KR102635627B1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display device - Google Patents

Abstract

The present invention provides a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display device, which provides orientation control with high efficiency and is excellent in burn-in characteristics resulting from liquid crystal misalignment or residual DC, and a transverse electric field driven liquid crystal display having the substrate. Devices are provided. The present invention relates to a tetracarboxylic dianhydride containing (Aa) tetracarboxylic dianhydride represented by the following formula (1) (in formula (1), i is 0 or 1, and X is a single bond, an ether bond, etc.) At least one type of polymer selected from polyamic acids obtained by using a carboxylic acid dianhydride component and a diamine component and imidized polymers of the polyamic acid, (Ab) tetracarboxylic acid 2 containing aliphatic tetracarboxylic acid dianhydride It contains at least one type of polymer selected from a polyamic acid obtained by using an anhydride component and a diamine component containing a diamine represented by the following formula (2) and an imidized polymer of the polyamic acid, and an organic solvent, (Aa) and A liquid crystal aligning agent is provided in which the weight ratio of (Ab) is (Aa):(Ab)=55:45 to 90:10.

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device for manufacturing a liquid crystal display device with excellent burn-in characteristics.

Liquid crystal display elements are known as light-weight, thin, and low-power-consumption display devices, and have recently made remarkable progress, including being used in large-sized television applications. A liquid crystal display element is configured, for example, by sandwiching a liquid crystal layer with a pair of transparent substrates provided with electrodes. And in a liquid crystal display element, an organic film made of an organic material is used as a liquid crystal alignment film so that the liquid crystal is in a desired state of alignment between substrates.

That is, the liquid crystal alignment film is a structural member of the liquid crystal display element, and is formed on the surface in contact with the liquid crystal of the substrate holding the liquid crystal, and plays a role of aligning the liquid crystal in a certain direction between the substrates. And the liquid crystal alignment film may be required to have a role of controlling the pretilt angle of the liquid crystal in addition to the role of aligning the liquid crystal in a certain direction, such as a direction parallel to the substrate, for example. The ability to control the orientation of the liquid crystal in such a liquid crystal aligning film (hereinafter referred to as orientation control ability) is provided by performing an orientation treatment on the organic film constituting the liquid crystal aligning film.

As an orientation treatment method for a liquid crystal alignment film for providing orientation control ability, the rubbing method has conventionally been known.

However, the rubbing method of rubbing the surface of a liquid crystal alignment film made of polyimide or the like sometimes has problems with generation of oscillation or static electricity. In addition, due to the recent high-definition of liquid crystal display elements and the irregularities caused by the electrodes on the corresponding substrate or the switching active elements for driving the liquid crystal, the surface of the liquid crystal alignment film cannot be rubbed uniformly with a cloth, making it impossible to achieve uniform liquid crystal orientation. There were cases where there were none.

Therefore, the photo-alignment method is being actively studied as another alignment treatment method for the liquid crystal alignment film without rubbing. There are various methods for photo-alignment. Anisotropy is formed in the organic film constituting the liquid crystal alignment film using linearly polarized light or collimated light, and the liquid crystal is aligned according to the anisotropy.

As the main photo-alignment method, a decomposition-type photo-alignment method is known. For example, a polyimide film is irradiated with polarized ultraviolet rays, and anisotropic decomposition is generated using the polarization direction dependence of ultraviolet absorption of the molecular structure. Then, the liquid crystal is oriented by the polyimide remaining without decomposition (for example, refer to Patent Document 1).

In addition, photo-crosslinking type and photo-isomerization type photo-alignment methods are also known. For example, using polyvinyl cinnamate, polarized ultraviolet rays are irradiated to cause a dimerization reaction (crosslinking reaction) at the double bond portions of the two side chains parallel to the polarized light. Then, the liquid crystal is aligned in a direction perpendicular to the direction of polarization (for example, refer to Non-Patent Document 1). In addition, when a side chain type polymer having azobenzene in the side chain is used, polarized ultraviolet light is irradiated to cause an isomerization reaction in the azobenzene portion of the side chain parallel to the polarization, and the liquid crystal is oriented in the direction orthogonal to the polarization direction ( For example, see Non-Patent Document 2).

In addition, as a photo-alignment film that improves the afterimage characteristics due to alternating current drive, a method of using a polyamic acid prepared using a diamine containing a cyclobutane ring and an imide group is known (for example, Patent Documents 2, 3 and 4).

As in the above example, the alignment treatment method of the liquid crystal alignment film by the photo-alignment method does not require rubbing, and there is no concern about generation of oscillation or static electricity. And orientation processing can be performed also on the board|substrate of a liquid crystal display element whose surface has irregularities, and it becomes a method of orientation processing of a liquid crystal alignment film suitable for an industrial production process.

On the other hand, the transverse electric field type liquid crystal cell has excellent viewing angle characteristics, but since the electrode portion formed in the substrate is small, if the voltage retention of the liquid crystal alignment film is weak, sufficient voltage is not applied to the liquid crystal, resulting in a decrease in display contrast. In addition, static electricity tends to accumulate in the liquid crystal cell, and charges are also accumulated in the liquid crystal cell by the application of an asymmetric voltage generated by driving, and these accumulated charges (residual DC) cause the alignment of the liquid crystal to become disturbed, or as an afterimage or burn-in. It affects the display and significantly deteriorates the display quality of the liquid crystal device. In this state, when electricity is applied again, the liquid crystal molecules are not properly controlled in the initial stage, resulting in flicker or the like. In particular, in the horizontal electric field method, since the distance between the pixel electrode and the common electrode is closer than in the longitudinal electric field method, there is a problem that a strong electric field acts on the alignment film or liquid crystal layer, and this problem is likely to become noticeable.

Japanese Patent No. 3893659 Korean Patent Application Publication No. 10-2016-0042614 Korean Patent Application Publication No. 10-2017-0127966 Korean Patent Application Publication No. 10-2018-0020722

M. Shadt et al., Jpn. J. Appl. Phys. 31, 2155 (1992). K. Ichimura et al., Chem. Rev. 100, 1847 (2000).

As described above, the photo-alignment method does not require the rubbing process itself compared to the rubbing method, which has been conventionally used industrially as an alignment treatment method for liquid crystal display elements, and therefore has a great advantage. And, compared to the rubbing method in which the orientation control ability becomes substantially constant by rubbing, in the photo-alignment method, the orientation control ability can be controlled by changing the irradiation amount of polarized light. However, in the photo-alignment method, when attempting to achieve the same degree of alignment control as in the case of the rubbing method, a large amount of irradiation of polarized light is required, or stable alignment of the liquid crystal may not be realized.

For example, in the decomposition-type photo-alignment method described in Patent Document 1 above, it is necessary to irradiate the polyimide film with ultraviolet light from a high-pressure mercury lamp with an output of 500 W for 60 minutes, which requires irradiation of large amounts of ultraviolet rays for a long period of time. need. Also, in the case of dimerization type or photoisomerization type photo-alignment method, there are cases where a large amount of ultraviolet irradiation on the order of several joules to tens of J is required. In addition, in the case of photo-crosslinking type or photo-isomerization type photo-alignment method, the thermal stability and light stability of liquid crystal orientation are poor, so there is a problem that alignment defects and display burn-in occur when used as a liquid crystal display device. In particular, in a transverse electric field driven liquid crystal display device, liquid crystal molecules are switched in-plane, so misalignment of the liquid crystal after driving the liquid crystal is likely to occur, and display burn-in due to liquid crystal misalignment is a major problem.

Therefore, in the photo-alignment method, there is a demand for improving the efficiency of the alignment treatment and realizing stable liquid crystal orientation, and a liquid crystal alignment film and a liquid crystal aligning agent that can provide high orientation control ability to the liquid crystal alignment film with high efficiency are required.

In addition, as a countermeasure against display burn-in caused by residual DC, when used as a liquid crystal alignment film, polyamic acid with a low volume resistivity is used as a component different from polyamic acid or polyimide that provides the ability to control the orientation of the liquid crystal by polarized ultraviolet irradiation. A method of adding an orientation agent has been used. However, by storing the liquid crystal aligning agent in which two types of polyamic acid or polyimide are mixed at 23 degreeC, liquid crystal orientation stability may fall with the passage of storage time. Therefore, there is a demand for a liquid crystal aligning film and a liquid crystal aligning agent that does not reduce liquid crystal orientation stability while eliminating display burn-in caused by residual DC.

