at room temperature for one day in this state.

After the liquid crystal cell was set between 2 polarizing plates arranged so that the polarizing axes were orthogonal, the backlight was previously lit in a state where no voltage was applied, and the arrangement angle of the liquid crystal cell was adjusted so that the brightness of the transmitted light became minimum. Then, the rotation angle at which the liquid crystal cell is rotated from the angle at which the 2 nd region of the 1 st pixel becomes the darkest to the angle at which the 1 st region becomes the darkest is calculated as the angle Δ. Similarly, the 2 nd pixel compares the 2 nd region with the 1 st region, and calculates the same angle Δ. Then, an average value of the angle Δ values of the 1 st pixel and the 2 nd pixel is calculated as the angle Δ of the liquid crystal cell. The liquid crystal cell was evaluated as "good" when the angle Δ was smaller than 0.2 degrees, and as "poor" when the angle Δ was equal to or larger than 0.2 degrees.

< evaluation of Voltage Holding Rate (VHR) >)

The obtained liquid crystal cell was applied with a voltage of 1V at 60 ℃ for 60 μs, the voltage after 50ms was measured, and the degree to which the voltage could be held was calculated as the voltage holding ratio. The voltage holding ratio was measured using a voltage holding ratio measuring device VHR-1 manufactured by TOYO Corporation.

< evaluation of optical Properties (transparency) >)

A quartz substrate having a longitudinal direction of 40mm, a transverse direction of 40mm and a thickness of 1.0mm was prepared. Then, the liquid crystal aligning agent was filtered through a 1.0 μm filter, and then spin-coated on the quartz substrate. Then, the resultant was dried on a hot plate at 80℃for 2 minutes, and then baked at 230℃for 20 minutes, whereby a polyimide film having a film thickness of 100nm was obtained on each substrate.

The transparency was evaluated by measuring the transmittance of the substrate obtained by the above method. Specifically, the transmittance was measured using UV-3600 (manufactured by Shimadzu corporation) at a temperature of 25℃and a scanning wavelength of 300 to 800 nm. At this time, reference (reference example) was made to a quartz substrate without any coating material. For the evaluation, the average transmittance at a wavelength of 400 to 800nm was calculated, and the higher the transmittance was, the more excellent the transparency was evaluated.

< evaluation result >

The results of the evaluation of the afterimage removal time, the evaluation of the stability of the alignment of the liquid crystal, and the evaluation of the transparency of the liquid crystal display elements using the liquid crystal aligning agents of examples 1 to 4 and comparative examples 1 to 3 are shown in table 3.

TABLE 3

As is clear from table 3, the liquid crystal display element using the liquid crystal aligning agent of example 1 was excellent in voltage holding ratio, rapid in relaxation of accumulated charges, good in liquid crystal alignment property and transparency.

Industrial applicability

The liquid crystal aligning agent of the present application can be widely used in liquid crystal display elements of longitudinal electric field systems such as TN system and VA system, and in particular, in transverse electric field systems such as IPS system and FFS system.

The entire contents of the specification, claims and abstract of japanese patent application No. 2018-51092, filed on 3/19 in 2018, are hereby incorporated by reference as if the disclosure of the present specification was incorporated herein.

Claims

1. A liquid crystal aligning agent comprising the following component (A), component (B) and an organic solvent,

(A) The components are as follows: at least one polymer selected from the group consisting of a polyimide precursor, an imidized polymer of the polyimide precursor, and a side chain type acrylic polymer exhibiting liquid crystallinity in a temperature range of 100 to 300 DEG C

In the formula (1), Q ¹ Is of the formula (Q1-1), Q ² Is of the formula (Q1-1), Q1 and Q2 are each independently 0 or 1, R ² R is R ³ Each independently is a group having an epoxy moiety or a hydrogen atom, R ² R is R ³ At least one of which is a group having an epoxy moiety,

in the formula (1), R ¹ Is a hydrogen atom or a monovalent organic group.

2. The liquid crystal aligning agent according to claim 1, wherein the polyimide precursor as the component (A) has a structural unit represented by the following formula (A1),

in the formula (A1), X ₁ An organic group of valence 4, Y ₁ An organic group of valence 2, R ₁ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, A ₁ A is a ₂ Each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may be substituted, an alkenyl group having 2 to 10 carbon atoms which may be substituted, or an alkynyl group having 2 to 10 carbon atoms which may be substituted.

