JP7299556B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal aligning agent used in the production of liquid crystal display elements, a liquid crystal aligning film obtained from this liquid crystal aligning agent, and a liquid crystal display element using this liquid crystal aligning film.

Liquid crystal display elements are known as lightweight, thin and low power consumption display devices. In recent years, high-definition liquid crystal display elements for mobile phones and tablet terminals, which have rapidly expanded their market share, have made remarkable progress to the extent that high display quality is required.

A liquid crystal display element is constructed by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes. In the liquid crystal display device, an organic film made of an organic material is used as a liquid crystal alignment film so that the liquid crystal is in a desired alignment state between the substrates. That is, the liquid crystal alignment film is a constituent member of the liquid crystal display element, is formed on the surfaces of the substrates that sandwich the liquid crystal and is in contact with the liquid crystal, and plays the role of orienting the liquid crystal in a certain direction between the substrates.

In recent years, liquid crystal display elements have been used for mobile applications such as smart phones and mobile phones. In these applications, in order to secure as many display surfaces as possible, it is necessary to make the width of the sealant used for bonding the substrates of the liquid crystal display element narrower than before. Furthermore, for the reasons described above, it is also required to position the sealant at a position in contact with the edge of the liquid crystal alignment film where the adhesiveness to the sealant is weak, or at the upper portion of the liquid crystal alignment film. In such a case, especially when used under high-temperature and high-humidity conditions, water is likely to enter from between the sealant and the liquid crystal alignment film, resulting in display unevenness near the frame of the liquid crystal display element.

In order to solve this problem, a liquid crystal aligning agent using an additive having a specific structure has been proposed (see Patent Document 1).

WO2015/072554

However, in recent years, there has been a demand for further improvement in adhesion between the liquid crystal alignment film and the sealant.

Of these, in the property improvement from the sealant, it is known that it is difficult to achieve both the adhesion property between the sealant and the liquid crystal alignment film and the moisture permeation prevention property of the sealant. There is a demand for improvement in characteristics from

Accordingly, an object of the present invention is to provide a liquid crystal aligning agent capable of enhancing adhesion between a sealing agent and a liquid crystal aligning film and suppressing occurrence of display unevenness in the vicinity of the frame of a liquid crystal display element under high-temperature and high-humidity conditions. and

The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, developed a liquid crystal alignment film containing a polymer having a specific aromatic heterocycle, a primary amino group and a secondary amino group in its structure. It came to complete this invention by using.

A first aspect of the present invention for achieving the above object is a liquid crystal alignment film characterized by containing a polymer having an aromatic heterocycle and a primary amino group and a secondary amino group in its structure.

A second aspect of the present invention for achieving the above object is a film made of a fired product, wherein the skeleton of the aromatic heterocycle and the primary amino group and the secondary amino group are formed in a structure formed by firing The liquid crystal alignment film of the first aspect, characterized by containing

A third aspect of the present invention for achieving the above object is the liquid crystal according to the first aspect or the second aspect, wherein the aromatic heterocycle is a pyridine skeleton, a benzimidazole skeleton, or an imidazole skeleton. It is in the alignment film.

A fourth aspect of the present invention for achieving the above object is the liquid crystal alignment film according to the second aspect, characterized in that the baked product is produced at a baking temperature of 100°C to 300°C.

A fifth aspect of the present invention for achieving the above object is a liquid crystal display device comprising the liquid crystal alignment film according to any one of the first to fourth aspects.

A sixth aspect of the present invention for achieving the above object is a liquid crystal aligning agent for obtaining a liquid crystal aligning film according to any one of the first to fourth aspects.

A seventh aspect of the present invention for achieving the above object is a diamine component containing at least one diamine selected from the following component (A) and the following component (B) and a diamine containing a skeleton of the following component (C) and at least one polymer selected from polyamic acid which is a reaction product with tetracarboxylic dianhydride and polyimide which is an imidized product thereof. .
Component (A): a diamine having at least one structure selected from the following formulas (1-1) and (1-2)

（式中、Ｄは２価の炭素数１～２０の飽和炭化水素基、不飽和炭化水素基、芳香族炭化水素基または複素環を表し、Ｄは種々の置換基を有していてもよく、Ｅは単結合、または、２価の炭素数１～２０の飽和炭化水素基、不飽和炭化水素基、芳香族炭化水素基もしくは複素環であり、Ｆは単結合またはエーテル結合（－Ｏ－）、エステル結合（－ＯＣＯ－、－ＣＯＯ－）を表し、ｍは、１または０であり、Ｒは熱脱離基を表し、＊は、他の原子との結合を表す。）
（Ｂ）成分：下記式（２）の構造を有するジアミン

(In the formula, D represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and D may have various substituents. , E is a single bond, or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, F is a single bond or an ether bond (-O- ), represents an ester bond (-OCO-, -COO-), m is 1 or 0, R represents a thermally leaving group, * represents a bond with another atom.)
(B) component: diamine having a structure of the following formula (2)

（式中、Ｘ_１は－Ｏ－、－ＮＱ^１－、－ＣＯＮＱ^１－、－ＮＱ^１ＣＯ－、－ＣＨ_２Ｏ－、及び－ＯＣＯ－からなる群より選ばれる少なくとも１種の２価の有機基であり、Ｑ^１は水素原子又は炭素数１から３のアルキル基であり、Ｘ_２は単結合、又は炭素数１から２０の脂肪族炭化水素基、非芳香族環式炭化水素基、及び芳香族炭化水素基からなる群より選ばれる少なくとも１種の２価の有機基であり、Ｘ_３は単結合、又は－Ｏ－、－ＮＱ^２－、－ＣＯＮＱ^２－、－ＮＱ^２ＣＯ－、－ＣＯＯ－、－ＯＣＯ－、及び－Ｏ（ＣＨ_２）_ｍ－（ｍは１から５の整数である）からなる群より選ばれる少なくとも１種の２価の有機基であり、Ｑ^２は水素原子又は炭素数１から３のアルキル基であり、Ｘ_４は芳香族複素環であり、＊は、他の原子との結合を表す。）
（Ｃ）成分：下記式（ａ）及び下記式（ｂ）から選ばれる少なくとも１種の構造を有するジアミン

