KR20200132907A - Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element - Google Patents

Abstract

(R⁵ 는 단결합 등, R⁶ 은 -(CH₂)_n- 의 구조, n 은 2 ∼ 20, R⁷ 은 단결합 등)
(B) 성분 : 하기 식 (1) 로 나타내는 화합물
[화학식 2]

(Q¹, Q² 는 하기 (Q1-1), (Q1-2) 등)
[화학식 3]

(q1, q2 는 0 또는 1, R¹ 은 수소 원자 등, L¹, L² 는 수소 원자 등, S¹, S² 는 하기 식 (S) 로 나타내는 기)
[화학식 4]

(R² 는 수소 원자 등, L 은 탄소수 2 ∼ 20 의 알킬렌 등, R³, R⁴ 는, 탄소수 1 ∼ 4 의 알킬기 등, q 는 1 ∼ 3, * 는 식 (1) 에 대한 결합 위치)A liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element capable of obtaining a liquid crystal aligning film having excellent voltage retention, quick relaxation of accumulated charge, and excellent liquid crystal aligning property and transparency are provided.
The liquid crystal aligning agent characterized by containing the following (A) component, (B) component, and an organic solvent.
Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a structure of the following formula (2) and an imidized polymer of the polyimide precursor
[Formula 1]

(R ⁵ is a single bond, R ⁶ is a structure of -(CH ₂ ) _n -, n is 2 to 20, R ⁷ is a single bond, etc.)
(B) component: compound represented by following formula (1)
[Formula 2]

(Q ¹ and Q ² are the following (Q1-1), (Q1-2), etc.)
[Formula 3]

(q1 and q2 are 0 or 1, R ¹ is a hydrogen atom, etc., L ¹ and L ² are a hydrogen atom, etc., S ¹ and S ² are groups represented by the following formula (S))
[Formula 4]

(R ² is a hydrogen atom, L is an alkylene having 2 to 20 carbon atoms, etc., R ³ and R ⁴ are an alkyl group having 1 to 4 carbon atoms, etc., q is 1 to 3, * is a bonding position to formula (1) )

Description

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

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

Liquid crystal display elements are widely used as display units for personal computers, mobile phones, smart phones, and televisions. The liquid crystal display device includes, for example, a liquid crystal layer sandwiched between an element substrate and a 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 the alignment of liquid crystal molecules in the liquid crystal layer, and a pixel electrode. A thin film transistor (TFT) or the like for switching the supplied electric signal is provided. As a driving method of liquid crystal molecules, a vertical electric field method such as a TN method and a VA method, and a transverse electric field method such as an IPS method and an FFS method are known. In the transverse electric field method in which an electrode is formed only on one side of the substrate and an electric field is applied in a direction parallel to the substrate, compared to the vertical electric field method in which a voltage is applied to the electrodes formed on the upper and lower substrates to drive the liquid crystal, the wide viewing angle characteristic is achieved. It has and is known as a liquid crystal display element capable of displaying high quality.

Although the transverse electric field type liquid crystal cell has excellent viewing angle characteristics, since there are few electrode portions formed in the substrate, if the voltage retention is low, a sufficient voltage is not applied to the liquid crystal, and the display contrast decreases. In addition, if the stability of the liquid crystal alignment is small, the liquid crystal does not return to the initial state when the liquid crystal is driven for a long time, resulting in a decrease in contrast or an afterimage, so the stability of the liquid crystal alignment is important. In addition, static electricity is liable to accumulate in the liquid crystal cell, and charges are accumulated in the liquid crystal cell even by the application of a positive and negative asymmetric voltage generated by driving, and these accumulated charges affect the display as a disturbance in liquid crystal alignment or an afterimage. Given, the display quality of a liquid crystal element is remarkably reduced.

When used in such a transverse electric field type liquid crystal display device, as a liquid crystal aligning agent having excellent voltage retention and reduced charge accumulation, Patent Document 1 discloses a liquid crystal alignment containing a specific diamine and an aliphatic tetracarboxylic acid derivative. I have been disclosed. In addition, as a method of shortening the time until the afterimage disappears, an alignment film having a low volume resistivity as in Patent Document 2 or an alignment film in which the volume resistivity does not change well even by the backlight of a liquid crystal display device as in Patent Document 3 How to use is proposed. However, as the performance of the liquid crystal display device is improved, the characteristics required for the liquid crystal alignment film are also becoming strict, and it is difficult to sufficiently satisfy all the required characteristics with these conventional techniques.

International Publication (WO) 2004/021076 pamphlet International Publication (WO) 2004/053583 pamphlet International Publication (WO) 2013/008822 pamphlet

The present invention is excellent in voltage retention, quick relaxation of accumulated charge, and a liquid crystal alignment film having good liquid crystal alignment and transparency can be obtained. In particular, characteristics in a display element of a transverse electric field system such as an IPS system and an FFS system It makes it a subject to provide an excellent liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element.

The inventors of the present invention have completed the present invention as a result of intensive examination in order to solve the above problems.

That is, this invention makes a liquid crystal aligning agent characterized by containing the following (A) component, (B) component, and an organic solvent as a summary.

Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a structure of the following formula (2) and an imidized polymer of the polyimide precursor

[Formula 1]

However, in formula (2), R ⁵ is a single bond or a divalent organic group, R ⁶ is a structure represented by -(CH ₂ ) _n- , n is an integer of 2 to 20, and any -CH _2- May be substituted with a bond selected from ether, ester and amide under conditions that are not adjacent to each other, R ⁷ is a single bond or a divalent organic group, and any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.

(B) component: compound represented by following formula (1)

[Formula 2]

However, in formula (1), Q ¹ and Q ² are each independently one species selected from the following (Q1-1), (Q1-2) and single bonds, but in formula (1), Q ¹ and Q At least one of ² is one species selected from (Q1-1) and (Q1-2). R ¹ is a hydrogen atom or a monovalent organic group.

[Formula 3]

q1 and q2 are each independently 0 or 1,

L ¹ and L ² are hydrogen atoms. However, when Q ¹ is (Q1-1), L ¹ and L ² may become one to form a single bond.

S ¹ and S ² are each independently a group represented by the following formula (S).

[Formula 4]

In the formula, R ² represents a hydrogen atom or an alkyl group, L represents an alkylene having 2 to 20 carbon atoms, and R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms Or, it is a C2-C4 alkynyl group, and q represents a natural number of 1-3. * Represents a bond to formula (1).

