JP6102743B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal alignment agent (also referred to as a liquid crystal alignment treatment agent), a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

  The liquid crystal alignment film is a film for controlling the alignment direction of liquid crystal molecules to be constant in a liquid crystal display element, a retardation plate using a polymerizable liquid crystal, or the like. The liquid crystal alignment film is a very important constituent member together with the liquid crystal or the like in a liquid crystal display element or the like.

  2. Description of the Related Art In recent years, in the field of liquid crystal display elements that are becoming more and more advanced, a liquid crystal alignment film is required to have heat resistance, solvent resistance, and the like in addition to the performance of controlling the alignment of liquid crystals (hereinafter also referred to as liquid crystal alignment). Furthermore, various other characteristics are required so that the liquid crystal display element can exhibit high performance.

As one of the characteristics required for the liquid crystal alignment film, there is a characteristic related to improvement in display quality of the liquid crystal display element. For example, a liquid crystal display element is required to improve display defects, and as a countermeasure against display defects, improvement in characteristics of the liquid crystal alignment film is required.
In particular, high display quality is also required for the liquid crystal display elements used in mobile phones and tablet terminals that have recently been rapidly increasing in definition. As a result, the specifications for display defects such as so-called “afterimage phenomenon” or simply “afterimage” are becoming increasingly severe. For example, realization of a liquid crystal alignment film having a characteristic that even if an afterimage occurs is quickly eliminated. In recent liquid crystal display elements, since the usage environment does not stay indoors, high quality performance is required even in places where the temperature is high, such as outdoors or in the car, and a liquid crystal alignment film whose afterimage characteristics do not change at room temperature and high temperature is required. Yes.

  In mobile terminals such as mobile phones, there is a demand for lower power consumption of liquid crystal display elements. Such a portable terminal can be used for a long period of time by charging the battery once due to low power consumption of the liquid crystal display element. In order to reduce the power consumption of the liquid crystal display element, increasing the transmittance of the liquid crystal display element is effective. Therefore, in the liquid crystal display element, in addition to a high aperture ratio of the pixel and the like, an improvement in transmittance is required for constituent members such as a liquid crystal alignment film.

  Further, the liquid crystal alignment film is required to have high resistance to rubbing from the viewpoint of applicability to the manufacturing process of the liquid crystal display element. The rubbing process is known as a method of forming a liquid crystal alignment film in the manufacturing process of a liquid crystal display element, and is still widely used industrially today. In the rubbing process, an alignment process is performed in which a polymer film such as polyimide is formed on a substrate and the surface is rubbed with a cloth.

In the rubbing treatment, there is a problem that dust generated by scraping the liquid crystal alignment film or scratches on the liquid crystal alignment film deteriorates display quality. For this reason, the liquid crystal alignment film is required to have resistance to rubbing treatment (hereinafter also referred to as rubbing resistance).
As a method for forming a liquid crystal alignment film having high rubbing resistance, a method of adding various additives to polyimide constituting the liquid crystal alignment film and a polyimide precursor for forming the polyimide is known ( For example, see Patent Documents 1 and 2.)
In addition, a polyimide structure having good rubbing resistance has been proposed (see, for example, Patent Documents 3 and 4).
By such a method, it is possible to make it difficult to cause the liquid crystal alignment film to be scraped (also referred to as rubbing scraping) or to the liquid crystal alignment film (also referred to as rubbing scratch) during the rubbing treatment.

  However, in recent years, in some applications of liquid crystal display elements, in the rubbing treatment, there is a tendency to perform alignment treatment by rubbing a polymer film such as polyimide more strongly with a cloth. Such a strong rubbing treatment depends on the purpose of making the alignment state of the liquid crystal more uniform and stronger. Therefore, a higher level of rubbing resistance is required for the liquid crystal alignment film.

Japanese Unexamined Patent Publication No. 7-120769 Japanese Unexamined Patent Publication No. 9-146100 Japanese Unexamined Patent Publication No. 2008-90297 Japanese Unexamined Patent Publication No. 9-258229

  An object of the present invention is a liquid crystal alignment that has high liquid crystal alignment and rubbing resistance, is effective in reducing afterimages over a wide temperature range in a liquid crystal display element, and can form a liquid crystal alignment film with high light transmittance. Is to provide an agent.

  Another object of the present invention is to use a liquid crystal aligning agent as described above, which has high liquid crystal alignment and rubbing resistance, is effective in reducing afterimages over a wide temperature range in a liquid crystal display element, and has high light It is to provide a liquid crystal alignment film having transmittance. Furthermore, it is providing the liquid crystal display element which has this liquid crystal aligning film.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the present invention has the following gist.
(1) A liquid crystal aligning agent containing a polyimide precursor obtained by reacting a diamine component with a tetracarboxylic acid derivative,
The diamine component includes a diamine compound represented by the following formula (1) in a total diamine (100 mol%), 20 mol% or more and less than 100 mol% and a diamine compound represented by the following formula (AM1) , and liquid crystal aligning agent wherein the tetracarboxylic acid derivative is characterized the early days containing less 100 mol% to 50 mol% of an aromatic tetracarboxylic acid derivative.

（式（１）中、Ｘは、酸素原子又は硫黄原子であり、Ｙ^１及びＹ^２は、独立して、単結合、−Ｏ−、−Ｓ−、−ＯＣＯ−、又はＣＯＯ−であり、Ｒ^１及びＲ^２は、独立して炭素数１〜３のアルキレン基である。）

（式（ＡＭ１）中、Ｒ ^５ は下記の式（ａ−１）〜式（ａ−２０）からなる群より選ばれる１つの構造を有する２価の有機基を表し、Ｒ ^３ 及びＲ ^４ は、独立して、水素原子又は１価の有機基を表す。）

(In Formula (1), X is an oxygen atom or a sulfur atom, Y < ¹ > and Y < ² > are a single bond, -O-, -S-, -OCO-, or COO- independently, R ¹ and R ² are each independently an alkylene group having 1 to 3 carbon atoms.)

(In formula (AM1), R ⁵ represents a divalent organic group having one structure selected from the group consisting of the following formulas (a-1) to (a-20), and R ³ and R ⁴ are: And independently represents a hydrogen atom or a monovalent organic group.)

( 2 ) In the diamine compound represented by the above formula (AM1), R ⁵ is the above formula (a-1), formula (a-4), formula (a-5), formula (a-6), formula Liquid crystal alignment as described in said ( 1 ) which is a diamine compound which has one structure chosen from the group which consists of (a-10), Formula (a-16), Formula (a-19), and Formula (a-20). Agent.
(3) In the diamine compound represented by the above formula (AM1), R ⁵ is composed of the above formula (a-1), formula (a-4), formula (a-19), and formula (a-20). The liquid crystal aligning agent as described in said (1) which is a diamine compound which has one structure chosen from a group.

(4) the diamine component, the liquid crystal alignment agent according to any one of the above formulas 60 mole% to 30 mole% represented by the diamine compound (1) including (1) to (3).

