CN111868617A

CN111868617A - Liquid crystal aligning agent, polymer for obtaining the same, liquid crystal alignment film, and liquid crystal display element using the same

Info

Publication number: CN111868617A
Application number: CN201980019440.2A
Authority: CN
Inventors: 野田尚宏
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2018-03-23
Filing date: 2019-03-20
Publication date: 2020-10-30
Anticipated expiration: 2039-03-20
Also published as: TW201940538A; KR20200130427A; JP7510119B2; JPWO2019182070A1; WO2019182070A1; CN111868617B; TWI822744B; JP7239900B2; JP2023052560A

Abstract

A liquid crystal aligning agent contains a polymer which is polyurea or a polyurea copolymer having a structure represented by the following formula (1).

Wherein X represents a divalent organic group derived from a diisocyanate derivative, and Y represents a divalent organic group derived from a diamine derivative. R₁Represents an alkyl group having 1 to 4 carbon atoms, and R₁Is a straight chain alkyl or branched alkyl. R₂Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms or represented by the following formula (1-1)An organic group. Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

Wherein the black dots represent bonding sites with nitrogen atoms, R₁Ra and Rb with the above R₁Ra and Rb have the same meaning.

Description

Liquid crystal aligning agent, polymer for obtaining the same, liquid crystal alignment film, and liquid crystal display element using the same

Technical Field

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

Background

In a liquid crystal display element, a liquid crystal alignment film plays a role of aligning liquid crystal in a certain direction. A major liquid crystal alignment film that is currently used in industry is formed by applying a polyimide-based liquid crystal alignment agent composed of a polyamic acid (also referred to as a polyimide precursor or a polyamic acid) and a polyimide solution to a substrate and baking the applied liquid crystal alignment agent. In the case of orienting the liquid crystal in parallel or obliquely with respect to the substrate surface, a surface stretching treatment (rubbing treatment) using rubbing may be performed after film formation. As a method for replacing the rubbing treatment, a method using an anisotropic photochemical reaction by irradiation with polarized ultraviolet rays or the like has also been proposed.

In order to improve the display characteristics of liquid crystal display elements, various techniques have been proposed. For example, patent document 1 (jp-a-2-287324) proposes the use of a polyimide resin having a specific repeating structure in order to obtain a high Voltage Holding Ratio (VHR). In addition, patent document 2 (jp-a-10-104633) proposes the use of a soluble polyimide having a nitrogen atom in addition to an imide group in order to shorten the time required to remove a residual image.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2-287324

Patent document 2: japanese laid-open patent publication No. 10-104633

Disclosure of Invention

(problems to be solved by the invention)

In recent years, along with the multifunctionalization and diversification of liquid crystal displays (LCD panels), developments have been made from displays using glass substrates to flexible displays using resin substrates (plastic substrates, i.e., film substrates). Therefore, a liquid crystal alignment film that can be obtained by firing at a low temperature is required, and in addition, reliability (high voltage holding ratio and the like) required for the liquid crystal alignment film is also required.

Examples of the material used for the liquid crystal alignment film include polyimide precursors such as polyamic acids and polyamic acid esters, and polyimides obtained by dehydrating these by firing or chemical reaction. Among them, polyamic acid is easy to synthesize and has excellent solubility in a solvent, and thus a liquid crystal aligning agent having excellent coatability and film-forming properties on a substrate can be obtained. However, since polyamic acid is easily decomposed by hydrolysis or the like in its structure, it is difficult to secure reliability for a long period of time in a liquid crystal alignment film obtained using the polyamic acid.

On the other hand, since a soluble polyimide (a solvent-soluble polyimide obtained by a dehydration reaction of a polyamic acid) is preimidated, a thermosetting step of heating to imidize it is not necessary, and therefore, firing at a relatively low temperature is possible. Further, since the liquid crystal alignment film obtained using a soluble polyimide has excellent chemical stability and heat resistance, it is easy to ensure reliability for a long period of time. However, since the selection of a solvent capable of dissolving the soluble polyimide is small, the usable solvent is limited, and as a result, when the soluble polyimide is used, a defect is easily generated in a coating film due to precipitation during coating or film formation. In recent years, along with the increase in size and definition of LCD panels and diversification of use environments, a search for a method for solving various problems and improving various characteristics has been sought.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal aligning agent which can be fired at a low temperature and has good printability (solubility of the obtained polymer in an organic solvent). Also disclosed is a polymer which enables to obtain the above-mentioned liquid crystal aligning agent. In addition, when rubbing treatment is performed, a liquid crystal alignment film having excellent rubbing resistance, good liquid crystal alignment properties (that is, a low pretilt angle can be achieved), and a high voltage holding ratio is provided. Further, a liquid crystal display element having the liquid crystal alignment film is provided.

(means for solving the problems)

The present inventors have conducted extensive studies and, as a result, have found that a polymer having a specific structure and a liquid crystal aligning agent using the same are effective for achieving the above objects, thereby completing the present invention. The polymer is novel, and the monomer used for obtaining the polymer also includes a novel compound.

That is, the gist of the present invention is the following 1 to 9.

1. A liquid crystal aligning agent contains a polymer which is polyurea or a polyurea copolymer having a structure represented by the following formula (1).

[ solution 1]

Wherein X represents a divalent organic group derived from a diisocyanate derivative, and Y represents a divalent organic group derived from a diamine derivative. R₁Represents an alkyl group having 1 to 4 carbon atoms, R₁Is a straight chain alkyl or branched alkyl. R₂Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an organic group represented by the following formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

[ solution 2]

Wherein the black dots represent bonding sites with nitrogen atoms, R₁Ra and Rb with R as described above₁Ra and Rb have the same meaning.

2. The liquid crystal aligning agent according to claim 1, wherein the liquid crystal aligning agent contains a polymer, and the polymer is polyurea or a polyurea copolymer obtained from a diamine derivative represented by the following formula (2) and a diisocyanate derivative.

[ solution 3]

Wherein A represents a divalent organic group of an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C each independently represents a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. R₁、R₂Ra and Rb with R as described above₁、R₂Ra and Rb have the same meaning.

