CN110998424B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element using same - Google Patents

Abstract

The invention provides a liquid crystal aligning agent, a liquid crystal aligning film and a liquid crystal display element using the same, wherein the liquid crystal aligning agent can form the liquid crystal aligning film for the liquid crystal display element with good viewing angle characteristics and afterimage characteristics. The liquid crystal aligning agent contains a polymer which is a reaction product derived from a raw material containing tetracarboxylic dianhydride and diamine, and the raw material for synthesizing the polymer contains a specific diamine in which a plurality of phenylene groups are linked through an alkylene group, and contains at least one selected from a specific diamine containing nitrogen, and a specific tetracarboxylic dianhydride containing a divalent group containing an unsaturated bond.

Description

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

Technical Field

The present invention relates to a liquid crystal aligning agent for forming a liquid crystal alignment film, a diamine, a liquid crystal alignment film formed using the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal alignment film.

Background

As a liquid crystal display device, a liquid crystal display device of a vertical electric field type such as a Twisted Nematic (TN) type, a super Twisted Nematic (Super Twisted Nematic, STN) type, a vertical alignment (Vertical Alignment, VA) type, or a transverse electric field type is known In which electrodes are formed only on one side of a pair of substrates disposed opposite to each other and an electric field is generated In a direction parallel to the substrates, such as an In-Plane Switching (IPS) type or a fringe field Switching (Fringe Field Switching, FFS) type. Among them, the in-plane switching (IPS) mode or FFS mode liquid crystal display device has excellent viewing angle characteristics and color reproducibility, and is used in various liquid crystal display devices such as televisions, input panels, and smart phones (patent document 1).

A liquid crystal alignment film, which is one of the constituent members used in a liquid crystal display element, is an important member related to display quality. In recent years, with the improvement in quality of liquid crystal display devices, liquid crystal alignment films have been demanded to have various and high performance. In particular, in a liquid crystal display element of a transverse electric field system, the following liquid crystal alignment film is required in order to further improve viewing angle characteristics and color reproducibility in black display: in addition to the low pretilt angle of the liquid crystal, it is required to supply a liquid crystal display element which does not generate an afterimage, that is, a residual Direct Current (DC) which is small in accumulation after voltage application and after voltage interruption (OFF) and which is quick in charge relaxation (patent documents 2 and 3).

Prior art literature

Patent literature

Patent document 1: international publication No. 1998/027454

Patent document 2: international publication No. 2015/080185

Patent document 3: international publication No. 2015/050135

Disclosure of Invention

Problems to be solved by the invention

As in patent document 2 and patent document 3, liquid crystal alignment films having various properties have been proposed so far, but the present inventors have found that a liquid crystal alignment agent for forming a liquid crystal alignment film having both of these properties has not been proposed.

Accordingly, an object of the present invention is to provide a liquid crystal alignment film of a liquid crystal display element capable of suppressing a pretilt angle of liquid crystal to be low, suppressing accumulation of residual DC and rapidly relaxing electric charges, and a liquid crystal alignment agent capable of forming the liquid crystal alignment film. The present invention also provides a liquid crystal display element having the liquid crystal alignment film and having excellent viewing angle characteristics and afterimage characteristics.

Technical means for solving the problems

The inventors have found that: the liquid crystal alignment agent containing a polymer as one of the raw materials for synthesis can form a liquid crystal alignment film of a liquid crystal display element capable of suppressing the pretilt angle of liquid crystal to be low, and supplying residual DC to be small and alleviating charges quickly, wherein the polymer contains at least one compound selected from the compounds represented by the following formulas (1) to (3), and at least one compound selected from the compounds represented by the following formulas (A) to (C) and the compound represented by the following formula (D). Further, it has been found that a liquid crystal display element having the liquid crystal alignment film is excellent in viewing angle characteristics and afterimage characteristics, and the present invention has been achieved.

[ chemical 1]

[ chemical 2]

[ chemical 3]

In the formula (1), m is an integer of 3 to 8, n is an integer of 1 to 3, in the formula (1) to (3), a group in which a bonding position is not fixed to any carbon atom constituting a ring represents that a bonding position in the ring is arbitrary, in the formula (A), A ¹ Is, or contains, nitrogenHeterocycle, W ¹ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ¹ Is hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, a is independently 0 or 1, in the formula (B), A ² Independently nitrogen, or a heterocycle containing nitrogen, W ² W and W ³ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ² Independently hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, a is independently 0 or 1, in the formula (C), Z ³ In the formula (D), T is a divalent unsaturated bond-containing group containing 1 to 2 carbon-carbon double bonds or 1 to 2 carbon-carbon triple bonds, and in the formulas (1) to (3) and (A) to (C), a group whose bonding position is not fixed to any carbon atom constituting a ring represents that the bonding position in the ring is arbitrary, and in the formula (1), when m is 8, the diamine may not contain any of the compounds represented by the formulas (A) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the following formula (D).

ADVANTAGEOUS EFFECTS OF INVENTION

By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film of a liquid crystal display element can be obtained in which the pretilt angle of liquid crystal is suppressed to be low, the accumulation of residual DC is small, and the relaxation of electric charge is rapid. In addition, the liquid crystal display element having the liquid crystal alignment film is excellent in viewing angle characteristics and afterimage characteristics.

Detailed Description

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. In the present specification, unless otherwise specified, the measurement of the operation, physical properties, and the like is performed under the condition of room temperature (20 ℃ or more and 25 ℃ or less)/relative humidity 40% rh or more and 50% rh or less.

The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing a polymer (hereinafter, simply referred to as "polymer", or "polymer" of the present invention) as one of raw materials for synthesis, the polymer containing at least one compound selected from the group consisting of compounds represented by the following formulas (1) to (3), and containing at least one compound selected from the group consisting of compounds represented by the following formulas (a) to (C), and compounds represented by the following formulas (D).

[ chemical 4]

[ chemical 5]

[ chemical 6]

In the formula (1), m is an integer of 3 to 8, n is an integer of 1 to 3, in the formula (1) to (3), a group in which a bonding position is not fixed to any carbon atom constituting a ring represents that a bonding position in the ring is arbitrary, in the formula (A), A ¹ Is nitrogen, or a heterocycle containing nitrogen, W ¹ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ¹ Is hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r is an integer of 0 or more, a is independently 0 or 1, and A in the formula (B) ² Independently nitrogen, or a heterocycle containing nitrogen, W ² W and W ³ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ² Independently hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r is an arbitrary integer of 0 or more, a is independently 0 or 1, Z in formula (C) ³ Is a monovalent organic group containing at least one of a secondary or tertiary amino group, wherein T is a group containing 1 to 2 carbon-carbon double bonds or 1 to 2The divalent unsaturated bond-containing group of the carbon-carbon triple bond is represented by any of the formulas (1) to (3) and (a) to (C), and the bonding position of the group not fixed to any of the carbon atoms constituting the ring is represented by any of the rings, and when m is 8 in the formula (1), the diamine may not contain any of the compounds represented by the formulas (a) to (C), and the tetracarboxylic dianhydride may not be represented by the formula (D). With the above configuration, a liquid crystal alignment film can be provided in which the pretilt angle of the liquid crystal is suppressed to be low, the residual DC is small in accumulation, and the charge is relaxed quickly.

In an embodiment of the present invention, there is provided a liquid crystal aligning agent comprising at least one polymer comprising a constituent unit derived from a raw material comprising at least one selected from the group consisting of the compounds represented by the formulas (1) to (3), and at least one selected from the group consisting of the formulas (a), (B), (C) and (D), wherein when m is 8 in the formula (1), the diamine may not comprise any of the compounds represented by the formulas (a) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the formula (D). In the above embodiment, the polymer is at least one selected from the group consisting of polyamic acid, polyimide, partially polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide. Wherein, when m is 8 in the formula (1), the diamine may not include any of the compounds represented by the formulas (a) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the formula (D). In this specification, "a polymer as a reaction product derived from a raw material including …" may also be "a polymer including a constituent unit derived from a raw material".

Further, in an embodiment of the present invention, there is provided a method for producing a liquid crystal aligning agent containing at least one kind of polymer as a reaction product derived from a raw material containing tetracarboxylic dianhydride and diamine, and the method comprises reacting at least one kind selected from the group of compounds represented by the formulas (a) to (3) and at least one kind selected from the group of compounds represented by the formulas (a) to (C) as a raw material for synthesizing the polymer, wherein the polymer is at least one kind selected from the group consisting of polyamic acid, polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide, and when m is 8 in the formula (1), the diamine may not contain any one kind of compounds represented by the formulas (a) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the formula (D).

In addition, in the embodiment of the present invention, there is also provided use (application) of the polymer of the present invention as a liquid crystal aligning agent.

In the present specification, a state in which the polymer is dissolved in an organic solvent is referred to as a varnish. The method for producing the varnish is not particularly limited, and a mixture of a polymer obtained by reacting a mixture of raw materials including tetracarboxylic dianhydride (including a derivative thereof) and diamine (including dihydrazide) in an organic solvent may be used as the varnish directly for producing the liquid crystal aligning agent. In addition, the polymer recovered from the reaction mixture and redissolved in an organic solvent may be used as a varnish for producing a liquid crystal aligning agent. The liquid crystal aligning agent of the present invention is a solution containing a varnish mainly composed of a polymer dissolved in an organic solvent, and two or more kinds of varnishes may be used, wherein the polymer is selected from the group consisting of polyamic acid, polyimide, partially polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide. In a preferred embodiment of the present invention, the polyimide-based liquid crystal alignment film is formed by applying the liquid crystal alignment agent to a substrate and then forming a film by means of heating or the like.

More specifically, the liquid crystal aligning agent of the present invention comprises at least one polymer obtained by reacting at least one compound selected from the group consisting of compounds represented by the formulas (1) to (3), and at least one compound selected from the group consisting of compounds represented by the formulas (a) to (C), and compounds represented by the formulas (D), as a raw material for synthesis, wherein when m is 8 in the formula (1), the diamine may not comprise any of the compounds represented by the formulas (a) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the formula (D). In addition, in an embodiment of the present invention, a liquid crystal aligning agent contains at least one of polymers as a reaction product derived from a raw material containing tetracarboxylic dianhydride and diamine, and a raw material for synthesizing the polymer contains at least one selected from the group of compounds represented by the formulas (1) to (3), and contains at least one selected from the group of compounds represented by the formulas (a) to (C), and contains at least one selected from the group of compounds represented by the formulas (D). In addition, in the embodiment of the present invention, the liquid crystal aligning agent contains a polymer which is a reaction product derived from a raw material containing tetracarboxylic dianhydride and diamine, more specifically, the liquid crystal aligning agent in the embodiment of the present invention contains a polymer using a raw material containing at least one selected from the group of compounds represented by the formulas (1) to (3) and containing at least one selected from the group of compounds represented by the formulas (a) to (C) and the compound represented by the formula (D) (in some embodiments, in a form of laminating 1 layer on a substrate, and thus may be also referred to as "single layer"). That is, in an embodiment of the present invention, one of the polymers is contained. In addition, in an embodiment of the present invention, two or more kinds of the above-mentioned polymers are contained (in an embodiment, in a form of laminating 2 or more layers on a substrate, this may be also referred to as a "blend system"). The liquid crystal aligning agent according to the embodiment of the present invention contains the polymer (P) and the polymer (Q) as raw materials for synthesis. That is, in an embodiment of the present invention, at least two of the polymers are contained, the at least two polymers including a polymer (P) and a polymer (Q); the raw material for synthesizing the polymer (P) contains at least one selected from the group of compounds represented by the formulas (1) to (3); the raw material for synthesizing the polymer (Q) includes at least one selected from the group of compounds represented by the formulas (a) to (C) and the compound represented by the formula (D).

In the present invention, the polymer is at least one selected from the group consisting of polyamic acid, polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide. In addition, in this specification, these include derivatives of these. For example, the polymer is a polyamic acid or derivative thereof.

The compounds represented by the formulas (1) to (3) will be described.

[ chemical 7]

In the formula (1), m is an integer of 3 to 8, more specifically, m is 3, 4, 5, 6, 7 or 8. Here, when m is 8, it is preferable in particular in terms of suppressing the pretilt angle to be low. In addition, when m is 3, it is also preferable in particular in terms of showing good liquid crystal alignment.

In the formula (3), n is an integer of 1 to 3.

In the formulae (1) to (3), a group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position in the ring is arbitrary. In the embodiment of the present invention, the bonding position of the amino group to the ring is preferably meta-position or para-position to ensure the following linearity.

By using at least one of the compounds represented by the above-mentioned formulas (1), (2) and (3) as a raw material for synthesis, the stable configuration (formation) of the obtained polymer is very linear, and therefore it is considered that the pretilt angle of the liquid crystal can be suppressed to be low.

Suitable specific examples of the compounds represented by the formulae (1) to (3) are shown below.

