JP7410457B2 - Polyurea copolymer, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same - Google Patents

Description

The present invention relates to a polyurea copolymer, a liquid crystal alignment agent, 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 crystal in a certain direction. Currently, the main liquid crystal alignment films used industrially are made by coating a substrate with a polyimide-based liquid crystal alignment agent made of polyamic acid (also called polyimide precursor or polyamic acid) or polyimide solution, and then baking it. A film is formed. Further, when liquid crystal is aligned parallel or oblique to the substrate surface, a surface stretching process (rubbing process) by rubbing is performed after film formation. As an alternative to rubbing treatment, a method using an anisotropic photochemical reaction such as irradiation with polarized ultraviolet light has also been proposed.

A number of techniques have been proposed to improve the display characteristics of liquid crystal display elements. For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2-287324) proposes the use of a polyimide resin having a specific repeating structure in order to obtain a high voltage holding ratio (VHR). Further, 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.

Japanese Patent Application Publication No. 2-287324 Japanese Patent Application Publication No. 10-104633

Examples of materials used for the liquid crystal alignment film include polyimide precursors such as polyamic acids and polyamic acid esters, and polyimides obtained by dehydrating them by firing or chemical reactions. Among these, polyamic acid is easy to synthesize and has excellent solubility in solvents, so it is possible to obtain a liquid crystal aligning agent with excellent coating properties and film-forming properties on substrates. However, due to its structure, polyamic acid is easily decomposed by hydrolysis, etc., so the liquid crystal alignment film obtained using it has long-term reliability (high voltage holding rate and low residual voltage). etc.) is difficult to secure.

On the other hand, soluble polyimide (polyimide soluble in a solvent obtained by dehydration reaction of polyamic acid) has excellent chemical stability and heat resistance, so liquid crystal alignment films obtained using soluble polyimide can be used reliably over a long period of time. It becomes easier to secure sex. However, soluble polyimide has few choices of solvents that can be dissolved in it, and therefore, the solvents that can be used are limited.As a result, when soluble polyimide is used, precipitation occurs during coating and film formation, and the coating film are prone to defects.

Here, by using polyimide with low electrical resistance, it is advantageous to improve the electrical characteristics of the resulting liquid crystal display film (for example, the accumulated charge of the liquid crystal display film (voltage remains unchanged even after the voltage application is removed). This refers to the charge that remains and, as a result, accumulates. However, in this case, the liquid crystal display film is likely to be colored due to the formation of a charge transfer complex (CT complex), so the liquid crystal display obtained using such a liquid crystal display film is Reproducibility and contrast tend to deteriorate.

In recent years, the demand for ultra-high definition liquid crystal displays such as 4K and 8K has been increasing, and liquid crystal displays are increasingly required to have high contrast, high color reproducibility, and the like. Furthermore, research on liquid crystal displays using quantum dots (QDs) and the like is also progressing. Therefore, the materials for forming the liquid crystal alignment film include, for example, materials that are unlikely to cause deterioration of image quality or defects depending on the usage environment, materials that can be fired at low temperatures, materials with high transparency, and materials that prevent burn-in at high and low temperatures. There is a growing demand for materials that can In the future, as liquid crystal displays become more multi-functional, larger, higher definition, and the environments in which they are used become more diverse, there will be a need to search for methods that can solve each problem and improve various characteristics. ing.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal alignment film that quickly relieves accumulated charges and is excellent in various properties including transparency. Another object of the present invention is to provide a liquid crystal display element using the above liquid crystal alignment film. Further, it is an object of the present invention to provide a liquid crystal aligning agent that can obtain the above-mentioned liquid crystal aligning film, can be fired at a low temperature, and has good printability (solubility of the resulting polymer in an organic solvent). Another object of the present invention is to provide a polyurea copolymer from which the above liquid crystal aligning agent can be obtained.

As a result of intensive research, the present inventor found that a polyurea copolymer having a specific structure and a liquid crystal aligning agent using the same are effective in achieving the above object, and completed the present invention. reached. Note that the above polyurea copolymer is new, and the monomer for obtaining the above polyurea copolymer also contains a new compound.

That is, the present invention provides the following 1. ~7. The gist is:

1. A polyurea copolymer having a structure represented by the following formula (1).

式中、Ｒ_１は炭素数１～４のアルキル基を示し、分岐していてもよく、Ｒ_２は水素原子、炭素数１～４の脂肪族炭化水素基、又は下式（１－１）で表される有機基を示す。Ｒａ及びＲｂはそれぞれ独立して、水素原子、又は炭素数１～２の脂肪族炭化水素基を示す。Ｘは下式（Ｓ）で表される二価の有機基を示し、Ｙは二価の有機基を示す。

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, which may be branched, and R ₂ is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, or the following formula (1-1) Indicates an organic group represented by Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms. X represents a divalent organic group represented by the following formula (S), and Y represents a divalent organic group.

式中、黒点は窒素原子への結合箇所を意味し、Ｒ_１、Ｒａ及びＲｂは上記のＲ_１、Ｒａ及びＲｂと同義である。

In the formula, the black dots mean bonding sites to the nitrogen atom, and R ₁ , Ra and Rb have the same meanings as R ₁ , Ra and Rb above.

式中、Ｑ^１及びＱ^２は式（Ｑ１－１）、式（Ｑ１－２）及び単結合から選ばれる一種を示す。ただし、Ｑ^１及びＱ^２の少なくとも１つは、（Ｑ１－１）及び（Ｑ１－２）から選ばれる一種を示す。ｑ１とｑ２はそれぞれ独立に０又は１を示し、Ｌ^１及びＬ^２は水素原子を示す。ただし、Ｑ^１が式（Ｑ１－１）である場合は、Ｌ^１及びＬ^２は一緒になって単結合を形成してもよい。黒点は窒素原子への結合箇所を意味する。

In the formula, Q ¹ and Q ² represent one selected from formula (Q1-1), formula (Q1-2), and a single bond. However, at least one of Q ¹ and Q ² represents one type selected from (Q1-1) and (Q1-2). q1 and q2 each independently represent 0 or 1, and L ¹ and L ² represent a hydrogen atom. However, when Q ¹ is the formula (Q1-1), L ¹ and L ² may be combined to form a single bond. Black dots indicate bonding points to nitrogen atoms.

式中、Ｒ_５は水素原子、ｔ－ブトキシカルボニル基、又は炭素数１～６のアルキル基を示す。Ｒ_５は、炭素数１～６のアルキル基を示す場合、分岐していてもよく、環を形成していてもよく、また不飽和結合を有していてもよい。Ｅは－ＮＨ－、－ＮＭｅ－、－Ｓ－、又は－Ｏ－を示し、Ｆ及びＧはそれぞれ独立して、ＣＨ、又は窒素原子を示す。

In the formula, R ₅ represents a hydrogen atom, a t-butoxycarbonyl group, or an alkyl group having 1 to 6 carbon atoms. When R ₅ represents an alkyl group having 1 to 6 carbon atoms, it may be branched, form a ring, or have an unsaturated bond. E represents -NH-, -NMe-, -S-, or -O-, and F and G each independently represent CH or a nitrogen atom.

2. The above X represents a divalent organic group represented by the following formula, 1. The polyurea copolymer described in .

式中、黒点は窒素原子への結合箇所を意味する。

In the formula, black dots mean bonding sites to nitrogen atoms.

3. 1. The above Y is a divalent organic group represented by the above formula (S) or a divalent organic group represented by the following formula (Q-1). Or 2. The polyurea copolymer described in .

式中、Ａは脂肪族炭化水素基又は芳香族炭化水素基の、２価の有機基を示し、Ｂ及びＣはそれぞれ独立して、単結合、又は炭素数１～５の脂肪族炭化水素基を示す。黒点は窒素原子への結合箇所を意味する。

In the formula, A represents a divalent organic group such as an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C are each independently a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. shows. Black dots indicate bonding points to nitrogen atoms.

