KR20210099569A - Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element using same - Google Patents

Abstract

A liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element from which relaxation of an accumulation|storage electric charge is quick and the liquid crystal aligning film with a small accumulation amount of electric charge can be obtained is provided.
The liquid crystal aligning agent containing a following polymer (A) and a polymer (B). Polymer (A): A polymer obtained by reaction of a tetracarboxylic-acid derivative component, and the diamine component containing the diamine shown in following formula (1), and the diamine shown in following formula (2). Polymer (B): A polymer obtained by reaction of a tetracarboxylic-acid derivative component and the diamine component containing at least 1 sort(s) of the diamine represented by following formula (3). Stage, Y ₂ is a divalent organic group having a nitrogen atom or nitrogen-containing aromatic heterocyclic ring which is bonded to the aromatic.

Description

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

This invention relates to a liquid crystal display element provided with a liquid crystal aligning agent, the liquid crystal aligning film obtained by this liquid crystal aligning agent, and the obtained liquid crystal aligning film.

DESCRIPTION OF RELATED ART Liquid crystal display elements are widely used as display parts, such as a personal computer, a cellular phone, a smart phone, and a television. The liquid crystal display element 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, a liquid crystal alignment film for controlling alignment of liquid crystal molecules in the liquid crystal layer, a pixel electrode A thin film transistor (TFT) for switching the electrical signal supplied to the device is provided. As a driving method of liquid crystal molecules, a longitudinal electric field system, such as a TN system and a VA system, and a transverse electric field system, such as an IPS system and an FFS system, are known. Among these, the transverse electric field system in which liquid crystal molecules are switched in parallel to the substrate has a wide viewing angle characteristic compared to the vertical electric field system and is known as a liquid crystal display element capable of high-quality display.

As a factor affecting the display quality of a liquid crystal element, the voltage retention of a liquid crystal cell, charge accumulation|storage characteristic, etc. are known with the uniformity of liquid crystal orientation. For example, when the voltage retention is low, a sufficient voltage is not applied to the liquid crystal, and the display contrast is lowered. Moreover, when an electric charge accumulates in a liquid crystal cell, the orientation of a liquid crystal is disturbed, or phenomena, such as an afterimage and burn-in, occur, and the display quality of a liquid crystal element is reduced remarkably.

In particular, in the transverse electric field method, compared to the vertical electric field method, the voltage retention rate is easily lowered because there are fewer electrode portions formed in the substrate, or a strong electric field acts on the alignment film or the liquid crystal layer due to the close distance between the pixel electrode and the common electrode. As a result, problems due to insufficient voltage retention or charge accumulation characteristics, such as easy charge accumulation, are likely to become significant. In addition, in the transverse electric field system, if the alignment control force of the liquid crystal is weak, the liquid crystal does not return to the initial alignment state when the liquid crystal is driven for a long time, and the contrast decreases or causes an afterimage, so the alignment control force of the liquid crystal alignment film is also important. .

The method of using the liquid crystal aligning film obtained from the liquid crystal aligning agent which mixed the polymer of high orientation and the polymer of low resistance with respect to the subject of the above transverse electric field system is proposed (patent document 1).

International Publication No. WO2004/53583 pamphlet

The characteristic calculated|required of a liquid crystal aligning film is becoming strict with performance improvement of a liquid crystal display element. In particular, the FFS method has a structure in which charges are easily accumulated in the liquid crystal cell and the accumulated charges are difficult to escape even compared to the IPS method of the same transverse electric field method. Characteristics such as fast speed are also becoming important. Moreover, since the FFS system has a larger electric field intensity than the IPS system, the request|requirement regarding the orientation regulating force of a liquid crystal is also strict.

Based on the above, the present invention can obtain a liquid crystal aligning film suitable for use in a liquid crystal display device of a transverse electric field system, particularly an FFS system, and furthermore, a liquid crystal aligning film having a small amount of charge accumulated and a quick relaxation of the accumulated charge even in the FFS system. It makes it a subject to provide the liquid crystal aligning agent which exists.

MEANS TO SOLVE THE PROBLEM The present inventors discovered that the said objective could be achieved by invention of the following summary, as a result of repeating earnest examination for the said objective achievement.

The liquid crystal aligning agent containing a following polymer (A) and a polymer (B).

Polymer (A): A polymer obtained by reaction of a tetracarboxylic-acid derivative component, and the diamine component containing the diamine shown in following formula (1), and the diamine shown in following formula (2).

[Formula 1]

[Formula 2]

Polymer (B): A polymer obtained by reaction of a tetracarboxylic-acid derivative component and the diamine component containing at least 1 sort(s) of the diamine represented by following formula (3).