(5) The tetracarboxylic acid derivative is one or more compounds selected from the group consisting of compounds represented by the following formulas (2-a) to (2-e): (1) to (4) The liquid crystal aligning agent in any one of.

（式（２−ａ）〜式（２−ｅ）中、Ｒ^７はアルキル基を表し、Ｒ^６は下記の式（ｂ−１）〜式（ｂ−８）からなる群より選ばれる１つの構造を有する４価の有機基を表す。）

(In Formula (2-a) to Formula (2-e), R ⁷ represents an alkyl group, and R ⁶ is one selected from the group consisting of Formula (b-1) to Formula (b-8) below. Represents a tetravalent organic group having a structure.)

(6) The liquid crystal aligning agent according to (5), wherein the tetracarboxylic acid derivative is the formula (2-a).

(7) The liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of said (1)-(6).

(8) A liquid crystal display element comprising the liquid crystal alignment film according to (7).

  The present invention provides a liquid crystal aligning agent that has high liquid crystal alignment and rubbing resistance, is effective in reducing afterimages in liquid crystal display elements, and can form a liquid crystal alignment film with high light transmittance. it can.

  The present invention also provides a liquid crystal alignment film having high liquid crystal alignment and rubbing resistance, effective for reducing afterimages in liquid crystal display elements, and having high light transmittance, using the liquid crystal aligning agent. Can do.

  Furthermore, this invention can provide the liquid crystal display element using the liquid crystal aligning film which has the above characteristics.

  The liquid crystal aligning agent of this invention contains the polyimide precursor obtained by making a diamine component and a tetracarboxylic acid derivative react. Examples of the polyimide precursor include polyamic acid and polyamic acid ester.

The polyimide precursor contained in the liquid crystal aligning agent of the present invention is formed using a diamine component having a characteristic structure and a tetracarboxylic acid derivative suitable for realizing desired characteristics by a combination of the diamine component.
Hereinafter, the diamine component and tetracarboxylic acid derivative used for obtaining the polyimide precursor contained in the liquid crystal aligning agent of the present invention will be described in detail.

<Specific diamine compound (1)>
The liquid crystal aligning agent of this invention uses the specific diamine compound of the specific structure represented by following formula (1) as a diamine component for obtaining polyimide precursors, such as a polyamic acid and polyamic acid ester to contain.

In the above formula (1), X is an oxygen atom or a sulfur atom, Y ¹ and Y ² are each independently a single bond, —O—, —S—, —OCO—, or COO—, and R ¹ and R ² are each independently an alkylene group having 1 to 3 carbon atoms.
When X in the formula (1) is an oxygen atom, the specific diamine compound of the formula (1) is a diamine compound having a urea group, and when X is a sulfur atom, a thiourea group (hereinafter referred to as a urea group). And thiourea groups are sometimes collectively referred to as (thio) urea groups).

Preferable examples of the diamine compound represented by the formula (1) include compounds represented by the following formula. Among these, the compounds represented by formula (1-1), formula (1-5) to formula (1-8) are preferable.

  Although the diamine component for obtaining the polyimide precursor contained in the liquid crystal aligning agent of this invention contains the specific diamine compound of the said Formula (1) as an essential component, as content of the specific diamine compound contained, Can be any value.

  In order that the liquid crystal aligning film obtained from the liquid crystal aligning agent of this invention may acquire sufficient rubbing tolerance, the specific diamine compound of the said Formula (1) is 20 mol% or more in all the diamine components (100 mol%). It is preferable that it is preferably 30 mol% or more, and more preferably 50 mol% or more.

In addition, from the viewpoint of optimization of the pretilt angle of the liquid crystal when the polyimide is formed from the polyimide precursor contained in the liquid crystal aligning agent and applied to the liquid crystal display element as the liquid crystal alignment film, or the reduction of the accumulated charge, the above It is preferable that content of the specific diamine compound represented by Formula (1) is less than 100 mol% in all the diamine components, More preferably, it is 30 to 60%.
When the content of the specific diamine compound represented by the above formula (1) is 100 mol% in all diamine components, that is, when all the diamine components are specific diamine compounds represented by the above formula (1), As will be described later, the content of the aromatic tetracarboxylic acid derivative in the tetracarboxylic acid derivative used for forming the polyimide precursor is 50 mol% or more and less than 100 mol% in the total tetracarboxylic acid component. Therefore, in the liquid crystal aligning agent of this invention, all diamine components are the specific diamine compounds of said formula (1), and not all tetracarboxylic acid derivatives are aromatic tetracarboxylic acid derivatives.

<Diamine compound (AM1)>
The polyimide precursor contained in the liquid crystal aligning agent of this invention is obtained by reaction with the diamine component which contains the specific diamine compound represented by the said Formula (1) as an essential component, and a tetracarboxylic acid derivative.
Moreover, the diamine component for obtaining the polyimide precursor of this invention uses the diamine compound represented by a following formula (AM1) together with the specific diamine compound represented by the said Formula (1), and a tetracarboxylic acid derivative and It is preferable to use for this reaction.

In the above formula (AM1), R ⁵ represents a divalent organic group having one structure selected from the group consisting of the following formulas (a-1) to (a-20), and R ³ and R ⁴ are: And independently represents a hydrogen atom or a monovalent organic group.

The diamine compound represented by the above formula (AM1) is formed from a polyimide precursor contained in a liquid crystal aligning agent, and then, from the viewpoint of afterimage reduction when applied to a liquid crystal display element as a liquid crystal alignment film. , R ⁵ is the above formula (a-1), formula (a-4), formula (a-5), formula (a-6), formula (a-10), formula (a-16), formula ( A diamine compound having one structure selected from the group consisting of a-19) and formula (a-20) is preferred. Particularly preferred is a diamine compound having one structure selected from the group consisting of (a-1), (A-4), (A-19) and (a-20).

Moreover, the diamine component for obtaining the polyimide precursor contained in the liquid crystal aligning agent of this invention uses the specific diamine compound of the said Formula (1) as an essential component, The diamine compound represented by the said formula (AM1) is used. Although it is possible to contain, it is also possible to contain diamine compounds other than those.
That is, the diamine component for obtaining the polyimide precursor contained in the liquid crystal aligning agent of this invention is the range which does not impair the effect of this invention, the specific diamine compound of said Formula (1), and the diamine of said Formula (AM1). It is also possible to contain a diamine compound other than the compound.

<Tetracarboxylic acid derivative>
The tetracarboxylic acid derivative that can be used for obtaining the polyimide precursor contained in the liquid crystal aligning agent of the present invention is not particularly limited.
Examples of the tetracarboxylic acid derivative of the present invention include tetracarboxylic dianhydride (represented by the following formula (2-a)), tetracarboxylic acid monoanhydride (represented by the following formula (2-b)), Tetracarboxylic acid (represented by the following formula (2-d)), dicarboxylic acid dialkyl ester (represented by the following formula (2-c)), dicarboxylic acid chloride dialkyl ester (represented by the following formula (2-e)) And the like. The tetracarboxylic acid derivative is not limited to these as long as the reaction with the diamine proceeds.