3. The liquid crystal aligning agent according to claim 2, wherein the liquid crystal aligning agent contains a polymer, and the polymer is polyurea or a polyurea copolymer obtained from a diamino compound represented by the following formula (3) among the diamine derivatives and a diisocyanate derivative.

[ solution 4]

Wherein Ar represents an aryl group, and D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R₁、R₂Ra and Rb with R as described above₁、R₂Ra and Rb have the same meaning.

4. The liquid crystal aligning agent according to claim 3, wherein the liquid crystal aligning agent contains a polymer, and the polymer is polyurea or a polyurea copolymer obtained from a diamino compound represented by the following formula (3-a) in the diamine derivative and a diisocyanate derivative.

[ solution 5]

In the formula, D and R₁With D and R as described above₁Have the same meaning.

5. A polymer obtained from a diamino compound represented by the following formula (3-1) and a diisocyanate derivative.

[ solution 6]

In the formula, R₁Represents an alkyl group having 1 to 4 carbon atoms, R ₁Is a straight chain alkyl or branched alkyl. B represents a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

6. The polymer according to claim 5, which is obtained from the diamino compound and at least 1 of diisocyanate derivatives represented by the following formulas (4-1) to (4-11) and (4-13).

[ solution 7]

7. A liquid crystal aligning agent comprising the polymer according to claim 5 or 6.

8. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 4 and 7.

9. A liquid crystal display element using the liquid crystal alignment film of 8.

(effect of the invention)

According to the present invention, a liquid crystal aligning agent which can be fired at a low temperature, can provide a high-quality liquid crystal alignment film, and has excellent printability can be provided. Further, according to the present invention, a novel polymer for obtaining the above-mentioned liquid crystal aligning agent can be provided. Further, according to the present invention, there can be provided a liquid crystal alignment film which is excellent in rubbing resistance when subjected to rubbing treatment, can realize a low pretilt angle, and is also high in voltage holding ratio. Further, according to the present invention, a liquid crystal display element using the above liquid crystal alignment film can be provided.

Detailed Description

The liquid crystal aligning agent according to one embodiment of the present invention contains a polymer according to one embodiment of the present invention, which is obtained from a diamine derivative represented by formula (2) (hereinafter, sometimes referred to as "diamine") and a diisocyanate derivative (hereinafter, sometimes referred to as "diisocyanate").

< diamine used in the present invention >

The diamine used in the present invention is represented by formula (2).

[ solution 8]

Wherein A represents a divalent organic group of a propionic acid aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C each independently represents a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. R₁Represents an alkyl group having 1 to 4 carbon atoms, R₁Is a straight chain alkyl or branched alkyl. R₂Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an organic group represented by the formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

In the formula (2), a is preferably an aromatic hydrocarbon group, B is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and C is preferably a single bond, from the viewpoint of obtaining a liquid crystal alignment film excellent in polymerization reactivity, heat resistance, and liquid crystal alignment properties of the monomer. The following structures are specifically exemplified in the formula (2).

[ solution 9]

Wherein Ar represents an aryl group, and D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R ₁、R₂Ra and Rb with R as described above₁、R₂Ra and Rb have the same meaning.

In the formula (3), Ar is preferably a phenyl group, and R is preferably a phenyl group, from the viewpoints that a reagent for synthesizing a diamine is easily available, the reactivity with a diisocyanate is good, the physical properties of the obtained polymer are good, and the like₂Preferably a hydrogen atom. Accordingly, the formula (3) is preferably a structure represented by the following formula (3-a)'. Among them, in the formula (3), Ra and Rb are each preferably a hydrogen atom. Therefore, the formula (3) is particularly preferably represented by the formula (3-a).

[ solution 10]

From the viewpoint that the target monomer can be obtained appropriately and all of the above properties are easily improved, the above formula (3-a)' is preferably represented by the following formula (3-1).

[ solution 11]

In the formula, B, R₁Ra and Rb are the same as B, R1, Ra and Rb described above. In the formula (3-1), when B represents carbon atoms 1 and 2 and Ra and Rb each represent a hydrogen atom, the formula (3-1) is represented by the formula (3-1a) and the formula (3-1B).

[ solution 12]

In the formula, R₁And R as defined above₁Have the same meaning.

Specific examples of the diamine represented by the formula (2) are not limited to the diamine represented by the formula (3). In the synthesis of the polymer, a part of the diamine represented by the formula (2) or (3) may be replaced with a diamine represented by the formula (5) described later, as long as the effect of the present invention is not impaired (for example, a low pretilt angle can be achieved).

< diisocyanate used in the present invention >

The diisocyanate used in the present invention is represented by formula (4).

[ solution 13]

OCN-X-NCO (4)

Wherein X represents a divalent organic group. The formula (4) is preferably represented by the formulae (4-1) to (4-11) and (4-13).

[ solution 14]

When the aliphatic diisocyanates represented by the formulae (4-1) to (4-5) are used, the resulting polymers are more soluble in the solvent than when the aromatic diisocyanates represented by the formulae (4-6) to (4-13) are used. On the other hand, the aromatic diisocyanate reacts well with diamine compared to the aliphatic diisocyanate. For example, the aromatic diisocyanate represented by the formula (4-6) or the formula (4-7) and the diamine react well, and the heat resistance of the liquid crystal alignment film obtained can be improved.

The formula (4) is preferably a formula (4-1), a formula (4-7), a formula (4-8), a formula (4-9) or a formula (4-10) from the viewpoint of obtaining a compound having high versatility when the polymer is obtained, and from the viewpoint of improving the characteristics of the polymer obtained. In addition, from the viewpoint of the liquid crystal alignment property of the obtained liquid crystal alignment film being good, formula (4) is preferably formula (4-13).

However, the formula (4) is not limited to the above as long as it is within the scope of the present invention. The diisocyanate which is easily available can be suitably used depending on the aimed properties of the obtained polymer, liquid crystal aligning agent, liquid crystal alignment film and the like. 2 or more diisocyanates can be used in combination.