[Formula 3]

(Y ₂ is a divalent organic group having a nitrogen atom or nitrogen-containing aromatic heterocyclic ring bonded to an aromatic)

ADVANTAGE OF THE INVENTION According to this invention, the display performance improvement of the display performance of the liquid crystal display element of a transverse electric field system, especially the accumulation|storage amount of the electric charge in the liquid crystal display element of an FFS system is small, and relaxation|relief of the accumulated electric charge is quick, etc. can be achieved.

Both of the polymer (A) and the polymer (B) used for this invention are polymers obtained by reaction of a tetracarboxylic-acid derivative component and a diamine component together.

Examples of the tetracarboxylic acid derivative include tetracarboxylic acid dianhydride, tetracarboxylic acid disilyl ester, tetracarboxylic acid dichloride, tetracarboxylic acid dialkyl ester, tetracarboxylic acid dialkenyl ester, and tetracarboxylic acid dialkyl ester. dichloride; and the like.

As an example of the polymer obtained by reaction of a tetracarboxylic-acid derivative component and a diamine component, polyamic acid, polyamic acid ester, the polyimide which is the imidation polymer of the said polyamic acid or polyamic acid ester, etc. are mentioned. The reaction conditions for producing these polymers, etc. are not specifically limited, A well-known method can be used.

The polymer used for this invention may be the polymer which modified the principal chain terminal using the compound which is monofunctional with respect to a tetracarboxylic-acid derivative component and/or a diamine component. As the monofunctional compound, a monoamine, a monoisocyanate, the compound which has one acid anhydride group, the compound which has one acid chloride group, etc. are mentioned.

In the present invention, "tetracarboxylic acid residue" is a structure derived from the tetracarboxylic acid derivative component, and is a tetravalent structure excluding four carboxyl groups of the tetracarboxylic acid derivative or a group derived from the carboxyl group. means In addition, a "diamine residue" is a structure derived from the said diamine component, and means the bivalent structure except the two amino groups which diamine has.

<Polymer A>

A polymer (A) is a polymer obtained by (polycondensation) reaction of a tetracarboxylic-acid derivative component, and the diamine component containing the diamine shown in following formula (1), and the diamine shown in following formula (2).

[Formula 4]

[Formula 5]

The diamine residue in a polymer (A) has at least 2 types of structures of the diamine residue derived from the diamine of Formula (1), and the diamine residue derived from the diamine of Formula (2).

In a polymer (A), the diamine residue derived from the diamine of Formula (1) is preferable in it being 10 mol% or more of all the diamine residues which a polymer (A) has, More preferably, it is 20 mol% or more. Moreover, in a polymer (A), the diamine residue derived from the diamine of Formula (2) is preferable in it being 30 mol% or more of all the diamine residues which a polymer (A) has, More preferably, it is 40 mol% or more.

The polymer (A) may have a diamine residue derived from another diamine other than the diamine of Formula (1) and Formula (2). As another diamine, the diamine (However, the diamine of Formula (1) and Formula (2) is excluded) represented by following formula (4) is mentioned.

[Formula 6]

In Formula (4), Y<_1> represents a divalent organic group, and two R represents a hydrogen atom or a C1-C5 alkyl group each independently.

Although (Y1-1) - (Y1-18) which are preferable specific examples _{of Y<1>} in Formula (4) are shown below, this invention is not limited to these.

[Formula 7]

[Formula 8]

[Formula 9]

When the polymer (A) has a diamine residue derived from a diamine other than the diamine of the formulas (1) and (2), a diamine residue derived from the diamine of the formula (1) and a diamine derived from the diamine of the formula (2) It is preferable that the sum total of a diamine residue has 50 mol% or more of all the diamine residues which a polymer (A) has, More preferably, it is 60 mol% or more.

Moreover, when the liquid crystal aligning agent of this invention is apply|coated to a board|substrate, from a viewpoint that liquid-crystal orientation improves because a polymer (A) becomes easy to be unevenly distributed in surface layer vicinity of a liquid crystal aligning film, as said other diamine, in said Formula (4) It is preferable to use at least 1 sort(s) of the diamine which Y<_{1> in following has a structure of following formula (5).}

[Formula 10]

In the formula (5), D represents a protecting group which is preferably removed by heating at 80 to 250°C, particularly preferably 80 to 230°C and is substituted with a hydrogen atom, and * represents a connection point with another structure. Preferred examples of D include a t-butoxycarbonyl group.

Although (5-1) - (5-9) which are preferable specific examples of _Y<1> which have a structure of Formula (5) below are mentioned, this invention is not limited to these. In addition, Boc in the following structure represents a t-butoxycarbonyl group.