The tetracarboxylic acid derivative preferably used in the present invention is one or more compounds selected from the group consisting of compounds represented by the following formulas (2-a) to (2-e).
Here, R ⁷ represents an alkyl group.
Specific examples of R ⁶ include the following formulas [A-1] to [A-47].

As the tetracarboxylic acid derivative that can be used for obtaining the polyimide precursor contained in the liquid crystal aligning agent of the present invention, it is particularly preferable to use an aromatic tetracarboxylic acid derivative. All of the tetracarboxylic acid derivatives may be aromatic tetracarboxylic acid derivatives.
In order to obtain the polyimide precursor, two or more tetracarboxylic acid derivatives can be used for the reaction with the diamine component. Even in such a case, it is preferable to use one or more aromatic tetracarboxylic acid derivatives in the tetracarboxylic acid derivative.
Moreover, it is possible to use all of the tetracarboxylic acid derivatives as aromatic tetracarboxylic acid derivatives and to use two or more types of aromatic tetracarboxylic acid derivatives having different structures.

  By including an aromatic tetracarboxylic acid derivative as the tetracarboxylic acid derivative, it is used to form a polyimide precursor, and the liquid crystal alignment property of the obtained liquid crystal alignment film can be improved. At this time, the content of the aromatic tetracarboxylic acid derivative is preferably 50 mol% or more with respect to the total amount of the tetracarboxylic acid derivative used. However, when all the diamine components used for forming the polyimide precursor are diamine compounds represented by the above formula (1), the content of the aromatic tetracarboxylic acid derivative is as described above. It is less than 100 mol% with respect to the total amount of the acid derivative.

As aromatic tetracarboxylic acid derivatives preferably used for obtaining a polyimide precursor contained in the liquid crystal aligning agent of the present invention, compounds represented by the above formulas (2-a) to (2-e) One or more compounds selected from the group consisting of: R ⁷ is an alkyl group, and R ⁶ is one structure selected from the group consisting of the following formulas (b-1) to (b-8): An aromatic tetracarboxylic acid derivative which represents a tetravalent organic group having the same can be given.

The aromatic tetracarboxylic acid derivative having a structure represented by the above formula (2-a) to formula (2-e) and R ⁶ represented by the above formula (b-1) is the specific example of R ⁶ described above. Corresponds to the tetracarboxylic acid derivative represented by the above formula [A-26].
Similarly, in the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-2), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-27]. .
The aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-3) corresponds to a tetracarboxylic acid derivative in which a specific example of R ⁶ is the above formula [A-28].
In the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-4), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-29].
In the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-5), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-31].
In the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-6), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-30].
In the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-7), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-32].
In the aromatic tetracarboxylic acid derivative having a structure in which R ⁶ is represented by the above formula (b-8), a specific example of R ⁶ corresponds to the tetracarboxylic acid derivative represented by the above formula [A-47].

The aromatic tetracarboxylic acid derivatives that are particularly preferably used for obtaining the polyimide precursor contained in the liquid crystal aligning agent of the present invention are represented by the above formulas (2-a) to (2-e). R ⁷ is an alkyl group, R ⁶ is represented by the above formula (b-1), formula (b-2), or formula (b-7). An aromatic tetracarboxylic acid derivative having a structure of

<Polyimide precursor>
As a method for obtaining the polyimide precursor contained in the liquid crystal aligning agent of the present invention, a known method can be used.
A diamine component containing the specific diamine compound of the above formula (1) as an essential component is reacted with a tetracarboxylic acid derivative containing an aromatic tetracarboxylic acid derivative to obtain a polyimide precursor.
The case where tetracarboxylic dianhydride is used as the tetracarboxylic acid derivative will be described below as an example.

  The polymerization reaction method of the diamine component and the tetracarboxylic acid derivative used for the production of the polyimide precursor contained in the liquid crystal aligning agent of the present invention is not particularly limited. By mixing them in an organic solvent, a polymerization reaction can be performed to obtain a polyamic acid that is a polyimide precursor. Moreover, polyamic acid ester can be obtained by esterifying a carboxylic acid group using a known esterifying agent. Polyimide can be obtained by dehydrating and ring-closing the obtained polyamic acid and polyamic acid ester.

As a method of mixing the diamine component and the tetracarboxylic acid derivative in an organic solvent, a solution in which the diamine component is dispersed or dissolved in the organic solvent is stirred, and the tetracarboxylic acid derivative component is added as it is, or tetracarboxylic acid Examples thereof include a method in which the derivative component is added after being dispersed or dissolved in an organic solvent.
Furthermore, a method of adding a diamine component to a solution in which a tetracarboxylic acid derivative is dispersed or dissolved in an organic solvent, a method of alternately adding a tetracarboxylic acid derivative and a diamine, and the like can be mentioned. In addition, when at least one of the tetracarboxylic acid derivative component and the diamine is composed of a plurality of types of compounds, the plurality of types of components may be preliminarily mixed and may be polymerized individually or sequentially. .

  The temperature at which the diamine component and the tetracarboxylic acid derivative are polymerized in an organic solvent is usually 0 to 150 ° C, preferably 5 to 100 ° C, more preferably 10 to 80 ° C. When the temperature is higher, the polymerization reaction is completed earlier, but when it is too high, a high molecular weight polymer may not be obtained. In addition, the polymerization reaction can be carried out at any charge concentration, but if the charge concentration is too low, it will be difficult to obtain a high molecular weight polymer, and if the charge concentration is too high, the reaction solution will become too viscous and uniform. Therefore, the amount is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial stage of the polymerization reaction may be performed at a high concentration, and then an organic solvent may be added. In addition, the above-mentioned preparation density | concentration is a density | concentration of the total mass which match | combined the diamine component and the tetracarboxylic acid derivative.

  The organic solvent used in the above-described polymerization reaction is not particularly limited as long as the generated polyamic acid and polyamic acid ester (hereinafter sometimes referred to as polyamic acid (ester)) are dissolved. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, Examples thereof include γ-butyrolactone. These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyamic acid (ester), it may be used by mixing with the above solvent as long as the produced polyamic acid (ester) does not precipitate.

  Moreover, since water in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyamic acid (ester), it is preferable to use an organic solvent that has been dehydrated and dried as much as possible.

  The ratio of the tetracarboxylic acid derivative and diamine used in the polymerization reaction for obtaining a polyamic acid is preferably 1: 0.8 to 1: 1.2 in terms of molar ratio, and the closer this molar ratio is to 1: 1. The molecular weight of the resulting polyamic acid is increased. If the molecular weight of the polyamic acid (ester) is too small, the strength of the resulting coating film may be insufficient. Conversely, if the molecular weight of the polyamic acid (ester) is too large, the resulting liquid crystal aligning agent has a high viscosity. As a result, the workability at the time of forming the coating film, the uniformity of the coating film, and the like may deteriorate. Therefore, the weight average molecular weight of the polyamic acid (ester) used for the liquid crystal aligning agent of the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000.

