TW201920630A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

The present invention provides a substrate having a liquid crystal alignment film that is for an in-plane drive type liquid crystal display element, that is given the capability to control alignment with high efficiency, and that has excellent properties against burning caused by misalignment of liquid crystal or residual DC, and an in-plane drive type liquid crystal display element having the substrate. The present invention provides a liquid crystal alignment agent containing: (A-a) at least one polymer selected from polyamic acids obtained by using a diamine component and a tetracarboxylic acid dianhydride component including a tetracarboxylic acid dianhydride represented by formula (1) (in formula (1), i represents 0 or 1, and X represents a single bond, an ether bond, or the like), and imidized polymers of the polyamic acids; (A-b) at least one polymer selected from polyamic acids obtained by using a tetracarboxylic acid dianhydride component including an aliphatic tetracarboxylic acid dianhydride and a diamine component including a diamine represented by formula (2), and imidized polymers of the polyamic acids; and an organic solvent, wherein the weight ratio of (A-a) and (A-b) is represented as (A-a):(A-b) = 55:45 to 90:10.

Description

Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element for manufacturing a liquid crystal display element having excellent afterimage characteristics.

Liquid crystal display elements are known as light-weight, thin, and low-power display devices. In recent years, they have been used for large-scale television applications and have achieved rapid development. The liquid crystal display element is configured, for example, by sandwiching a liquid crystal layer between a substrate and a transparent one having electrodes. In addition, in a liquid crystal display element, a liquid crystal is brought into a desired alignment state between substrates, and an organic film made of an organic material is used as a liquid crystal alignment film.

That is, the liquid crystal alignment film is a constituent member of a liquid crystal display element, and is formed on a surface of a substrate that holds the liquid crystal in contact with the liquid crystal, and functions to orient the liquid crystal in a specific direction between the substrates. In addition, for the liquid crystal alignment film, in addition to the function of aligning the liquid crystal in a specific direction such as a direction parallel to the substrate, the function of controlling the pretilt angle of the liquid crystal is sometimes required. The ability to control liquid crystal alignment in the liquid crystal alignment film (hereinafter referred to as alignment control ability) can be imparted by performing an alignment treatment on an organic film constituting the liquid crystal alignment film.

A rubbing method has been conventionally known as an alignment treatment method for a liquid crystal alignment film for imparting alignment control ability.
However, the rubbing method of rubbing the surface of a liquid crystal alignment film made of polyimide or the like has problems of raising dust or generating static electricity. In addition, in recent years, high-definition liquid crystal display elements or unevenness caused by electrodes on corresponding substrates or active switching elements for liquid crystal driving have made it impossible to uniformly rub the surface of the liquid crystal alignment film with a cloth. , And cannot achieve uniform liquid crystal alignment.

Therefore, the photo-alignment method is being actively reviewed as another alignment processing method of the liquid crystal alignment film without rubbing. There are various methods of photo-alignment. Anisotropy is formed in an organic film constituting a liquid crystal alignment film by linearly polarized light or parallel light, and the liquid crystal is aligned according to the anisotropy.

The main photo-alignment methods, such as decomposition-type photo-alignment methods, are known. For example, the polyimide film is irradiated with polarized ultraviolet light, and the polarization direction dependence of ultraviolet absorption of molecular structure is used to cause anisotropic decomposition. In addition, the liquid crystal is aligned with polyfluorene imide remaining without being decomposed (for example, refer to Patent Document 1).

A photo-alignment method of a photo-crosslinking type or a photo-isomerization type is also known. For example, using polyvinyl cinnamate and irradiating polarized ultraviolet light, a dimerization reaction (crosslinking reaction) occurs at the double bond portion of the two side chains parallel to the polarized light. In addition, the liquid crystal is aligned in a direction orthogonal to the polarization direction (for example, refer to Non-Patent Document 1). In the case of using a side chain polymer having azobenzene in the side chain, the polarized ultraviolet light is irradiated to cause an isomerization reaction in the azobenzene portion of the side chain parallel to the polarized light, so that the liquid crystal is aligned orthogonal to the direction of the polarization (For example, refer to Non-Patent Document 2).

In addition, a photo-alignment film for improving afterimage characteristics by AC driving is known, for example, a method using a polyamino acid produced by using a diamine containing a cyclobutane ring and a diimino group (see, for example, Patent Documents 2 and 3). And 4).

As in the above example, the alignment processing method of the liquid crystal alignment film by the photo-alignment method does not require friction, and there is no concern about dust or static electricity. In addition, even a substrate of a liquid crystal display element having an unevenness on its surface can be subjected to an alignment treatment, thereby becoming an alignment treatment method for a liquid crystal alignment film suitable for an industrial production process.

In addition, the liquid crystal cell of the transverse electric field method has excellent viewing angle characteristics, but there are fewer electrode portions formed in the substrate, so the voltage retention of the liquid crystal alignment film is weak and a sufficient voltage is not applied to the liquid crystal, and the display contrast is reduced. In addition, static electricity is easily accumulated in the liquid crystal cell. Even if an asymmetric voltage generated by driving is applied, charges will still be accumulated in the liquid crystal cell. These accumulated charges (residual DC) will cause the alignment of the liquid crystal to be disordered, or residual images Or the residual image affects the display, which significantly reduces the display quality of the liquid crystal element. When power is applied again in this state, liquid crystal molecules are not well controlled in the initial stage, and flickers and the like are generated. Especially in the horizontal electric field method, compared with the vertical electric field method, the distance between the pixel electrode and the common electrode is relatively close, so there is a strong electric field effect caused by the alignment film or the liquid crystal layer. This undesired phenomenon easily becomes obvious.
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent No. 3893659
[Patent Document 2] Korean Patent Publication No. 10-2016-0042614
[Patent Document 3] Korean Patent Publication No. 10-2017-0127966
[Patent Document 4] Korean Patent Publication No. 10-2018-0020722
[Non-patent literature]

[Non-Patent Document 1] M. Shadt et al., Jpn. J. Appl. Phys. 31, 2155 (1992).
[Non-Patent Document 2] K. Ichimura et al., Chem. Rev. 100, 1847 (2000).

[Problems to be Solved by the Invention]

As described above, the photo-alignment method does not require a rubbing step as compared to the rubbing method used as an alignment processing method for liquid crystal display elements in the past, and therefore has a great advantage. In addition, compared with the friction method which makes the alignment control ability almost constant by friction, the light alignment method can change the irradiation amount of polarized light to control the alignment control ability. However, when the photo-alignment method intends to achieve the same degree of alignment control capability as in the case of the rubbing method, sometimes a large amount of polarized light irradiation is required or a stable liquid crystal alignment cannot be achieved.

For example, the decomposition-type photo-alignment method described in the aforementioned Patent Document 1 requires that the polyimide film be irradiated with ultraviolet light from a high-pressure mercury lamp with an output of 500 W for 60 minutes, etc., and requires a large amount of ultraviolet radiation for a long time. In addition, in a dimerization-type or photo-isomerization-type photo-alignment method, there may be a case where a large amount of ultraviolet rays ranging from several J (Joules) to several tens J are required. In addition, in the case of the photo-alignment method of the photo-crosslinking type or the photo-isomerization type, the thermal stability or the light stability of the liquid crystal alignment is poor. Therefore, when used as a liquid crystal display element, there are problems such as poor alignment or displaying residual images. In particular, the liquid crystal display element of the transverse electric field driving type switches liquid crystal molecules in the plane, so the alignment deviation of the liquid crystal after the liquid crystal driving is easy to occur, and the problem of displaying residual images is caused by the liquid crystal alignment deviation.

Therefore, the photo-alignment method requires high-efficiency alignment or stable liquid crystal alignment, and a liquid crystal alignment film or liquid crystal alignment agent that can efficiently provide a high alignment control ability to the liquid crystal alignment film.

For countermeasures to display residual images due to residual DC, for example, when using as a liquid crystal alignment film, components different from polyamic acid or polyimide which are provided with the alignment control ability of the liquid crystal by irradiation with polarized ultraviolet light are used. That is, a method in which polyamic acid having a low volume resistivity is added to an alignment agent. However, a liquid crystal alignment agent in which two types of polyamic acid or polyimide are mixed is stored at 23 ° C., and the liquid crystal alignment stability may decrease with the storage time. Therefore, there is a need for a liquid crystal alignment film or a liquid crystal alignment agent that eliminates residual image display caused by residual DC and does not reduce liquid crystal alignment stability.

An object of the present invention is to provide a substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element and a substrate having the liquid crystal alignment film for a transverse electric field driving type, which are efficiently provided with an alignment control capability and have excellent residual image characteristics due to liquid crystal alignment deviation or residual DC. Horizontal electric field drive type liquid crystal display element.