< diamine >

In order to obtain the above-mentioned polymer, a part of the diamine represented by the formula (2) may be replaced with a diamine other than the diamine (other diamine). In general, since there are many kinds of diamines and many compounds having organic groups which exert various functions, the use of another diamine may impart a further effect to the polymer or may further enhance the effect of the diamine. The ratio of the number of moles of the other diamine to the number of moles of the diamine represented by the formula (2) is arbitrary within a range not impairing the effects of the present invention (for example, a low pretilt angle can be achieved). For example, the ratio may be 0.5 or less. Of course, other diamines may not be used. Examples of such other diamines include diamines represented by the following formula (5).

[ solution 15]

Wherein Y represents a divalent organic group. Examples of the structure of Y include, but are not limited to, the following formulae (Y-1) to (Y-49) and the formulae (Y-57) to (Y-175). R₅Each independently represents a hydrogen atom, a methyl group or an ethyl group. A polyamic acid is provided in the reaction of a tetracarboxylic dianhydride and a diamine, and a polyurea is provided in the reaction of a diisocyanate and a diamine.

[ solution 16]

[ solution 17]

[ solution 18]

[ solution 19]

[ solution 20]

[ solution 21]

[ solution 22]

[ solution 23]

In the formula, n is an integer of 1 to 6 unless otherwise specified.

< Polymer >

The polymer is polyurea and polyurea copolymer means that the polymer is polyurea and/or polyurea copolymer. The above polymer is represented by formula (1).

[ solution 24]

Wherein X represents a divalent organic group derived from diisocyanate, and Y represents a divalent organic group derived from diamine. R₁Represents an alkyl group having 1 to 4 carbon atoms, R₁Is a straight chain alkyl or branched alkyl. R₂Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an organic group represented by the following formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

[ solution 25]

Polyurea is strongly bonded to hydrogen bonds due to the polarity of the urea bond site, and therefore the obtained film has excellent mechanical strength. On the other hand, the strong hydrogen bonding force may cause aggregation of the polymer, and may deteriorate stability of the polymer solution (e.g., increase in viscosity of the polymer solution, precipitation of a part of the polymer, gelation of the polymer solution, etc.). Therefore, depending on the structure of the polyurea, usable solvents are limited, and for example, it is necessary to use a solvent having high polarity and high boiling point.

The polymer has a structure represented by formula (1), that is, a structure in which an organic group represented by formula (1-1) is substituted on the N atom of polyurea. The organic group represented by formula (1-1) inhibits the formation of hydrogen bonds, whereby the polymers can be prevented from coagulating with each other. Therefore, the stability of the polymer solution is greatly improved. Therefore, when a polymer solution of polyurea is obtained, the selection range of usable solvents can be widened, and even firing at a low temperature can be performed, so that the printability can be greatly improved. The urea bond site may form hydantoin rings or intermolecular crosslinks depending on the firing temperature during film formation.

< reaction solution >

The reaction solution (organic solvent used in the reaction for obtaining the polymer) is not particularly limited as long as the polymer is dissolved in the reaction solution. Specific examples thereof include N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, γ -butyrolactone, isopropanol, methoxymethylpentanol, dipentene, ethylpentyl ketone, methylnonyl ketone, methylethyl ketone, methylisoamyl ketone, methylisopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, Dipropylene glycol monomethyl ether, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, vinyl carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, propylene glycol, Methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, and the like. These may be used alone, or 2 or more of them may be used in combination. The reaction solution may be mixed with the polymer in a range where the polymer is not precipitated, even a solution in which the polymer is not dissolved.

In addition, the water content in the reaction solution may be a cause of inhibiting the polymerization reaction and hydrolyzing the polymer formed, and therefore, it is preferable to use a dehydrated and dried reaction solution. When reacting diisocyanate and diamine in a reaction solution, there may be mentioned a method of adding diisocyanate directly by stirring the reaction solution in which diamine is dispersed or dissolved, or a method of adding diisocyanate by dispersing or dissolving diisocyanate in a reaction solution; on the contrary, a method of adding a diamine to a reaction solution in which a diisocyanate is dispersed or dissolved; a method of alternately adding diisocyanate and diamine to the reaction solution, and the like, and any of these methods can be used.

When the diisocyanate or diamine is composed of a plurality of compounds, the reaction may be carried out in a state of being mixed in advance, or the reaction may be carried out individually and sequentially, or the low molecular weight materials after the respective reactions may be mixed to produce a high molecular weight material. The polymerization temperature in this case may be any temperature from-20 ℃ to 150 ℃, and preferably from-5 ℃ to 100 ℃. The reaction can be carried out at an arbitrary concentration, but if the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and if the concentration is too high, the viscosity of the reaction solution becomes too high, and uniform stirring is difficult, and therefore, the total concentration of the diisocyanate and the diamine in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction is carried out at a high concentration in the initial stage of the reaction, and thereafter, the reaction solution may be added.

In the polymerization reaction of polyurea, the ratio of the total mole number of diisocyanate to the total mole number of diamine is preferably 0.8 to 1.2. As in the case of the usual polycondensation reaction, the closer the molar ratio is to 1.0, the larger the molecular weight of the polymer to be produced.

[ recovery of Polymer ]

When the polymer produced is recovered from the reaction solution, the reaction solution may be introduced into a poor solvent to precipitate the polymer. Examples of the poor solvent include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and water. The polymer precipitated by the introduction of the poor solvent may be recovered by filtration, and then dried at normal temperature or under reduced pressure or by heating. Further, if the recovered polymer is redissolved in an organic solvent and the operation of reprecipitation and recovery is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons and the like, and if 3 or more kinds of poor solvents selected from them are used, the purification efficiency is further improved, which is preferable.

The molecular weight of the polymer is preferably 5000 to 1000000, more preferably 10000 to 150000, in terms of a weight average molecular weight measured by a gpc (gel coating chromatography) method, in consideration of the strength of a coating film obtained from the polymer, the ease of work in forming the coating film, the uniformity of the film thickness of the coating film, and the like.