The polyamic acid (ester) contained in the liquid crystal aligning agent of the present invention is obtained by a reaction between a diamine component and a tetracarboxylic acid derivative. As the diamine component, the specific diamine compound represented by the above formula (1) is essential. Used as a component of
Moreover, as a diamine component, in addition to the specific diamine compound represented by the said Formula (1), the diamine component containing the diamine compound represented by the said Formula (AM1), and also the diamine component other than those diamine compounds Is used.

  As the tetracarboxylic acid derivative, it is preferable to use a tetracarboxylic acid derivative containing the above-described aromatic tetracarboxylic acid derivative.

The obtained polyamic acid can be represented by a repeating unit of the following formula (3).
Moreover, polyamic acid ester can be represented by following formula (4).

In the above formulas (3) and (4), R ^a , R ^b , and R ^c are each independently a group derived from a diamine compound represented by the above formula (1) or the above formula (AM1).
When the specific diamine compound represented by the above formula (1) is used, R ^a and R ^b are hydrogen atoms, and R ^c is -phenylene-Y ¹ -NH-CX-HN-R ² -Y ² -phenylene- It is. When the diamine compound represented by the above formula (AM1) is used, R ^a is R ³ , R ^b is R ⁴ , and R ^c is R ⁵ .
R ⁶ has the same meaning as R ⁶ in the tetracarboxylic acid derivatives represented by the above formulas (2-a) to (2-e).
R in Formula (4) is a group derived from the esterifying agent used.

  The polyamic acid or polyamic acid ester obtained as described above can be used as it is for the liquid crystal aligning agent of the present invention. Moreover, the liquid crystal aligning agent of this invention can also contain the polyimide which carried out the dehydration ring closure of the polyamic acid or polyamic acid ester obtained by making it above.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention contains the polyimide precursor obtained by making it above, Usually, it can be set as the coating liquid which dissolved these polymers in the organic solvent.
The liquid crystal aligning agent of this invention may contain the polymer obtained from this polyimide precursor other than the above-mentioned polyimide precursor, and the polymer which has another structure.
1-20 mass% is preferable with respect to the whole quantity of a liquid crystal aligning agent, and, as for content of the polyimide precursor in the liquid crystal aligning agent of this invention, 2-20 mass% is more preferable.
The organic solvent contained in the liquid crystal aligning agent of this invention will not be specifically limited if the polymer to contain is dissolved.
80-99 mass% is preferable with respect to the whole quantity of a liquid crystal aligning agent, and, as for the usage-amount of an organic solvent, 80-98 mass% is more preferable.

  Specific examples of the organic solvent used in the liquid crystal aligning agent of the present invention include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, and N-ethyl. Examples include pyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone. You may use these 1 type or in mixture of 2 or more types.

Moreover, even if it is a solvent which does not dissolve polymers, such as a polyimide precursor or a polyimide, if it is a range in which a polymer does not precipitate, it can be mixed with the liquid crystal aligning agent of this invention.
In particular, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy -2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxy Propoxy) propanol, lactic acid methyl ester, lactic acid ethyl ester, lactic acid N-propyl ester, lactic acid N-butyl ester, lactic acid isoamyl ester and other solvents having low surface tension are It is possible to improve the coating uniformity of the substrates of the liquid crystal aligning agent by causing Zaisa. When these solvents are used, one kind or a plurality of kinds may be mixed and used.

  Also in the liquid crystal aligning agent of the present invention, a solvent having a low surface tension is preferably used, but the amount used is more preferably 5 to 80% by mass of the total solvent contained in the liquid crystal aligning agent, and still more preferably. It is 20-60 mass%.

  The liquid crystal aligning agent of the present invention may contain various additives in addition to the above polyimide precursor, a polymer such as polyimide, and an organic solvent as long as the effects of the present invention are not impaired.

  The liquid crystal aligning agent of this invention can contain the additive which improves the film thickness uniformity and surface smoothness of the liquid crystal aligning film formed. Examples of such additives include fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, and the like.

  More specifically, for example, F-top EF301, EF303, EF352 (manufactured by Tochem Products), MegaFuck F171, F173, R-30 (manufactured by Dainippon Ink), Florard FC430, FC431 (manufactured by Sumitomo 3M) ), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.). The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. is there.

  The liquid crystal aligning agent of this invention can contain the additive which improves the adhesiveness of the liquid crystal aligning film formed and a board | substrate. Specific examples of such additives include functional silane-containing compounds and epoxy group-containing compounds.

  For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Propyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N ′,-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N Examples include ', N',-tetraglycidyl-4,4'-diaminodiphenylmethane.

  When adding these compounds, it is preferable that it is 0.1-30 mass parts with respect to 100 mass parts of the polymer component contained in a liquid crystal aligning agent, More preferably, it is 1-20 mass parts. . If the amount is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected. If the amount exceeds 30 parts by mass, the liquid crystal alignment property of the formed liquid crystal alignment film may be lowered.

  In addition to the additives described above, the liquid crystal aligning agent of the present invention has electrical properties such as a polymer component other than the polymer and the dielectric constant and conductivity of the liquid crystal aligning film as long as the effects of the present invention are not impaired. It is possible to add a dielectric material or conductive material to be changed, and a crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film.

  The concentration of the solid content in the liquid crystal alignment agent of the present invention can be appropriately changed depending on the film thickness of the target liquid crystal alignment film. Moreover, it is preferable that the density | concentration of a polymer shall be 1-20 mass% so that a coating film without a defect may be formed and a film thickness suitable as a liquid crystal aligning film can be obtained, More preferably, it is 2 10% by mass.

  Moreover, in the liquid crystal aligning agent of this invention, it is also possible to blend and contain the soluble polyimide, polyamic acid, polyamic acid ester, etc. which consist of a different molecular structure with the polyimide precursor mentioned above. In that case, considering that the obtained polyimide film has desired characteristics, the content of the above-described polyimide precursor of the present invention, other soluble polyimide, polyamic acid, polyamic acid ester, etc. It is preferable to set it as 5-95 mol% with respect to the whole quantity (100 mol%) combined, and 10-90 mol% is more preferable.

The liquid crystal aligning agent of the present invention is applied on a substrate to form a coating film, baked, and then subjected to an alignment treatment by rubbing treatment, light irradiation, etc., and used as a liquid crystal alignment film, or in a vertical alignment application, etc. It can be used as a liquid crystal alignment film without treatment.
The substrate to be used is not particularly limited as long as it is a highly transparent substrate. For example, a plastic substrate such as a glass substrate, an acrylic substrate, or a polycarbonate substrate can be used, and the use of a substrate on which an ITO (Indium Tin Oxide) electrode or the like for driving a liquid crystal is used can simplify the process. To preferred. In the case of configuring a reflective liquid crystal display element, an opaque substance such as a silicon wafer can be used only on one substrate. In this case, a material that reflects light such as aluminum can also be used as the electrode.

  Although the coating method of a liquid crystal aligning agent is not specifically limited, Industrially, coating methods, such as screen printing, offset printing, flexographic printing, and an inkjet, are applicable. As other coating methods, there are coating methods using a dip, a roll coater, a slit coater, a spinner, etc., and these can be used according to the purpose.