[Means to solve the problem]

The present inventors have carefully reviewed the results in order to solve the above-mentioned problems, and have found that by using a polyamic acid or a polyimide polymer obtained from a specific aromatic tetracarboxylic dianhydride and a diamine, and Polyamidic acid or polyimide polyimide polymer obtained from an aliphatic tetracarboxylic dianhydride and a diamine having a specific structure can obtain an alignment control ability efficiently. The liquid crystal alignment film with excellent residual image characteristics caused by residual DC completes the present invention.

As described above, the present invention has the following technical features based on the above-mentioned findings.
A liquid crystal alignment agent comprising (Aa) selected from a polyamino acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing a tetracarboxylic dianhydride represented by the following formula (1) ( Polymers of at least one kind of polyimide-imidized polymer,
(Ab) It is selected from the group consisting of a polyamic acid obtained by using a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the following formula (2) and a polyamine至少 at least one kind of polymer of imidized polymer and organic solvent,
The weight ratio of (Aa) and (Ab) is (Aa) :( Ab) = 55: 45 ~ 90: 10, preferably 60: 40 ~ 90: 10, and more preferably 60: 40 ~ 85: 15.

In formula (1), i is 0 or 1, and X is a single bond, an ether bond, a carbonyl group, an ester bond, a phenylene group, a linear alkylene group having 1 to 20 carbon atoms, and a branch having 2 to 20 carbon atoms. Chain alkylene, cyclic alkylene having 3 to 12 carbon atoms, sulfofluorenyl group, amido bond, or a combination thereof, here, alkylene having 1 to 20 carbon atoms may be Interrupted by a bond selected from an ester bond and an ether bond, the carbon atoms of phenylene and alkylene may be selected from halogen atoms, cyano, alkyl, haloalkyl, alkoxy and haloalkoxy 1 or more of the same or different substituents.

2. The liquid crystal alignment agent according to 1, wherein 10 to 100 mole% of the tetracarboxylic dianhydride component of the aforementioned (Aa) is a tetracarboxylic dianhydride represented by the aforementioned formula (1).
3. The liquid crystal alignment agent according to 1 or 2, wherein 10 to 100 mole% of the tetracarboxylic dianhydride component of the aforementioned (Ab) is an aliphatic tetracarboxylic dianhydride.
4. The liquid crystal alignment agent according to any one of 1 to 3, wherein 10 to 100 mole% of the diamine component of the aforementioned (Ab) is a diamine of the formula (2).

5. The liquid crystal alignment agent according to any one of 1 to 4, wherein the tetracarboxylic dianhydride represented by the aforementioned formula (1) is selected from pyromellitic dianhydride and 3,3 ', 4,4'-biphenyl At least one type of tetracarboxylic dianhydride.
6. The liquid crystal alignment agent according to any one of 1 to 5, wherein the aliphatic tetracarboxylic dianhydride is cyclobutane tetracarboxylic dianhydride or 1,3-dimethylcyclobutane tetracarboxylic dianhydride.

7. A method for manufacturing a substrate having a liquid crystal alignment film, which comprises the following steps [I] to [III] to obtain a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element to which alignment control ability is provided,
[I] a step of coating the composition of any one of the above 1 to 6 on a substrate having a conductive film for driving a transverse electric field to form a coating film;
[II] a step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and
[III] A step of heating the coating film obtained in [II].
8. A substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element, which is manufactured by the method of 7 above.
9. A transverse electric field-driven liquid crystal display device comprising the substrate according to 8 above.

10. A method for manufacturing a liquid crystal display device, which comprises the following steps to obtain a liquid crystal display device driven by a transverse electric field,
Steps for preparing the substrate (first substrate) as described in 8 above;
By having: [I '] a step of forming a coating film by coating the composition according to any one of the above 1 to 6 on the second substrate;
[II '] a step of irradiating the coating film obtained in [I'] with polarized ultraviolet rays; and
[III '] a step of heating the coating film obtained in [II'];
A step of obtaining a liquid crystal alignment film having an alignment control capability, and a step of obtaining a second substrate having the liquid crystal alignment film; and
[IV] A step of obtaining the liquid crystal display element by facing the liquid crystal alignment films of the first and second substrates through liquid crystal, and arranging the first and second substrates in an opposite direction.
11. A transverse electric field-driven liquid crystal display device manufactured by the method according to the above-mentioned 10.

[Inventive effect]

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can align the liquid crystal with a small amount of polarized ultraviolet radiation. Even if the liquid crystal alignment agent is stored at 23 ° C, the liquid crystal alignment stability of the liquid crystal alignment film will not be deteriorated. Quickly alleviate residual DC accumulated by DC voltage.

[Form of Implementing Invention]

The liquid crystal alignment agent of the present invention contains (Aa) a polyamic acid selected from the group consisting of a polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing a tetracarboxylic dianhydride represented by the following formula (1), and the polymer (Ab) A polymer of at least one kind of amidinated imidized polymer selected from the group consisting of the use of a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a component represented by the following formula (2) Polyamines obtained from the diamine component of amines and polymers of at least one type of polyamidoimidized polymers and organic solvents, and the weight ratio of (Aa) and (Ab) is (Aa) : (Ab) = 55: 45 ~ 90: 10, preferably 60: 40 ~ 90: 10, more preferably 60: 40 ~ 85: 15.

In formula (1), i is 0 or 1, and X is a single bond, an ether bond, a carbonyl group, an ester bond, a phenylene group, a linear alkylene group having 1 to 20 carbon atoms, and a branch having 2 to 20 carbon atoms. Chain alkylene, cyclic alkylene having 3 to 12 carbon atoms, sulfofluorenyl group, amido bond, or a combination thereof, here, alkylene having 1 to 20 carbon atoms may be Interrupted by a bond selected from an ester bond and an ether bond, the carbon atoms of phenylene and alkylene may be selected from halogen atoms, cyano, alkyl, haloalkyl, alkoxy and haloalkoxy 1 or more of the same or different substituents.
Each constituent element is detailed below.

＜ (Aa) component ＞
The component (Aa) used in the liquid crystal alignment agent of the present invention is selected from polyamines obtained by using a tetracarboxylic dianhydride component containing a tetracarboxylic dianhydride represented by the above formula (1) and a diamine component, and A polymer of at least one kind of polyimide-fluorinated imidized polymer.

<Tetracarboxylic dianhydride component>
Examples of the tetracarboxylic dianhydride represented by the formula (1) include the following compounds, but they are not limited thereto. In the following formula, q represents an integer of 1 to 20.

Among the tetracarboxylic dianhydrides represented by the formula (1), from the viewpoint of easing the residual DC accumulated by the DC voltage, the formulae (1-1), (1-2), and (1-3) are preferable. , (1-4), (1-5), (1-7), from the viewpoint of stable supply, the above formulae (1-1) and (1-5) are particularly preferred.

In the component (A-a), the amount of the tetracarboxylic dianhydride represented by the formula (1) occupied by the entire tetracarboxylic dianhydride component is too small, and the effect of the present invention cannot be obtained. Therefore, the amount of the tetracarboxylic dianhydride represented by the formula (1) is preferably 30 to 100 mol%, more preferably 50 to mol of the total tetracarboxylic dianhydride used for the production of the component (Aa). ~ 100 mole%, and more preferably 70 ~ 100 mole%.

The tetracarboxylic dianhydride represented by the formula (1) may be used singly or in combination. In this case, the total amount of the tetracarboxylic dianhydride represented by the formula (1) is preferably the above-mentioned preferable amount.

＜ Diamine component ＞
As the diamine component for producing the (Aa) component of the present invention, a diamine represented by the following formula (5) can be used.

W ² in formula (5) is a divalent organic group, and its structure is not particularly limited, and two or more kinds may be mixed. Specific examples thereof include structures represented by the following formulas [W ² -1] to [W ² -152]. R ₁ and R ₂ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group.

Among them, from the viewpoint of easing the residual DC accumulated by the DC voltage, W2-7, W2-8, W2-20, W2-21, W2-23, W2-24, W2-26, and W2-40 are preferred. , W2-41, W2-49, W2-51, W2-65, W2-67, W2-68, W2-69, W2-70, W2-71, W2-142, W2-144, W2-148, W2 -151, more preferably W2-65, W2-67, W2-68, W2-69, W2-70, W2-71, W2-142, W2-144, W2-148, W2-151.

＜ (Ab) component ＞
The component (Ab) used in the liquid crystal alignment agent of the present invention is selected from the group consisting of a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine component containing a diamine represented by the above formula (2). Polyamidic acid and at least one type of polymer of the polyamidic acid imidized polymer.

The specific aliphatic tetracarboxylic dianhydride used in the present invention includes a tetracarboxylic dianhydride represented by the following formula (3). In the formula, X ₁ is any _one of the following (X-1) to (X-28).

In the formula (X-1), R ₃ to R ₆ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, and more preferably a hydrogen atom or a methyl group.

