TW201840644A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal alignment agent containing at least one polymer selected from among polyimide precursors and polyimides that are imidized products thereof obtained from: a tetracarboxylic acid derivative component containing at least one substance selected from among a tetracarboxylic acid dianhydride represented by formula (1) and derivatives thereof and at least one substance selected from among a tetracarboxylic acid dianhydride represented by formula (2) and derivatives thereof; and a diamine component containing at least one diamine selected from between formulas (3) and (4).

Description

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

The invention relates to a liquid crystal alignment agent for manufacturing a liquid crystal display element, 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, and the like are usually provided with a liquid crystal alignment film for controlling the alignment state of the liquid crystal in the element. At present, the most popular liquid crystal alignment film in the industry will be formed on the surface of the electrode substrate, and the surface of the film formed of polyimide and / or polyimide of this polyimide It is produced by rubbing cloth such as cotton, nylon, polyester, etc. in one direction and performing a so-called rubbing treatment.

The friction treatment of the film surface during the alignment process of the liquid crystal alignment film is simple and excellent in productivity, and can be used in industrial methods. However, the requirements for high-performance, high-definition, and large-sized liquid crystal display elements are increasing. The surface of the alignment film caused by friction treatment is injured, dust is generated, the influence caused by mechanical force or static electricity, and the alignment treatment surface. Various problems such as internal unevenness are obvious. Instead of the rubbing-treated liquid crystal alignment treatment method, a light alignment method that imparts alignment energy to a liquid crystal by irradiating polarized radiation is known. According to the liquid crystal alignment treatment by the photo-alignment method, it is proposed to use a photoisomerization reaction, a photocrosslinking reaction, a photodecomposition reaction, and the like (see Non-Patent Document 1).

Further, Patent Document 1 proposes to use a polyfluorene imide film having an alicyclic structure such as a cyclobutane ring in the main chain for a photo-alignment method. As in the photo-alignment method described above, an industrially simple manufacturing process can impart liquid crystal alignment energy. Not only that, in a liquid crystal display element in an IPS driving method or a fringe field switching (hereinafter referred to as Fringe Field Switching: FFS) driving method, a liquid crystal alignment film provided with liquid crystal alignment energy by a photo-alignment method is compared with a liquid crystal alignment film provided by a rubbing process. Liquid crystal alignment films capable of liquid crystal alignment can be expected to improve the contrast or viewing angle characteristics of liquid crystal display elements. In this way, as the above-mentioned light alignment method can improve the performance of a liquid crystal display element, it can be attracted attention as a promising liquid crystal alignment processing method. In addition to the basic characteristics such as excellent liquid crystal alignment and electrical characteristics, the liquid crystal alignment film used in the liquid crystal display element of the IPS driving method or the FFS driving method must also be prevented from occurring in the liquid crystal display element due to the IPS driving method or the FFS driving method. The afterimage caused by long-term AC drive. [Prior Art Literature] [Patent Literature]

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

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

[Problems to be Solved by the Invention]

An object of the present invention is to provide a liquid crystal alignment agent capable of suppressing an afterimage caused by a long-term AC drive occurring in a liquid crystal display element of an IPS driving method or an FFS driving method, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a method having the same. Liquid crystal display element of liquid crystal alignment film. [Means to solve the problem]

In order to achieve the above-mentioned object, the present inventors have conducted careful examinations and found that by using a polycarboxylic acid obtained from a tetracarboxylic acid derivative component containing a tetracarboxylic acid derivative having a specific structure and a diamine component having a specific structure An amine or a liquid crystal alignment agent containing a polyimide precursor can achieve the above purpose. Thus, the technical features of the present invention are as follows.

1. A liquid crystal alignment agent, characterized by containing: 选自 selected from the group consisting of: at least one type selected from the group consisting of a tetracarboxylic dianhydride and a derivative thereof selected from the following formula (1), and selected from the following formula (2): Tetracarboxylic dianhydride and its derivative of at least one kind of tetracarboxylic acid derivative component; and a diamine component containing at least one kind of diamine selected from the following formulae (3) and (4); A polymer of at least one of a polyimide precursor and a polyimide of a polyimide,

In the formula, X ₁ is a structure selected from the following formulae (X1-1) to (X1-4), and X ₂ is a structure selected from the following formulas (X2-1) to (X2-2).

In the formula, R ₃ to R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, and a carbon number containing a fluorine atom. 1 to 6 monovalent organic groups or phenyl groups may be the same or different, but at least one is other than a hydrogen atom, and R ₇ to R ₂₃ are each independently a hydrogen atom, a halogen atom, and an alkane having 1 to 6 carbon atoms Radicals, alkenyl radicals having 2 to 6 carbon atoms, alkynyl radicals having 2 to 6 carbon atoms, monovalent organic radicals having 1 to 6 carbon atoms containing fluorine atoms, or phenyl groups may be the same or different,

In the formula, A ₁ is a single bond, an ester bond, a amine bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms, and A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amine group, a thiol group, or a nitrate. Group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms, where a is an integer of 1 to 4, and when a is 2 or more, the structures of A ₁ may be the same or different. b and c are each independently an integer of 1 to 2.