< liquid Crystal Aligning agent >

A liquid crystal aligning agent according to one embodiment of the present invention is a coating liquid for forming a liquid crystal alignment film, and a resin component for forming a coating film (resin coating film) is dissolved in an organic solvent. The resin component comprises at least one of the above polymers. The content of the resin component in the liquid crystal aligning agent is preferably 2 to 20 mass%, more preferably 3 to 15 mass%, and particularly preferably 3 to 10 mass%. In the present invention, the polymer contained in the resin component may be all the above-mentioned polymers, and other polymers (other polymers) may be contained within the scope of the gist of the present invention. The content of the other polymer in the resin component is 0.5 to 15% by mass, preferably 1 to 10% by mass. Examples of the other polymers include acrylic polymers, methacrylic polymers, novolak resins, polyhydroxystyrene, polyimide precursors, polyimides, polyamides, polyesters, cellulose and polysiloxanes.

The organic solvent used in the liquid crystal aligning agent is not particularly limited as long as it is an organic solvent that dissolves the resin component. Specific examples thereof include N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylsulfoxide, γ -butyrolactone, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, 1, 3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, vinyl carbonate, methyl ethyl ketone, methyl ethyl methyl isobutyl ketone, methyl isopropyl ketone, methyl ethyl propyl ketone, methyl ethyl ketone, methyl, Propylene carbonate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, and the like. These may be used alone, or 2 or more of them may be used in combination.

The liquid crystal aligning agent may contain components other than those described above. Examples thereof include a solvent and a compound for improving the uniformity of film thickness and the smoothness of the surface of a coating film formed by applying a liquid crystal alignment agent, and a compound for improving the adhesion between a liquid crystal alignment film and a substrate.

Examples of the solvent (poor solvent) for improving the uniformity of the film thickness and the smoothness of the surface include solvents having a low surface tension, for example, isopropyl alcohol, methoxymethylpentanol, methylcellosolve, ethylcellosolve, butylcellosolve, methylcellosolve acetate, ethylcellosolve acetate, butylcarbitol, ethylcarbitol acetate, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-t-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, dipropylene glycol monopropyl ether, ethylene glycol monoacetate, ethylene glycol monoacetyl ether, ethylene glycol, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl 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 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, ethyl acetate, n-butyl acetate, ethyl propionate, n-butyl acetate, ethyl pyruvate, methyl 3-methoxypropionate, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and the like. These poor solvents may be used in 1 kind, or may be used in combination of two or more kinds. When the poor solvent is used, the content of the organic solvent in the liquid crystal aligning agent is preferably 5 to 80% by mass, more preferably 20 to 60% by mass, based on the total amount of the organic solvent.

Examples of the compound for improving the uniformity of the film thickness and the smoothness of the surface of the coating film include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surfactant. More specifically, for example, EFTOP EF301, EF303, EF352 (manufactured by Tohkem Products), MEGAFAC F171, F173, R-30 (manufactured by Dainippon ink Co., Ltd.), Fluorad FC430, FC431 (manufactured by Sumitomo 3M Co., Ltd.), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi glass Co., Ltd.) and the like can be given. The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

Specific examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy-containing compound shown below. Examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, N-aminopropyltriethoxysilane, N-aminopropyltrimethoxysilane, N-aminopropyltriethoxysilane, N-ureidopropyltrimethoxysilane, N-ethyltrimethoxysilane, 10-trimethoxysilyl-1, 4, 7-triazodecane, 10-triethoxysilyl-1, 4, 7-triazodecane, 9-trimethoxysilyl-3, 6-diaza-nonyl acetate, 9-triethoxysilyl-3, 6-diaza-nonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyl-triethoxysilane, N-trimethoxy-methyl-ethyl-3-methyl-ethyl-1, 4, 7-triethoxysilyl-1, 4, 7-triethoxy, Ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2, 4-hexanediol, N, N, N ', N ', -tetraglycidyl-m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N ', -tetraglycidyl-4, 4 ' -diaminodiphenylmethane, and the like.

In addition, in order to improve adhesion between the substrate and the film and to prevent a decrease in electrical characteristics due to light irradiation from a backlight, the following phenol plastic-based additive may be added. Specific examples of the phenolic plastic additive are shown below, but the additive is not limited to this structure.

[ solution 26]

When a compound that improves the adhesion between the substrate and the film is used, the amount of the compound used is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the resin component contained in the liquid crystal aligning agent. If the amount is less than the above value, the adhesion is difficult to improve, and if the amount is more than the above value, the liquid crystal alignment properties may be deteriorated.

In the liquid crystal aligning agent, a dielectric material or a conductive material may be added for the purpose of changing electrical characteristics such as dielectric constant and conductivity of the liquid crystal alignment film, and a specific crosslinkable compound may be added for the purpose of improving hardness and density of the film when the liquid crystal alignment film is formed, unless the effects of the present invention are impaired.

< liquid crystal alignment film & liquid crystal display element >

The liquid crystal alignment agent is applied to a substrate and fired, and then subjected to alignment treatment such as rubbing or light irradiation, thereby obtaining a liquid crystal alignment film according to one embodiment of the present invention. As the substrate, a glass substrate or a plastic substrate (for example, an acrylic substrate or a polycarbonate substrate) having high transparency can be used. In addition, from the viewpoint of simplifying the process of manufacturing the liquid crystal display element, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed. In the reflective liquid crystal display element, an opaque material such as a silicon wafer may be used for one substrate, and in this case, a material that reflects light such as aluminum may be used for an electrode. The method for applying the liquid crystal aligning agent is not particularly limited, and industrially, spin coating printing, screen printing, offset printing, flexo printing, inkjet printing, and the like are generally used. Other coating methods include dipping, roll coater, slit coater, spin coater, and the like, and these methods can be used according to the purpose.

