WO2019182071A1 - Liquid crystal alignment agent, polymer for obtaining same, liquid crystal alignment film, and liquid crystal display element using same - Google Patents

Abstract

Provided is a liquid crystal alignment agent that uses a polymer obtained from the following: a diamine derivative represented by formula (1); a diisocyanate derivative; and a monomer selected from among diamines and diisocyanates and having a specific side chain. In the formula, A represents a divalent organic group selected from among aliphatic hydrocarbon groups and aromatic hydrocarbon groups and B and C each independently represent a single bond or an aliphatic hydrocarbon group having 1-5 carbon atoms. R₁ represents an alkyl group that has 1-4 carbon atoms and that may be branched. R₂ represents a hydrogen atom, an aliphatic hydrocarbon group having 1-4 carbon atoms, or an organic group represented by formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 or 2 carbon atoms.

Description

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

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

In a liquid crystal display element, a liquid crystal alignment film plays a role of aligning liquid crystals in a certain direction. Currently, the main liquid crystal alignment film used industrially is a polyimide liquid crystal aligning agent made of polyamic acid (also called polyimide precursor or polyamic acid) or a polyimide solution applied to a substrate and baked. A film is formed.

A number of techniques have been proposed to improve the display characteristics of liquid crystal display elements. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2-287324) proposes to use a polyimide resin having a specific repeating structure in order to obtain a high voltage holding ratio (VHR). Patent Document 2 (Japanese Patent Laid-Open No. 10-104633) proposes the use of a soluble polyimide having a nitrogen atom in addition to the imide group in order to shorten the time until the afterimage is erased.

JP-A-2-287324 JP-A-10-104633

In recent years, with the increase in functionality and diversification of liquid crystal displays (LCD panels), development is progressing from displays using glass substrates to flexible displays using resin substrates (plastic substrates, ie film substrates). . Accordingly, a liquid crystal alignment film that can be obtained by baking at a low temperature has become necessary, and in addition, the reliability required for the liquid crystal alignment film (high voltage holding ratio, etc.) has been required. Yes.

Examples of the material used for the liquid crystal alignment film include polyimide precursors such as polyamide acid and polyamide acid ester, and polyimide obtained by dehydrating them by baking or chemical reaction. Among these, since the polyamic acid is easy to synthesize and has excellent solubility in a solvent, it is possible to obtain a liquid crystal aligning agent having excellent coating properties and film forming properties on a substrate. However, since polyamic acid is easily decomposed by hydrolysis or the like due to its structure, it is difficult to ensure reliability over a long period of time with a liquid crystal alignment film obtained using the polyamic acid.

On the other hand, soluble polyimide (polyimide that is soluble in a solvent obtained by polyamic acid dehydration reaction) is pre-midified, so there is no need for a heat-curing step to imidize by heating, and therefore firing at a relatively low temperature. Is possible. Moreover, since it is excellent in chemical stability and heat resistance, in the liquid crystal aligning film obtained using soluble polyimide, it becomes easy to ensure reliability over a long period of time. However, soluble polyimide has few choices of solvent that can be dissolved, and therefore, the solvent that can be used is limited. As a result, when soluble polyimide is used, precipitation or the like occurs during coating and film formation. It is easy to be defective. In recent years, with the increase in size, definition, and usage environment of LCD panels, there has been a demand for searching for methods that can solve various problems and improve various characteristics.

The present invention has been made in view of the above circumstances, and the problem is that the liquid crystal alignment is capable of firing at a low temperature and has good printability (the solubility of the resulting polymer in an organic solvent). It is to provide an agent. Moreover, it is providing the polymer which can obtain the said liquid crystal aligning agent. Another object of the present invention is to provide a liquid crystal alignment film having good liquid crystal alignment (that is, a high pretilt angle can be realized) and a high voltage holding ratio. Furthermore, it is providing the liquid crystal display element which has the said liquid crystal aligning film.

As a result of diligent research, the present inventors have found that a polymer having a specific structure and a liquid crystal aligning agent using the polymer are effective for achieving the above object, and have completed the present invention. It was. In addition, the said polymer is novel and the monomer for obtaining the said polymer also contains the novel compound.

That is, the present invention provides the following 1. ~ 10. Is the gist.
1. A liquid crystal aligning agent using a polymer obtained from a diamine derivative represented by the following formula (1), a diisocyanate derivative, and a monomer selected from diamine or diisocyanate having a specific side chain.

In the formula, A represents a divalent organic group selected from an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C each independently represent a single bond or an aliphatic carbon group having 1 to 5 carbon atoms. Indicates a hydrogen group.
R ₁ represents an alkyl group having 1 to 4 carbon atoms and may be branched. R ₂ represents 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.

2. The monomer containing the specific side chain is represented by the following formula (2): Liquid crystal aligning agent as described in.

In the formula, N represents an amino group or an isocyanate group, R ₃ represents a single bond or a divalent organic group, and X ¹ , X ² , and X ³ each independently represent a benzene ring or a cyclohexane ring. , P, q and r each independently represents an integer of 0 or 1, and R ₄ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a divalent having 12 to 25 carbon atoms having a steroid skeleton. An organic group is shown.

3. The diamine derivative is a diamino compound represented by the following formula (3). Liquid crystal aligning agent as described in.

In the formula, Ar represents an aryl group, and D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R ₁ , R ₂ , Ra and Rb are synonymous with the above R ₁ , R ₂ , Ra and Rb.

4. 2. The diamine derivative is a diamino compound represented by the following formula (3-a): Liquid crystal aligning agent as described in.

Wherein, D and _{R 1} have the same meanings as D and _{R 1} above.

5. A polymer obtained from a diamino compound represented by the following formula (3-1), a diisocyanate derivative, and a monomer selected from diamine or diisocyanate having a specific side chain.

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms and may be branched. 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. 4. The monomer containing the specific side chain is represented by the following formula (2). The polymer described in 1.