[ chemical 8]

[ chemical 9]

[ chemical 10]

Among them, the compounds represented by the formulas (1-1), (1-4), (2-1) and (3-1) are preferable because they exhibit high liquid crystal alignment and can further suppress the pretilt angle of the liquid crystal to be low. In particular, at least one of the formulae (1-1) and (1-4) is preferable because of its excellent solubility in an organic solvent. As described above, in the present invention, there is also provided a diamine represented by the formula (1-4). By using the diamine represented by the above formula (1-4) as a diamine raw material among raw materials for synthesizing a polymer used for a liquid crystal aligning agent, a liquid crystal alignment film of a liquid crystal display element can be formed which can specifically suppress the pretilt angle of liquid crystal to be low, and which is small in the accumulation of residual DC and quick in the relaxation of electric charge. In addition, by using only the diamine represented by the above formula (1-4) as a diamine raw material among raw materials for synthesizing a polymer used in a liquid crystal aligning agent, the pretilt angle of a liquid crystal can be suppressed to be low specifically. Accordingly, in the present invention, there is also provided a liquid crystal aligning agent comprising at least one of polymers as a reaction product derived from a raw material comprising tetracarboxylic dianhydride and diamine, and the diamine comprising only the diamine represented by the formula (1-4). In the case of using the diamine represented by the above formula (1-4) as a diamine raw material in a raw material for synthesizing a polymer used for a liquid crystal aligning agent, the acid dianhydride is not particularly limited. The method for synthesizing the diamine represented by the above formula (1-4) is exemplified by the methods described in the examples section, but is not limited thereto.

The compounds represented by the formulas (a) to (D) will be described.

[ chemical 11]

[ chemical 12]

In the formula (A), A ¹ Is nitrogen, or a heterocycle containing nitrogen, W ¹ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ¹ Is hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r is an integer of 0 or more, and a is independently 0 or 1. Here, the nitrogen-containing heterocycle in this specification is a concept including a nitrogen-containing heterocycle and a nitrogen-containing aliphatic ring. In addition, the nitrogen-containing heterocyclic ring may contain a heteroatom such as an oxygen atom or a sulfur atom in addition to the nitrogen atom. In the present specification, r is an arbitrary integer in A ¹ In the case of a nitrogen-containing heterocycle, the number of rings to be condensed, or the number of nitrogen atoms or hetero atoms to be contained, is not particularly specified, and may be an integer of 1 to 10, for example. In the present specification, the "protecting group substituted with a hydrogen atom by heat" is not particularly limited as long as it is a protecting group substituted with a hydrogen atom by heat, and examples thereof are appropriately given: boc (short for t-butoxycarbonyl), benzyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, allyloxycarbonyl and the like.

In the formula (B), A ² Independently nitrogen, or a heterocycle containing nitrogen, W ² W and W ³ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ² Independently hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r is an integer of 0 or more, and a is independently 0 or 1.

In the formula (C), Z ³ Is a monovalent organic group containing at least one of a secondary or tertiary amino group.

In the formula (D), T is a divalent unsaturated bond-containing group containing 1 to 2 carbon-carbon double bonds or 1 to 2 carbon-carbon triple bonds. In an embodiment of the present invention, T comprises an arylene group having 6 to 12 carbon atoms. In the formula (1), when m is 8, T may be an alkylene group, and preferably the alkylene group has 2 to 16 carbon atoms, more preferably 2 to 8 carbon atoms, and still more preferably 4 to 8 carbon atoms.

In the formulae (1) to (3) and (a) to (C), a group whose bonding position is not fixed to any carbon atom constituting the ring indicates that the bonding position in the ring is arbitrary.

In an embodiment of the present invention, the compounds represented by the formulas (a) to (C) have nitrogen (in particular, secondary amino group, tertiary amino group) or a nitrogen-containing heterocycle. These groups are considered to function as groups that promote migration of charges in the liquid crystal alignment film, and play a role of rapidly relaxing the accumulated charges. In addition, the compound represented by formula (D) has pi electron clouds distributed throughout the molecule. Therefore, since the polymer obtained by reacting the compounds represented by the formulas (a) to (C) with the compound represented by the formula (D) has high conjugation, it is considered that when the polymer is used as a liquid crystal alignment film, the volume resistance value is reduced to reduce the accumulation of residual DC and to contribute to rapid relaxation of electric charges. In the case where m is 8 in the above formula (1), the compounds represented by the formulas (a) to (D) are not essential as diamines, and thus the effect of surprisingly reducing the pretilt angle can be exhibited. The acid dianhydride to be reacted is not particularly limited, and may be a compound represented by the formula (D), a compound represented by any one of (AN-1) to (AN-18), or other known compounds.

Specific examples of the compounds represented by the formulas (a) to (D) are shown below.

[ chemical 13]

[ chemical 14]

[ 15]

[ 16]

[ chemical 17]

[ chemical 18]

In the formulae (A-1) to (A-11), the group whose bonding position is not fixed to any carbon atom constituting the ring means that the bonding position in the ring is arbitrary. In the formula (B-3), k is an integer of 1 to 5, more specifically 1, 2, 3, 4 or 5. In the formula (B-4), n is an integer of 1 to 3, more specifically 1, 2 or 3.

Among them, at least one of the above-mentioned formula (A-12), formula (A-14), formula (A-15), formula (A-16), formula (A-17), formula (A-19), formula (B-3), formula (B-5), formula (C-2), formula (C-3), formula (D-2) and formula (D-3) is preferable. In particular, the formulas (B-3) and (D-2) are preferable because they reduce the accumulation of residual DC and the charge is particularly fast to alleviate. In addition, the expression (a-15) is more preferable because it not only reduces the accumulation of residual DC and reduces the charge rapidly, but also has a good voltage holding ratio. Here, in the formula (B-3), k=2 is more preferable.

According to an embodiment of the present invention, the compound represented by the formula (1) to (3) is at least one selected from the group of compounds represented by the formula (1-1) to (1-4), the formula (2-1), the formula (2-2), and the formula (3-1) to (3-6); the compound represented by the formula (A) to the formula (C) is at least one selected from the group of the compounds represented by the formula (A-1) to the formula (A-20), the formula (B-1) to the formula (B-8) and the formula (C-1) to the formula (C-3); the compound represented by the formula (D) is at least one selected from the group of compounds represented by the formulas (D-1) to (D-4). According to the embodiment, the desired effects of the present invention can be effectively exhibited.

In an embodiment of the present invention, the compound represented by the formula (1) to the formula (3) is at least one selected from the group consisting of the compounds represented by the formula (1-1), the formula (1-4), the formula (2-1), and the formula (3-1); the compound represented by the formula (A) to the formula (C) is at least one selected from the group of compounds represented by the formula (A-12), the formula (A-14), the formula (A-15), the formula (A-16), the formula (A-17), the formula (A-19), the formula (A-20), the formula (B-3), the formula (B-5), the formula (C-2) and the formula (C-3); the compound represented by the formula (D) is at least one selected from the group of the compounds represented by the formula (D-2) and the formula (D-3). According to the embodiment, the desired effects of the present invention can be effectively exhibited.

In the embodiment of the present invention, in order to obtain a liquid crystal display element having a small residual DC accumulation, a fast charge relaxation, and excellent image retention characteristics, it is also preferable to use at least one compound represented by the formulas (a) to (C) in combination with at least one compound represented by the formula (D). Thus, according to an embodiment of the present invention, the raw material for synthesizing the polymer includes at least one selected from the group of compounds represented by the formulas (1) to (3), and includes at least one selected from the group of compounds represented by the formulas (a) to (C), and includes at least one selected from the compounds represented by the formulas (D).

In the present invention, in a form including at least one selected from the group consisting of the compounds represented by the formulas (1) to (3) and the compound represented by the formula (B) as a raw material for synthesizing the polymer, the content of the compound represented by the formula (C) relative to the total amount of diamine is preferably reduced intentionally, and is preferably less than 30 mol%, more preferably less than 20 mol%, still more preferably less than 10 mol%, still more preferably less than 5 mol%, still more preferably less than 4 mol%, still more preferably less than 3 mol%, still more preferably less than 2 mol%, still more preferably less than 1 mol%, still more preferably substantially not included, with respect to the total amount of diamine used. The term "substantially not including" as used herein means that the amount of the diamine used is less than 0.1 mol%. Here, if the content is 30 mol% or more, the characteristics of the DC residual image may be deteriorated.

In the case of including one of the polymers according to the embodiments of the present invention, in a form including at least one selected from the group of compounds represented by the formulas (1) to (3) and the compound represented by the formula (C) as a raw material for synthesizing the polymer, it is preferable to further combine at least one of the compound represented by the formula (a) and the compound represented by the formula (B) (in particular, the compound represented by the formula (a)). Here, when at least one of the compound represented by the formula (a) and the compound represented by the formula (B) (in particular, the compound represented by the formula (a)) is not used, there is a concern that the orientation may be deteriorated. In the embodiment of the present invention, when the compound represented by the formula (C) is added, the compound represented by the formula (a) is used in combination, thereby improving the DC residual image characteristics.

In the case where one of the polymers is contained in the present invention, in the form of combining the compound represented by the formula (1-1) with the compound represented by the formula (B-3) as a raw material for synthesizing the polymer, the content of the compound represented by the formula (1-1) relative to the total amount of diamine used is preferably more than 90 mol%, more preferably 92 mol% or more, and even more preferably 95 mol% or more relative to the total amount of diamine used for synthesizing the polymer in order to suppress the pretilt angle of the liquid crystal to be low. In order to reduce the residual DC accumulation and accelerate the charge relaxation while keeping the electric characteristics such as the voltage holding ratio, the amount is preferably not too much, specifically, preferably less than 90 mol%, more preferably 88 mol% or less, still more preferably 86 mol% or less, still more preferably 84 mol% or less, still more preferably 82 mol% or less, still more preferably 80 mol% or less, and may be 78 mol% or less, 76 mol% or less, 74 mol% or less, or 72 mol% or less.

In embodiments of the present invention, where one of the polymers is included, the starting materials for synthesizing the polymer may also include (in combination): at least one selected from the group of compounds represented by formula (A-12), formula (A-14), formula (A-15), formula (A-16), formula (A-17), formula (A-19), formula (B-3), formula (B-5), formula (C-2), and formula (C-3); and at least one selected from the group of compounds represented by the formula (D-2) and the formula (D-3). In addition, according to an embodiment of the present invention, the raw materials for synthesizing the polymer more preferably include (and use): at least one compound selected from the group consisting of compounds represented by the formula (A-15) and the formula (B-3); in the formula (B-3), k=2 is more preferable as the compound represented by the formula (D-2).

In the embodiment of the present invention, in the liquid crystal aligning agent comprising at least one kind of polymer obtained by reacting at least one kind of compound represented by the above formulas (1) to (3) with at least one kind of compound represented by the above formulas (a) to (C) and compound represented by the above formula (D), the amount of the compound represented by the above formulas (1) to (3) used for synthesizing the above polymer is preferably 27 mol% or more, more preferably 29 mol% or more, still more preferably 31 mol% or more, still more preferably 32 mol% or more, still more preferably 33 mol% or more, still more preferably 34 mol% or more, with respect to the total amount of diamine used for synthesizing the polymer (the total amount of diamine (100 mol%) in the case that two or more kinds of polymers are contained in the liquid crystal aligning agent). For the purpose of reducing the volume resistance, it is preferable to use 99 mol% or less, 98 mol% or less, 96 mol% or less, 94 mol% or less, 92 mol% or less, 90 mol% or less, 88 mol% or less, 86 mol% or less, 84 mol% or less, or 82 mol% or less. In the embodiment of the present invention, the amount of the compound represented by the formulas (a) to (C) is preferably 0 mol% or more, more preferably more than 0 mol%, still more preferably 1 mol% or more, still more preferably 2 mol% or more, still more preferably 3 mol% or more, still more preferably 4 mol% or more, still more preferably 5 mol% or more, still more preferably 6 mol% or more, based on the total amount of diamines (100 mol%) used for synthesizing the polymer (in the case where two or more polymers are included in the liquid crystal aligning agent), in order to reduce the residual DC accumulation and accelerate the charge relaxation while maintaining the electrical characteristics such as the voltage holding ratio. For the purpose of improving the liquid crystal alignment property, it is preferably less than 50 mol%, more preferably 46 mol% or less, still more preferably 44 mol% or less, still more preferably 42 mol% or less, still more preferably 38 mol% or less, still more preferably 36 mol% or less, still more preferably 34 mol% or less, still more preferably 32 mol% or less, still more preferably 30 mol% or less, still more preferably 28 mol% or less, still more preferably 26 mol% or less, still more preferably 24 mol% or less, still more preferably 22 mol% or less.