(Wherein, X ₁ is at least one divalent selected from the group consisting of -O-, -NQ ¹ -, -CONQ ¹ -, -NQ ¹ CO-, -CH ₂ O-, and -OCO- an organic group, Q ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, X ₂ is a single bond, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a non-aromatic cyclic hydrocarbon group, and at least one divalent organic group selected from the group consisting of aromatic hydrocarbon groups, X ₃ is a single bond, or -O-, -NQ ² -, -CONQ ² -, -NQ ² CO- , —COO—, —OCO—, and —O(CH ₂ ) _m — (m is an integer of 1 to 5), wherein Q ² is at least one divalent organic group selected from the group consisting of A hydrogen atom or an alkyl group having 1 to 3 carbon atoms, _X4 is an aromatic heterocycle, and * represents a bond with another atom.)
Component (C): a diamine having at least one structure selected from the following formulas (a) and (b)

（式中、Ｘ^１は酸素原子又は硫黄原子であり、Ａ^１～Ａ^３はそれぞれ独立に水素原子又は炭素数１～３の炭化水素基であり、炭素数の合計は１～９である。また、＊は、他の原子との結合を表す。）

(In the formula, X ¹ is an oxygen atom or a sulfur atom, A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9. Moreover, * represents a bond with another atom.)

By using the liquid crystal aligning agent of the present invention, the adhesiveness between the sealing agent and the liquid crystal alignment film can be improved, and the occurrence of display unevenness near the frame of the liquid crystal display element can be suppressed under high temperature and high humidity conditions. can be obtained. Therefore, the liquid crystal display element having the liquid crystal alignment film obtained by this method can solve the display unevenness near the frame by increasing the adhesiveness between the sealing agent and the liquid crystal alignment film, and is suitable for large-screen, high-definition liquid crystal displays. can.

Each component of the liquid crystal alignment film of the present invention will be described in detail below.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention contains an aromatic heterocycle and a polymer having a primary amino group and a secondary amino group in its structure.

The liquid crystal alignment film of the present invention is formed by coating a liquid crystal alignment agent on a substrate, baking it, and forming a coating of the polymer contained in the liquid crystal alignment agent (hereinafter also referred to as coating), followed by rubbing treatment and light irradiation. It is manufactured by performing an orientation treatment such as. In the case of vertical alignment use, it can be used as a liquid crystal alignment film without alignment treatment.

The substrate used in this case is not particularly limited as long as it is highly transparent, and in addition to a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate can also be used. From the viewpoint of simplification of the process, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed. In addition, in a reflective liquid crystal display element, an opaque substrate such as a silicon wafer can be used if only one substrate is used. In this case, a light-reflecting material such as aluminum can be used as the electrode.

The method of applying the liquid crystal aligning agent is not particularly limited, but industrially, methods such as screen printing, offset printing, flexographic printing, and inkjet are common. Other coating methods include dip, roll coater, slit coater, spinner, and the like, and these may be used depending on the purpose.

After coating the liquid crystal aligning agent on the substrate, the solvent is evaporated at 100° C. to 300° C., preferably 100° C. to 250° C., more preferably 150° C. to 250° C. by heating means such as a hot plate to form a polymer film. (This step is also referred to as a firing step hereinafter).

In the baking step, the thermally-leaving groups protecting the amino groups in the polymer are desorbed by heat, generating highly reactive primary and secondary amino groups, some of which are polymerized. By performing a cyclization reaction with other sites during coalescence, an aromatic heterocycle is generated, and as a result, the liquid crystal alignment film of the present invention can be obtained. It is preferable from the viewpoint of sex.

The structure of the thermally-leaving group-bonded amino group, which is preferably contained in the polymer of the present invention, is represented, for example, as follows.

In the above formula (a), X ¹ is an oxygen atom or a sulfur atom, A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9 is. In the above formulas (a) and (b), * represents a bond with another atom.

Examples of structures capable of generating an aromatic heterocycle by cyclization with a primary amino group include the following structures.

In the formula, D represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and D may have various substituents. In addition, E is a single bond, or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, F is a single bond or an ether bond (-O -) represents an ester bond (-OCO-, -COO-). m is 1 or 0; R is a structure represented by formula (a) above.

The thickness of the coating after the baking step is preferably 5 nm to 300 nm, more preferably 5 nm to 300 nm, because if it is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. 10 nm to 100 nm. When the liquid crystal is horizontally aligned or tilted, the film after baking is subjected to an alignment treatment by a known method such as rubbing or polarized ultraviolet irradiation.

<Aromatic heterocycle>
Examples of the aromatic heterocycle contained in the polymer in the liquid crystal alignment film of the present invention include pyrrole ring, furan ring, thiophene ring, imidazole ring, pyrazole ring, oxazole ring, isoxazole ring, and thiazole ring. , 5-membered aromatic heterocycles such as isothiazole ring; 6-membered aromatic heterocycles such as pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring; quinoline, isoquinoline, coumarin, indole, benzimidazole, benzofuran and polycyclic aromatic heterocyclic compounds such as

Among these, pyridine ring, imidazole ring, and benzimidazole ring are preferred, and imidazole ring and benzimidazole ring are particularly preferred, from the viewpoint of exhibiting the effects of the present invention more remarkably.

The aromatic heterocyclic ring exhibits the effects of the present invention even if it is already present in the polymer contained in the liquid crystal aligning agent. is preferably formed. In addition, the aromatic heterocycle which already exists in the polymer contained in a liquid crystal aligning agent, and the aromatic heterocycle formed at the time of baking may coexist.