The present invention provides a substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display device, which provides orientation control with high efficiency and is excellent in burn-in characteristics resulting from liquid crystal misalignment or residual DC, and a transverse electric field driven liquid crystal display having the substrate. The purpose is to provide devices.

The present inventors conducted intensive studies to solve the above problems, and as a result, a polyamic acid obtained from a specific aromatic tetracarboxylic dianhydride and a diamine or an imidized polymer of a polyamic acid, and an aliphatic tetracarboxylic dianhydride having a specific structure. It was discovered that by using a polyamic acid obtained from diamine or an imidized polymer of a polyamic acid, a liquid crystal alignment film was obtained that provided orientation control ability with high efficiency and was excellent in burn-in characteristics resulting from liquid crystal misalignment and residual DC, and completed the present invention. .

In this way, the present invention is based on the above findings and has the following gist.

1. (A-a) At least one selected from polyamic acid obtained by using a tetracarboxylic dianhydride component and a diamine component containing tetracarboxylic dianhydride represented by the following formula (1), and an imidized polymer of the polyamic acid types of polymers,

(A-b) 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 an imidized polymer of the polyamic acid. at least one type of polymer,

and an organic solvent, and the weight ratio of (A-a) and (A-b) is (A-a):(A-b) = 55:45 to 90:10, preferably 60:40 to 90:10, more preferably 60. : 40 ~ 85 : 15 Liquid crystal aligning agent.

[Formula 1]

In formula (1), i is 0 or 1, and It is a group consisting of branched alkylene, cyclic alkylene having 3 to 12 carbon atoms, sulfonyl, amide bond, or a combination thereof, wherein alkylene having 1 to 20 carbon atoms is selected from ester bond and ether bond. It may be interrupted by a bond, and the carbon atoms of phenylene and alkylene may be substituted with one or more same or different substituents selected from halogen atoms, cyano groups, alkyl groups, haloalkyl groups, alkoxy groups, and haloalkoxy groups. .

2. 10 to 100 mol% in the tetracarboxylic dianhydride component of the above (A-a) is tetracarboxylic dianhydride of formula (1), the liquid crystal aligning agent according to 1, characterized by the above-mentioned.

3. The liquid crystal aligning agent according to 1 or 2, wherein 10 to 100 mol% of the tetracarboxylic dianhydride component of the (A-b) is aliphatic tetracarboxylic dianhydride.

4. The liquid crystal aligning agent according to any one of 1 to 3, wherein 10 to 100 mol% of the diamine component of the above (A-b) is diamine of the formula (2).

5. Among 1 to 4, wherein the tetracarboxylic dianhydride represented by the formula (1) is at least one selected from pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride. The liquid crystal aligning agent described in any one.

6. The liquid crystal aligning agent according to any one of items 1 to 5, wherein the aliphatic tetracarboxylic dianhydride is cyclobutanetetracarboxylic dianhydride or 1,3-dimethylcyclobutanetetracarboxylic dianhydride.

7. [I] A step of forming a coating film by applying the composition according to any one of 1 to 6 above onto a substrate having a conductive film for driving a transverse electric field;

[II] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I]; and

[III] Process of heating the coating film obtained in [II]

A method for producing a substrate having the liquid crystal alignment film, which obtains a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which orientation control ability is imparted.

8. A substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element manufactured by the method described in 7 above.

9. A transverse electric field driven liquid crystal display device having the substrate described in item 8 above.

10. Step of preparing the substrate (first substrate) described in 8 above;

[I'] A step of forming a coating film by applying the composition according to claims 1 to 6 on a second substrate;

[II'] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I'];

[III'] Process of heating the coating film obtained in [II']; A process of obtaining a second substrate having the liquid crystal aligning film, which obtains a liquid crystal aligning film to which orientation control ability is imparted by having; and

[IV] A process of obtaining a liquid crystal display element by arranging the first and second substrates to face each other so that the liquid crystal alignment films of the first and second substrates face each other with liquid crystal interposed therebetween; A method of manufacturing a liquid crystal display device, wherein a transverse electric field driven liquid crystal display device is obtained.

11. A transverse electric field driven liquid crystal display device manufactured by the method described in 10 above.

The liquid crystal aligning film obtained from the liquid crystal aligning agent of this invention can orientate a liquid crystal with a small amount of polarization|polarized-light ultraviolet irradiation, and even if a liquid crystal aligning agent is stored at 23 degreeC, it does not worsen the liquid crystal orientation stability of a liquid crystal aligning film by direct current voltage. It is possible to quickly alleviate accumulated residual DC.

The liquid crystal aligning agent of this invention is (A-a) a polyamic acid obtained using a tetracarboxylic dianhydride component containing tetracarboxylic dianhydride represented by the following formula (1), and a diamine component, and imidation of the polyamic acid. A polyamic acid obtained by using at least one type of polymer selected from polymers, (A-b) a tetracarboxylic dianhydride component containing an aliphatic tetracarboxylic dianhydride, and a diamine component containing a diamine represented by the following formula (2) and at least one type of polymer selected from imidized polymers of the polyamic acid, and an organic solvent, and the weight ratio of (A-a) and (A-b) is (A-a):(A-b) = 55:45 to 90:10. It is preferably 60:40 to 90:10, more preferably 60:40 to 85:15.

[Formula 2]

In formula (1), i is 0 or 1, and It is a group consisting of branched alkylene, cyclic alkylene having 3 to 12 carbon atoms, sulfonyl, amide bond, or a combination thereof, wherein alkylene having 1 to 20 carbon atoms is selected from ester bond and ether bond. It may be interrupted by a bond, and the carbon atoms of phenylene and alkylene may be substituted with one or more same or different substituents selected from halogen atoms, cyano groups, alkyl groups, haloalkyl groups, alkoxy groups, and haloalkoxy groups. .

Below, each configuration requirement is described in detail.

<(A-a) component>

The (A-a) component used in the liquid crystal aligning agent of this invention is a polyamic acid obtained using a tetracarboxylic dianhydride component containing tetracarboxylic dianhydride represented by the said formula (1), and a diamine component, and its polya It is at least one type of polymer selected from imidized polymers of mixed acids.

<Tetracarboxylic dianhydride component>

Examples of the tetracarboxylic dianhydride represented by the formula (1) include the following compounds, but are not limited to these. In addition, in the following formula, q represents an integer of 1 to 20.

[Formula 3]

Among tetracarboxylic dianhydrides represented by formula (1), the above formulas (1-1), (1-2), (1-3), (1-) are used in terms of relaxation of residual DC accumulated by direct current voltage. 4), (1-5), and (1-7) are preferable, and from the viewpoint of stable supply, the above formulas (1-1) and (1-5) are particularly preferable.

In the component (A-a), if the amount of tetracarboxylic dianhydride represented by formula (1) in the entire tetracarboxylic dianhydride component is too small, the effect of the present invention will not be obtained. Therefore, the amount of tetracarboxylic dianhydride represented by formula (1) is preferably 30 to 100 mol%, more preferably 30 to 100 mol%, based on 1 mole of all tetracarboxylic dianhydrides used in the production of component (A-a). is 50 to 100 mol%, more preferably 70 to 100 mol%.

The tetracarboxylic dianhydride represented by formula (1) may be used individually, or may be used in combination, but in that case as well, the tetracarboxylic dianhydride represented by formula (1) is the above in total. It is desirable to use the desired amount.

<Diamine ingredient>

As a diamine component used for manufacture of the (A-a) component of this invention, the diamine represented by the following formula (5) is used.

[Formula 4]

W ² in formula (5) is a divalent organic group, and its structure is not particularly limited, and two or more types may be mixed. If a specific example is to be shown, the structure represented by the following formula [W ² -1] to [W ² -152] can be given. R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom or a methyl group is more preferable.

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

Among them, from the viewpoint of alleviating residual DC accumulated by direct current voltage, W2-7, W2-8, W2-20, W2-21, W2-23, W2-24, W2-26, W2-40, 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 is preferable, and W2-65, W2-67, W2-68, W2-69, W2-70, W2-71, W2-142, W2-144, W2-148, and W2-151 are more preferable.

<(A-b) component>

The (A-b) component used in the liquid crystal aligning agent of this invention is obtained using the tetracarboxylic dianhydride component containing aliphatic tetracarboxylic dianhydride, and the diamine component containing the diamine represented by said formula (2). It is at least one type of polymer selected from polyamic acids and imidated polymers of polyamic acids.