4. 1. Said Y is a divalent organic group represented by the following formula (Q-2). ~3. The polyurea copolymer according to any one of .

式中、Ｄは単結合、又は炭素数１～５の炭化水素基を示す。黒点は窒素原子への結合箇所を意味する。

In the formula, D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. Black dots indicate bonding points to nitrogen atoms.

5.1. ~4. A liquid crystal aligning agent using the polyurea copolymer described in any one of the above.

6. 5. A liquid crystal aligning film obtained from the liquid crystal aligning agent described in .

7.6. A liquid crystal display element using the liquid crystal alignment film described in .

According to the present invention, it is possible to provide a liquid crystal display film in which accumulated charges are quickly relaxed and which is excellent in various properties including transparency. Further, according to the present invention, it is possible to provide a liquid crystal display element using the above liquid crystal display film. Further, according to the present invention, it is possible to obtain the liquid crystal display element and the liquid crystal alignment film, and also to provide a liquid crystal aligning agent that can be fired at low temperatures and has good printability. Furthermore, according to the present invention, a novel polyurea copolymer for obtaining the above-mentioned liquid crystal aligning agent can be provided.

A polyurea copolymer that is one embodiment of the present invention has a structure represented by the following formula (1).

式中、Ｒ_１は炭素数１～４のアルキル基を示し、分岐していてもよく、Ｒ_２は水素原子、炭素数１～４の脂肪族炭化水素基、又は下式（１－１）で表される有機基を示す。Ｒａ及びＲｂはそれぞれ独立して、水素原子、又は炭素数１～２の脂肪族炭化水素基を示す。Ｘは下式（Ｓ）で表される二価の有機基を示し、Ｙは二価の有機基を示す。

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, which may be branched, and R ₂ is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, or the following formula (1-1) Indicates an organic group represented by Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms. X represents a divalent organic group represented by the following formula (S), and Y represents a divalent organic group.

式中、黒点は窒素原子への結合箇所を意味し、Ｒ_１、Ｒａ及びＲｂは上記のＲ_１、Ｒａ及びＲｂと同義である。

In the formula, the black dots mean bonding sites to the nitrogen atom, and R ₁ , Ra and Rb have the same meanings as R ₁ , Ra and Rb above.

式中、Ｑ^１及びＱ^２は式（Ｑ１－１）、式（Ｑ１－２）及び単結合から選ばれる一種を示す。ただし、Ｑ^１及びＱ^２の少なくとも１つは、（Ｑ１－１）及び（Ｑ１－２）から選ばれる一種を示す。ｑ１とｑ２はそれぞれ独立に０又は１を示し、Ｌ^１及びＬ^２は水素原子を示す。ただし、Ｑ^１が式（Ｑ１－１）である場合は、Ｌ^１及びＬ^２は一緒になって単結合を形成してもよい。黒点は窒素原子への結合箇所を意味する。

In the formula, Q ¹ and Q ² represent one selected from formula (Q1-1), formula (Q1-2), and a single bond. However, at least one of Q ¹ and Q ² represents one type selected from (Q1-1) and (Q1-2). q1 and q2 each independently represent 0 or 1, and L ¹ and L ² represent a hydrogen atom. However, when Q ¹ is the formula (Q1-1), L ¹ and L ² may be combined to form a single bond. Black dots indicate bonding points to nitrogen atoms.

式中、Ｒ_５は水素原子、ｔ－ブトキシカルボニル基、又は炭素数１～６のアルキル基を示す。Ｒ_５は、炭素数１～６のアルキル基を示す場合、分岐していてもよく、環を形成していてもよく、また不飽和結合を有していてもよい。Ｅは－ＮＨ－、－ＮＭｅ－、－Ｓ－、又は－Ｏ－を示し、Ｆ及びＧはそれぞれ独立して、ＣＨ、又は窒素原子を示す。

In the formula, R ₅ represents a hydrogen atom, a t-butoxycarbonyl group, or an alkyl group having 1 to 6 carbon atoms. When R ₅ represents an alkyl group having 1 to 6 carbon atoms, it may be branched, form a ring, or have an unsaturated bond. E represents -NH-, -NMe-, -S-, or -O-, and F and G each independently represent CH or a nitrogen atom.

By using a polyurea copolymer having an organic group represented by formula (S), the resulting liquid crystal alignment film can obtain desired properties (e.g., quick relaxation of accumulated charges, excellent transparency, etc.). It becomes easier.

From the viewpoint of easily achieving the object of the present invention, in formula (1), Y is a divalent organic group represented by formula (S) or a divalent organic group represented by formula (Q-1) below. It is preferably an organic group, and more preferably Y is a divalent organic group represented by the following formula (Q-2).

式中、Ａは脂肪族炭化水素基又は芳香族炭化水素基の、２価の有機基を示し、Ｂ及びＣはそれぞれ独立して、単結合、又は炭素数１～５の脂肪族炭化水素基を示す。黒点は窒素原子への結合箇所を意味する。

In the formula, A represents a divalent organic group such as an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C are each independently a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. shows. Black dots indicate bonding points to nitrogen atoms.

式中、Ｄは単結合、又は炭素数１～５の炭化水素基を示す。黒点は窒素原子への結合箇所を意味する。

In the formula, D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. Black dots indicate bonding points to nitrogen atoms.

The above polyurea copolymer can be obtained by reacting a predetermined diamine derivative (hereinafter sometimes referred to as "diamine") and a predetermined diisocyanate derivative (hereinafter sometimes referred to as "diisocyanate"). . In formula (1), for example, X is derived from diisocyanate and Y is derived from diamine. Therefore, X and Y can have various structures depending on the structures of the diamine and diisocyanate that are the raw materials for the polyurea copolymer.

<Diamine usable in the present invention (diamine represented by formula (2))>
One of the diamines that can be used in the present invention is represented by formula (2).

式中、Ａは脂肪族炭化水素基又は芳香族炭化水素基の、二価の有機基を示し、Ｂ及びＣはそれぞれ独立して、単結合、又は炭素数１～５の脂肪族炭化水素基を示す。Ｒ_１は炭素数１～４のアルキル基を示し、分岐していてもよい。Ｒ_２は水素原子、炭素数１～４の脂肪族炭化水素基、又は式（１－１）で表される有機基を示す。Ｒａ及びＲｂはそれぞれ独立して、水素原子、又は炭素数１～２の脂肪族炭化水素基を示す。

In the formula, A represents a divalent organic group such as an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C are each independently a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. shows. 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 formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms.

It is thought that if the above-mentioned diamine is used, the obtained liquid crystal aligning agent and liquid crystal aligning film will be able to easily obtain the desired properties. From the viewpoint of being able to obtain a liquid crystal alignment film with excellent monomer polymerization reactivity, heat resistance, and liquid crystal alignment properties, in formula (2), A is an aromatic hydrocarbon group and B is a carbon number 1. -3 aliphatic hydrocarbon groups, C being a single bond, is more preferred. A specific example of formula (2) is the following formula (3).

式中、Ａｒはアリール基を示し、Ｄは単結合、炭素数１～５の炭化水素基を示す。Ｒ_１、Ｒ_２、Ｒａ及びＲｂは上記のＲ_１、Ｒ_２、Ｒａ及びＲｂと同義である。

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 have the same meanings as R ₁ , R ₂ , Ra and Rb above.

Considering the following aspects: it is easy to obtain a reagent for synthesizing diamine, the reactivity with diisocyanate is good, and the physical properties of the resulting polyurea copolymer are good, the formula ( In 3), Ar is preferably a phenyl group, and R ₂ is preferably a hydrogen atom. Therefore, formula (3) preferably has a structure represented by the following formula (3-a)'. Among these, in formula (3), it is preferable that Ra and Rb are each hydrogen atoms. Therefore, formula (3) is particularly preferably represented by formula (3-a). Note that formula (Q-2) is, for example, a structure derived from formula (3-a).