<Polymer>
The liquid crystal aligning agent of the present invention and the polymer contained in the liquid crystal alignment film obtained using the same are not particularly limited as long as they have an aromatic heterocycle and a primary amino group and a secondary amino group in the structure. However, from the viewpoint of the characteristics and reliability of the resulting liquid crystal display device, at least one polymer selected from polyimide precursors, which are reaction products of diamine components and tetracarboxylic derivative components, and polyimides, which are imidized products thereof. Preferably.

The polyimide precursor referred to here refers to polyamic acid or polyamic acid ester.

<Diamine>
The polymer contained in the liquid crystal aligning agent of the present invention and the liquid crystal alignment film obtained using the same is preferably at least one polymer selected from polyimide precursors and imidized polyimides thereof. , Among the diamine components used for its production are a diamine having a structure that produces an aromatic heterocycle (hereinafter also referred to as specific diamine 1) and a diamine having an aromatic heterocycle in its structure (hereinafter also referred to as specific diamine 2) ) and a diamine having a structure that produces a primary amino group or a secondary amino group (hereinafter also referred to as specific diamine 3).

Each diamine is described in detail below.

<Specific diamine 1>
Specific diamine 1 has a structure selected from the following formulas (1-1) and (1-2).

In the above formula (1-1), D represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and D has various substituents. You may have Further, in the above formula (1-2), E is a single bond, or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and F represents a single bond, an ether bond (--O--) or an ester bond (--OCO--, --COO--). In formula (1-1) above, m is 1 or 0. In the above formulas (1-1) and (1-2), R represents a thermally leaving group.

* in the above formulas (1-1) and (1-2) represents a bond with another atom. When binding to an amino group, the substitution position of the amino group is not particularly limited, but from the viewpoint of the difficulty of synthesis and the availability of reagents, the meta or para position is preferable with respect to the amide bond, and the viewpoint of liquid crystal orientation. The para position is particularly preferred. Also in aminobenzene having no amino group protected by a thermally leaving group, the meta or para position is preferred when similarly based on the amide bond, and the meta position is preferred from the viewpoint of solubility. From the viewpoint of liquid crystal orientation, the para position is preferred. In addition, the hydrogen of aminobenzene not having —NHR may be substituted with an organic group or a halogen atom such as fluorine.

Further, * in the above formula (1-1) may be bonded to the same structure of the above formula (1-1) or the structure of the above formula (1-2), via another atom, the above It may be bonded to the structure of formula (1-1) or the structure of formula (1-2) above.

D in the above formula (1-1) and E in the above formula (1-2) are the same as defined above, but the details are not particularly limited, and the dicarboxylic acid or tetracarboxylic acid used as a raw material Various structures can be selected depending on the structure of the anhydride. D is preferably a divalent hydrocarbon group or the like from the viewpoint of solubility, and preferred examples thereof include a straight-chain alkylene group and a cyclic alkylene group, and the hydrocarbon group may have an unsaturated bond. . From the viewpoint of liquid crystal orientation and electrical properties, a divalent aromatic hydrocarbon group, a heterocyclic ring, and the like are preferable. From the viewpoint of liquid crystal orientation, it is preferable that D does not have a substituent, but from the viewpoint of solubility, it is preferable that a hydrogen atom is substituted with a carboxylic acid group, a fluorine atom, or the like.

<Specific diamine 2>
Specific diamine 2 has the structure of the following formula (2).

In the above formula (2), X ₁ is at least one selected from the group consisting of -O-, -NQ ¹ -, -CONQ ¹ -, -NQ ¹ CO-, -CH ₂ O-, and -OCO- a divalent organic group, Q ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ₂ is a single bond, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, or a non-aromatic cyclic hydrocarbon group; at least one divalent organic group selected from the group consisting of a hydrogen group and an aromatic hydrocarbon group, wherein X ₃ is a single bond or -O-, -NQ ² -, -CONQ ² -, -NQ ² is at least one divalent organic group selected from the group consisting of CO—, —COO—, —OCO—, and —O(CH ₂ ) _m — (m is an integer of 1 to 5); ^Q2 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and _X4 is an aromatic heterocycle.

* represents a bond with another atom. When binding to an amino group, the binding positions of the two amino groups (--NH ₂ ) are not limited. Specifically, the 2,3-positions, 2,4-positions, 2,5-positions, 2,6-positions, 3,4-positions on the benzene ring with respect to the side chain bonding groups (X ₁ ) position, 3,5 positions. Among these, considering the reactivity in synthesizing the polyamic acid and the ease in synthesizing the diamine compound, the bonding positions of the two amino groups are 2,4, 2,5, The 3,5 position is particularly preferred.

In addition, * may be bonded to the same structure of formula (2), or may be bonded to the structure of formula (2) via another atom.

X ₁ is at least one divalent organic group selected from the group consisting of -O-, -NQ ¹ -, -CONQ ¹ -, -NQ ¹ CO-, -CH ₂ O- and -OCO- . Among them, -O-, -NQ ¹ -, -CONQ ¹ - and -NQ ¹ CO- are preferred. Q ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group.

_X2 is a single bond, or at least one divalent organic group selected from the group consisting of aliphatic hydrocarbon groups having 1 to 20 carbon atoms, non-aromatic cyclic hydrocarbon groups, and aromatic hydrocarbon groups; be.

The aliphatic hydrocarbon group having 1 to 20 carbon atoms may be linear or branched. Moreover, you may have an unsaturated bond. Aliphatic hydrocarbon groups having 1 to 10 carbon atoms are preferred.

X ₃ is a single bond, or -O-, -NQ ² -, -CONQ ² -, -NQ ² CO-, -COO-, -OCO-, and -O(CH ₂ ) _m - (m is 1 to 5 is an integer of at least one divalent organic group selected from the group consisting of a single bond, -O-, -CONQ ² -, -NQ ² CO-, -COO-, -OCO -, -O(CH ₂ ) _m - (m is an integer from 1 to 5). Most preferably, it is a single bond, -OCO- or -OCH ₂ -. Q ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group.

_X4 is an aromatic heterocycle. Its exemplary and preferred structures are the same as those described above.