Firing of the substrate coated with the liquid crystal aligning agent can be performed at an arbitrary temperature of 100 to 350 ° C, preferably 150 to 300 ° C, more preferably 180 to 250 ° C.
When the liquid crystal aligning agent contains a polyamic acid or a polyamic acid ester, the conversion rate to polyimide varies depending on the baking temperature, but the liquid crystal aligning agent of the present invention does not necessarily need to be imidized 100%.
Furthermore, the baking time of the coating film of a liquid crystal aligning agent can be set to arbitrary time. When the firing time is too short, display failure may occur due to the influence of the residual solvent, and therefore it is preferably 5 to 60 minutes, more preferably 10 to 40 minutes.

If the thickness of the coating film after baking is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, the thickness of the coating film is preferably 5 to 300 nm, more preferably 10 to 100 nm.
When the liquid crystal is aligned horizontally or tilted, it is preferable to perform an alignment treatment on the baked coating film by rubbing or irradiation with polarized ultraviolet rays.

<Liquid crystal display element>
The liquid crystal display element of the present invention uses a substrate with electrodes, etc., and after obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the above-described method, a liquid crystal cell is prepared by a known method, and the liquid crystal display element Can be configured.

About the manufacturing method of a liquid crystal cell, it can carry out as follows, for example.
A pair of substrates on which electrodes and the like for driving the liquid crystal are formed on at least one side is prepared. The liquid crystal alignment film of the present invention is formed on the pair of substrates, and a pair of substrates on which the liquid crystal alignment film is formed is prepared. Next, spacers are dispersed on the liquid crystal alignment film of one substrate, the other substrate is bonded so that the liquid crystal alignment film surface is on the inside, and liquid crystal is injected under reduced pressure to seal. In this way, a liquid crystal display element is produced.
In addition, after preparing a pair of substrates on which the liquid crystal alignment film of the present invention is formed, liquid crystal is dropped on the liquid crystal alignment film surface on which spacers are dispersed, and then the substrates are bonded together for sealing, thereby providing a liquid crystal display element Is made. In these cases, the thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

  As described above, the liquid crystal display element of the present invention produced by using the liquid crystal aligning agent of the present invention is excellent in display quality with reduced afterimage phenomenon, and excellent in reliability and high luminance. Therefore, it can be suitably used for display elements such as large-screen high-definition liquid crystal televisions, smartphones, and tablet devices.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not construed as being limited to these examples.

Abbreviations used in Examples and Comparative Examples are as follows.
DA-1: 1,3-bis (4-aminophenethyl) urea DA-2: paraphenylenediamine DA-3: 1,5-bis (4-aminophenoxy) pentane DA-4: N-methyl 4-aminophenethylamine DA-5: 4,4′-diaminodiphenylmethane DA-6: 4,4′-diaminodiphenylamine DA-7: 1,3-bis (4-aminophenoxy) benzene CA-1: pyromellitic dianhydride CA- 2: 1,2,3,4-cyclobutanetetracarboxylic dianhydride CA-3: 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid Acid anhydride CA-4: 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride CA-5: 2,5-dicarbomethoxy Citeterephthalic acid CA-6: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride

[Example 1]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 8.96 g (30.0 mmol) of DA-1 and 3.24 g (30.0 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 141 g was added and dissolved by stirring while feeding nitrogen. Next, while stirring the diamine solution, 12.82 g (58.7 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. The mixture was stirred at a water temperature for 20 hours to obtain a polyamic acid (P1) solution. It was 297 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P1) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
5.83 g of N-methyl-2-pyrrolidone solution containing 23.37 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 50.30 g of this polyamic acid (P1) solution And 26.49 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P1 concentration of 5.5% by mass.

Table 1 collectively shows the amount (mol) of each tetracarboxylic acid derivative component used in the synthesis of polyamic acid A1 and the amount (mol) of each diamine component.
Similarly, Table 1 shows the amounts (moles) of each tetracarboxylic acid derivative component used in the synthesis of polyamic acids (P2 to P8 and A1 to A6) in Examples 2 to 8 and Comparative Examples 1 to 6 below. ) And the amount (mole) of each diamine component.
Table 2 shows A7 which is a mixed solution of polyamic acid.

(Rubbing resistance evaluation)
The obtained liquid crystal aligning agent is filtered through a 1.0 μm filter, spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 50 ° C. for 5 minutes, and then baked at 230 ° C. for 30 minutes to form a film. A polyimide film having a thickness of 70 nm was obtained. This polyimide film was rubbed with a rayon cloth (roll diameter 120 mm, rotation speed 1000 rpm, moving speed 30 mm / sec, and pushing amount 0.4 mm). The surface of the film was observed using a confocal laser microscope (manufactured by Lasertec Corporation), and the presence and size of scraped residue were observed at a magnification of 10 times. When film abrasion due to rubbing was large, or when film abrasion having a size of 30 μm or more occurred, it was judged as “bad”. When none of such phenomena occurred, the rubbing resistance was judged as “good”. The evaluation results are shown in Table 3.

(Measurement of transmittance (luminous transmittance (Y value (%)))
After the obtained liquid crystal aligning agent is filtered through a 1.0 μm filter, the aligning agent is spin-coated on a quartz substrate, dried on a hot plate at 50 ° C. for 5 minutes, and then baked at 230 ° C. for 30 minutes. A 70 nm thick polyimide film was formed. A double-sided tape was applied only on the two sides facing the coating surface of the substrate, and was bonded to a quartz substrate on which nothing was formed. Liquid paraffin was injected into the obtained simple cell, and transmittance was measured using UV-3100PC manufactured by Shimadzu Corporation. Luminous transmittance was calculated from the obtained data, and a value of 96% or more was defined as “good” and less than 96% was defined as “bad”. The evaluation results are shown in Table 3. The luminous transmittance was calculated using commercially available software (color measurement software manufactured by Shimadzu Corporation: P / N 206-65207).

(Production of liquid crystal cell)
A liquid crystal cell having a configuration of an IPS (In-Plane Switching) mode liquid crystal display element is manufactured.

  First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 50 mm and a thickness of 0.7 mm. On the substrate, an ITO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second SiN film, a comb-like pixel electrode formed by patterning an ITO film as the third layer is arranged to form two pixels, a first pixel and a second pixel. doing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

  The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of dog-shaped electrode elements having a bent central portion. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is configured by arranging a plurality of bent-shaped electrode elements having a bent central portion, the shape of each pixel is not a rectangular shape, and the central portion is similar to the electrode element. It has a shape similar to that of a bold-faced koji that bends at Furthermore, each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

  When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode element of the electrode is formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the direction of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode in the substrate plane is It is comprised so that it may become a mutually reverse direction.