By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film capable of obtaining a liquid crystal alignment film having excellent voltage retention, fast relaxation of accumulated charge, and good liquid crystal alignment and transparency, and, in particular, a horizontal layer such as an IPS method and an FFS method. A liquid crystal display device having excellent display characteristics in an electric field type display device is provided. Although it is not clear why the above problems can be solved by the present invention, it is generally considered as follows. In the liquid crystal aligning agent of the present invention, the structure of the compound represented by the formula (1) which is the component (B) contained together with the component (A) has a conjugated structure, so that, for example, in a liquid crystal aligning film, It can promote the movement of energy and promote the relaxation of accumulated electric charges.

<(A) component>

The component (A) contained in the liquid crystal aligning agent of the present invention is at least one polymer selected from the group consisting of a polyimide precursor having a structure represented by the following formula (2), and an imidized polymer of the polyimide precursor ( Hereinafter, it is also referred to as a specific polymer (A)).

[Formula 5]

However, the definition of each symbol in Formula (2) is as above, respectively.

R ⁵ is a single bond or a divalent organic group, R ⁶ is a structure represented by -(CH ₂ ) _n -, n is an integer from 2 to 20, and any -CH ₂ -is not adjacent to each other. It may be substituted with a bond selected from ether, ester and amide, R ⁷ is a single bond or a divalent organic group, and any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.

In addition, as the divalent organic group constituting R ⁵ , a phenyl group (hereinafter referred to as -Ph-), -Ph-(CH ₂ ) _m- (m is an integer of 1 to 10), -Ph-O-,- Ph-OC(=O)-, -Ph-C(=O)-O-, -Ph-C=CO-, etc. are mentioned. R ⁵ is preferably a single bond or a phenyl group.

In addition, as the divalent organic group constituting R ⁷ , -(Ph) _k- (k is an integer of 1 to 3), -Ph-(CH ₂ ) _m -Ph- (m is an integer of 1 to 10), -Ph-(CH ₂ ) _l -Ph-(CH ₂ ) _m -Ph- (l and m are each independently integers of 1 to 10), -Ph-O-Ph-, -Ph-OC(=O) -Ph-, -Ph-C(=O)-O-Ph-, -Ph-C=CO-Ph-, etc. are mentioned. Among these, R ⁷ is preferably a phenyl group or -Ph-(CH ₂ ) _m -Ph- (m is an integer of 1 to 10).

It is preferable that n in Formula (2) is an integer of 1-10. Further, the monovalent organic group of the hydrogen atom of the benzene ring is preferably a group selected from a fluorine atom and a methyl group.

Although the following are mentioned specifically as a structure represented by Formula (2), It is not limited to these. In addition, Me in the following formula represents a methyl group.

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

As the specific polymer (A) in the present invention, a polymer obtained using a diamine having a structure represented by the above formula (2) is preferable. As a specific example of a specific polymer (A), polyamic acid, a polyamic acid ester, polyimide, etc. are mentioned. From a viewpoint as a liquid crystal aligning agent, it is preferable that a specific polymer (A) is at least 1 type selected from the polyimide precursor containing a structural unit represented by following formula (3), and the polyimide which is an imidation product among them. .

[Formula 11]

However, in formula (3), X ³ is a tetravalent organic group derived from a tetracarboxylic acid derivative. Specifically, at least one member selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-45) is preferable.

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

In formula (X1-1), R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ are each independently 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, Or a phenyl group. From the viewpoint of liquid crystal orientation, R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

X ³ is, among these, from the viewpoint of liquid crystal alignment property, reliability, (X1-10), (X1-11) , or (X1-29) are preferable, (X1-10) or (X1-11) than the desirable.

In the formula (3), Y ₃ is a divalent organic group derived from a diamine containing the structure of formula (2), and from the viewpoint of orientation, in the diamine wherein R ⁷ is a single bond or a benzene ring in the formula (2) It is preferable that it is a derived divalent organic group. R ¹³ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom or a methyl group is particularly preferable from the viewpoint of easy imidization by heating.

In the specific polymer (A) in the present invention, the ratio of at least one structural unit selected from the structural unit represented by the above formula (3) and the structural unit imidized therein to all structural units in the specific polymer (A) On the other hand, it is preferable to contain from 20 to 100 mol%, and it is more preferable to contain from 30 to 70 mol% from the viewpoint of both liquid crystal orientation and reliability, and still more preferably from 50 to 70 mol%.

In addition to the structural unit represented by the above formula (3), the specific polymer (A) in the present invention may further have a structural unit represented by the following formula (4) and/or a structural unit imidized therein. .

[Formula 18]

However, in formula (4), R ¹⁴ is the same as the definition of R ¹³ in the formula (3). X ₄ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. For example, the structures of the formulas (X1-1) to (X-45) can be cited.

In the formula (4), Y ₄ is a divalent organic group derived from a diamine, and the structure is not particularly limited. As a specific example of Y ₄ , structures of the following formulas (Y-1) to (Y-140) are mentioned.

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

[Formula 24]

[Formula 25]

[Formula 26]

[Formula 27]

[Formula 28]

[Chemical Formula 29]

[Formula 30]

[Formula 31]

[Formula 32]

[Formula 33]

[Formula 34]

When the specific polymer (A) contains a polyimide obtained by imidating a polyimide precursor, the ratio of the imidized structural unit (also referred to as an imidation ratio) can be arbitrarily adjusted according to the properties of the liquid crystal aligning agent. From the viewpoint of voltage retention, it is preferable that the imidation ratio in the specific polymer (A) is high, but when it is excessively high, the solubility deterioration is concerned, so the imidation ratio is preferably 40 to 95%, More preferably, it is 55 to 90%.

The polyimide precursor used in the present invention is obtained from the reaction of a diamine component and a tetracarboxylic acid derivative, and includes polyamic acid and polyamic acid ester.

<Polyimide precursor (polyamic acid)>

The polyamic acid, which is a polyimide precursor used in the present invention, is produced by the following method. Specifically, reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent at -20 to 150°C, preferably 0 to 50°C, for 30 minutes to 24 hours, preferably 1 to 12 hours It can be manufactured by letting you do it.

The reaction of the diamine component and the tetracarboxylic acid component is usually performed in an organic solvent. The organic solvent used at that time is not particularly limited as long as the produced polyimide precursor is dissolved. Below, although the specific example of the organic solvent used for reaction is given, it is not limited to these examples. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide or And 1,3-dimethyl-imidazolidinone.