Particularly preferred combinations of X ₁ , X ₂ , X ₃ , X ₄ and n are as shown in Tables 1 to 3 below. Note that Q ¹ and Q ² have the same meanings as defined above.

<Specific diamine 3>
Specific diamine 3 is a diamine having a structure that produces a primary amino group or a secondary amino group, and has an amino group structure protected by a thermally leaving group in its structure. Although such a structure is not particularly limited, it preferably contains at least one structure selected from the following structures from the viewpoint of ease of thermal desorption.

In the above formula (a), X ¹ is an oxygen atom or a sulfur atom, A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9 is. In addition, in the above formulas (a) and (b), * represents a bond with another atom.

In formula (a) above, X ¹ is an oxygen atom or a sulfur atom, preferably an oxygen atom. A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, preferably 1 carbon atom. The total number of carbon atoms is 1-9, preferably 3-6. In addition, in the above formulas (a) and (b), * represents a bond with another atom.

Examples of the diamine having in its structure at least one structure selected from the above formula (a) and the above formula (b) include diamines having the following structures. "Boc" in the formula is a tert-butoxycarbonyl group.

<Diamine having an amino group not involved in polymerization>
In the production of the liquid crystal aligning agent for obtaining the liquid crystal alignment film of the present invention, a diamine having a structure that produces a primary amino group or a secondary amino group, that is, a structure of an amino group protected by a thermally leaving group. Diamines having amino groups that are unprotected and that do not participate in polymerization may be used, although diamines containing amino groups are used. Such diamines are exemplified below.

<Other diamines>
In producing a polyimide precursor that is preferably used as a polymer contained in the liquid crystal aligning agent of the present invention, a diamine other than the specific diamine (hereinafter, also referred to as other diamine) is contained, as long as the effect of the present invention is achieved. You can Such diamines are represented by the following general formula (3).

In the above formula (3), Y is a divalent organic group derived from diamine, and its structure is not particularly limited. Specific examples of the structure of Y include the following formulas (Y-1) to (Y-99).

In the above formula (Y-90), m and n are each an integer of 1 to 11, m+n is an integer of 2 to 12, and in the above formula (Y-95), h is an integer of 1 to 3. , j is an integer of 0 to 3 in the above formulas (Y-92) and (Y-98).

<Tetracarboxylic dianhydride>
The tetracarboxylic dianhydride used in producing the polyimide precursor preferably used as the polymer contained in the liquid crystal aligning agent of the present invention is represented by the following formula (4).

In the above formula (4), X is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. Two or more types of X may be mixed in the polyimide precursor. Specific examples of X include structures of formulas (X-1) to (X-44) below.

Moreover, when producing a polyamic acid ester, it can be produced using dicarboxylic acid diesters corresponding to various structures of the tetracarboxylic dianhydrides listed here.

R ₁ to R ₄ in the above formula (X-1) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group, or a phenyl is the base. If R ₁ to R ₄ have a bulky structure, the liquid crystal orientation may be lowered, so a hydrogen atom, a methyl group, or an ethyl group is more preferred, and a hydrogen atom or a methyl group is particularly preferred.

In the above formula (4), X preferably contains a structure selected from the above formulas (X-1) to (X-14) from the viewpoint of availability of the monomer.

Since the reliability of the obtained liquid crystal alignment film can be further improved, the structure of X is an aliphatic group such as the above formula (X-1) to the above formula (X-7) and the above formula (X-10) A structure consisting of only is preferable, and a structure represented by the above formula (X-1) is more preferable. Furthermore, the structure of X is more preferably the following formula (X1-1) or the following formula (X1-2) in order to exhibit good liquid crystal orientation.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention has the form of a solution in which the polyimide precursor or its imidized polymer (hereinafter referred to as a polymer having a specific structure) is dissolved in an organic solvent. The weight-average molecular weight of the polymer having the specific structure is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably 8,000 to 100,000. Also, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, still more preferably 4,000 to 50,000.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed by setting the thickness of the coating film to be formed. % or more, and preferably 10% by weight or less from the viewpoint of storage stability of the solution. A particularly preferred polymer concentration is 2 to 8% by weight.

The organic solvent contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as it uniformly dissolves the polymer having the specific structure. Specific examples include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethylsulfoxide, dimethylsulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide and the like. These may be used singly or in combination of two or more. Moreover, even a solvent that cannot uniformly dissolve the polymer by itself may be mixed with the above organic solvent as long as the polymer is not precipitated. Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

In addition, the organic solvent contained in the liquid crystal aligning agent is a mixed solvent in which a solvent that improves the coating properties and the surface smoothness of the coating film when applying the liquid crystal aligning agent in addition to the above solvents is used. is common, and such a mixed solvent is suitably used also in the liquid crystal aligning agent of this invention. Specific examples of the organic solvent used in combination are listed below, but are not limited to these examples.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol , 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2,6- dimethyl-4-heptanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2, 3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene Glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2- Pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutylacetate, 1-methylpentylacetate tart, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl Ether, ethylene glycol monohexyl ether, 2-(hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(butoxyethoxy)propanol, propylene glycol monomethyl Ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Butyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, tri Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate , ethyl 3-ethoxypropionate, methylethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, lactic acid Examples include methyl ester, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and solvents represented by the following formulas [D-1] to [D-3].

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

Preferred combinations of solvents include N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, and N-ethyl-2-pyrrolidone. and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether. be able to. The kind and content of such a solvent are appropriately selected according to the liquid crystal aligning agent coating device, coating conditions, coating environment, and the like.

In addition to the above, the liquid crystal aligning agent of the present invention may include a polymer other than the polymer described in the present invention, and an electric material such as the dielectric constant and conductivity of the liquid crystal aligning film, as long as the effects of the present invention are not impaired. Dielectric or conductive substance for the purpose of changing characteristics, silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, crosslinkability for the purpose of increasing the hardness and denseness of the film when it is made into a liquid crystal alignment film A compound, and furthermore, an imidization accelerator or the like for the purpose of efficiently advancing the imidization by heating of the polyimide precursor when baking the coating film may be added.