Firing may be carried out by a heating unit such as a hot plate at 50 to 300 ℃, preferably 80 to 250 ℃. By evaporating the organic solvent in the liquid crystal aligning agent, a coating film can be formed. If the thickness of the coating film is too large, the power consumption of the liquid crystal display element tends to increase, and if it is too small, the reliability of the liquid crystal display element may be lowered, and therefore, it is preferably 5nm to 300nm, more preferably 10nm to 150 nm. When the liquid crystal is aligned horizontally or obliquely, the fired coating film is subjected to alignment treatment by rubbing, polarized ultraviolet irradiation, or the like.

In the above method, a substrate with a liquid crystal alignment film is obtained from the liquid crystal alignment agent, and then a liquid crystal cell is produced by a known method, whereby a liquid crystal display element according to one embodiment of the present invention can be obtained. As an example of a method for manufacturing a liquid crystal cell, there is a method in which 1 pair of substrates on which liquid crystal alignment films are formed are prepared, spacers are scattered on the liquid crystal alignment film of one substrate, the other substrate is bonded so that the liquid crystal alignment film surface is on the inside, and liquid crystal is injected under reduced pressure to seal the substrates. Alternatively, a method of dropping liquid crystal on a liquid crystal alignment film surface on which spacers are dispersed, and then attaching substrates and sealing the same may be mentioned. The thickness of the spacer in this case is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. The liquid crystal display element produced using the liquid crystal aligning agent is excellent in reliability, and therefore, can be suitably used for a large-screen, high-definition liquid crystal television or the like.

Examples

< Synthesis of diamine >

Example 1

Synthesis of (4-aminobenzyl) glycine ethyl ester [ NG4ABA ]

[ solution 27]

First step of

105.6g (0.694mol) of glycine ethyl ester hydrochloride, THF500g, and Tris were added to a 1L four-necked flask equipped with a nitrogen inlet tube and a reflux tube 93.6g (0.925mol) of ethylamine was stirred at room temperature for 1 hour with a mechanical stirrer, and then heated at the reflux temperature of THF (70 ℃ C.) to dissolve 50.0g (0.231mol) of 4-nitrobenzyl bromide in 500.0g of THF, and the solution was slowly added dropwise, followed by further reaction for 24 hours after completion of the dropwise addition. The reaction was terminated when 4-nitrobenzyl bromide disappeared, the precipitated solid was removed by filtration, THF was removed by a rotary evaporator, and the obtained crude product was redissolved in 300.0g of ethyl acetate. This solution was washed 3 times with 100g of pure water, 300g of a 10% hydrochloric acid aqueous solution was added thereto, and the mixture was stirred for 1 hour to recover the water layer side, and the water layer was washed 3 times with 100g of ethyl acetate. To the aqueous layer was further added 300g of ethyl acetate, and potassium carbonate was slowly added to the mixture to stir the mixture at about pH 10 for 1 hour, and the organic phase side was recovered and washed 3 times with 100g of pure water. The organic phase was dried by adding anhydrous magnesium sulfate, filtered, added with activated carbon, stirred for a while, then, the activated carbon was removed by filtration, and the solvent was removed by a rotary evaporator to obtain 46.0g (0.193mol) of a pale yellow viscous substance as a target substance (nitre base). By using¹H-NMR confirmed that the objective compound was obtained.

¹HNMR(500MHz、CDCl₃)：8.2(2H)、7.53(2H)、4.22(2H)、3.93(2H)、3.42(2H)、1.89(1H)、1.27(3H)

Second step of

To a 500ml four-necked flask equipped with a nitrogen inlet tube and a stirrer, 45.0g (0.19mol) of the nitro compound obtained above, 300.0g of THF, and 4.5g of iron-doped platinum carbon were added, and the inside of the flask was carefully replaced with a hydrogen atmosphere to carry out a reaction at room temperature for 24 hours. The reaction was terminated when the starting materials disappeared, platinum carbon was removed by a membrane filter, activated carbon (manufactured by aigret) was added to the filtrate, and the mixture was stirred at 40 ℃ for 30 minutes. Then, the mixture was filtered again, and after removing the solvent by a rotary evaporator, the filtrate was dried by a high vacuum pump to obtain 35.4g (0.17 mol: yield 89%) of a pale yellow viscous substance as a target substance. By using ¹H-NMR confirmed the target product (NP4 ABA).

¹HNMR(500MHz、CDCl₃)：6.99(2H)、6.63(2H)、4.15(2H)、3.70(2H)、3.38(2H)、3.00(2H)、1.24(3H)

Example 2

Synthesis of (3-aminobenzyl) glycine ethyl ester [ NG3ABA ]

[ solution 28]

The starting material, 4-nitrobenzyl bromide, in example 1 was changed to 3-nitrobenzyl bromide. The target (NG3ABA) was obtained as a pale yellow solid with a yield of 37.4g (0.18 mol: 94%). By passing¹H-NMR confirmed that the objective compound was obtained.

¹HNMR(500MHz、CDCl₃)：7.10(1H)、6.65(1H)、6.57(1H)、4.16(2H)、3.70(2H)、3.39(2H)、3.09(2H)、1.25(3H)

Example 3

Synthesis of (4-aminophenylethyl) glycine ethyl ester [ NG4APhA ]

[ solution 29]

First step of

In a 1L four-necked flask equipped with a nitrogen introduction tube and a reflux tube, 50g (0.246mol) of 4-nitrophenylethylamine hydrochloride, 500g of THF, and 62.1g (0.604mol) of triethylamine were added, and the mixture was stirred at room temperature for 1 hour using a mechanical stirrer, and heated at a temperature at which THF was refluxed (70 ℃ C.) to dissolve 25.1g (0.205mol) of ethyl 2-chloroacetate in 300g of THF, and the solution was slowly added dropwise, and after the dropwise addition, the reaction was further carried out for 24 hours. The reaction was terminated when ethyl 2-chloroacetate disappeared (confirmed by HPLC), the precipitated solid was removed by filtration, THF was removed by a rotary evaporator, and the obtained crude product was redissolved with 500g of ethyl acetate. This solution was washed 3 times with 100g of pure water, 500g of a 10% hydrochloric acid aqueous solution was added thereto, and the mixture was stirred for 1 hour to recover the water layer side, and the water layer was washed 3 times with 100g of ethyl acetate. To the aqueous layer was further added 500g of ethyl acetate, and potassium carbonate was gradually added to adjust the pH to about 10, followed by stirring for 1 hour, to recover the organic phase, and the mixture was washed 3 times with 100g of pure water. Adding anhydrous magnesium sulfate to the organic phase, drying, filtering, and adding activated carbon After stirring for a while, the activated carbon was removed by filtration, and the solvent was removed by a rotary evaporator to obtain 34.2g (0.136 mol: yield 66%) of a pale yellow viscous substance as a target substance. By passing¹H-NMR confirmed that the target compound (nitroxide) was obtained.