[Formula 11]

In a polymer (A), 1-40 mol% of all the diamine residues which a polymer (A) has as for the residue of diamine represented by Formula (4) is preferable, More preferably, it is 5-30 mol%.

The structure of the tetracarboxylic acid residue in a polymer (A) is not specifically limited. In addition, the number of structures of the tetracarboxylic-acid residue which a polymer (A) has may be one, and two or more types may be mixed.

Although (A-1) - (A-21) which are preferable structures of the tetracarboxylic-acid residue in a polymer (A) are shown below, this invention is not limited to these.

[Formula 12]

[Formula 13]

Although the molecular weight of a polymer (A) is not specifically limited as long as a favorable coating film can be formed, For example, 2,000-500,000 are preferable in a weight average molecular weight, More preferably, it is 5,000-300,000, More preferably, it is 10,000- 100,000. Moreover, the number average molecular weight becomes like this. Preferably it is 1,000-250,000, More preferably, it is 2,500-150,000, More preferably, it is 5,000-50,000.

<Polymer B>

A polymer (B) is a polymer obtained by reaction of a tetracarboxylic-acid derivative component and the diamine component containing at least 1 sort(s) of the diamine represented by following formula (3).

[Formula 14]

In Formula (3), Y<_2> is a divalent organic group which has a nitrogen atom couple|bonded with an aromatic group, or a nitrogen-containing aromatic heterocyclic ring.

Represents a phosphorus (Y2-1) ~ (Y2-14), in particular the structure of the preferred Y ₂ in the following, the invention is not limited to these.

[Formula 15]

[Formula 16]

Polymer (B) is a diamine moiety having the structure, and even one kind, even if two or more are mixed, but at least one is a structure of Y ₂ in the formula (3).

In the polymer (B), the structure of the diamine residue Y ₂ is, if the polymer (B) is more than 50 mol% of the total diamine residue which is preferred, and more preferably at least 60 mol%.

The polymer (B) may have a diamine residue derived from other diamines other than the diamine represented by Formula (3). As such other diamine, the compound represented by the said Formula (4) which is another diamine in a polymer (A) (however, the diamine represented by Formula (3) is excluded) can be used. The usage-amount of other diamine in this case is also the same as that in the case of a polymer (A).

The structure of the tetracarboxylic acid residue in a polymer (B) is not specifically limited. In addition, the number of structures of the tetracarboxylic-acid residue which a polymer (B) has may be one, and two or more types may be mixed.

Although the preferable structure shown by the polymer (A) is mentioned as a preferable structure of the tetracarboxylic-acid residue in a polymer (B), this invention is not limited to these.

Although the molecular weight of a polymer (B) is not specifically limited as long as a favorable coating film can be formed, For example, 2,000-500,000 are preferable in a weight average molecular weight, More preferably, it is 5,000-300,000, More preferably, 10,000 ~ 100,000. Moreover, the number average molecular weight becomes like this. Preferably it is 1,000-250,000, More preferably, it is 2,500-150,000, More preferably, it is 5,000-50,000.

<Liquid crystal aligning agent>

Although the content rate of the polymer (A) and polymer (B) in the liquid crystal aligning agent of this invention is not specifically limited, Content of a polymer (A) is 10- with respect to the total amount of a polymer (A) and a polymer (B) 50 mass % is preferable, More preferably, it is 20-40 mass %. That is, 90-50 mass % is respectively preferable with respect to the total amount of a polymer (A) and a polymer (B), and, as for content of a polymer (B), it is more preferable that it is 80-60 mass %.

The liquid crystal aligning agent of this invention may contain other polymers other than a polymer (A) and a polymer (B). Although other polymers are not specifically limited, For example, polyamic acid, polyamic acid ester, polyimide, polysiloxane, polyester, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene maleimide) derivative, poly(meth)acryl and polymers having a main skeleton of a rate or the like.

The liquid crystal aligning agent of this invention may contain components other than a polymer. As components other than the polymer, a dielectric or conductive material for the purpose of changing electrical properties such as dielectric constant and conductivity of the liquid crystal aligning film, a silane coupling agent for the purpose of improving the adhesion between the liquid crystal aligning film and the substrate, the hardness of the film when the liquid crystal aligning film is used or an imidation accelerator for the purpose of efficiently advancing imidization of a polyamic acid when a crosslinking compound for the purpose of increasing the density or a coating film is fired, and the like.

The liquid crystal aligning agent of this invention is used in order to produce a liquid crystal aligning film, It is preferable that it is the coating liquid which melt|dissolved said component in the organic solvent from a viewpoint of forming a uniform thin film. The density|concentration of a coating liquid is changed suitably according to the thickness of the coating device to be used, and the liquid crystal aligning film to be obtained. It is preferable that it is 1 mass % or more from the point of forming a uniform and defect-free coating film, and it is preferable to set it as 10 mass % or less from the point of storage stability of a solution. A particularly preferred concentration of the polymer is 2 to 8 mass%.