Examples of the specific aliphatic tetracarboxylic dianhydride used in the present invention include tetracarboxylic dianhydride represented by the following formula (3). In addition, in the formula, X ₁ is any of the following (X-1) to (X-28).

[Formula 23]

[Formula 24]

[Formula 25]

[Formula 26]

In 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 a hydrogen atom or a methyl group is more preferable.

Among the above, (X-1) is most preferable in terms of photo-alignment, and in (X-1), R ₃ and R ₅ are methyl groups, R ₄ and R ₆ are hydrogen atoms, and R ₃ to R ₆ are A structure in which R 3 to R 6 is a hydrogen atom is preferable, and among these, a structure in which R ₃ to R ₆ is a hydrogen atom is particularly preferable.

In component (A-b), if the amount of aliphatic acid dianhydride in the entire tetracarboxylic dianhydride component is too small, the effect of the present invention will not be obtained. Therefore, the amount of aliphatic tetracarboxylic dianhydride is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, based on 1 mole of all tetracarboxylic dianhydrides used in producing component (A-b). mol%, more preferably 80 to 100 mol%.

The ratio of the diamine represented by formula (2) in the polyamic acid and the imidized polymer of the polyamic acid, which are the component (A-b) of the present invention, is 10 to 100 with respect to 1 mole of the total diamine used in the production of the component (A-b). It is preferably mol%, more preferably 30 to 100 mol%, and even more preferably 50 to 100 mol%.

The imidized polymer of the polyamic acid and polyamic acid which are the (A-b) components contained in the liquid crystal aligning agent of this invention may use the diamine represented by the said formula (5) other than the diamine represented by the said formula (2).

In the polyamic acid which is the (A-b) component contained in the liquid crystal aligning agent of this invention, and the imidized polymer of polyamic acid, if the ratio of the diamine represented by Formula (5) increases, the effect of this invention may be impaired. , is not desirable. Therefore, the ratio of diamine represented by Formula (5) is preferably 0 to 90 mol%, more preferably 0 to 70 mol%, and even more preferably 0 to 50 mol% with respect to 1 mole of all diamines.

<Method for producing polyamic acid>

Polyamic acid, which is a polyimide precursor used in the present invention, can be synthesized by the method shown below.

Specifically, it is synthesized by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent at -20 to 150°C, preferably 0 to 70°C, for 30 minutes to 24 hours, preferably 1 to 12 hours. can do.

The organic solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. from the solubility of monomers and polymers, and one or two types of these are used. You may use a mixture of the above.

The concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer does not occur easily and a high molecular weight body is easily obtained.

The polyamic acid obtained as described above can be recovered by injecting the reaction solution into a poor solvent while stirring well to precipitate the polymer. Additionally, purified polyamic acid powder can be obtained by performing precipitation several times, washing with a poor solvent, and drying at room temperature or by heating. The poor solvent is not particularly limited, but includes water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, etc., and water, methanol, ethanol, 2-propanol, etc. are preferred.

<Method for producing polyimide>

The polyimide used in the present invention can be manufactured by imidizing the polyamic acid.

When producing polyimide from polyamic acid, chemical imidization is simple by adding a catalyst to a solution of the polyamic acid obtained from the reaction of a diamine component and tetracarboxylic dianhydride. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization process.

Chemical imidization can be performed by stirring the polymer to be imidized in the presence of a basic catalyst and an acid anhydride in an organic solvent. As the organic solvent, the solvent used during the polymerization reaction described above can be used. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has an appropriate basicity to proceed with the reaction. Additionally, acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among these, acetic anhydride is preferred because it facilitates purification after completion of the reaction.

The temperature when performing the imidization reaction is -20 to 140°C, preferably 0 to 100°C, and the reaction time can be from 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times the mole of the polyamic acid group, preferably 2 to 20 times the mole, and the amount of the acid anhydride is 1 to 50 times the mole of the polyamic acid group, preferably 3 to 30 times the mole. The imidization rate of the obtained polymer can be controlled by adjusting the catalyst amount, temperature, and reaction time.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid, the obtained imidized polymer is recovered by the means described below, re-dissolved in an organic solvent, and used as the liquid crystal aligning agent of the present invention. desirable.

The solution of polyimide obtained as described above can be injected into a poor solvent while stirring well to precipitate the polymer. Precipitation can be performed several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polymer powder.

The poor solvent is not particularly limited, but includes methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene. , 2-propanol, acetone, etc. are preferred.

The weight ratio of component (A-a) and component (A-b) prepared in this way is (A-a):(A-b) = 55:45 to 90:10, preferably 60:40 to 90:10, more preferably 60. : 40 ~ 85 : 15, the effect of the invention is exhibited. That is, within the above range, the relaxation of residual DC accumulated by direct current is rapid and the liquid crystal orientation stability is excellent, so the burn-in characteristic is excellent.

The polyimide precursor used in the present invention is obtained from the reaction of a diamine component and a tetracarboxylic acid derivative, and includes polyamic acid and polyamic acid ester.

<Manufacture of polyimide precursor-polyamic acid>

Follow the description of the polyamic acid production method described in the sections for component (A-a) and component (A-b).

<Manufacture of polyimide precursor-polyamic acid ester>

Polyamic acid ester, which is a polyimide precursor used in the present invention, can be manufactured by the production method (1), (2), or (3) shown below.

(1) When manufactured from polyamic acid

Polyamic acid ester can be produced by esterifying the polyamic acid prepared as above. Specifically, it can be prepared by reacting polyamic acid and an esterifying agent in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 4 hours. You can.

The esterifying agent is preferably one that can be easily removed by purification, and includes N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentylbutyl acetal, N,N-dimethylformamide di-t-butyl acetal, 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-methylmorpholinium chloride, etc. The amount of the esterifying agent added is preferably 2 to 6 molar equivalents per 1 mole of repeating units of the polyamic acid.

Organic solvents include, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide. , dimethyl sulfoxide, or 1,3-dimethyl-imidazolidinone. In addition, when the solvent solubility of the polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or formula [D-1] to formula described later The solvent represented by [D-3] can be used.

These solvents may be used individually or may be used in combination. Furthermore, even if it is a solvent that does not dissolve the polyimide precursor, it may be used by mixing with the solvent as long as the produced polyimide precursor does not precipitate. In addition, since moisture in the solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyimide precursor, it is preferable to use a dehydrated and dried solvent.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone due to the solubility of the polymer, and these are used singly or in a mixture of two or more. You can use it. The concentration during production is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, because precipitation of the polymer does not occur easily and it is easy to obtain a high molecular weight body.

(2) When manufactured by reaction of tetracarboxylic acid diester dichloride and diamine

Polyamic acid ester can be manufactured from tetracarboxylic acid diester dichloride and diamine.

Specifically, tetracarboxylic acid diester dichloride and diamine are reacted in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 20°C. It can be prepared by reacting for 4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used as the base, but pyridine is preferred so that the reaction proceeds gently. The amount of base added is preferably 2 to 4 times the mole of the tetracarboxylic acid diester dichloride because it is an amount that is easy to remove and makes it easy to obtain a high molecular weight product.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of monomers and polymers, and these may be used one type or in a mixture of two or more types. The polymer concentration during production is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, because precipitation of the polymer does not occur easily and it is easy to obtain a high molecular weight body. Moreover, in order to prevent hydrolysis of tetracarboxylic acid diester dichloride, the solvent used in the production of polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of external air in a nitrogen atmosphere.

(3) When manufactured from tetracarboxylic acid diester and diamine

Polyamic acid ester can be manufactured by polycondensing tetracarboxylic acid diester and diamine.

Specifically, tetracarboxylic acid diester and diamine are reacted in the presence of a condensing agent, a base, and an organic solvent at 0°C to 150°C, preferably 0°C to 100°C, for 30 minutes to 24 hours, preferably 3. It can be prepared by reacting for ~15 hours.

The condensing agent includes triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, and dimethoxy-1. ,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazole- 1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphite, (2,3-dihydro-2-thioxo-3-benzooxazolyl)phosphonate diphenyl, etc. You can use it. The amount of condensing agent added 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 base added is preferably 2 to 4 times the mole of the diamine component because it is an amount that is easy to remove and makes it easy to obtain a high molecular weight body.

Additionally, in the above reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The amount of Lewis acid added is preferably 0 to 1.0 times the mole of the diamine component.