In the formula, N represents an amino group or an isocyanate group, R ₃ represents a single bond or a divalent organic group, and X ¹ , X ² , and X ³ each independently represent a benzene ring or a cyclohexane ring. , P, q and r each independently represents an integer of 0 or 1, and R ₄ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a divalent having 12 to 25 carbon atoms having a steroid skeleton. An organic group is shown.

7. 5. the diisocyanate derivative is at least one of structures represented by the following formulas (4-1) to (4-13); The polymer described in 1.

In the formula, R ₅ and R ₆ each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.

8. 5. ~ 7. Liquid crystal aligning agent using the polymer as described in any one of these.

9. 1. ~ 4. And 8. Liquid crystal aligning film obtained from the liquid crystal aligning agent as described in any one of these.

10. 9. A liquid crystal display element using the liquid crystal alignment film described in 1.

According to the present invention, it is possible to provide a liquid crystal aligning agent that can be fired at a low temperature and can obtain a high-quality liquid crystal aligning film and has excellent printability. Moreover, according to this invention, the novel polymer for obtaining the said liquid crystal aligning agent can be provided. In addition, according to the present invention, in addition to realizing a high pretilt angle, a liquid crystal alignment film having a high voltage holding ratio can be provided. Furthermore, according to this invention, the liquid crystal display element using the said liquid crystal aligning film can be provided.

The liquid crystal aligning agent which is one embodiment of the present invention includes a diamine derivative represented by formula (1) (hereinafter sometimes referred to as “diamine”), a diisocyanate derivative (hereinafter sometimes referred to as “diisocyanate”), It contains a polymer according to one embodiment of the present invention, which is obtained from a monomer selected from diamine or diisocyanate having a specific side chain (hereinafter sometimes referred to as “side chain-containing monomer”).

<Diamine used in the present invention>
The diamine used in the present invention is represented by the formula (1).

In the formula, A represents a divalent organic group of an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C each independently represent a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. Indicates. R1 represents an alkyl group having 1 to 4 carbon atoms and may be branched. R2 represents 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.

From the standpoint of obtaining a liquid crystal alignment film excellent in polymerization reactivity of monomers, heat resistance and liquid crystal alignment properties, in formula (1), A is an aromatic hydrocarbon group, and B is 1 carbon atom. It is preferable that the aliphatic hydrocarbon group of 1 to 3 and C is a single bond. Specific examples of the formula (1) include the following structures.

In the formula, Ar represents an aryl group, and D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R ₁ , R ₂ , Ra and Rb are synonymous with the above R ₁ , R ₂ , Ra and Rb.

When considering the viewpoint that it is easy to obtain a reagent for synthesizing diamine, the reactivity with diisocyanate is good, the physical properties of the obtained polymer are good, etc., formula (3) Among them, Ar is preferably a phenyl group, and R ₂ is preferably a hydrogen atom. Therefore, the formula (3) is preferably a structure represented by the following formula (3-a) ′. Especially, in Formula (3), it is preferable that Ra and Rb are each a hydrogen atom. Therefore, the formula (3) is particularly preferably represented by the formula (3-a).

Wherein, D and _{R 1} have the same meanings as D and _{R 1} above.

From the standpoint that the desired monomer can be suitably obtained and all of the above characteristics are likely to be favorable, the above formula (3-a) ′ is preferably represented by the following formula (3-1). Is done.

In the formula, B, R ₁ , Ra and Rb have the same meanings as B, R ₁ , Ra and Rb. In Formula (3-1), when B has 1 and 2 carbon atoms, and Ra and Rb are each a hydrogen atom, Formula (3-1) can be represented by Formula (3-1a) and Formula (3-1b) It is represented by

Wherein, _{R 1} has the same meaning as _{R 1} described above.

However, a specific example of the diamine represented by the formula (1) is not limited to the diamine represented by the formula (3). If the effect of the present invention (for example, that a high pretilt angle can be realized) is not impaired, a part of the diamine represented by the formula (1) or the formula (3) may be used in synthesizing the polymer. You may substitute with the diamine represented by Formula (5) mentioned later.

<Diisocyanate used in the present invention>
The diisocyanate used in the present invention is represented by the following formula (4).

In the formula, X represents a divalent organic group. Formula (4) is preferably represented by Formula (4-1) to Formula (4-13).

In the formula, R ₅ and R ₆ each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.

When using aliphatic diisocyanates represented by formulas (4-1) to (4-5), compared to using aromatic diisocyanates represented by formulas (4-6) to (4-13) The resulting polymer is well dissolved in the solvent. On the other hand, the aromatic diisocyanate reacts better with diamine than the aliphatic diisocyanate. For example, aromatic diisocyanates such as those represented by formulas (4-6) and (4-7) can react well with diamines and improve the heat resistance of the resulting liquid crystal alignment film.

From the viewpoints of being a highly versatile compound for obtaining the polymer and improving the properties of the obtained polymer, the formula (4) is represented by the formula (4-1), the formula (4- 7), Formula (4-8), Formula (4-9), or Formula (4-10) is preferable. Further, the formula (5) is preferably the formula (4-12) from the viewpoint of improving the electrical characteristics of the obtained liquid crystal alignment film, and from the viewpoint of improving the liquid crystal alignment of the obtained liquid crystal alignment film. Is preferably formula (4-13).

However, formula (4) is not limited to the above as long as it is within the scope of the present invention. A readily available diisocyanate can be suitably used in accordance with target properties such as the obtained polymer, liquid crystal aligning agent, and liquid crystal aligning film. Two or more diisocyanates may be used in combination.

<Side chain-containing monomer used in the present invention>
The side chain-containing monomer used in the present invention is represented by the formula (2).

In the formula, N represents an amino group or an isocyanate group, R ₃ represents a single bond or a divalent organic group, and X ¹ , X ² , and X ³ each independently represent a benzene ring or a cyclohexane ring. , P, q and r each independently represents an integer of 0 or 1, R ₄ is selected from a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a carbon atom having 12 to 25 carbon atoms having a steroid skeleton. A valent organic group.