The organic solvent used for the said coating liquid will not be specifically limited if a polymer component melt|dissolves uniformly. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyro and lactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, and cyclopentanone. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferable. These solvents may use 2 or more types together.

Moreover, in the composition aiming at coating-film formation, it is common to use the mixed solvent which added the solvent which improves applicability|paintability improvement and the smoothness of the coating-film surface in addition to the above solvents, Also in the liquid crystal aligning agent of this invention Such a mixed solvent is preferably used. Although the specific example of the organic solvent to mix is given below, 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, 4-hydroxy-4-methyl-2-penta Non, 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 diacetate Yite, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol Monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3 -Ethyl methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionate butyl, lactate methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactate isoamyl The solvent etc. which are shown by ester and following formula [D-1] - [D-3] are mentioned.

[Formula 17]

(R in formula [D-1] and formula [D-2] represents a C1-C3 alkyl group, R in formula [D-3] represents a C1-C4 alkyl group.)

Among the above, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2- Pentanone, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether is preferable. The kind and content of such a solvent are suitably selected according to the coating apparatus of a liquid crystal aligning agent, application|coating conditions, application|coating environment, etc. In addition, these solvents may use 2 or more types together.

<Liquid crystal alignment film>

The liquid crystal aligning film of this invention is obtained from the said liquid crystal aligning agent of this invention. To give an example of a method of obtaining a liquid crystal aligning film from a liquid crystal aligning agent, a liquid crystal aligning agent in the form of a coating liquid is applied to a substrate, dried, and the film obtained by baking is subjected to alignment treatment by a rubbing treatment method or a photo-alignment treatment method. can be heard

It does not specifically limit as a board|substrate which apply|coats a liquid crystal aligning agent, Plastic substrates, such as a glass substrate, a silicon nitride board|substrate, an acryl board|substrate, and a polycarbonate board|substrate, etc. can also be used. In that case, it is preferable from the point of simplification of a process to use the board|substrate with which the ITO electrode etc. for driving a liquid crystal were formed. In the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as it is a single-side substrate, and a material that reflects light such as aluminum can also be used for the electrode in this case.

Although the application method of a liquid crystal aligning agent is not specifically limited, Industrially, screen printing, an offset printing, a flexographic printing, the inkjet method, etc. are common. As another coating method, there exist a dip method, the roll coater method, the slit coater method, the spinner method, the spray method, etc., You may use these according to the objective.

After apply|coating a liquid crystal aligning agent on a board|substrate, with heating means, such as a hot plate, a heat circulation type oven, and IR (infrared) type|mold oven, a solvent is evaporated and it bakes. Drying after apply|coating a liquid crystal aligning agent, and a baking process can select arbitrary temperature and time. Usually, in order to fully remove the solvent to contain, it bakes at 50-120 degreeC for 1 to 10 minutes, and then, the conditions to bake at 150-300 degreeC for 5 to 120 minutes are mentioned.

Although the thickness of the liquid crystal aligning film after baking is not specifically limited, Since reliability of a liquid crystal display element may fall when too thin, 5-300 nm is preferable and 10-200 nm is more preferable.

The liquid crystal aligning film of this invention is suitable as a liquid crystal aligning film of the liquid crystal display element of transverse electric field systems, such as an IPS system and an FFS system, Especially useful as a liquid crystal aligning film of the liquid crystal display element of an FFS system.

<Liquid crystal display element>

After obtaining the board|substrate with the liquid crystal aligning film obtained from the said liquid crystal aligning agent, the liquid crystal display element of this invention manufactures a liquid crystal cell by a known method, and sets it as an element using the liquid crystal cell.

Although an example of the manufacturing method of a liquid crystal cell is given below, this invention is not limited to this.

First, a set of board|substrates in which the electrode for driving a liquid crystal was formed is prepared. This electrode can be set as, for example, an ITO electrode, and is patterned so that a desired image display may be performed. Moreover, switching elements, such as TFT (Thin Film Transistor), may be formed in each pixel part which comprises an image display. A liquid crystal aligning film is formed on this board|substrate as mentioned above.

Next, after arranging, for example, an ultraviolet curable sealing material in a predetermined place on one of the two substrates on which the liquid crystal aligning film was formed, and arranging the liquid crystal in several predetermined places on the surface of the liquid crystal aligning film, the liquid crystal aligning film is A liquid crystal cell is obtained by irradiating an ultraviolet-ray to the whole surface of a board|substrate and hardening a sealing material, after pushing a liquid crystal to the liquid crystal aligning film whole surface by bonding and crimping|bonding so that it may oppose and a liquid crystal aligning film whole surface.