In the case where one of the polymers is included, the proportion of the compounds represented by the formulas (1) to (3) (in the case where two or more types are included, the total thereof) is preferably more than 50 mol%, more preferably 54 mol%, still more preferably 60 mol%, still more preferably more than 60 mol%, still more preferably 65 mol%, still more preferably 66 mol% or more, still more preferably 67 mol%, still more preferably 68 mol% or more, yet more preferably 69 mol% or more, and still more preferably 70 mol% or more, with respect to the total amount of diamine used, in order to suppress the pretilt angle of the liquid crystal to be low, with respect to the total amount of diamine used for synthesizing the polymer. The content is preferably 99 mol% or less, 98 mol% or less, 96 mol% or less, 94 mol% or less, 90 mol% or less, or less than 90 mol%. In the formula (1), when m is 8, it is preferably 100 mol%, and when it is 100 mol%, the pretilt angle can be remarkably reduced.

In the present embodiment (in the case where one of the polymers is included), the proportion of the compounds represented by the formulae (a) to (C) (in the case where two or more types are included, the total thereof) is preferably 0.5 mol% or more, more preferably 0.8 mol% or more, still more preferably 1 mol% or more, and may be 4 mol% or more, or 6 mol% or more, with respect to the total amount of diamine used. In the present embodiment (including one of the polymers), the proportion of the compounds represented by the formulas (a) to (C) (in the case where two or more types are included, the total) is preferably less than 50 mol%, more preferably 46 mol% or less, still more preferably 44 mol% or less, still more preferably 42 mol% or less, still more preferably 40 mol% or less, still more preferably 38 mol% or less, still more preferably 36 mol% or less, still more preferably 34 mol% or less, still more preferably 32 mol% or less, still more preferably 30 mol% or less, still more preferably 28 mol% or less, still more preferably 26 mol% or less, still more preferably 24 mol% or less, still more preferably 22 mol% or less, based on the total amount of diamine used, for the purpose of improving the liquid crystal alignment property. In order to reduce the pretilt angle, the amount of the compounds represented by the formulas (B-3) (for example, k=2), (B-5), (B-8), and (C-1) to (C-3) is preferably 40 mol% or less, more preferably less than 40 mol%, still more preferably 30 mol% or less, and still more preferably less than 30 mol%. In particular, the amount of the compounds represented by the formulas (C-1) to (C-3) is preferably 10 mol% or less, more preferably less than 10 mol%.

Therefore, in the present embodiment (in the case where one type of the polymer is included), the proportion of the compounds represented by the formulae (1) to (3) (in the case where two or more types are included, the total thereof) is 70 mol% or more with respect to the total amount of diamine used, and the proportion of the compounds represented by the formulae (a) to (C) is 1 mol% to 30 mol% with respect to the total amount of diamine used.

In the present embodiment, when the compound represented by the formula (D) is used, the amount of the compound represented by the formula (D) used is not particularly limited, and may be 10 mol% or more, 20 mol% or more, or 30 mol% or more based on the total amount of the tetracarboxylic dianhydride used for the polymer synthesis, in order to reduce the residual DC accumulation and further accelerate the charge relaxation while maintaining the electrical characteristics such as the alignment voltage holding ratio. Further, it is preferably 60 mol% or less, more preferably 50 mol% or less.

The liquid crystal aligning agent of the present invention preferably contains at least two polymers of polymer (P) and polymer (Q). Thus, at least two of the polymers are contained, the at least two polymers comprising polymer (P) and polymer (Q); the raw material for synthesizing the polymer (P) contains at least one selected from the group of compounds represented by the formulas (1) to (3); the raw material for synthesizing the polymer (Q) includes at least one selected from the group of compounds represented by the formulas (a) to (C) and the compound represented by the formula (D).

In the liquid crystal aligning agent containing the polymer (P) and the polymer (Q), the amount of the compound represented by the formulas (1) to (3) as a raw material for synthesizing the polymer (P) (in the case of containing two or more types, the total amount thereof) is preferably more than 50 mol%, more preferably 54 mol%, further preferably 56 mol%, further preferably 60 mol%, further more preferably 70 mol%, further more preferably 75 mol%, further more preferably 80 mol%, further more preferably 82 mol%, further more preferably 84 mol%, further more preferably 85 mol%, further more preferably 86 mol%, further more preferably 87 mol%, further more preferably 88 mol%, further more preferably 89 mol%, further more preferably 90 mol%, with respect to the total amount of diamines used for synthesizing the polymer (P), in order to suppress the pretilt angle of the liquid crystal to a low level. Here, when the compound represented by the formula (1-4) is used as a raw material for synthesizing the polymer (P), and the compound represented by the formula (E-5) which is considered as a compound for increasing the surface energy is used as a raw material for synthesizing the polymer (Q), it is also preferable to reduce the amount of the compound represented by the formula (1-4) used in the polymer (P). The upper limit is not particularly limited, and may be 100 mol% or less, 95 mol% or less, 85 mol% or less, or 75 mol% or less. In addition, the amount of the compound represented by the formulas (a) to (C) used for the synthetic polymer (Q) (in the case where two or more types are included, the total amount is preferably more than 0 mol%, more preferably more than 5 mol%, still more preferably more than 10 mol%, still more preferably more than 20 mol%, still more preferably more than 25 mol%, still more preferably more than 30 mol% with respect to the total amount of diamine used for the synthetic polymer, in order to reduce the accumulation of residual DC and further accelerate the charge relaxation while maintaining the electrical characteristics such as the voltage holding ratio. In order to maintain the liquid crystal alignment, the amount is preferably 60 mol% or less, more preferably 55 mol% or less, and still more preferably 50 mol% or less. In order to reduce the pretilt angle, the amount of the compounds represented by the formulas (B-3) (for example, k=2), (B-5), (B-8) and (C-1) to (C-3) is preferably 30 mol% or less, more preferably less than 30 mol%. The amount of the compound represented by the formulas (a) to (C) used for synthesizing the polymer (Q) is preferably 10 to 50 mol%, more preferably 30 to 50 mol%.

In order to reduce the accumulation of residual DC and further accelerate the relaxation of charges while maintaining the electrical characteristics such as voltage holding ratio, the amount of the compound represented by the formula (D) to be used is preferably 20 to 50% by mol, more preferably 20 to 30% by mol, based on the total amount of tetracarboxylic dianhydride used for synthesizing the polymer (Q).

In the embodiment of the present invention, therefore, the proportion of the compound represented by the formulae (1) to (3) in the polymer (P) is 70 mol% or more relative to the total amount of diamine used; in the polymer (Q), the proportion of the compound represented by the formula (a) to the formula (C) is 10 mol% to 50 mol% based on the total amount of diamine used.

In the polymer (P), the proportion of the compound represented by the formulae (1) to (3) is 90 mol% or more relative to the total amount of diamine used; in the polymer (Q), the proportion of the compound represented by the formula (a) to the formula (C) is 30 to 50 mol% based on the total amount of diamine used. In the embodiment of the present invention, in the polymer (P), the proportion of the compound represented by the formulae (1) to (3) is 70 mol% or more, preferably 90 mol% or more, based on the total amount of diamine used; in the polymer (Q), the proportion of the compound represented by the formula (D) is 20 to 50 mol% based on the total amount of tetracarboxylic dianhydride used.

In the present invention, as a raw material for synthesizing a polymer, a known tetracarboxylic dianhydride (including a derivative thereof) and a diamine (including dihydrazide) can be further used.

The tetracarboxylic dianhydride used in the present invention may be selected from known tetracarboxylic dianhydrides without limitation. The known tetracarboxylic dianhydrides may be any of aromatic systems (including heteroaromatic systems) in which dicarboxylic anhydrides are directly bonded to aromatic rings, and aliphatic systems (including heterocyclic systems) in which dicarboxylic anhydrides are not directly bonded to aromatic rings. For example, a tetracarboxylic dianhydride disclosed in Japanese patent application laid-open No. 2016-029447 or Japanese patent application laid-open No. 2016-041683 can be used. Preferred examples are shown below.

[ chemical 19]

In the formula (AN-2) and the formula (AN-8), m is independently AN integer of 1 to 12.

Preferred materials for improving the respective characteristics of the tetracarboxylic dianhydride will be described.

In the case where importance is attached to improving the alignment property of the liquid crystal, the compounds represented by the formulas (AN-2), (AN-7) and (AN-8) are preferable.

In order to enhance the transmittance of the liquid crystal display element, the formulae (AN-1), (AN-5), (AN-4), (AN-11), (AN-12), (AN-13), (AN-14), (AN-17) and (AN-18) are preferable.

In the case where improvement of VHR (voltage holding ratio) of the liquid crystal display element is important, the formulas (AN-1), (AN-4), (AN-5), (AN-11), (AN-13), (AN-14), (AN-16), (AN-17) and (AN-18) are preferable.

The improvement of the relaxation rate of the residual charge (residual DC) in the alignment film by reducing the volume resistance value of the liquid crystal alignment film is effective as one of methods for preventing burn-in. In the case where the above object is emphasized, the formula (AN-3), the formula (AN-6), the formula (AN-7), the formula (AN-9), the formula (AN-10), the formula (AN-11) and the formula (AN-15) are preferable.

In the present application, it is considered that by using tetracarboxylic dianhydride having nitrogen (especially, secondary amino group, tertiary amino group) or nitrogen-containing heterocycle (for example, formula (AN-3) or the formula (AN-11)) as a raw material for synthesizing a polymer, the accumulation of residual DC can be further reduced and the relaxation rate can be improved. The amount of the tetracarboxylic dianhydride used for synthesizing the polymer is preferably 1 to 40 mol%, more preferably 1 to 15 mol%, and still more preferably 1 to 10 mol%.

In the embodiment of the present application, it is preferable that at least one selected from the group consisting of the compounds represented by the formulas (1) to (3) and at least one selected from the group consisting of the compounds represented by the formulas (a) to (C) are used in combination. In this embodiment, if the tetracarboxylic dianhydride is a combination of two or more types, there is a concern that the liquid crystal alignment property will be deteriorated. Here, suitable examples of the three or more specific combinations may be, in addition to the combinations disclosed in the embodiments of the present application: (AN-2), (AN-4) and (AN-6); (AN-4), (AN-7) and (AN-9); (AN-4), (AN-6), and (AN-11). By such a combination, the desired effect of the present application can be effectively exerted.

In the embodiment of the present invention, the acid dianhydride is preferably represented by the formula (AN-8). In the case of combining the formula (1-1) with the formula (B), the acid dianhydride is preferably the formula (AN-8). According to the embodiment, there are the following effects: the pretilt angle is reduced, the accumulation of residual DC is reduced, the relaxation speed is increased, and the liquid crystal orientation is further improved. In the embodiment of the present invention, when the compound represented by the formula (1-1) and the compound represented by the formula (B) are combined and the proportion of the compound represented by the formula (1-1) is 90 mol% or more relative to the total amount of diamine used, it is particularly preferable to use the formula (AN-8) as the acid dianhydride. According to the embodiment, there are the following effects: the pretilt angle is reduced, the accumulation of residual DC is reduced, the relaxation speed is increased, and the liquid crystal orientation is further improved.

In the present invention, in a form containing at least two polymers of the polymer (P) and the polymer (Q), at least one selected from the compounds represented by the above formula (D) may be used as a raw material for the polymer (P).

The compound used for the polymer (P) is preferably a compound of the formula (AN-1), the formula (AN-3), the formula (AN-4), the formula (AN-6), the formula (AN-8) or the formula (AN-9), and in the formula (AN-8), m=4 or 8 is more preferable. In order to exhibit a high characteristic in good balance among the electric characteristics such as liquid crystal alignment and voltage holding ratio, the expression (AN-4), the expression (AN-6), and the expression (AN-8) are preferably used in combination, and in the expression (AN-8), m=4 or 8 is more preferably used.

The diamine (including dihydrazide) used in the present invention may be selected from known diamines and dihydrazides without limitation. For example, a diamine or dihydrazide disclosed in Japanese patent application laid-open No. 2016-029447 or Japanese patent application laid-open No. 2016-041683 can be used. Preferred examples are shown below.

[ chemical 20]

[ chemical 21]

In the formula (DI-3), the formula (DI-6) and the formula (DI-7), m is an integer of 1 to 12.

In an embodiment of the present invention, at least one compound selected from the group consisting of compounds represented by the following formula (E) is further included as a raw material for synthesizing the polymer.

[ chemical 22]

H ₂ N-W ⁵ -W ⁴ -W ⁵ -NH ₂ (E)

In the formula (E), W ⁴ Is an alkylene group having 1 to 6 carbon atoms, a 1, 3-phenylene group, or a 1, 4-phenylene group; and W is ⁵ Independently is a single bond, -NHCO-, or-CONH-. In particular, in the two-layer (mixed system) configuration, phase separation can be effectively caused by containing the compound represented by the formula (E). In an embodiment of the present invention, at least one selected from the compounds represented by the formula (E) is contained as a raw material used for the synthesis of the polymer (Q).

[ chemical 23]

H ₂ N-W ⁵ -W ⁴ -W ⁵ -NH ₂ (E)

In the formula (E), W ⁴ Is an alkylene group having 1 to 6 carbon atoms, a 1, 3-phenylene group, or a 1, 4-phenylene group, and W ⁵ Independently is a single bond, -NHCO-, or-CONH-.