  Next, after filtering the obtained liquid crystal aligning agent with a 1.0 micrometer filter, it spin-coated on each of the prepared board | substrate with an electrode and the glass substrate in which the ITO film | membrane was formed in the back surface. Subsequently, after drying for 5 minutes on a 50 degreeC hotplate, it baked for 30 minutes at 230 degreeC, and obtained the polyimide film on each board | substrate as a 70 nm-thick coating film. This polyimide film is rubbed with a rayon cloth in a predetermined rubbing direction (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm / sec, pushing amount 0.3 mm), and then ultrasonicated in pure water for 1 minute. Irradiated and dried at 80 ° C. for 10 minutes.

  Thereafter, 4 μm bead spacers (manufactured by JGC Catalysts & Chemicals Inc.) were sprayed only on one substrate. Using two types of substrates with a liquid crystal alignment film treated in this way, the rubbing directions are combined so as to be antiparallel, the periphery is sealed leaving a liquid crystal injection port, and the cell gap is 3.6 μm. An empty cell was produced. After liquid crystal (MLC-2041, manufactured by Merck & Co., Inc.) was vacuum-injected into this empty cell at room temperature, the injection port was sealed to obtain an anti-parallel alignment liquid crystal cell. The obtained liquid crystal cell constitutes an IPS mode liquid crystal display element. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

(Afterimage recovery time evaluation (afterimage evaluation))
The afterimage was evaluated using the following optical system and the like.
The prepared liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on with no voltage applied, so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted.
Next, a VT curve (voltage-transmittance curve) was measured while applying an AC voltage with a frequency of 30 Hz to the liquid crystal cell, and an AC voltage with a relative transmittance of 23% was calculated as a drive voltage.

  In the afterimage evaluation, a DC voltage of 2 V was applied at the same time while driving the liquid crystal cell by applying an AC voltage with a relative transmittance of 23% and a frequency of 30 Hz, and was driven for 120 minutes. Thereafter, the applied DC voltage value was set to 0 V, and only the application of the DC voltage was stopped, and the device was further driven for 60 minutes in this state.

The afterimage evaluation was evaluated as “good” when the relative transmittance recovered to 25% or less by 60 minutes after the application of the DC voltage was stopped. When it took 60 minutes or more for the relative transmittance to recover to 25% or less, it was evaluated as “bad”.
The afterimage evaluation according to the above-described method was performed under two types of temperature conditions: a liquid crystal cell temperature of 23 ° C. and a temperature of 60 ° C. The evaluation results are shown in Table 3.

(Long-term drive evaluation (afterimage evaluation))
A liquid crystal cell having the same structure as the liquid crystal cell used for the above-described afterimage evaluation was prepared.
Using this liquid crystal cell, an AC voltage of 8 V _PP was applied for 100 hours at a frequency of 30 Hz in a constant temperature environment of 60 ° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

  After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Furthermore, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as the angle Δ. Similarly, for the second pixel, the second area was compared with the first area, and a similar angle Δ was calculated. Furthermore, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell exceeded 0.2 degrees, it was defined as “defective” and evaluated. When the value of the angle Δ of the liquid crystal cell did not exceed 0.2 degrees, it was evaluated as “good”. The evaluation results are shown in Table 3.

[Example 2]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 7.46 g (25.0 mmol) of DA-1 and 7.15 g (25.0 mmol) of DA-3 were placed, and N-methyl-2-pyrrolidone was added. 143.3 g was added and dissolved while stirring while feeding nitrogen. While stirring this diamine solution, 10.26 g (47.0 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. And stirred for 20 hours to obtain a solution of polyamic acid (P2). It was 305 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P2) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
50.40 g of this polyamic acid (P2) solution is 22.07 g of N-methyl-2-pyrrolidone and 5.74 g of N-methyl-2-pyrrolidone solution containing 1.0% by mass of 3-aminopropyltriethoxysilane. And 26.07 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P2 concentration of 5.5% by mass.

[Example 3]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 4.47 g (15.0 mmol) of DA-1 and 1.62 g (15.0 mmol) of DA-2 were placed, and N-methyl-2- 62.9 g of pyrrolidone was added and dissolved while stirring while feeding nitrogen. While stirring this diamine solution, 1.59 g (6.0 mmol) of CA-3 and 9.0 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 3 hours, 5.04 g (23.1 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at a water temperature in a nitrogen atmosphere for 20 hours. Thus, a solution of polyamic acid (P3) was obtained. It was 280 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P3) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
9.60 g of N-methyl-2-pyrrolidone solution containing 26.92 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 83.48 g of this polyamic acid (P3) solution And 40.0 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P3 concentration of 6.0% by mass.

[Example 4]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 4.83 g (16.2 mmol) of DA-1 and 1.17 g (10.8 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 62.4 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 2.85 g (10.8 mmol) of CA-3 and 8.9 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 3 hours, 3.30 g (15.1 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at a water temperature in a nitrogen atmosphere for 20 hours. Thus, a solution of polyamic acid (P4) was obtained. It was 288 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P4) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
9.60 g of N-methyl-2-pyrrolidone solution containing 27.64 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 82.76 g of this polyamic acid (P4) solution And 40.0 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P4 concentration of 6.0% by mass.

[Example 5]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 1.85 g (6.2 mmol) of DA-1, 1.34 g (12.4 mmol) of DA-2, and 3.55 g of DA-3 ( 12.4 mmol), 64.7 g of N-methyl-2-pyrrolidone was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.43 g (12.4 mmol) of CA-2 and 9.5 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 1 hour, 3.51 g (16.4 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at a water temperature in a nitrogen atmosphere for 20 hours. Thus, a solution of polyamic acid (P5) was obtained. It was 264 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P5) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
9.60 g of N-methyl-2-pyrrolidone solution containing 26.19 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 84.21 g of this polyamic acid (P5) solution And 40.0 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P5 concentration of 6.0% by mass.

[Example 6]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 4.61 g (15.5 mmol) of DA-1 and 1.68 g (15.5 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 62.9 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 1.22 g (6.2 mmol) of CA-2 and 8.7 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 1 hour, 5.04 g (23.1 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at a water temperature in a nitrogen atmosphere for 20 hours. Thus, a solution of polyamic acid (P6) was obtained. It was 262 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P6) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
8.60 g of N-methyl-2-pyrrolidone solution containing 25.44 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 84.96 g of this polyamic acid (P6) solution And 40.0 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P6 concentration of 6.0% by mass.

[Example 7]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 10.39 g (34.8 mmol) of DA-1 and 2.51 g (23.2 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 142.9g was added and it stirred and dissolved, sending nitrogen. While stirring this diamine solution, 3.87 g (19.7 mmol) of CA-2 and 35.0 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 2 hours, 7.82 g (35.9 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred at a water temperature in a nitrogen atmosphere for 20 hours. Thus, a solution of polyamic acid (P7) was obtained. It was 328 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P7) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
12.0 g of N-methyl-2-pyrrolidone solution containing 42.93 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 105.08 g of this polyamic acid (P7) solution And 40.0 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P7 concentration of 6.0% by mass.