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

[Formula 35]

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

These organic solvents may be used alone or in combination. Moreover, even if it is a solvent which does not melt|dissolve a polyimide precursor, you may mix and use with the said solvent within the range in which the produced|generated polyimide precursor does not precipitate. In addition, since moisture in the organic solvent inhibits the polymerization reaction and furthermore causes hydrolysis of the produced polyimide precursor, it is preferable to use a dehydration-dried 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, from the viewpoint that precipitation of the polymer does not occur easily and high molecular weight is easily obtained.

The polyamic acid obtained as described above can be recovered by depositing a polymer by pouring it into a poor solvent while stirring the reaction solution well. Further, by performing precipitation several times, washing with a poor solvent, drying at room temperature or by heating, a purified polyamic acid powder can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. are mentioned.

<Polyimide precursor (polyamic acid ester)>

The polyamic acid ester which is a polyimide precursor used in the present invention can be produced by the production method of (1), (2) or (3) shown below.

(1) When manufacturing from polyamic acid

The polyamic acid ester can be produced by esterifying a polyamic acid. Specifically, prepared by reacting a polyamic acid and an esterifying agent in the presence of an organic solvent at -20 to 150°C, preferably 0 to 50°C, for 30 minutes to 24 hours, preferably 1 to 4 hours. can do.

As the esterifying agent, those that can be easily removed by purification are preferred. For example, N,N-dimethylformamide dimethylacetal, N,N-dimethylformamide diethylacetal, N,N-dimethylformamidedipropylacetal, N,N-dimethylformamide dineopentylbutylacetal, N ,N-dimethylformamidedi-t-butylacetal, 1-methyl-3-p-tolyltriagen, 1-ethyl-3-p-tolyltriagen, 1-propyl-3-p-tolyltriazine, 4 -(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium chloride, etc. are mentioned. The amount of the esterifying agent added is preferably 2 to 6 mole equivalents per 1 mole of the repeating unit of the polyamic acid.

As an organic solvent, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide , Dimethyl sulfoxide or 1,3-dimethyl-imidazolidinone. In addition, when the solvent solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the above formula [D-1] to formula [ The organic solvent represented by D-3] can be used.

These organic solvents may be used alone or in combination. Moreover, even if it is a solvent which does not melt|dissolve a polyimide precursor, you may mix and use with the said solvent within the range in which the produced|generated polyimide precursor does not precipitate. In addition, since moisture in the organic solvent inhibits the polymerization reaction and furthermore causes hydrolysis of the produced polyimide precursor, it is preferable to use a dehydration-dried organic solvent.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer, and these are one or two or more. You may mix and use. The concentration at the time of production is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass, from the viewpoint that precipitation of the polymer does not occur easily and high molecular weight is easily obtained.

(2) When produced by reaction of tetracarboxylic acid diester dichloride and diamine

Polyamic acid ester can be manufactured from tetracarboxylic acid diester dichloride and diamine. Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent, in the presence of a base and an organic solvent, at -20 to 150°C, preferably 0 to 50°C, for 30 minutes to 24 hours, preferably 1 to It can be manufactured by making it react for 4 hours.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine, or the like can be used, but pyridine is preferred because the reaction proceeds gently. The amount of the base added is preferably 2 to 4 times mole relative to the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and easy to obtain a high molecular weight body.

As the organic solvent, N-methyl-2-pyrrolidone or γ-butyrolactone is preferable from the solubility of the monomer and polymer, and these may be used singly or in combination of two or more.

The polymer concentration at the time of production is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer does not occur easily and high molecular weight is easily obtained. In addition, in order to prevent hydrolysis of 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 mixing of outside air in a nitrogen atmosphere. Do.

(3) When producing from tetracarboxylic acid diester and diamine

The polyamic acid ester can be produced by polycondensing a tetracarboxylic acid diester and a diamine. Specifically, in the presence of a condensing agent, a base, and an organic solvent, tetracarboxylic acid diester and diamine are mixed at 0 to 150°C, preferably 0 to 100°C, for 30 minutes to 24 hours, preferably 3 It can be manufactured by making it react for -15 hours.

Examples of the condensing agent include triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1 ,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazole- 1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzooxazolyl) phosphonic acid diphenyl, etc. I can. The amount of the condensing agent added is preferably 2 to 3 times mole relative to the tetracarboxylic acid diester.

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

In addition, in the above reaction, by adding Lewis acid as an additive, the reaction proceeds efficiently. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The amount of Lewis acid added is preferably 0 to 1.0 times mole relative to the diamine component.

Among the above three methods for producing polyamic acid esters, since a high molecular weight polyamic acid ester can be obtained, the production method of the above (1) or (2) is particularly preferred.

The polymer can be precipitated by injecting the solution of the polyamic acid ester obtained as described above into a poor solvent while stirring well. Precipitation is carried out several times, washed with a poor solvent, and then dried at room temperature or by heating to obtain a purified polyamic acid ester powder. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. are mentioned.

<Polyimide>

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

When producing a polyimide from a polyamic acid, chemical imidization in which a catalyst is added and reacted to a solution of the polyamic acid obtained by reaction of a diamine component and tetracarboxylic dianhydride is simple. This chemical imidation is preferable because the imidation reaction proceeds at a relatively low temperature, and the molecular weight of the polymer is less likely to decrease in the process of imidation.

Chemical imidation can be performed by stirring the polyamic acid to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, an organic solvent 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 basicity suitable for advancing the reaction. Further, examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Among them, acetic anhydride is preferably used because purification after completion of the reaction becomes easy.

The temperature at the time of carrying out the imidation reaction is -20 to 140°C, preferably 0 to 100°C, and the reaction time can be performed for 0.5 to 100 hours, preferably 1 to 80 hours. The amount of the basic catalyst is 0.5 to 30 mole times, preferably 2 to 20 mole times of amic acid, and the amount of the acid anhydride is 1 to 50 mole times, preferably 3 to 30 mole times of the amic acid. The imidation ratio of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

Since the added catalyst or the like remains in the solution after the imidation reaction of the polyamic acid ester or the polyamic acid, the obtained imidized polymer is recovered by the means described below, and re-dissolved in an organic solvent, according to the present invention. It is preferable to use it as (A) component of a liquid crystal aligning agent.

A polymer can be precipitated by injecting the polyimide solution obtained as described above into a poor solvent while stirring well. Precipitation is performed several times, washed with a poor solvent, and then dried at room temperature or heated to obtain a purified polyimide powder.

Although the said poor solvent is not specifically limited, Methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, etc. are mentioned.