The side chain-containing monomer represented by the formula (2) contributes to increasing the pretilt angle of the liquid crystal. When the side chain-containing monomer is a diamine, the diamine may have a long-chain alkyl group, a perfluoroalkyl group, an aromatic cyclic group, an aliphatic cyclic group, a substituent combining these, a steroid skeleton group, and the like. preferable. Since the preferred size of the pretilt angle varies depending on the display mode of the liquid crystal display, the desired pretilt angle can be obtained by variously selecting the structure and amount of the side chain-containing monomer.

In the TN mode, which requires a pretilt angle of 3 ° to 5 °, which is lower than the VA mode, which will be described later, and the OCB mode, which requires a pretilt of 8 ° to 20 °, etc., there is a function to increase the pretilt angle (tilt development ability). It is preferable to use a relatively small side chain-containing monomer. As the side chain-containing monomer having a relatively small tilting ability, for example, in formula (2), R ₃ is preferably —O— or —NHCO— (or —CONH—), p is 0 to 1, and q is 0 to 1, r is preferably 0, and when p and / or q is 1, R ₄ is preferably a linear alkyl group having 1 to 12 carbon atoms, and when p = q = r = 0, R ₄ is carbon A divalent organic group which is a linear alkyl group of several tens to 22 or an organic group of 12 to 25 carbon atoms having a steroid skeleton is preferable. The specific structure of the side chain-containing monomer having a small tilting ability is shown in Table 1, but the formula (2) is not limited to the structure of Table 1. In each of [2-16] to [2-30] in Table 1, “—NHCO—” in R ₁ can be read as “—CONH—”.

From the viewpoint of improving the electrical properties of the obtained liquid crystal alignment film, side chain-containing monomers having long alkyl side chains such as [2-1] to [2-3] in Table 1 are preferred. Further, from the viewpoint of improving the liquid crystal alignment property and the stability of the pretilt of the obtained liquid crystal alignment film, the side chain-containing monomers represented by [2-25] to [2-27] in Table 1 are used. preferable.

On the other hand, by using a side chain-containing monomer having a large tilting ability, the liquid crystal is easily aligned vertically. Accordingly, as the structure of the formula (2) in the VA mode, for example, R ₃ is preferably —O—, —COO—, or —CH ₂ O—, p is 0 to 1, q is 0 to 1, and r is 0 to 1 is preferable, and R ₄ preferably has 2 to 22 carbon atoms. When p = q = r = 0, R ₄ is preferably a linear alkyl group having 18 to 22 carbon atoms or a divalent organic group having a steroid skeleton and having 12 to 25 carbon atoms. Specific structures of the side chain-containing monomers having a large tilting ability are shown in Tables 2-1 and 2-2, but the formula (4) is not limited to the structures of Tables 2-1 and 2-2.

The side chain-containing monomers in Table 2-1 and Table 2-2 are preferable when used in the VA mode because of their high tilting ability. In particular, [2-43], [2-92] and the like have a large tilting ability and can easily align the liquid crystal vertically even with a relatively small amount of side chains. In particular, [2-52] and [2-101] have extremely large tilting ability and can align the liquid crystal vertically even with a very small amount of side chain. Accordingly, these side chain-containing monomers are preferable in terms of improving the printability of the liquid crystal aligning agent.

On the other hand, the side chain-containing monomer represented by the formula (2) is selected from diamine or diisocyanate. However, diisocyanates are derived by causing highly toxic phosgene or the like to act on diamines. Therefore, from the viewpoint of easily obtaining the side chain-containing monomer, it is easier to use diamine as the side chain-containing monomer. Therefore, N in the formula (2) is preferably an amino group.

Monomers overlapping in Table 1 and Tables 2-1 and 2-2 may be used for both TN mode and OCB mode, and VA mode. is there. In obtaining the polymer, the content of the side chain-containing monomer is arbitrary within the scope of the present invention. For example, the number of moles of the side chain-containing monomer can be 0.05 to 0.5 with respect to the total number of moles of the diamine represented by the formula (1) and the side chain-containing monomer.

<Diamine>
In obtaining the above polymer, a part of the diamine represented by the formula (1) is replaced with other diamines (other diamines, that is, the diamines represented by the formula (1), and the side chain. It may be replaced with a diamine that does not correspond to the contained monomer. In general, diamines are abundant in types, and since many compounds have organic groups having various functions, by using other diamines in combination, further effects can be imparted to the polymer, The effect of the diamine may be further improved. The ratio of the number of moles of the other diamine to the number of moles of the diamine represented by the formula (1) is arbitrary as long as the effects of the present invention (for example, a high pretilt angle can be realized) are not impaired. Of course, other diamines may not be used in combination. Examples of such other diamines include diamines represented by the following formula (5).

In the formula, Y represents a divalent organic group. Examples of specific structures of Y are listed as in the following formulas (Y-1) to (Y-147), but are not limited thereto. In the formulas (Y-1) to (Y-147), the black point means the bonding site to the nitrogen atom. R ₇ each independently represents a hydrogen atom, a methyl group, or an ethyl group. The reaction between tetracarboxylic dianhydride and diamine gives polyamic acid, and the reaction between diisocyanate and diamine gives polyurea.

In formulas (Y-108) to (Y-112), A ₁ represents an alkyl group or a fluorine-containing alkyl group having 2 to 24 carbon atoms.

In formulas (Y-113) to (Y-114), A ₂ represents —O—, —OCH ₂ —, —CH ₂ O—, —COOCH ₂ —, or —CH ₂ OCO—, and A ₃ represents An alkyl group, an alkoxy group, a fluorine-containing alkyl group or a fluorine-containing alkoxy group having 1 to 22 carbon atoms is shown.

In formula (Y-115) to formula (Y-117), A ₄ represents —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O— , —OCH ₂ — or —CH ₂ —, and A ₅ represents an alkyl group, alkoxy group, fluorine-containing alkyl group or fluorine-containing alkoxy group having 1 to 22 carbon atoms.

In formula (Y-118) to formula (Y-119), A ₆ represents —COO—, —OCO—, —CONH—, —NHCO—, —COOCH ₂ —, —CH ₂ OCO—, —CH ₂ O— , —OCH ₂ —, —CH ₂ —, —O—, or —NH—, and A ₇ represents a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group, Or a hydroxyl group is shown.