[Example 8]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 4.18 g (14.0 mmol) of DA-1 and 2.10 g (14.0 mmol) of DA-4 were placed, and N-methyl-2-pyrrolidone was added. 70.5 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 5.86 g (26.9 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. The solution was stirred for a time to obtain a polyamic acid (P8) solution. It was 311 mPa * s when the viscosity at 25 degrees C of this polyamic acid (P8) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
55.74 g of this polyamic acid (P8) solution is 15.61 g of N-methyl-2-pyrrolidone and 6.2 g of N-methyl-2-pyrrolidone solution containing 1.0% by mass of 3-aminopropyltriethoxysilane. And 25.85 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P8 concentration of 6.0% by mass.

[Example 9]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.94 g (28.1 mmol) of CA-5 and 136.5 g of N-methyl-2-pyrrolidone were added and completely dissolved. Next, 6.16 g of triethylamine was added, 4.33 g (14.5 mmol) of DA-1 and 2.18 g (14.5 mmol) of DA-4 were added and completely dissolved. Thereafter, the reaction solution was cooled with water, and while stirring with a magnetic stirrer, 23.35 g (60.9 mmol) of diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate was added, and 18.75 g of N-methyl-2-pyrrolidone was added and stirring was continued for 5 hours. Thereafter, the reaction solution was poured little by little while stirring isopropyl alcohol having a mass six times that of the reaction solution, and stirring was continued for 1 hour. Thereafter, the precipitate obtained by filtration was stirred with double mass of isopropyl alcohol for 1 hour, and then filtered again to collect the precipitate. Thereafter, this operation was repeated twice, and the resulting precipitate was dried at 100 ° C. under reduced pressure for 24 hours to obtain 10.54 g of a polyamic acid ester (P9). 5.14 g of the obtained solid was completely dissolved with 37.69 g of N-methyl-2-pyrrolidone. Next, 38.55 g of N-methyl-2-pyrrolidone and 20.10 g of butyl cellosolve were added to the solution to obtain a liquid crystal aligning agent having a P9 concentration of 4.5 mass%.

[Example 10]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 1.50 g (5.03 mmol) of DA-1 and 5.85 g (20.0 mmol) of DA-7 were placed, and N-methyl-2-pyrrolidone was added. 73 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 5.21 g (24.0 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. And stirred for 20 hours to obtain a solution of polyamic acid (P10). It was 327 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
15.35 g of N-methyl-2-pyrrolidone and 16.86 g of butyl cellosolve were added to 35.10 g of this polyamic acid solution to obtain a liquid crystal aligning agent having a P10 concentration of 6.0% by mass.

[Example 11]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 3.71 g (12.5 mmol) of DA-1 and 3.65 g (12.5 mmol) of DA-7 were placed, and N-methyl-2-pyrrolidone was added. 73 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution, 5.18 g (23.8 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. And stirred for 20 hours to obtain a solution of polyamic acid (P11). It was 289 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).
To 11.92 g of this polyamic acid solution, 10.74 g of N-methyl-2-pyrrolidone and 8.00 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a P11 concentration of 4.5 mass%.

[Example 12]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 2.21 g (7.41 mmol) of DA-1 and 5.01 g (17.1 mmol) of DA-7 were placed, and N-methyl-2-pyrrolidone was added. 73 g was added and dissolved by stirring while feeding nitrogen. While stirring the diamine solution, 5.07 g (23.2 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. And stirred for 20 hours to obtain a solution of polyamic acid (P12). It was 267 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by the Toki Sangyo company).
20.49 g of N-methyl-2-pyrrolidone and 23.49 g of butyl cellosolve were added to 49.84 g of this polyamic acid solution to obtain a liquid crystal aligning agent having a P12 concentration of 6.0% by mass.

[Example 13]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introducing tube, 1.41 g (4.80 mmol) of DA-1 and 5.61 g (19.2 mmol) of DA-7 were placed, and N-methyl-2- Pyrrolidone 79 g was added and dissolved by stirring while feeding nitrogen. While stirring the diamine solution, 6.77 g (23.0 mmol) of CA-6 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. The mixture was stirred at a water temperature for 20 hours to obtain a polyamic acid (P13) solution. It was 240 mPa * s when the viscosity at 25 degrees C of this polyamic acid solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
7.22 g of N-methyl-2-pyrrolidone and 7.32 g of butyl cellosolve were added to 14.76 g of this polyamic acid solution to obtain a liquid crystal aligning agent having a P13 concentration of 6.0% by mass.

[Comparative Example 1]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 17.75 g (62.0 mmol) of DA-3 was added, 139.1 g of N-methyl-2-pyrrolidone was added, and the mixture was stirred and dissolved while feeding nitrogen. It was. While stirring this diamine solution under water cooling, 12.91 g (59.2 mmol) of CA-1 was added, and N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass. The mixture was stirred for 20 hours while heating at 50 degrees to obtain a solution of polyamic acid (A1). It was 530 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A1) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
5.6 g of an N-methyl-2-pyrrolidone solution containing 43.95 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 50.00 g of this polyamic acid (A1) solution. And 24.89 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having an A1 concentration of 4.5 mass%.

[Comparative Example 2]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 3.25 g (30.0 mmol) of DA-2 and 8.60 g (30.0 mmol) of DA-3 were placed, and N-methyl-2-pyrrolidone was added. 138.1 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 12.59 g (57.7 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and under a nitrogen atmosphere, The solution was stirred for 20 hours to obtain a polyamic acid (A2) solution. It was 310 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A2) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
52.34 g of this polyamic acid (A2) solution is 23.18 g of N-methyl-2-pyrrolidone and 5.98 g of N-methyl-2-pyrrolidone solution containing 1.0% by mass of 3-aminopropyltriethoxysilane. And 27.17 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a concentration of A2 of 5.5% by mass.

[Comparative Example 3]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 7.64 g (25.6 mmol) of DA-1 and 4.15 g (38.4 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 141.6 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 6.81 g (34.7 mmol) of CA-2 and 35.4 g of N-methyl-2-pyrrolidone were added and stirred while feeding nitrogen. After stirring for 2 hours, 5.58 g (25.6 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred for 20 hours in a nitrogen atmosphere. A solution of polyamic acid (A3) was obtained. It was 276 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A3) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
53.33 g of this polyamic acid (A3) solution was 22.12 g of N-methyl-2-pyrrolidone and 6.12 g of N-methyl-2-pyrrolidone solution containing 1.0% by mass of 3-aminopropyltriethoxysilane. And 20.35 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having a concentration of A3 of 6.0% by mass.

[Comparative Example 4]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 3.14 g (10.5 mmol) of DA-1 and 2.64 g (24.4 mmol) of DA-2 were placed, and N-methyl-2-pyrrolidone was added. 71.6 g was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 6.55 g (33.4 mmol) of CA-2 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and a nitrogen atmosphere was added. Under stirring for 20 hours, a solution of polyamic acid (A4) was obtained. It was 274 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A4) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
The N-methyl-2-pyrrolidone solution containing 8.64 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane was added to 20.09 g of this polyamic acid (A4) solution. And 7.76 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having an A4 concentration of 6.0% by mass.

