TWI725060B - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal alignment agent, which is used to obtain a liquid crystal alignment film suitable for optical alignment, and even a negative type liquid crystal does not produce bright spots and can obtain good residual image characteristics, and provides the use of the liquid crystal alignment agent. The liquid crystal alignment film of, and the liquid crystal display element provided with the liquid crystal alignment film.

The liquid crystal alignment agent for the photo-alignment method of the present invention contains at least one polymer selected from the group of polyimide precursors and polyimides of the polyimide precursors The polyimide precursor is obtained from a diamine component containing 4 or more types of diamines and tetracarboxylic dianhydride.

Description

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

The present invention relates to a liquid crystal alignment agent for a photo-alignment method, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film.

Liquid crystal display elements used in liquid crystal televisions, liquid crystal displays, etc. are generally equipped with a liquid crystal alignment film for controlling the arrangement state of liquid crystals in the element. As a liquid crystal alignment film, a liquid crystal alignment agent mainly composed of a polyimide precursor such as polyamic acid (also known as polyamide acid) or a solution of soluble polyimide is applied to the glass. A polyimide-based liquid crystal alignment film obtained by firing a substrate, etc. At present, according to the most popular method in the industry, the liquid crystal alignment film is a so-called so-called rubbing in one direction on the surface of the polyimide-based liquid crystal alignment film formed on the electrode substrate with a cloth of cotton, nylon, polyester, etc. It is produced by "rubbing treatment", but it has problems due to the occurrence of inclusions (shavings) generated by the physical contact between the liquid crystal alignment film and the cloth.

On the other hand, the optical alignment method, as a non-friction alignment processing method, also has the advantage of being produced by a simple manufacturing process in the industry. Click (Non-Patent Document 1). As the liquid crystal alignment agent used in the photo-alignment method, a liquid crystal alignment treatment method by light irradiating a polyimide-based liquid crystal alignment film has been proposed (refer to Patent Document 1). Especially, in the liquid crystal display element of the IPS driving method or the fringe electric field switching (hereinafter referred to as FFS) driving method, by using the liquid crystal alignment film obtained by the photo-alignment method, compared with the liquid crystal alignment film obtained by the rubbing method In other words, it can be expected that the contrast or viewing angle characteristics of the liquid crystal display element can be improved, and the performance of the liquid crystal display element can be improved.

However, the liquid crystal alignment film obtained by the photo-alignment method has the problem that the anisotropy of the so-called polymer film with respect to the alignment direction is small compared to the liquid crystal alignment film obtained by the rubbing treatment. If the anisotropy is small, sufficient liquid crystal alignment cannot be obtained, and when it is used as a liquid crystal display element, problems such as image sticking will occur. In addition, as a method of improving the anisotropy of the liquid crystal alignment film obtained by the photo-alignment method, it has been proposed that after light irradiation, the polyimide main chain is cut due to light irradiation and the resulting low Molecular weight component (refer to Patent Document 2).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-297313

[Patent Document 2] JP 2011-107266 A

[Non-Patent Document 1] "Liquid Crystal Optical Alignment Film" Kidowaki, Ichimura Functional Materials November 1997, Vol.17 No.11, pages 13-22

In the liquid crystal display element of the IPS driving method or the FFS driving method, a positive liquid crystal has been used in the past. However, with the high definition of liquid crystal display elements in recent years, the use of a negative liquid crystal has attracted attention. By using negative-type liquid crystals, the transmission loss at the top of the electrode can be reduced and the contrast can be improved. The use of the liquid crystal alignment film obtained by the photo-alignment (processing) method in a liquid crystal display element of an IPS driving method or an FFS driving method using negative liquid crystals can be expected to have higher display performance than conventional liquid crystal display elements.

However, the inventor of the present invention found through the results of the review: "In the case of liquid crystal display elements using negative liquid crystals, the occurrence rate of display defects (bright spots) of the liquid crystal alignment film obtained by the photo-alignment method is high. The display failure is caused by the decomposition product of the polymer constituting the liquid crystal alignment film caused by the irradiation of polarized ultraviolet light."

The subject of the present invention is to provide a liquid crystal alignment agent suitable for photo-alignment method processing, which is used to obtain a liquid crystal alignment film for photo-alignment (processing) method, and even when a negative type liquid crystal is used, bright spots are not generated. In addition, good residual image characteristics can be obtained, and a liquid crystal alignment film obtained from the liquid crystal alignment agent and a liquid crystal display element provided with the liquid crystal alignment agent can be provided.

In the liquid crystal display element, in terms of illumination sensitivity or afterimage characteristics, etc. The reason for the poor display of the surface is the generation of bright spots. In order to solve the above problems, the inventors have conducted in-depth and repeated research and found that the bright spots in such a liquid crystal display element can be aligned by the following liquid crystal The liquid crystal alignment agent contains the polyimide precursor obtained by the reaction of the "diamine component" and the "tetracarboxylic acid derivative" and/or the polyimide precursor An imidized polyimide, the diamine component contains 4 or more types (preferably 5 or more, more preferably 6 or more) diamines with different structures, used as a liquid crystal alignment agent. The diamine of the polyimide precursor and the polyimide precursor of the polyimide precursor is formed.

The present inventor completed the present invention based on this.

The reason why the above-mentioned problems of the present invention can be solved by the present invention is not yet clear, but it can be roughly estimated as follows.

The liquid crystal alignment film obtained from the liquid crystal alignment agent having the constitution of the present invention is subjected to alignment treatment by light or the like, and at this time, decomposition products having 4 or more different structures are generated. The respective decomposition products have different dissolution limits for the liquid crystal system. When the amount of decomposition products of the same structure increases, the amount of dissolution limit for liquid crystals is exceeded and precipitates, which becomes the cause of bright spots. However, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is irradiated with light. , The decomposition products produced are of various types but a small amount, and will not exceed the dissolution limit for liquid crystals.

The inventors of the present invention have confirmed through the results of many inspections that even if it is a decomposition product with a structure that has the lowest solubility for liquid crystals, if the diamine derived from this structure is 30 mol% or less of the total diamine component ( More When it is preferably 25 mol% or less, more preferably 20 mol% or less), even when light is irradiated to a liquid crystal alignment film obtained from a liquid crystal alignment agent containing the polymer, the resulting liquid crystal display element No bright spots will be produced.

According to the present invention, a liquid crystal alignment agent suitable for photo-alignment processing can be provided, which can suppress the bright spots seen in the conventional alignment processing method, has high irradiation sensitivity, and can obtain a liquid crystal alignment film with good afterimage characteristics. By providing a liquid crystal alignment film obtained from such a liquid crystal alignment agent, it is possible to provide a liquid crystal display element with no display defects and high reliability.

[Best form to implement the invention]

The liquid crystal alignment agent of the present invention, as described above, is a polymerization of at least one polyimide selected from the group of polyimide precursors and polyimide compounds of the polyimide precursors The polyimide precursor is obtained by reacting a diamine component containing 4 or more types of diamines with a tetracarboxylic acid derivative.

<Specific polymer>

The polyimide precursor of the "specific polymer" contained in the liquid crystal alignment agent of the present invention can be represented by the following formula (1).

In the formula (1), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative. Y ₁ is a divalent organic group derived from diamine. R ₁ represents a hydrogen atom or an alkylene group having 1 to 5 carbon atoms. From the viewpoint of the ease of the imidization reaction, R _{1 is} preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

A ₁ and A ₂ are each independently a hydrogen atom, an alkyl group with 1 to 5 carbons, an alkenyl group with 2 to 5 carbons, or an alkynyl group with 2 to 5 carbons. From the viewpoint of liquid crystal alignment, A ₁ and A _{2 are} preferably hydrogen atoms or methyl groups.

<Diamine>

The diamine component used in the liquid crystal alignment agent of the present invention contains 4 or more types, preferably 5 or more types, and more preferably 6 or more types of diamines. In addition, the "type" here means the structure in the diamine, that is, the so-called four or more types of diamines means four or more diamines with different structures. The larger the type of diamine component, the better, but the manufacturing and management will be troublesome. Therefore, it is preferably 10 types or less, more preferably 7 types or less, and more preferably 5 types or less.

Still, the so-called diamine components are more than 4 types, which means that they are derived from The diamine of this structure is 30 mol% or less of the total diamine component, preferably 25 mol% or less, and more preferably 20 mol% or less. Of course, the diamine from each structure does not need to be contained in the same amount in the total diamine, and may contain different amounts respectively. Moreover, if the content of the diamine from each structure is too small, production and management will become troublesome, so it is preferably 1 mol% or more, and more preferably 5 mol% or more.

The diamine used in the polymerization of the polymer having the structure of the above formula (1) can be represented by the following formula (2). When exemplifying _{the structure of Y 1} , it is as follows.

(2) In the above formula, A ₁ and also comprising a preferred embodiment of A _2, A system with the above-described formula (1) A ₁ and ₂ is the same as defined above.

From the viewpoint of liquid crystal orientation, Y _{1 is} preferably a structure with high linearity, and examples thereof include a structure represented by the following formula (8) or the following formula (9).

In the above formulas (8) and (9), A ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms. A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphoric acid group, or a monovalent organic group with 1 to 20 carbon atoms. a is an integer from 1 to 4. When a is 2 or more, _{the structure of A 1} may be the same or different. b and c are each independently an integer of 1~2.