式中、Ｄ及びＲ_１は上記のＤ及びＲ_１と同義である。

In the formula, D and R ₁ have the same meanings as D and R ₁ above.

From the viewpoint of being able to obtain the desired monomer suitably and easily achieving all of the above characteristics, the above formula (3-a)' is preferably expressed by the following formula (3-1). be done.

式中、Ｂ、Ｒ_１、Ｒａ及びＲｂは上記のＢ、Ｒ_１、Ｒａ及びＲｂと同義である。式（３－１）中、Ｂが炭素数１及び２であり、Ｒａ及びＲｂがそれぞれ水素原子であると、式（３－１）は、式（３－１ａ）及び式（３－１ｂ）で表される。

In the formula, B, R ₁ , Ra and Rb have the same meanings as B, R ₁ , Ra and Rb above. In formula (3-1), when B has 1 and 2 carbon atoms, and Ra and Rb are hydrogen atoms, respectively, formula (3-1) can be converted to formula (3-1a) and formula (3-1b). It is expressed as

式中、Ｒ_１は上記のＲ_１と同義である。

In the formula, R ₁ has the same meaning as R ₁ above.

The above-mentioned diamine plays an important role in the solubility of the polyurea polymer, the storage stability of the varnish contained in the liquid crystal aligning agent, the printability of the liquid crystal aligning agent, and the reliability when used as a liquid crystal aligning film. The content of the diamine is, for example, about 10 mol% to 100 mol%, more preferably about 30 mol% to 70 mol%, of the total amount of diamine used in the present invention. However, the above-mentioned diamine only needs to be included in the polyurea polymer, and its content is not limited to the above-mentioned value.

Moreover, the specific example of the diamine represented by Formula (2) is not limited to the diamine represented by Formula (3). The above polyurea polymer can be synthesized within a range that does not impair the effects of the present invention (for example, the ability to quickly relax accumulated charges and obtain a liquid crystal alignment film that has excellent various properties such as transparency). In this case, a part of the diamine represented by formula (2) or formula (3) may be replaced with a diamine represented by formula (5) described later.

<Diamine that can be used in the present invention (diamine having a structure represented by formula (S))>
One of the diamines that can be used in the present invention has a structure represented by formula (S). The diamine having the structure represented by formula (S) and the diamine represented by formula (2) can be used in combination.

式中、Ｑ^１及びＱ^２は式（Ｑ１－１）、式（Ｑ１－２）及び単結合から選ばれる一種を示す。ただし、Ｑ^１及びＱ^２の少なくとも１つは、（Ｑ１－１）及び（Ｑ１－２）から選ばれる一種を示す。ｑ１とｑ２はそれぞれ独立に０又は１を示し、Ｌ^１及びＬ^２は水素原子を示す。ただし、Ｑ^１が式（Ｑ１－１）である場合は、Ｌ^１及びＬ^２は一緒になって単結合を形成してもよい。黒点は窒素原子への結合箇所を意味する。

In the formula, Q ¹ and Q ² represent one selected from formula (Q1-1), formula (Q1-2), and a single bond. However, at least one of Q ¹ and Q ² represents one type selected from (Q1-1) and (Q1-2). q1 and q2 each independently represent 0 or 1, and L ¹ and L ² represent a hydrogen atom. However, when Q ¹ is the formula (Q1-1), L ¹ and L ² may be combined to form a single bond. Black dots indicate bonding points to nitrogen atoms.

式中、Ｒ_５は水素原子、ｔ－ブトキシカルボニル基、又は炭素数１～６のアルキル基を示す。Ｒ_５は、炭素数１～６のアルキル基を示す場合、分岐していてもよく、環を形成していてもよく、また不飽和結合を有していてもよい。Ｅは－ＮＨ－、－ＮＭｅ－、－Ｓ－、又は－Ｏ－を示し、Ｆ及びＧはそれぞれ独立して、ＣＨ、又は窒素原子を示す。

In the formula, R ₅ represents a hydrogen atom, a t-butoxycarbonyl group, or an alkyl group having 1 to 6 carbon atoms. When R ₅ represents an alkyl group having 1 to 6 carbon atoms, it may be branched, form a ring, or have an unsaturated bond. E represents -NH-, -NMe-, -S-, or -O-, and F and G each independently represent CH or a nitrogen atom.

The diamine having the structure represented by formula (S) is not particularly limited as long as it contains the structure. However, from the viewpoints that the diamine can be easily synthesized, the reagent for synthesizing the diamine can be easily obtained, the diamine has high solubility, etc., specific examples of diamines that are particularly preferred Examples of formulas (S-4) to (S-13) include formulas (S-4) to (S-13).

Note that when the diisocyanate described below has a structure represented by formula (S), these diamines may not be used. By introducing the structure represented by formula (S) into the polyurea copolymer, the resistivity of the liquid crystal alignment film can be lowered, and the rate of relaxation of accumulated charges in the liquid crystal alignment film can be increased. On the other hand, if the amount introduced is too large, there is a risk that the accumulated charge will increase. The amount introduced is preferably about 0 mol% to 90 mol%, more preferably about 30 mol% to 70 mol%. Depending on the type of diamine used, there is a possibility that a liquid crystal alignment agent and a liquid crystal alignment film having even better properties can be obtained by increasing or decreasing the amount used.

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

式中、Ｘは２価の有機基を示す。Ｘは、例えば、ジアミンの項目で上述した式（Ｓ）で表される構造である。すなわち、本発明では、式（Ｓ）で表される構造を有するジイソシアネートを使用することができる。式（Ｓ）で表される構造を有するジイソシアネートは、式（Ｓ）で表される構造を有するジアミンにホスゲン等を反応させて誘導される。従って、式（Ｓ）で表される構造を有するジアミンを入手することができれば、上記ジイソシアネートは誘導可能である。

In the formula, X represents a divalent organic group. X is, for example, a structure represented by the formula (S) described above in the diamine section. That is, in the present invention, a diisocyanate having a structure represented by formula (S) can be used. A diisocyanate having a structure represented by formula (S) is derived by reacting a diamine having a structure represented by formula (S) with phosgene or the like. Therefore, if a diamine having the structure represented by formula (S) can be obtained, the above diisocyanate can be derived.

The structure represented by formula (S) plays an important role in obtaining the effects of the present invention. Therefore, when a structure represented by formula (S) is introduced by using a diisocyanate, the amount to be introduced is not limited. However, the amount introduced is preferably 10 mol% to 100 mol%, more preferably 50 mol% to 80 mol%. Depending on the type of diisocyanate used, there is a possibility that a liquid crystal alignment agent and a liquid crystal alignment film having even better properties can be obtained by increasing or decreasing the amount used. Note that when the diamine has a structure represented by formula (S), these diisocyanates may not be used.

<Other diamines>
In obtaining the above-mentioned polyurea copolymer, a part of the above-mentioned diamine that can be used in the present invention may be replaced with a diamine (other diamine) represented by the following formula (5). In general, there are many types of diamines, and many compounds have organic groups with various functions, so it is possible to add further effects to the polyurea copolymer by using other diamines in combination. There is. On the other hand, if the amount of other diamines introduced is too large, the desired properties may not be obtained. About 50 mol% is preferable.

式中、Ｙは２価の有機基であり、Ｙの構造の例は、下式（Ｙ－１）～式（Ｙ－１４７）のように列挙されるが、これらに限定されない。Ｒ_６はそれぞれ独立して、水素原子、メチル基、又はエチル基を示す。なお、ジアミンと、テトラカルボン酸二無水物と、の反応ではポリアミド酸を与え、ジアミンと、ジイソシアネートと、の反応ではポリウレアを与える。

In the formula, Y is a divalent organic group, and examples of the structure of Y are listed as the following formulas (Y-1) to (Y-147), but are not limited to these. R ₆ each independently represents a hydrogen atom, a methyl group, or an ethyl group. Note that the reaction between diamine and tetracarboxylic dianhydride gives polyamic acid, and the reaction between diamine and diisocyanate gives polyurea.