In addition, as a process after forming a liquid crystal aligning film on a board|substrate, when arrange|positioning a sealing material in a predetermined place on one board|substrate, the opening part which can be filled with a liquid crystal from the outside is formed, and the board|substrate is bonded together without arrange|positioning a liquid crystal. Then, a liquid crystal material is inject|poured into a liquid crystal cell through the opening part provided in the sealing material, then, this opening part is sealed with an adhesive agent, and a liquid crystal cell is obtained. A vacuum injection method may be sufficient for injection|pouring of a liquid crystal material, and the method using capillary phenomenon in air|atmosphere may be sufficient.

In any of the above methods, in order to secure the space in which the liquid crystal material is filled in the liquid crystal cell, columnar projections are formed on one substrate, the spacers are dispersed on the one substrate, or the spacers are mixed in the sealing material, Or it is preferable to take measures, such as combining these.

As said liquid crystal material, a nematic liquid crystal and a smectic liquid crystal are mentioned, Among them, a nematic liquid crystal is preferable, and either a positive liquid crystal material and a negative liquid crystal material may be used. Next, a polarizing plate is installed. Specifically, it is preferable to affix a pair of polarizing plates on the surface on the opposite side to the liquid crystal layer of two board|substrates.

Example

Hereinafter, although an Example etc. are given and demonstrated concretely about this invention, this invention is not limited to these Examples. In addition, the abbreviation of the compound and solvent in the following is as follows.

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

CA-1 to CA-4: each compound of the following structural formula, DA-1 to DA-6: each compound of the following structural formula

AD-1: 3-glycidoxypropyltriethoxysilane, AD-2: a compound of the following structural formula

[Formula 18]

[Formula 19]

[Formula 20]

[Measurement of viscosity]

The viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Industries, Ltd.) at a sample amount of 1.1 mL, cone rotor TE-1 (1°34', R24), and a temperature of 25°C.

<Synthesis of polymer>

(Synthesis Example 1)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, 2.86 g (10.0 mmol) of DA-1, 1.47 g (6.0 mmol) of DA-2, and 1.59 g (4.0 mmol) of DA-3 were weighed into , NMP was added 53.2g, and it stirred, sending nitrogen, and it was made to melt|dissolve. While stirring this diamine solution under water cooling, 4.20 g (19.3 mmol) of CA-1 is added, 21.0 g of NMP is further added, and the mixture is stirred at 50°C in a nitrogen atmosphere for 12 hours, and polymer solution A-1 (concentration: 12.0) Mass %, viscosity: 496 mPa*s) was obtained.

(Synthesis Example 2)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen inlet tube, 3.19 g (16.0 mmol) of DA-4 and 0.79 g (4.0 mmol) of DA-5 are weighed, 49.0 g of NMP is added, and nitrogen is sent It was dissolved by stirring. While stirring this diamine solution under water cooling, 2.59g (13.2mmol) of CA-2 was added, 13.9g of NMPs were further added, and it stirred at 23 degreeC in nitrogen atmosphere for 2 hours and a half. Then, while stirring this solution under water cooling, 1.20 g (4.0 mmol) of CA-3 was added, 7.0 g of NMP was further added, and the mixture was stirred at 23° C. in a nitrogen atmosphere for 12 hours, and then polymer solution B-1 (concentration). : 10.0 mass %, viscosity: 165 mPa*s) was obtained.

(Synthesis Example 3)

3.67 g (18.4 mmol) of DA-4 and 0.70 g (4.6 mmol) of DA-6 were weighed into a 100 mL eggplant flask equipped with a stirring device and a nitrogen introduction tube, 26.8 g of NMP was added, and nitrogen was sent It was dissolved by stirring. While stirring this diamine solution under water cooling, CA-2 was added 2.94g (15.0mmol), 14.5g of NMPs were further added, and it stirred at 23 degreeC in nitrogen atmosphere for 30 minutes. Thereafter, while stirring this solution under water cooling, 1.44 g (5.8 mmol) of CA-4 is added, and further, 8.2 g of NMP is added, and the mixture is stirred at 50° C. in a nitrogen atmosphere for 12 hours, and polymer solution B-2 (concentration) : 15.0 mass %, viscosity: 352 mPa*s) was obtained.