¹HNMR(500MHz、CDCl₃)：8.14(2H)、7.37(2H)、4.16(2H)、3.43(2H)、2.95(4H)、2.19(1H)、1.25(3H)

Second step of

30.0g of the nitro compound, THF300g, and 3.0g of iron-doped platinum carbon obtained above were added to a 500ml four-necked flask equipped with a nitrogen introduction tube and a stirrer, and the inside of the vessel was carefully replaced with a hydrogen atmosphere to carry out a reaction at room temperature for 24 hours. The reaction was terminated when the starting materials disappeared, platinum carbon was removed by a membrane filter, activated carbon (manufactured by aigret) was added to the filtrate, and the mixture was stirred at 40 ℃ for 30 minutes. Then, the mixture was filtered again, and after removing the solvent by a rotary evaporator, the filtrate was dried by a high vacuum pump to obtain 25.1g (0.113 mol: yield 95%) of a pale yellow viscous product (NG4 APhA). By passing¹H-NMR confirmed that the objective compound was obtained.

¹HNMR(500MHz、CDCl₃)：6.99(2H)、6.60(2H)、4.18(2H)、3.42(2H)、2.89(2H)、2.86(2H)、2.75(2H)、1.24(3H)

< abbreviation >

Abbreviations used in the preparation of the liquid crystal aligning agents are as follows.

(diisocyanate)

IDI: isophorone diisocyanate

4 IBI: (isocyanatomethyl) phenyl-isocyanates

DI-3 MG: 1, 3-bis (4-isocyanatophenoxy) propane

DI-2 MG: 1, 2-bis (4-isocyanatophenoxy) ethane

[ solution 30]

(diamine)

NG4 ABA: (4-aminobenzyl) glycine ethyl ester

NG3 ABA: (3-aminobenzyl) glycine ethyl ester

NG4 APhA: (4-Aminophenylethyl) glycine ethyl ester

Me3 ABA: n-methyl-3-aminobenzylamine

Me4 APhA: n-methyl-4-aminophenylethylamine

DA-3 MG: 1, 3-bis (4-aminophenoxy) propane

[ solution 31]

(solvent)

NMP: n-methyl-2-pyrrolidone

BCS: butyl cellosolve

GBL: gamma-butyrolactone

The conditions for measuring the molecular weight of the polyimide are as follows.

The device comprises the following steps: normal temperature Gel Permeation Chromatography (GPC) device (SSC-7200) manufactured by SENSHU scientific Inc

Column: column manufactured by Shodex (KD-803, KD-805)

Column temperature: 50 deg.C

Eluent: n, N' -dimethylformamide (as additive, lithium bromide-hydrate (LiBr. H)₂O) 30mmol/L, phosphoric acid-anhydrous crystals (O-phosphoric acid) 30mmol/L, THF 10ml/L)

Flow rate: 1.0 ml/min

Calibration curve preparation standard sample: TSK Standard polyethylene oxide (molecular weight of 9000000, 150000, 100000, 30000) manufactured by Tosoh corporation and polyethylene glycol (molecular weight of 12000, 4000, 1000) manufactured by Polymer laboratories Inc

< Synthesis of Polymer >

Example 4

DI-2MG/NG3ABA

In a 50ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer, NG3ABA1.00g (4.80mmol) was weighed, NMP13.43g was added and dissolved, DI-2MG 1.37g (4.60mmol) was added, and the reaction was carried out at 40 ℃ for 24 hours under a nitrogen atmosphere. Thus, a polymer (polymer solution: P-1) having a concentration of 15 mass% and a viscosity of 420mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 46200.

Example 5

DI-2MG/NG4ABA

In a 50ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer, 1.00g (4.80mmol) of NG4ABA was weighed, 13.32g of NMP was added and dissolved, 1.35g (4.56mmol) of DI-2MG was added, and the reaction was carried out at 40 ℃ for 24 hours under a nitrogen atmosphere. Thus, a polymer (polymer solution: P-2) having a concentration of 15 mass% and a viscosity of 370mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 39800.

example 6

DI-3MG/NG4APhA

In a 50ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer, 1.00g (4.50mmol) of NG4APhA was weighed out, 13.20g of NMP was added and dissolved, 1.33g (4.28mmol) of DI-3MG was added, and the reaction was carried out at 40 ℃ for 24 hours under a nitrogen atmosphere. Thus, a polymer (polymer solution: P-3) having a concentration of 15 mass% and a viscosity of 440mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 46300.

example 7

4IBI/NG4APhA、DA-3MG

In a 50ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer, 0.50g (2.25mmol) of NG4APhA and 0.58g (2.25mmol) of DA-3MG were weighed, 10.48g of NMP was added and dissolved, 0.77g (4.41mmol) of 4IBI was added, and the reaction was carried out at 40 ℃ for 24 hours under a nitrogen atmosphere. Thus, a polymer (polymer solution: P-4) having a concentration of 15 mass% and a viscosity of 280mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 37300.