Among the three methods for producing polyamic acid ester, the production method (1) or (2) above is particularly preferable because a high molecular weight polyamic acid ester is obtained.

The solution of polyamic acid ester obtained as described above can be injected into a poor solvent while stirring well to precipitate the polymer. Precipitation can be performed several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polyamic acid ester powder. The poor solvent is not particularly limited, but examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Liquid crystal alignment agent>

The liquid crystal aligning agent used in the present invention has the form of a solution in which a polymer component is dissolved in an organic solvent. The weight average molecular weight of the polymer is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000. Moreover, 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 aligning agent used in the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, but is preferably 1% by mass or more in terms of forming a uniform and defect-free coating film, and the solution In terms of storage stability, it is preferable to set it to 10% by mass or less. A particularly preferable polymer concentration is 2 to 8 mass%.

The organic solvent contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as the polymer component is dissolved uniformly. Specific examples include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. Don, N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3- Methoxy-N,N-dimethylpropanamide, etc. can be mentioned. These may be used singly or in mixture of two or more types. Additionally, it may be a solvent that cannot uniformly dissolve the polymer component alone, or may be mixed with the above-mentioned organic solvent as long as it is in a range where the polymer does not precipitate.

In addition, the organic solvent contained in the liquid crystal aligning agent generally uses a mixed solvent in which a solvent that improves the coating properties when applying the liquid crystal aligning agent or the surface smoothness of the coating film in addition to the above-described solvents is used. Also in the liquid crystal aligning agent of the invention, such a mixed solvent is preferably used. Specific examples of organic solvents used in combination are given below, but are not limited to these examples.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, Isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1- Butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methyl Cyclohexanol, 3-methylcyclohexanol, 2,6-dimethyl-4-heptanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1 ,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diisopropyl ether , dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol Diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone Tanone, 4-heptanone, 2,6-dimethyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutylacetate, 1-methylpentylacetate, 2-ethylbutylacetate, 2- Ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2 -(hexyloxy)ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(butoxyethoxy)propanol, propylene Glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate. , Ethylene glycol 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, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, 3-Methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3- Butyl methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, solvents represented by the following formulas [D-1] to [D-3], etc. You can.

[Formula 27]

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 them, preferred solvent combinations include N-methyl-2-pyrrolidone, γ-butyrolactone, ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol mono. Butyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene. Glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone, propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanone, N-methyl-2-pyrrolidone and γ- Butyrolactone, propylene glycol monobutyl ether, diisopropyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, 2,6-dimethyl-4-heptanol, N- Examples include methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether. The type and content of such a solvent are appropriately selected depending on the coating device, application conditions, application environment, etc. of the liquid crystal aligning agent.

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

[Formula 28]

[Formula 29]

It is preferable that these additives are 0.1-30 mass parts with respect to 100 mass parts of the polymer component contained in a liquid crystal aligning agent. If it is less than 0.1 parts by mass, no effect can be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal is lowered, so the amount is more preferably 0.5 to 20 parts by mass.

In addition to the above, the liquid crystal aligning agent of the present invention includes a polymer other than the polymer, a dielectric or conductive material for the purpose of changing electrical properties such as dielectric constant and conductivity of the liquid crystal aligning film, and a liquid crystal aligning film, as long as it is a range in which the effect of the present invention is not impaired. A silane coupling agent for the purpose of improving adhesion to the substrate, a crosslinkable compound for the purpose of increasing the hardness and density of the film when used as a liquid crystal alignment film, and further for the purpose of efficiently advancing the imidization of the polyamic acid when baking the coating film. An imidization accelerator or the like may be added.

<Liquid crystal alignment film> and <Method for producing liquid crystal alignment film>

The liquid crystal aligning film of this invention is a film|membrane obtained by apply|coating the said liquid crystal aligning agent to a board|substrate, drying, and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, and polycarbonate substrates can be used, and ITO electrodes for driving liquid crystals. It is preferable to use a substrate on which a back is formed in terms of simplification of the process. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one side of the substrate is used, and a light-reflecting material such as aluminum can also be used as the electrode in this case.

Examples of the application method of the liquid crystal aligning agent of the present invention include spin coating, printing, and inkjet methods. The drying and baking steps after applying the liquid crystal aligning agent of the present invention can be performed at any temperature and time. Usually, in order to sufficiently remove the organic solvent contained, it is dried at 50°C to 120°C for 1 to 10 minutes, and then baked at 150°C to 300°C for 5 to 120 minutes. The thickness of the coating film after baking is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may decrease, so it is 5 to 300 nm, preferably 10 to 200 nm.

Methods for orientation processing the obtained liquid crystal aligning film include a rubbing method and a photo-alignment treatment method.

Rubbing treatment can be performed using an existing rubbing device. Materials of the rubbing fabric at this time include cotton, nylon, rayon, etc. Conditions for the rubbing treatment generally include a rotation speed of 300 to 2000 rpm, a feed rate of 5 to 100 mm/s, and an indentation amount of 0.1 to 1.0 mm. Afterwards, residues created by rubbing are removed by ultrasonic cleaning using pure water or alcohol.

As a specific example of the photo-alignment treatment method, a method of imparting liquid crystal alignment ability by irradiating radiation deflected in a certain direction to the surface of the coating film and, in some cases, further performing heat treatment at a temperature of 150 to 250°C. can be mentioned. As radiation, ultraviolet rays and visible rays having a wavelength of 100 nm to 800 nm can be used. Among these, ultraviolet rays with a wavelength of 100 nm to 400 nm are preferable, and those with a wavelength of 200 nm to 400 nm are particularly preferable. Moreover, in order to improve the liquid crystal orientation, radiation may be irradiated while heating the coated film substrate at 50 to 250°C. The radiation dose is preferably 1 to 10,000 mJ/cm2, and particularly preferably 100 to 5,000 mJ/cm2. The liquid crystal alignment film manufactured as described above can stably orientate liquid crystal molecules in a certain direction.

The higher the extinction ratio of polarized ultraviolet rays, the higher the anisotropy can be imparted, so it is preferable. Specifically, the extinction ratio of linearly polarized ultraviolet rays is preferably 10:1 or more, and more preferably 20:1 or more.

In the above, the film irradiated with polarized radiation may be subsequently contacted with a solvent containing at least one selected from water and an organic solvent.

The solvent used in the contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition 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, butyl cellosolve, ethyl lactate, and 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.

In terms of versatility and safety, at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol, and ethyl lactate is more preferable. Water, 2-propanol, and mixed solvents of water and 2-propanol are particularly preferred.

In the present invention, the contact treatment between the film irradiated with polarized radiation and a solution containing an organic solvent is preferably carried out by a treatment in which the film and the liquid are in sufficient contact, such as immersion treatment or spray treatment. Among these, a method of immersing the film in a solution containing an organic solvent is preferred, preferably for 10 seconds to 1 hour, and more preferably for 1 to 30 minutes. The contact treatment may be heated at room temperature, but is preferably carried out at 10 to 80°C, more preferably 20 to 50°C. Additionally, means to increase contact, such as ultrasonic waves, can be implemented as needed.

After the contact treatment, for the purpose of removing the organic solvent in the used solution, either rinsing or drying with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or both. Just implement it.

Additionally, the membrane subjected to the contact treatment with a solvent above may be heated at 150°C or higher for the purpose of drying the solvent and reorienting the molecular chains in the membrane.

The heating temperature is preferably 150 to 300°C. The higher the temperature, the more the reorientation of the molecular chain is promoted, but if the temperature is too high, there is a risk of decomposition of the molecular chain. Therefore, as a heating temperature, 180 to 250°C is more preferable, and 200 to 230°C is particularly preferable.

If the heating time is too short, the effect of reorienting the molecular chain may not be obtained, and if it is too long, the molecular chain may be decomposed. Therefore, the heating time is preferably 10 seconds to 30 minutes, and more preferably 1 minute to 10 minutes. do.

As a manufacturing method of the board|substrate with a liquid crystal alignment film of this invention, it is preferable to include the processes of following [I] - [IV].