2. The liquid crystal alignment agent according to 1., wherein the ratio of the tetracarboxylic dianhydride or its derivative represented by the aforementioned formula (2) is 1 to 30 mol% relative to 1 mole of the all-tetracarboxylic acid derivative component. .

3. The liquid crystal alignment agent according to 1. or 2., wherein the structure of X ₁ is at least one selected from the following formulae (X1-12) to (X1-16),

.

4. The liquid crystal alignment agent according to any one of 1. to 3., wherein the structure of X ₁ is the aforementioned formula (X1-12).

5. The liquid crystal alignment agent according to any one of 1. to 4., wherein the structure of X ₂ is represented by the aforementioned formula (X2-1).

6. The liquid crystal alignment agent according to any one of 1. to 5., wherein the diamine component contains at least one selected from the following formulae (DA-1) to (DA-20),

.

7. A liquid crystal alignment film obtained from a liquid crystal alignment agent according to any one of 1. to 6.

8. A liquid crystal display element comprising a liquid crystal alignment film such as 7.

9. The liquid crystal display device according to 8., wherein the liquid crystal display device is a device that drives a liquid crystal with a transverse electric field. [Inventive effect]

In the liquid crystal alignment agent according to the present invention, in addition to excellent basic characteristics such as liquid crystal alignment and electrical characteristics, it is possible to suppress residuals caused by long-term AC driving occurring in a liquid crystal display element of an IPS driving method or an FFS driving method. Shadowed liquid crystal alignment film.

In addition, in the liquid crystal alignment film and the liquid crystal display element according to the present invention, in addition to excellent basic characteristics such as liquid crystal alignment and electrical characteristics, it is also possible to suppress long-term AC driving in a liquid crystal display element caused by an IPS drive method or an FFS drive method Afterimages caused. [Form of Implementing Invention]

The liquid crystal alignment agent of the present invention contains a polymer (hereinafter also referred to as a specific polymer) of at least one kind selected from the polyfluorene imine precursor and the polyimide of the fluorimidate. Hereinafter, each component which comprises the raw material of a specific polymer is explained in full detail.

<Tetracarboxylic acid derivative component> 不仅 The tetracarboxylic acid derivative component contained in the liquid crystal alignment agent of the present invention and used for the polymerization of a specific polymer is not only a tetracarboxylic dianhydride but also a tetracarboxylic acid derivative thereof. A tetracarboxylic acid, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, or a tetracarboxylic acid dialkyl ester dihalide compound. A tetracarboxylic dianhydride or a derivative thereof used for polymerization of a specific polymer contains at least one kind selected from the tetracarboxylic dianhydride or a derivative thereof represented by the following formula (1) and is selected from the following formula ( 2) At least one type of tetracarboxylic acid or derivative thereof.

In the formula, X ₁ is a structure selected from the following formulae (X1-1) to (X1-4).

In the formula, R ₃ to R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, and a carbon number containing a fluorine atom. 1 to 6 monovalent organic groups or phenyl groups may be the same or different, but at least one is other than a hydrogen atom. R ₇ to R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, and a carbon number 1 to 6 containing a fluorine atom The monovalent organic group or phenyl group may be the same or different.

From the viewpoint of suppressing the afterimage caused by long-term AC drive, the structure of X ₁ is preferably at least one selected from the structures represented by the following formulae (X1-12) to (X1-16), and particularly preferred is The following formula (X1-12).

The ratio of the tetracarboxylic dianhydride or its derivative represented by the above formula (1) is 1 mol, preferably 50 mol% or more, and 70 mol% or more of the tetracarboxylic dianhydride or its derivative. More preferably, it is more preferably 80 mol% or more.

X _{2 has} a structure selected from the following formulae (X2-1) to (X2-2).

In the above formula (2), X ₂ is preferably a structure represented by the following formula (X2-1) from the viewpoint of suppressing afterimages and the like caused by long-term AC drive. The ratio of the tetracarboxylic dianhydride or its derivative represented by the above formula (2) is 1 mole to 1 to 30 mole of the tetracarboxylic dianhydride or its derivative (pertetracarboxylic acid derivative component). % Is better, more preferably 10 to 30%, and still more preferably 10 to 20%.

The tetracarboxylic dianhydride and its derivative used in the polymerization of a specific polymer can be used in addition to the above formulas (1) and (2), and the tetracarboxylic dianhydride and its derivative represented by the following formula (6) Thing.