式（Ｙ－１０８）～式（Ｙ－１１２）中、Ａ_１は炭素数２～２４の、アルキル基又はフッ素含有アルキル基を示す。

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.

式（Ｙ－１１３）～式（Ｙ－１１４）中、Ａ_２は－Ｏ－、－ＯＣＨ_２－、－ＣＨ_２Ｏ－、－ＣＯＯＣＨ_２－、又は－ＣＨ_２ＯＣＯ－を示し、Ａ_３は炭素数１～２２の、アルキル基、アルコキシ基、フッ素含有アルキル基又はフッ素含有アルコキシ基を示す。

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 is Indicates an alkyl group, alkoxy group, fluorine-containing alkyl group, or fluorine-containing alkoxy group having 1 to 22 carbon atoms.

式（Ｙ－１１５）～式（Ｙ－１１７）中、Ａ_４は－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＯＣＨ_２－、－ＣＨ_２ＯＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、又は－ＣＨ_２－を示し、Ａ_５は炭素数１～２２の、アルキル基、アルコキシ基、フッ素含有アルキル基又はフッ素含有アルコキシ基を示す。

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

式（Ｙ－１１８）～式（Ｙ－１１９）中、Ａ_６は－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＯＣＨ_２－、－ＣＨ_２ＯＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、－ＣＨ_２－、－Ｏ－、又は－ＮＨ－を示し、Ａ_７はフッ素基、シアノ基、トリフルオロメタン基、ニトロ基、アゾ基、ホルミル基、アセチル基、アセトキシ基、又は水酸基を示す。

In formulas (Y-118) to (Y-119), A ₆ is -COO-, -OCO-, -CONH-, -NHCO-, -COOCH ₂ -, -CH ₂ OCO-, -CH ₂ O- , -OCH ₂ -, -CH ₂ -, -O-, or -NH-, and A ₇ is 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 indicates a hydroxyl group.

式（Ｙ－１２０）～式（Ｙ－１２１）中、Ａ_８は炭素数３～１２のアルキル基を示し、１，４－シクロヘキシレンのシス－トランス異性は、それぞれトランス異性体である。

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

式（Ｙ－１２２）～式（Ｙ－１２３）中、Ａ_９は炭素数３～１２のアルキル基を示し、１，４－シクロヘキシレンのシス－トランス異性は、それぞれトランス異性体である。

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

式（Ｙ－１３２）～式（Ｙ－１３７）中、Ａ_１２は－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＨ_２－、－Ｏ－、－ＣＯ－、又は－ＮＨ－を示し、Ａ_１３は炭素数１～２２の、アルキル基又はフッ素含有アルキル基を示す。

In formulas (Y-132) to (Y-137), A ₁₂ is -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.

式（Ｙ－１４０）、式（Ｙ－１４４）及び式（Ｙ－１４５）中、ｎは１～１０の整数を示す。

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

<Other diisocyanates>
In obtaining the above polyurea copolymer, some of the diisocyanates that can be used in the present invention are diisocyanates represented by formulas (4-1) to (4-11) and formula (4-13) (other diisocyanates). ) may be replaced.

When using aliphatic diisocyanates represented by formulas (4-1) to (4-5), aromatic diisocyanates represented by formulas (4-6) to (4-11) and formula (4-13) are used. The resulting polyurea copolymer is better soluble in a solvent than when a group diisocyanate is used. On the other hand, the aromatic diisocyanate reacts better with diamines than the aliphatic diisocyanate. For example, aromatic diisocyanates as shown in formulas (4-6) and (4-7) react favorably with diamines and can improve the heat resistance of the resulting liquid crystal alignment film.

Formula (4) is a compound with high versatility for obtaining the polyurea copolymer, and the resulting polyurea copolymer has good properties. Formula (4-7), formula (4-8), formula (4-9), or formula (4-10) is preferred. Further, formula (5) is preferably formula (4-13) from the viewpoint of improving the liquid crystal orientation of the obtained liquid crystal alignment film.

Various other diisocyanates can be used depending on the properties desired. However, if the amount of diisocyanate that can be used in the present invention is replaced with other diisocyanates is too large, the desired properties may not be obtained. It is preferably about 0 to 50 mol% based on the total mole of diisocyanate.

<Reaction solution>
The reaction solution (organic solvent used in the reaction to obtain the polyurea copolymer) is not particularly limited as long as it can dissolve the polyurea copolymer. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, Dimethyl sulfone, hexamethyl sulfoxide, 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, 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 acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3- Ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethylpropanamide, Examples include 3-ethoxy-N,N-dimethylpropanamide and 3-butoxy-N,N-dimethylpropanamide. These may be used alone or in combination of two or more. As long as the polyurea copolymer does not precipitate, even a solution that does not dissolve the polyurea copolymer can be used by mixing it with the reaction solution.

Further, since water in the reaction solution inhibits the polymerization reaction and further causes hydrolysis of the produced polyurea copolymer, it is preferable to use a reaction solution that has been dehydrated and dried. When diisocyanate and diamine are reacted in a reaction solution, the reaction solution in which the diamine is dispersed or dissolved is stirred, and the diisocyanate is added as it is or after being dispersed or dissolved in the reaction solution, or conversely, the diisocyanate is added by dispersing or dissolving it in the reaction solution. Alternatively, a method of adding diamine to the dissolved reaction solution, a method of alternately adding diisocyanate and diamine to the reaction solution, etc., and any of these methods may be used.

In addition, when the diisocyanate or diamine consists of multiple types of compounds, they may be reacted in a pre-mixed state, or may be reacted individually in sequence, and furthermore, low molecular weight compounds reacted individually may be mixed and reacted to form a high molecular weight compound. It can also be used as a body. The polymerization temperature at that time can be selected from any temperature from -20°C to 150°C, but preferably from -5°C to 100°C. In addition, the reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polyurea copolymer, and if the concentration is too high, the viscosity of the reaction solution will become too high, making it difficult to stir uniformly. Therefore, the total concentration of diisocyanate and diamine in the reaction solution is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass. It is also possible to carry out the reaction at a high concentration in the initial stage, and then add the reaction solution.

In the polyurea polymerization reaction, the ratio between the total number of moles of diisocyanate and the total number of moles of diamine is preferably from 0.8 to 1.2. As in normal polycondensation reactions, the closer this molar ratio is to 1.0, the greater the molecular weight of the polyurea copolymer produced.

[Recovery of polyurea copolymer]
In order to recover the produced polyurea copolymer from the reaction solution, the reaction solution may be poured into a poor solvent to precipitate the polyurea copolymer. 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 polyurea copolymer precipitated in a poor solvent can be collected by filtration and then dried under normal pressure or reduced pressure, at room temperature or by heating. Furthermore, by repeating the operations of redissolving the recovered polyurea copolymer in an organic solvent, re-precipitating and re-recovering 2 to 10 times, the amount of impurities in the polyurea copolymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons, etc. It is preferable to use three or more kinds of poor solvents selected from these, since the efficiency of purification will further increase.

The molecular weight of the above-mentioned polyurea copolymer is determined by considering the strength of the coating film obtained from the above-mentioned polyurea copolymer, the ease of work when forming the coating film, the uniformity of the film thickness of the coating film, etc. The weight average molecular weight measured by GPC (Gel Permeation Chromatography) is preferably from 5,000 to 1,000,000, more preferably from 10,000 to 150,000.