3. The liquid crystal aligning agent according to claim 2, wherein in the formula (A1), Y ₁ Is at least one selected from the structures (5) and (6) represented by the following formulas,

in the formula (5), R ₁₂ Is a single bond or a 2-valent organic group having 1 to 30 carbon atoms, R ₁₃ A is a hydrogen atom, a halogen atom or a 1-valent organic group having 1 to 30 carbon atoms, a is an integer of 1 to 4, and when a is 2 or more, 2 or more R's are represented by ₁₂ More than 2R ₁₃ Optionally identical or different, in formula (6), R ₁₄ Is a single bond, -O-, -S-, -NR ₁₅ -, an amide bond, an ester bond, a urea bond, or a 2-valent organic group having 1 to 40 carbon atoms, R ₁₅ Is a hydrogen atom or a methyl group.

4. The liquid crystal aligning agent according to claim 1, wherein the side chain type acrylic polymer which is the component (A) and exhibits liquid crystallinity in a temperature range of 100 to 300 ℃ has a side chain structure composed of at least one of the following formulas (i) to (v),

ar in the formulae (i) to (v) ₁ To remove 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring,

Ar ₂ ar and Ar ₃ Each independently is a substituent of 2 valencies obtained by removing 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring, one of q1 and q2 is 1, the other is 0, ar ₄ Ar and Ar ₅ Each independently represents a substituent having a valence of 2 obtained by removing 2 hydrogen atoms from a benzene ring, naphthalene ring, pyrrole ring, furan ring, thiophene ring or pyridine ring, Y ₁ Y and Y ₂ Each independently is-ch=ch-, -ch=n-, -n=ch-, or-c≡c-, S is S ₁ 、S ₂ S and S ₃ Each independently represents a single bond, a linear or branched alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a phenylene group, a biphenylene group, or a substituent having 2 to 10 valences formed by a combination of these groups, wherein the plurality of substituents having 2 valences are optionally each represented by a single bond, an ether bond, an ester bond, an amide bond, a urea bond, a urethane bond, or an ammonia bond A structure formed by connecting a base bond and a carbonyl bond, R ₁₁ Is a hydrogen atom, a hydroxyl group, a mercapto group, an amino group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 8 carbon atoms, or a dialkylamino group having 2 to 16 carbon atoms.

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the compound represented by the component (B) is at least one selected from the following formulas (B-1) to (B-4),

(B-1): in the formula (1), Q1 and Q2 are 0 and Q ¹ Is (Q1-1), R ² R is R ³ A compound having an epoxy group,

(B-2): in the formula (1), Q1 and Q2 are 0 and Q ¹ Is (Q1-1), R ² Is a hydrogen atom, R ³ A compound having an epoxy group,

(B-3): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is (Q1-1), Q ² Is (Q1-1), R ² R is R ³ A compound having an epoxy group,

(B-4): in the formula (1), Q1 and Q2 are 1 and Q ¹ Is (Q1-1), Q ² Is (Q1-1), R ² Is a hydrogen atom, R ³ A compound which is a group having an epoxy group.

6. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the compound of the component (B) is at least one selected from the following formulas Q1-1-1 to Q1-1-4 and Q1-1-6,

7. the liquid crystal aligning agent according to any one of claims 1 to 4, wherein the organic solvent is N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ -butyrolactone, 1, 3-dimethyl-imidazolidinone, methylethylketone, cyclohexanone, cyclopentanone, or 4-hydroxy-4-methyl-2-pentanone.

8. The liquid crystal aligning agent according to claim 7, wherein the organic solvent further comprises a solvent for improving film coating property and surface smoothness of the liquid crystal aligning film.

9. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the polymer containing the component (A) is contained in an amount of 1 to 10% by mass in the liquid crystal aligning agent.

10. The liquid crystal aligning agent according to claim 9, wherein the component (B) is contained in an amount of 0.1 to 20% by mass based on the component (A).

11. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 10.

12. A liquid crystal display element comprising the liquid crystal alignment film according to claim 11.