(Synthesis Example 4)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen introduction tube, 3.19 g (16 mmol) of DA-4 and 0.79 g (4 mmol) of DA-5 are weighed, 54.4 g of NMP is added, and nitrogen is sent It was dissolved by stirring. 0.90 g (4.6 mmol) of CA-2 was added, stirring this diamine solution under water cooling, 15.5 g of NMPs were further added, and it stirred at 23 degreeC in nitrogen atmosphere for 30 minutes. Thereafter, while stirring this solution under water cooling, CA-4 was added 3.75 g (15.0 mmol), NMP was further added 7.8 g, and the mixture was stirred in a nitrogen atmosphere at 50° C. for 12 hours, and then polymer solution B-3 (concentration). : 10.0 mass %, viscosity: 218 mPa*s) was obtained.

(Synthesis Example 5)

5.73 g (20.0 mmol) of DA-1 was weighed into a 100 mL eggplant flask equipped with a stirring device and a nitrogen introduction tube, 56.9 g of NMP was added, and it stirred, sending nitrogen, and it was made to melt|dissolve. While stirring this diamine solution under water cooling, 3.97 g (18.2 mmol) of CA-1 is added, 14.2 g of NMP is further added, and the mixture is stirred at 50°C in a nitrogen atmosphere for 12 hours, and polymer solution C-1 (concentration: 12.0) mass %, viscosity: 505 mPa·s) was obtained.

(Synthesis Example 6)

In a 100 mL eggplant flask equipped with a stirring device and a nitrogen introduction tube, 4.13 g (14.4 mmol) of DA-1 and 1.43 g (3.6 mmol) of DA-3 are weighed, 53.3 g of NMP is added, and nitrogen is sent It was dissolved by stirring. While stirring this diamine solution under water cooling, 3.53 g (16.2 mmol) of CA-1 is added, 13.3 g of NMP is further added, and the mixture is stirred at 50°C in a nitrogen atmosphere for 12 hours, and then polymer solution C-2 (concentration: 12.0). Mass %, viscosity: 498 mPa*s) was obtained.

<Preparation of liquid crystal aligning agent>

Example 1

Using the polymer solution A-1 and the polymer solution B-1, the polymer solution A-1 (7.5 g) and the polymer solution B-1 (21.0 g) were mixed so that the mass ratio of the two types of polymers was 30:70. mixed. To this liquid mixture, an NMP solution (3.0 g) containing 1% by weight of NMP (5.1 g), BCS (12.5 g), AD-1, and an NMP solution (0.9 g) containing 10% by weight of AD-2 were added It added, stirring, and the liquid crystal aligning agent of this invention was obtained by stirring at room temperature for 2 hours.

Examples 2, 3, and Comparative Examples 1 to 4

With a composition shown in following Table 1, operation similar to the said Example 1 was performed, and the liquid crystal aligning agent which is Examples 2 and 3 of this invention, and the liquid crystal aligning agent which are Comparative Examples 1-4 were obtained.

<Production of liquid crystal cell>

The FFS drive liquid crystal cell shown below was produced using the liquid crystal aligning agent obtained above.

[Composition of FFS driving liquid crystal cell]

A liquid crystal cell for fringe field switching (FFS) mode is a first glass substrate on which a FOP (Finger on Plate) electrode layer composed of a planar common electrode-insulating layer-comb-shaped pixel electrode is formed on the surface. And the 2nd glass substrate in which the ITO film|membrane for antistatic is formed in the back surface and the columnar spacer of 4 micrometers in height was made into 1 set. The above-described pixel electrode has a comb-tooth shape in which a plurality of electrode elements with a width of 3 μm in which the central portion is bent at an inner angle of 160° are arranged in parallel with an interval of 6 μm, and one pixel is formed of a plurality of electrode elements. It has a first region and a second region with a boundary line connecting the bent portions.

Moreover, when the liquid crystal aligning film formed in a 1st glass substrate orientates so that the direction which divides the inner angle of a pixel bending part into equal parts, and the orientation direction of a liquid crystal may be orthogonal, and the liquid crystal aligning film formed in a 2nd glass substrate manufactures a liquid crystal cell The alignment treatment is performed so that the alignment direction of the liquid crystal on the first substrate coincides with the alignment direction of the liquid crystal on the second substrate.

[Production procedure of liquid crystal cell]

The liquid crystal aligning agent filtered with the filter with a hole diameter of 1.0 micrometer was apply|coated to the surface of each said pair of glass substrates by spin coat application|coating, and it was made to dry for 2 minutes on an 80 degreeC hotplate. Then, it baked for 30 minutes in 230 degreeC hot-air circulation type oven, and obtained the board|substrate with a liquid crystal aligning film with a film thickness of 100 nm. The surface of the substrate on which the liquid crystal aligning film is formed is rubbed with rayon spring (Yoshikawa Chemical Co., Ltd., YA-20R) (Roller diameter: 120 mm, Roller rotation speed: 1000 rpm, Movement speed: 20 mm/sec, Press-fit length: 0.4 mm) After carrying out ultrasonic irradiation for 1 minute in pure water, washing|cleaning and removing water droplets by air blow, it dried at 80 degreeC for 15 minutes and obtained the board|substrate with a liquid crystal aligning film.