The compounds represented by the formula (E) are exemplified by the following formulas (E-1) to (E-8). That is, the compound represented by the formula (E) is at least one compound selected from the group consisting of the compounds represented by the following formulas (E-1) to (E-8).

[ chemical 24]

In the formula (E-5) and the formula (E-8), p is an integer of 1 to 6, respectively.

In an embodiment of the present invention, the compound represented by the formula (1) to the formula (3) is at least one selected from the group consisting of the compounds represented by the formula (1-1) to the formula (1-4), the formula (2-1), the formula (2-2) and the formula (3-1); the compound represented by the formula (A) to the formula (C) is at least one selected from the group of the compounds represented by the formula (A-12), the formula (A-14), the formula (A-15), the formula (A-16), the formula (A-17), the formula (B-3), the formula (C-2) and the formula (C-3); the compound represented by the formula (D) is at least one selected from the group of the compounds represented by the formula (D-2) and the formula (D-3); the compound represented by the formula (E) is at least one selected from the group of compounds represented by the formulas (E-5) to (E-7). In an embodiment of the present invention, the compound represented by the formula (1) to the formula (3) is at least one selected from the formulas (1-1) and (1-4); the compound represented by the formula (A) to the formula (C) is at least one selected from the formula (A-15) and the formula (B-3); the compound represented by the formula (D) is a compound represented by the formula (D-2); the compound represented by the formula (E) is a compound represented by the formula (E-5).

Preferred materials for improving each characteristic of the diamine (including dihydrazide) are described.

In order to further enhance the alignment of the liquid crystal, the diamine (including dihydrazide) is preferably represented by the formulas (DI-3), (DI-6), (DI-7), (DI-9), (DI-10), (E-1) and (E-8). More preferably, formula (DI-3), formula (DI-6), formula (DI-7), and formula (E-1). In the formula (DI-3), m=1, 2, 4 or 6 is preferable, and m=2, 4 is more preferable. In the formula (DI-6), m=2 to 6 is preferable, and m=2 or 5 is more preferable. In the formula (DI-7), m=1 or 2 is preferable, and m=1 is more preferable. The diamine may be used alone or in combination of two or more.

In the case where importance is attached to the improvement of the transmittance, the diamine (including dihydrazide) is preferably represented by the formulas (DI-1), (DI-3), (DI-8) and (E-8), more preferably (DI-1). In the formula (DI-3), m=1, 2, 4 or 6 is preferable, and m=1 or 2 is more preferable.

In the case where importance is attached to improving VHR of a liquid crystal display element, the diamine (including dihydrazide) is preferably represented by the formulas (DI-1), DI-3, E-1, and E-2), more preferably by the formulas (DI-1) and (DI-3). In the formula (DI-3), m=1 is preferable.

The improvement of the relaxation rate of the residual charge (residual DC) in the liquid crystal alignment film by reducing the volume resistance value of the liquid crystal alignment film is effective as one of methods for preventing burn-in. In order to address the above-mentioned object, the diamine (including dihydrazide) is preferably represented by the formulas (DI-3), (DI-6), (DI-7), and (E-1) to (E-6), more preferably represented by the formulas (DI-3), (DI-7), and (E-1), (E-5), and (E-6). In the formula (DI-3), m=1, 2, 4 or 6 is preferable, and m=1 or 2 is more preferable. In the formula (DI-6), m=2 to 6 is preferable, and m=2 or 5 is more preferable. In the formula (DI-7), m=1 or 2 is preferable, and m=1 is more preferable. In the formula (E-5), p=4 is preferable.

In the embodiment of the present invention, at least one selected from the compounds represented by the above formulas (a) to (C) may be used as a raw material for the polymer (P) or at least one selected from the compounds represented by the formulas (1) to (3) may be used as a raw material for the polymer (Q) in the liquid crystal aligning agent comprising the polymer (P) and the polymer (Q). In this embodiment, the nitrogen-containing heterocycle is preferably a cycloalkane containing nitrogen, and for example, the heterocycle is preferably a cycloalkane containing nitrogen of the formula (A-15), the heterocycle is preferably a cycloalkane containing nitrogen of the formula (A-16), the heterocycle is preferably a cycloalkane containing nitrogen of the formula (A-17), and the heterocycle is preferably a cycloalkane containing nitrogen of the formula (A-17).

As the compound used in the polymer (P), the compounds of the formula (DI-3), the formula (DI-5), the formula (A-15) and the formula (C-3) are preferable. Here, in the formula (DI-3), m=1 or 4 is preferable, and 1 is more preferable. The compound used for the polymer (Q) is preferably at least one compound selected from the group consisting of the compounds represented by the formula (DI-3), the formula (DI-5), the formula (DI-6), the formula (DI-9) and the formula (E). Here, in the formula (DI-3), m=1, 2 or 4 is preferable, and 1 or 2 is more preferable. Here, in the formula (DI-6), m=2 or 5 is preferable, and 2 is more preferable.

In the embodiment of the present invention, in order to suppress the pretilt angle of the liquid crystal to be lower and reduce the accumulation of the residual DC and accelerate the relaxation, it is important that the polymer (P) serving to suppress the pretilt angle of the liquid crystal to be lower is segregated in the upper layer (liquid crystal layer side), and the polymer (Q) serving to serve as a liquid crystal display element which has a small accumulation of the residual DC and a rapid relaxation of the electric charge is segregated in the lower layer (substrate side). It is believed that the two polymers segregate more easily by using a surface energy increasing compound in polymer (Q). Accordingly, in an embodiment of the present invention, a liquid crystal alignment film for aligning a liquid crystal layer includes a coating film derived from a liquid crystal alignment agent on a substrate, the coating film including a polymer (P) and a polymer (Q), the polymer (P) being located on a liquid crystal layer side, and the polymer (Q) being located on a substrate side.

In the embodiment of the present invention, as the raw material used for the polymer (Q), a compound represented by the formula (E) which is considered to be a compound that increases the surface energy is preferably used. Specific compounds are preferably represented by the formulas (E-1) to (E-8), more preferably by the formulas (E-1), E-3, E-4), E-5 and E-6, still more preferably by the formulas (E-3), E-4, E-5 and E-6, still more preferably by the formulas (E-5), (E-6) and still more preferably by the formulas (E-5), and in the formulas (E-5), p=4 is preferable. In the embodiment of the present invention, the amount of the compound represented by the formula (E) for synthesizing the polymer (Q) is preferably 50 to 70 mol% based on the total amount of diamine for synthesizing the polymer (Q). Therefore, in the polymer (Q), the proportion of the compound represented by the formula (E) is 50 to 70 mol% relative to the total amount of diamine used.

In the embodiment of the present invention, the diamine may be partially substituted with monoamine in such a manner that the diamine has a monoamine content of 40 mol% or less with respect to the diamine. By such substitution, termination (termination) of polymerization reaction at the time of formation of a polymer (e.g., polyamic acid) can be caused, and progress of polymerization reaction above can be suppressed. Further, the weight average molecular weight (hereinafter also referred to as Mw) of the obtained polymer (e.g., polyamic acid ester, or polyimide) can be easily controlled, and for example, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. The diamine substituted with monoamine may be one kind or two or more kinds if the effect of the present invention is not impaired. Examples of the monoamine include: aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, and n-eicosylamine.

In an embodiment of the present invention, the polymer may further contain a monoisocyanate compound in its raw material. By including a monoisocyanate compound in the raw material, the end of the obtained polymer (for example, polyamic acid (including a derivative thereof)) is modified, and Mw is adjusted. By using the end-modified polymer (for example, polyamic acid (including a derivative thereof)), for example, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. From the above viewpoint, the content of the monoisocyanate compound in the raw material is preferably 1 to 10 mol% relative to the total amount of diamine and tetracarboxylic dianhydride in the raw material. Examples of the monoisocyanate compound include: phenyl isocyanate, and naphthyl isocyanate.

In an embodiment of the invention, the polymer may be obtained by: a mixture of tetracarboxylic dianhydride and diamine is reacted in an organic solvent. In the synthesis reaction, the conditions in the synthesis of a general polymer (for example, polyamic acid) can be directly applied without particular conditions other than the selection of the raw materials. The solvents that can be used will be described later.

In the embodiment of the present invention, the liquid crystal aligning agent may further contain other components than the polymer. The other components may be one kind or two or more kinds. Examples of the other component include other polymers and compounds described below.

As other polymers, there may be mentioned: the polyamide acid, polyamide acid ester, or polyimide other than the polymer (P) and the polymer (Q) (hereinafter, referred to as "other polyamide acid or its derivative"), polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, or the like. These may be one kind or two or more kinds. Among these, other polyamic acids or derivatives thereof and polysiloxanes are preferable, and other polyamic acids or derivatives thereof are more preferable.

The diamine used for synthesizing the other polyamic acid or derivative thereof preferably contains 30 mol% or more of an aromatic diamine, and more preferably 50 mol% or more of the entire diamine.

Other polyamic acids or derivatives thereof can be synthesized by the methods described below according to the method for synthesizing polyamic acid or derivatives thereof, which is an essential component of the liquid crystal aligning agent of the present invention.

As described above, one of preferred embodiments of the liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing at least two polymers of polymer (P) and polymer (Q). In the formation of a coating film (particularly, a film) using a liquid crystal aligning agent containing two polymers, there is known a phenomenon in which a polymer having small surface energy is separated from an upper layer and a polymer having large surface energy is separated from a lower layer. In the present invention, a polymer (P) serving to suppress the pretilt angle of liquid crystal to a low level is segregated in an upper layer, and a polymer (Q) serving to provide a liquid crystal display element having a small residual DC accumulation and a fast charge relaxation is segregated in a lower layer, whereby a liquid crystal alignment film exhibiting both of the above-described characteristics can be formed. In an embodiment of the present invention, the surface energy of at least two polymers of the polymer (P) and the polymer (Q) are different from each other, and the surface energy of the polymer (Q) is larger than the surface energy of the polymer (P).

The confirmation of whether or not the liquid crystal alignment film is subjected to layer separation can be performed, for example, by measuring the surface energy of the film formed and confirming the surface energy of the film formed of the liquid crystal alignment agent containing only the polymer (P) to be the same value as or close to the surface energy of the film formed of the liquid crystal alignment agent containing only the polymer (P).

As described above, in order to exhibit good liquid crystal alignment and low pretilt angle characteristics, the content of the polymer (P) in the liquid crystal aligning agent of the present invention is preferably 20 wt% or more, and more preferably 30 wt% or more, based on 100 wt% of the total amount of the polymers contained. Further, the content is preferably 80% by weight or less, more preferably 70% by weight or less. Among them, the preferable content of the polymer (P) described herein is a criterion, and sometimes varies depending on the combination of tetracarboxylic dianhydride or diamine used in the raw material.

In the embodiment containing one of the polymers, the Mw of the polymer is preferably 20,000 ～ 160,000, more preferably 40,000 ～ 80,000, and further preferably 45,000 ～ 70,000. In at least two polymers of the polymer (P) and the polymer (Q), mw is also independently preferably 20,000 ～ 160,000, more preferably 40,000 ～ 80,000. The Mw of the polymer can be determined by the methods described in the examples. The Mw of the polymer can be adjusted, for example, by the time for which the tetracarboxylic dianhydride is reacted with the diamine. The Mw of the polymer contained in the reaction liquid can be determined by measuring the reaction liquid by gel permeation chromatography (gelpermeation chromatography, GPC) while taking a small amount of the reaction liquid in the polymerization reaction, and the end point of the reaction can be determined from the measured value. In addition, a method of controlling Mw by substituting a significant amount of tetracarboxylic dianhydride and diamine with monocarboxylic acid or monoamine to cause a polymerization reaction at the end of the reaction is also known.

The polysiloxane may further include polysiloxanes disclosed in Japanese patent application laid-open No. 2009-036966, japanese patent application laid-open No. 2010-185001, japanese patent application laid-open No. 2011-102963, japanese patent application laid-open No. 2011-253175, japanese patent application laid-open No. 2012-159525, international publication No. 2008/044644, international publication No. 2009/148099, international publication No. 2010/074261, international publication No. 2010/074264, international publication No. 2010/126108, international publication No. 2011/068123, international publication No. 201I/068127, international publication No. 2011/068128, international publication No. 2012/115157, international publication No. 2012/165354, and the like.

In an embodiment of the present invention, at least one selected from the group consisting of an alkenyl-substituted nadimide (nadimide) compound, a compound having a radical-polymerizable unsaturated double bond, an oxazine compound, an oxazoline compound, and an epoxy compound is further contained.

< alkenyl substituted Nadick imide Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an alkenyl-substituted nadic imide compound for the purpose of stabilizing the electric characteristics of the liquid crystal display element for a long period of time. The alkenyl-substituted nadic imide compound may be used singly or in combination. For the purpose, the content of the alkenyl-substituted nadic imide compound is preferably 1 to 100% by weight, more preferably 1 to 70% by weight, and still more preferably 1 to 50% by weight, relative to the polymer (for example, polyamic acid (including its derivative)).