As specific examples of the above formula (8) and the above formula (9), for example, Y-7, Y-25, Y-26, Y-27, Y-43, Y-44, Y-45, Y-46 , Y-48, Y-71, Y-72, Y-73, Y-74, Y-75, Y-76, Y-82, Y-87, Y-88, Y-89, Y-90, Y -92, Y-93, Y-94, Y-95, Y-96, Y-100, Y-101, Y-102, Y-103, Y-104, Y-105, Y-106, Y-110 , Y-111, Y-112, Y-113, Y-115, Y-116, Y-121, Y-122, Y-126, Y-127, Y-128, Y-129, Y-132, Y -134, Y-153, Y-156, Y-157, Y-158, Y-159, Y-160, Y-161, Y-162, Y-163, Y-164, Y-165, Y-166 , Y-167, and Y-168.

From the viewpoint of the so-called improvement of the solubility of the polymer, _{the structure of Y 1} preferably includes a structure represented by the following formula (7).

In the above formula (7), D is t-butoxycarbonyl.

Specific examples of Y1 including the structure represented by the above formula (7) include Y-158, Y-159, Y-160, Y-161, Y-162, and Y-163.

<Tetracarboxylic acid derivatives>

As the tetracarboxylic acid derivative component contained in the liquid crystal alignment agent of the present invention (which is used to produce a polymer having the structural unit of the above formula (1)), in addition to tetracarboxylic dianhydride, tetracarboxylic acid can also be used Acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide.

As the tetracarboxylic acid derivative, tetracarboxylic dianhydride having photoreactivity is preferable, and among them, tetracarboxylic dianhydride represented by the following formula (3) is more preferable.

In the formula (3), X ₁ is a tetravalent organic group having an alicyclic structure, and specific examples include the following formulas (X1-1) to (X1-10).

In formulas (X1-1)~(X1-4), R ₃ ~R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group with a carbon number of 1 to 6, an alkenyl group with a carbon number of 2 to 6, and a carbon number of 2 to 6-alkynyl group, fluorine atom-containing monovalent organic group with 1 to 6 carbon atoms, or phenyl group. From the viewpoint of liquid crystal alignment, R ₃ to R ₂₃ are preferably hydrogen atoms, halogen atoms, methyl groups, or ethyl groups, and more preferably hydrogen atoms or methyl groups. As a specific structure of the formula (X1-1), the following formulas (X1-11) to (X1-16) can be given. From the viewpoint of liquid crystal orientation and photoreaction sensitivity, (X1-11) is particularly preferred.

The tetracarboxylic dianhydride used in the present invention may be tetracarboxylic dianhydride represented by the following formula (4) in addition to the above formula (3).

In formula (4), X ₂ is a tetravalent organic group, and the structure is not particularly limited. If a specific example is given, the structure of the following expressions (X-9) to (X-42) can be given. From the viewpoint of the availability of compounds, the structure of X can include X-17, X-25, X-26, X-27, X-28, X-32, X-35, X-37, and X- 39. In addition, from the viewpoint of obtaining a liquid crystal alignment film in which the residual charge accumulated by the DC voltage is relaxed quickly, it is preferable to use tetracarboxylic dianhydride having an aromatic ring structure, and X is X-26, X- 27, X-28, X-32, X-35, or X-37 are more preferred.

The tetracarboxylic acid derivative, which is the raw material of the polyimide precursor and polyimine of the present invention, is derived from the tetracarboxylic acid represented by the above formula (3) with respect to 1 mol of all tetracarboxylic acid derivatives The content is preferably 60-100 mol%. In order to obtain a liquid crystal alignment film with good liquid crystal alignment, 80 mol%-100 mol% is more preferable, and 90 mol%-100 mol% is more preferable.

<Manufacturing method of polyamide ester>

The polyimide precursors and polyamide esters used in the present invention can be synthesized according to the methods (1), (2) or (3) shown below.

(1) In the case of synthesis from polyamide acid

The polyamide ester system can be synthesized by esterifying polyamide acid obtained from tetracarboxylic dianhydride and diamine.

Specifically, the polyamide acid and the esterification agent can be heated 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 ~4 hours reaction to synthesize.

As the above-mentioned esterification agent, those that can be easily removed by purification are preferred, and examples include N,N-dimethylformamide dimethyl acetal and N,N-dimethylformamide Diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide Methamide 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 addition amount of the esterification agent is preferably 2 to 6 molar equivalents with respect to 1 mol of the repeating unit of polyamide acid.

The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone in terms of the solubility of the polymer. Use 1 type or mix 2 or more types to use. The concentration at the time of synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that it is difficult to cause precipitation of the polymer and easy to obtain a polymer.

(2) In the case of synthesis by the reaction of tetracarboxylic acid diester dichloride and diamine

Polyurethane can be synthesized from tetracarboxylic acid diester dichloride and diamine.

Specifically, tetracarboxylic acid diester dichloride and diamine can be used in the presence of alkali and 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 for synthesis.

As the aforementioned base system, pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used, but pyridine is preferred for the stable progress of the reaction. The addition amount of the base is preferably 2 to 4 times mol relative to the tetracarboxylic acid diester dichloride in terms of an amount that can be easily removed and that a polymer can be easily obtained.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in terms of the solubility of monomers and polymers. These systems can be used singly or as a mixture of two. Use the above. The polymer concentration at the time of synthesis is preferably 1-30% by mass, and more preferably 5-20% by mass, from the viewpoint that it is difficult to cause precipitation of the polymer and easy to obtain a polymer. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the synthesis of the polyamide ester is preferably dehydrated as much as possible. In order to prevent the mixing of external air, the solvent should be carried out in a nitrogen environment. Better.

(3) In the case of synthesizing polyamide ester from tetracarboxylic acid diester and diamine

Polyurethane can be synthesized by polycondensation of tetracarboxylic acid diester and diamine. Specifically, the tetracarboxylic acid diester and diamine can be used 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 to 15 hours for synthesis.

唑基硫基)膦酸二苯酯等。縮合劑的添加量，相對於四羧酸二酯以2~3倍莫耳為較佳。 The aforementioned condensing agent system can use triphenyl phosphite, dicyclohexyl carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, N ,N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinemethylmorpholine, O-(benzotriazol-1-yl)-N,N,N',N'- Tetramethylurea tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethylurea hexafluorophosphate, (2,3-di Hydrogen-2-sulfanyl-3-benzo

Azolylthio) diphenyl phosphonate and the like. The addition amount of the condensing agent is preferably 2 to 3 times mol relative to the tetracarboxylic acid diester.

As the aforementioned base system, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 times mol relative to the diamine component in terms of an amount that can be easily removed and that a polymer can be easily obtained.

In addition, in the above-mentioned reaction, by adding a Lewis acid as an additive, the reaction can proceed efficiently. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferred. The addition amount of the Lewis acid is preferably 0 to 1.0 times mol relative to the diamine component.

Among the three methods for synthesizing polyamides, in order to obtain high-molecular-weight polyamides, the synthesis method of (1) or (2) is particularly preferred.

The solution of the polyamide ester obtained in the manner described above can be poured into the poor solvent while stirring, so that the polymer can be precipitated. After several times of precipitation and washing with a poor solvent, a refined polyamide ester powder can be obtained after drying at room temperature or by heating. The poor solvent is not particularly limited, but water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. can be mentioned.

<Manufacturing method of polyamide acid>

The polyimide precursor of the polyimide used in the present invention can be synthesized according to the method shown below.

Specifically, by making tetracarboxylic dianhydride and diamine 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 12 hours reaction to synthesize.

For the organic solvent used in the above reaction, in terms of the solubility of monomers and polymers, N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone are more Preferably, one of these systems can be used or two or more of them can be mixed for use. The concentration of the polymer is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass, from the viewpoint that it is difficult to cause precipitation of the polymer and easily obtains a polymer.

The polyamide acid obtained in the above-mentioned manner can be precipitated and recovered by injecting the reaction solution into the poor solvent while sufficiently stirring the reaction solution. In addition, after several times of precipitation and washing with a poor solvent, it is dried at room temperature or by heating to obtain a purified polyamide acid powder. The poor solvent is not particularly limited, but water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc. can be mentioned.

<Manufacturing Method of Polyimide>

The polyimide system used in the present invention can be produced by imidizing the aforementioned polyamide ester or polyamide acid. When the polyimide is produced from polyamide, it is necessary to add the aforementioned polyamide solution or polyamide The chemical imidization of the polyamide acid solution obtained by dissolving the acid ester resin powder in an organic solvent with a basic catalyst is simple. Since the chemical imidization system proceeds at a relatively low temperature, it is difficult to cause the molecular weight of the polymer to decrease during the imidization process, so it is preferred.

The chemical imidization is performed by stirring the polyamide to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent system, the solvent used in the aforementioned polymerization reaction can be used. As a basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. are mentioned. Among them, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of the alkaline catalyst is 0.5 to 30 mol times of the amide acid ester group, preferably 2 to 20 mol times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the solution after the imidization reaction remains with the added catalyst, etc., the obtained imidization polymer is recovered by the following means, and re-dissolved in an organic solvent, thus making the cost invention The liquid crystal alignment agent is preferred.