In addition, additives such as silane coupling agents may be added to the liquid crystal aligning agent of the present invention in order to improve the adhesion of the coating film to the substrate, and other resin components may be added. .

Compounds that improve the adhesion between the liquid crystal alignment film and the substrate include functional silane-containing compounds and epoxy group-containing compounds. glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2- aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl- 3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 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-aminopropyltrimethoxysilane, 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-tetraglycidyl-2,4-hexanediol, N,N,N',N',-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane or N, N,N',N',-tetraglycidyl-4,4'-diaminodiphenylmethane and the like.

Moreover, in order to raise the mechanical strength of a film|membrane, you may add the following additives to the liquid crystal aligning agent of this invention.

These additives are preferably 0.1 to 30 parts by weight per 100 parts by weight of the polymer component contained in the liquid crystal aligning agent. If the amount is less than 0.1 parts by mass, the effect cannot be expected, and if the amount exceeds 30 parts by mass, the orientation of the liquid crystal is deteriorated.

<Liquid crystal display element>
The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the method described above, performing an alignment treatment such as rubbing, and then using a known method to obtain a liquid crystal display element. be.

The manufacturing method of the liquid crystal cell of the liquid crystal display element is not particularly limited, but to give an example, a pair of substrates on which the liquid crystal alignment film is formed is preferably 1 μm to 30 μm, more preferably 1 μm to 30 μm, with the liquid crystal alignment film surface facing inside. is generally installed by sandwiching a spacer of 2 μm to 10 μm, fixing the periphery with a sealing agent, and injecting liquid crystal for sealing. The method of encapsulating the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which liquid crystal is injected after reducing the pressure in the liquid crystal cell produced, and a dropping method in which sealing is performed after dropping liquid crystal. Since the liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention as described above has excellent properties, it can be It can be used as a liquid crystal alignment film for ferroelectric and antiferroelectric liquid crystal display elements.

EXAMPLES The present invention will be specifically described below with reference to examples, etc., but the present invention is not limited to these examples. Abbreviations of compounds and solvents are as follows.
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve DA-1: the following structural formula (DA-1)
DA-2: the following structural formula (DA-2)
DA-3: the following structural formula (DA-3)
DA-4: the following structural formula (DA-4)
DA-5: the following structural formula (DA-5)
DA-6: the following structural formula (DA-6)
DA-7: the following structural formula (DA-7)
DA-8: the following structural formula (DA-8)
DA-9: the following structural formula (DA-9)
DA-10: the following structural formula (DA-10)
CA-1: the following structural formula (CA-1)
CA-2: the following structural formula (CA-2)
CA-3: the following structural formula (CA-3)
CA-4: the following structural formula (CA-4)

<Viscosity>
In the synthesis examples, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample amount of 1.1 mL, a cone rotor TE-1 (1 ° 34', R24), and a temperature of 25. Measured in °C.

<Measurement of imidization rate of polyimide>
The imidization rate of polyimide in Synthesis Examples was measured as follows. 30 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) Mixture) (0.53 ml) was added and sonicated to completely dissolve. This solution was subjected to proton NMR at 500 MHz using an NMR spectrometer (JNW-ECA500) (manufactured by JEOL Datum Co., Ltd.). For the imidization rate, a proton derived from a structure that does not change before and after imidization is determined as a reference proton. It was obtained by the following formula using the integrated value.

Imidation rate (%) = (1-α x/y) x 100
In the above formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidization rate is 0%). is the number ratio of reference protons to

(Example 1)
86.0 g (352 mmol) of DA-1, 53.4 g (95.9 mmol) of DA-2, and 76.5 g (191 mmol) of DA-3 in a 1 L four-necked flask equipped with a stirring device and a nitrogen inlet tube. After weighing, 1580 g of NMP was added and dissolved by stirring while supplying nitrogen. While stirring this diamine solution under water cooling, 93.2 g (416 mmol) of CA-1 was added, 168 g of NMP was further added, and the mixture was stirred at 40° C. for 3 hours under a nitrogen atmosphere. Further, 28.2 g (143 mmol) of CA-2 was added, 160 g of NMP was added, and the mixture was stirred at 23° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution (PAA-1). The viscosity of this polyamic acid solution at a temperature of 25° C. was 200 mPa·s.

30.7 g of this polyamic acid solution (PAA-1) was placed in a 200 mL Erlenmeyer flask containing a stirrer, 9.07 g of NMP, 26.2 g of GBL, and 3-glycidoxypropyltriethoxysilane. 3.93 g of NMP solution containing 1% by mass and 17.4 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyamic acid solution (A-1).

(Example 2)
800 g of the polyamic acid solution (PAA-1) obtained in Example 1 was placed in a 3 L Erlenmeyer flask equipped with a stir bar, 700 g of NMP, 69.7 g of acetic anhydride, and 18.0 g of pyridine were added, After stirring at room temperature for 30 minutes, the mixture was reacted at 55°C for 3 hours. This reaction solution was poured into 5600 g of methanol, and the obtained precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at a temperature of 60° C. to obtain polyimide powder. The imidization rate of this polyimide powder was 75%.

20.4 g of this polyimide powder was placed in a 300 mL Erlenmeyer flask equipped with a stirrer, 115 g of NMP was added, and the mixture was dissolved by stirring at 50° C. for 20 hours. Furthermore, 16.3 g of this solution was placed in a 100 mL Erlenmeyer flask containing a stirrer, and an NMP solution containing 5.49 g of NMP, 14.3 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was prepared. 2.15 g and 9.56 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyimide solution (A-2).

(Synthesis example 1)
2.20 g (9.00 mmol) of DA-1, 2.04 g (5.97 mmol) of DA-4, 1.62 g of DA-5 ( 15.0 mmol) was weighed, 59.3 g of NMP was added, and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 6.32 g (28.1 mmol) of CA-1 was added, 30.0 g of NMP was further added, and the polyamic acid solution ( PAA-2) was obtained. The viscosity of this polyamic acid solution at a temperature of 25° C. was 220 mPa·s.