The alkenyl-substituted nadic imide compound is preferably a compound that is soluble in a solvent in which the polymer used in the present invention, for example, polyamic acid (including derivatives thereof), is dissolved. Examples of such alkenyl-substituted nadic imide compounds include those disclosed in Japanese patent application laid-open No. 2013-242526. Preferred alkenyl-substituted nadic imide compounds include: bis {4- (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide) phenyl } methane, N '-m-xylylene-bis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide), N' -hexamethylenebis (allylbicyclo [2.2.1] hept-5-ene-2, 3-dicarboxyimide).

< Compound having radically polymerizable unsaturated double bond >

For example, the liquid crystal aligning agent of the present invention may further contain a compound having a radical polymerizable unsaturated double bond for the purpose of stabilizing the electrical characteristics of the liquid crystal display element for a long period of time. The compound having a radical polymerizable unsaturated double bond may be one compound or two or more compounds. The compound having a radical polymerizable unsaturated double bond does not contain an alkenyl-substituted nadic imide compound. For the purpose, the content of the compound having a radically polymerizable unsaturated double bond is preferably 1 to 100% by weight, more preferably 1 to 70% by weight, and still more preferably 1 to 50% by weight relative to the polymer (for example, polyamic acid (including its derivative)).

The ratio of the compound having a radically polymerizable unsaturated double bond to the alkenyl-substituted nadir imide compound is preferably 0.1 to 10, more preferably 0.5 to 5 in terms of weight ratio, in order to reduce the ion density of the liquid crystal display element, suppress the increase in the ion density with time, and further suppress the occurrence of an afterimage.

Examples of preferred compounds having a radically polymerizable unsaturated double bond include compounds having a radically polymerizable unsaturated double bond disclosed in Japanese patent application laid-open No. 2013-242526 and the like.

< oxazine Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an oxazine compound for the purpose of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time. The oxazine compound may be one compound or two or more compounds. For the purpose, the content of the oxazine compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and still more preferably 1 to 20% by weight, relative to the polymer (for example, polyamic acid (including its derivative)).

The oxazine compound is preferably an oxazine compound which is soluble in an organic solvent in which a polymer (for example, polyamic acid (including a derivative thereof)) is dissolved and has ring-opening polymerization property. Preferable examples of the oxazine compound include oxazine compounds represented by the formula (OX-3-1) and the formula (OX-3-9), and oxazine compounds disclosed in japanese patent application laid-open No. 2013-242526 and the like.

[ chemical 25]

< oxazoline Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one compound or two or more compounds. For the purpose, the content of the oxazoline compound is preferably 0.1 to 50 wt%, more preferably 1 to 40 wt%, and still more preferably 1 to 20 wt% with respect to the polymer (for example, polyamic acid (including derivatives thereof)). For the purpose described above, the content of the oxazoline compound is preferably 0.1 to 40% by weight relative to the polymer (for example, polyamide acid (including derivatives thereof)) when the oxazoline structure in the oxazoline compound is converted to oxazoline.

As the oxazoline compound, for example, an oxazoline compound disclosed in japanese patent application laid-open publication No. 2013-242526 or the like is cited. As a preferred oxazoline compound, 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene is exemplified.

< epoxy Compound >

For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical characteristics in the liquid crystal display element for a long period of time. The epoxy compound may be one kind of compound or two or more kinds of compounds. For the purpose, the content of the epoxy compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and still more preferably 1 to 20% by weight, relative to the polymer (for example, polyamic acid (including derivatives thereof)).

Examples of the epoxy compound include those disclosed in Japanese patent application laid-open No. 2013-242526. Preferable epoxy compounds include: n, N '-tetraglycidyl-4, 4' -diaminodiphenylmethane, 3-glycidoxypropyl trimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyl triethoxysilane, (3, 3', 4' -diepoxy) dicyclohexyl.

In addition, for example, the liquid crystal aligning agent of the present invention may further contain various additives. Examples of the various additives include a high molecular compound and a low molecular compound other than a polymer (for example, polyamide acid (including a derivative thereof)), and the additives may be selected and used for various purposes. The inclusion of the additive has the technical effect of improving the hardness of the film, particularly improving the resistance to the rubbing treatment, and further improving the reliability as an alignment film. If the additive is added, the pretilt angle tends to be increased, but in the embodiment of the present invention, even if the additive is added, there is an effect that the pretilt angle can be intentionally reduced.

For example, the polymer compound may be a polymer compound that is soluble in an organic solvent. From the viewpoint of controlling the electric characteristics and alignment properties of the formed liquid crystal alignment film, it is preferable to add such a polymer compound to the liquid crystal alignment agent of the present invention. Examples of the polymer compound include: polyamides, polyurethanes, polyureas, polyesters, polyepoxides, polyester polyols, silicone-modified polyurethanes, and silicone-modified polyesters.

In addition, as the low molecular compound, for example, 1) when improvement of coatability is desired, a surfactant satisfying the object is exemplified; 2) When improvement of antistatic property is required, antistatic agents are exemplified; 3) When improvement of adhesion to a substrate is desired, a silane coupling agent or a titanium coupling agent is exemplified; in addition, in the case of 4) imidization at a low temperature, an imidization catalyst is exemplified.

Examples of the silane coupling agent include those disclosed in Japanese patent application laid-open No. 2013-242526. As a preferred silane coupling agent, 3-aminopropyl triethoxysilane is exemplified. Further, as the imidization catalyst, imidization catalysts disclosed in Japanese patent application laid-open No. 2013-242526 and the like are exemplified.

The amount of the silane coupling agent to be added is usually 0 to 20% by weight, preferably 0.1 to 10% by weight based on the total weight of the polymer (e.g., polyamic acid (including its derivative)).

The amount of the imidization catalyst to be added is usually 0.01 to 5 equivalents, preferably 0.05 to 3 equivalents, relative to the carbonyl group of the polymer (for example, polyamic acid (including its derivative)).

The amount of other additives to be added varies depending on the use thereof, and is usually 0 to 100% by weight, preferably 0.1 to 50% by weight, based on the total weight of the polymer (e.g., polyamic acid (including derivatives thereof)).

In addition, for example, the liquid crystal aligning agent of the present invention may further contain a solvent in terms of coatability of the liquid crystal aligning agent or adjustment of the concentration of the polymer (for example, polyamic acid (including derivatives thereof)). The solvent is not particularly limited as long as it is a solvent having an ability to dissolve the polymer component. The solvent may be widely used in terms of the production steps or uses of the polymer component (e.g., polyamic acid, soluble polyimide, etc.) and may be appropriately selected depending on the purpose of use. The solvent may be one kind or a mixed solvent of two or more kinds.

Examples of the solvent include a lipophilic solvent of the polymer (for example, polyamic acid (including a derivative thereof)), and other solvents for improving coatability.

As the aprotic polar organic solvent which is a solvent-philic with respect to the polymer (for example, polyamic acid (including its derivative)), there can be mentioned: lactones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylimidazolidinone, N-methylcaprolactam, N-methylpropanamide, N-dimethylacetamide, dimethylsulfoxide, N-dimethylformamide, N-diethylformamide, N-diethylacetamide, and γ -butyrolactone.

Examples of other solvents for the purpose of improving coatability and the like include: alkyl lactate, 3-methyl-3-methoxybutanol, tetrahydronaphthalene, isophorone, phenylacetate, ethylene glycol monoalkyl ether such as ethylene glycol monobutyl ether, diethylene glycol monoalkyl ether such as diethylene glycol monoethyl ether, triethylene glycol monoalkyl ether, propylene glycol monomethyl ether such as propylene glycol monobutyl ether, dialkyl malonate such as diethyl malonate, dipropylene glycol monoalkyl ether such as dipropylene glycol monomethyl ether, ester compounds such as acetate, and ketone compounds such as diisobutyl ketone.

Of these, the solvent is particularly preferably N-methyl-2-pyrrolidone, dimethylimidazolidone, gamma-butyrolactone, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and diisobutyl ketone.

The concentration of the polymer (e.g., polyamic acid) in the liquid crystal aligning agent of the present invention is preferably 0.1 to 40% by weight, more preferably 1 to 20% by weight, and still more preferably 1.5 to 8% by weight. In the case of applying the alignment agent to a substrate, there is a case where an operation of diluting a polymer (for example, polyamic acid) contained in the alignment agent with a solvent in advance is required in order to adjust the film thickness.

The preferable range of the viscosity of the liquid crystal aligning agent of the present application varies depending on the method of coating, the concentration of the polymer (e.g., polyamic acid (including its derivative)), the kind of polymer (e.g., polyamic acid (including its derivative)) used, the kind and ratio of the solvent. For example, in the case of coating by a printer, a range of 5mpa·s to 100mpa·s is preferable because a sufficient film thickness can be obtained and printing unevenness can be prevented from becoming large, and thus 10mpa·s to 80mpa·s is more preferable. In the case of coating by spin coating, it is preferable that 5 to 200 mPas (more preferably 10 to 100 mPas). When the coating is performed using an inkjet coating apparatus, it is preferably 5 to 50mpa·s (more preferably 5 to 20mpa·s). The viscosity of the liquid crystal aligning agent is measured by a rotational viscosity measurement method, for example, using a rotational viscometer (TVE-20L type manufactured by Dong machine industry) (measurement temperature: 25 ℃ C.). In the examples of the present application, the ratio was about 5 mPas to 15 mPas.

< liquid Crystal alignment film >

According to an embodiment of the present application, there is provided a liquid crystal alignment film formed from the liquid crystal alignment agent. The following is a detailed description. In an embodiment of the present application, the liquid crystal alignment film is a film formed by heating a coating film of the liquid crystal alignment agent. The liquid crystal alignment film of the present application can be obtained by a usual method for producing a liquid crystal alignment film from a liquid crystal alignment agent. For example, the liquid crystal alignment film of the present application can be obtained by passing through the following steps: a step of forming a coating film of the liquid crystal aligning agent of the present application, a step of performing heat drying, and a step of performing heat calcination. The liquid crystal alignment film of the present application may be given anisotropy by subjecting the film obtained by the heat drying step and the heat calcining step to rubbing treatment as described later, if necessary. Alternatively, the anisotropy may be imparted by irradiating light after the coating step, the heat drying step, or the heat calcining step, as necessary.

The coating film can be formed by applying the liquid crystal aligning agent of the present application to a substrate in a liquid crystal display element in the same manner as in the production of a usual liquid crystal alignment film. The substrate may be: indium Tin Oxide (ITO), indium zinc Oxide (Indium Zinc Oxide, IZO) (In ₂ O ₃ -ZnO), indium gallium zinc oxide (Indium Gallium Zinc Oxide, IGZO) (In-Ga-ZnO) ₄ ) Electrodes such as electrodes, and substrates such as glass, silicon nitride, acrylic, polycarbonate, polyimide, and the like for color filters. Furthermore, ITO is used in embodiments of the present application.

As a method of applying a liquid crystal aligning agent to a substrate, a rotator method, a printing method, a dipping method, a dropping method, an inkjet method, and the like are generally known. These methods can be applied equally well in the present application.

As the above-mentioned heat drying step (precalcination step), a method of performing heat treatment in an oven or an infrared oven, a method of performing heat treatment on a hot plate, and the like are generally known. The heat drying step is preferably carried out at a temperature within a range where the solvent can evaporate, more preferably at a relatively low temperature relative to the temperature in the heat calcining step. Specifically, the heating and drying temperature is preferably in the range of 30 to 150 ℃, and more preferably in the range of 50 to 120 ℃. The time is not particularly limited, and is, for example, preferably 1 to 10 minutes, and more preferably 1 to 5 minutes.

The heating and calcining step may be performed, for example, under conditions required for the polyamic acid or derivative thereof to exhibit dehydration and ring-closure reaction. As a method for calcining the coating film, a method of heat-treating in an oven or an infrared oven, a method of heat-treating on a hot plate, and the like are generally known. These methods can be applied equally well in the present invention. The temperature is usually preferably about 100 to 300 ℃, more preferably 120 to 280 ℃, and still more preferably 150 to 250 ℃. Further, the time is preferably 1 minute to 3 hours. In addition, the heating calcination may be performed at different temperatures multiple times. A plurality of heating devices set to different temperatures may be used, or 1 heating device may be used while sequentially changing to different temperatures. When the heating and calcining are performed 2 times at different temperatures, the 1 st time is preferably performed at a temperature of 90 to 180 ℃ and the 2 nd time is preferably performed at a temperature of 185 ℃ or higher. In addition, the temperature may be changed from a low temperature to a high temperature to perform calcination. In the case of calcining by changing the temperature, the initial temperature is preferably 90 to 180 ℃. The final temperature is preferably 185 to 300 ℃, more preferably 190 to 230 ℃.