Next, a sealing compound is printed on one side of the board|substrate with a liquid crystal aligning film of the said set, and the other board|substrate so that a liquid crystal aligning film surface may face, and each rubbing direction is attached so that it may become antiparallel, and a sealing compound is hardened to produce an empty cell. Liquid crystal MLC-3019 (made by Merck Corporation) was inject|poured into this empty cell by the reduced pressure injection method, the injection port was sealed, and the FFS drive liquid crystal cell was obtained. Then, after heating the obtained liquid crystal cell at 120 degreeC for 1 hour and leaving it to stand overnight, various evaluation was performed.

<Characteristics evaluation of liquid crystal cells>

The characteristics of the liquid crystal cell produced above were evaluated as follows.

[Charge accumulation]

With respect to the FFS driving liquid crystal cell fabricated above, the LED backlight is provided from below the two polarizing plates in a state where it is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the pixel electrode and the counter electrode are short-circuited to bring them to the same potential. It irradiated and adjusted the angle of the liquid crystal cell so that the brightness|luminance of the LED backlight transmitted light measured from the top of 2 polarizing plates might become the minimum. This evaluation was performed on the temperature condition of the state whose temperature of a liquid crystal cell is 23 degreeC.

Next, V-T curve (voltage-transmittance curve) was measured, applying the alternating voltage of frequency 30Hz to this liquid crystal cell, and relative transmittance computed the alternating voltage value used as 23 % and 100 % as a drive voltage. Next, in order to exclude the influence by charging, the alternating voltage of 20 mV was applied at 23 degreeC for the liquid crystal cell by the frequency of 1 kHz for 30 minutes.

Thereafter, an AC voltage having a relative transmittance of 100% was applied for 45 minutes and the minimum offset voltage value was measured every 3 minutes during that time, while the amount of change from the start of the measurement to 45 minutes later was calculated as the charge accumulation amount. The minimum offset voltage value means a DC voltage value at which flicker is minimized by measuring a V-F curve (voltage-flicker curve) when an AC voltage having a relative transmittance of 23% is applied. The reason for using the AC voltage at which the relative transmittance is 23% is that this AC voltage value corresponds to a region where the change in luminance with respect to voltage is large, and therefore it is convenient for evaluating the accumulated charge through the luminance.

Since the accumulated charge affects the display as a disorder of liquid crystal alignment or an afterimage, and remarkably reduces the display quality of the liquid crystal element, it can be said that the smaller the amount of charge accumulated during driving, the better. Specifically, the case where the charge accumulation amount was less than 100 mV was evaluated as “○”, and the case where it was 100 mV or more was evaluated as “x”.

[Relief properties of accumulated charge]

With respect to the FFS driving liquid crystal cell fabricated above, the LED backlight is provided from below the two polarizing plates in a state where it is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the pixel electrode and the counter electrode are short-circuited to bring them to the same potential. It irradiated and adjusted the angle of the liquid crystal cell so that the brightness|luminance of the LED backlight transmitted light measured from the top of 2 polarizing plates might become the minimum. This evaluation was performed on the temperature condition of the state whose temperature of a liquid crystal cell is 23 degreeC. The liquid crystal cell evaluated the liquid crystal cell, after applying the alternating voltage of 20 mV at the frequency of 1 kHz for 30 minutes in order to exclude the influence by charging.

Next, the V-T curve (voltage-transmittance curve) was measured, applying the alternating voltage of frequency 30Hz to this liquid crystal cell, and the relative transmittance|permeability computed the alternating voltage value used as 23 % as a drive voltage. Since this AC voltage value corresponds to a region where the change in luminance with respect to voltage is large, it is convenient for evaluating the accumulated charge through the luminance.

And after applying the alternating current voltage of frequency 30Hz from which a relative transmittance|permeability will be 23 % for 5 minutes, the DC voltage of +1.0V was superimposed, and it was made to drive for 30 minutes. Then, the DC voltage was cut off, and only the AC voltage with a frequency of 30 Hz from which a relative transmittance|permeability becomes 23 % was applied again for 30 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 is 23% from the state where the relative transmittance immediately after superimposing the DC voltage is 30% or more. The time required for deterioration was evaluated. It can be said that the relaxation characteristic of the accumulation|storage charge is favorable, so that this time is short. Specifically, the time for which the relative transmittance fell to 30% or less was quantified from the time when the application of the DC voltage was started until 30 minutes passed. When the relative transmittance fell to 30% or less in less than 20 minutes, it was evaluated as "○", and when it became 20 minutes or more, it evaluated as "x".