Among the above, from the viewpoint of photo-alignment, the most preferable is (X-1). In (X-1), R ₃ and R ₅ are methyl groups, R ₄ and R ₆ are hydrogen atoms, and R ₃ ~ The structure in which R ₆ is a hydrogen atom is preferable, and among them, a structure in which R ₃ to R ₆ are hydrogen atoms is particularly preferable.

In the component (A-b), when the amount of the aliphatic acid dianhydride occupied by the entire tetracarboxylic dianhydride component is too small, the effect of the present invention cannot be obtained. Therefore, the amount of the aliphatic tetracarboxylic dianhydride is preferably 50 to 100 mol%, and more preferably 60 to 100 mol, relative to 1 mol of the all-tetracarboxylic dianhydride used in the production of the (Ab) component. Ear%, and more preferably 80 to 100 mole%.

The proportion of the diamine represented by the formula (2) in the polyamidic acid and polyamidoimidized polymer of the (Ab) component of the present invention is relative to the total diamine used in the production of the (Ab) component 1 mole, preferably 10 to 100 mole%, more preferably 30 to 100 mole%, and even more preferably 50 to 100 mole%.

In addition to the diamine represented by the above formula (2), the polyamidic acid and the polyamidoimidized polymer of the (Ab) component contained in the liquid crystal alignment agent of the present invention can also use the above formula (5) ).

In the polyamidic acid and the polyamidoimidized polymer of the (Ab) component contained in the liquid crystal alignment agent of the present invention, when the proportion of the diamine represented by the formula (5) is increased, the present invention may be damaged. The effect of the invention is not good. Therefore, the proportion of the diamine represented by formula (5) is 1 mole relative to the total diamine, preferably 0 to 90 mole%, more preferably 0 to 70 mole%, and even more preferably 0 to 50 moles. ear%.

＜ Method for producing polyamic acid ＞
The polyamido acid of the polyamido precursor used in the present invention can be synthesized by the method shown below.
Specifically, by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent, the reaction can be performed at -20 to 150 ° C, preferably 0 to 70 ° C, for 30 minutes to 24 hours, preferably 1 to 12 hours to synthesize.
The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. in terms of the solubility of the monomers and polymers. They can be used singly or in combination of two or more.
The concentration of the polymer is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass from the viewpoint that the polymer is not easily precipitated and a high molecular weight body can be obtained.
The polyamic acid obtained as described above can be precipitated and recovered by injecting a weak solvent while thoroughly stirring the reaction solution. Further, after performing precipitation several times, washing with a weak solvent, and drying at room temperature or heating, a purified polyamic acid powder can be obtained. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, and the like, and water, methanol, ethanol, and 2-propanol are preferred.

＜ Manufacturing method of polyimide ＞
The polyimide used in the present invention can be produced by subjecting the aforementioned polyamidic acid to amidine.
When a polyfluorene imide is produced from a polyamic acid, it is simple to add a chemical chemical fluorimide to the aforementioned polyfluorine solution obtained by the reaction of a diamine component and a tetracarboxylic dianhydride. The chemical fluorene imidization is preferably carried out at a relatively low temperature. In the process of fluorene imidization, it is not easy to reduce the molecular weight of the polymer, so it is preferable.
Chemical ammonium imidization can be carried out by stirring the polymer to be imidized in an organic solvent, in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferred because it has a suitable basicity for the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic dianhydride. Among them, when acetic anhydride is used, purification after the reaction is facilitated, so it is preferable.
The temperature at which the amidine imidization reaction is performed is -20 to 140 ° C, preferably 0 to 100 ° C, and the reaction time is 1 to 100 hours. The amount of basic catalyst is 0.5 to 30 times moles of polyamino acid group, preferably 2 to 20 times moles, and the amount of acid anhydride is 1 to 50 times mole of polyamino acid group, preferably 3 to 30 times Mor. The hydrazone imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.
The added catalyst and the like remain in the solution after the polyimide imidization reaction. Therefore, the obtained imidimide polymer is recovered by the following means and re-dissolved with an organic solvent as the liquid crystal alignment of the present invention. Agent is better.

The solution of the polyimide obtained as described above can be precipitated by pouring a weak solvent into the solution while stirring sufficiently. After carrying out precipitation several times, washing with a weak solvent, and drying at normal temperature or heating, a purified polymer powder can be obtained.
The weak solvent is not particularly limited, and examples thereof include methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene. Preferred are methanol, ethanol, 2-propanol, acetone and the like.

The weight ratio of (Aa) component and (Ab) component manufactured in this way is (Aa): (Ab) = 55: 45 ~ 90: 10, preferably 60: 40 ~ 90: 10, more preferably 60: 40 ~ At 85:15, the invention effect can be exerted. That is, in the above range, the residual DC accumulated by the direct current is relaxed quickly, and the liquid crystal alignment stability is excellent, so the residual image characteristics are excellent.

The polyimide precursor used in the present invention can be obtained by reacting a diamine component with a tetracarboxylic acid derivative, and examples thereof include polyamic acid or polyamidate.

＜ Production of Polyimide Precursor-Polyamic Acid ＞
The method for producing a polyamic acid according to the components (Aa) and (Ab).

＜ Production of Polyimide Precursor-Polyamidate ＞
The polyamidate precursor of the polyamidoimide precursor used in the present invention can be produced by the production method of (1), (2) or (3) shown below.

(1) When it is made from a polyamic acid A polyamic acid ester can be manufactured by esterifying the polyamic acid manufactured as mentioned above. Specifically, by reacting polyamic acid and an esterifying agent in the presence of an organic solvent at a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, the reaction is performed for 30 minutes to 24 hours, preferably Made in 1 ~ 4 hours.
The esterifying agent is preferably one which can be easily removed by purification, and examples thereof include N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide di neopentylbutyl acetal, N, N-dimethylformamide di-t-butyl acetal Aldehyde, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4- ( 4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylchloromorpholine and the like. The addition amount of the esterifying agent is 1 mol, and preferably 2 to 6 mol equivalents relative to the repeating unit of the polyamic acid.

Examples of the organic solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N, N-dimethylformamidine, N, N-dimethylacetamidine Amine, dimethylsulfinium or 1,3-dimethyl-imidazolinone. When the solvent solubility of the polyfluorene imide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formula [ D-1] ~ solvent represented by formula [D-3].
These solvents may be used singly or in combination. Moreover, even if it is a solvent which does not melt | dissolve a polyfluorene imide precursor, in the range which does not precipitate the produced polyfluorene imide precursor, you may mix and use it with the said solvent. In addition, the water in the solvent will hinder the polymerization reaction and cause hydrolysis of the produced polyimide precursor. Therefore, it is preferable to use a solvent for dehydration and drying.
The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in terms of the solubility of the polymer, and one of these can be used Or mix two or more types. The concentration at the time of production is such that the precipitation of the polymer is difficult to occur and a high-molecular-weight body can be easily obtained, and is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass.

(2) When manufactured by the reaction of a tetracarboxylic acid diester dichloride and a diamine Polyurethane can be manufactured from a tetracarboxylic acid diester dichloride and a diamine.
Specifically, the reaction can be performed at a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, by reacting a tetracarboxylic acid diester dichloride and a diamine in the presence of a base and an organic solvent for 30 minutes. It takes about 24 hours, preferably 1 to 4 hours.
As the base, pyridine, triethylamine, 4-dimethylaminopyridine, or the like can be used, but pyridine is preferably used to allow the reaction to proceed steadily. The amount of the base added is an amount that can be easily removed and a high-molecular-weight body can be easily obtained. It is preferably 2 to 4 times the mole of the tetracarboxylic acid diester dichloride.
The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in terms of the solubility of the monomers and polymers. These solvents may be used alone or in combination of two or more. use. The polymer concentration at the time of production is less likely to cause precipitation of the polymer and it is easy to obtain a high molecular weight body, and is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, it is preferable that the solvent used in the production of the polyamic acid ester is dehydrated as much as possible, and it is better to prevent the outside air from being mixed in a nitrogen environment.