<Liquid crystal alignment agent>
The liquid crystal aligning agent that is one embodiment of the present invention is a coating liquid for forming a liquid crystal aligning film, and a resin component for forming a coating film (resin film) is dissolved in an organic solvent. The resin component contains at least one of the above polyurea copolymers. The content of the resin component in the liquid crystal aligning agent is preferably from 2% by mass to 20% by mass, more preferably from 3% by mass to 15% by mass, particularly preferably from 3% by mass to 10% by mass. In the present invention, the polyurea copolymer contained in the resin component may be entirely the above-mentioned polyurea copolymer, or other polymers (other polymers) may be used as long as the polyurea copolymer contained in the resin component is within the spirit of the present invention. ) may be included. The content of other polymers in the resin component is from 0.5% by mass to 15% by mass, preferably from 1% by mass to 10% by mass. Examples of such other polymers include acrylic polymers, methacrylic polymers, novolac resins, polyhydroxystyrene, polyimide precursors, polyimides, polyamides, polyesters, cellulose, polysiloxanes, and the like.

The organic solvent used for the liquid crystal aligning agent is not particularly limited as long as it can dissolve the resin component. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, 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 - Examples include pentanone. These may be used alone or in combination of two or more.

The liquid crystal aligning agent may contain components other than those mentioned above. Examples include solvents and compounds that improve the uniformity of the film thickness and surface smoothness of the coating film formed by applying the liquid crystal alignment agent, or those that improve the adhesion between the liquid crystal alignment film and the substrate. Compounds, etc.

Examples of solvents (poor solvents) that improve the uniformity of film thickness and surface smoothness include solvents with low surface tension, 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, Isobutylene, 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 acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3- Ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 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- Examples include ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate. These poor solvents may be used alone or in combination. When using the above-mentioned poor solvent, it is preferably from 5% by mass to 80% by mass, more preferably from 20% by mass to 60% by mass of the entire organic solvent contained in the liquid crystal aligning agent.

Examples of compounds that improve the uniformity of the film thickness and the smoothness of the coating surface include fluorosurfactants, silicone surfactants, and nonionic surfactants. More specifically, for example, FTOP EF301, EF303, EF352 (manufactured by Tochem Products), Megafac F171, F173, R-30 (manufactured by Dainippon Ink), Florado 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 usage 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, per 100 parts by mass of the resin component contained in the liquid crystal aligning agent. It is.

Specific examples of compounds that improve 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-triethoxysilyl- 1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxy Silane, 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, neo Pentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol , N,N,N',N',-tetraglycidyl-m-xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N',-tetraglycidyl -4,4'-diaminodiphenylmethane and the like.

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

When using a compound that improves the adhesion between the substrate and the film, the amount of the compound used is 0.1 parts by mass to 30 parts by mass per 100 parts by mass of the resin component contained in the liquid crystal aligning agent. is preferable, and more preferably from 1 part by weight to 20 parts by weight. If the amount used is less than the above value, it will be difficult to improve the adhesion, and if it is more than the above value, the liquid crystal orientation may deteriorate.

In addition to the above-mentioned solvents and compounds, the liquid crystal alignment agent may contain dielectric materials for the purpose of changing the electrical properties such as dielectric constant and conductivity of the liquid crystal alignment film, as long as the effects of the present invention are not impaired. A predetermined crosslinking compound may be added for the purpose of increasing the hardness and compactness of the body, conductive material, and even the film when it is made into a liquid crystal aligning film.

<Liquid crystal alignment film/liquid crystal display element>
The liquid crystal aligning agent, which is an embodiment of the present invention, can be applied to a substrate and then baked, and then subjected to alignment treatment by rubbing, light irradiation, etc., or without alignment treatment in vertical alignment applications, etc. can be obtained. 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. Further, it is preferable to use a substrate on which ITO electrodes and the like for driving the liquid crystal are formed, from the viewpoint of simplifying the process of manufacturing the liquid crystal display element. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as the substrate on one side, and a material that reflects light such as aluminum can also be used for the electrodes in this case. The method of applying the liquid crystal aligning agent is not particularly limited, but industrially, spin coat printing, screen printing, offset printing, flexo printing, inkjet printing, etc. are common. Other coating methods include dip, roll coater, slit coater, spinner, etc., and these methods may be used depending on the purpose.

Firing can be carried out at 50°C to 300°C, preferably 80°C to 250°C using 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. The thickness of the coating film is preferably from 5 nm to 300 nm, more preferably from 10 nm to 150 nm, because if it 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 decrease. . When liquid crystals are to be aligned horizontally or obliquely, the coating film after firing is subjected to an alignment treatment such as rubbing or irradiation with polarized ultraviolet rays.

After obtaining a substrate with a liquid crystal alignment film from the liquid crystal alignment agent by the above-described method, a liquid crystal display element which is one embodiment of the present invention can be obtained by producing a liquid crystal cell by a known method. An example of a method for manufacturing a liquid crystal cell is to prepare a pair of substrates on which a liquid crystal alignment film is formed, and sprinkle spacers on the liquid crystal alignment film of one substrate so that the liquid crystal alignment film surface is on the inside. One method is to bond the other substrate together and inject liquid crystal under reduced pressure to seal it. Alternatively, a method may be used in which liquid crystal is dropped onto the surface of a liquid crystal alignment film on which spacers have been sprinkled, and then 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. The liquid crystal display element produced using the liquid crystal aligning agent has excellent reliability and can be suitably used for large-screen, high-definition liquid crystal televisions and the like.

<Synthesis of diamine>
Synthesis example 1
Synthesis of ethyl (4-aminobenzyl) glycinate [NG4ABA]

1st step: Add 105.6 g ( 0.757 mol ) of glycine ethyl hydrochloride, 500 g of THF, and 93.6 g (0.925 mol) of triethylamine to a 1 L 4-necked flask equipped with a nitrogen introduction tube and a reflux tube, and use a mechanical stirrer. After stirring at room temperature for 1 hour, the mixture was heated at a temperature at which THF refluxed (set at 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 the dropwise addition was completed, the reaction was continued for an additional 24 hours. The reaction was terminated when 4-nitrobenzyl bromide disappeared, the precipitated solid was removed by filtration, THF was removed using a rotary evaporator, and the resulting crude product was redissolved in 300.0 g of ethyl acetate. This solution was washed three times with 100 g of pure water, 300 g of a 10% aqueous hydrochloric acid solution was added, stirred for 1 hour, the aqueous layer was collected, and the aqueous layer was washed three times with 100 g of ethyl acetate. Further, 300 g of ethyl acetate was added to the aqueous layer, potassium carbonate was slowly added, the pH was adjusted to about 10, and the mixture was stirred for 1 hour. The organic phase was collected and washed three times with 100 g of pure water. Add anhydrous magnesium sulfate to this organic phase, dry it, filter it, add activated carbon and stir for a while, then remove the activated carbon by filtration, and remove the solvent with a rotary evaporator to obtain the target product (nitro compound), a light yellow. 46.0 g (0.193 mol) of viscous material was obtained. It was confirmed by ¹ H-NMR that the target product was obtained.
^1H NMR (500MHz, _CDCl3 ): δ 8.2 (2H), 7.53 (2H), 4.22 (2H), 3.93 (2H), 3.42 (2H), 1.89 ( 1H), 1.27 (3H)

2nd step Add 45.0 g (0.19 mol) of the nitro compound obtained above, 300.0 g of THF, and 4.5 g of iron-doped platinum carbon to a 500 ml four-necked flask equipped with a nitrogen introduction tube and a stirrer. The inside of the container was carefully replaced with a hydrogen atmosphere, and the reaction was allowed to proceed at room temperature for 24 hours. The reaction was terminated when the raw materials disappeared, and the 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. Thereafter, it was filtered again, the solvent was removed using a rotary evaporator, and then dried using a high vacuum pump to obtain 35.4 g (0.17 mol, yield: 89%) of a pale yellow viscous substance, which was the desired product. It was confirmed by ¹ H-NMR that the target product (NG4ABA) was obtained.
^1H NMR (500MHz, _CDCl3 ): δ 6.99 (2H), 6.63 (2H), 4.15 (2H), 3.70 (2H), 3.38 (2H), 3.00 ( 2H), 1.24 (3H)