In formulas (Y-120) to (Y-121), A ₈ represents an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.

In formulas (Y-122) to (Y-123), A ₉ represents an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.

In Formula (Y-132) to Formula (Y-137), A ₁₂ represents —COO—, —OCO—, —CONH—, —NHCO—, —CH ₂ —, —O—, —CO—, or —NH. -And A ₁₃ represents an alkyl group or a fluorine-containing alkyl group having 1 to 22 carbon atoms.

In the formulas (Y-140), (Y-144), and (Y-145), n represents an integer of 1 to 10.

<Polymer>
The polymer (polyurea and polyurea copolymer) is represented by the formula (6).

In the formula, X represents a divalent organic group derived from diisocyanate, and Y represents a divalent organic group derived from diamine. R ₁ represents an alkyl group having 1 to 4 carbon atoms and may be branched. R ₂ represents 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.

Wherein black dots denotes a point of attachment to the nitrogen _atom, R 1, Ra and Rb are as defined above _R 1, Ra and Rb.

Since polyurea forms strong hydrogen bonds depending on the polarity of the urea bond site, the resulting film has excellent mechanical strength. On the other hand, the strong hydrogen bonding force causes aggregation of the polymer and may deteriorate the stability of the polymer solution (the viscosity of the polymer solution increases, a part of the polymer precipitates, or the polymer solution gels). ,etc). Therefore, the usable solvent is limited depending on the structure of polyurea, and for example, it is necessary to use a highly polar and high boiling point solvent.

The polymer has a structure represented by the formula (6), that is, a structure in which an organic group represented by the formula (1-1) is substituted on the N atom of polyurea. The organic group represented by the formula (1-1) inhibits the formation of hydrogen bonds, thereby preventing the polymers from aggregating. For this reason, the stability of the polymer solution is greatly improved. Accordingly, in obtaining a polymer solution of polyurea, the range of selection of usable solvents can be expanded, and as a result, baking at low temperature and great improvement in printability are possible. Note that the urea bond site may form a hydantoin ring or an intermolecular bridge 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 it is a solution in which the polymer is dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, Dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl Cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl Ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, Dipropylene glycol 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 Tate, 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, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, pyruvine Acid methyl, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3 Ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N, N-dimethylpropanamide, Examples include 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like. These may be used alone or in admixture of two or more. As long as the polymer does not precipitate, even a solution that does not dissolve the polymer can be used by mixing with the reaction solution.

In addition, since water in the reaction solution inhibits the polymerization reaction and further causes hydrolysis of the produced polymer, it is preferable to use a dehydrated and dried reaction solution. When reacting diisocyanate and diamine in the reaction solution, the reaction solution in which the diamine is dispersed or dissolved is stirred, and the diisocyanate is added as it is or dispersed or dissolved in the reaction solution. Conversely, the diisocyanate is dispersed. Or the method of adding diamine to the dissolved reaction solution, the method of adding diisocyanate and diamine to a reaction solution alternately, etc. are mentioned, Any of these methods may be used.

In addition, when the diisocyanate or diamine is composed of a plurality of types of compounds, they may be reacted in a premixed state, may be individually reacted sequentially, or may be further reacted by individually reacting low molecular weight substances. It may be a body. In this case, the polymerization temperature can be selected from -20 ° C. to 150 ° C., but it is preferably in the range of −5 ° C. to 100 ° C. The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high and uniform stirring is difficult. It becomes. Therefore, the total concentration in the reaction solution of diisocyanate (diisocyanate represented by formula (4)) and diamine (diisocyanate represented by formulas (1) and (5)) is preferably from 1% by mass. 50% by mass, more preferably 5% by mass to 30% by mass. The initial stage of the reaction can be performed at a high concentration, and then a reaction solution can be added.

In the polymerization reaction of polyurea, the ratio between the total number of moles of diisocyanate (diisocyanate represented by formula (4)) and the total number of moles of diamine (diamines represented by formula (1) and formula (5)) Is preferably 0.8 to 1.2. Similar to the normal polycondensation reaction, the closer the molar ratio is to 1.0, the higher the molecular weight of the polymer produced.

[Recovery of polymer]
In order to recover the produced polymer from the reaction solution, the reaction solution may be poured 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, water and the like. The polymer that has been precipitated in a poor solvent and collected can be collected by filtration, and then dried at normal temperature or under reduced pressure at room temperature or by heating. Further, when the recovered polymer is redissolved in an organic solvent, and reprecipitation and recollection are repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more poor solvents selected from these because purification efficiency is further improved.

The molecular weight of the polymer is GPC (Gel) in consideration of the strength of the coating film obtained from the polymer, the ease of work when forming the coating film, the uniformity of the coating film thickness, and the like. The weight average molecular weight measured by the Permeation Chromatography method is preferably 5,000 to 1,000,000, and more preferably 10,000 to 150,000.

<Liquid crystal aligning agent>
The liquid crystal aligning agent which is 1 aspect of this invention is a coating liquid for forming a liquid crystal aligning film, and the resin component for forming a coating film (resin film) is melt | dissolving in the organic solvent. The resin component contains at least one kind of the polymer. The content of the resin component in the liquid crystal aligning agent is preferably 2% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and particularly preferably 3% by mass to 10% by mass. In the present invention, all of the polymers contained in the resin component may be the above polymers (polyurea and polyurea copolymers), and other polymers (within the scope of the present invention) Other polymers) may be included. In the resin component, the content of the other polymer is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass. Examples of such other polymers include acrylic polymer, methacrylic polymer, novolac resin, polyhydroxystyrene, polyimide precursor, polyimide, polyamide, polyester, cellulose, polysiloxane and the like.

The organic solvent used for 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, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, Tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethyl Propanamide, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme 4-hydroxy-4-methyl-2-pentanone and the like. These may be used alone or in admixture of two or more.