(3) When it is produced from a tetracarboxylic acid diester and a diamine A polyamidate can be produced by polycondensation of a tetracarboxylic acid diester and a diamine.
Specifically, a tetracarboxylic diester and a diamine can be reacted in the presence of a condensing agent, a base, and an organic solvent at a temperature of 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C, for 30 minutes to 24 minutes. It is preferably produced in 3 to 15 hours.
The condensing agent may be used triphenyl phosphite, dicyclohexyl carbodiimide (carbodiimide), 1- ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N , N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholine, O- (benzotriazol-1-yl) -N, N, N ', N'- Tetramethylurea tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethylmethylurea hexafluorophosphate, (2,3-dihydro 2-thioxo-3-benzoxazolyl) phosphonic acid diphenyl ester and the like. The addition amount of the condensing agent is preferably 2 to 3 times the mole of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the alkali added is an amount that can be easily removed and a high-molecular-weight body can be easily obtained. It is preferably 2 to 4 times the mole of the diamine component.
In the above reaction, the reaction is efficiently performed by adding a Lewis acid as an additive. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The addition amount of the Lewis acid is preferably from 0 to 1.0 times the mole of the diamine component.
Among the above-mentioned three production methods of polyamic acid esters, in order to obtain a high-molecular-weight polyphosphoric acid esters, the production method of (1) or (2) above is particularly preferred.
The polymer solution obtained as described above can be precipitated by pouring the polymer into a weak solvent while stirring sufficiently. After carrying out precipitation several times, washing with a weak solvent, and drying at room temperature or heating, a purified polyamidate powder can be obtained. The weak solvent is not particularly limited, but examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

＜ Liquid crystal alignment agent ＞
The liquid crystal alignment agent used in the present invention has a form of a solution in which a polymer component is dissolved in an organic solvent. The molecular weight of the polymer is expressed as a weight average molecular weight, preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000. The number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.
The concentration of the polymer of the liquid crystal alignment agent used in the present invention can be appropriately changed by setting the thickness of the coating film to be formed, but from the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more. From the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. The concentration of the particularly good polymer is 2 to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent used in the present invention is not particularly limited when the polymer component is uniformly dissolved. Specific examples include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl 2-Pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethylsulfinium, dimethylfluorene, γ-butyrolactone, 1,3-dimethyl -Imidazolinone, 3-methoxy-N, N-dimethylpropanamide and the like. These can be used singly or in combination of two or more kinds. Moreover, even if it is a solvent which does not dissolve a polymer component uniformly, if it is the range in which a polymer does not precipitate, it can mix with the said organic solvent.

In addition to the organic solvents contained in the liquid crystal alignment agent, in addition to the solvents described above, a mixed solvent in which the applicability when applying the liquid crystal alignment agent or a solvent which improves the surface smoothness of the coating film is generally used, and the liquid crystal of the present invention Among the alignment agents, such a mixed solvent is also suitable. Specific examples of the organic solvent used in combination include the following, but they are not limited to these examples.
Examples include ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1 -Butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol Alcohol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol , 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2,6-dimethyl-4-heptanol, 1,2-ethylene glycol, 1,2- Propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2- Methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl Ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2 -Pentanone, diethylene glycol methyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2,6-dione Methyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol Alcohol diacetate, propylene carbonate, vinyl carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (Hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol Monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate Ester, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2 -(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, lactic acid Ethyl acetate, methyl acetate, ethyl acetate, n-butyl acetate, ethyl acetate Propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-methyl Ethoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate , N-propyl lactate, n-butyl lactate, isoamyl lactate, solvents represented by the following formulas [D-1] to [D-3], and the like.

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

Among the preferred solvents, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, and N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether can be listed. , N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether , N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol Monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanol, N-methyl-2-pyrrolidone With γ-butyrolactone and dipropylene glycol dimethyl ether. The type and content of this solvent can be appropriately selected according to the coating device, coating conditions, and coating environment of the liquid crystal alignment agent.

In addition, in the liquid crystal alignment agent of the present invention, in order to improve the mechanical strength of the film, the following additives may be added.

These additives are preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. When it is less than 0.1 parts by mass, the effect cannot be expected, and when it exceeds 30 parts by mass, the alignment of the liquid crystal is reduced, so it is more preferably 0.5 to 20 parts by mass.
In the liquid crystal alignment agent of the present invention, in addition to the above, as long as the effect of the present invention is not impaired, polymers other than polymers may be added to change the electrical characteristics such as the dielectric constant or conductivity of the liquid crystal alignment film. Purpose dielectric or conductive substance, purpose silane coupling agent for improving adhesion between liquid crystal alignment film and substrate, purpose cross-linking compound for improving hardness or density of film when forming liquid crystal alignment film, and coating film During firing, a perylene imidation accelerator and the like for the purpose of arylene imidation of polyamic acid are efficiently performed.

<Liquid crystal alignment film> and <Manufacturing method of liquid crystal alignment film>
The liquid crystal alignment film of the present invention is a film obtained by coating the liquid crystal alignment agent on a substrate and drying and firing the substrate. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, or a polycarbonate substrate can be used. From the viewpoint of simplification of the process, it is preferable to use a substrate formed with an ITO (Indium Tin Oxide) electrode or the like for liquid crystal driving. In addition, when the reflective liquid crystal display element is a single-sided substrate, an opaque material such as a silicon wafer may be used, and in this case, an electrode that uses light reflecting material such as aluminum may also be used.

Examples of the method for applying the liquid crystal alignment agent of the present invention include a spin coating method, a printing method, and an inkjet method. The steps of drying and firing after applying the liquid crystal alignment agent of the present invention can be selected at any temperature and time. Generally, in order to sufficiently remove the organic solvent contained, drying is performed at 50 ° C to 120 ° C for 1 minute to 10 minutes, and then, firing is performed at 150 ° C to 300 ° C for 5 to 120 minutes. The thickness of the coating film after firing is not particularly limited. When the thickness is too thin, the reliability of the liquid crystal display element may be reduced, so it is 5 to 300 nm, preferably 10 to 200 nm.

Examples of a method for subjecting the obtained liquid crystal alignment film to an alignment treatment include a rubbing method and a photo-alignment treatment method.
The friction treatment can be performed using an existing friction device. Examples of the material of the friction cloth at this time include cotton, nylon, and rayon. The conditions for the rubbing treatment are generally the conditions of a rotation speed of 300 to 2000 rpm, a conveying speed of 5 to 100 mm / s, and a pushing amount of 0.1 to 1.0 mm. Then, using pure water, alcohol, or the like, the residue caused by friction is removed by ultrasonic cleaning.

Specific examples of the photo-alignment treatment method include a method in which the surface of the coating film is irradiated with radiation ray polarized in a specific direction, and may be subjected to a heat treatment at a temperature of 150 to 250 ° C. to give the liquid crystal alignment ability. As the radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 nm to 400 nm are preferred, and ultraviolet rays having a wavelength of 200 nm to 400 nm are particularly preferred. In addition, in order to improve the alignment of the liquid crystal, the coating film substrate may be heated at 50 to 250 ° C. while being irradiated with radiation. The radiation dose is preferably 1 to 10,000 mJ / cm ² , and particularly preferably 100 to 5,000 mJ / cm ² . The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a specific direction.
The higher the extinction ratio of polarized ultraviolet light, the more anisotropy can be imparted, so it is preferable. Specifically, the extinction ratio of the linearly polarized ultraviolet rays is preferably 10: 1 or more, and more preferably 20: 1 or more.

The film irradiated with the polarized radiation may be contact-treated with a solvent including at least one selected from water and an organic solvent.
The solvent used for the contact treatment is not particularly limited as long as it is a solvent capable of dissolving a decomposed product generated by light irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, and butyl cellosolve. Agents, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. These solvents may be used in combination of two or more.

From the viewpoint of general versatility or safety, it is more preferably at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate. Particularly preferred are water, 2-propanol, and a mixed solvent of water and 2-propanol.
In the present invention, the contact treatment of the film irradiated with the radiation of polarized light and the solution containing the solvent is performed by a treatment such as a dipping treatment, a spray treatment, or the like, in which the film and the solution are preferably brought into full and sufficient contact. Among them, the method of performing the dipping treatment on the film in a solution containing an organic solvent is preferably 10 seconds to 1 hour, and more preferably 1 to 30 minutes. The contact treatment may be performed at normal temperature or heating, but it is preferably performed at 10 to 80 ° C, and more preferably at 20 to 50 ° C. Further, if necessary, means for improving the contact such as ultrasonic waves can be implemented.
After the above contact treatment, in order to remove the organic solvent in the used solution, it may be washed (washed) or dried with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone and the like. Either or both.

In addition, for a film subjected to a contact treatment with the above-mentioned solvent, in order to dry the solvent and reorient the molecular chains in the film, the film can be heated at 150 ° C or higher.
The heating temperature is preferably 150 to 300 ° C. The higher the temperature, the better the realignment of the molecular chains, but when the temperature is too high, there is a concern that the molecular chains are decomposed. Therefore, the heating temperature is more preferably 180 to 250 ° C, and particularly preferably 200 to 230 ° C.
When the heating time is too short, the effect of realignment of the molecular chain may not be obtained. When the heating time is too long, the molecular chain may be decomposed. Therefore, it is preferably 10 seconds to 30 minutes, and more preferably 1 minute to 10 minutes.