In the case of producing polyimide from polyamic acid, the chemical imidization of adding a catalyst to the polyimide solution obtained by the reaction of the diamine component and tetracarboxylic dianhydride is Simple. Since the chemical imidization system proceeds at a relatively low temperature, it is difficult to cause the molecular weight of the polymer to decrease during the imidization process, so it is preferred.

Chemical imidization is achieved by The polymer is stirred in the presence of a basic catalyst and an acid anhydride in an organic solvent. As the organic solvent system, the solvent used in the aforementioned polymerization reaction can be used. As a basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. are mentioned. Among them, pyridines are preferred because they have moderate basicity to allow the reaction to proceed. Moreover, as an acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic dianhydride, etc. can be mentioned, Especially, when acetic anhydride is used, the purification after completion|finish of reaction becomes easy, and it is preferable.

The temperature during the imidization reaction is -20°C to 140°C, preferably 0°C to 100°C, and the reaction time is 1 to 100 hours. The amount of alkaline catalyst is 0.5 to 30 molar times of the amide acid group, preferably 2 to 20 molar times, and the amount of acid anhydride is 1 to 50 molar times of the amide acid group, preferably 3 to 3 molar times. 30 mol times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

In the solution after the imidization reaction of polyamide or polyamide, the added catalyst and the like remain in the solution, so the obtained imidization polymerization is recovered by the following means It is preferably used as the liquid crystal alignment agent of the present invention for re-dissolving in an organic solvent.

The polyimide solution obtained in the above-mentioned manner is poured into the poor solvent while fully stirring, so that the polymer can be precipitated. After several times of precipitation and washing with a poor solvent, after drying at room temperature or by heating, a refined polyamide ester powder can be obtained.

The said poor solvent is not specifically limited, but methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, etc. are mentioned.

<Liquid crystal alignment agent>

The liquid crystal alignment agent used in the present invention is in the form of a solution in which a polymer with a specific structure is dissolved in an organic solvent. The molecular weight of the polyimide precursor and polyimine described in the present invention is preferably 2,000 to 500,000 in terms of weight average molecular weight, more preferably 5,000 to 300,000, and more preferably 10,000 to 100,000. In addition, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and more preferably 5,000 to 50,000.

The polymer concentration of the liquid crystal alignment agent used in the present invention can be appropriately changed according to the setting of the thickness of the coating film to be formed. In terms of forming a uniform and defect-free coating film, it is 1% by weight or more. Preferably, in terms of storage stability of the solution, 10% by weight or less is preferable.

The solvent used in the liquid crystal alignment agent of the present invention is not particularly limited as long as it is a solvent (also referred to as a good solvent) that can dissolve the polyimide precursor and polyimine described in the present invention. Specific examples of good solvents are given below, but they are not limited to these examples.

For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfide, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone or 4-hydroxy-4-methyl-2-pentanone, etc. Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone.

Furthermore, regarding the polyimide precursor and polyimide described in the present invention When the solubility of the solvent is high, it is better to use the solvent represented by the following formula [D-1] to formula [D-3].

(In formula [D-1], D ¹ represents an alkyl group with 1 to 3 carbons, in formula [D-2], D ² represents an alkyl group with 1 to 3 carbons, in formula [D-3], D ³ represents an alkyl group with 1 to 4 carbon atoms).

The good solvent in the liquid crystal alignment agent is preferably 20 to 99% by mass of the total solvent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

In the range that does not impair the effect of the present invention, the liquid crystal alignment agent may contain a solvent (also referred to as a poor solvent) that improves the coating property or surface smoothness of the liquid crystal alignment film when the liquid crystal alignment agent is applied. These poor solvents are preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent. Among them, 10 to 80% by mass is preferable. It is more preferably 20 to 70% by mass.

Specific examples of poor solvents can be given below, but they are not limited to these examples. Examples include ethanol, isopropanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl -1-butanol, isoamyl alcohol, tert-pentanol, 3-methyl-2-butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2 -Pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2- Ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethylene glycol, 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, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethyl Glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl Base ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1- Methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, propylene carbonate Ethyl, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, Diethylene glycol, propylene glycol, 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, ethyl 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, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3 -Methoxypropionic acid Ethyl ester, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl ester, 3-methoxypropionic acid butyl ester, methyl lactate, ethyl lactate, lactic acid n- Propyl ester, n-butyl lactate, isoamyl lactate, or the solvent represented by the aforementioned formula [D-1] to formula [D-3], etc.

Among them, 1-hexanol, cyclohexanol, 1,2-ethylene glycol, 1,2-propylene glycol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetic acid Esters or dipropylene glycol dimethyl ether are preferred.

In the liquid crystal alignment agent of the present invention, a crosslinkable compound selected from an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group, and a lower alkoxy group are introduced. A crosslinkable compound having at least one substituent of the group consisting of a radical alkyl group or a crosslinkable compound having a polymerizable unsaturated bond is preferable. These substituents or polymerizable unsaturated bonds need to have two or more in the crosslinkable compound.

Examples of crosslinkable compounds having epoxy groups or isocyanate groups include bisphenol acetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, and tetraglycidyl. Glycerylamino diphenylene, tetraglycidyl-m-xylene diamine, tetraglycidyl-1,3-bis(aminoethyl)cyclohexane, tetraphenylglycidyl ether ethane, Triphenyl glycidyl ether ethane, bisphenol hexafluoroacetone diglycidyl ether, 1,3-bis(1-(2,3-epoxypropoxy)-1-trifluoromethyl-2,2 ,2-Trifluoromethyl)benzene, 4,4-bis(2,3-glycidoxy)octafluorobiphenyl, triglycidyl-p-aminophenol, tetraglycidyl m-xylene Amine, 2-(4-(2,3-glycidoxy)phenyl)-2-(4-(1,1-bis(4-(2,3-glycidoxy)phenyl) Ethyl)phenyl)propane or 1,3-bis(4-(1-(4- (2,3-glycidoxy)phenyl)-1-(4-(1-(4-(2,3-glycidoxy)phenyl)-1-methylethyl)phenyl )Ethyl)phenoxy)-2-propanol and the like.

The crosslinkable compound having an oxetane group is a compound having at least two oxetane groups represented by the following formula [4A].

Specifically, the cross-linkable compound represented by formula [4a] to formula [4k] described on pages 58 to 59 of International Publication WO2011/132751 (2011.10.27 publication) can be cited.

The crosslinkable compound having a cyclic carbonate group is a crosslinkable compound having at least two cyclic carbonate groups represented by the following formula [5A].

Specifically, the cross-linkable compound represented by formula [5-1] to formula [5-42] described on pages 76 to 82 of International Publication WO2012/014898 (2012.2.2 publication) can be cited.

As having at least 1 selected from the group consisting of hydroxyl and alkoxy A crosslinkable compound with a kind of substituent, for example, an amine-based resin having a hydroxyl group or an alkoxy group, for example, melamine resin, urea resin, guanamine resin, glycoluril-formaldehyde resin, succinamide-formaldehyde resin or sub Ethylurea-formaldehyde resin, etc. Specifically, a melamine derivative, a benzoguanamine derivative, or an acetylene carbamide in which the hydrogen atom of the amino group is substituted with a methylol group or an alkoxymethyl group or both of them can be used. The melamine derivative or benzoguanamine derivative system may also exist as a dimer or a trimer. These systems preferably have 3 to 6 hydroxymethyl groups or alkoxymethyl groups per triazine ring on average.

As an example of the above-mentioned melamine derivative or benzoguanamine derivative, there can be mentioned commercially available MX-750 in which each triazine ring is substituted by an average of 3.7 methoxymethyl groups, and each triazine ring MW-30 (above, manufactured by Sanwa Chemical Co., Ltd.) or CYMEL300, 301, 303, 350, 370, 771, 325, 327, 703, 712, etc., substituted by an average of 5.8 methoxymethyl groups Alkylated melamine, CYMEL235, 236, 238, 212, 253, 254, etc., butoxymethylated butoxymethylated melamine, CYMEL506, 508, etc., butoxymethylated melamine, CYMEL1141, etc., containing carboxyl groups Methoxymethylated isobutoxymethylated melamine, methoxymethylated ethoxymethylated benzoguanamine such as CYMEL1123, methoxymethylated butyl such as CYMEL1123-10 Oxymethylated benzoguanamine, butoxymethylated benzoguanamine such as CYMEL1128, carboxy-containing methoxymethylated ethoxymethylated benzoguanamine such as CYMEL1125-80 (Above, manufactured by Mitsui Cyanamid). Also, as examples of acetylene carbamides, butoxymethylated acetylene carbamides such as CYMEL1170 and CYMEL1172 Class hydroxymethylated acetylene carbamide, etc., and methoxymethylated acetylene carbamide such as Powderlink 1174.

Examples of benzene or phenolic compounds having a hydroxyl group or an alkoxy group include 1,3,5-gins(methoxymethyl)benzene, 1,2,4-gins(isopropoxymethyl)benzene , 1,4-bis(sec-butoxymethyl)benzene or 2,6-dihydroxymethyl-p-tert-butylphenol.

More specifically, the cross-linkable compound of formula [6-1] to formula [6-48] published on pages 62 to 66 of International Publication WO2011/132751 (2011.10.27 publication).