In the method for forming a liquid crystal alignment film of the present invention, a known forming method such as a rubbing method or a photo-alignment method can be suitably used as a means for imparting anisotropy to an alignment film in order to align liquid crystal in one direction with respect to a horizontal and/or vertical direction. The friction cloth may be made of: cotton, rayon, nylon, and the like.

In the embodiment of the present invention using the rubbing method, the liquid crystal alignment film may be formed by the steps of: the method comprises a step of applying the liquid crystal aligning agent on a substrate, a step of heating and drying the substrate coated with the liquid crystal aligning agent to manufacture a film, a step of heating and calcining the film, and a step of rubbing the film after the heating and calcining.

The rubbing treatment may be carried out in the same manner as the rubbing treatment used in the usual alignment treatment of the liquid crystal alignment film, and in the liquid crystal alignment film of the present invention, the conditions for obtaining sufficient retardation (retardation) may be used. The preferable condition is Mao Yaru amount is 0.2 mm-0.8 mm. The stage moving speed is 5mm/sec to 250mm/sec. The rotation speed of the roller is 500rpm to 2,000rpm.

In the embodiment of the present invention, the liquid crystal alignment film can be suitably obtained by a method further including steps other than the above-described steps. For example, a step of cleaning the film produced by a cleaning liquid may be provided as part of the step for producing the liquid crystal alignment film. Of course, in the liquid crystal alignment film of the present invention, a step of cleaning the film after calcination or irradiation with radiation by a cleaning liquid is not necessary. In addition, other steps are not necessary, and a cleaning step may be provided as needed.

As a cleaning method using the cleaning liquid, there are: brushing (brushing), spray spraying (jet spray), steam cleaning, ultrasonic cleaning, or the like. These methods may be carried out alone or in combination. As the cleaning liquid, pure water (preferably ultrapure water), various alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene and xylene, halogen solvents such as methylene chloride (methylene chloride), ketones such as acetone and methyl ethyl ketone can be used, but the present invention is not limited thereto. Of course, these cleaning solutions are sufficiently purified cleaning solutions with few impurities. Such a cleaning method can also be applied to the cleaning step in the formation of the liquid crystal alignment film of the present invention.

In order to improve the liquid crystal aligning ability of the liquid crystal alignment film of the present invention, annealing treatment with heat or light may be used before and after the heating and calcining step and before and after the rubbing step. In the annealing treatment, the annealing temperature is 30 to 180 ℃, preferably 50 to 150 ℃, and the time is preferably 1 minute to 2 hours, more preferably 10 minutes to 1 hour. The annealing light used in the annealing treatment includes an Ultraviolet (UV) lamp, a fluorescent lamp, a light emitting diode (Light Emitting Diode, LED) lamp, and the like. The irradiation amount of light is preferably 0.3J/cm ² ～10J/cm ² 。

The film thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10nm to 300nm, more preferably 30nm to 150nm. The film thickness of the liquid crystal alignment film of the present invention can be measured by a known film thickness measuring device such as a level difference meter or ellipsometer (ellipsometer).

The liquid crystal alignment film of the present invention is characterized by having particularly large alignment anisotropy. The magnitude of such anisotropy can be evaluated by using polarized IR described in Japanese patent application laid-open No. 2005-275364 and the like. Further, as shown below, evaluation can also be performed by a method using ellipsometry (ellipsometry). Specifically, the retardation value of the liquid crystal alignment film can be measured by a spectroscopic ellipsometer. The retardation value of the film becomes larger in proportion to the degree of orientation of the polymer main chain. That is, those having a large retardation value have a large degree of orientation. Therefore, when the liquid crystal composition is used as a liquid crystal alignment film, the liquid crystal alignment film is considered to have a larger anisotropy, and thus the liquid crystal composition can be significantly restricted in alignment.

The liquid crystal alignment film of the present invention can be suitably used for a liquid crystal display element of a transverse electric field mode. In the case of a liquid crystal display element used in a transverse electric field mode, the smaller the pretilt (Pt) angle is, the higher the liquid crystal alignment capability is, the higher the black display level in a dark state is, and the higher the contrast is. The pretilt (Pt) angle is preferably 1.5 ° or less, more preferably 1.2 ° or less. Therefore, according to an embodiment of the present invention, the liquid crystal aligning agent can be used for manufacturing a transverse electric field type liquid crystal display element. In addition, according to an embodiment of the present invention, there is provided a transverse electric field type liquid crystal display element having the liquid crystal alignment film.

The liquid crystal alignment film of the present invention can be used for alignment control of a liquid crystal composition for a liquid crystal display such as a smart phone, an input panel, a vehicle monitor, a television, etc. In addition to the alignment application of the liquid crystal composition for liquid crystal display, the composition can be used for the alignment control of optical compensation materials or all other liquid crystal materials. In addition, the alignment film of the present invention has large anisotropy, and thus can be used alone for optical compensation material applications. In addition, according to an embodiment of the present invention, there is provided a liquid crystal display element having the liquid crystal alignment film.

< liquid Crystal display element >

The liquid crystal display element of the present invention will be described in detail. The present invention provides a liquid crystal display element, which comprises: the liquid crystal display device includes a pair of substrates disposed in opposition to each other, an electrode formed on one or both of surfaces of the pair of substrates in opposition to each other, a liquid crystal alignment film formed on the surfaces of the pair of substrates in opposition to each other, and a liquid crystal layer formed between the pair of substrates, wherein the liquid crystal alignment film is the alignment film of the present invention.

The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposited films. The electrode may be formed on the entire surface of one surface of the substrate, or may be formed in a desired shape after patterning. Examples of the desired shape of the electrode include a comb-shaped or zigzag (zigzag) structure. The electrode may be formed on one of a pair of substrates, or may be formed on both substrates. The formation form of the electrode varies depending on the type of the liquid crystal display element, and for example, in the case of an IPS type liquid crystal display element, the electrode is disposed on one of the pair of substrates, and in the case of the other liquid crystal display element, the electrode is disposed on both of the pair of substrates. The liquid crystal alignment film is formed on the substrate or electrode.

The liquid crystal layer may be formed in the following form: the liquid crystal composition is sandwiched between the pair of substrates facing each other on which the liquid crystal alignment film is formed. In the formation of the liquid crystal layer, spacers which are provided between the pair of substrates with a suitable gap therebetween may be used as needed, such as fine particles or resin sheets.

As a method for forming the liquid crystal layer, for example, a vacuum injection method or a liquid crystal dropping Fill (ODF) method can be used. As the sealant used for bonding the substrate, for example, a UV curable sealant or a thermal curable sealant can be used. The sealant may be printed by, for example, screen printing.

The liquid crystal composition is not particularly limited, and various liquid crystal compositions having positive or negative dielectric anisotropy may be used. Preferred liquid crystal compositions having positive dielectric anisotropy include: liquid crystal compositions disclosed in Japanese patent application laid-open No. 3086228, japanese patent application laid-open No. 2635435, japanese patent application laid-open No. 5-501735, japanese patent application laid-open No. 8-157826, japanese patent application laid-open No. 8-231960, japanese patent application laid-open No. 9-241644 (EP 885272A 1), japanese patent application laid-open No. 9-302346 (EP 806466A 1), japanese patent application laid-open No. 8-199168 (EP 722998A 1), japanese patent application laid-open No. 9-235552, japanese patent application laid-open No. 9-255956, japanese patent application laid-open No. 9-241643 (EP 88527IA 1), japanese patent application laid-open No. 10-204016 (EP 844229A 1), japanese patent application laid-open No. 10-204436, japanese patent application laid-open No. 10-231482, japanese patent application laid-open No. 2000-087040, japanese patent application laid-open No. 2001-48822, and the like.

Preferable examples of the liquid crystal composition having negative dielectric anisotropy include: japanese patent application laid-open No. 57-114532, japanese patent application laid-open No. 2-4725, japanese patent application laid-open No. 4-224885, japanese patent application laid-open No. 8-40953, japanese patent application laid-open No. 8-104869, japanese patent application laid-open No. 10-168076, japanese patent application laid-open No. 10-168453, japanese patent application laid-open No. 10-236989, japanese patent application laid-open No. 10-236990, japanese patent application laid-open No. 10-236992, japanese patent application laid-open No. 10-236993, japanese patent application laid-open No. 10-236994, japanese patent application laid-open No. 10-237000, japanese patent application laid-open No. 10-237004, japanese patent application laid-open No. 10-237024, japanese patent application laid-open No. 10-237035, japanese patent application laid-open No. 10-237075, japanese patent application laid-open No. 10-5228 Japanese patent application laid-open No. 10-237076, japanese patent application laid-open No. 10-237448 (EP 967261A 1), japanese patent application laid-open No. 10-287874, japanese patent application laid-open No. 10-287875, japanese patent application laid-open No. 10-291945, japanese patent application laid-open No. 11-029581, japanese patent application laid-open No. 11-080049, japanese patent application laid-open No. 2000-256307, japanese patent application laid-open No. 2001-019965, japanese patent application laid-open No. 2001-626, japanese patent application laid-open No. 2001-192657, japanese patent application laid-open No. 2010-037428, international publication No. 2011/024366, international publication No. 2010/072370, japanese patent application laid-open No. 2010-537, japanese patent application laid-open No. 2012-077201, A liquid crystal composition disclosed in japanese patent laid-open publication No. 2009-084362 and the like. The liquid crystal composition having positive or negative dielectric anisotropy is used by adding one or more optically active compounds thereto.

In addition, for example, the liquid crystal composition used in the liquid crystal display element of the present invention may further contain additives from the viewpoint of improving alignment properties. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, and the like. Preferred examples of the photopolymerizable monomer, the optically active compound, the antioxidant, the ultraviolet absorber, the pigment, the defoamer, the polymerization initiator and the polymerization inhibitor include those disclosed in International publication No. 2015/146330.

In order to be suitable for a liquid crystal display element of a polymer stabilized alignment (polymer sustained alignment, PSA) mode, a polymerizable compound may be mixed into the liquid crystal composition. Preferred examples of the polymerizable compound are compounds having a polymerizable group such as acrylic acid ester, methacrylic acid ester, vinyl compound, vinyloxy compound, propenyl ether, epoxy compound (oxetane ), vinyl ketone and the like. Preferred compounds include those disclosed in International publication No. 2015/146330.

Examples

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods and compounds used in the examples are as follows.

1. Weight average molecular weight (Mw)

The weight average molecular weight of the polyamic acid was determined by measuring the polyamic acid by GPC method using 2695 separation module and 2414 differential refractometer (manufactured by Waters), and converting the polyamic acid into polystyrene. The polyamic acid thus obtained was diluted with a phosphoric acid-DMF mixed solution (phosphoric acid/dmf=0.6/100:weight ratio) in such a manner that the concentration of the polyamic acid was about 2 wt%. The column was manufactured using HSPgel RT MB-M (Waters), and the mixed solution was used as a developing agent and was measured at a column temperature of 50℃and a flow rate of 0.40 mL/min. The standard polystyrene used was TSK standard polystyrene manufactured by Tosoh (Stro).

2. Pretilt angle (Pt angle)

The measurement was performed at room temperature using a liquid crystal evaluation device (OMS-CA 3) manufactured by Central processing Unit (Strand). In order to obtain a wide viewing angle, it is preferably 1.5 ° or less, more preferably 1.2 ° or less.

DC afterimage evaluation

After applying a 30Hz, 3V rectangular wave for 10 minutes, a 0.3V DC voltage was applied for 20 minutes. After the dc voltage was set to 0V, a rectangular wave of 3V was applied again for 20 minutes. The faster the charge absorption at the time of the DC voltage superimposition becomes, the smaller the residual DC at the time of the AC driving which becomes asymmetric becomes, and the more difficult the DC afterimage is generated, so that the case where the flicker removal voltage becomes 0.15V or less after the superimposition of the DC voltage until twenty minutes elapses is defined as "o" and the case where it becomes 0.1V or less is defined as "c". The DC residual image was defined and evaluated as "x" when the flicker eliminating voltage was not 0.15V or less after the DC voltage was superimposed and until twenty minutes elapsed.

4. Voltage holding ratio

The method described in "Water island, etc., draft set p78 (1988)" was used for the 14 th liquid crystal discussion. The measurement was performed by applying a rectangular wave with a frequency of 30Hz and a wave height of + -5V to the cell (cell). The measurement was performed at 60 ℃. The value is a criterion indicating how much the applied voltage is held after the frame period, and if the value is 100%, it indicates that all the charges are held. When the value is 99.5% or more, a liquid crystal display element having good display quality is obtained.

< solvent >

NMP: n-methyl-2-pyrrolidone

BC: butyl cellosolve (ethylene glycol monobutyl ether)

GBL: gamma-butyrolactone.

< additive >

Additive (Ad 1): 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene

Additive (Ad 2): 3-aminopropyl triethoxysilane

Additive (Ad 3): 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane.