21.1 g of this polyamic acid solution (PAA-2) was placed in a 200 mL Erlenmeyer flask containing a stirrer, 2.20 g of NMP, 15.3 g of GBL, and 3-glycidoxypropyltriethoxysilane. 2.30 g of NMP solution containing 1% by mass and 10.2 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyamic acid solution (B-1).

(Synthesis example 2)
90.0 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 1 was placed in a 500 mL Erlenmeyer flask containing a stirrer, 45.0 g of NMP, 8.14 g of acetic anhydride, and 2 g of pyridine. .10 g was added, stirred at room temperature for 30 minutes, and then reacted at 55° C. for 3 hours. This reaction solution was poured into 600 g of methanol, and the obtained precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at a temperature of 60° C. to obtain polyimide powder. The imidization rate of this polyimide powder was 67%.

5.50 g of this polyimide powder was placed in a 300 mL Erlenmeyer flask containing a stirrer, 40.3 g of NMP was added, and the mixture was stirred at 50° C. for 20 hours to dissolve. Furthermore, 25.0 g of this solution was placed in a 200 mL Erlenmeyer flask containing a stirrer, and an NMP solution containing 5.30 g of NMP, 20.0 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was prepared. 3.00 g and 13.3 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyimide solution (B-2).

(Synthesis Example 3)
In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 0.540 g (4.99 mmol) of DA-5, 2.12 g (8.75 mmol) of DA-6, and 0.826 g of DA-7 ( 2.50 mmol), 3.80 g (8.75 mmol) of DA-8 was weighed, 41.3 g of NMP was added, and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 3.12 g (12.4 mmol) of CA-3 was added, 17.8 g of NMP was further added, and the mixture was stirred at 60° C. for 3 hours under a nitrogen atmosphere. Further, 2.42 g (12.3 mmol) of CA-2 was added, and 14.1 g of NMP was added, and the mixture was stirred at 40° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25° C. was 115 mPa·s.

20.6 g of this polyamic acid solution was placed in a 200 mL Erlenmeyer flask containing a stirrer, and NMP containing 10.6 g of NMP, 20.6 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was added. 3.09 g of the solution and 13.7 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyamic acid solution (B-3).

(Synthesis Example 4)
3.18 g (8.00 mmol) of DA-3, 2.38 g (6.00 mmol) of DA-9, 1.79 g of DA-10 ( 6.00 mmol) was weighed, 66.2 g of NMP was added, and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.25 g (19.5 mmol) of CA-4 was added, 18.9 g of NMP was further added, and the mixture was stirred at 50°C for 15 hours under a nitrogen atmosphere to obtain a polyamic acid solution. Obtained. The viscosity of this polyamic acid solution at a temperature of 25° C. was 264 mPa·s.

15.3 g of this polyamic acid solution was placed in a 100 mL Erlenmeyer flask containing a stirrer, and NMP containing 0.300 g of NMP, 10.3 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was added. 1.54 g of the solution and 6.86 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyamic acid solution (B-4).

(Example 3)
5.42 g of the polyamic acid solution (A-1) obtained in Example 1 and 5.41 g of the polyamic acid solution (B-1) obtained in Synthesis Example 1 were placed in a 50 mL Erlenmeyer flask containing a stirrer. It was weighed and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-3).

(Example 4)
5.50 g of the polyimide solution (A-2) obtained in Example 2 and 5.51 g of the polyimide solution (B-2) obtained in Synthesis Example 2 were weighed into a 50 mL Erlenmeyer flask containing a stirrer. , and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-4).

(Example 5)
5.42 g of the polyamic acid solution (B-1) obtained in Synthesis Example 1 and 5.42 g of the polyamic acid solution (B-3) obtained in Synthesis Example 3 were placed in a 50 mL Erlenmeyer flask containing a stirrer. It was weighed and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-5).

(Example 6)
5.62 g of the polyamic acid solution (A-1) obtained in Example 1 and 5.62 g of the polyamic acid solution (B-4) obtained in Synthesis Example 4 were placed in a 50 mL Erlenmeyer flask containing a stirrer. It was weighed and stirred with a magnetic stirrer for 2 hours to obtain a liquid crystal aligning agent (A-6).

<Evaluation of seal adhesive strength>
The liquid crystal aligning agents obtained in Examples and Synthesis Examples were filtered through a 1.0 μm filter, spin-coated onto a glass substrate with a transparent electrode, dried on a hot plate at 80° C. for 2 minutes, and dried at 230° C. for 20 minutes. After baking for a minute, a coating film having a film thickness of 100 nm was obtained. Two substrates thus obtained were prepared, and after spraying 4 μm bead spacers on the liquid crystal alignment film surface of one of the substrates, a sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was dropped. Then, the liquid crystal alignment film surface of the other substrate was turned inside, and the substrates were laminated together so that the overlap width of the substrates was 1 cm. At that time, the amount of the sealant dropped was adjusted so that the diameter of the sealant after bonding was about 3 mm. After fixing the two bonded substrates with a clip, they were thermally cured at 120° C. for 1 hour to prepare a sample for adhesion evaluation.

Next, the prepared sample was fixed at the edges of the upper and lower substrates with a tabletop precision universal testing machine AGS-X 500N manufactured by Shimadzu Corporation, and then pushed from the upper part of the center of the substrate. (N) was evaluated as seal adhesive strength.

(Examples 7-12)
After filtering each of the liquid crystal aligning agents (A-1) to (A-6) obtained in Examples 1 to 6 with a 1.0 μm filter, a sample for adhesion evaluation was prepared and sealed as described above. Table 4 shows the results of evaluating the adhesive force.

(Comparative Examples 1 to 4)
After filtering each of the liquid crystal aligning agents (B-1) to (B-4) obtained in Synthesis Examples 1 to 4 with a 1.0 μm filter, a sample for adhesion evaluation was prepared and sealed as described above. Table 4 shows the results of evaluating the adhesive force.