[I] (A-a) At least one selected from polyamic acids obtained by using a tetracarboxylic dianhydride component and a diamine component containing tetracarboxylic dianhydride represented by formula (1), and imidized polymers of the polyamic acids. Polyamic acid obtained by using a type of polymer, (A-b) a tetracarboxylic dianhydride component containing aliphatic tetracarboxylic dianhydride and a diamine component containing the diamine represented by formula (2), and imidization of the polyamic acid A process of applying a liquid crystal aligning agent containing at least one type of polymer selected from polymers and an organic solvent onto a substrate having a conductive film for transverse electric field drives to form a coating film;

[II] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I]; and

[III] Process of heating the coating film obtained in [II];

has

Through the above process, a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which orientation control ability is imparted can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

Also, by preparing a second substrate in addition to the obtained substrate (first substrate), a transverse electric field driven liquid crystal display device can be obtained.

The second substrate is made by using the above-mentioned steps [I] to [III] (a conductive film for driving a horizontal electric field) except that a substrate without a conductive film for driving a horizontal electric field is used instead of a substrate having a conductive film for driving a horizontal electric field. Since a substrate that does not have a substrate is used, for convenience, in this application, it may be abbreviated as steps [I'] to [III']), thereby obtaining a second substrate having a liquid crystal alignment film to which orientation control ability is imparted. there is.

The method of manufacturing a transverse electric field driven liquid crystal display device is:

[IV] A process of obtaining a liquid crystal display element by arranging the first and second substrates obtained above so that the liquid crystal alignment films of the first and second substrates face each other with liquid crystal interposed therebetween;

has As a result, a transverse electric field driven liquid crystal display device can be obtained.

Hereinafter, each process [I] to [III] and [IV] of the production method of the present invention will be described.

<Process [I]>

In step [I], a polymer composition containing a photosensitive template polymer and an organic solvent is applied onto a substrate having a conductive film for driving a transverse electric field to form a coating film.

<Substrate>

The substrate is not particularly limited, but when the liquid crystal display element to be manufactured is a transmissive type, it is preferable that a highly transparent substrate is used. In that case, there is no particular limitation, and a glass substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, etc. can be used.

Additionally, considering application to reflective liquid crystal display elements, opaque substrates such as silicon wafers can also be used.

<Conductive film for driving transverse electric field>

The substrate has a conductive film for driving a transverse electric field.

As the conductive film, when the liquid crystal display element is a transmissive type, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), etc. may be used, but it is not limited to these.

In addition, in the case of a reflective liquid crystal display element, the conductive film may include, but is not limited to, a material that reflects light, such as aluminum.

A conventionally known method can be used to form a conductive film on a substrate.

The method of applying the above-described polymer composition onto a substrate having a conductive film for driving a transverse electric field is not particularly limited.

Industrially, the application method is generally performed by screen printing, offset printing, flexo printing, or inkjet method. Other application methods include the dip method, roll coater method, slit coater method, spinner method (rotation application method), or spray method, and these may be used depending on the purpose.

After applying the polymer composition on a substrate having a conductive film for driving a transverse electric field, the temperature is heated to 50 to 300° C., preferably 50 to 180° C., using a heating means such as a hot plate, a thermal circulation oven, or an IR (infrared) type oven. A coating film can be obtained by evaporating the solvent at ℃. The drying temperature at this time is preferably lower than that of the [III] process from the viewpoint of liquid crystal orientation stability.

If the thickness of the coating film is too thick, it becomes disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, it is preferably 5 nm to 300 nm, more preferably 10 nm to 10 nm. It is 150 nm.

In addition, it is also possible to form a process in which the substrate on which the coating film is formed is cooled to room temperature after the [I] process and before the subsequent [II] process.

<Process [II]>

In step [II], polarized ultraviolet rays are irradiated to the coating film obtained in step [I]. When irradiating polarized ultraviolet rays to the film surface of the coating film, the polarized ultraviolet rays are irradiated through a polarizing plate in a certain direction with respect to the substrate. As ultraviolet rays to be used, ultraviolet rays with a wavelength in the range of 100 nm to 400 nm can be used. Preferably, the optimal wavelength is selected through a filter or the like depending on the type of coating film used. And, for example, ultraviolet rays with a wavelength in the range of 240 nm to 400 nm can be selected and used so as to selectively cause a photodecomposition reaction. As ultraviolet rays, for example, light emitted from a high-pressure mercury lamp or a metal halide lamp can be used.

The irradiation amount of polarized ultraviolet rays depends on the coating film used. The irradiation amount is the amount of polarized ultraviolet rays that realizes the maximum value of ΔA (hereinafter also referred to as ΔAmax), which is the difference between the ultraviolet ray absorbance in the direction parallel to the polarization direction of the polarized ultraviolet ray and the ultraviolet ray absorbance in the direction perpendicular to the coating film. It is preferable to set it within the range of 1% to 70%, and it is more preferable to set it within the range of 1% to 50%.

<Process [III]>

In step [III], the coating film irradiated with polarized ultraviolet rays in step [II] is heated. By heating, orientation control ability can be imparted to the coating film.

Heating can be performed using a heating means such as a hot plate, a thermal circulation oven, or an IR (infrared) oven. The heating temperature can be determined in consideration of the temperature at which the coating film to be used develops good liquid crystal orientation stability and electrical properties.

The heating temperature is preferably within the temperature range at which the main chain polymer exhibits good liquid crystal orientation stability. When the heating temperature is too low, the amplification effect of thermal anisotropy and thermal imidization tend to become insufficient, and when the heating temperature is too high above the temperature range, the anisotropy imparted by polarization exposure tends to disappear, In some cases, self-organization may make it difficult to reorient in one direction.

The thickness of the coating film formed after heating is preferably 5 nm to 300 nm, more preferably 50 nm to 150 nm, for the same reason described in step [I].

By having the above steps, the production method of the present invention can realize the introduction of anisotropy into the coating film with high efficiency. And a substrate with a liquid crystal alignment film can be manufactured with high efficiency.

<Process [IV]>

Step [IV] is a substrate (first substrate) having a liquid crystal alignment film on a conductive film for transverse electric field driving obtained in step [III], and similarly obtained in steps [I'] to [III'] above, A substrate with a liquid crystal alignment film (second substrate) without a conductive film is arranged to face each other with liquid crystal interposed so that both liquid crystal alignment films are opposed to each other, and a liquid crystal cell is manufactured by a known method to manufacture a transverse electric field driven liquid crystal display element. It is a process.

In addition, the steps [I'] to [III'] are the steps [ It can be carried out in the same way as I] to [III]. Since the only difference between steps [I] to [III] and steps [I'] to [III'] is the presence or absence of the conductive film described above, the description of steps [I'] to [III'] is omitted.

<Liquid crystal display device>

The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal aligning film from the liquid crystal aligning agent of the present invention by the above-described liquid crystal aligning film manufacturing method, manufacturing a liquid crystal cell by a known method, and using the liquid crystal display element. It was done.

As an example of a liquid crystal cell manufacturing method, a liquid crystal display device with a passive matrix structure will be described as an example. Additionally, a liquid crystal display device may have an active matrix structure in which a switching device such as a TFT (Thin Film Transistor) is formed in each pixel portion that constitutes an image display.

First, a transparent glass substrate is prepared, a common electrode is formed on one substrate, and a segment electrode is formed on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned to enable desired image display. Next, an insulating film is formed on each substrate to cover the common electrode and the segment electrode. The insulating film can be, for example, a film made of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, on each substrate, the liquid crystal alignment film of the present invention is formed by the above-described method.

One substrate is overlapped with the other substrate so that the alignment film surfaces face each other, and the periphery is adhered with a sealant. A spacer is usually incorporated into the seal material to control the gap between the substrates. In addition, it is desirable to distribute spacers for controlling the substrate gap even in the in-plane portion where the seal material is not formed. An opening through which liquid crystal can be filled from the outside is formed in a part of the seal material.

Next, the liquid crystal material is injected into the space surrounded by the two substrates and the sealing material through the opening formed in the sealing material. Afterwards, this opening is sealed with adhesive. For injection, a vacuum injection method may be used, or a method using capillary action in the air may be used. Next, the polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surface of the two substrates opposite to the liquid crystal layer. By going through the above steps, the liquid crystal display element of the present invention is obtained.

In the present invention, a resin that is cured by ultraviolet irradiation or heating and has a reactive group such as an epoxy group, acryloyl group, methacryloyl group, hydroxyl group, allyl group, or acetyl group is used as the sealant. . In particular, it is preferable to use a cured resin system having both an epoxy group and a (meth)acryloyl group.

An inorganic filler may be added to the sealing agent of the present invention for the purpose of improving adhesiveness and moisture resistance. The inorganic filler that can be used is not particularly limited, but specifically includes 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, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., Preferred are spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, and aluminum silicate. The above inorganic fillers may be used in mixture of two or more types.