The method for manufacturing a substrate having the liquid crystal alignment film of the present invention is preferably one including the following steps [I] to [IV].
It has [I] a polyamic acid containing (Aa) selected from the group consisting of a polyamic acid obtained by using a tetracarboxylic dianhydride component containing a tetracarboxylic dianhydride represented by formula (1) and a diamine component, and the polyamic acid (Ab) is a polymer selected from the group consisting of a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride and a diamine containing a diamine represented by formula (2). A polyamic acid obtained from the ingredients and at least one kind of polymer of the polyimide-fluorinated polymer and a liquid crystal alignment agent of an organic solvent are coated on a substrate having a conductive film for driving a transverse electric field, Forming a coating film;
[II] a step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and
[III] A step of heating the coating film obtained in [II].
According to the above steps, a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element to which alignment control ability is provided can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

In addition to the substrate (first substrate) obtained as described above, by preparing a second substrate, a lateral electric field drive type liquid crystal display element can be obtained.
The second substrate is a substrate instead of a conductive film for driving a transverse electric field. In addition to using a substrate without a conductive film for driving a transverse electric field, the above-mentioned steps [I] to [III] are used (due to use without a transverse electric field The substrate of the conductive film for driving is convenient. In the present invention, it may be simply referred to as steps [I '] to [III']), and a second substrate having a liquid crystal alignment film provided with an alignment control capability may be obtained.

A method for manufacturing a transverse electric field-driven liquid crystal display element is to have [IV] the liquid crystal alignment films of the first and second substrates facing each other via the liquid crystal, and the first and second substrates obtained as described above to be arranged to face each other to obtain a liquid crystal display element step. Thereby, a transverse electric field drive type liquid crystal display element can be obtained.

Hereinafter, each step of [I] to [III] and [IV] included in the manufacturing method of the present invention will be described.

＜ Step [I] ＞
In step [I], a substrate containing a conductive film for driving a transverse electric field is coated with a polymer composition containing a photosensitive main polymer and an organic solvent to form a coating film.

<Substrate>
The substrate is not particularly limited. When the manufactured liquid crystal display element is a transmissive type, it is preferable to use a substrate having high transparency. In this case, it is not particularly limited, and a glass substrate, a plastic substrate such as an acrylic substrate, a polycarbonate substrate, or the like can be used.
Further, it is considered to be used for a reflective liquid crystal display element, and an opaque substrate such as a silicon wafer may be used.

＜ Conductive film for driving transverse electric field ＞
The substrate has a conductive film for driving a transverse electric field.
When the liquid crystal display element is a transmissive type, examples of the conductive film include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and the like, but it is not limited thereto.
In the case of a reflective liquid crystal display device, the conductive film can be exemplified by a material that reflects light, such as aluminum, but is not limited thereto.
As a method for forming a conductive film on a substrate, a conventionally known method can be used.

The coating method for coating the polymer composition on a substrate having a conductive film for driving a transverse electric field is not particularly limited.
The coating method is generally industrially performed by screen printing, lithography, flexo printing, or inkjet. Other coating methods include a dipping method, a roll coating method, a slit coating method, a spin coater method (spin coating method), or a spray method, and these methods can be used in accordance with the purpose.

After the polymer composition is coated on a substrate having a conductive film for driving a transverse electric field, it is preferably heated at a temperature of 50 to 300 ° C by a heating means such as a hot plate, a thermal cycle oven, or an IR (infrared) oven. The solvent was evaporated at 50 to 180 ° C to obtain a coating film. The drying temperature at this time is preferably lower than the step [III] from the viewpoint of liquid crystal alignment stability.
When the thickness of the coating film is too thick, the power consumption of the liquid crystal display element is disadvantageous. When the thickness of the coating film is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferably 5 nm to 300 nm, and more preferably 10 nm to 150 nm.
Furthermore, a step of cooling the substrate on which the coating film is formed to room temperature may be provided after the step [I] and before the step [II].

＜ Step [II] ＞
Step [II] is irradiating the coating film obtained in step [I] with polarized ultraviolet rays. When the film surface of the coating film is irradiated with polarized ultraviolet rays, the substrate is irradiated with polarized ultraviolet rays through a polarizing plate from a specific direction. The ultraviolet rays used can be ultraviolet rays having a wavelength in the range of 100nm to 400nm. It is preferable to select an optimal wavelength through a filter or the like depending on the type of the coating film to be used. In addition, for example, in order to selectively cause a photodecomposition reaction, ultraviolet rays having a wavelength in a range of 240 nm to 400 nm can be selected to be used. As the ultraviolet rays, for example, light emitted from a high-pressure mercury lamp or a metal halide lamp can be used.

The amount of polarized ultraviolet radiation depends on the coating film used. The exposure amount is one of the maximum polarized ultraviolet rays (hereinafter also referred to as ΔAmax) of the polarized ultraviolet ray (hereinafter also referred to as ΔAmax) in the coating film that can achieve the maximum UV absorbance in the direction parallel to the polarization direction of the polarized ultraviolet rays and the ultraviolet absorbance in the vertical direction. The range of% ~ 70% is preferable, and the range of 1% ~ 50% is more preferable.

＜ Step [III] ＞
Step [III] is performed by heating the polarized ultraviolet coating film in step [II]. By heating, the orientation control ability of the coating film can be imparted.
For heating, heating means such as a hot plate, a thermal cycle type oven, or an IR (infrared) type oven can be used. The heating temperature is determined in consideration of the temperature at which the coating film used exhibits good liquid crystal alignment stability and electrical characteristics.

The heating temperature is preferably a temperature range in which the main chain polymer exhibits good liquid crystal alignment stability. When the heating temperature is too low, the anisotropic width effect or thermal imidization caused by heat tends to be inadequate, and when the heating temperature is too high compared to the above temperature range, polarization exposure is given. The anisotropy tends to disappear. At this time, it is sometimes difficult to reorient in one direction by self-organization.

The thickness of the coating film formed after heating is the same as that described in step [I], and is preferably 5 nm to 300 nm, and more preferably 50 nm to 150 nm.
With the above steps, the manufacturing method of the present invention can achieve an efficient introduction of anisotropy into a coating film. In addition, a substrate with a liquid crystal alignment film can be manufactured efficiently.

＜ Step [IV] ＞
Step [IV] is a method of obtaining the substrate (first substrate) having a liquid crystal alignment film on the conductive film for driving a transverse electric field obtained in step [III], and the same as obtained in steps [I '] to [III']. A substrate (second substrate) with a liquid crystal alignment film without a conductive film, the liquid crystal alignment films of both sides are arranged opposite to each other via liquid crystal, and a liquid crystal cell is produced by a conventional method, and a lateral electric field drive type liquid crystal display element is produced. A step of.
Steps [I '] to [III'] are performed in step [I], in place of a substrate having a conductive film for lateral electric field drive, and using a substrate without the conductive film for lateral electric field drive, and step [ I] ~ [III] do the same. The difference between steps [I] to [III] and steps [I '] to [III'] is only the presence or absence of the above-mentioned conductive film, so the description of steps [I '] to [III'] is omitted.

<Liquid crystal display element>
The liquid crystal display element of the present invention is obtained by using the liquid crystal alignment agent of the present invention through the aforementioned liquid crystal alignment film manufacturing method to obtain a substrate with a liquid crystal alignment film, and then preparing a liquid crystal cell by a conventional method, and using the liquid crystal cell as a liquid crystal display element. .
As an example of a method for manufacturing a liquid crystal cell, for example, a liquid crystal display element having a passive matrix structure will be described as an example. Moreover, it may be a liquid crystal display element having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display.
First, a transparent glass substrate is prepared. A common electrode is provided on one of the substrates, and a segment electrode is provided on the other substrate. These electrodes can be patterned, for example, as ITO electrodes to display a desired image. Next, an insulating film is provided on each substrate to cover the common electrode and the segment electrode. The insulating film may be, for example, a film made of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, the liquid crystal alignment film of the present invention is formed on each substrate by the above method.
The alignment film surfaces of one of the substrates and the other substrate overlap each other, and the periphery is adhered with a sealing material. In order to control the substrate gap in the sealing material, a spacer is usually mixed. Further, it is preferable that a spacer for controlling the substrate gap is also scattered on the in-plane portion where the sealing material is not provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.
Next, a liquid crystal material is injected into a space surrounded by the two substrates and the sealing material through an opening portion provided in the sealing material. Then, this opening is sealed with an adhesive. In the injection, a vacuum injection method may be used, or a method using a capillary phenomenon in the atmosphere may be used. Next, a polarizing plate is provided. Specifically, a pair of polarizing plates are stuck on the surface opposite to the liquid crystal layer of two substrates. Through the above steps, the liquid crystal display element of the present invention can be obtained.

In the present invention, a resin having a reactive group such as an epoxy group, an acrylic fluorenyl group, a methacryl fluorenyl group, a hydroxyl group, an allyl group, an ethyl fluorenyl group, and the like can be used as the sealant and cured by irradiation with ultraviolet rays or heating. In particular, a hardening resin system using a reactive group having both an epoxy group and a (meth) acrylfluorenyl group is preferred.
In the sealing agent of the present invention, an inorganic filler may be blended for the purpose of improving adhesion and moisture resistance. The inorganic filler that can be used is not particularly limited, and specific examples include spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, boron nitride, Calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesia, zirconia, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, titanic acid Barium, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, Barium sulfate, calcium sulfate, mica, talc, clay, aluminum oxide, aluminum hydroxide, calcium silicate, aluminum silicate. The inorganic filler may be used in combination of two or more.