<(B) component>

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

[Formula 36]

However, the definition of each symbol in Formula (1) is as above, respectively.

Further, the monovalent organic group in the formulas (Q1-1) and (Q1-2) is preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group.

L ¹ and L ² are hydrogen atoms. However, when Q ¹ is (Q1-1), for example, like a compound represented by the later formula B-5-1, L ¹ and L ² may become one to form a single bond.

S ¹ and S ² are each independently a group represented by the following formula (S).

[Formula 37]

In the formula, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, L represents an alkylene having 2 to 20 carbon atoms, and R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms and 2 It is an alkenyl group of -4 or a C2-C4 alkynyl group, and q represents a natural number of 1-3. * Represents a bond to formula (1).

The monovalent organic group for R ¹ is more preferably a methyl group, a phenyl group, or a thermally decomposable leaving group.

The thermally decomposable leaving group refers to a substituent which is removed by heating and replaced with a hydrogen atom. Such a thermally decomposable leaving group is a protecting group of an amino group, and its structure is not particularly limited as long as it is a functional group substituted with a hydrogen atom by heat. In terms of storage stability of the liquid crystal aligning agent, this protecting group D is preferably not desorbed at room temperature, preferably is a protecting group desorbed by heat at 80°C or higher, and more preferably is a protecting group desorbed by heat at 100°C or higher. . D is particularly preferably a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group from the viewpoint of the temperature at which it desorbs.

Preferred examples of the compound represented by the component (B) include, for example, the compounds of the following (B-1) to (B-9).

(B-1): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-1), L ¹ and L ² are a hydrogen atom,

(B-2): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-1), L ¹ and L ² become one to form a single bond,

(B-3): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is (Q1-1), and L ¹ and L ² are hydrogen atoms. compound,

(B-4): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is a single bond, L ¹ and L ² are a hydrogen atom,

(B-5): In the above formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is (Q1-1), and L ¹ and L ² become one Compounds that are single bonds,

(B-6): In the formula (1), q1 and q2 are 1, Q ¹ is a single bond, Q ² is (Q1-1), L ¹ and L ² are a hydrogen atom,

(B-7): In the above formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is a single bond, and L ¹ and L ² become one to be a single bond. compound,

(B-8): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-2), and L ¹ and L ² are hydrogen atoms.

(B-9): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-2), and L ¹ and L ² are a hydrogen atom.

As a preferred specific example of the compound represented by the component (B), at least one selected from the group consisting of compounds represented by the following formulas B-1-1 to B-9-1 can be mentioned.

[Formula 38]

The compound of component (B) in the present invention is obtained by reacting a diamine represented by the following formula (0) with trialkoxysilylpropyl isocyanate by a known method.

[Formula 39]

Q ¹ , Q ² , L ¹ , L ² , q1 and q2 in Formula (0) are the same as the definition in Formula (1). As the diamine represented by these formula (0), a known one may be used.

In the reaction of the diamine and isocyanate, the amount of the isocyanate compound used is preferably 0.98 to 1.2 equivalent times, more preferably 1.0 to 1.05 equivalent times, with respect to one amino group.

The reaction solvent is not particularly limited as long as it is inert to the reaction. Hydrocarbons, such as hexane, cyclohexane, benzene, and toluene, for example; Halogenated hydrocarbons such as carbon tetrachloride, chloroform, and 1,2-dichloroethane; Ethers such as diethyl ether, diisopropyl ether, 1,4-dioxane, and tetrahydrofuran; Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Nitriles such as acetonitrile and propionitrile; Carboxylate esters, such as ethyl acetate and ethyl propionate; Nitrogen-containing aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone; Sulfur-containing aprotic polar solvents such as dimethyl sulfoxide and sulfolane; Pyridines, such as pyridine and picoline, etc. are mentioned. These solvents may be used alone, or two or more of them may be mixed and used. Toluene, acetonitrile, ethyl acetate, and tetrahydrofuran are preferred, and acetonitrile and tetrahydrofuran are more preferred.

The amount of the solvent used (reaction concentration) is not particularly limited, and the reaction may be carried out without using a solvent, and when a solvent is used, 0.1 to 100 mass times of a solvent may be used with respect to the isocyanate compound. It is preferably 0.5 to 30 times by mass, more preferably 1 to 10 times by mass.

The reaction temperature is not particularly limited, but is, for example, -90°C to 150°C, preferably -30°C to 100°C, and more preferably 0°C to 80°C. The reaction time is usually 1 minute to 200 hours, preferably 30 minutes to 100 hours.

If the component (B) is too large, the liquid crystal orientation will be affected, and if there is too little, the effect of the present invention is not obtained. Therefore, the addition amount of the component (B) is preferably 0.1 to 20 mass%, and more preferably 1 to 10 mass% with respect to the component (A) (100 mass%).

<Liquid crystal aligning agent>

The liquid crystal aligning agent used for this invention has the form of a solution in which the compound represented by the formula (1) which is the specific polymer (A) which is the component (A), and the formula (1) which is the component (B) is dissolved in an organic solvent. The molecular weight of the specific structural polymer (A) is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000 in terms of weight average molecular weight. Further, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

The concentration of the specific polymer (A) of the liquid crystal aligning agent of the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, but is preferably 1% by weight or more from the viewpoint of forming a uniform and defect-free coating film. In terms of storage stability of the solution, 10% by weight or less is preferable, and among them, it is preferably 1 to 5% by weight.

It is preferable that the organic solvent contained in the liquid crystal aligning agent used for this invention is a good (good) solvent in which a specific polymer (A) is dissolved uniformly.

As an organic solvent, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ -Butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, or 4-hydroxy-4-methyl-2-pentanone.

It is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone as the organic solvent, among others.

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

It is preferable that the good solvent in the liquid crystal aligning agent of this invention is 20-99 mass% of the whole solvent contained in a liquid crystal aligning agent. Especially, 20 to 90 mass% is preferable. A more preferable thing is 30 to 80 mass %.

The liquid crystal aligning agent of this invention can use a solvent (it is also called a poor solvent) which improves the coating film property and surface smoothness of a liquid crystal aligning film when a liquid crystal aligning agent is applied. Below, although a specific example of a poor solvent is given, it is not limited to these examples.

For example, 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-pentyl 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-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methyl Cyclohexanol, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, 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, propylene glycol monobutyl ether, 1-(butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether , Dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol di Acetate, diethylene glycol monoethyl ether acetate T, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, lactic acid Ethyl, 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, 3-methoxypropionic acid propyl, 3-methoxypropionate butyl, lactate methyl ester, lactate ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactate isoamyl ester, or The solvent etc. which are represented by said formula [D-1]-formula [D-3] are mentioned.