As a crosslinkable compound having a polymerizable unsaturated bond, for example, trimethylolpropane tri(meth)acrylate, neopentylerythritol tri(meth)acrylate, dineopentylerythritol penta(meth)acrylate, Base) acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, or glycerol polyglycidyl ether poly(meth)acrylate, etc., which have 3 polymerizable unsaturated groups in the molecule Crosslinking compounds, moreover, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate )Acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide Bisphenol A type di(meth)acrylate, propylene oxide bisphenol type di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerol di(meth)acrylate, Neopentylerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid dihydrate Glyceride di(meth)acrylate or hydroxytrimethylacetate neopentyl glycol di(meth)acrylate and other crosslinkable compounds having 2 polymerizable unsaturated groups in the molecule, and 2-hydroxyl Ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate , 2-(meth)acryloxy-2-hydroxypropyl phthalate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerol mono(meth)acrylate, Crosslinkable compounds having one polymerizable unsaturated group in the molecule, such as 2-(meth)acryloyloxyethyl phosphate or N-methylol(meth)acrylate amide.

Furthermore, the compound represented by following formula [7A] can also be used.

(In formula [7A], E ₁ represents selected from the group consisting of cyclohexane ring, bicyclohexane ring, benzene ring, biphenyl ring, terphenyl ring, naphthalene ring, sulphur ring, anthracene ring or phenanthrene ring E ₂ represents a group selected from the following formula [7a] or formula [7b], and n represents an integer of 1 to 4).

An example of the above-mentioned crosslinkable compound is not limited to these. In addition, the crosslinking compound used in the liquid crystal alignment agent of the present invention One type may be used, or two or more types may be combined.

The content of the crosslinkable compound in the liquid crystal alignment agent of the present invention is preferably 0.1 to 150 parts by mass relative to 100 parts by mass of the total polymer components. Among them, in order to perform the crosslinking reaction and exhibit the intended effect, it is preferably 0.1 to 100 parts by mass relative to 100 parts by mass of the total polymer components. It is more preferably 1 to 50 parts by mass.

As long as the liquid crystal alignment agent of the present invention does not impair the effects of the present invention, a compound that improves the uniformity or surface smoothness of the film thickness of the liquid crystal alignment film when the liquid crystal alignment agent is applied can be used.

Examples of compounds that improve the uniformity or surface smoothness of the film thickness of the liquid crystal alignment film include fluorine-based surfactants, polysiloxane-based surfactants, and nonionic surfactants.

More specifically, for example, F-Top EF301, EF303, EF352 (above, manufactured by Tokem Products), MEGAFACE F171, F173, R-30 (above, manufactured by Dainippon Ink Co., Ltd.), Fluorad FC430, FC431 (above , Sumitomo 3M Corporation), AashiGuard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass), etc.

The amount of the surfactant used is preferably 0.01 to 2 parts by mass, and more preferably 0.01 to 1 part by mass relative to 100 parts by mass of all polymer components contained in the liquid crystal alignment agent.

Moreover, as a compound that promotes the movement of charges in the liquid crystal alignment film and promotes the release of the charge of the device, the liquid crystal alignment agent can also be added The nitrogen-containing heterocyclic amine compounds represented by formula [M1] to formula [M156] are published on pages 69 to 73 of International Publication WO2011/132751 (2011.10.27 publication). The amine compound can also be directly added to the liquid crystal alignment agent, and it is better to add it later as a solution with a concentration of 0.1-10% by mass (preferably 1-7% by mass). The solvent is not particularly limited as long as it can dissolve the specific polymer (A).

Except for the above-mentioned poor solvent, crosslinkable compound, resin film or liquid crystal alignment film thickness uniformity or surface smoothness of the compound and promote the release of charge, as long as the scope of the effect of the present invention is not impaired Within the liquid crystal alignment agent of the present invention, polymers other than the polymers described in the present invention can also be added to improve the adhesion between the alignment film and the substrate. The silane coupling agent is further used when firing the coating film. The polyimide precursor is heated to make the imidization more effectively proceed as an imidization accelerator, etc.

<Liquid crystal alignment film, liquid crystal display element>

The liquid crystal alignment film is a film obtained by coating the above-mentioned liquid crystal alignment agent on a substrate, drying and firing. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as acrylic substrates or polycarbonate substrates can also be used for glass substrates and silicon nitride substrates. In this case, it is preferable to use a substrate on which ITO electrodes for driving liquid crystals are formed, in terms of simplification of the manufacturing process. In addition, in reflective liquid crystal display elements, but only for one side of the substrate, opaque materials such as silicon wafers can be used, and the electrodes in this case can also be used Materials that reflect light such as aluminum.

The coating method of the liquid crystal alignment agent is not particularly limited, but the industrial method is generally performed by screen printing, offset printing, flexographic printing, or inkjet method. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spinner method, a spray method, etc., and these can also be used according to the purpose.

After the liquid crystal alignment agent is coated on the substrate, the solvent is evaporated by heating means such as a heating plate, a thermal cycle oven or an IR (infrared) oven, which can be used as a liquid crystal alignment film. In the drying and firing steps after coating the liquid crystal alignment agent of the present invention, any temperature and time can be selected. Generally, in order to sufficiently remove the contained solvent, it is usually fired at 50 to 120°C for 1 to 10 minutes, and then at 150 to 300°C for 5 to 120 minutes. If the thickness of the sintered liquid crystal alignment film is too thin, the reliability of the liquid crystal display element may be reduced, so 5~300nm is preferred, and 10~200nm is even more preferred.

The alignment treatment method of the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is a photo-alignment treatment method. As a preferable example of the photo-alignment treatment method, the surface of the aforementioned liquid crystal alignment film may be irradiated with polarized radiation in a certain direction, and depending on the situation, it is preferable to perform a heat treatment at a temperature of 150 to 250°C to give liquid crystal alignment. Performance (also known as liquid crystal alignment energy) method. As the radiation, ultraviolet rays or visible rays having a wavelength of 100 to 800 nm can be used. Among them, it is preferably 100 to 400 nm, and more preferably ultraviolet light having a wavelength of 200 to 400 nm.

In addition, in order to improve the liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be irradiated with radiation while being heated at 50 to 250°C. In addition, the irradiation amount of the aforementioned radiation is preferably ^{1 to 10,000 mJ/cm 2.} Among them, 100 to 5,000 mJ/cm ² is preferred. The liquid crystal alignment film made in such a way can stably align the liquid crystal molecules in a certain direction.

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

Furthermore, according to the aforementioned method, the liquid crystal alignment film irradiated with polarized radiation can also be contacted with water or a solvent.

The solvent used in the above-mentioned contact treatment may be a solvent that dissolves the decomposition product generated from the liquid crystal alignment film by irradiation with radiation, and is not particularly limited. 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, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate or cyclohexyl acetate, etc. . Among them, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate is preferable in terms of generality or solvent safety. It is also preferably water, 1-methoxy-2-propanol or ethyl lactate. One type of solvent may be used, or two or more types may be combined.

The above-mentioned contact treatment, that is, water or solvent treatment of the liquid crystal alignment film irradiated with polarized radiation, includes immersion treatment or spray treatment (also referred to as spray treatment). The treatment time in these treatments is to use radiation to make the decomposition products generated by the liquid crystal alignment film effective In terms of the point of dissolution, 10 seconds to 1 hour is preferable. Among them, it is preferable to perform the immersion treatment for 1 minute to 30 minutes. In addition, the solvent during the aforementioned contact treatment may be heated at room temperature, and it is preferably 10 to 80°C. Among them, 20-50°C is preferred. In addition, in terms of the solubility of the decomposed product, ultrasonic treatment can also be performed as needed.

After the aforementioned contact treatment, washing with low boiling point solvents such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone (also called wetting) or burning of the liquid crystal alignment film is performed. good. At this time, either of wetting and firing may be performed, or both may be performed. The sintering temperature is preferably 150~300℃. Among them, 180~250°C is preferred. It is more preferably 200~230°C. In addition, the firing time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferred.

The liquid crystal alignment film of the present invention can be suitably used as a liquid crystal alignment film of a liquid crystal display device of a lateral electric field method such as an IPS method or an FFS method, and is particularly useful as a liquid crystal alignment film of a liquid crystal display device of the FFS method. The liquid crystal display element is obtained from the liquid crystal alignment agent of the present invention and after obtaining a substrate with a liquid crystal alignment film, a liquid crystal cell is fabricated according to a known method and obtained by using the liquid crystal cell.

As an example of a method of manufacturing a liquid crystal cell, a liquid crystal display element with a passive matrix structure will be described as an example. Furthermore, in each pixel portion constituting the image display, there may be a liquid crystal display element of an active matrix structure provided with a switching element such as TFT (Thin Film Transistor).

Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be used as ITO electrodes, for example, and formed into a pattern capable of displaying a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film system can be used as, for example, a SiO ₂ -TiO ₂ film formed by a sol-gel method.

Next, a liquid crystal alignment film is formed on each substrate, and the other substrate is overlapped on one substrate so that the liquid crystal alignment film faces face each other, and the periphery is bonded with a sealant. In order to control the substrate gap, it is generally possible to mix spacers in the sealant, and it is also preferable to spread spacers for substrate gap control on the in-plane portion where the sealant is not provided. A part of the sealing compound may be provided with an opening that can be filled with liquid crystal from the outside. Next, through the opening provided in the sealant, a liquid crystal material is injected into the space surrounded by the two substrates and the sealant, and then the opening is sealed with an adhesive. The injection system can use a vacuum injection method, or a method that uses capillary phenomenon in the atmosphere. The liquid crystal material can be either a positive liquid crystal material or a negative liquid crystal material, but the preferred one is a negative liquid crystal material. Next, set up the polarizing plate. Specifically, a pair of polarizing plates are pasted on the surface opposite to the liquid crystal layer of the two substrates.