As described above, the substrate for a transverse electric field driven liquid crystal display element manufactured using the polymer of the present invention or the transverse electric field driven liquid crystal display element having the substrate has excellent liquid crystal orientation stability and residual DC with a small amount of polarized ultraviolet irradiation. Since it exhibits relaxation characteristics, it can be suitably used in large-screen, high-definition liquid crystal televisions, etc. In addition, the liquid crystal alignment film manufactured by the method of the present invention has excellent reliability and can also be used in a variable phase machine using liquid crystal, and this variable phase machine can be suitably used for, for example, an antenna that can vary the resonance frequency. You can.

Example

Below, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to these Examples. In addition, the abbreviations for compounds and solvents are as follows.

NMP: N-methyl-2-pyrrolidone

BCS: Butylcellosolve

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)

[Formula 30]

[Formula 31]

<Measurement of viscosity>

In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample volume of 1.1 ml, a cone rotor TE-1 (1°34', R24), and a temperature of 25°C. did.

<Synthesis Example 1>

Weigh 2.18 g (5.40 mmol) of DA-1 and 3.43 g (12.6 mmol) of DA-2 in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and add 55.8 g of NMP. , and was dispersed by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 3.25 g (16.6 mmol) of CA-1 was added, 23.9 g of NMP was further added, and the solution was stirred at 23°C under nitrogen atmosphere for 5 hours to form a solution of polyamic acid-polyimide copolymer. got it The viscosity of the solution of this polyamic acid-polyimide copolymer at a temperature of 25°C was 178 mPa·s.

30.2 g of the solution of this polyamic acid-polyimide copolymer was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 16.8 g of NMP and 20.1 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and the liquid crystal aligning agent was added. (A-1) was obtained.

<Synthesis Example 2>

Weigh 5.10 g (12.6 mmol) of DA-1 and 1.32 g (5.40 mmol) of DA-3 in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and add 61.8 g of NMP. , and was dispersed by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 2.19 g (11.2 mmol) of CA-1 and 1.21 g (5.40 mmol) of CA-2 were added, and 26.5 g of NMP was further added at 40°C under a nitrogen atmosphere. The mixture was stirred for 6 hours to obtain a solution of polyamic acid-polyimide copolymer. The viscosity of the solution of this polyamic acid-polyimide copolymer at a temperature of 25°C was 193 mPa·s.

31.3 g of the solution of this polyamic acid-polyimide copolymer was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 17.4 g of NMP and 20.9 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and the liquid crystal aligning agent was added. (A-2) was obtained.

<Synthesis Example 3>

Weigh 2.79 g (14.0 mmol) of DA-4 and 1.47 g (6.00 mmol) of DA-3 in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and add 50.5 g of NMP. , and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 5.59 g (19.0 mmol) of CA-3 was added, 21.7 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 20 hours, and obtained the solution of the polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25°C was 480 mPa·s.

29.0 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 25.1 g of NMP and 23.2 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (A-3) got it

<Synthesis Example 4>

Weigh 3.19 g (16.0 mmol) of DA-4 and 0.433 g (4.00 mmol) of DA-5 in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and add 47.3 g of NMP. , and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 5.59 g (19.0 mmol) of CA-3 was added, 20.3 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 20 hours, and obtained the solution of the polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25°C was 455 mPa·s.

30.7 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 26.6 g of NMP and 24.6 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (A-4) got it

<Synthesis Example 5>

3.19 g (16.0 mmol) of DA-4 and 0.433 g (4.00 mmol) of DA-6 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 47.3 g of NMP was added. , and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 5.59 g (19.0 mmol) of CA-3 was added, 20.3 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 20 hours, and obtained the solution of the polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25°C was 418 mPa·s.

30.1 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 26.1 g of NMP and 24.1 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (A-5) was added. got it

<Synthesis Example 6>

3.19 g (16.0 mmol) of DA-4 and 0.977 g (4.00 mmol) of DA-3 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 41.0 g of NMP was added. , and dissolved by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 1.65 g (8.40 mmol) of CA-1 was added, and after stirring at 23°C in a nitrogen atmosphere for 4 hours, 2.18 g (10.0 mmol) of CA-4 was added, and further 17.6 g of NMP was added and stirred at 50°C for 18 hours in a nitrogen atmosphere to obtain a polyamic acid solution. The viscosity of this polyamic acid solution at a temperature of 25°C was 246 mPa·s.

29.7 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 25.7 g of NMP and 23.8 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (A-6) was added. got it

<Synthesis Example 7>

3.97 g (20.0 mmol) of DA-7 was weighed and taken in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, 49.1 g of NMP was added, and the mixture was stirred and dissolved while sending nitrogen. While stirring this diamine solution under water cooling, 5.59 g (19.0 mmol) of CA-3 was added, 21.0 g of NMP was further added, and it stirred at 50 degreeC under nitrogen atmosphere for 20 hours, and obtained the solution of the polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25°C was 376 mPa·s.

30.4 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 26.4 g of NMP and 24.3 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (A-7) was added. got it

<Synthesis Example 8>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 8.07 g of the liquid crystal aligning agent (A-1) obtained in Synthesis Example 1 and 12.1 g of the liquid crystal aligning agent (A-3) obtained in Synthesis Example 3 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-8).

<Synthesis Example 9>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 8.12 g of the liquid crystal aligning agent (A-1) obtained in Synthesis Example 1 and 12.2 g of the liquid crystal aligning agent (A-4) obtained in Synthesis Example 4 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-9).

<Synthesis Example 10>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 8.21 g of the liquid crystal aligning agent (A-1) obtained in Synthesis Example 1 and 12.3 g of the liquid crystal aligning agent (A-5) obtained in Synthesis Example 5 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-10).

<Synthesis Example 11>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 6.02 g of the liquid crystal aligning agent (A-2) obtained in Synthesis Example 2 and 14.0 g of the liquid crystal aligning agent (A-6) obtained in Synthesis Example 6 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-11).

<Synthesis Example 12>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 6.11 g of the liquid crystal aligning agent (A-2) obtained in Synthesis Example 2 and 14.3 g of the liquid crystal aligning agent (A-7) obtained in Synthesis Example 7 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-12).

<Synthesis Example 13>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 4.24 g of the liquid crystal aligning agent (A-1) obtained in Synthesis Example 1 and 16.96 g of the liquid crystal aligning agent (A-3) obtained in Synthesis Example 3 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (A-13).

<Comparative Synthesis Example 1>

2.18 g (5.40 mmol) of DA-1 and 3.43 g (12.6 mmol) of DA-2 were weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 58.1 g of NMP was added. , and was dispersed by stirring while sending nitrogen. While stirring this diamine solution under water cooling, 3.61 g (16.6 mmol) of CA-4 was added, 24.9 g of NMP was further added, and the mixture was stirred at 50°C in a nitrogen atmosphere for 18 hours to form a polyamic acid-polyimide copolymer. A solution was obtained. The viscosity of the solution of this polyamic acid-polyimide copolymer at a temperature of 25°C was 269 mPa·s.

30.6 g of the solution of this polyamic acid-polyimide copolymer was aliquoted into a 100 ml Erlenmeyer flask containing a stirrer, 17.0 g of NMP and 20.4 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and the liquid crystal aligning agent was added. (B-1) was obtained.

<Comparative Synthesis Example 2>

3.97 g (20.0 mmol) of DA-7 was weighed and taken in a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, 39.5 g of NMP was added, and the mixture was stirred and dissolved while sending nitrogen. While stirring this diamine solution under water cooling, 3.73 g (19.0 mmol) of CA-1 was added, 16.9 g of NMP was further added, and it stirred at 23 degreeC under nitrogen atmosphere for 4 hours, and obtained the solution of the polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25°C was 265 mPa·s.

29.9 g of this polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 25.9 g of NMP and 23.9 g of BCS were added, stirred for 2 hours with a magnetic stirrer, and liquid crystal aligning agent (B-2) was added. got it

<Comparative Synthesis Example 3>

In a 50 mL Erlenmeyer flask containing a stirrer, 8.14 g of the liquid crystal aligning agent (B-1) obtained in Comparative Synthesis Example 1 and 12.2 g of the liquid crystal aligning agent (A-3) obtained in Synthesis Example 3 were weighed and taken, and a magnetic stirrer was added. It stirred for 2 hours and obtained the liquid crystal aligning agent (B-3).