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

It is preferable that these poor solvents are 1 to 80 mass% of the whole solvent contained in a liquid crystal aligning agent. Especially, 10 to 80 mass% is preferable. It is more preferable that it is 20 to 70 mass %.

In the liquid crystal aligning agent of the present invention, in addition to the above, polymers other than the polymer described in the present invention, dielectrics or conductive materials for the purpose of changing electrical properties such as dielectric constant or conductivity of the liquid crystal alignment film, and the purpose of improving the adhesion between the liquid crystal aligning film and the substrate Silane coupling agent, a crosslinkable compound intended to increase the hardness and density of the film when used as a liquid crystal aligning film, and furthermore, an imidization accelerator for the purpose of efficiently progressing imidation by heating a polyimide precursor when firing a coating film You may add etc.

<Liquid crystal alignment film>

The liquid crystal aligning film of this invention is a film obtained by apply|coating the said liquid crystal aligning agent to a board|substrate, and drying and baking. 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 a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, and a polycarbonate substrate can be used, and an ITO electrode for driving a liquid crystal It is preferable to use a substrate on which the etc. are formed from the viewpoint of simplification of the process. In addition, in a reflective liquid crystal display device, an opaque material such as a silicon wafer can be used as long as it is only on the substrate on one side, and in this case, a material that reflects light such as aluminum can also be used.

As a coating method of the liquid crystal aligning agent of this invention, a spin coating method, a printing method, an inkjet method, etc. are mentioned. The drying and baking process after applying the liquid crystal aligning agent of this invention can select arbitrary temperature and time. Usually, in order to sufficiently remove the organic solvent contained, it is dried for 1 to 10 minutes at 50 to 120°C, and then fired at 150 to 300°C for 5 to 120 minutes. Although the thickness of the coating film after firing is not particularly limited, if it is too thin, the reliability of the liquid crystal display element may be lowered, so it is 5 to 300 nm, preferably 10 to 200 nm.

A rubbing method, a photoalignment treatment method, etc. are mentioned as a method of aligning the obtained liquid crystal aligning film.

The rubbing treatment can be performed using an existing rubbing device. Examples of the material of the rubbing cloth at this time include cotton, nylon, rayon, and the like. As the conditions of the rubbing treatment, generally, a rotation speed of 300 to 2000 rpm, a feed speed of 5 to 100 mm/s, and a press fit amount of 0.1 to 1.0 mm are used. After that, the residue generated by rubbing is removed by ultrasonic cleaning using pure water or alcohol.

As a specific example of the photoalignment treatment method, a method of irradiating the surface of the coating film with radiation deflected in a certain direction, and optionally further performing heat treatment at a temperature of 150 to 250°C to impart liquid crystal alignment ability. Can be lifted. As radiation, ultraviolet rays and visible rays having a wavelength of 100 to 800 nm can be used. Among these, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and those having a wavelength of 200 to 400 nm are particularly preferable. Further, in order to improve the liquid crystal orientation, the coating substrate may be irradiated with radiation while heating at 50 to 250°C. The radiation dose is preferably 1 to 10,000 mJ/cm 2, and particularly preferably 100 to 5,000 mJ/cm 2. The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a predetermined direction.

The higher the extinction ratio of the polarized ultraviolet rays is, the higher the anisotropy can be imparted, which is preferable. Specifically, the extinction ratio of ultraviolet rays polarized in a straight line is preferably 10:1 or more, and more preferably 20:1 or more.

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

The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition product generated by irradiation with light. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 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 two or more.

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

In the present invention, the contact treatment of the film irradiated with polarized radiation and the solution containing the organic solvent is performed by a treatment in which the film and the liquid are preferably sufficiently contacted, such as immersion treatment and spray (spray) treatment. Among them, a method of immersing the film in a solution containing an organic solvent is preferably 10 seconds to 1 hour, more preferably 1 to 30 minutes. The contact treatment may be at room temperature or may be heated, but is preferably performed at 10 to 80°C, more preferably at 20 to 50°C. In addition, it is possible to implement a means of increasing contact such as ultrasonic waves, if necessary.

After the contact treatment, for the purpose of removing the organic solvent in the solution used, either rinsing (rinsing) or drying with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or both You may do it.

Further, the film subjected to the contact treatment with a solvent may be heated at 150°C or higher for the purpose of drying the solvent and reorienting the molecular chains in the film.

The heating temperature is preferably 150 to 300°C. The higher the temperature, the more promoted the rearrangement of the molecular chain, but too high a temperature may involve decomposition of the molecular chain. Therefore, as a heating temperature, 180-250 degreeC is more preferable, and 200-230 degreeC is especially preferable.

If the heating time is too short, the effect of reorienting the molecular chain may not be obtained, and if it is too long, the molecular chain may be decomposed. Therefore, 10 seconds to 30 minutes are preferable, and 1 minute to 10 minutes are more preferable. .

<Liquid crystal display element>

The liquid crystal display device of the present invention is characterized by including a liquid crystal alignment film obtained by the method for producing the liquid crystal alignment film.

In the liquid crystal display device of the present invention, after obtaining a substrate with a liquid crystal aligning film from the liquid crystal aligning agent of the present invention by the method for producing a liquid crystal aligning film, a liquid crystal cell is produced by a known method, and the liquid crystal display element is used. I did it.

As an example of a method for producing a liquid crystal cell, a liquid crystal display device having a passive matrix structure will be described as an example. Further, it may be a liquid crystal display element having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is formed 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 is provided on the other substrate. These electrodes can be used as ITO electrodes, for example, and are patterned so as to display a desired image. Next, on each substrate, an insulating film is formed by covering the common electrode and the segment electrode. The insulating film can be, for example, a film made of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, on each substrate, the liquid crystal aligning film of this invention is formed. Next, one substrate is polymerized with the other substrate facing each other with the alignment film surfaces facing each other, and the periphery is adhered with a sealing material. In order to control the gap between the substrates, a spacer is usually mixed with the sealing material. In addition, it is preferable to disperse spacers for controlling the gap between the substrates in the inner portion of the surface where the sealing material is not formed. A part of the sealing material is provided with an opening capable of filling liquid crystal from the outside.

Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing material through the opening formed in the sealing material. After that, this opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method using a capillary phenomenon in the atmosphere may be used. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is affixed to the surface of the two substrates opposite to the liquid crystal layer. By passing through the above process, the liquid crystal display element of this invention is obtained.