Synthesis example 1a Synthesis of Compound (1-4)

The reagents used for synthesis may be used as they are without any purification.

< stage 1 >

To a 1L three-necked flask equipped with a dropping funnel and a thermometer was added 50.0g (236.9 mmol) of octanoyl chloride and 250mL of methylene chloride (dichlormethane). The solution was cooled to 5 ℃ and 75.8g (568.6 mmol,2.4 eq.) of aluminum (III) chloride was added. After the solution was kept at 5℃and stirred for 30 minutes, a solution in which 38.9g (497.5 mmol,2.1 eq.) of benzene was dissolved in 250mL of methylene chloride was added dropwise. After the completion of the dropwise addition, cooling of the solution was stopped, the temperature was raised to room temperature, and the solution was stirred at room temperature for 12 hours. The series of reactions were carried out under nitrogen. The reaction solution was poured into 1500mL of 3NHCl, and the organic layer was recovered and washed 3 times with 500mL of pure water. After washing, the organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain crude crystals. The obtained crude crystals were recrystallized from toluene, and the obtained crystals were dried under vacuum at 80℃for 12 hours to obtain 1, 8-diphenyloctane-1, 8-dione (yield: 61.4g, yield: 88%).

< stage 2 >

50.0g (170.0 mmol) of 1, 8-diphenyloctane-1, 8-dione obtained in stage 1 was charged into a 1L three-necked flask equipped with a dropping funnel and a thermometer, and 500mL of methylene chloride was added. The solution was cooled to 5℃and 70.9g (374.0 mmol,2.2 eq.) of titanium tetrachloride (IV) were added dropwise. After the solution was kept at 5℃and stirred for 1 hour, 59.3g (510.0 mmol,3.0 eq.) of triethylsilane was further added dropwise. The solution was kept at 5 ℃ and stirred for 6 hours. The series of reactions were carried out under nitrogen. The reaction solution was poured into 1L of pure water, and the organic layer was recovered and washed 3 times with 500mL of saturated sodium bicarbonate water, followed by 3 times with 500mL of pure water. After washing, the organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain a bold. The obtained crude product was separated and purified by column chromatography (filler: silica gel, developing solvent: toluene: heptane=2:1) to obtain 1, 8-diphenyloctane (yield: 42.6g, yield: 94%).

< stage 3 >

[ chemical 26]

To a 1L three-necked flask equipped with a dropping funnel and a thermometer was added 50.1g (270.2 mmol,2.4 eq.) of 4-nitrobenzoyl chloride and 250mL of methylene chloride. The solution was cooled to 5 ℃ and 45.0g (337.8 mmol,3.0 eq.) of aluminum (III) chloride was added. After the solution was kept at 5℃and stirred for 30 minutes, a solution obtained by dissolving 30.0g (112.6 mmol) of 1, 8-diphenyloctane obtained in the 2 nd stage in 150mL of methylene chloride was added dropwise. After the completion of the dropwise addition, cooling of the solution was stopped, the temperature was raised to room temperature, and the solution was stirred at room temperature for 12 hours. The series of reactions were carried out under nitrogen. The reaction solution was poured into 1500mL of 3NHCl, and the organic layer was recovered and washed 3 times with 500mL of pure water. After washing, the organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain a bold. The obtained crude body was separated and purified by column chromatography (filler: silica gel, developing solvent: methylene chloride) to obtain compound (1-4) -NK (yield: 52.1g, yield: 82%).

< stage 4 >

[ chemical 27]

To a 1L three-necked flask equipped with a dropping funnel and a thermometer was added 500mL of methylene chloride together with 50.0g (88.6 mmol) of the compound (1-4) -NK50.0g obtained in the 3 rd stage. The solution was cooled to 5℃and 37.0g (194.9 mmol,2.2 eq.) of titanium tetrachloride (IV) was added dropwise thereto. After the solution was kept at 5 ℃ and stirred for 1 hour, 30.9g (265.8 mmol,3.0 eq.) of triethylsilane was added dropwise thereto. The solution was kept at 5 ℃ and stirred for 4 hours. The series of reactions were carried out under nitrogen. The reaction solution was poured into 1L of pure water, and the organic layer was recovered and washed 3 times with 500mL of saturated sodium bicarbonate water, followed by 3 times with 500mL of pure water. After washing, the organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain a bold. The obtained crude body was separated and purified by column chromatography (filler: silica gel, developing solvent: tetrahydrofuran) to obtain compound (1-4) -N (yield: 41.7g, yield: 88%).

< stage 5 >

To a 3L autoclave reactor tube made of SUS316, 40.0g (74.5 mmol) of the compound (1-4) -N obtained in the 4 th stage, 4.0g of 5% Pd/C powder (E type) and 800mL of tetrahydrofuran were added. The solution was stirred under hydrogen atmosphere (hydrogen pressure: 0.6 MPa) at 60℃for 18 hours, cooled by standing, pd/C powder was removed by filtration, and the solvent was distilled off under reduced pressure to give a crude product of the compound (1-4). The obtained crude body was separated and purified by column chromatography (filler: silica gel, developing solvent: tetrahydrofuran), and then recrystallized from a mixed solvent of ethanol: toluene=2:1 (volume ratio), and the obtained crystals were vacuum-dried at 80℃for 12 hours to obtain compound (1-4) (yield: 32.0g, yield: 90%).

The melting point of the obtained compound (1-4) was 113.3℃to 114.7 ℃. Melting points were measured using an automatic melting point measuring system MP-70 manufactured by Mettler Toledo (Inc.).

Synthesis example 1 Synthesis of varnish

To a 100mL three-necked flask equipped with a stirring blade and a nitrogen inlet tube, 4.001g of the compound represented by the formula (1 v 1) was added, and 54.0g of NMP was added. After the solution was ice-cooled to a liquid temperature of 5 ℃, 0.390g of the compound represented by the formula (AN-1), 0.965g of the compound represented by the formula (AN-4), 0.644g of the compound represented by the formula (AN-6), and 20.0g of nmp were added, and stirred at room temperature for 12 hours. To this was added 20.0g of BC, and the solution was heated and stirred at 70℃until the weight average molecular weight of the polymer of the solute became the desired weight average molecular weight, to obtain a varnish 1 having a solid content of 6% by weight. The weight average molecular weight (Mw) of the polymer contained in the varnish 1 was 60,000.

Synthesis examples 2 to 55

In accordance with Synthesis example 1, varnishes 2 to 55 were prepared with a polymer solid content of 6% by weight, except that the tetracarboxylic dianhydride and the diamine were changed. The composition and weight average molecular weight (Mw) of the obtained varnish are shown in tables 1 to 5. Synthesis example 1 is also disclosed again. [] The molar ratio of each of the tetracarboxylic acid compound group and the diamine compound group is shown in the figure.

TABLE 1

TABLE 1

/>

TABLE 2

TABLE 2

TABLE 3

TABLE 3 Table 3

TABLE 4

TABLE 4 Table 4

TABLE 5

TABLE 5

Example 1 preparation of liquid Crystal alignment agent, preparation of liquid Crystal cell for DC residual image and Pre-Tilt measurement, DC residual image measurement, and Pre-Tilt measurement

3.0g of the varnish 1 synthesized in Synthesis example 1 and 7.0g of the varnish 27 synthesized in Synthesis example 27 were weighed into a 50mL eggplant-shaped flask equipped with a stirring blade and a nitrogen inlet tube, 4.0g of NMP, 3.0g of GBL and 3.0g of BC were added thereto, and stirred at room temperature for 1 hour to obtain a liquid crystal aligning agent 1 having a resin component concentration of 3% by weight. The liquid crystal alignment agent 1 was coated on the glass substrate with FFS electrode and the glass substrate with column spacers by a rotator method (2,000 rpm,15 seconds). After the coating, the film was pre-calcined at 80℃for about 3 minutes, and then calcined at 230℃for 30 minutes, to thereby form a liquid crystal alignment film having a film thickness of about 100 nm. The obtained liquid crystal alignment film was subjected to a rubbing treatment under conditions of a rubbing cloth (wool length 2.8mm: cotton) having a wool press-in amount of 0.40mm, a stage moving speed of 20mm/sec, and a roll rotating speed of 1000rpm using a rubbing treatment apparatus manufactured by Dimensions Inc. of Dimensions Meter (iinuma-gauge). The obtained substrate was washed with ultrapure water and dried in an oven at 120℃for 30 minutes. Then, the 2 substrates having the liquid crystal alignment films formed thereon were bonded to each other with the surfaces having the liquid crystal alignment films formed thereon facing each other with a gap for injecting a liquid crystal composition between the facing liquid crystal alignment films. At this time, the rubbing directions of the respective liquid crystal alignment films are parallel. These cells were vacuum-injected with a positive type liquid crystal composition a and the injection port was sealed with a photo-curing agent, thereby producing a liquid crystal cell (liquid crystal display element) having a cell thickness of 4 μm.

< Positive liquid Crystal composition A >

[ chemical 28]

Physical properties: NI100.1 ℃; Δε5.1; Δn0.093; η25.6mPa.s.

The DC residual image of the liquid crystal cell was measured, and the result was ". The pretilt angle was measured and found to be 0.7 °. Further, the voltage holding ratio of the liquid crystal cell was 99.8% at 5V-30 Hz. The units were tested in a lighted backlight tester (Fuji film (stock) manufactured, fuji color LED viewer (FujiCOLOR LED Viewer) Pro HR-2; brightness 2,700 cd/m) ² ) The test piece was placed on the test piece for 500 hours, and a reliability test was performed. The voltage holding ratio of the measurement cell after the reliability test was 99.7%.

Examples 2 to 23 and comparative examples 1 to 3

Except for changing the varnish used, a liquid crystal cell was produced according to example 1, and DC residual image, pretilt angle and voltage holding ratio were measured. The varnish used and the measurement results are shown in table 6 together with example 1. Here, the varnish P is a varnish composition in which the polymer (P) component is dissolved in a solvent. Varnish Q is a varnish composition in which the polymer (Q) component is dissolved in a solvent.

TABLE 6

TABLE 6

In all of examples 1 to 23, the DC afterimages were "Σ" and "verygood". The pretilt angle is 1.2 DEG or less, and the voltage holding ratio is 99.5% or more. In comparative example 1, the DC afterimage was "verygood", but the pretilt angle was as high as 2.3 °. In comparative example 2, the pretilt angle was 1.5 ° or less, but the DC afterimage was "x". In comparative example 3, the DC afterimage was "verygood", but the pretilt angle was as high as 2.2 °.

Example 24

A liquid crystal aligning agent 27 was obtained according to example 1, except that "3.0g of the varnish 1 synthesized in Synthesis example 1 and" 7.0g of the varnish 27 synthesized in Synthesis example 27 "were changed to" 10.0g of the varnish 3 synthesized in Synthesis example 3 ". Using the obtained liquid crystal alignment agent 27, a liquid crystal cell was produced in accordance with the method described in example 1, and DC residual image, pretilt angle, and voltage holding ratio were measured. The DC afterimage of the liquid crystal cell was "Σ", and the pretilt angle was 0.6 °. The initial voltage holding ratio was 99.8%, and the voltage holding ratio of the measurement cell after the reliability test was 99.7%.

Examples 25 to 45, comparative examples 4 to 6, and reference examples 1 to 2

Except for changing the varnish used, a liquid crystal cell was produced according to example 24, and DC residual image, pretilt angle and voltage holding ratio were measured. The varnish used and the measurement results are shown in table 7 together with example 24.

TABLE 7

TABLE 7

In all of examples 24 to 45, the DC afterimage was "Σ" or "verygood". The pretilt angle is 1.5 DEG or less, and the voltage holding ratio is 99.5% or more. In comparative example 4, the pretilt angle was 1.5 ° or less, but the DC afterimage was "x". In comparative example 5, the DC afterimage was "verygood", but the pretilt angle was as high as 2.1 °, and the low pretilt angle could not be exhibited. In comparative example 6, the DC afterimage was "verygood", but the pretilt angle was as high as 2.0 °, and the low pretilt angle could not be exhibited. In reference example 1, DC afterimage was "x", but pretilt angle was 0.3 °, surprisingly low. In reference example 2, the DC afterimage was also "x", but the pretilt angle was 0.2 °, surprisingly low. It is known that in the embodiment in which the liquid crystal aligning agent comprises one polymer, the liquid crystal aligning agent comprising only the diamine of the formula (1-4) in the polymer as a reaction product derived from the raw materials comprising tetracarboxylic dianhydride and diamine exhibits an effect of surprisingly reducing the pretilt angle.

Example 46

According to example 1, except that 6mg of the additive (Ad 1) was further added to "nmp4.0g, gbl3.0g, and bc3.0g" of example 1, a liquid crystal aligning agent 54 having a resin component concentration of 3 wt% and an additive concentration of 1 part by weight per 100 parts by weight of the resin component was obtained. Using the obtained liquid crystal alignment agent 54, a liquid crystal cell was produced in accordance with the method described in example 1, and DC residual image, pretilt angle, and voltage holding ratio were measured. The DC afterimage of the liquid crystal cell was "", and the pretilt angle was 0.9 °. The initial voltage holding ratio was 99.8%, and the voltage holding ratio of the measurement cell after the reliability test was 99.6%.