The liquid crystal aligning agent may contain components other than those described above. For example, a coating film formed by applying a liquid crystal aligning agent improves the adhesion between the liquid crystal alignment film and the substrate, or a solvent or compound that improves the film thickness uniformity or surface smoothness. Compounds and the like.

Solvents that improve film thickness uniformity and surface smoothness (poor solvents) include low surface tension solvents such as isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, Ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene Glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol Diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol 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, 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, pyruvine Methyl acetate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3- Butyl methoxypropionate, 1-methoxy-2-propanol, 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, lactate methyl ester, lactate ethyl ester, lactate Examples thereof include n-propyl ester, lactic acid n-butyl ester, and lactate isoamyl ester. These poor solvents may be used alone or in combination. When the above poor solvent is used, it is preferably 5% by mass to 80% by mass, more preferably 20% by mass to 60% by mass, based on the entire organic solvent contained in the liquid crystal aligning agent.

Examples of the compound that improves the uniformity of the film thickness and the smoothness of the coating film surface include a fluorine-based surfactant, a silicone-based surfactant, and a nonionic surfactant. More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), Florard FC430, FC431 (manufactured by Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). The use ratio of these surfactants is preferably 0.01 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 1 part by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal aligning agent. It is.

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds and epoxy group-containing compounds. For example, 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-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, 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, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N Examples include ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

Furthermore, in addition to improving the adhesion between the substrate and the film, the following phenoplast type additives may be added for the purpose of preventing deterioration of electrical characteristics caused by light irradiation by the backlight. Specific phenoplast additives are shown below, but are not limited to this structure.

When using the compound which improves the adhesiveness of a board | substrate and a film | membrane, the usage-amount of the compound shall be 0.1 mass part to 30 mass parts with respect to 100 mass parts of the resin component contained in a liquid crystal aligning agent. Is more preferable, and it is 1 to 20 parts by mass. If the amount used is less than the above value, it is difficult to improve the adhesion, and if it is more than the above value, the liquid crystal orientation may be deteriorated.

In addition to the solvents and compounds as described above, the liquid crystal aligning agent includes dielectric materials for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal alignment film as long as the effects of the present invention are not impaired. A predetermined crosslinkable compound may be added for the purpose of increasing the hardness and density of the body, the conductive material, and the liquid crystal alignment film.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent is applied onto a substrate and baked, and then subjected to an alignment treatment if necessary, and a liquid crystal alignment film according to one embodiment of the present invention is obtained even without an alignment treatment in vertical alignment applications. be able to. As the substrate, a highly transparent glass substrate, a plastic substrate (for example, an acrylic substrate or a polycarbonate substrate), or the like can be used. In addition, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed from the viewpoint of simplifying the process for manufacturing the liquid crystal display element. In the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used on one side of the substrate, and a material that reflects light such as aluminum can be used for the electrode in this case. The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, spin coating printing, screen printing, offset printing, flexographic printing, inkjet printing, and the like are common. Other coating methods include dip, roll coater, slit coater, spinner and the like, and these methods may be used depending on the purpose.

Calcination can be performed at 50 ° C. to 300 ° C., preferably 80 ° C. to 250 ° C., by a heating means such as a hot plate. A coating film can be formed by evaporating the organic solvent in the liquid crystal aligning agent. If the thickness of the coating film is too thick, the power consumption of the liquid crystal display element tends to increase, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, the thickness is preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm. .

The liquid crystal display element which is one embodiment of the present invention can be obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent by the above-described method and then manufacturing a liquid crystal cell by a known method. As an example of a method for manufacturing a liquid crystal cell, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and spacers are dispersed on the liquid crystal alignment film of one substrate so that the liquid crystal alignment film surface is on the inside. Then, the other substrate is bonded, and the liquid crystal is injected under reduced pressure to be sealed. Alternatively, there may be mentioned a method in which after the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacers are dispersed, the substrates are bonded together for sealing. The thickness of the spacer at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. Since the liquid crystal display element manufactured using the liquid crystal aligning agent is excellent in reliability, it can be suitably used for a large-screen, high-definition liquid crystal television.

<Synthesis of diamine>
Example 1
Synthesis of ethyl (4-aminobenzoyl) glycinate [NG4ABA]

First Step 105.6 g (0.694 mol) of glycine ethyl hydrochloride, 300 g of THF, and 93.6 g (0.925 mol) of triethylamine are added to a 1 L four-necked flask equipped with a nitrogen introduction tube and a reflux tube, and a mechanical stirrer is used. After stirring at room temperature for 1 hour, the mixture was heated at a temperature at which THF was refluxed (setting 70 ° C.), 50.0 g (0.231 mol) of 4-nitrobenzyl bromide was dissolved in 500.0 g of THF, and this was slowly added dropwise. After completion of dropping, the reaction was further continued for 24 hours. The reaction was terminated when 4-nitrobenzyl bromide disappeared, the precipitated solid was removed by filtration, THF was removed with a rotary evaporator, and the resulting crude product was redissolved with 300.0 g of ethyl acetate. This solution was washed 3 times with 100 g of pure water, 300 g of 10% hydrochloric acid aqueous solution was added and stirred for 1 hour, the aqueous layer side was recovered, and the aqueous layer was washed 3 times with 100 g of ethyl acetate. To the aqueous layer, 300 g of ethyl acetate was further added, potassium carbonate was slowly added, the pH was adjusted to about 10 and the mixture was stirred for 1 hour, the organic phase side was recovered, and washed with 100 g of pure water three times. After adding anhydrous magnesium sulfate to this organic phase, drying, filtering, adding activated carbon and stirring for a while, the activated carbon was removed by filtration, the solvent was removed with a rotary evaporator, and the target product (nitro body), a light yellow 46.0 g (0.193 mol) of a viscous body was obtained. It was confirmed by ¹ H-NMR that the desired product was obtained.
¹ H NMR (500 MHz, CDCl ₃ ): δ 8.2 (2H), 7.53 (2H), 4.22 (2H), 3.93 (2H), 3.42 (2H), 1.89 ( 1H), 1.27 (3H)