Synthesis example 2
Synthesis of ethyl (4-aminophenethyl) glycinate [NG4APhA]

1st step: Add 50 g (0.246 mol) of 4-nitrophenethylamine hydrochloride, 500 g of THF, and 61.1 g (0.604 mol) of triethylamine to a 1 L 4-necked flask equipped with a nitrogen introduction tube and a reflux tube, and use a mechanical stirrer. Stir at room temperature for 1 hour, heat at a temperature at which THF refluxes (set at 70°C), dissolve 25.1 g (0.205 mol) of ethyl 2-chloroacetate in 300 g of THF, and slowly dropwise add this solution. , and further reacted for 24 hours. The reaction was terminated when 2-chloroethyl acetate disappeared (confirmed by HPLC), the precipitated solid was removed by filtration, THF was removed using a rotary evaporator, and the resulting crude product was re-distilled with 500 g of ethyl acetate. Dissolved. This solution was washed three times with 100 g of pure water, 500 g of a 10% aqueous hydrochloric acid solution was added, stirred for 1 hour, the aqueous layer side was collected, and the aqueous layer was washed three times with 100 g of ethyl acetate. Further, 500 g of ethyl acetate was added to the aqueous layer, potassium carbonate was slowly added, the pH was adjusted to about 10, and the mixture was stirred for 1 hour. The organic phase was collected and washed three times with 100 g of pure water. Anhydrous magnesium sulfate was added to this organic phase, it was dried, filtered, activated carbon was added and stirred for a while, the activated carbon was removed by filtration, and the solvent was removed using a rotary evaporator. 0.136 mol (yield 66%) was obtained. It was confirmed by ¹ H-NMR that the target product (nitro compound) was obtained.
^1H NMR (500MHz, _CDCl3 ): δ 8.14 (2H), 7.37 (2H), 4.16 (2H), 3.43 (2H), 2.95 (4H), 2.19 ( 1H), 1.25 (3H)

2nd step: Add 30.0 g of the nitro compound obtained above, 300 g of THF, and 3.0 g of iron-doped platinum carbon to a 500 ml four-necked flask equipped with a nitrogen inlet tube and a stirrer, and carefully place the inside of the container under a hydrogen atmosphere. was substituted with , and the reaction was allowed to proceed at room temperature for 24 hours. The reaction was terminated when the raw materials disappeared, and the 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. Thereafter, it was filtered again, and the solvent was removed using a rotary evaporator, and then dried using a high vacuum pump to obtain 25.1 g (0.113 mol, yield 95%) of a pale yellow viscous substance, which was the target product (NG4APhA). It was confirmed by ¹ H-NMR that the target product was obtained.
^1H NMR (500MHz, _CDCl3 ): 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)

<Abbreviation>
The abbreviations used in the preparation of the liquid crystal aligning agent are as follows.
(Diisocyanate)
Me-DIDPA: N,N-bis(4-isocyanatophenyl)-N-methylamine

(diamine)
NG4ABA: Ethyl (4-aminobenzyl) glycinate NG4APhA: Ethyl (4-aminophenethyl) glycinate DADPA: 4,4'-diaminodiphenylamine Me-DADPA: N-methyl-4,4'-diaminodiphenylamine Me-DPPDA: N- Methyl-2,5-di-4-aminophenylpyrrole DA-2MG: 1,2-bis(4-aminophenoxy)ethane

ＤＡＤＰＡ、Ｍｅ－ＤＡＤＰＡ、Ｍｅ－ＤＰＰＤＡは公知の化合物であり、文献記載の手法にて合成したものを用いた。

DADPA, Me-DADPA, and Me-DPPDA are known compounds, and those synthesized by methods described in literature were used.

(Tetracarboxylic dianhydride)
CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride 13DMCBDA: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

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

Moreover, the conditions for measuring the molecular weight of polyimide are as follows.
Equipment: Room temperature gel permeation chromatography (GPC) equipment (SSC-7200) manufactured by Senshu Kagaku Co., Ltd.
Column: Shodex column (KD-803, KD-805)
Column temperature: 50℃
Eluent: N,N'-dimethylformamide (as additives, 30 mmol/L of lithium bromide hydrate (LiBr.H ₂ O), 30 mmol/L of phosphoric acid anhydrous crystals (o-phosphoric acid), THF is 10ml/L)
Flow rate: 1.0 ml/min Standard samples for creating a calibration curve: TSK standard polyethylene oxide manufactured by Tosoh Corporation (molecular weight approx. 9000,000, 150,000, 100,000, 30,000) and polyethylene glycol manufactured by Polymer Laboratory Co., Ltd. Molecular weight approximately 12,000, 4,000, 1,000)

<Synthesis of polyurea copolymer>
Example 1
Me-DIDPA/NG4ABA, DADPA
Measure out 4.22 g (15.92 mmol) of Me-DIDPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, add 29.9 g of NMP to dissolve it, add 1.49 g (7.16 mmol) of NG4ABA, and let it cool at room temperature. The mixture was reacted for 1 hour, and 1.59 g (7.96 mmol) of DADPA was further added, and the mixture was reacted for 10 hours at 40° C. in a nitrogen atmosphere. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 420 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polyurea copolymer (polymer diluted solution: P-1) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Example 2
Me-DIDPA/NG4ABA, Me-DADPA
Measure out 4.22 g (15.92 mmol) of Me-DIDPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, add 29.9 g of NMP to dissolve it, add 1.59 g (7.63 mmol) of NG4ABA, and let it cool at room temperature. The mixture was reacted for 1 hour, and 1.70 g (7.96 mmol) of Me-DADPA was further added, and the mixture was reacted for 10 hours at 40° C. in a nitrogen atmosphere. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 380 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polyurea copolymer (polymer diluted solution: P-2) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Example 3
Me-DIDPA/NG4APhA, Me-DADPA
Weigh out 4.22 g (15.92 mmol) of Me-DIDPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirring bar, add 30.5 g of NMP to dissolve it, add 1.70 g (7.63 mmol) of NG4APhA, and let the mixture cool to room temperature. The mixture was reacted for 1 hour, and 1.70 g (7.96 mmol) of Me-DADPA was further added, and the mixture was reacted for 24 hours at 40° C. in a nitrogen atmosphere. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 420 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polyurea copolymer (polymer diluted solution: P-3) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Example 4
Me-DIDPA/NG4ABA, Me-DPPDA
Weigh out 4.22 g (15.92 mmol) of Me-DIDPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, add 32.8 g of NMP to dissolve it, add 1.59 g (7.63 mmol) of NG4ABA, and let the mixture cool at room temperature. The mixture was reacted for 1 hour, and 2.09 g (7.96 mmol) of Me-DPPDA was further added, and the mixture was reacted for 24 hours at 23° C. in a nitrogen atmosphere. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 350 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polyurea copolymer (polymer diluted solution: P-4) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Comparative example 1
Me-DIDPA/Me-DADPA
Weighed 4.22 g (15.96 mmol) of Me-DIDPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, added 40.5 g of NMP and dissolved it, and added 3.15 g (14.78 mmol ) of Me-DADPA. was added and reacted at 40° C. for 24 hours under a nitrogen atmosphere. However, as the reaction progressed, stirring became impossible, and the diluted polymer solution (PRef-1) could not be prepared.