In the present invention, as the sealing agent, for example, a resin cured by UV irradiation or heating having reactive groups such as epoxy group, acryloyl group, methacryloyl group, hydroxyl group, allyl group, and acetyl group is used. . In particular, a cured resin system having reactive groups of both an epoxy group and a (meth)acryloyl group is preferable.

An inorganic filler may be blended with the sealing agent of the present invention for the purpose of improving adhesion and moisture resistance. The inorganic filler that can be used is not particularly limited. Specifically, 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, Zirconium oxide, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, and the like. Among them, spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, or aluminum silicate desirable. Inorganic fillers may be used in combination of two or more.

Example

Hereinafter, the present invention will be specifically described with reference to examples and the like, but the present invention is not limited to these examples. In addition, the meaning of the symbol of a compound and a solvent is as follows. Here, Boc represents a tertiary butyloxycarbonyl group.

[Formula 40]

[Formula 41]

[Formula 42]

<Organic solvent>

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

GBL: γ-butyrolactone, THF: tetrahydrofuran

(Measurement of ¹ H-NMR)

Equipment: Varian NMR system 400NB (400 ㎒) (manufactured by Varian), and JMTC-500/54/SS (500 ㎒) (manufactured by JEOL)

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

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

<Synthesis of additive S1>

[Formula 43]

In tetrahydrofuran (300 g), 4,4'-diamino-N-methyldiphenylamine (10.0 g, 43.2 mmol) was poured, and under ice cooling, 3-triethoxysilylpropyl isocyanate (23.5 g) The solution diluted with tetrahydrofuran (50 g) was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was stirred at room temperature for 24 hours. The reaction solution was concentrated under reduced pressure to make the inner volume 128 g. After heating and dissolution at 60° C., acetonitrile (300 g) was added and stirred at room temperature to precipitate crystals. The precipitated crystal was filtered and the filtrate was dried to obtain compound [S1] (amount: 22.8 g, yield: 75%, gray crystal).

<Synthesis of additive S2>

[Formula 44]

In tetrahydrofuran (150 g), [DA-4] (10.0 g, 23.7 mmol) was poured, and 3-triethoxysilylpropyl isocyanate (12.3 g) was converted into tetrahydrofuran (50 g) under ice cooling. The diluted solution was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was stirred at room temperature for 24 hours. The reaction solution was concentrated under reduced pressure, the inner volume was adjusted to 50 g, and then acetonitrile (100 g) was added and stirred at room temperature to precipitate crystals. The precipitated crystals were filtered and the filtrate was dried to obtain compound [S2] (amount: 16.9 g, yield: 78%, pale brown crystals).

<Synthesis of additive S3>

[Formula 45]

In tetrahydrofuran (23 g), [DA-5] (1.50 g, 3.80 mmol) was poured, and under ice-cooling, 3-triethoxysilylpropyl isocyanate (1.98 g) was converted into tetrahydrofuran (7 g). The diluted solution was added dropwise over 5 minutes. After the dropwise addition was completed, the mixture was stirred at room temperature for 18 hours and then stirred at 50°C for 3 hours. Since the intermediate body remained, 3-triethoxysilylpropyl isocyanate (0.38 g) was further added, and it stirred at 50 degreeC for 21 hours. Then, 3-triethoxysilylpropyl isocyanate (0.09 g) was further added, and it stirred at 50 degreeC for 6 hours. The reaction solution was concentrated under reduced pressure, the inner volume was adjusted to 10 g, and then acetonitrile (15 g) was added and stirred at room temperature to precipitate crystals. The precipitated crystal was filtered and the filtrate was dried to obtain compound [S3] (amount: 3.0 g, yield: 89%, pale purple crystal).

<Synthesis of additive S4>

[Chemical Formula 46]

In acetonitrile (30 g), 1,4-phenylenediisocyanate (1.98 g, 12.3 mmol) was poured, and at room temperature, 3-aminopropyltriethoxysilane (4.82 g) was converted into acetonitrile (10 g). The diluted solution was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was stirred at room temperature for 18 hours. In the meantime, acetonitrile (90 g) was added because stirring became poor. After confirming completion of the reaction by NMR, the precipitated crystal was filtered and the filtrate was dried to obtain compound [S4] (amount: 6.3 g, yield: 94%, white crystal).

<Viscosity>

The viscosity of the polymer solution in the following synthesis example was obtained using an E-type viscometer TVE-22H (manufactured by Toki Industries, Inc.) at a sample amount of 1.1 ml, a cone rotor TE-1 (1° 34', R24), and a temperature of 25°C. Measured.

(Synthesis Example 1)

In a 200 ml four-neck flask with a stirring device and a nitrogen introduction tube, DA-1 (4.03 g, 16.5 mmol), DA-2 (3.59 g, 9.0 mmol), and DA-3 (2.51 g, 4.5 mmol) was added, then NMP (74.0 g) was added, followed by stirring and dissolving while sending nitrogen. While stirring this solution, CA-1 (4.37 g, 19.5 mmol) and 9.0 g of NMP were added, and it stirred under 40 degreeC conditions for 3 hours. Thereafter, CA-2 (1.71 g, 8.7 mmol) and 9.0 g of NMP were added under the condition of 25° C., and then stirred for 12 hours to obtain a polyamic acid solution (viscosity of 480 mPa·s). The molecular weight of this polyamic acid was Mn = 10,660 and Mw = 20,512.

After 80.0 g of this polyamic acid solution was aliquoted and 20.0 g of NMP was added, 6.8 g of acetic anhydride and 1.8 g of pyridine were added, followed by reaction at 50°C for 3 hours. The reaction solution was poured into 434.4 g of methanol while stirring, and the precipitated precipitate was separated by filtration. Methanol wash|cleaned this deposit, it dried under reduced pressure at 60 degreeC, and obtained the powder of polyimide. The imidation ratio of this polyimide was 75 %. A polyimide solution (SPI-A1) was obtained by adding 80.0 g of NMP to 20.0 g of the obtained polyimide powder, stirring and dissolving at 70°C for 20 hr.

[Examples 1 to 3] and [Comparative Examples 1 to 2]

The polyamic acid solution obtained in Synthesis Example 1 was stirred so that the solvent in the obtained liquid crystal aligning agent became the composition shown in Table 1, adding the solvent and additives S1, S2, or S3, and further stirring at room temperature for 2 hours to The orientation agent was obtained.

*1: The content (part by weight) of each polymer relative to 100 parts by weight of all polymers in the liquid crystal aligning agent is shown.