When the liquid crystal aligning agent described in Examples was used, the seal adhesive strength was high and favorable.

(Example 13)
4.30 g (17.6 mmol) of DA-1, 2.67 g (4.80 mmol) of DA-2, 3.27 g of DA-4 ( 9.57 mmol) was weighed, 75.1 g of NMP was added, and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.66 g (20.7 mmol) of CA-1 was added, 9.34 g of NMP was further added, and the mixture was stirred at 40° C. for 3 hours under a nitrogen atmosphere. Further, 1.78 g (9.08 mmol) of CA-2 was added, and 8.00 g of NMP was added, and the mixture was stirred at 23° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25° C. was 304 mPa·s.

90.0 g of this polyamic acid solution was placed in a 500 mL Erlenmeyer flask containing a stirrer, 79.0 g of NMP, 7.92 g of acetic anhydride and 2.04 g of pyridine were added and stirred at room temperature for 30 minutes. , and 55° C. for 3 hours. This reaction solution was poured into 700 g of methanol, and the obtained precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at a temperature of 60° C. to obtain polyimide powder. The imidization rate of this polyimide powder was 70%.

6.07 g of this polyimide powder was placed in a 200 mL Erlenmeyer flask equipped with a stirrer, 44.5 g of NMP was added, and the mixture was dissolved by stirring at 50° C. for 20 hours. Furthermore, 20.3 g of this solution was placed in a 200 mL Erlenmeyer flask containing a stirrer, and an NMP solution containing 4.37 g of NMP, 16.2 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was prepared. 2.43 g and 10.8 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyimide solution (A-7).

(Example 14)
4.30 g (17.6 mmol) of DA-1, 2.67 g (4.80 mmol) of DA-2, 1.91 g of DA-3 ( 4.80 mmol), 1.64 g (4.80 mmol) of DA-4 was weighed, 77.1 g of NMP was added, and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 4.66 g (20.7 mmol) of CA-1 was added, 8.88 g of NMP was further added, and the mixture was stirred at 40° C. for 3 hours under a nitrogen atmosphere. Further, 1.71 g (8.69 mmol) of CA-2 was added, 8.00 g of NMP was added, and the mixture was stirred at 23° C. for 4 hours under nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25° C. was 312 mPa·s.

90.0 g of this polyamic acid solution was placed in a 500 mL Erlenmeyer flask containing a stirrer, 79.0 g of NMP, 7.02 g of acetic anhydride and 1.81 g of pyridine were added and stirred at room temperature for 30 minutes. , and 55° C. for 3 hours. This reaction solution was poured into 700 g of methanol, and the obtained precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at a temperature of 60° C. to obtain polyimide powder. The imidization rate of this polyimide powder was 71%.

6.03 g of this polyimide powder was placed in a 200 mL Erlenmeyer flask equipped with a stirrer, 44.2 g of NMP was added, and the mixture was dissolved by stirring at 50° C. for 20 hours. Furthermore, 21.0 g of this solution containing a 200 mL Erlenmeyer flask containing a stirrer was taken, and 2 NMP solutions containing 4.48 g of NMP, 16.8 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane were added. 0.52 g and 11.2 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyimide solution (A-8).

(Synthesis Example 5)
4.30 g (17.6 mmol) of DA-1 and 5.73 g (14.3 mmol) of DA-3 were weighed into a 1 L four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 73.6 g of NMP was added. , was dissolved by stirring under nitrogen. While stirring this diamine solution under water cooling, 4.66 g (20.7 mmol) of CA-1 was added, 9.69 g of NMP was further added, and the mixture was stirred at 40° C. for 3 hours under a nitrogen atmosphere. Further, 1.50 g (7.65 mmol) of CA-2 was added, and 8.53 g of NMP was added, and the mixture was stirred at 23° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25° C. was 290 mPa·s.

90.0 g of this polyamic acid solution was placed in a 500 mL Erlenmeyer flask containing a stirrer, 79.0 g of NMP, 8.16 g of acetic anhydride and 2.10 g of pyridine were added and stirred at room temperature for 30 minutes. , and 55° C. for 3 hours. This reaction solution was poured into 700 g of methanol, and the obtained precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at a temperature of 60° C. to obtain polyimide powder. The imidization rate of this polyimide powder was 72%.

6.10 g of this polyimide powder was placed in a 200 mL Erlenmeyer flask equipped with a stirrer, 44.7 g of NMP was added, and the mixture was dissolved by stirring at 50° C. for 20 hours. Furthermore, 25.0 g of this solution was placed in a 200 mL Erlenmeyer flask containing a stirrer, and an NMP solution containing 4.90 g of NMP, 19.8 g of GBL, and 1% by mass of 3-glycidoxypropyltriethoxysilane was prepared. 3.00 g and 13.3 g of BCS were added and stirred with a magnetic stirrer for 2 hours to obtain a polyimide solution (B-5).

<Evaluation of liquid crystal orientation>
Below, the manufacturing method of the liquid crystal cell for evaluating liquid crystal orientation is shown.

A liquid crystal cell having the structure of an FFS liquid crystal display element is manufactured. First, a substrate with electrodes was prepared. The substrate is a glass substrate with a size of 30 mm×35 mm and a thickness of 0.7 mm. An IZO electrode forming a counter electrode is formed on the entire surface of the substrate as a first layer. A SiN (silicon nitride) film formed by a CVD method is formed as a second layer on the counter electrode of the first layer. The SiN film of the second layer has a film thickness of 100 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film is arranged as a third layer to form two pixels, a first pixel and a second pixel. are doing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode on the third layer has a comb-like shape formed by arranging a plurality of V-shaped electrode elements with bent central portions. The width of each electrode element in the lateral direction is 3 μm, and the interval between electrode elements is 6 μm. Since the pixel electrode that forms each pixel is configured by arranging a plurality of V-shaped electrode elements with a bent central portion, the shape of each pixel is not rectangular, but the central portion is the same as the electrode element. It has a shape resembling a bold, Chinese character that bends at the . Each pixel is vertically divided by the curved portion in the center, and has a first region above the curved portion and a second region below the curved portion.