Example 8

IDI、DI-3MG/NG4ABA、DA-3MG

A50 ml 2-necked flask equipped with a nitrogen inlet tube and a stirrer was charged with NG4ABA 0.50g (2.40mmol) and DA-3MG0.62g (2.40mmol), dissolved by adding NMP 13.60g, added with DI-3MG 0.74g (2.40mmol) and IDI 0.54g (2.42mmol), and reacted at 40 ℃ for 24 hours under nitrogen atmosphere. Thus, a polymer (polymer solution: P-5) having a concentration of 15 mass% and a viscosity of 330mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 41600.

comparative example 1

DI-2MG/Me3ABA

A50 ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer was charged with 1.00g (7.34mmol) of Me3ABA, dissolved by adding 19.36g of NMP, and reacted at 40 ℃ for 24 hours under a nitrogen atmosphere with 2.24g (7.57mmol) of DI-2 MG. Thus, a polymer (polymer solution: PRef-1) having a concentration of 15 mass% and a viscosity of 530mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 39900.

comparative example 2

DI-2MG/Me4APhA

In a 50ml 2-neck flask equipped with a nitrogen introduction tube and a stirrer, 1.00g (6.66mmol) of Me4APhA was weighed, 16.38g of NMP was added and dissolved, 1.89g (6.39mmol) of DI-2MG was added, and the reaction was carried out at 40 ℃ for 24 hours under a nitrogen atmosphere. Thus, a polymer (polymer solution: PRef-2) having a concentration of 15 mass% and a viscosity of 490mPas was obtained. The weight average molecular weight of the resulting polymer Mw: 41300.

< adjustment of liquid Crystal alignment agent >

Example 9

10.0g of the polymer (P-1) obtained in example 4 was weighed into a 50ml Erlenmeyer flask equipped with a stirrer, NMP2.5g, GBL 5.0g, and BCS 7.5g were added, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-1) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass%, and BCS30 mass%.

Example 10

10.0g of the polymer (P-2) obtained in example 5 was weighed into a 50-ml Erlenmeyer flask equipped with a stirrer, 2.5g of NMP, 5.0g of GBL and 7.5g of BCS were added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-2) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass% and BCS30 mass%.

Example 11

10.0g of the polymer (P-3) obtained in example 6 was weighed in a 50ml Erlenmeyer flask equipped with a stirrer, and 2.5g of NMP, 5.0g of GBL and 7.5g of BCS were added thereto and stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-3) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass% and BCS30 mass%.

Example 12

10.0g of the polymer (P-4) obtained in example 7 was weighed into a 50-ml Erlenmeyer flask equipped with a stirrer, 2.5g of NMP, 5.0g of GBL and 7.5g of BCS were added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-4) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass% and BCS30 mass%.

Example 13

10.0g of the polymer (P-5) obtained in example 8 was weighed into a 50-ml Erlenmeyer flask equipped with a stirrer, 2.5g of NMP, 5.0g of GBL and 7.5g of BCS were added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-5) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass% and BCS30 mass%.

Comparative example 3

10.0g of the polymer (PRef-1) obtained in comparative example 1 was weighed in a 50ml Erlenmeyer flask equipped with a stirrer, 2.5g of NMP, 5.0g of GBL, and 7.5g of BCS were added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-6) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass%, and BCS30 mass%.

Comparative example 4

10.0g of the polymer (PRef-2) obtained in comparative example 2 was weighed into a 50ml Erlenmeyer flask equipped with a stirrer, 2.5g of NMP, 5.0g of GBL and 7.5g of BCS were added thereto, and the mixture was stirred at room temperature for 30 minutes to obtain a liquid crystal aligning agent (AL-7) having a solid content of 6.0 mass%, NMP44 mass%, GBL20 mass% and BCS30 mass%.

Comparative example 5

SE-6414, manufactured by Nissan chemical Co., Ltd., was used as a liquid crystal aligning agent (AL-8).

Liquid crystal alignment films were evaluated by the following methods using the liquid crystal alignment agents (AL-1 to AL-5) of examples 9 to 13 and the liquid crystal alignment agents (AL-6 to AL-8) of comparative examples 3 to 5.

< evaluation of whitening resistance and coatability (printability) >

1 drop of the obtained liquid crystal aligning agent was dropped onto each of the well-cleaned Cr substrates, and the substrates were left at room temperature of 25 ℃ and humidity of 60%, and the time until whitening (whitening) was measured. Whitening resistance was evaluated based on the measured time.

After the liquid crystal aligning agent was filtered with a 1.0 μm filter, a coatability test was performed by flexography on a cleaned Cr plate using an alignment film printer ("angiomer" manufactured by japan photographic printing company).

About 1.0ml of a liquid crystal aligning agent was dropped on the anilox roller, and after 10 times of idling, the printing machine was stopped for 10 minutes to dry the printing plate. Then, 1 Cr substrate was printed, and the printed substrate was left on a hot plate at 70 ℃ for 5 minutes to temporarily dry the coating film, and the film state was observed. The film thickness unevenness and the film thickness unevenness at the edge portion were mainly observed by visual observation and 50-fold magnification by an optical microscope ("ECLIPSEME 600" manufactured by nikon corporation).

< evaluation of liquid Crystal alignment, Voltage holding ratio and Pre-Tilt Angle >

[ Observation of liquid Crystal alignment and production of liquid Crystal cell ]

The liquid crystal aligning agent was filtered with a 1.0 μm filter, and applied to a substrate with electrodes (a glass substrate having a size of 30mm in width by 40mm in length and a thickness of 1.1mm, an electrode was an ITO electrode having a rectangular shape of 10mm in width by 40mm in length and a thickness of 35 nm) by spin coating printing. After drying on a hot plate at 50 ℃ for 5 minutes, the film was baked in an IR type oven at 180 ℃ for 20 minutes to form a coating film having a film thickness of 100 nm. The film was rubbed with rayon cloth (YA-20R manufactured by Giken chemical Co., Ltd.) to give a substrate with a liquid crystal alignment film (roll diameter: 120mm, roll rotation speed: 1000rpm, moving speed: 20mm/sec, press-in length: 0.4mm), then washed by irradiating with ultrasonic waves in pure water for 1 minute, and after removing water droplets by air blowing, dried at 80 ℃ for 15 minutes.