*2: The content (part by weight) of each additive with respect to 100 parts by weight of all polymers in the liquid crystal aligning agent is shown.

*3: The content (part by weight) of each solvent relative to 100 parts by mass of the liquid crystal aligning agent is shown.

Below, the manufacturing method of the liquid crystal cell for evaluating the relaxation characteristic of accumulated electric charge, the flicker characteristic, and liquid crystal orientation is shown.

A liquid crystal cell provided with the structure of a liquid crystal display element of the FFS system is produced. First, a substrate to which an electrode is attached was prepared. The substrate is a glass substrate having a length of 30 mm, a width of 35 mm, and a thickness of 0.7 mm. On the substrate, the IZO electrode constituting the counter electrode as the first layer is formed on the entire surface. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by the CVD method is formed. The second layer of SiN film has a thickness of 500 nm, and functions as an interlayer insulating film. On the second-layer SiN film, as a third layer, a comb-tooth-shaped pixel electrode formed by patterning an IZO film is disposed to form two pixels, a first pixel and a second pixel. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-tooth-shaped shape formed by arranging a plurality of "k"-shaped electrode elements with a central portion bent. The width of each electrode element in the width direction is 3 μm, and the spacing between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is configured by arranging a plurality of electrode elements having a “ku” shape with a central portion bent, the shape of each pixel is not a rectangular shape, but at the center portion in the same manner as the electrode element. It has a shape similar to a curved, bold, “ku ruler”. And, each pixel is divided up and down with the central bent portion as a boundary, and has a first area on the upper side of the bent portion and a second area on the lower side.

When the first region and the second region of each pixel are compared, the formation directions of electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment layer described later is taken as a reference, the electrode element of the pixel electrode is formed to form an angle of +10° (clockwise direction) in the first region of the pixel, and the pixel electrode in the second region of the pixel The electrode elements of are formed to achieve an angle of -10° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotational motion (in-plane switching) of the liquid crystal in the substrate surface caused by the application of a voltage between the pixel electrode and the counter electrode are opposite to each other. It is structured to be.

Next, the liquid crystal aligning agent obtained in Examples and Comparative Examples was filtered through a filter having a pore diameter of 1.0 µm, and then applied to the prepared substrate with the electrode by spin coat application. After drying for 2 minutes on an 80 degreeC hot plate, it baked for 20 minutes in a 230 degreeC hot air circulation type oven, and obtained the polyimide film with a film thickness of 60 nm. Rubbing this polyimide film with rayon cloth (roller diameter: 120 mm, roller rotation speed: 500 rpm, movement speed: 30 mm/sec, press fit length: 0.3 mm, rubbing direction: 10° inclined to the third layer IZO comb electrode Orientation) After washing|cleaning by ultrasonic irradiation for 1 minute in pure water, water droplets were removed by air blow. Then, it dried at 80 degreeC for 15 minutes, and the board|substrate with a liquid crystal aligning film was obtained. In addition, as a counter substrate, a polyimide film was formed in the same manner as above on a glass substrate having a columnar spacer having a height of 4 μm on which an ITO electrode was formed on the back surface, and orientation treatment was performed in the same procedure as above. A substrate with a liquid crystal aligning film was obtained. One set of substrates with these two liquid crystal alignment films attached, and a sealant was printed on the substrate in the form of leaving a liquid crystal injection hole, and the other one substrate was placed so that the liquid crystal alignment film faces facing each other and the rubbing direction is parallel to each other. And adhered. Thereafter, the sealing agent was cured to prepare an empty cell having a cell gap of 4 μm. Liquid crystal MLC-3019 (manufactured by Merck) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell of the FFS system. After that, the obtained liquid crystal cell was heated at 120°C for 1 hour and left at 23°C overnight, and then used for evaluation of liquid crystal orientation.

<Reduction characteristics of accumulated charge>

The liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are perpendicular to each other, and the pixel electrode and the counter electrode are short-circuited to make the same top, and the LED backlight is irradiated from the bottom of the two polarizing plates, and on the two polarizing plates. The angle of the liquid crystal cell was adjusted so that the luminance of the transmitted light of the LED backlight to be measured was minimized.

Next, while applying a square wave with a frequency of 30 Hz to this liquid crystal cell, the V-T characteristic (voltage-transmittance characteristic) under a temperature of 23°C was measured, and an AC voltage at which the relative transmittance was 23% was calculated. Since this AC voltage corresponds to a region in which the luminance changes with respect to the voltage is large, it is suitable for evaluating the accumulated charge through luminance.

Next, under a temperature of 23°C, an alternating current voltage having a relative transmittance of 23% and a square wave having a frequency of 30 Hz was applied for 5 minutes, and then a DC voltage of +1.0 V was superimposed and driven for 30 minutes. Thereafter, the DC voltage was turned off, and only a square wave having a relative transmittance of 23% and a frequency of 30 Hz was applied for 15 minutes.

The faster the relaxation of the accumulated charge is, the faster the charge accumulation in the liquid crystal cell when the DC voltage is superimposed. Therefore, the relaxation characteristic of the accumulated charge decreases by 2% or more from the relative transmittance immediately after the DC voltage is superimposed. It was evaluated as the required time until. That is, when the relative transmittance decreases by 2% or more within 30 minutes, it is defined as "good", and when the relative transmittance does not decrease by 2% or more even after 30 minutes has passed, it is defined as "defective" and evaluated.

<Evaluation of liquid crystal orientation>

Using this liquid crystal cell, an AC voltage of 9 VPP was applied for 190 hours at a frequency of 30 Hz in a constant temperature environment at 60°C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and left as it is at room temperature for one day.

After standing, the liquid crystal cell was provided between two polarizing plates arranged so that the polarization axes were orthogonal, the backlight was turned on in a state where no voltage was applied, and the arrangement angle of the liquid crystal cell was adjusted so that the luminance of the transmitted light became the smallest. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel becomes darkest to the angle at which the first region becomes darkest was calculated as the angle Δ. Similarly for the second pixel, the second region and the first region were compared to calculate the same angle Δ. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of this liquid crystal cell was less than 0.2 degrees, it was defined as "good", and when the value of the angle Δ was 0.2 degrees or more, it was defined and evaluated as "defective".

<Evaluation of voltage retention rate (VHR)>

A voltage of 1 V was applied to the obtained liquid crystal cell for 60 µs at a temperature of 60°C, and the voltage after 50 ms was measured, and how much the voltage could be maintained was calculated as a voltage retention rate. In addition, voltage retention measurement device VHR-1 manufactured by Toyo Technica was used for the measurement of the voltage retention rate.