Second Step To a 500 ml four-necked flask equipped with a nitrogen inlet tube and a stirrer, 45.0 g (0.19 mol) of the nitro body obtained above, 300.0 g of THF, and 4.5 g of iron-doped platinum carbon are added, The inside of the vessel was carefully replaced with a hydrogen atmosphere and reacted at room temperature for 24 hours. When the raw material disappeared, the reaction was completed, platinum carbon was removed with a membrane filter, activated carbon (manufactured by Shirasagi) was added to the filtrate, and the mixture was stirred at 40 ° C. for 30 minutes. Then, after filtering again and removing the solvent with a rotary evaporator, it was dried with a high vacuum pump to obtain 35.4 g (0.17 mol: yield 89%) of a light yellow viscous body as a target product. It was confirmed by ¹ H-NMR that the desired product (NG4ABA) was obtained.
¹ H NMR (500 MHz, CDCl ₃ ): δ 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 ethyl (4-aminophenethyl) glycinate [NG4APhA]

Step 1 To a 1 L four-necked flask equipped with a nitrogen introduction tube and a reflux tube was added 50 g (0.246 mol) of 4-nitrophenethylamine hydrochloride, 500 g of THF, and 62.1 g (0.604 mol) of triethylamine, and a mechanical stirrer was used. The mixture was stirred at room temperature for 1 hour and heated at a temperature at which THF was refluxed (setting 70 ° C.). 25.1 g (0.205 mol) of 2-chloroethyl acetate was dissolved in 300 g of THF, and this was slowly added dropwise. The mixture was further reacted for 24 hours. When the ethyl 2-chloroacetate disappears (confirmed by HPLC), the reaction is completed, the precipitated solid is removed by filtration, the THF is removed by a rotary evaporator, and the resulting crude product is reconstituted with 500 g of ethyl acetate. Dissolved. This solution was washed 3 times with 100 g of pure water, 500 g of 10% hydrochloric acid aqueous solution was added and stirred for 1 hour, the aqueous layer side was recovered, and the aqueous layer was washed 3 times with 100 g of ethyl acetate. To the aqueous layer was further added 500 g of ethyl acetate, potassium carbonate was slowly added, the pH was adjusted to about 10 and the mixture was stirred for 1 hour, the organic phase side was recovered, and washed with 100 g of pure water three times. The organic phase was dried by adding anhydrous magnesium sulfate, filtered, activated carbon was added, and the mixture was stirred for a while. Then, the activated carbon was removed by filtration, the solvent was removed by a rotary evaporator, and 34.2 g of a light yellow viscous body as a target product ( 0.136 mol: yield 66%) was obtained. It was confirmed by ¹ H-NMR that the desired product (nitro compound) was obtained.
¹ H NMR (500 MHz, CDCl ₃ ): δ 8.14 (2H), 7.37 (2H), 4.16 (2H), 3.43 (2H), 2.95 (4H), 2.19 ( 1H), 1.25 (3H)

Second Step 30.0 g of the nitro compound obtained above, 300 g of THF, and 3.0 g of iron-doped platinum carbon are added to a 500 ml four-necked flask equipped with a nitrogen inlet tube and a stirring bar, and the inside of the container is carefully placed under a hydrogen atmosphere. And allowed to react at room temperature for 24 hours. When the raw material disappeared, the reaction was completed, platinum carbon was removed with a membrane filter, activated carbon (manufactured by Shirasagi) was added to the filtrate, and the mixture was stirred at 40 ° C. for 30 minutes. Then, after filtering again and removing the solvent with a rotary evaporator, it was dried with a high vacuum pump to obtain 25.1 g (0.113 mol: yield 95%) of a pale yellow viscous body which was the target product (NG4APhA). It was confirmed by ¹ H-NMR that the desired product was obtained.
¹ H NMR (500 MHz, CDCl ₃ ): δ 6.99 (2H), 6.60 (2H), 4.18 (2H), 3.42 (2H), 2.89 (2H), 2.86 ( 2H), 2.75 (2H), 1.24 (3H)

<Abbreviations>
The abbreviations used in the preparation of the liquid crystal aligning agent are as follows.
(Diisocyanate)
IDI: Isophorone diisocyanate DI-2MG: 1,2-bis (4-isocyanatophenoxy) ethane

(Diamine)
p-PDA: paraphenylenediamine NG4ABA: ethyl (4-aminobenzyl) glycinate NG4APhA: ethyl (4-aminophenethyl) glycinate Me4APhA: N-methyl-4-aminophenethylamine DA-3MG: 1,3-di (4-amino) Phenoxy) propane APC16: 2-hexadecyloxy-1,3-diaminobenzene PCH7: 4- (4- (4-heptylcyclohexyl) phenoxy) benzene-1,3-diamine

(Tetracarboxylic dianhydride)
CBDA: cyclobutane tetracarboxylic dianhydride

(solvent)
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve GBL: γ-butyrolactone

Moreover, the molecular weight measurement conditions of polyimide are as follows.
Apparatus: Room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Co., Ltd.
Column: Column made by Shodex (KD-803, KD-805)
Column temperature: 50 ° C
Eluent: N, N′-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, THF is 10ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight of about 9,000,150,000, 100,000, 30,000) manufactured by Tosoh Corporation and polyethylene glycol (manufactured by Polymer Laboratories) (Molecular weight about 12,000, 4,000, 1,000)

<Synthesis of polymer>
Example 3
DI-2MG / NG4ABA, APC16
In a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirring bar, DI-2MG 2.00 g (6.75 mmol) was measured, 19.61 g of NMP was added and dissolved, and 0.24 g (0.68 mmol) of APC16 was added. Then, it was made to react at room temperature for 1 hour. Further, 1.22 g (5.88 mmol) of NG4ABA was added and reacted at 40 ° C. for 24 hours under a nitrogen atmosphere. As a result, a polymer (polymer solution: P-1) having a concentration of 15% by mass and a viscosity of 220 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 37200.