As described above, the substrate for a transverse electric field drive type liquid crystal display element manufactured using the polymer of the present invention or a transverse electric field drive type liquid crystal display element having the substrate exhibits excellent liquid crystal alignment stability with less polarized ultraviolet radiation. It is suitable for large-screen, high-definition liquid crystal televisions, etc. due to its relaxation characteristics with residual DC. In addition, the liquid crystal alignment film manufactured by the method of the present invention is excellent in reliability and can also be used for a variable phaser using liquid crystals. This variable phaser can be applied to, for example, an antenna having a variable resonance frequency.

[Example]

Examples are given below to describe the present invention more specifically, but the present invention is not limited to those examples. The abbreviations of the compounds and solvents are as follows.
NMP: N-methyl-2-pyrrolidone
BCS: Butyl Cellosolve
DA-1: Compound represented by the following structural formula (DA-1)
DA-2: Compound represented by the following structural formula (DA-2)
DA-3: Compound represented by the following structural formula (DA-3)
DA-4: Compound represented by the following structural formula (DA-4)
DA-5: Compound represented by the following structural formula (DA-5)
DA-6: Compound represented by the following structural formula (DA-6)
DA-7: Compound represented by the following structural formula (DA-7)
CA-1: Compound represented by the following structural formula (CA-1)
CA-2: Compound represented by the following structural formula (CA-2)
CA-3: Compound represented by the following structural formula (CA-3)
CA-4: Compound represented by the following structural formula (CA-4)

＜ Measurement of viscosity ＞
In the synthesis example, the viscosity of the polymer solution was an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a tapered rotor TE-1 (1 ° 34 ', R24), and a temperature of 25 ° C. Take measurements.

<Synthesis example 1>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-1 (2.18 g (5.40 mmol)) and DA-2 (3.43 g (12.6 mmol)), add 55.8 g of NMP, and feed Disperse with stirring under nitrogen. CA-1 (3.25g (16.6mmol)) was added to this diamine solution while stirring under water cooling, and 23.9g of NMP was added, and the mixture was stirred at 23 ° C for 5 hours under a nitrogen atmosphere to obtain polyamic acid-polyfluorene imine. Copolymer solution. The viscosity of the polyamido-polyamidoimine copolymer solution at a temperature of 25 ° C was 178 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 30.2 g of the polyamic acid-polyimide copolymer solution, add 16.8 g of NMP and 20.1 g of BCS, and stir with a magnetic stirrer (Magnetic Stirrer) For 2 hours, a liquid crystal alignment agent (A-1) was obtained.

<Synthesis example 2>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-1 (5.10 g (12.6 mmol)) and DA-3 (1.32 g (5.40 mmol)), and add 61.8 g of NMP. Disperse with stirring under nitrogen. CA-1 (2.19g (11.2mmol)) and CA-2 (1.21g (5.40mmol)) were added to this diamine solution while stirring under water cooling, and 26.5g of NMP was added. The mixture was stirred at 40 ° C for 6 hours under a nitrogen atmosphere. To obtain a solution of a polyamidic acid-polyamidoimine copolymer. The viscosity of the polyamic acid-polyfluorene imine copolymer solution at a temperature of 25 ° C was 193 mPa · s.
In a 100-mL Erlenmeyer flask with a stirrer, weigh 31.3 g of the polyamic acid-polyimide copolymer solution, add NMP 17.4 g and BCS 20.9 g, and stir with a magnetic stirrer for 2 hours to obtain Liquid crystal alignment agent (A-2).

<Synthesis example 3>
In a 100-mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-4 (2.79 g (14.0 mmol)) and DA-3 (1.47 g (6.00 mmol)) and add 50.5 g of NMP. Stir with nitrogen to dissolve. CA-3 (5.59 g (19.0 mmol)) was added to this diamine solution while stirring under water cooling, and 21.7 g of NMP was added. The mixture was stirred at 50 ° C. for 20 hours under a nitrogen atmosphere to obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25 ° C was 480 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 29.0 g of the polyamic acid solution, add NMP 25.1 g and BCS 23.2 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A- 3).

<Synthesis example 4>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-4 (3.19 g (16.0 mmol)) and DA-5 (0.433 g (4.00 mmol)), add 47.3 g of NMP, and send in Stir with nitrogen to dissolve. CA-3 (5.59 g (19.0 mmol)) was added to this diamine solution while stirring under water cooling, and 20.3 g of NMP was added. The solution was stirred at 50 ° C. for 20 hours under a nitrogen atmosphere to obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25 ° C was 455 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stirrer, weigh 30.7 g of the polyamic acid solution, add NMP 26.6 g and BCS 24.6 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-4 ).

<Synthesis example 5>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-4 (3.19 g (16.0 mmol)) and DA-6 (0.433 g (4.00 mmol)), add 47.3 g of NMP, and feed Stir with nitrogen to dissolve. CA-3 (5.59 g (19.0 mmol)) was added to this diamine solution while stirring under water cooling, and 20.3 g of NMP was added. The solution was stirred at 50 ° C. for 20 hours under a nitrogen atmosphere to obtain a solution of polyamic acid. The viscosity of the polyamic acid solution at a temperature of 25 ° C was 418 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 30.1 g of the polyamic acid solution, add NMP 26.1 g and BCS 24.1 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-5 ).

<Synthesis example 6>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-4 (3.19 g (16.0 mmol)) and DA-3 (0.977 g (4.00 mmol)), add 41.0 g of NMP, and send in Stir with nitrogen to dissolve. CA-1 (1.65g (8.40mmol)) was added to this diamine solution while stirring under water cooling. After stirring at 23 ° C under a nitrogen atmosphere for 4 hours, CA-4 (2.18g (10.0mmol)) was added, and then NMP was added. Under a nitrogen atmosphere, 17.6 g was stirred at 50 ° C. for 18 hours to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25 ° C was 246 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 29.7 g of the polyamic acid solution, add NMP 25.7 g and BCS 23.8 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-6 ).

<Synthesis example 7>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, DA-7 (3.97 g (20.0 mmol)) was weighed out, 49.1 g of NMP was added, and the solution was stirred while being fed into nitrogen to dissolve. CA-3 (5.59 g (19.0 mmol)) was added to this diamine solution while stirring under water cooling, and 21.0 g of NMP was added. The mixture was stirred at 50 ° C. for 20 hours under a nitrogen atmosphere to obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25 ° C was 376 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 30.4 g of the polyamic acid solution, add NMP 26.4 g and BCS 24.3 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (A-7 ).

<Synthesis example 8>
In a 50-mL Erlenmeyer flask equipped with a stirrer, 8.07 g of the liquid crystal alignment agent (A-1) obtained in Synthesis Example 1 and 12.1 g of the liquid crystal alignment agent (A-3) obtained in Synthesis Example 3 were weighed and magnetically stirred The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-8).

<Synthesis example 9>
In a 50-mL Erlenmeyer flask with a stir bar, weigh 8.12 g of the liquid crystal alignment agent (A-1) obtained in Synthesis Example 1 and 12.2 g of the liquid crystal alignment agent (A-4) obtained in Synthesis Example 4, and stir with magnetic force The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-9).

<Synthesis example 10>
In a 50-mL Erlenmeyer flask with a stir bar, weigh 8.21 g of the liquid crystal alignment agent (A-1) obtained in Synthesis Example 1 and 12.3 g of the liquid crystal alignment agent (A-5) obtained in Synthesis Example 5, and stir by magnetic force. The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-10).

<Synthesis example 11>
In a 50-mL Erlenmeyer flask equipped with a stirrer, 6.02 g of the liquid crystal alignment agent (A-2) obtained in Synthesis Example 2 and 14.0 g of the liquid crystal alignment agent (A-6) obtained in Synthesis Example 6 were weighed and magnetically stirred. The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-11).

<Synthesis example 12>
In a 50-mL Erlenmeyer flask equipped with a stirrer, 6.11 g of the liquid crystal alignment agent (A-2) obtained in Synthesis Example 2 and 14.3 g of the liquid crystal alignment agent (A-7) obtained in Synthesis Example 7 were weighed, and magnetically stirred The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-12).

<Synthesis example 13>
In a 50-mL Erlenmeyer flask with a stir bar, weigh 4.24 g of the liquid crystal alignment agent (A-1) obtained in Synthesis Example 1 and 16.96 g of the liquid crystal alignment agent (A-3) obtained in Synthesis Example 3, and stir by magnetic The device was stirred for 2 hours to obtain a liquid crystal alignment agent (A-13).