<Comparative Synthesis Example 4>

In a 50 mL Erlenmeyer flask containing a stirrer, 6.07 g of the liquid crystal aligning agent (A-2) obtained in Synthesis Example 2 and 14.2 g of the liquid crystal aligning agent (B-2) obtained in Comparative Synthesis Example 2 were weighed, taken, and stirred with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (B-4).

<Comparative Synthesis Example 5>

In a 50 mL Erlenmeyer flask equipped with a stirrer, 10.1 g of the liquid crystal aligning agent (A-2) obtained in Synthesis Example 2 and 10.1 g of the liquid crystal aligning agent (A-7) obtained in Synthesis Example 7 were weighed and taken with a magnetic stirrer. It stirred for 2 hours and obtained the liquid crystal aligning agent (B-5).

<Manufacture of a liquid crystal cell for evaluation of liquid crystal orientation stability and relaxation characteristics of residual DC>

Below, the manufacturing method of the liquid crystal cell for evaluating liquid crystal orientation stability and the relaxation characteristic of residual DC is shown.

A liquid crystal cell equipped with a FFS type liquid crystal display element was manufactured. First, a substrate with attached electrodes was prepared. The substrate is a glass substrate with a size of 30 mm x 35 mm and a thickness of 0.7 mm. On the substrate, an IZO electrode constituting a counter electrode was formed on the entire surface as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed as the second layer by the CVD method was formed. The SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film as the third layer was placed, and two pixels, a first pixel and a second pixel, were formed. The size of each pixel is 10 mm vertically and approximately 5 mm horizontally. 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 has a comb-shaped shape formed by arranging a plurality of く-shaped electrode elements with a bent central portion, as shown in the drawing described in Japanese Patent Application Laid-Open No. 2014-77845. The width of each electrode element in the width direction is 3 μm, and the spacing between electrode elements is 6 μm. Since the pixel electrode forming each pixel is composed of a plurality of く-shaped electrode elements with a curved central portion arranged in an array, the shape of each pixel is not rectangular, but a thick electrode element that is curved in the central portion like the electrode element. It has a shape similar to the letter く in writing. Each pixel is divided into upper and lower parts with the central curved part as a boundary, and has a first area above the curved part and a second area below the curved part.

When comparing the first region and the second region of each pixel, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the direction of the line segment projected on the substrate is based on the polarization plane of polarized ultraviolet rays, which will be described later, in the first area of the pixel, the electrode elements of the pixel electrode are formed at an angle of +10° (clockwise), In the second area of the pixel, the electrode elements of the pixel electrode were formed to form an angle of -10° (clockwise). That is, in the first region and the second region of each pixel, the directions of rotational motion (in-plane switching) of the liquid crystal within the substrate surface caused by voltage application between the pixel electrode and the opposing electrode are opposite to each other. It was structured as possible.

Next, the liquid crystal aligning agent obtained in Synthesis Examples 8 to 12 and Comparative Synthesis Examples 3 to 4 was filtered through a 1.0 μm filter, and then applied to the prepared substrate with an electrode by spin coating. Next, it was dried for 90 seconds on a hot plate set at 70°C. Next, using an exposure apparatus: APL-L050121S1S-APW01 manufactured by Ushio Electric Co., Ltd., linearly polarized ultraviolet light was irradiated through a wavelength selection filter and a polarizing plate in a direction perpendicular to the substrate. At this time, the direction of the polarization plane was set so that the direction of the line segment that projected the polarization plane of the polarized ultraviolet ray onto the substrate was inclined by 10° with respect to the third-layer IZO comb electrode. Subsequently, baking was performed for 30 minutes in an IR (infrared) type oven set at 230°C to obtain an orientation-treated substrate with a polyimide liquid crystal alignment film with a film thickness of 100 nm. Moreover, as an opposing board|substrate, the board|substrate with a polyimide liquid crystal aligning film on which the orientation process was performed similarly to the above was obtained also to the glass substrate which has a columnar spacer with a height of 4 micrometers on which the ITO electrode is formed in the back surface. These two substrates with a liquid crystal alignment film are used as one set, and a sealant is printed on one substrate in a form with a liquid crystal injection port left, and the liquid crystal alignment film surfaces of the other substrate face each other, and the polarization surface of the polarized ultraviolet ray is the substrate. The direction of the projected line segment was made to be parallel and was glued and compressed. Afterwards, the sealant was cured to produce an empty cell with a cell gap of 4 μm. Liquid crystal MLC-7026-100 (negative liquid crystal manufactured by Merck & Co., Ltd.) was injected into this empty cell by a reduced-pressure injection method, the injection port was sealed, and an FFS-type liquid crystal cell was obtained. After that, the obtained liquid crystal cell was heated at 120°C for 30 minutes, left to stand at 23°C overnight, and then used for evaluation of the liquid crystal orientation stability and relaxation characteristics of residual DC.

<Evaluation of liquid crystal orientation stability>

Using the liquid crystal cell, an alternating voltage of 14 VPP was applied at a frequency of 30 Hz in a constant temperature environment of 60°C for 96 hours. After that, the space between the pixel electrode of the liquid crystal cell and the counter electrode was short-circuited, and the liquid crystal cell was left to stand overnight at 23°C.

After leaving, the liquid crystal cell was installed between two polarizing plates arranged so that the polarization axes were orthogonal, the backlight was turned on in a voltage-free state, and the arrangement angle of the liquid crystal cell was adjusted so that the luminance of transmitted light was minimal. And the rotation angle when the liquid crystal cell was rotated from the angle at which the second area of the first pixel became darkest to the angle at which the first area became darkest was calculated as angle Δ. Similarly, in the second pixel, the second area and the first area were compared to calculate the same angle Δ. And the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. When the value of the angle Δ of this liquid crystal cell was less than 0.4°, it was defined as “good”, and when the value of the angle Δ was more than 0.4°, it was defined and evaluated as “bad.”

In addition, the value of the angle Δ when using the liquid crystal aligning agent stored at -20°C for 8 days is Δ[1], and the value of the angle Δ when using the liquid crystal aligning agent stored at 23°C for 8 days is Δ[. 2], and 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 due to storage at 23°C = Δ[2] ÷ Δ[1] × 100

If this value was less than 150, it was defined as “good” and if it was more than 150, it was defined as “poor.”

<Evaluation of relaxation characteristics of residual DC>

The liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal, and the pixel electrode and the opposing electrode are short-circuited and brought to the same potential, and an LED backlight is irradiated from below the two polarizing plates. The angle of the liquid crystal cell was adjusted so that the luminance of the LED backlight transmitted light to be measured was minimized.

Next, while applying a square wave with a frequency of 30 Hz to this liquid crystal cell, the V-T characteristics (voltage-transmittance characteristics) under a temperature of 23°C were measured, and the alternating current voltage at which the relative transmittance was 23% was calculated. Since this alternating voltage corresponds to a region where the change in luminance with respect to voltage is large, it is preferable for evaluating residual DC through luminance.

Next, a square wave with a frequency of 30 Hz was applied for 5 minutes at an alternating voltage with a relative transmittance of 23% at a temperature of 23°C, and then a +1.0 V direct current voltage was applied and driven for 30 minutes. After that, the direct current voltage was cut off, and an alternating voltage with a relative transmittance of 23% was applied again, and only a square wave with a frequency of 30 Hz was applied for 30 minutes.

The faster the relaxation of the accumulated charge, the faster the charge accumulation in the liquid crystal cell when a direct current voltage is applied, so the relaxation characteristic of the residual DC is 30% from the state where the relative transmittance immediately after applying the direct current voltage is 30% or more. It was evaluated by how much the relative transmittance decreased after minutes. That is, when the relative transmittance after 30 minutes of direct current voltage overlap decreased to less than 29%, it was defined as “good”, and when the relative transmittance was 29% or more, it was defined as “poor” and the evaluation was performed.

<Example 1>

A liquid crystal cell was manufactured as described above using two types of liquid crystal aligning agent (A-8) obtained in Synthesis Example 8: one stored at -20°C for 8 days and one stored at 23°C for 8 days. Irradiation of polarized ultraviolet rays was performed using a high-pressure mercury lamp through a wavelength selection filter: 240LCF and a 254 nm type polarizing plate. The amount of polarized ultraviolet rays was measured using an illuminance meter UVD-S254SB manufactured by Ushio Electric Co., Ltd., and changed to 200, 300, 400, 600, 900, 1500, and 2000 mJ/cm2 at a wavelength of 254 nm. By carrying out this, seven liquid crystal cells with different amounts of polarized ultraviolet irradiation were manufactured.