Examples 47 to 60 and comparative examples 7 to 9

A liquid crystal cell was produced according to example 46, except that the varnish and additives used were changed, and DC residual images, pretilt angles, and voltage holding ratios were measured. The varnish, additives and measurement results used are shown in Table 8 together with example 46.

TABLE 8

TABLE 8

In all of examples 46 to 60, the DC afterimage was "". The pretilt angle is 1.5 DEG or less, and the voltage holding ratio is 99.5% or more. In comparative example 7, the DC afterimage was "verygood", but the pretilt angle was as high as 2.4 °. In comparative example 8, the pretilt angle was 1.5 ° or less, but the DC afterimage was "x". In comparative example 9, the DC afterimage was "verygood", but the pretilt angle was as high as 2.3 °.

Example 61

A liquid crystal aligning agent 72 having a resin component concentration of 3 wt% and an additive concentration of 1 part by weight per 100 parts by weight of the resin component was obtained according to example 1, except that 6mg of the additive (Ad 1) was further added to "nmp4.0g, gbl3.0g and bc3.0g" in example 24. Using the obtained liquid crystal alignment agent 72, a liquid crystal cell was produced in accordance with the method described in example 1, and DC residual image, pretilt angle, and voltage holding ratio were measured. The DC afterimage of the liquid crystal cell was "Σ", and the pretilt angle was 0.8 °. The initial voltage holding ratio was 99.7%, and the voltage holding ratio of the measurement cell after the reliability test was 99.6%.

Examples 62 to 82, comparative examples 10 to 12, and reference examples 3 to 4

A liquid crystal cell was produced according to example 61 except that the varnish and additives used were changed, and DC residual images, pretilt angles, and voltage holding ratios were measured. The varnish, additives and measurement results used are shown in Table 9 together with example 61.

TABLE 9

TABLE 9

In all of examples 61 to 82, the DC afterimage was "Σ" or "verygood". The pretilt angle is 1.5 DEG or less, and the voltage holding ratio is 99.5% or more. In comparative example 10, the pretilt angle was 1.5 ° or less, but the DC afterimage was "x". In comparative example 11, the DC afterimage was "verygood", but the pretilt angle was as high as 2.2 °, and the low pretilt angle could not be exhibited. In comparative example 12, the DC afterimage was "verygood", but the pretilt angle was as high as 2.2 °, and the low pretilt angle could not be exhibited. In reference example 3, DC afterimage was "x", but pretilt angle was 0.4 °, surprisingly low. In reference example 4, the DC afterimage was also "x", but the pretilt angle was 0.3 °, surprisingly low. In the embodiment in which the liquid crystal aligning agent comprises one polymer, it is known that the liquid crystal aligning agent in which the diamine in the polymer comprises only the formula (1-4) as a reaction product derived from the raw materials comprising tetracarboxylic dianhydride and diamine can exert an effect of intentionally reducing the pretilt angle even if an additive is added.

Industrial applicability

When the liquid crystal aligning agent of the present invention is used, a liquid crystal alignment film of a liquid crystal display element can be formed which can suppress the pretilt angle of liquid crystal to a low level, and which has a small accumulation of residual DC and a rapid relaxation of electric charge. The liquid crystal aligning agent of the present invention can be suitably used in a transverse electric field type liquid crystal display element.

Claims (24)

1. A liquid crystal aligning agent comprising at least one polymer which is a reaction product derived from a raw material comprising tetracarboxylic dianhydride and diamine, and

the raw materials used for synthesizing the polymer comprise: at least one selected from the group of compounds represented by the following formulas (1) to (3), at least one selected from the group of compounds represented by the following formulas (A) to (C), and at least one selected from the group of compounds represented by the following formula (D),

wherein the compound represented by the formula (D) comprises a compound represented by the formula (D-2),

here, the polymer is at least one selected from the group consisting of polyamic acid, polyimide, partial polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamideimide;

in the formula (1), m is an integer of 3-8;

in the formula (3), n is an integer of 1 to 3;

In the formulae (1) to (3), a group in which a bonding position is not fixed to any carbon atom constituting a ring means that a bonding position in the ring is arbitrary; and also

In the formula (A), A ¹ Is nitrogen, or a heterocycle containing nitrogen, W ¹ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ¹ Is hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r is an arbitrary integer of 0 or more, and a is independently 0 or 1;

in the formula (B), A ² Independently nitrogen, or a heterocycle containing nitrogen, W ² W and W ³ Independently an alkylene group having 1 to 5 carbon atoms, and optionally-CH ₂ -can be substituted by-CO-, 1, 4-phenylene, or 1, 3-phenylene, Z ² Independently hydrogen, a protecting group substituted with a hydrogen atom by heat, or an alkyl group having 1 to 5 carbon atoms, r independently is an arbitrary integer of 0 or more, and a independently is 0 or 1;

in the formula (C), Z ³ A monovalent organic group containing at least one of a secondary or tertiary amino group;

in the formula (D), T is a divalent unsaturated bond-containing group containing 1 to 2 carbon-carbon double bonds or 1 to 2 carbon-carbon triple bonds;

in the formulae (1) to (3) and (a) to (C), the group whose bonding position is not fixed to any carbon atom constituting the ring represents that the bonding position in the ring is arbitrary, and when m is 8 in the formula (1), the diamine may not include any of the compounds represented by the formulae (a) to (C), and the tetracarboxylic dianhydride may not be the compound represented by the formula (D).

2. The liquid crystal aligning agent according to claim 1, comprising one of the polymers.

3. The liquid crystal aligning agent according to claim 2, wherein the proportion of the compound represented by the formula (1) to the formula (3) is 70 mol% or more relative to the total amount of diamine used, and the proportion of the compound represented by the formula (a) to the formula (C) is 1 mol% to 30 mol% relative to the total amount of diamine used.

4. A liquid crystal aligning agent according to claim 1, comprising at least two of said polymers,

the at least two polymers comprise polymer P and polymer Q;

the raw material for synthesizing the polymer P contains at least one selected from the group of compounds represented by the formulas (1) to (3); and also

The raw material for synthesizing the polymer Q comprises at least one selected from the group of compounds represented by the formulas (A) to (C) and at least one selected from the compounds represented by the formulas (D),

the compound represented by the formula (D) contains a compound represented by the formula (D-2).

5. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the compound represented by the formula (1) to formula (3) is at least one selected from the group of compounds represented by the following formulas (1-1) to (1-4), formula (2-1), formula (2-2), and formulas (3-1) to (3-6);

The compound represented by the formula (A) to the formula (C) is at least one selected from the group of the compounds represented by the following formulas (A-1) to (A-20), the formulas (B-1) to (B-8) and the formulas (C-1) to (C-3);

in the formulae (A-1) to (A-11), a group in which the bonding position is not fixed to any carbon atom constituting the ring means that the bonding position in the ring is arbitrary;

in the formula (B-3), k is an integer of 1 to 5; furthermore, the processing unit is configured to,

in the formula (B-4), n is an integer of 1 to 3.

6. The liquid crystal aligning agent according to claim 5, wherein the compound represented by the formula (1) to formula (3) is at least one selected from the group of the compounds represented by the formula (1-1), the formula (1-4), the formula (2-1), and the formula (3-1);

the compound represented by the formula (A) to the formula (C) is at least one selected from the group of compounds represented by the formula (A-12), the formula (A-14), the formula (A-15), the formula (A-16), the formula (A-17), the formula (A-19), the formula (A-20), the formula (B-3), the formula (B-5), the formula (C-2) and the formula (C-3).

7. The liquid crystal aligning agent according to any one of claims 1 to 3, further comprising at least one selected from compounds represented by the following formula (E) as a raw material for synthesizing the polymer;

H ₂ N-W ⁵ -W ⁴ -W ⁵ -NH ₂ (E)

in the formula (E), W ⁴ Is an alkylene group having 1 to 6 carbon atoms, a 1, 3-phenylene group, or a 1, 4-phenylene group; furthermore, the processing unit is configured to,

W ⁵ independently is a single bond, -NHCO-, or-CONH-.

8. The liquid crystal aligning agent according to claim 4, further comprising at least one selected from the group consisting of compounds represented by the following formula (E) as a raw material for synthesizing the polymer;

H ₂ N-W ⁵ -W ⁴ -W ⁵ -NH ₂ (E)

in the formula (E), W ⁴ Is an alkylene group having 1 to 6 carbon atoms, a 1, 3-phenylene group, or a 1, 4-phenylene group; furthermore, the processing unit is configured to,

W ⁵ independently is a single bond, -NHCO-, or-CONH-.

9. The liquid crystal aligning agent according to claim 5, further comprising at least one selected from the group consisting of compounds represented by the following formula (E) as a raw material for synthesizing the polymer;

H ₂ N-W ⁵ -W ⁴ -W ⁵ -NH ₂ (E)

in the formula (E), W ⁴ Is an alkylene group having 1 to 6 carbon atoms, a 1, 3-phenylene group, or a 1, 4-phenylene group; furthermore, the processing unit is configured to,

W ⁵ independently is a single bond, -NHCO-, or-CONH-.

10. The liquid crystal aligning agent according to claim 7, wherein the compound represented by the formula (E) is at least one compound selected from the group consisting of the compounds represented by the following formulas (E-1) to (E-8);

in the formula (E-5) and the formula (E-8), p is an integer of 1 to 6, respectively.

11. The liquid crystal aligning agent according to claim 8, comprising at least one selected from the compounds represented by the formula (E) as a raw material for synthesizing the polymer Q.

12. The liquid crystal aligning agent according to claim 9, wherein the compound represented by the formula (1) to formula (3) is at least one selected from the group of the compounds represented by the formula (1-1) to formula (1-4), formula (2-1), formula (2-2) and formula (3-1);

the compound represented by the formula (A) to the formula (C) is at least one selected from the group of the compounds represented by the formula (A-12), the formula (A-14), the formula (A-15), the formula (A-16), the formula (A-17), the formula (B-3), the formula (C-2) and the formula (C-3);

the compound represented by the formula (E) is at least one selected from the group of compounds represented by the formulas (E-5) to (E-7),

in the formula (E-5), p is an integer of 1 to 6 independently.

13. The liquid crystal aligning agent according to claim 12, wherein the compound represented by the formula (1) to formula (3) is at least one selected from the group consisting of the formula (1-1) and the formula (1-4);

the compound represented by the formula (A) to the formula (C) is at least one selected from the formula (A-15) and the formula (B-3);

the compound represented by the formula (E) is a compound represented by the formula (E-5).

14. The liquid crystal aligning agent according to claim 4, wherein the proportion of the compound represented by the formula (1) to the formula (3) in the polymer P is 70 mol% or more based on the total amount of diamine used;

In the polymer Q, the proportion of the compound represented by the formula (a) to the formula (C) is 10 mol% to 50 mol% based on the total amount of diamine used.

15. The liquid crystal aligning agent according to claim 4, wherein the proportion of the compound represented by the formula (1) to the formula (3) in the polymer P is 70 mol% or more based on the total amount of diamine used;

in the polymer Q, the proportion of the compound represented by the formula (D) is 20 to 50 mol% relative to the total amount of tetracarboxylic dianhydride used.

16. The liquid crystal aligning agent according to claim 14, wherein the proportion of the compound represented by the formulas (1) to (3) in the polymer P is 90 mol% or more relative to the total amount of diamine used;

in the polymer Q, the proportion of the compound represented by the formula (a) to the formula (C) is 30 mol% to 50 mol% based on the total amount of diamine used.

17. The liquid crystal aligning agent according to claim 15, wherein the proportion of the compound represented by the formula (1) to the formula (3) in the polymer P is 90 mol% or more based on the total amount of diamine used.

18. The liquid crystal aligning agent according to claim 8, wherein the proportion of the compound represented by the formula (E) in the polymer Q is 50 to 70 mol% with respect to the total amount of diamine used.

19. The liquid crystal aligning agent according to any one of claims 1 to 4, further comprising at least one compound selected from the group consisting of an alkenyl-substituted nadic imide compound, a compound having a radical-polymerizable unsaturated double bond, an oxazine compound, an oxazoline compound, and an epoxy compound.

20. The liquid crystal aligning agent according to any one of claims 1 to 4, which is used for manufacturing a transverse electric field type liquid crystal display element.

21. A liquid crystal aligning agent comprising at least one polymer which is a reaction product derived from a raw material comprising tetracarboxylic dianhydride and diamine, and

the diamine contains only a diamine represented by the following formula (1-4),

22. a liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of claims 1 to 21.

23. A liquid crystal display element having the liquid crystal alignment film according to claim 22.

24. A transverse electric field type liquid crystal display element having the liquid crystal alignment film according to claim 22.