[Example]

Examples are given below to illustrate the present invention more specifically, but the present invention is not limited to these. In the following, the abbreviated symbols of the compounds and the measurement methods of each characteristic are as follows.

NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone NEP: N-Ethyl-2-pyrrolidone, BCS: Butyl Cellosolve PB: Propylene Glycol Monobutyl Ether, Additive A: N-α-(9-Tunylmethoxycarbonyl)-N-τ-t-Butoxy Carbonyl-L-histidine, ADA-0: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

The measuring methods of each characteristic used in the examples are as follows.

[Molecular Weight]

In addition, the molecular weight of the polyamide ester is measured by a GPC (normal temperature gel permeation chromatography) device, and the number average molecular weight (also referred to as Mn) is calculated in terms of polyethylene glycol and polyethylene oxide conversion values. And the weight average molecular weight (also known as Mw).

GPC device: manufactured by Shodex Corporation (GPC-101)

Column: manufactured by Shodex (series connection of KD803 and KD805)

Column temperature: 50℃

Eluent: N,N-dimethylformamide (as an additive, lithium bromide-hydrate (LiBr‧H ₂ O) is 30mmol/L, phosphoric acid‧anhydrous crystal (o-phosphoric acid) is 30mmol/L, tetrahydrofuran (THF) ) Is 10ml/L)

Flow rate: 1.0ml/min

Standard samples for making calibration lines: TSK standard polyethylene oxide manufactured by Tosoh (weight average molecular weight (Mw) approximately 900,000, 150,000, 100,000, 30,000), and polyethylene glycol manufactured by Polymer Laboratories (peak top molecular weight (Mp) ) About 12,000, 4,000, 1,000). In order to avoid overlapping of peaks, four types of samples of 900,000, 100,000, 12,000, and 1,000 were mixed, and 3 types of samples were mixed of 150,000, 30,000, and 4,000, and these two types of samples were measured separately.

[Determination of imidization rate]

5(草野科學製))中，添加重氫化二甲基亞碸(DMSO-d6,0.05%TMS(四甲基矽烷)混合品)(0.53ml)，用超音波使其完全地溶解。藉由NMR測定機(JNW-ECA500)(日本電子datum製)，測定該溶液的500MHz的質子NMR。醯亞胺化率係如下求得：將來自於醯亞胺化前後未變化的構造的質子定為基準質子，使用該質子的波峰累積值、與在 9.5ppm~10.0ppm附近所出現的來自於醯胺酸的NH基的質子波峰累積值，並藉由以下之式可求得。 The imidization rate of polyimine in the synthesis example was measured in the following manner. Put 20 mg of polyimide powder into an NMR sample tube (NMR sampling tube stand,

5 (made by Kusano Science)), add deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53ml), and dissolve it completely with ultrasound. The 500 MHz proton NMR of the solution was measured with an NMR measuring machine (JNW-ECA500) (manufactured by JEOL Datum). The rate of imidization is determined as follows: the protons from the unchanged structure before and after imidization are set as the reference protons, and the peak cumulative value of the protons is used, and the protons appearing near 9.5 ppm to 10.0 ppm are derived from The cumulative value of the proton peak of the NH group of amide acid can be obtained by the following formula.

The imidization rate (%)=(1-α‧x/y)×100

In the above formula, x is the peak cumulative value of protons derived from the NH group of amide acid, y is the cumulative peak value of reference protons, and α-based polyamide acid (the imidation rate is 0%) when the reference proton is relative to The ratio of the number of NH protons of one amide acid.

[Production of liquid crystal cell]

A liquid crystal cell having a structure of a fringe field switching (Fringe Field Switching: referred to as FFS) mode liquid crystal display element was produced.

First, prepare a substrate with electrodes. The substrate is a glass substrate with a size of 30 mm × 50 mm and a thickness of 0.7 mm. On the substrate, there is formed an ITO electrode having a full-plate pattern that constitutes the counter electrode as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by a CVD method is formed as a second layer. 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, two types of pixels, a first pixel and a second pixel, in which comb-shaped pixel electrodes formed by patterning an ITO film are arranged as a third layer are formed. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-tooth shape formed by an arrangement of a plurality of "U"-shaped electrode elements with a curved center portion. The width in the short-side direction of each electrode element was 3 μm, and the interval between the electrode elements was 6 μm. The pixel electrode forming each pixel is composed of a plurality of "U"-shaped electrode elements with a curved center part. Therefore, the shape of each pixel is not a rectangular shape, but has the same shape as the electrode element with a curved center part. Similar to the thick "ㄑ" shape. Then, each pixel is divided up and down with the curved portion in the center as a boundary, and has a first area on the upper side of the curved portion and a second area on the lower side.

When the first area and the second area of each pixel are compared, the formation directions of the electrode elements constituting the pixel electrodes are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrode in the first area of the pixel are formed at an angle of +10° (clockwise), and the picture The electrode elements of the pixel electrodes in the second area of the pixel are formed at an angle of -10° (clockwise). That is, in the first area and the second area of each pixel, the direction of the rotation (in-plane turning) of the liquid crystal in the surface of the substrate induced by the application of the voltage between the pixel electrode and the counter electrode is Constructed in opposite directions to each other.

Next, after filtering the obtained liquid crystal alignment agent with a 1.0 μm filter, it was applied by spin coating to the prepared substrate with electrodes and the inner surface of which was formed with an ITO film with a columnar spacing of 4 μm in height. On the glass substrate. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. The surface of the coating film is irradiated with linearly polarized light with an extinction ratio of 10:1 or more through the polarizing plate and ultraviolet rays with a wavelength of 254 nm line. The substrate is immersed in at least one type of solvent selected from water and organic solvents for 5 minutes, followed by a cleaning step of immersing in pure water for 1 minute, and/or heating on a hot plate at 150°C to 300°C for 30 minutes. Minutes heating step, so that a substrate with a liquid crystal alignment film can be obtained. Using the above two substrates as a set, a sealant was printed on the substrates, and the other substrate was bonded so that the liquid crystal alignment film faces face each other and the alignment direction became 0°, and then the sealant was cured to produce a hollow Unit cell. The empty cell is injected with liquid crystal MLC-7026-100 (manufactured by Merck) by a reduced pressure injection method, and the injection port is sealed to obtain an FFS driven liquid crystal cell. After that, the obtained liquid crystal cell was heated at 110° C. for 1 hour and left overnight, and then used for various evaluations.

[Evaluation of the bright spots of the liquid crystal cell (comparison)]

After storing the above-produced liquid crystal cell in a constant temperature environment of 80° C. for 200 hours, the evaluation of the bright spot of the liquid crystal cell was performed. The evaluation of the bright spot of the liquid crystal cell was performed by observing the liquid crystal cell with a polarizing microscope (ECLIPSE E600WPOL) (manufactured by Nikon Corporation). Specifically, set the liquid crystal cell in a crossed Nicol state, observe the liquid crystal cell with a polarizing microscope with a magnification of 5 times, and calculate the number of identifiable bright spots. If the number of bright spots is less than 10, set Set to "good", and set to "bad" if it exceeds.

<Synthesis Example 1>

Synthesis of 4-[2-(4-amino-2-fluorophenyl)ethoxy]aniline (DA-6)

(step 1)

In 4-nitrofluorobenzene (141g, 1000mmol) and ethylene glycol (1220g, 20mol) in THF (tetrahydrofuran) solution (848g), add 60% sodium hydride (44.0g, 1100mmol), and at room temperature It reacts for 24 hours. After adding water (1000 g) to this solution and stirring at room temperature for 2 hours, ethyl acetate (4000 g) was added and washed with water (1500 g) three times. The obtained organic phase is dried with magnesium sulfate, and after the magnesium sulfate is removed by filtration, the crude product can be obtained by concentration. By using toluene (500 g) and ethyl acetate (400 g), the obtained crude product was recrystallized to obtain M1 as a white solid. (Yield: 48.8g, 26%)

Ethylene glycol derivatives (M1):

¹ H-NMR (DMSO, δ ppm): 8.23-8.19 (m, 2H), 7.18-7.14 (m, 2H), 5.00-4.97 (m, 1H), 4.16-4.14 (m, 2H), 3.78-3.74 (m, 2H).

(Step 2)

To M1 (23.8g, 130mmol) and 3,4-difluoronitrobenzene (24.8g, 156mmol) in DMF (dimethylformamide) solution (119g), add 60% sodium hydride (7.8g, 195mmol) ), and allowed to react at room temperature for 1 hour. This solution was poured into water (1000 g), and after stirring at room temperature for 2 hours, the crude product was recovered by filtration. By using acetonitrile (200 g), the obtained crude product was recrystallized to obtain M2 as a white solid. (Yield: 36.7g, 88%)

Dinitro compound (M2):

¹ H-NMR (DMSO, δ ppm): 8.25-8.14 (m, 4H), 7.53-7.48 (m, 1H), 7.25-7.21 (m, 2H), 4.65-4.56 (m, 4H).