In the formula, X ₃ is a tetravalent organic group, and its structure is not particularly limited. Specific examples include structures of the following formulae (X-9) to (X-47). From the viewpoint of the ease of obtaining compounds, the structure of X ₃ is based on X-17, X-25, X-26, X-27, X-28, X-32, X-35, X-37, X- 39, X-43, X-44, X-45, X-46, and X-47 are preferred. In addition, from the viewpoint of obtaining a liquid crystal alignment film that can quickly reduce the residual charge accumulated by the DC voltage, it is preferable to use a tetracarboxylic dianhydride having an aromatic ring structure, and the structure of X ₃ is more preferably X-26, X-27, X-28, X-32, X-35, and X-37.

<Diamine component> The diamine component contained in the liquid crystal alignment agent of the present invention and used for the polymerization of a specific polymer contains at least one selected from the following formula (3) and the following formula (4).

In the formula, A ₁ is a single bond, an ester bond, a amine bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms, and A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amine group, a thiol group, or a nitrate. Group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms, where a is an integer of 1 to 4, and when a is 2 or more, the structures of A ₁ may be the same or different. b and c are each independently an integer of 1 to 2.

From the viewpoint of suppressing afterimages and the like caused by long-term AC drive, the specific structures of the above-mentioned formulas (3) and (4) are preferably structures of the following formulae (DA-1) to (DA-20). Among these, DA-1, DA-2, DA-4, DA-5, and DA-7 are more preferable.

The content of the diamine represented by the above formula (3) and the above formula (4) is preferably 50 to 100 mole%, more preferably 70 to 100 mole%, relative to 1 mole of the total diamine component. . The diamine used for the polymerization of a specific polymer may include a diamine represented by the following formula (7) in addition to the formulas (3) and (4).

In the formula, each of A _{3 is} independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms, which may be the same or different. From the viewpoint of liquid crystal alignment, A ₃ is preferably a hydrogen atom or a methyl group. Y ₁ is a divalent organic group, and specific structures thereof are exemplified by the following formulae (Y-1) to (Y-49) and (Y-57) to (Y-168).

From the viewpoint of improving the solubility of the polymer, it is preferable that the structure represented by the following formula (8) be included in the structure of Y ₁ .

In the formula, D is t-butoxycarbonyl.

Specific examples of Y ₁ including the structure of the formula (8) include Y-158, Y-159, Y-160, Y-161, Y-162, and Y-163.

<The manufacturing method of a polyamidate> The polyamidate of the polyamidate precursor used by this invention can be synthesize | combined using any one of the following (1)-(3).

(1) Case of synthesis from polyfluorinated polyfluorene The polyfluorinated polyamic acid ester can be synthesized by esterifying a polyfluorinated acid obtained from a tetracarboxylic dianhydride and a diamine. Specifically, the polyamic acid and the esterifying agent can be reacted in the presence of an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C, for 30 minutes to 24 hours, preferably 1 ~ 4 hours to synthesize.

The esterifying agent is preferably one which can be easily removed by purification, and examples thereof include N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide di neopentylbutyl acetal, N, N-dimethylformamide di-t-butyl acetal Aldehyde, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, 4- ( 4,6-dimethoxy-1,3,5-triazinefluoren-2-yl) -4-methyl morpholine chloride and the like. The addition amount of the esterifying agent is 2 to 6 mol equivalents, more preferably 2 to 4 mol equivalents, relative to the repeating unit of polyamic acid.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. in terms of the solubility of the polymer. Or mix two or more types. The concentration of the polymer in the organic solvent during the synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that the polymer is less likely to precipitate and a high molecular weight body can be easily obtained.

(2) When synthesized by the reaction of tetracarboxylic acid diester dichloride and diamine Polyfluorene esters can be synthesized from tetracarboxylic acid diester dichloride and diamine. Specifically, the tetracarboxylic acid diester dichloride and diamine can be reacted in the presence of a base and an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C, for 30 minutes to 24 minutes. Hours, preferably 1 to 4 hours for synthesis.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but in order to make the reaction proceed mildly, pyridine is preferred. The amount of the alkali added is, from the viewpoint of being easily removed, and a high-molecular-weight body can be obtained. It is preferably 2 to 4 times moles, more preferably 2 to 3 times moles, relative to the tetracarboxylic acid diester dichloride. . The organic solvent used in the above reaction is preferably N-methyl-2-pyrrolidone, γ-butyrolactone, etc. in terms of the solubility of the monomers and polymers. These solvents can be used singly or in combination of two or more.

The concentration of the polymer in the organic solvent during synthesis is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass from the viewpoint that the polymer is less likely to precipitate and a high molecular weight body can be easily obtained. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the organic solvent used for the synthesis of the polyphosphoric acid ester is preferably dehydrated as much as possible. The reaction is performed in a nitrogen environment, and the prevention of outside air mixing is good.