Example 4
DI-2MG / NG4APhA, APC16
DI-2MG 2.00 g (6.75 mmol) was measured in a 50 ml two-necked flask equipped with a nitrogen introduction tube and a stirring bar, NMP 20.12 g was added and dissolved, and APC16 0.24 g (0.68 mmol) was added. Then, it was made to react at room temperature for 1 hour. Further, 1.31 g (5.88 mmol) of NG4APhA was added and reacted at 40 ° C. for 24 hours in a nitrogen atmosphere. As a result, a polymer (polymer solution: P-2) having a concentration of 15% by mass and a viscosity of 280 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 39100.

Example 5
DI-2MG / NG4ABA, PCH7
In a 50 ml two-necked flask equipped with a nitrogen introduction tube and a stirring bar, 2.00 g (6.75 mmol) of DI-2MG was measured, and 20.57 g of NMP was added and dissolved, and 0.52 g (1.36 mmol) of PCH7 was added. Then, it was made to react at room temperature for 1 hour. Further, 1.11 g (5.34 mmol) of NG4ABA was added and reacted at 40 ° C. for 24 hours under a nitrogen atmosphere. As a result, a polymer (polymer solution: P-3) having a concentration of 15% by mass and a viscosity of 230 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 40200.

Example 6
IDI, DI-2MG / NG4ABA, PCH7
In a 50 ml two-necked flask equipped with a nitrogen introduction tube and a stirring bar, DI-2MG 1.00 g (3.38 mmol) and NMP 14.05 g were added and dissolved, and then PCH7 0.37 g (0.97 mmol) was added, followed by room temperature. For 1 hour. Further, 0.32 g (1.45 mmol) of IDI and 0.79 g (3.81 mmol) of NG4ABA were added and reacted at 40 ° C. for 24 hours in a nitrogen atmosphere. As a result, a polymer (polymer solution: P-4) having a concentration of 15% by mass and a viscosity of 300 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 44200.

Comparative Example 1
DI-2MG / Me4APhA, APC16
In a 50 ml two-necked flask equipped with a nitrogen introduction tube and a stirring bar, DI-2MG 2.00 g (6.75 mmol) was measured, NMP 17.73 g was added and dissolved, and APC16 0.24 g (0.68 mmol) was added. Then, it was made to react at room temperature for 1 hour. Further, Me9APhA (0.89 g, 5.94 mmol) was added and reacted at 40 ° C. for 24 hours under a nitrogen atmosphere. As a result, a polymer (polymer solution: PRef-1) having a concentration of 15% by mass and a viscosity of 320 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 39900.

Comparative Example 2
DI-2MG / Me4APhA, PCH7
In a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirring bar, 2.00 g (6.75 mmol) of DI-2MG was measured, 18.7 g of NMP was added and dissolved, and 0.51 g (1.35 mmol) of PCH7 was added. Then, it was made to react at room temperature for 1 hour. Further, 0.79 g (5.27 mmol) of Me4APhA was added and reacted at 40 ° C. for 24 hours under a nitrogen atmosphere. As a result, a polymer (polymer solution: PRef-2) having a concentration of 15% by mass and a viscosity of 280 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 37200.

Comparative Example 3
CBDA / p-PDA, PCH7
In a 50 ml two-necked flask equipped with a nitrogen introduction tube and a stirring bar, p-PDA (1.00 g, 9.24 mmol) and PCH7 (0.88 g, 2.31 mmol) were weighed, and NMP (23.12 g) was added and dissolved. Then, 2.20 g (11.20 mmol) of CBDA was added and reacted at room temperature for 24 hours under a nitrogen atmosphere. As a result, a polymer (polymer solution: PRef-3) having a concentration of 15% by mass and a viscosity of 380 mPas was obtained. The weight average molecular weight of the obtained polymer was Mw: 44200.

<Adjustment of liquid crystal alignment agent>
Example 7
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (P-1) obtained in Example 3 was weighed, and NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-1) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Example 8
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (P-2) obtained in Example 4 was weighed, NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-2) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Example 9
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (P-3) obtained in Example 5 was measured, and 2.5 g of NMP, 5.0 g of GBL and 7.5 g of BCS were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-3) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Example 10
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (P-4) obtained in Example 6 was weighed, NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-4) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Comparative Example 4
In a 50 ml Erlenmeyer flask equipped with a stirrer, 10.0 g of the polymer (PRef-1) obtained in Comparative Example 1 was measured, and NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-5) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Comparative Example 5
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (PRef-2) obtained in Comparative Example 2 was measured, and NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-6) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Comparative Example 6
In a 50 ml Erlenmeyer flask equipped with a stir bar, 10.0 g of the polymer (PRef-3) obtained in Comparative Example 3 was measured, and NMP 2.5 g, GBL 5.0 g, and BCS 7.5 g were added, and then at room temperature. Stir for 30 minutes. As a result, a liquid crystal aligning agent (AL-7) having a solid content of 6.0% by mass, NMP 44% by mass, GBL 20% by mass, and BCS 30% by mass was obtained.

Using the liquid crystal aligning agents (AL-1 to AL-4) of Examples 7 to 10 and the liquid crystal aligning agents (AL-5 to AL-7) of Comparative Examples 4 to 6, a liquid crystal aligning film was formed based on the following method. evaluated.

<Evaluation of whitening resistance and applicability (printability)>
One drop of the obtained liquid crystal aligning agent was put on each well-cleaned Cr substrate and left at room temperature of 25 ° C. and humidity of 60%, and the time until whitening (whitening) was measured. Based on the measured time, whitening resistance was evaluated.

After the liquid crystal aligning agent is filtered through a 1.0 μm filter, the applicability test is performed by performing flexographic printing on the washed Cr plate using an alignment film printing machine (“Nongstromer” manufactured by Nissha Printing Co., Ltd.). went.

About 1.0 ml of the liquid crystal aligning agent was dropped on the anilox roll, and the blanking operation was performed 10 times. Then, the printing machine was stopped for 10 minutes, and the printing plate was dried. Thereafter, printing was performed on one Cr substrate, the printed substrate was left on a hot plate at 70 ° C. for 5 minutes, the coating film was temporarily dried, and the film state was observed. The film thickness unevenness and the film thickness unevenness of the edge portion were mainly observed by visual observation and magnification of 50 times with an optical microscope (“ECLIPSE ME600” manufactured by Nikon Corporation).