As a result of evaluating the liquid crystal orientation stability of these liquid crystal cells, the polarized ultraviolet irradiation dose with the best angle Δ was 300 mJ/cm2, the angle Δ[1] was 0.18°, and the angle Δ[2] was 0.19°, 23°C. The degree of deterioration of the angle Δ due to preservation was good at 106.

Moreover, the relaxation characteristics of the residual DC of the same polarization ultraviolet irradiation amount previously evaluated before evaluation of liquid crystal orientation stability were good, with a relative transmittance of 26.1% 30 minutes after direct current voltage superimposition.

<Examples 2 to 6>

Except having used the liquid crystal aligning agent obtained in Synthesis Examples 9-13, the liquid crystal orientation stability and the relaxation characteristic of residual DC were evaluated by the same method as Example 1.

<Comparative Examples 1 to 3>

Except having used the liquid crystal aligning agent obtained in comparative synthesis examples 3-5, the liquid crystal orientation stability and the relaxation characteristic of residual DC were evaluated by the same method as Example 1.

About the liquid crystal aligning agent used in Examples 1-6 and Comparative Examples 1-3, the liquid crystal aligning agent containing the polymer shown by (A-a), the liquid crystal aligning agent containing the polymer shown by (A-b), (A-a), and ( Each weight% in the liquid crystal aligning agent containing the polymer represented by A-b) is shown in Table 1.

In Table 2, the polarization ultraviolet irradiation dose at which the angle Δ was the most favorable when using the liquid crystal aligning agent obtained in Examples 1 to 6 and Comparative Examples 1 to 3, the evaluation of liquid crystal orientation stability, and the relaxation characteristics of residual DC are shown. Shows the results of the evaluation.

As shown in Table 1, in Examples 1 to 6, the angle Δ, which is the difference between the orientation azimuth angles before and after the alternating current drive, is less than 0.4° and is good, and the angle Δ deteriorates when the liquid crystal aligning agent is stored at 23° C. for 8 days. The accuracy is good at less than 150, the angle Δ becomes the best with a small polarized ultraviolet irradiation amount of 300 mJ/cm2, and the relative transmittance after 30 minutes of DC voltage superimposition, which shows the relaxation characteristics of residual DC, is good at less than 29.0%, and all are good. Because it has an afterimage characteristic, the display quality of the liquid crystal display device is excellently improved. On the other hand, in Comparative Examples 1 to 3, the angle Δ, the degree of deterioration of the angle Δ when stored at 23°C, the amount of polarized ultraviolet irradiation, and the relative transmittance after 30 minutes of direct current voltage superimposition did not all give good results.

In this way, it was confirmed that the liquid crystal display device manufactured by the method of the present invention exhibits very excellent afterimage characteristics.

The substrate for a transverse electric field driven liquid crystal display device manufactured using the polymer of the present invention, or the transverse electric field driven liquid crystal display device having the substrate, exhibits excellent liquid crystal orientation stability and relaxation characteristics of residual DC with a small amount of polarized ultraviolet irradiation. Therefore, productivity and afterimage characteristics are excellent. Therefore, it can be suitably used in large-screen, high-definition liquid crystal televisions, etc.

Claims (13)

(Aa) Formula (1) below (In formula (1), i is 0 or 1, and It is a group consisting of lene, branched alkylene having 2 to 20 carbon atoms, cyclic alkylene having 3 to 12 carbon atoms, sulfonyl, amide bond, or a combination thereof, where alkylene having 1 to 20 carbon atoms is , may be interrupted by a bond selected from an ester bond and an ether bond, and the carbon atom of phenylene and alkylene is one or more selected from a halogen atom, a cyano group, an alkyl group, a haloalkyl group, an alkoxy group, and a haloalkoxy group. It may be substituted by the same or different substituents.) at least selected from polyamic acids obtained by using a tetracarboxylic dianhydride component containing tetracarboxylic dianhydride and a diamine component and an imidized polymer of the polyamic acid. 1 type of polymer,
(Ab) 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 an imidized polymer of the polyamic acid. at least one type of polymer, and
Contains an organic solvent, and the weight ratio of (Aa) and (Ab) is, (Aa) : (Ab) = 55:
45 ~ 90: 10,
The diamine component of the above (Ab), in addition to the diamine represented by the above formula (2), has the following formula (5) (W ₂ in formula (5) is a divalent organic group, and has the following formula [W ² -19], [W ² -23] ~ [W ² -26], [W ² -39], [W ² -59] ~ [W ² -64], [W ² -67], [W ² -84], [ W ² -86], [W ² -90], [W ² -94], [W ² -95], [W ² -98], [W ² -100], [W ² -113] ~ [W ² -115], [W ² -121] to [W ² -125], [W ² -129], [W ² -137] to [W ² -139], [W ² -141] and [W ² -143]. R ₁ and R ₂ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
A liquid crystal aligning agent having a diamine having a structure represented by .

According to claim 1,
A liquid crystal aligning agent characterized in that 10 to 100 mol% of the tetracarboxylic dianhydride component of the above (Aa) is tetracarboxylic dianhydride represented by the above formula (1). According to claim 1,
A liquid crystal aligning agent characterized in that 10 to 100 mol% of the tetracarboxylic dianhydride component of the above (Ab) is aliphatic tetracarboxylic dianhydride. According to claim 1,
A liquid crystal aligning agent in which 80 to 100 mol% of the tetracarboxylic dianhydride component of the above (Ab) is aliphatic tetracarboxylic dianhydride. According to claim 1,
A liquid crystal aligning agent characterized in that 10 to 100 mol% in the diamine component of the above (Ab) is diamine of formula (2). According to claim 1,
The structure of diamines other than the diamine represented by the above formula (2) is [W ² -60] (however, in [W ² -60], it is limited to the case where n = 2 or n = 4), [W ² -121] (However, in [W ² -121], limited to the case where n = 4), [W ² -129], [W ² -137] to [W ² -139] (However, [W ^2-137 ] to [W ² -139] (limited to the case of n = 2 or n = 4) and [W ² -143]. According to claim 1,
A liquid crystal aligning agent in which the tetracarboxylic dianhydride represented by the formula (1) is at least one selected from pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride. According to claim 1,
A liquid crystal aligning agent wherein the aliphatic tetracarboxylic acid dianhydride is cyclobutanetetracarboxylic acid dianhydride or 1,3-dimethylcyclobutanetetracarboxylic acid dianhydride. [I] A process of applying the liquid crystal aligning agent according to any one of claims 1 to 8 on a substrate having a conductive film for transverse electric field driving to form a coating film;
[II] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I]; and
[III] Process of heating the coating film obtained in [II];
A method for producing a substrate having the liquid crystal alignment film, which obtains a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which orientation control ability is imparted. A liquid crystal alignment film for a transverse electric field driven liquid crystal display element formed from the liquid crystal aligning agent according to any one of claims 1 to 8. A substrate having a liquid crystal alignment film for a transverse electric field driven liquid crystal display element according to claim 10. A transverse electric field driven liquid crystal display device having the substrate according to claim 11. [I] A process of applying the liquid crystal aligning agent according to any one of claims 1 to 8 on a substrate having a conductive film for transverse electric field driving to form a coating film;
[II] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I]; and
[III] Process of heating the coating film obtained in [II];
A process of preparing a substrate (first substrate) having the liquid crystal alignment film, which obtains a liquid crystal alignment film for a transverse electric field driven liquid crystal display element to which orientation control ability is imparted by having;
[I'] A process of applying the liquid crystal aligning agent according to any one of claims 1 to 8 on a second substrate to form a coating film;
[II'] A step of irradiating polarized ultraviolet rays to the coating film obtained in [I']; and
[III'] Process of heating the coating film obtained in [II'];
A process of obtaining a second substrate having the liquid crystal aligning film, which obtains a liquid crystal aligning film to which orientation control ability is imparted by having; and
[IV] A process of obtaining a liquid crystal display element by arranging the first and second substrates to face each other so that the liquid crystal alignment films of the first and second substrates face each other with liquid crystal interposed therebetween;
A method of manufacturing a liquid crystal display device, wherein a transverse electric field driven liquid crystal display device is obtained.