[Comparative Example 5]
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 0.81 g (2.8 mmol) of DA-1, 1.21 g (11.2 mmol) of DA-2, 4.01 g of DA-3 ( 14.0 mmol), 72.6 g of N-methyl-2-pyrrolidone was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 2.67 g (10.1 mmol) of CA-3 was added. After stirring for 2 hours, 3.66 g (16.8 mmol) of CA-1 was added, N-methyl-2-pyrrolidone was further added so that the solid content concentration was 12% by mass, and the mixture was stirred for 20 hours in a nitrogen atmosphere. A solution of polyamic acid (A5) was obtained. It was 358 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A5) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
5.66 g of N-methyl-2-pyrrolidone solution containing 14.51 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 50.59 g of this polyamic acid (A5) solution. And 23.59 g of butyl cellosolve were added to obtain a liquid crystal aligning agent having an A5 concentration of 6.0% by mass.

[Comparative Example 6]
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 7.97 g (40.0 mmol) of DA-6 was added, 98.6 g of N-methyl-2-pyrrolidone was added, and the mixture was stirred and dissolved while feeding nitrogen. It was. While stirring this diamine solution under water cooling, 6.96 g (35.5 mmol) of CA-2 and 35.9 g of N-methyl-2-pyrrolidone were added, and the mixture was stirred under water cooling for 3 hours under a nitrogen atmosphere. Thereafter, 1.98 g (10.0 mmol) of DA-5 and 17.9 g of N-methyl-2-pyrrolidone were added and dissolved by stirring. After DA-5 is dissolved, 3.00 g (10.0 mmol) of CA-4 and 26.9 g of N-methyl-2-pyrrolidone are added, and the mixture is again stirred under a nitrogen atmosphere for 3 hours under water cooling to polyamic acid. A solution of (A6) was obtained. It was 165 mPa * s when the viscosity at 25 degrees C of this polyamic acid (A6) solution was confirmed with the E-type viscosity meter (made by Toki Sangyo Co., Ltd.).
4.9 g of an N-methyl-2-pyrrolidone solution containing 10.55 g of N-methyl-2-pyrrolidone and 1.0% by mass of 3-aminopropyltriethoxysilane in 50.00 g of this polyamic acid (A6) solution. And 16.37 g of butyl cellosolve were added to obtain a solution having a concentration of A6 of 6.0% by mass.

  Further, 24.67 g of N-methyl-2-pyrrolidone and 18.66 g of butyl cellosolve were added to 50.00 g of the polyamic acid solution of A1, and a liquid crystal aligning agent having an A1 concentration of 6.0% by mass was also obtained. These two 6.0% by mass solutions were mixed in an amount such that A1: A6 was 2: 8 to obtain a polyamic acid solution A7.

  Using the liquid crystal aligning agents obtained in Examples 2 to 13 and Comparative Examples 1 to 6, evaluation samples such as films and liquid crystal cells were prepared in the same manner as in Example 1, and rubbing resistance and luminous transmittance were obtained. Evaluation, afterimage evaluation, and afterimage evaluation by long-term driving were performed. The results obtained are shown in Table 3.

  In the film | membrane formed using the liquid crystal aligning agent of Examples 1-13, the rubbing tolerance was favorable and the transmittance | permeability was also favorable. Further, when applied as a liquid crystal alignment film in the evaluation of a liquid crystal cell, there was no temperature dependency of the afterimage evaluation, and the result of the afterimage evaluation by long-term driving was also good.

On the other hand, in the liquid crystal alignment film formed using the liquid crystal aligning agent of Comparative Examples 1-6, it is difficult to combine afterimage characteristics, high transmittance, and rubbing resistance, and all these items cannot be improved. I understood that. In Comparative Example 1 and Comparative Example 2 in which DA-1 was not used as the diamine component, and in Comparative Example 5 in which the amount of DA-1 used as the diamine component was small, it was found that the rubbing resistance was poor.
In Comparative Example 4 in which CA-1 is not used for the tetracarboxylic acid derivative component and in Comparative Example 3 in which the introduction amount is small, afterimage recovery at 23 ° C. is poor. It turned out to be bad.
Moreover, it turned out that the high luminous transmittance cannot be obtained in the comparative example 6 which does not use DA-1.

By using the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having high transmittance, excellent rubbing resistance, and improved display defects such as afterimages in a wide temperature range can be obtained. The liquid crystal alignment film can be used in large-sized liquid crystal televisions, which have conventionally been required to have high display quality, and in liquid crystal display elements for mobile phones and tablet devices that have recently been required to rapidly improve display quality. It is.
The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2011-235976 filed on October 27, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (8)

A liquid crystal aligning agent containing a polyimide precursor obtained by reacting a diamine component and a tetracarboxylic acid derivative,
The diamine component includes a diamine compound represented by the following formula (1) in a total diamine (100 mol%), 20 mol% or more and less than 100 mol% and a diamine compound represented by the following formula (AM1) , and liquid crystal aligning agent wherein the tetracarboxylic acid derivative is characterized the early days containing less 100 mol% to 50 mol% of an aromatic tetracarboxylic acid derivative.

(In Formula (1), X is an oxygen atom or a sulfur atom, Y < ¹ > and Y < ² > are a single bond, -O-, -S-, -OCO-, or COO- independently, R ¹ and R ² are each independently an alkylene group having 1 to 3 carbon atoms.)

(In formula (AM1), R ⁵ represents a divalent organic group having one structure selected from the group consisting of the following formulas (a-1) to (a-20), and R ³ and R ⁴ are: And independently represents a hydrogen atom or a monovalent organic group.)

In the diamine compound represented by the above formula (AM1), R ⁵ has the above formula (a-1), formula (a-4), formula (a-5), formula (a-6), formula (a- 10), the liquid crystal aligning agent of claim 1 wherein the diamine compound having the formula (a-16), 1 single structure selected from the group consisting of formulas (a-19) and formula (a-20). The diamine compound represented by the above formula (AM1) is R ⁵ The diamine compound having one structure selected from the group consisting of the formula (a-1), the formula (a-4), the formula (a-19) and the formula (a-20). Liquid crystal aligning agent. The diamine component, the liquid crystal alignment agent according to any one of diamine compounds 30 mol% to 60 mol% including claims 1-3 represented by the above formula (1). 5. The compound according to claim 1, wherein the tetracarboxylic acid derivative is one or more compounds selected from the group consisting of compounds represented by the following formulas (2-a) to (2-e). The liquid crystal aligning agent of description.

(In Formula (2-a) to Formula (2-e), R ⁷ represents an alkyl group, and R ⁶ is one selected from the group consisting of Formula (b-1) to Formula (b-8) below. Represents a tetravalent organic group having a structure.)

  The liquid crystal aligning agent according to claim 5, wherein the tetracarboxylic acid derivative is a compound represented by the formula (2-a).   It obtains from the liquid crystal aligning agent of any one of Claims 1-6, The liquid crystal aligning film characterized by the above-mentioned.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 7.