<Comparative Synthesis Example 1>
In a 100-mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh DA-1 (2.18 g (5.40 mmol)) and DA-2 (3.43 g (12.6 mmol)), and add 58.1 g of NMP. Disperse with stirring under nitrogen. CA-4 (3.61 g (16.6 mmol)) was added to this diamine solution while stirring under water cooling, and 24.9 g of NMP was added. The mixture was stirred at 50 ° C. for 18 hours under a nitrogen atmosphere to obtain a polyamic acid-polyfluorene imine copolymer. Of the solution. The viscosity of the polyamidic acid-polyamidoimide copolymer solution at a temperature of 25 ° C was 269 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 30.6 g of the polyamic acid-polyimide copolymer solution, add 17.0 g of NMP and 20.4 g of BCS, and stir with a magnetic stirrer for 2 hours to obtain Liquid crystal alignment agent (B-1).

<Comparative Synthesis Example 2>
In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, DA-7 (3.97 g (20.0 mmol)) was weighed out, 39.5 g of NMP was added, and the solution was stirred while being fed into nitrogen. CA-1 (3.73 g (19.0 mmol)) was added to this diamine solution while stirring under water cooling, and 16.9 g of NMP was further added, and the mixture was stirred at 23 ° C. for 4 hours under a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of the polyamidic acid solution at a temperature of 25 ° C was 265 mPa ･ s.
In a 100-mL Erlenmeyer flask with a stir bar, weigh 29.9 g of the polyamic acid solution, add NMP 25.9 g and BCS 23.9 g, and stir with a magnetic stirrer for 2 hours to obtain a liquid crystal alignment agent (B-2 ).

<Comparative Synthesis Example 3>
In a 50-mL Erlenmeyer flask equipped with a stir bar, 8.14 g of the liquid crystal alignment agent (B-1) obtained in Comparative Synthesis Example 1 and 12.2 g of the liquid crystal alignment agent (A-3) obtained in Synthesis Example 3 were weighed. The stirrer was stirred for 2 hours to obtain a liquid crystal alignment agent (B-3).

<Comparative Synthesis Example 4>
In a 50-mL Erlenmeyer flask with a stir bar, weigh 6.07 g of the liquid crystal alignment agent (A-2) obtained in Synthesis Example 2 and 14.2 g of the liquid crystal alignment agent (B-2) obtained in Comparative Synthesis Example 2. The stirrer was stirred for 2 hours to obtain a liquid crystal alignment agent (B-4).

<Comparative Synthesis Example 5>
In a 50-mL Erlenmeyer flask with a stir bar, weigh 10.1 g of the liquid crystal alignment agent (A-2) obtained in Synthesis Example 2 and 10.1 g of the liquid crystal alignment agent (A-7) obtained in Synthesis Example 7, and stir with magnetic force. The device was stirred for 2 hours to obtain a liquid crystal alignment agent (B-5).

<Production of liquid crystal cell for evaluation of liquid crystal alignment stability and relaxation characteristics of residual DC>
A method for producing a liquid crystal cell for evaluating the liquid crystal alignment stability and the relaxation characteristics of the residual DC is shown below.
A liquid crystal cell having a structure of a liquid crystal display element having an FFS method was produced. First, prepare a substrate with electrodes. The substrate was a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. An IZO electrode constituting a counter electrode of the first layer is formed on the entire substrate. On the counter electrode of the first layer, a SiN (silicon nitride) film formed as a second layer by a CVD method is formed. The SiN film of the second layer has a film thickness of 500 nm and has a function as an interlayer insulating film. On the SiN film of the second layer, a dentate pixel electrode formed by patterning the IZO film as the third layer is arranged, and two pixels of the first pixel and the second pixel are formed. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer is the same as the figure described in Japanese Patent Application Laid-Open No. 2014-77845 (Japanese Laid-Open Gazette), and has a 栉 -tooth shape made up of a plurality of 弯曲 -shaped electrode elements bent at the center portion of a plurality of arrays . The width of each electrode element in the lateral direction is 3 μm, and the interval between the electrode elements is 6 μm. The pixel electrode of each pixel is formed by plurally arranged "ㄑ" -shaped electrode elements bent at the central portion, so the shape of each pixel is not a rectangular shape, but is the same as the electrode element. The shape of the Chinese character "ㄑ". In addition, each pixel is divided into upper and lower sides with its central curved portion as a boundary, and has a first region on the upper side and a second region on the lower side.
When the first region and the second region of each pixel are compared, the formation direction of the electrode elements constituting their pixel electrodes is different. That is, when the direction in which the polarization plane of the polarized ultraviolet rays to be described later is projected onto the line of the substrate is taken as a reference, the electrode elements of the pixel electrode are formed at an angle (clockwise) of + 10 ° in the first region of the pixel. In the second region, the electrode elements of the pixel electrode are formed so as to form an angle (clockwise) of -10 °. In the first region and the second region of each pixel, the direction in which the liquid crystal rotates on the substrate surface (in-plane switching) caused by the voltage application between the pixel electrode and the counter electrode is mutually formed. The composition of the opposite direction.

Next, the liquid crystal alignment agents obtained in Synthesis Examples 8 to 12 and Comparative Synthesis Examples 3 to 4 were filtered with a 1.0 μm filter, and then each of the prepared electrode substrates was coated with a spin coater. Next, it was dried for 90 seconds on a hot plate set at 70 ° C. Next, an APL-L050121S1S-APW01 exposure device made by Oxtail Motor Co., Ltd. was used to irradiate the linearly polarized light with ultraviolet rays in a direction perpendicular to the substrate through a wavelength selection filter and a polarizing plate. At this time, the polarizing surface of the polarized ultraviolet rays is projected in the direction of the line division of the substrate, and the third-layer IZO dentate electrode is tilted in a direction of 10 ° to set the direction of the polarizing surface. Next, an IR (infrared) -type oven set at 230 ° C. was fired for 30 minutes to obtain a substrate having an agglomerated polyimide liquid crystal alignment film with a film thickness of 100 nm to which an alignment treatment was applied. In addition, the counter substrate was a glass substrate having a columnar spacer having a height of 4 μm, in which an ITO electrode was formed on the back surface. In the same manner as above, a substrate having a polyimide liquid crystal alignment film subjected to an alignment treatment was obtained. These two substrates with a liquid crystal alignment film are a group. On one of the substrates, a sealant is printed in the form of a residual liquid crystal injection port, and the other substrate faces the liquid crystal alignment film to face the polarizing surface of polarized ultraviolet rays. The directions of the line divisions projected on the substrate became parallel, and the bonding and crimping were performed. Then, the sealant was hardened, and an empty cell with a liquid crystal layer gap of 4 μm was produced. This empty cell was injected with a liquid crystal MLC-7026-100 (negative liquid crystal manufactured by Merck) by a reduced pressure injection method, and then the injection port was closed to obtain an FFS-type liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 ° C. for 30 minutes, and left at 23 ° C. for a while, and then used for evaluation of liquid crystal alignment stability and relaxation characteristics of residual DC.

＜ Evaluation of liquid crystal alignment stability ＞
Using the liquid crystal cell, an AC voltage having a frequency of 30 Hz and 14 VPP was applied for 96 hours in a constant temperature environment of 60 ° C. Then, a short-circuited state is formed between the pixel electrode and the counter electrode of the liquid crystal cell. In this state, it is left at 23 ° C. overnight.
After being placed, the liquid crystal cell is placed between two polarizing plates whose polarizing axes are orthogonally arranged. When no voltage is applied, the backlight is turned on, and the arrangement angle of the liquid crystal cell is adjusted to minimize the brightness of the penetrating light. Then, from the angle at which the second region of the first pixel becomes the darkest to the angle at which the first region becomes the darkest, the rotation angle when the liquid crystal cell is rotated is taken as the angle Δ. The second pixel is also the same, and the second region and the first region are compared to calculate the same angle Δ. In addition, an average value of the angle Δ values of the first pixel and the second pixel is calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of the liquid crystal cell is less than 0.4 °, it is defined as “good”, and when the value of the angle Δ is 0.4 ° or more, it is defined as “bad” and evaluated.
Also, the angle Δ of the liquid crystal alignment agent when stored at -20 ° C for 8 days is defined as Δ [1], and the angle of Δ when the liquid crystal alignment agent is stored at 23 ° C for 8 days is defined as Δ [2] , The degree of deterioration of the angle Δ due to storage at 23 ° C was calculated using the following calculation formula.

Degree of deterioration of angle Δ caused by storage at 23 ° C = Δ [2] ÷ Δ [1] × 100

When it is less than 150, it is defined as "good", and when it is 150 or more, it is defined as "bad" and evaluated.