Comparing the first region and the second region of each pixel, the formation direction of the electrode elements of the pixel electrodes constituting them is different. That is, when the rubbing direction of the liquid crystal alignment film, which will be described later, is used as a reference, in the first region of the pixel, the electrode element of the pixel electrode is formed to form an angle of +10° (clockwise), and in the second region of the pixel, , the electrode elements of the pixel electrode are formed at an angle of −10° (clockwise). That is, in the first region and the second region of each pixel, the direction of the rotational movement (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode within the substrate plane is They are configured to be opposite to each other.

Next, the liquid crystal aligning agents obtained in Examples and Synthesis Examples were filtered through a 1.0 μm filter, and then applied to the prepared substrate with electrodes by spin coating. After drying on a hot plate at 80° C. for 2 minutes, baking was performed in a hot air circulating oven at 230° C. for 20 minutes to obtain a polyimide film with a film thickness of 60 nm. This polyimide film is rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 500 rpm, moving speed: 30 mm/sec, indentation length: 0.3 mm, rubbing direction: tilted at 10° with respect to the third-layer IZO comb-teeth electrode. After that, it was cleaned by irradiating ultrasonic waves in pure water for 1 minute, and water droplets were removed by blowing air. Then, it dried at 80 degreeC for 15 minutes, and obtained the board|substrate with a liquid crystal aligning film. In addition, a polyimide film was formed in the same manner as described above on a glass substrate having columnar spacers with a height of 4 μm, and an ITO electrode was formed on the back surface as the counter substrate. A substrate with the applied liquid crystal alignment film was obtained. These two substrates with a liquid crystal alignment film are used as one set, and a sealant is printed on the substrate with the liquid crystal injection port left. It was pasted together so that it would be After that, the sealant was cured to produce an empty cell with a cell gap of 4 μm. Liquid crystal MLC-3019 (manufactured by Merck & Co.) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain an FFS liquid crystal cell. After that, the obtained liquid crystal cell was heated at 120° C. for 1 hour, left overnight at 23° C., and then used for evaluation of liquid crystal orientation.

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

After standing, the liquid crystal cell was placed between two polarizing plates arranged so that the polarizing axes were perpendicular to each other, and the backlight was turned on with no voltage applied so that the brightness of the transmitted light was minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel was the darkest to the angle at which the first region was the darkest was calculated as the angle Δ. Similarly, for the second pixel, the second region and the first region were compared to calculate a similar angle Δ. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. That is, the smaller this angle, the better the liquid crystal orientation.

(Examples 15-18)
After filtering each of the liquid crystal aligning agents (A-2), (A-4), (A-7) and (A-8) obtained in Examples 2, 4, 13 and 14 with a 1.0 μm filter Table 5 shows the results of evaluation of the seal adhesive force by preparing samples for adhesion evaluation as described above and the results of the angle Δ of the liquid crystal cell.

(Comparative Example 5)
After filtering the liquid crystal aligning agent (B-5) obtained in Synthesis Example 5 with a 1.0 μm filter, a sample for adhesion evaluation was prepared as described above and the seal adhesive strength was evaluated. Table 5 shows the results for the cell angle Δ.

When the liquid crystal aligning agent described in Examples was used, the seal adhesive strength was high, and the angle Δ of the liquid crystal cell after aging was small, and the liquid crystal alignment was good.

The liquid crystal aligning agent of the present invention can solve display unevenness near the frame by increasing the adhesiveness between the sealant and the liquid crystal alignment film in a narrow frame liquid crystal display element that can secure a large number of display surfaces. Useful.

Claims (6)

a diamine component containing at least one diamine selected from component (A) below, a diamine containing a skeleton of component (C) below, and a diamine represented by the following formula (3); and a tetracarboxylic dianhydride. A liquid crystal aligning agent characterized by containing at least one polymer selected from polyimides which are imidized products of polyamic acid which is a reaction product of (1) and whose imidization rate is 70% or more.
Component (A): a diamine having at least one structure selected from the following formulas (1-1) and (1-2)

(In the formula, D represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, and D may have various substituents. , E is a single bond, or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, an unsaturated hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic ring, F is a single bond or an ether bond (-O- ), represents an ester bond (-OCO-, -COO-), m is 1 or 0, R represents a thermally leaving group, * represents a bond with another atom, and represents an amino group include.)
Component (C): a diamine having at least one structure selected from the following formulas (a) and (b)

(In the formula, X ¹ is an oxygen atom or a sulfur atom, A ¹ to A ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and the total number of carbon atoms is 1 to 9. Moreover, * represents a bond with another atom.)
Formula (3) diamine;

In the above formula (3), Y is a divalent organic group other than a phenylene group, and from the following formulas (Y-1) to (Y-5) and formulas (Y-9) to (Y-99) At least one selected.

(In the above formula (Y-90), m and n are each an integer of 1 to 11, m+n is an integer of 2 to 12, and h is an integer of 1 to 3 in the above formula (Y-95). and j is an integer of 0 to 3 in the above formulas (Y-92) and (Y-98).) A liquid crystal alignment film comprising a polymer obtained from the liquid crystal alignment agent according to claim 1 and having an aromatic heterocycle and a primary amino group and a secondary amino group in its structure. 3. The film according to claim 2, which is a film made of a calcined material, and is characterized in that the skeleton of the aromatic heterocycle, the primary amino group, and the secondary amino group are contained in the structure generated by calcination. Liquid crystal alignment film. 4. The liquid crystal alignment film according to claim 2, wherein the aromatic heterocycle is a pyridine skeleton, a benzimidazole skeleton, or an imidazole skeleton. 4. The liquid crystal alignment film according to claim 3, wherein the fired product is produced at a firing temperature of 100.degree. C. to 300.degree. A liquid crystal display device comprising the liquid crystal alignment film according to any one of claims 2 to 5.