(Step 3)

M2 (36.7g, 114mmol) and 5% platinum carbon (3.67g, 10wt%) were added to THF (184g), and stirred at room temperature under a hydrogen environment for 24 hours. hour. After the platinum carbon is removed by filtration of the obtained reaction liquid, it is concentrated to obtain a crude product. The obtained crude product was repulped and washed with ethyl acetate (108 g) to obtain DA-6. (Yield: 18.1g, 61%)

Diamine derivative (DA-6):

¹ H-NMR (DMSO, δ ppm): 6.86 (t, 1H), 6.70-6.66 (m, 2H), 6.53-6.49 (m, 2H), 6.43-6.38 (m, 1H), 6.31-6.28 (m , 1H), 4.96 (s, 2H), 4.63 (s, 2H), 4.14 to 4.06 (m, 4H).

<Synthesis example 2>

Synthesis of 1,2-bis(4-amino-2-methylphenoxy)ethane (DA-7)

(step 1)

Add 4-nitro-o-cresol (48.2g, 315mmol), dibromoethane (28.2g, 150mmol), potassium carbonate (49.8g, 360mmol) in DMF solution (282g), and stir at 75°C for 17 hour. The obtained reaction liquid was poured into water (1500 g), and the crude product was recovered by filtration. M3 was obtained as a white solid by reslurrying and washing the obtained crude product with methanol (80 g). (Yield: 20.7g, 42%)

Dinitro compound (M3):

¹ H-NMR (DMSO, δ ppm): 8.15 to 8.11 (m, 4H), 7.27 (d, 2H), 4.57 (s, 4H), 2.21 (s, 6H).

(Step 2)

A DMF solution of M3 (20.7 g, 62.4 mmol) and palladium (2.72 g, 10 wt%) was added, and stirred at room temperature for 2 days under a hydrogen environment. After filtering the obtained reaction liquid to remove palladium, it can be concentrated to obtain a crude product. By recrystallizing the obtained crude product using acetonitrile (60 g), DA-7 can be obtained. (Yield: 13.5g, 80%)

Diamine compound (DA-7):

¹ H-NMR (DMSO, δ ppm): 6.65-6.63 (m, 2H), 6.36-6.30 (m, 4H), 4.51 (s, 4H), 4.04 (s, 4H), 2.02 (s, 6H).

<Synthesis Example 3>

Synthesis of 4'-(2-(4-aminophenoxy)ethoxy)-[1,1'-biphenyl1-4-amine (DA-4)

Use the following two-stage approach to synthesize aromatic diamine compounds 物(DA-4).

(step 1)

Dissolve 4-hydroxy-4'-nitrobiphenyl (10.0g, 46.5mmol) in DMF (40.0g), add potassium carbonate (17.2g, 69.7mmol), and drop β-bromo-4 at 80°C -Nitrophenyl ethyl ether (17.2 g, 69.7 mmol) in DMF solution (40.0 g).

Stirring was maintained at 80°C for 2 hours, and the disappearance of the raw materials was confirmed by high-speed liquid chromatography (hereinafter referred to as HPLC). After that, the reaction liquid was cooled to room temperature, water (500.0 g) was added, the precipitate was filtered, and washed with water (100.0 g) twice. The obtained filtrate was washed twice with MeOH (500.0 g). The precipitate was filtered and dried under reduced pressure at 50°C to obtain 4-nitro-4'-(2-(4-nitrophenoxy)ethoxy)-1,1'-biphenyl ( M4) (white powder, yield: 17.6 g, yield: 99%).

¹ H NMR (DMSO-d ₆ ): δ 8.22-8.29 (m, 4H, C ₆ H ₄ ), 7.94 (d, J = 7.2 Hz, 2H, C ₆ H ₄ ), 7.79 (d, J = 8.8 Hz , 2H, C ₆ H ₄ ), 7.25-7.15 (m, 4H, C ₆ H ₄ ) 4.54-4.45 (m, 4H, CH ₂ ). ¹³ C{ ¹ H}NMR (DMSO-d ₆ ): δ 164.1, 159.6, 146.6, 146.5, 141.4, 130.7, 129.1, 127.5, 126.4, 124.5, 115.7, 115.6, 67.8, 66.7 (each s).

Melting point (DSC): 193℃

(Step 2)

Dissolve 4-nitro-4'-(2-(4-nitrophenoxy)ethoxy)-1,1'-biphenyl (M4) (5.0g, 13.1mmol) in tetrahydrofuran (100.0g) 5% palladium-carbon (0.1g) was added to it, and stirred at room temperature for 2 hours under a hydrogen environment. The disappearance of the raw material was confirmed by HPLC, and it was dissolved in tetrahydrofuran (800.0 g), the catalyst was removed by filtration, and the filtrate was concentrated. This was washed with heptane (200.0 g), and the precipitated solid was filtered and dried to obtain DA-4 (white powder, yield: 4.0 g, yield: 94%).

¹ H NMR (DMSO-d ₆ ): δ 7.45 (d, J = 8.8 Hz, 2H, C ₆ H ₄ ), 7.29 (d, J = 8.8 Hz, 2H, C ₆ H ₄ ), 6.97 (d, J =8.8Hz, 2H, C ₆ H ₄ ), 6.70(d, J =8.8Hz, 2H, C ₆ H ₄ ), 6.62(d, J =8.8Hz, 2H, C ₆ H ₄ ), 6.52(d, J = 8.8Hz, 2H, C ₆ H ₄ ), 5.14 (s, 2H, NH ₂ ), 4.64 (s, 2H, NH ₂ ), 4.24 (br, 2H, CH ₂ ), 4.16 (br, 2H, CH ₂ ). ¹³ C{ ¹ H}NMR (DMSO-d ₆ ): δ 157.2, 150.0, 148.2, 143.1, 133.9, 127.7, 126.2, 116.3, 115.9, 115.5, 115.0, 114.4, 67.2, 66.9 (each s).

Melting point (DSC): 156℃

<Synthesis Example 3>

In a 100mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh out DA-1 1.47g (6.00mmol), DA-16 0.83g (4.00mmol), DA-8 1.55g (6.00mmol), DA- 22 1.07 g (4.00 mmol), 65.98 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 4.35 g (19.4 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and 2.00 g of NMP was further added to make a solid The content concentration becomes 12% by mass, and it is stirred at room temperature for 24 hours to obtain a polyamide acid solution (PAA-1). The polyamide acid had Mn=12972, Mw=28619.

<Synthesis example 4~32>

Table 1-1 and Table 1-2 respectively indicate the use of diamine and the amount, and the use of tetracarboxylic dianhydride and the amount, except for the addition of the solid content concentration of the obtained polyamide acid solution Except for NMP, the same procedure as in Synthesis Example 3 was carried out to obtain the polyamide acids of Synthesis Examples 4 to 32.

The main points in such synthesis examples 3 to 32 are shown in the following Table 1-1 and Table 1-2. In addition, the unit showing the numerical value of the usage amount after the name of the diamine and tetracarboxylic dianhydride in Table 1-1 and Table 1-2 is "mmol".

<Synthesis Example 33>

Set a 300ml four-necked flask with a stirring device and a nitrogen introduction tube into a nitrogen environment, and add DA-2 0.78g (7.21mmol), DA-1 1.17g (4.81mmol), DA-8 1.86g (7.21mmol) 1.64 g (4.81 mmol) of DA-29, 53 mL of NMP, 145 mL of GBL, and 4.5 mL (55.97 mmol) of pyridine as a base were added and dissolved. Next, 7.58 g (23.32 mmol) of DCL-1 was added while stirring this diamine solution, and it was made to react under water cooling for 14 hours. 0.28 mL (3.46 mmol) of acrylic chloride was added to this reaction solution, and the reaction was further allowed to react for 6 hours. The obtained solution of polyamide ester was stirred while being poured into In 1200 mL of 2-propanol, filter the precipitated white precipitate. Next, the filtered white precipitate was washed 5 times with 600 mL of 2-propanol, and dried to obtain 11.89 g of white polyamide resin powder. The polyamide ester had Mn=17367 and Mw=36057.

The obtained polyamide resin powder was dissolved in 87.19 g of GBL, and a polyamide solution (PAE-1) with a solid content concentration of 12% by mass was obtained.

<Synthesis Example 34>

In a 100mL four-necked flask with a stirring device and a nitrogen introduction tube, weigh out DA-2 2.60g (24.0mmol), DA-1 5.86g (24.0mmol), DA-8 4.13g (16.0mmol) and DA- 29 5.46g (16.0mmol), then add 233.38g of NMP, and stir to dissolve it while feeding nitrogen. While stirring the diamine solution, 17.31 g (77.2 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and NMP was further added to make the solid content concentration When it becomes 12 mass %, it stirs at 40 degreeC for 4 hours, and a polyamide acid solution (PAA-31) can be obtained. The Mn of this polyamic acid solution was=13821, Mw=34465.

<Synthesis Example 35>

In a 100 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, 50 g of the obtained polyamide acid solution (PAA-31) was measured, and 25 g of NMP was added and stirred for 30 minutes. To the obtained polyamide acid solution, 4.16 g of acetic anhydride and 1.07 g of pyridine were added, and heated at 55°C for 2 hours The chemical imidization was carried out for 30 minutes. The obtained reaction liquid was poured into 300 mL of methanol while stirring, and the deposited precipitate was taken out by filtration. Next, the precipitate was washed three times with 300 mL of methanol. Next, by drying the obtained resin powder at 60° C. for 12 hours, a polyimide resin powder can be obtained. The imidization rate of this polyimide resin powder was 70%, Mn=4025 and Mw=6789.