＜ Evaluation of the relaxation characteristics of residual DC ＞
The above-mentioned liquid crystal cell is arranged between two polarizing plates whose polarizing axes are orthogonally arranged, so that the pixel electrode and the counter electrode are short-circuited to form the same potential, and the LED backlight is illuminated from below the two polarizing plates, and the two polarizing plates are The brightness of the transmitted light of the LED backlight measured above is minimized to adjust the angle of the liquid crystal cell.
Next, a rectangular wave having a frequency of 30 Hz was applied to the liquid crystal cell, and the VT characteristic (voltage-transmittance characteristic) at a temperature of 23 ° C. was measured to calculate an AC voltage having a relative transmittance of 23%. This AC voltage corresponds to a region where the brightness of the voltage changes greatly, so it is suitable to evaluate the residual DC through the brightness.

Secondly, at a temperature of 23 ° C, an AC voltage with a relative transmittance of 23% and a rectangular wave with a frequency of 30 Hz was applied for 5 minutes, and a DC voltage of +1.0 V was overlapped and driven for 30 minutes. Then, the DC voltage was cut off, and the AC voltage having a relative transmittance of 23% was applied, and only a rectangular wave having a frequency of 30 Hz was applied for 30 minutes.
The faster the accumulated charge is relaxed, the faster the charge accumulates on the liquid crystal cell when the DC voltage overlaps, so the relaxation characteristic of the residual DC is a state where the relative transmittance after the DC voltage overlaps becomes 30% or more, and the relative after 30 minutes To what extent was the transmittance reduced? That is, when the relative transmittance after the DC voltage overlaps for 30 minutes decreases to less than 29%, it is defined as "good", and when the relative transmittance is 29% or more, it is defined as "bad" for evaluation.

<Example 1>
Two types of the liquid crystal alignment agent (A-8) obtained in Synthesis Example 8 were stored at -20 ° C for 8 days and stored at 23 ° C for 8 days, and liquid crystal cells were prepared as described above. A high-pressure mercury lamp is used to irradiate polarized ultraviolet rays through a wavelength-selective filter: 240LCF and 254nm-type polarizers. The amount of polarized ultraviolet radiation was measured using a UVD-S254SB illuminance meter made by Oxtail Motor Co., Ltd., and the wavelength was changed at 200, 300, 400, 600, 900, 1500, and 2000 mJ / cm ² at a wavelength of 254 nm. Seven liquid crystal cells with different amounts of polarized ultraviolet radiation were produced.
As for the results of evaluating the liquid crystal alignment stability of these liquid crystal cells, the angle Δ is the optimum amount of polarized ultraviolet radiation of 300 mJ / cm ² , the angle Δ [1] is 0.18 °, and the angle Δ [2] is 0.19 °, and The degree of deterioration of the angle Δ due to storage at 23 ° C was 106, which was good.
In addition, before the evaluation of the alignment stability of the liquid crystal, the residual DC relaxation characteristics of the same amount of polarized ultraviolet radiation before evaluation were evaluated, and the relative transmittance after the DC voltage overlap for 30 minutes was good, which was good.

<Examples 2 to 6>
Except that the liquid crystal alignment agent obtained in Synthesis Examples 9 to 13 was used, the liquid crystal alignment stability and the relaxation characteristics of residual DC were evaluated in the same manner as in Example 1.

<Comparative Examples 1 to 3>
Except for using the liquid crystal alignment agent obtained in Comparative Synthesis Examples 3 to 5, the same method as in Example 1 was used to evaluate the liquid crystal alignment stability and the relaxation characteristics of residual DC.

The liquid crystal alignment agent used in Examples 1 to 6 and Comparative Examples 1 to 3 includes a liquid crystal alignment agent containing a polymer represented by (Aa), a liquid crystal alignment agent containing a polymer represented by (Ab), and (Aa) and ( Table 1 shows the respective weight percentages of the polymer liquid crystal alignment agent represented by Ab).
Table 2 shows the polarized ultraviolet irradiation amount when the angle Δ is optimal when using the liquid crystal alignment agent obtained in Examples 1 to 6 and Comparative Examples 1 to 3, evaluation results of liquid crystal alignment stability, and evaluation results of mitigating characteristics of residual DC. .

As shown in Table 2, in Examples 1 to 6, the angle Δ of the difference between the alignment azimuth angles before and after the AC drive was less than 0.4 °, which is good. The deterioration degree of the angle Δ when the liquid crystal alignment agent was stored at 23 ° C for 8 days was also good. It is less than 150, which is good. It is 300 mJ / cm ^{2 with a} small amount of polarized ultraviolet radiation. The angle Δ is the best. The relative transmittance of the residual voltage after the DC voltage overlap for 30 minutes is less than 29.0%, which is good. , Are good afterimage characteristics, so the display quality of the liquid crystal display element is excellent. However, in Comparative Examples 1 to 3, the degree of deterioration due to storage at an angle Δ, an angle Δ of 23 ° C., the amount of polarized ultraviolet radiation, and the relative transmittance after the DC voltage was overlapped for 30 minutes were all not good results.
Thus, it was confirmed that the liquid crystal display element manufactured by the method of the present invention exhibits very excellent afterimage characteristics.

[Industrial availability]

A substrate for a transverse electric field drive type liquid crystal display element manufactured using the polymer of the present invention or a transverse electric field drive type liquid crystal display element having the substrate can exhibit excellent liquid crystal alignment stability and residual DC with less polarized ultraviolet radiation. The relaxation characteristics are excellent in productivity and afterimage characteristics. Therefore, it is applicable to large-screen and high-definition liquid crystal televisions.

Claims (11)

A liquid crystal alignment agent containing (Aa) selected from the group consisting of the following formula (1) (in formula (1), i is 0 or 1, X is a single bond, ether bond, carbonyl group, ester bond, phenylene Straight chain alkylene group with 1 to 20 carbon atoms, branched chain alkylene group with 2 to 20 carbon atoms, cyclic alkylene group with 3 to 12 carbon atoms, sulfofluorenyl group, amido bond or other And other combinations. Here, the alkylene group having 1 to 20 carbon atoms may be interrupted by a bond selected from an ester bond and an ether bond, and the carbon atoms of the phenylene group and the alkylene group may be selected from Tetracarboxylic dianhydride component of tetracarboxylic dianhydride represented by halogen atom, cyano, alkyl, haloalkyl, alkoxy, and haloalkoxy substituted with one or more of the same or different substituents) (Ab) is selected from the group consisting of tetracarboxylic dicarboxylic acid containing aliphatic tetracarboxylic dianhydride At least one type of polymer of polyamic acid obtained from an anhydride component and a diamine component containing a diamine represented by the following formula (2) and a polyimide polymer of the polyamidic acid, and an organic solvent, ( Aa) and (Ab) weight Is (Aa) :( Ab) = 55: 45 ~ 90: 10, . For example, the liquid crystal alignment agent of claim 1, wherein 10 to 100 mole% of the tetracarboxylic dianhydride component of the aforementioned (A-a) is the tetracarboxylic dianhydride represented by the aforementioned formula (1). For example, the liquid crystal alignment agent of claim 1 or 2, wherein 10 to 100 mole% of the tetracarboxylic dianhydride component of the aforementioned (A-b) is an aliphatic tetracarboxylic dianhydride. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein 10 to 100 mole% of the diamine component of the aforementioned (A-b) is a diamine of formula (2). The liquid crystal alignment agent according to any one of claim 1 to claim 4, wherein the tetracarboxylic dianhydride represented by the aforementioned formula (1) is selected from pyromellitic dianhydride and 3,3 ', 4,4'- At least one type of biphenyltetracarboxylic dianhydride. The liquid crystal alignment agent according to any one of claim 1 to claim 5, wherein the aforementioned aliphatic tetracarboxylic dianhydride is cyclobutane tetracarboxylic dianhydride or 1,3-dimethylcyclobutane tetracarboxylic dianhydride anhydride. A method for manufacturing a substrate having a liquid crystal alignment film, which comprises the following steps [I] to [III] to obtain a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element to which alignment control ability is provided, [I] a step of applying the composition of any one of claims 1 to 6 on a substrate having a conductive film for driving a transverse electric field to form a coating film; [II] a step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and [III] A step of heating the coating film obtained in [II]. A substrate having a liquid crystal alignment film for a transverse electric field drive type liquid crystal display element, which is manufactured by the method according to claim 7. A transverse electric field drive type liquid crystal display element having a substrate as claimed in claim 8. A method for manufacturing a liquid crystal display element is to obtain a transverse electric field drive type liquid crystal display element by having the following steps. Steps for preparing a substrate (first substrate) as claimed in item 8; By having: [I '] coating the composition of any one of claims 1 to 6 on the second substrate to form a coating film; [II '] a step of irradiating the coating film obtained in [I'] with polarized ultraviolet rays; and [III '] a step of heating the coating film obtained in [II']; A step of obtaining a liquid crystal alignment film having an alignment control capability, and a step of obtaining a second substrate having the liquid crystal alignment film; and [IV] A step of obtaining the liquid crystal display element by facing the liquid crystal alignment films of the first and second substrates through liquid crystal, and arranging the first and second substrates in an opposite direction. A transverse electric field driving type liquid crystal display element is manufactured by the method as claimed in claim 10.