<Evaluation of optical properties (transparency)>

A quartz substrate having a length of 40 mm, a width of 40 mm, and a thickness of 1.0 mm was prepared. Next, after filtering the liquid crystal aligning agent with a 1.0 micrometer filter, it spin-coats on the said quartz substrate. Subsequently, after drying for 2 minutes on an 80 degreeC hot plate, it baked at 230 degreeC for 20 minutes, and obtained the polyimide film with a film thickness of 100 nm on each board|substrate.

The evaluation of transparency was performed by measuring the transmittance of the substrate obtained by the above method. Specifically, UV-3600 (manufactured by Shimadzu Corporation) was used as a measuring device, and the transmittance was measured under the conditions of a temperature of 25°C and a scanning wavelength of 300 to 800 nm. At that time, it was carried out using a quartz substrate to which nothing was applied as a reference (reference example). In the evaluation, the average transmittance at a wavelength of 400 to 800 nm was calculated, and the higher the transmittance, the better the transparency.

<Evaluation result>

About the liquid crystal display element using each liquid crystal aligning agent of said Examples 1-3 and Comparative Examples 1-2, the evaluation of the afterimage erasing time performed above, stability evaluation of liquid crystal orientation, and evaluation of transparency are shown in Table It is shown in 2.

*1: The content (part by weight) of each polymer relative to 100 parts by weight of all polymers in the liquid crystal aligning agent is shown.

*2: The content (part by weight) of each additive with respect to 100 parts by weight of all polymers in the liquid crystal aligning agent is shown.

As shown in Table 2, it can be seen that the liquid crystal display elements using the liquid crystal aligning agent of Examples 1-3 have excellent voltage retention, quick relaxation of accumulated charge, and good liquid crystal alignment and transparency.

Industrial availability

The liquid crystal aligning agent of the present invention is widely used in a vertical electric field system such as a TN system and a VA system, in particular, a transverse electric field system such as an IPS system and an FFS system, for a liquid crystal display device.

In addition, the specification of Japanese Patent Application No. 2018-51091, the claims, and the entire contents of the abstract for which it applied on March 19, 2018 is cited here, and it is taken as an indication of the specification of the present invention.

Claims (12)

A liquid crystal aligning agent containing the following (A) component, (B) component, and an organic solvent.
Component (A): at least one polymer selected from the group consisting of a polyimide precursor having a structure represented by the following formula (2) and an imidized polymer of the polyimide precursor

However, in formula (2), R ⁵ is a single bond or a divalent organic group. R ⁶ is a structure represented by -(CH ₂ ) _n -, and arbitrary -CH ₂ -may be substituted with a bond selected from ether, ester and amide under conditions that are not adjacent to each other. R ⁷ is a single bond or a divalent organic group. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group. n is an integer of 2-20.
(B) component: compound represented by following formula (1)

However, in formula (1), Q ¹ and Q ² are each independently one species selected from the following (Q1-1), (Q1-2) and single bonds, but in formula (1), Q ¹ and Q At least one of ² is one species selected from (Q1-1) and (Q1-2). R ¹ is a hydrogen atom or a monovalent organic group.

q1 and q2 are each independently 0 or 1.
L ¹ and L ² are hydrogen atoms. However, when Q ¹ is (Q1-1), L ¹ and L ² may become one to form a single bond.
S ¹ and S ² are each independently a group represented by the following formula (S).

However, in formula (S), R ² is a hydrogen atom or an alkyl group. L is an alkylene having 2 to 20 carbon atoms. R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or an alkynyl group having 2 to 4 carbon atoms. q represents a natural number of 1 to 3. * Represents a bond to formula (1). The method of claim 1,
The liquid crystal aligning agent in which the said (A) component contains at least 1 type of polymer selected from the polyimide precursor containing the structural unit represented by following formula (3), and the imide polymer of the polyimide precursor.

However, in formula (3), X ³ is a tetravalent organic group derived from a tetracarboxylic acid derivative. Y ³ is a divalent organic group derived from a diamine containing the structure of formula (2). R ¹³ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The method of claim 2,
The liquid crystal aligning agent containing 20-100 mol% of the structural unit represented by the said formula (3) with respect to the said polyimide precursor all the structural units which it has. The method according to any one of claims 1 to 3,
The liquid crystal aligning agent in which the component (B) is at least one compound selected from the group consisting of the following (B-1) to (B-9).
(B-1): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-1), L ¹ and L ² are a hydrogen atom,
(B-2): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-1), L ¹ and L ² become one to form a single bond,
(B-3): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is (Q1-1), and L ¹ and L ² are hydrogen atoms. compound,
(B-4): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is a single bond, L ¹ and L ² are a hydrogen atom,
(B-5): In the above formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is (Q1-1), and L ¹ and L ² become one Compounds that are single bonds,
(B-6): In the formula (1), q1 and q2 are 1, Q ¹ is a single bond, Q ² is (Q1-1), L ¹ and L ² are a hydrogen atom,
(B-7): In the above formula (1), q1 and q2 are 1, Q ¹ is (Q1-1), Q ² is a single bond, and L ¹ and L ² become one to be a single bond. compound,
(B-8): In the formula (1), q1 and q2 are 0, Q ¹ is (Q1-2), and L ¹ and L ² are hydrogen atoms.
(B-9): In the formula (1), q1 and q2 are 1, Q ¹ is (Q1-2), and L ¹ and L ² are a hydrogen atom. The method according to any one of claims 1 to 3,
The liquid crystal aligning agent in which the component (B) is at least one compound selected from the group consisting of the following formulas B-1-1 to B-9-1.

The method according to any one of claims 1 to 5,
The organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone , 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, or 4-hydroxy-4-methyl-2-pentanone liquid crystal aligning agent. The method of claim 6,
The liquid crystal aligning agent containing the solvent which the said organic solvent improves the coating film property and surface smoothness of a liquid crystal aligning film when the liquid crystal aligning agent is applied. The method according to any one of claims 1 to 7,
A liquid crystal aligning agent containing 1-10 mass% of a polymer containing said (A) component in a liquid crystal aligning agent. The method according to any one of claims 1 to 8,
A liquid crystal aligning agent containing 0.1-20 mass% of said (B) component with respect to said (A) component. A liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of Claims 1-9. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10. The method of claim 11,
A liquid crystal display device in which the display device is a horizontal electric field system.