In a 100mL Erlenmeyer flask with a stir bar, weigh 4.80g of the obtained polyimide resin powder, and then add 35.20g of NMP, stir at 70℃ for 12 hours to dissolve, the solid content concentration can be obtained as 12 Mass% polyimide solution (PI-1).

<Synthesis Example 36>

In a 50mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh out DA-2 0.39g (3.60mmol), DA-4 1.15g (3.60mmol), DA-1 0.59g (2.40mmol), DA- 27 1.34g (2.40mmol), 41.76g of NMP was added, and it was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 2.50 g (11.15 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and 2.00 g of NMP was further added to make the solid When the content concentration becomes 12% by mass, the polyamide acid solution (PAA-32) can be obtained by stirring at room temperature for 24 hours. The polyamide acid had Mn=10222 and Mw=25307.

<Synthesis Example 37>

In a 50mL four-necked flask with a stirring device and a nitrogen introduction tube, measure Take DA-1 1.47g (6.00mmol), DA-4 1.92g (6.00mmol), DA-15 0.60g (4.00mmol), DA-27 2.23g (4.00mmol), and then add 58.18g of NMP, while feeding Nitrogen was stirred while dissolving. While stirring the diamine solution, 4.21 g (18.80 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and 2.00 g of NMP was further added to make the solid When the content concentration becomes 12% by mass, the polyamide acid solution (PAA-33) can be obtained by stirring at 40°C for 24 hours. The polyamide acid had Mn=10234 and Mw=25900.

<Synthesis Example 38>

In a 500mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh out 15.9g (80mmol) of DA-25 and 6.0g (20mmol) of DA-13, and then add 230.0g of NMP, and stir while adding nitrogen. Dissolve. While stirring this diamine solution, 4.4 g (22.5 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the mixture was stirred overnight. Then, 18.8 g (75 mmol) of DAH-4 was added, and NMP was added so that the solid content concentration was 15% by weight, and the mixture was stirred at 50° C. for 10 hours to obtain a solution of polyamide acid (PAA-34). The molecular weight of this polyamic acid is Mn=18020 and Mw=45464.

<Synthesis Example 39>

In a 1000 mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh 39.89 g (200.2 mmol) of DA-25, 7.60 g (49.95 mmol) of 3,5-diaminobenzoic acid, and add 282 g of NMP to one side. Feed in nitrogen Dissolve while stirring. While stirring the diamine solution, 14.88 g (75.10 mmol) of 1,2,3,4-butanetetracarboxylic dianhydride was added, and NMP was further added so that the solid content concentration became 15% by mass. Stir at low temperature for 2 hours. Next, 283 g of NMP was added, 50.3 g (171.0 mmol) of DAH-3 was added, and NMP was added so that the solid content concentration became 12% by mass, and the mixture was stirred at room temperature for 24 hours to obtain polyamide acid (PAA -35) solution. The molecular weight of this polyamic acid is Mn=14607 and Mw=35641.

<Synthesis Example 40>

In a 500mL four-necked flask equipped with a stirring device and a nitrogen introduction tube, weigh out 17.90g (60.0mmol) of DA-13 and 6.01g (40.00mmol) of DA-15, then add 229.96g of NMP, and stir while feeding nitrogen. Let it dissolve. While stirring the diamine solution, 18.43 g (94.0 mmol) of 1,2,3,4-tetrabutanetetracarboxylic dianhydride was added, and NMP was further added so that the solid content concentration became 15% by mass, Stir at room temperature for 24 hours to obtain a solution of polyamide acid (PAA-36). The molecular weight of this polyamic acid is Mn=17183 and Mw=39542.

<Comparative Synthesis Example 1>

In a 50mL four-necked flask with a stirring device and a nitrogen introduction tube, measure DA-1 0.88g (3.60mmol), DA-2 0.65g (6.00mmol), DA-30 0.96g (2.40mmol), and then add NMP is 28.57g, and it is dissolved by stirring while feeding nitrogen gas. While stirring the two At the same time as the amine solution, 2.57g (11.46mmol) of ADA-0 was added, and 8.49g of NMP was added so that the solid content concentration became 12% by mass, and stirred at room temperature for 24 hours to obtain a polyamide acid solution ( B-1). The molecular weight of this polyamic acid is Mn=16530 and Mw=37220.

<Comparative Synthesis Examples 2~4>

Table 2 shows the use of diamine and the amount, and the tetracarboxylic dianhydride and the amount, and in addition to the addition of NMP for the solid content concentration of the obtained polyamide acid solution, and the comparative synthesis example 1 The same implementation can obtain the polyamide acids B2 to B4 of Comparative Synthesis Examples 1 to 4.

The main points in the above-mentioned comparative synthesis examples 1 to 4 are shown in Table 2 below. In addition, the unit showing the numerical value of the used amount after the name of the diamine and the name of tetracarboxylic dianhydride in Table 2 is "mmol".

<Example 1>

In a 50 mL Erlenmeyer flask with a stir bar, weigh 12.50 g of the polyamide acid solution (PAA-1) obtained in Synthesis Example 3, and then add 1.0% by mass of 3-glycidoxypropylmethyldiethoxy NMP solution of base silane 1.8g, 9.70g of NMP, 6.00g of BCS, stirred with a magnetic stirrer for 30 minutes to obtain the liquid crystal alignment agent (AL-1).

<Examples 2~38>

In Table 3-1 and Table 3-2, except for the use of the polyamide acid solution and the amount, and the solvent and the amount, respectively, the same implementation as in Example 1 can obtain liquid crystal alignment agents AL-2~AL-38 . The main points in the above Examples 1 to 38 are shown in the following Table 3-1 and Table 3-2. Note that the units of the values in parentheses in Table 3 and Table 3-2 are all grams (g).

<Comparative Example 1>

In a 50 mL Erlenmeyer flask with a stir bar, weigh 12.50 g of the polyimide solution (B-1) obtained in Comparative Synthesis Example 1, and then add 1.0% by mass of 3-glycidoxypropylmethyldiethyl 1.50 g of NMP solution of oxysilane, 10.00 g of NMP, 6.00 g of BCS, and stirring with a magnetic stirrer for 30 minutes can obtain the liquid crystal alignment agent (AL-1b).

<Comparative Examples 2~6>

In Table 4, except that the polyamide acid solutions B-1 to B-4, PAA-35, and PAA-36 are used in the same amount, and the solvent and the amount are used, the comparison can be obtained in the same manner as in Comparative Example 1. Examples 2 to 6 of the liquid crystal alignment agent AL-1b~AL-6b. Still, in Comparative Example 6, 0.75 g of the crosslinking agent AD-I was added to the liquid crystal alignment agent.

Table 4 shows the main points of the above-mentioned Comparative Examples 1 to 6. Note that the units of the values in parentheses in Table 4 are all grams (g).

<Example 39>

After filtering the liquid crystal alignment agent (AL-1) obtained in Example 1 with a 1.0 μm filter, it was applied to the prepared substrate with electrodes and the inner surface of the substrate with ITO film formed by spin coating. On a glass substrate with a column spacer with a height of 4 μm. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. ^{The coating film surface was irradiated with ultraviolet rays of 150 mJ/cm 2} having a wavelength of 254 nm and a linearly polarized light having an extinction ratio of 26:1 through a polarizing plate. The substrate was immersed in a mixed solvent of 2-propanol/water = 1/1 (mass ratio) at 25°C for 5 minutes, then immersed in pure water at 25°C for 1 minute, and heated on a hot plate at 230°C. After drying for 30 minutes, a substrate with a liquid crystal alignment film can be obtained. Using the above two substrates as a set, a sealant was printed on the substrates, and the other substrate was bonded so that the liquid crystal alignment film faces face each other and the alignment direction became 0°, and then the sealant was cured to produce a hollow Unit cell. This empty cell is injected with liquid crystal MLC-7026-100 (manufactured by Merck) by a reduced pressure injection method, and the injection port is sealed to obtain an FFS driven liquid crystal cell. After that, the obtained liquid crystal cell was heated at 110°C for 1 hour and left overnight. After placing the obtained liquid crystal cell in a hot-air circulating oven at 80° C. for 200 hours, observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Example 40>

After filtering the liquid crystal alignment agent (AL-2) obtained in Example 2 with a 1.0 μm filter, it was applied to the prepared substrate with electrodes and the inner surface of the substrate with ITO film formed by spin coating. On a glass substrate with a column spacer with a height of 4 μm. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. ^{After irradiating the coating film surface with 200 mJ/cm 2} of ultraviolet rays having a wavelength of 254 nm with an extinction ratio of 26:1 to the coating film surface through a polarizing plate, it was heated on a hot plate at 230°C for 30 minutes. The substrate was immersed in a mixed solvent of 2-propanol/water = 1/1 (mass ratio) at 25°C for 5 minutes, then immersed in pure water at 25°C for 1 minute, and heated on a hot plate at 80°C. After drying for 10 minutes, a substrate with a liquid crystal alignment film can be obtained.

Using the obtained substrate with a liquid crystal alignment film, an FFS driven liquid crystal cell was produced in the same manner as described in Example 39. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, when the bright spots in the liquid crystal cell were observed, the number of bright spots was less than 10, which was good.