Comparative example 2
CBDA/DADPA
Weigh out 4.00 g (20.01 mmol) of DADPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, add 43.5 g of NMP and dissolve it, add 3.67 g (18.61 mmol) of CBDA, and place in a nitrogen atmosphere. The reaction was carried out at ℃ for 24 hours. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 520 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polymer (polymer diluted solution: PRef-2) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Comparative example 3
CBDA/Me-DADPA
Weigh out 4.00 g (18.75 mmol) of Me-DADPA into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirrer, add 42.04 g of NMP and dissolve it, add 3.42 g (17.44 mmol) of CBDA, and add nitrogen The reaction was carried out at an atmosphere of 23° C. for 24 hours. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 440 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polymer (polymer diluted solution: PRef-3) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

Comparative example 4
CBDA, 13DMCBDA/DA-2MG
Weigh out 4.00 g (16.38 mmol) of DA-2MG into a 50 ml two-necked flask equipped with a nitrogen inlet tube and a stirring bar, add 40.91 g of NMP and dissolve it, and add 1.84 g (8.19 mmol) of 13DMCBDA and 1.38 g of CBDA. (7.04 mmol) was added and reacted for 24 hours at 23° C. in a nitrogen atmosphere. As a result, a polymer solution having a concentration of 15% by mass and a viscosity of 470 mPas was obtained. 20.0 g of the above polymer solution was weighed into a 100 ml Erlenmeyer flask equipped with a stirrer, 15.0 g of NMP and 15.0 g of BCS were added, and the mixture was stirred at room temperature for 30 minutes. As a result, a polymer (polymer diluted solution: PRef-4) having a solid content of 6.0% by mass, NMP 64% by mass, and BCS 30% by mass was obtained.

<Measurement of transmittance (evaluation of film coloring)>
The polyurea copolymers (P-1 to P-4) obtained in the examples and the polymers (PRef-2 to PRef-3 ) obtained in the comparative examples were placed on a washed and dried quartz glass substrate (30 mm x 30mm, thickness 1.1mm) by spin coat printing so that the film thickness after firing is 100nm, and using a hot plate at 80°C for 1 minute and 220°C for 20 minutes. Fired. In this way, a sample for transmittance measurement (a membrane for transmittance measurement) was created. The transmittance was measured using UV-3600 manufactured by Shimadzu Corporation, and the coloration of the film was evaluated by evaluating the transmittance at 350 nm and 370 nm and the wavelength at the absorption edge of the UV spectrum. In addition, the odor was evaluated visually.

The evaluation results are shown in Table 1. The item of UV transmittance means that the larger the value, the smaller the degree of coloring of the film. Further, in the item of UV absorption edge, the larger the value, the lower the degree of coloring of the film.

In Examples 1 to 4 (P-1 to P-4), although the ratio of diphenylamines in the entire polymer was higher than that of Comparative Examples 2 to 3 (PRef-2 to PRef-3), the obtained membranes was colorless. In other words, it was confirmed that by using the polyurea copolymers of Examples 1 to 4, a film with higher transparency could be obtained compared to the case of using the polymers of Comparative Examples 2 to 3. There were also differences in UV transmittance and UV absorption edge between the films obtained using the polyurea copolymers of Examples 1 to 4 and the films obtained using the polymers of Comparative Examples 2 to 3. The difference in color was particularly noticeable when visually observed.

<Preparation of liquid crystal alignment agent>
Example 5
In a 50 ml Erlenmeyer flask equipped with a stirrer, 21.0 g of the polyurea copolymer (P-1) obtained in Example 1 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 were added. It was measured and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-1) having a mass ratio of polyurea copolymer ( P-1 ) and polymer (PRef-4) of 7:3 was obtained.

Example 6
In a 50 ml Erlenmeyer flask equipped with a stirrer, 21.0 g of the polyurea copolymer (P-2) obtained in Example 2 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 were added. It was measured and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-2) having a mass ratio of polyurea copolymer (P-2) and polymer (PRef-4) of 7:3 was obtained.

Example 7
In a 50 ml Erlenmeyer flask equipped with a stirrer, 21.0 g of the polyurea copolymer (P-3) obtained in Example 3 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 were added. It was measured and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-3) having a mass ratio of polyurea copolymer (P-3) and polymer (PRef-4) of 7:3 was obtained.

Example 8
In a 50 ml Erlenmeyer flask equipped with a stirrer, 21.0 g of the polyurea copolymer (P-4) obtained in Example 4 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 were added. It was measured and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-4) having a mass ratio of polyurea copolymer (P-4) and polymer (PRef-4) of 7:3 was obtained.

Comparative example 5
Weigh out 21.0 g of the polymer (PRef-2) obtained in Comparative Example 2 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 into a 50 ml Erlenmeyer flask equipped with a stirrer. , and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-5) having a mass ratio of polymer (PRef-2) and polymer (PRef-4) of 7:3 was obtained.

Comparative example 6
Weigh out 21.0 g of the polymer (PRef-3) obtained in Comparative Example 3 and 9.0 g of the polymer (PRef-4) obtained in Comparative Example 4 into a 50 ml Erlenmeyer flask equipped with a stirrer. , and stirred for 30 minutes. As a result, a liquid crystal aligning agent (AL-6) having a mass ratio of polymer (PRef-3) and polymer (PRef-4) of 7:3 was obtained.

Using the liquid crystal alignment agents (AL-1 to AL-4) of Examples 5 to 8 and the liquid crystal alignment agents (AL-5 to AL-6) of Comparative Examples 5 to 6, a liquid crystal alignment film was formed based on the following method. evaluated.

<Evaluation of whitening resistance and coatability (printability)>
One drop of each of the obtained liquid crystal alignment agents was placed on a well-cleaned Cr substrate, and the substrate was left at a room temperature of 25° C. and a humidity of 60%, and the time until it turned white was measured. Whitening resistance was evaluated based on the measured time.

After filtering the liquid crystal alignment agent through a 1.0 μm filter, a coating property test was performed by performing flexographic printing on a washed Cr plate using an alignment film printing machine (“Angstromer” manufactured by Nissha Printing Co., Ltd.). went.

About 1.0 ml of liquid crystal alignment agent was dropped onto the anilox roll, and after 10 idle runs, the printing press was stopped for 10 minutes and the printing plate was dried. Thereafter, printing was performed on one Cr substrate, and the printed substrate was left on a hot plate at 70° C. for 5 minutes to temporarily dry the coating film, and the state of the film was observed. The film thickness unevenness and the film thickness unevenness at the edge portion were mainly observed visually and with an optical microscope ("ECLIPSE ME600" manufactured by Nikon Corporation) at a magnification of 50 times.

<Evaluation of rubbing resistance>
After filtering the liquid crystal aligning agent with a 1.0 μm filter, a substrate with electrodes (a glass substrate with dimensions of 30 mm in width x 40 mm in height and a thickness of 1.1 mm.The electrodes are rectangular with a width of 10 mm x length of 40 mm, It was applied onto an ITO electrode (35 nm thick) by spin coat printing. After drying on a hot plate at 80°C for 5 minutes, baking was performed in an IR oven at 220°C for 20 minutes to form a coating film with a thickness of 100 nm. After rubbing this film with rayon cloth (YA-20R manufactured by Yoshikawa Kako) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm/sec, indentation length: 0.5 mm), the surface of the film was confocal Observation was made using a laser microscope. If no peeling of the film was observed, and if there were not many scrapes or scratches on the film, it was evaluated as "good", and if any defects were confirmed, it was evaluated as "poor".

<Voltage holding rate>
[Observation of liquid crystal orientation and fabrication of liquid crystal cell]
After filtering the liquid crystal aligning agent with a 1.0 μm filter, a substrate with electrodes (a glass substrate with dimensions of 30 mm in width x 40 mm in height and a thickness of 1.1 mm.The electrodes are rectangular with a width of 10 mm x length of 40 mm, It was applied onto an ITO electrode (35 nm thick) by spin coat printing. 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 with a thickness of 100 nm. This film was rubbed with rayon cloth (YA-20R manufactured by Yoshikawa Kako) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm/sec, pushing length: 0.4 mm), and then immersed in pure water for 1 minute. After washing by irradiating ultrasonic waves and removing water droplets by air blowing, the substrate was dried at 80° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film.