<Evaluation of liquid crystal orientation, voltage holding ratio, and pretilt angle>
[Observation of liquid crystal alignment and production of liquid crystal cell]
After filtering the liquid crystal aligning agent through a 1.0 μm filter, a substrate with an electrode (a glass substrate with a size of 30 mm wide × 40 mm long and 1.1 mm thick. The electrode is a rectangle 10 mm wide × 40 mm long, It was applied by spin coat printing to an ITO electrode having a thickness of 35 nm. After drying on a hot plate at 50 ° C. for 5 minutes, baking was performed in an IR oven at 180 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. This membrane is rubbed with a rayon cloth (YA-20R manufactured by Yoshikawa Chemical Industries) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, indentation length: 0.4 mm), and then in pure water for 1 minute. The substrate was washed by irradiating with ultrasonic waves, water droplets were removed by air blow, and then dried at 80 ° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film.

Prepare two substrates with the above-mentioned liquid crystal alignment film, spray a 4 μm spacer on the surface of one liquid crystal alignment film, print a sealant on it, and reverse the rubbing direction of the other substrate. After laminating with the direction and the film surfaces facing each other, the sealing agent was cured to produce an empty cell. MLC-2041 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. Thereafter, the liquid crystal alignment was observed, and then the liquid crystal cell was heated at 110 ° C. for 1 hour and left at 23 ° C. overnight to obtain a liquid crystal cell for measuring voltage holding ratio.

Using the voltage holding ratio measurement liquid crystal cell obtained by the above procedure, a voltage of 1 V was applied for 60 μs at a temperature of 60 ° C., and the voltage after 166.7 ms was measured. Was calculated as a voltage holding ratio. The voltage holding ratio was measured using a VHR-1 voltage holding ratio measuring device manufactured by Toyo Technica.

[Evaluation of pretilt angle]
For measurement of the pretilt angle, an Axo Scan Mueller matrix polarimeter manufactured by Optometrics was used.

Table 3 shows the results of the various evaluations described above.

The liquid crystal aligning agents of Examples 7 to 10 have excellent whitening resistance and good printability as compared with the comparative examples. Since Comparative Example 6 is a polyamic acid-based material, it is a material system with good whitening resistance and printability. In Examples 7 to 10, it is expected that characteristics equivalent to or higher than those of Comparative Example 5 can be obtained in terms of whitening resistance and printability.

Also, the liquid crystal cells obtained using the liquid crystal aligning agents of Examples 7 to 10 have a high pretilt angle and a high voltage holding ratio. For example, since the side chain-containing monomer used in this example contributes to increasing the pretilt angle of the liquid crystal, the target pretilt angle can be adjusted by variously selecting the structure and amount of the side chain-containing monomer monomer. Expected to be able to get. The liquid crystal alignment film which is one embodiment of the present invention is considered very promising as a liquid crystal alignment film that can be obtained by baking at a low temperature. It should be noted that the liquid crystal alignment film and the liquid crystal display element could be suitably obtained using any of the liquid crystal alignment agents of Examples 7 to 10.

The liquid crystal display element produced using the liquid crystal aligning agent of this invention can be made into a highly reliable liquid crystal display device, TN liquid crystal display element, STN liquid crystal display element, TFT liquid crystal display element, VA liquid crystal display element, OCB. It can be suitably used for display elements of various systems such as liquid crystal display elements.

Claims (10)

1. A liquid crystal aligning agent using a polymer obtained from a diamine derivative represented by the following formula (1), a diisocyanate derivative, and a monomer selected from diamine or diisocyanate having a specific side chain.
   

   

   In the formula, A represents a divalent organic group selected from an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C each independently represent a single bond or an aliphatic carbon group having 1 to 5 carbon atoms. Indicates a hydrogen group. R ₁ represents an alkyl group having 1 to 4 carbon atoms and may be branched. R ₂ represents 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.
2. The liquid crystal aligning agent of Claim 1 with which the monomer containing the said specific side chain is represented by the following Formula (2).
   

   

   In the formula, N represents an amino group or an isocyanate group, R ₃ represents a single bond or a divalent organic group, and X ¹ , X ² , and X ³ each independently represent a benzene ring or a cyclohexane ring. , P, q and r each independently represents an integer of 0 or 1, and R ₄ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a divalent having 12 to 25 carbon atoms having a steroid skeleton. An organic group is shown.
3. The liquid crystal aligning agent of Claim 2 whose said diamine derivative is a diamino compound represented by the following Formula (3).
   

   

   In the formula, Ar represents an aryl group, and D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. R ₁ , R ₂ , Ra and Rb are synonymous with the above R ₁ , R ₂ , Ra and Rb.
4. 4. The liquid crystal aligning agent according to claim 3, wherein the diamine derivative is a diamino compound represented by the following formula (3-a).
   

   

   Wherein, D and _{R 1} have the same meanings as D and _{R 1} above.
5. A polymer obtained from a diamino compound represented by the following formula (3-1), a diisocyanate derivative, and a monomer selected from diamine or diisocyanate having a specific side chain.
   

   

   In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms and may be branched. 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, wherein the monomer containing the specific side chain is represented by the following formula (2).
   

   

   In the formula, N represents an amino group or an isocyanate group, R ₃ represents a single bond or a divalent organic group, and X ¹ , X ² , and X ³ each independently represent a benzene ring or a cyclohexane ring. , P, q and r each independently represents an integer of 0 or 1, and R ₄ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a divalent having 12 to 25 carbon atoms having a steroid skeleton. An organic group is shown.
7. The polymer according to claim 6, wherein the diisocyanate derivative has at least one of structures represented by the following formulas (4-1) to (4-13).
   

   

   In the formula, R ₅ and R ₆ each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
8. A liquid crystal aligning agent using the polymer according to any one of claims 5 to 7.
9. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 4 and 8.
10. A liquid crystal display element using the liquid crystal alignment film according to claim 9.