<Examples 41~44>

Table 5 shows that in addition to the use of liquid crystal alignment agents AL-3~AL-6, In addition, the FFS driving cell was fabricated in exactly the same way as in Example 39, and the bright spot was observed. The results are shown in Table 5, respectively.

<Example 45>

After filtering the liquid crystal alignment agent (AL-7) obtained in Example 7 with a 1.0 μm filter, it was applied to the prepared substrate with electrodes and the inner surface of the substrate with ITO film formed by spin coating. On a glass substrate with a column spacer with a height of 4 μm. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. Mediated via a polarizing plate is irradiated to the coated surface extinction ratio 26: ^2, 1 is heated linearly polarized ultraviolet wavelength of 254nm 150mJ / cm at 230 deg.] C hot plate for 30 minutes, to obtain a liquid crystal alignment film with Substrate.

Using the obtained substrate with a liquid crystal alignment film, an FFS driven liquid crystal cell was produced in the same manner as described in Example 39. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Example 46>

Except that the liquid crystal alignment agent (AL-8) obtained in Example 8 was used, the FFS driving cell was produced in the same manner as in Example 45. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Example 47>

Except that the liquid crystal alignment agent (AL-9) obtained in Example 9 was used, the FFS driving cell was produced in the same manner as in Example 40. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Example 48>

Except that the liquid crystal alignment agent (AL-10) obtained in Example 10 was used, and the linearly polarized light with an extinction ratio of 26:1 was irradiated with 250 mJ/cm ² of ultraviolet light with a wavelength of 254 nm through a polarizing plate, the same as in Example 40 The same method is used to fabricate the FFS drive unit cell. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Example 49>

After filtering the liquid crystal alignment agent (AL-11) obtained in Example 11 with a 1.0 μm filter, it was applied to the prepared substrate with electrodes and the inner surface of the substrate with ITO film formed by spin coating. On a glass substrate with a column spacer with a height of 4 μm. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. ^{The coating film surface was irradiated with ultraviolet rays of 150 mJ/cm 2 with} a wavelength of 254 nm and a linearly polarized light with an extinction ratio of 26:1 through a polarizing plate. The substrate was immersed in 1-methoxy-2-propanol at 25°C for 5 minutes, then immersed in pure water at 25°C for 1 minute, and then heated on a hot plate at 230°C for 30 minutes. The substrate of the liquid crystal alignment film. Using the obtained substrate with a liquid crystal alignment film, an FFS driven liquid crystal cell was produced in the same manner as described in Example 39. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Examples 50~54>

Table 6 shows that the liquid crystal alignment agents AL-12 to AL-16 were used, respectively, and the FFS driving cell was fabricated in the same method as in Example 39 or 49 shown in Table 6, and the bright spots were observed. The results are shown in Table 6, respectively.

<Example 55>

After filtering the liquid crystal alignment agent (AL-17) obtained in Example 17 with a 1.0 μm filter, it was applied to the prepared substrate with electrodes and the inner surface of the substrate with ITO film formed by spin coating. On a glass substrate with a column spacer with a height of 4 μm. After drying on a hot plate at 80°C for 5 minutes, it was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a film thickness of 100 nm. ^{The coating film surface was irradiated with ultraviolet rays of 150 mJ/cm 2 with} a wavelength of 254 nm and a linearly polarized light with an extinction ratio of 26:1 through a polarizing plate. The substrate was immersed in ethyl lactate at 25°C for 5 minutes, and then immersed in pure water at 25°C for 1 minute, and then heated on a hot plate at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film. Using the obtained substrate with a liquid crystal alignment film, an FFS driven liquid crystal cell was produced in the same manner as described in Example 39. After the obtained liquid crystal cell was placed in a hot-air circulating oven at 80°C for 200 hours, the results of observation of bright spots in the liquid crystal cell showed that the number of bright spots was less than 10, which was good.

<Examples 56~76>

Table 7 shows that the liquid crystal alignment agents AL-18~AL-38 were used respectively, and the FFS driving unit cell was made by the same method as in Example 39, 40, 45, 49 or 55 shown in Table 6, and the bright spot was observed. . In Example 58, although it was the unit cell of Example 39, the linearly polarized light with an extinction ratio of 26:1 was irradiated with 700 mJ/cm ² of ultraviolet rays having a wavelength of 254 nm through a polarizing plate.

The results of the foregoing Examples 56 to 76 are shown in Table 7, respectively.

<Comparative Examples 5-10>

Table 7 shows that the liquid crystal alignment agents AL-1b to AL-6b were used to fabricate FFS driving cells in the same manner as in Example 40 or 45 shown in Table 7, and the bright spots were observed. The results are shown in Table 8, respectively.

In Comparative Examples 6 and 7, although the unit cell of Example 40 was used, the linearly polarized light with an extinction ratio of 26:1 was irradiated with 150 mJ/cm ² of ultraviolet light having a wavelength of 254 nm through a polarizing plate. In addition, in Comparative Example 8, although it was the unit cell of Example 40, the linearly polarized light with an extinction ratio of 26:1 was irradiated with ultraviolet rays of 100 mJ/cm ² at a wavelength of 254 nm with an extinction ratio of 26:1 through a polarizing plate.

The results of the above-mentioned Comparative Examples 5 to 10 are shown in Table 8, respectively.

[Industrial Utilization]

With the liquid crystal alignment agent of the present invention, even when a negative type liquid crystal is used, bright spots will not be generated (it is caused by the decomposition products of the liquid crystal alignment film produced during the photo-alignment process), and a good residual image can be obtained. Characteristic liquid crystal alignment film. Therefore, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention has few bright spots as a factor of contrast reduction, and can reduce the residual image caused by AC driving in the liquid crystal display element of the IPS driving mode or the FFS driving mode. , It is possible to obtain a liquid crystal display element of an IPS driving method or an FFS driving method with excellent residual image characteristics. Therefore, it can be used in liquid crystal display elements that require high display quality.

Still, the entire contents of the specification, patent application scope, and abstract of Japanese Patent Application No. 2015-199682 filed on October 7, 2015 and Japanese Patent Application No. 2016-026278 filed on February 15, 2016 are quoted here. It is cited as the disclosure of the specification of the present invention.

Claims (13)

A liquid crystal alignment agent for a photo-alignment method, which contains at least one polymer selected from the group consisting of polyimide precursors and polyimides of the polyimide precursors. The polyimide precursor is obtained from a diamine component containing four or more types of diamines and a tetracarboxylic acid derivative, wherein at least one of the four or more types of diamines contains the following formula (7) The diamine of the structure indicated,

(In formula (7), D is t-butoxycarbonyl). The liquid crystal alignment agent for the photo-alignment method of claim 1, wherein at least one of the four or more types of diamines is at least one selected from the following formulas (5) and (6),

(In formulas (5) and (6), A ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group with 2 to 20 carbon _{atoms, and A 2} is a hydrogen atom, a halogen atom, Hydroxyl group, amine group, thiol group, nitro group, phosphoric acid group, or a monovalent organic group with 1 to 20 carbons, a is an integer of 1 to 4, when a is 2 or more, _{the structure of A 1} can be the same Or different, b and c are each independently an integer of 1~2). According to claim 1, the liquid crystal alignment agent for the photo-alignment method, wherein the aforementioned tetracarboxylic acid derivative is a tetracarboxylic acid derivative having photoreactivity. According to claim 3, the liquid crystal alignment agent for the photo-alignment method, wherein the aforementioned tetracarboxylic acid derivative is a tetracarboxylic acid derivative having photoreactivity and an alicyclic structure. The liquid crystal alignment agent for photo-alignment method according to claim 4, wherein the aforementioned tetracarboxylic acid derivative is a tetracarboxylic dianhydride represented by the following formula (3),

(X ₁ is selected from at least 1 type from the group of structures represented by the following formulas (X1-1)~(X1-10))

(In formulas (X1-1) ~ (X1-4), R ₃ ~ R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbons, an alkenyl group with 2 to 6 carbons, and a carbon number of 2 ~6 alkynyl group, fluorine atom-containing monovalent organic group with carbon number of 1 to 6, or phenyl group). The liquid crystal alignment agent for the photo-alignment method of claim 5, wherein, in the above formula (3), _{the structure of X 1} is the above formula (X1-1). The liquid crystal alignment agent for photo-alignment method according to claim 5, wherein, in the above formula (3), _{the structure of X 1} is selected from at least 1 of the structures represented by the following formulas (X1-11)~(X1-16) Species,

Such as claim 7 of the liquid crystal alignment agent for the photo-alignment method, wherein, in the above formula (3), _{the structure of X 1} is represented by the following formula (X1-11) or (X1-12),

According to claim 1 or 2, the liquid crystal alignment agent for the photo-alignment method, wherein the content of each diamine constituting the above-mentioned four or more types of diamines is 1-30 mol% with respect to the total diamine component. For example, the liquid crystal alignment agent for photo-alignment method of claim 1 or 2, wherein the type of diamine is 4 or more and 10 or less. A liquid crystal alignment film for photo-alignment method, which is obtained from the photo-alignment method liquid crystal alignment agent of any one of claims 1 to 10. A liquid crystal display element comprising the liquid crystal alignment film for the optical alignment method of claim 11. The liquid crystal display element of claim 12, wherein a negative type liquid crystal is provided as the liquid crystal.