[Afterimage characteristics due to long-term AC drive]

About the FFS drive liquid crystal cell produced above, the alternating voltage of +/-5V was applied at 60 Hz in a 60 degreeC constant temperature environment for 120 hours. Then, it was set as the state made short between the pixel electrode of a liquid crystal cell, and a counter electrode, and it was left to stand at room temperature as it is for one day.

About the liquid crystal cell which performed the said process, the shift|offset|difference of the orientation direction of the liquid crystal of the 1st area|region of a pixel, and the orientation direction of the liquid crystal of a 2nd area|region in the voltage unapplied state was computed as an angle.

Specifically, the liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, the backlight is turned on, and the arrangement angle of the liquid crystal cell is adjusted so that the intensity of transmitted light in the first region of the pixel is the smallest, and then The rotation angle required when the liquid crystal cell was rotated so that the transmitted light intensity of the 2nd area|region of a pixel might become the smallest was calculated|required.

It can be said that the afterimage characteristic by long-term alternating current drive is so favorable that the value of this rotation angle is small. Specifically, when the rotation angle was less than 0.5 degrees, it was evaluated as "○", and when it became 0.5 degrees or more, it evaluated as "x".

[Voltage retention rate]

With respect to the FFS drive liquid crystal cell produced above, after applying a voltage of 1 V to the liquid crystal display element for voltage retention evaluation at an application time of 60 microseconds and an interval of 1667 milliseconds, voltage retention 1667 milliseconds after application release (%) was measured at 60 degreeC. Specifically, when the voltage retention ratio was 95% or more, it was evaluated as "○", and when it was less than 95%, it was evaluated as "x".

<Evaluation result>

The evaluation result of the liquid crystal cell using each liquid crystal aligning agent of the said Example and a comparative example is shown in following Table 2.

It turns out that the liquid crystal display element using the liquid crystal aligning agent of this invention has a small amount of electric charge accumulation, and the relaxation characteristic of an accumulation|storage electric charge is favorable.

In addition, all content of the specification of JP Patent application 2018-229216 for which it applied on December 6, 2018, a claim, drawing, and abstract is referred here, and it takes in as an indication of the specification of this invention.

Claims (11)

The liquid crystal aligning agent containing a following polymer (A) and a polymer (B).
Polymer (A): A polymer obtained by reaction of a tetracarboxylic-acid derivative component, and the diamine component containing the diamine shown in following formula (1), and the diamine shown in following formula (2).

Polymer (B): A polymer obtained by reaction of a tetracarboxylic-acid derivative component and the diamine component containing at least 1 sort(s) of the diamine represented by following formula (3).

(Y ₂ is a divalent organic group having a nitrogen atom or nitrogen-containing aromatic heterocyclic ring bonded to an aromatic) The method of claim 1,
The liquid crystal aligning agent in which the said polymer (A) and/or the diamine component in a polymer (B) contains at least 1 sort(s) of the diamine shown by following formula (4) further.

(Y ₁ is represents a divalent organic group. R 2 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.) 3. The method of claim 2,
The liquid crystal aligning agent in which the diamine component in the said polymer (A) contains the diamine which is _{a divalent organic group in which Y<1>} in Formula (4) has a structure of following formula (5).

(D represents a protecting group which is detached by heating and replaced with a hydrogen atom, and * represents a connection point with another structure.) 4. The method according to any one of claims 1 to 3,
The diamine residue derived from the diamine of Formula (1) in the said polymer (A) is 10 mol% or more of all the diamine residues which a polymer (A) has, The diamine residue derived from the diamine of Formula (2) is, The liquid crystal aligning agent which is 30 mol% or more of all the diamine residues which a polymer (A) has. 5. The method according to any one of claims 1 to 4,
The liquid crystal aligning agent whose content of a polymer (A) is 10-50 mass % with respect to the total amount of the said polymer (A) and a polymer (B), and content of a polymer (B) is 90-50 mass %. 6. The method according to any one of claims 1 to 5,
The liquid crystal aligning agent for liquid crystal display elements of a transverse electric field drive system. 7. The method according to any one of claims 1 to 6,
The liquid crystal aligning agent whose transverse electric field drive method is an FFS drive method. The liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of Claims 1-7. The liquid crystal display element which has the liquid crystal aligning film of Claim 8. 10. The method of claim 9,
A liquid crystal display device that is a transverse electric field driving method. 10. The method of claim 9,
A liquid crystal display element that is an FFS drive system.