Prepare two substrates with the above liquid crystal alignment film, sprinkle 4 μm spacers on the surface of one of the liquid crystal alignment films, print a sealant on top of it, and rub the other substrate in the opposite direction. After pasting them together so that the film surfaces faced each other, the sealant was cured to create an empty cell. MLC-2041 (manufactured by Merck & Co., Ltd.) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell. Thereafter, after observing the liquid crystal orientation, 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 voltage holding rate measurement.

Using the liquid crystal cell for voltage retention measurement obtained in the above procedure, a voltage of 1V was applied for 60μs at a temperature of 60℃, the voltage after 166.7ms was measured, and how long the voltage could be maintained was measured. The voltage holding rate was calculated as the voltage holding rate. Note that a VHR-1 voltage holding rate measuring device manufactured by Toyo Technica Co., Ltd. was used to measure the voltage holding rate.

[Measurement of characteristics related to accumulation of RDC (residual voltage: voltage that remains even after voltage application is removed) and characteristics related to relaxation of accumulated charge]
The above liquid crystal cell for voltage holding rate measurement was installed between two polarizing plates arranged so that the polarization axes were perpendicular to each other, and the pixel electrode and the counter electrode were short-circuited to have the same potential. The LED backlight is irradiated from below the polarizing plate, and the angle of the liquid crystal cell is adjusted so that the brightness measured on the two polarizing plates (the brightness of the light transmitted through the LED backlight) is the minimum. did.

Next, while applying a rectangular wave with a frequency of 30 Hz to this liquid crystal cell, the VT characteristics (voltage-transmittance characteristics) at a temperature of 23°C were measured, and the AC voltage at which the relative transmittance was 23% was determined. Calculated. This alternating current voltage corresponds to a region where the luminance changes significantly with respect to voltage, and is therefore convenient for evaluating RDC.

Next, while applying an AC voltage with a relative transmittance of 23% and a rectangular wave with a frequency of 30 Hz, +3.0 V DC voltage was superimposed and driven for 1 hour, and the flicker level after 1 hour was determined. The amount of accumulated charge was estimated by measuring and converting it to the RDC accumulation level. After that, the DC voltage was turned off, and an AC voltage with a relative transmittance of 23% and only a rectangular wave with a frequency of 30 Hz was applied for 30 minutes, and the level of flicker that occurred at this time and the time until the flicker stopped occurring. The time (recovery time) was measured.

The faster the accumulated charge is relaxed, the shorter the recovery time is, that is, the better the RDC relaxation characteristics are. Note that the flicker intensity can be calculated by converting the brightness into a DC voltage using a photodiode and an AC-DC converter, and reading this with an oscilloscope. When flicker occurs, it is monitored as an alternating current voltage correlated to a 30 Hz rectangular wave, so the time when this alternating current voltage becomes direct current can be regarded as the relaxation time of RDC. The results of various evaluations are shown in Tables 2 and 3.

The polyurea copolymers (P-1 to P-4) obtained in Examples 1 to 4 and the polymers (PRef-2 to PRef-3) obtained in Comparative Examples 2 to 3 have a liquid crystal alignment property. Poor. Therefore, in order to evaluate the liquid crystal alignment properties, for convenience, the liquid crystal aligning agents (AL-1 to AL-4) of Examples 5 to 8 and comparative examples were blended with a polymer (PRef-4) as a high alignment component. 5 to 6 liquid crystal alignment agents (AL-5 to AL-6) were obtained. Therefore, in Examples 5 to 8, it is also possible to obtain a liquid crystal aligning agent without blending the polymer (PRef-4), and even in this case, the liquid crystal aligning agent may be as shown in Table 3. It is presumed to have excellent various properties.

The liquid crystal alignment agents (AL-1 to AL-4) of Examples 5 to 8 have good compatibility with polyamic acid, although their structures are significantly different from that of polyamic acid, and accordingly, the coating properties by flexographic printing ( Printability) was also good. Furthermore, it was confirmed that the liquid crystal aligning films obtained using these liquid crystal aligning agents (AL-1 to AL-4) were less prone to whitening and aggregation.

It is known that polyamic acids are in an equilibrium state with diamines and acid dianhydrides, and that heating causes partial decomposition of the polyamic acids. In particular, when a material exhibiting rapid RDC relaxation is used, The voltage holding ratio (VHR) of the resulting liquid crystal alignment film tends to deteriorate. However, the polyurea copolymer, which is one embodiment of the present invention, does not undergo decomposition due to heating, so it is thought that it exhibited a high VHR.

Furthermore, although the liquid crystal alignment films obtained using the polyurea copolymers obtained in Examples 1 to 4 are less colored than the comparative examples, they are superior to the comparative examples in terms of suppressing RDC accumulation. It showed similar or better properties. In the case of unreliable materials, ionic impurities may accumulate at the interface between the liquid crystal and the alignment film, forming a state similar to an electric double layer. May be confirmed. However, this was not observed in the liquid crystal aligning films obtained using the liquid crystal aligning agents of Examples 5 to 8. In addition, even if any of the liquid crystal alignment agents of Examples 5 to 8 was used, a liquid crystal alignment film and a liquid crystal display element could be suitably obtained.

The liquid crystal display element produced using the liquid crystal aligning agent of the present invention has good color reproducibility and can be made into a highly reliable liquid crystal display device, such as a TN liquid crystal display element, an STN liquid crystal display element, a TFT liquid crystal display element, It can be suitably used in display elements of various systems, such as VA liquid crystal display elements, IPS liquid crystal display elements, and OCB liquid crystal display elements.

Claims (6)

A polyurea copolymer having a structure represented by the following formula (1).

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, which may be branched, and R ₂ is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, or the following formula (1-1) Indicates an organic group represented by Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 2 carbon atoms. X represents a divalent organic group represented by the following formula (S), Y represents a divalent organic group represented by the following formula (S), or a divalent organic group represented by the following formula (Q-1) represents an organic group.

In the formula, the black dots mean bonding sites to the nitrogen atom, and R ₁ , Ra and Rb have the same meanings as R ₁ , Ra and Rb above.

In the formula, Q ¹ and Q ² represent one selected from formula (Q1-1), formula (Q1-2), and a single bond. However, at least one of Q ¹ and Q ² represents one type selected from (Q1-1) and (Q1-2). q1 and q2 each independently represent 0 or 1, and when q1 and q2 are both 0, Q ¹ is one selected from (Q1-1) and (Q1-2), and L ¹ and L ² are Indicates a hydrogen atom. However, when Q ¹ is the formula (Q1-1), L ¹ and L ² may be combined to form a single bond. Black dots indicate bonding points to nitrogen atoms.

In the formula, R ₅ represents a hydrogen atom, a t-butoxycarbonyl group, or an alkyl group having 1 to 6 carbon atoms. When R ₅ represents an alkyl group having 1 to 6 carbon atoms, it may be branched, form a ring, or have an unsaturated bond. E represents -NH-, -NMe-, -S-, or -O-, and F and G each independently represent CH or a nitrogen atom.

In the formula, A represents a divalent organic group such as an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and B and C are each independently a single bond or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. shows. Black dots indicate bonding points to nitrogen atoms. The polyurea copolymer according to claim 1, wherein the X represents a divalent organic group represented by the following formula.

In the formula, black dots mean bonding sites to nitrogen atoms. The polyurea copolymer according to claim 1 or 2 , wherein Y is a divalent organic group represented by the following formula (Q-2).

In the formula, D represents a single bond or a hydrocarbon group having 1 to 5 carbon atoms. Black dots indicate bonding points to nitrogen atoms. A liquid crystal aligning agent using the polyurea copolymer according to any one of claims 1 to 3 . A liquid crystal aligning film obtained from the liquid crystal aligning agent according to claim 4 . A liquid crystal display element using the liquid crystal alignment film according to claim 5 .