2 pieces of the above-described substrates with liquid crystal alignment films were prepared, spacers of 4 μm were spread on the surfaces of the 1 pieces of liquid crystal alignment films, a sealant was printed thereon, and the other 1 piece of substrates were bonded so that the rubbing direction was opposite and the film surfaces were opposite to each other, and then the sealant was cured to prepare empty cells. MLC-2041 (manufactured by merck) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. Then, the liquid crystal orientation was observed, and the liquid crystal cell was heated at 110 ℃ for 1 hour and left at 23 ℃ overnight to obtain a liquid crystal cell for measuring voltage holding ratio.

The liquid crystal cell for measuring voltage holding ratio obtained by the above procedure was used, and a voltage of 1V was applied at a temperature of 60 ℃ for 60 μ s, and the voltage after 166.7ms was measured to calculate how much the voltage can be held as the voltage holding ratio. The voltage holding ratio was measured using a VHR-1 voltage holding ratio measuring apparatus manufactured by Tokyo Seiko Seikagaku-Sho Ltd.

[ evaluation of pretilt Angle ]

The pretilt angle was measured using an Axo Scan muller matrix polarimeter manufactured by Optometric corporation.

[ evaluation of Friction resistance ]

The liquid crystal aligning agent was filtered with a 1.0 μm filter, and applied to a substrate with electrodes (a glass substrate having a size of 30mm in width by 40mm in length and a thickness of 1.1mm, an electrode was an ITO electrode having a rectangular shape of 10mm in width by 40mm in length and a thickness of 35 nm) by spin coating printing. After drying on a hot plate at 50 ℃ for 5 minutes, the film was baked in an IR type oven at 180 ℃ for 20 minutes to form a coating film having a film thickness of 100 nm. The film was rubbed with rayon cloth (YA-20R manufactured by Giken chemical Co., Ltd.) (roll diameter: 120mm, roll rotation speed: 1000rpm, moving speed: 20mm/sec, press-in length: 0.4mm), and then the rubbing resistance was evaluated by using a confocal laser microscope. The case of film peeling was evaluated as x, the case of film with a large number of scratches (cut れカス) and scratches observed was evaluated as Δ, and the case of good film (the case of film peeling was not observed and film with no large number of scratches and scratches observed) was evaluated as o. The results of the various evaluations are shown in table 1.

[ Table 1]

The liquid crystal aligning agents of examples 9 to 13 were significantly superior in whitening resistance and also had good printability as compared with comparative examples. Comparative example 5 is a polyamic acid material, and therefore, is a material having excellent whitening resistance and printability. It is expected that the whitening resistance and the printability of examples 9 to 13 are equal to or higher than those of comparative example 5. It is considered that the organic group represented by the formula (1-1) is consumed in intramolecular reaction, intermolecular crosslinking, and the like, and therefore, examples 9 to 13 are very excellent in abrasion resistance as compared with comparative examples 3 and 4. It is considered that comparative example 5 was inferior in the rubbing resistance because the imidization reaction was not carried out.

In addition, in the liquid crystal cells obtained by using the liquid crystal aligning agents of examples 9 to 13, a low pretilt angle and a high voltage holding ratio can be obtained. This is considered to be because the organic group represented by the formula (1-1) does not cause decomposition reaction as in the case of polyamic acid when used in various reactions. Therefore, the liquid crystal alignment film according to one embodiment of the present invention is considered to be very promising as a liquid crystal alignment film that can be obtained by firing at a low temperature. A liquid crystal alignment film and a liquid crystal display element can be suitably obtained by using any of the liquid crystal aligning agents of examples 7 to 10.

Industrial applicability

The liquid crystal display element produced by using the liquid crystal aligning agent of the present invention can be used as a highly reliable liquid crystal display device, and can be suitably used for various display elements such as an IPS liquid crystal display element and an FFS liquid crystal display element.

Claims

1. A liquid crystal aligning agent characterized by containing a polymer which is a polyurea and a polyurea copolymer having a structure represented by the following formula (1),

wherein X represents a divalent organic group derived from a diisocyanate derivative, Y represents a divalent organic group derived from a diamine derivative, and R₁Represents an alkyl group having 1 to 4 carbon atoms, and R₁Is a straight-chain alkyl or branched-chain alkyl radical, R₂Represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an organic group represented by the following formula (1-1), Ra and Rb each independently represent a hydrogen atom or a 1 to c carbon atom2 of an aliphatic hydrocarbon group having a hydroxyl group,

2. The liquid crystal aligning agent according to claim 1, wherein the liquid crystal aligning agent contains a polymer which is polyurea and polyurea copolymer obtained from a diamine derivative represented by the following formula (2) and a diisocyanate derivative,

Wherein A represents a divalent organic group of an aliphatic hydrocarbon group or an aromatic hydrocarbon group, B and C each independently represents a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and R₁、R₂Ra and Rb with R as described above₁、R₂Ra and Rb have the same meaning.

3. The liquid crystal aligning agent according to claim 2, wherein the liquid crystal aligning agent contains a polymer which is polyurea and polyurea copolymer obtained from a diamino compound represented by the following formula (3) and a diisocyanate derivative among the diamine derivatives,

wherein Ar represents an aryl group, D represents a single bond or a C1-5 hydrocarbon group, and R represents₁、R₂Ra and Rb with R as described above₁、R₂Ra and Rb have the same meaning.

4. The liquid crystal aligning agent according to claim 3, wherein the liquid crystal aligning agent contains a polymer which is polyurea and polyurea copolymer obtained from a diamino compound represented by the following formula (3-a) among the diamine derivatives and a diisocyanate derivative,

5. A polymer characterized by being obtained from a diamino compound represented by the following formula (3-1) and a diisocyanate derivative,

in the formula, R₁Represents an alkyl group having 1 to 4 carbon atoms, and R ₁Is a straight-chain alkyl group or a branched-chain alkyl group, B represents a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

6. The polymer according to claim 5, wherein the polymer is obtained from the diamino compound and at least 1 of diisocyanate derivatives represented by the following formulas (4-1) to (4-11) and (4-13),

7. a liquid crystal aligning agent, wherein the polymer according to claim 5 or 6 is used.

9. A liquid crystal display element, wherein the liquid crystal alignment film according to claim 8 is used.