(3) In the case of synthesizing polyamidic acid from a tetracarboxylic acid diester and a diamine A polyphosphonium acid ester can be synthesized by polycondensing a tetracarboxylic acid diester and a diamine. Specifically, a tetracarboxylic acid diester and a diamine can be reacted in the presence of a condensing agent, a base, and an organic solvent at a temperature of 0 to 150 ° C, preferably 0 to 100 ° C, for 30 minutes to 24 minutes. Hours, preferably 3 to 15 hours.

As the condensing agent, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N can be used. '-Carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholine, O- (benzotriazol-1-yl) -N, N, N', N'-tetramethyl Thiourea tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethylmethylurea hexafluorophosphate, (2,3-dihydro- 2-thiooxy-3-benzoxazolyl) diphenylphosphonate and the like. The addition amount of the condensing agent is preferably 2 to 3 times the mole, more preferably 2 to 2.5 times the mole relative to the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the alkali is preferably from 2 to 4 times moles, and more preferably from 2 to 3 times moles, relative to the diamine component, from the viewpoint of easily removing the amount and obtaining a high molecular weight body. Examples of the organic solvent include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, and the like. In the above reaction, the reaction can be performed efficiently by adding a Lewis acid as an additive. The Lewis acid is preferably a lithium halide such as lithium chloride or lithium bromide. The addition amount of the Lewis acid is preferably 0 to 1.0 times mole, more preferably 2.0 to 3.0 times mole, relative to the diamine component.

Among the above-mentioned three synthetic methods of polyamidate, polyamidates having a high molecular weight can be obtained. Therefore, the synthetic method of (1) or (2) above is particularly preferred. The polymer solution obtained as described above can be precipitated by pouring the polymer into a weak solvent with sufficient stirring. After carrying out precipitation several times, washing with a weak solvent, and drying at room temperature or heating, a purified polyamidate powder can be obtained. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, and the like, and water, methanol, ethanol, and 2-propanol are preferred.

<Manufacturing method of polyamidic acid> The polyamidic acid of the polyamido precursor used in the present invention can be synthesized by the following method. Specifically, by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent at a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, a reaction of 30 minutes to 24 hours is preferred. It takes 1 to 12 hours to synthesize.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. in terms of the solubility of the monomers and polymers. These can be used singly or in combination of two or more kinds. The concentration of the polymer is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass, from the viewpoint that the precipitation of the polymer is unlikely to occur and a polymer is easily obtained.

The polyamic acid obtained as described above can be precipitated and recovered by pouring a polymer into a weak solvent while sufficiently stirring the reaction solution. In addition, after performing precipitation several times, washing with a weak solvent, and drying at room temperature or heating, a purified polyamic acid powder can be obtained. The weak solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, and the like, and water, methanol, ethanol, and 2-propanol are preferable.

<Production method of polyimide> The polyimide used in the present invention can be produced by subjecting the aforementioned polyamidate or polyamic acid to imidization. When producing a polyimide from a polyamic acid ester, an alkaline catalyst is added to a polyamic acid solution obtained by dissolving the polyamic acid solution or the polyamic acid resin powder in an organic solvent. Chemical imidization is simpler. Chemical fluorene imidization is preferably carried out at a relatively low temperature. In the process of fluorene imidization, it is not easy to reduce the molecular weight of the polymer, so it is preferred.

Chemical ammonium imidization is carried out by stirring a polyimide ester to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent, a solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature at which the amidine imidization reaction is performed is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C, and the reaction time is performed from 1 to 100 hours. The amount of the alkaline catalyst is 0.5 to 30 times the mole of the sulfonate group, preferably 2 to 20 times the mole. The fluorenimidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

When a polyfluorene imide is produced from a polyfluorinated acid, it is relatively simple to add a chemical fluorinated imine to the solution of the polyfluorinated acid obtained by reacting a diamine component with a tetracarboxylic dianhydride. Chemical fluorene imidization is preferably carried out at a relatively low temperature. In the process of fluorene imidization, it is not easy to reduce the molecular weight of the polymer, so it is preferred.

Chemical amidine imidization is performed by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferred because it has a moderate basicity for the reaction to proceed. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among them, when acetic anhydride is used, purification after the reaction is facilitated, so it is preferable.

The temperature of the amidine 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 times moles of the amino acid group, preferably 2 to 20 times moles, and the amount of the acid anhydride is 1 to 50 times moles of the amino acid group, preferably 3 to 30 times Mor. The fluorenimidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. In the solution after the polyimide or polyamidophosphonium imidization reaction, the added catalyst and the like remain. Therefore, the obtained polyimide polymer is recovered by the following means, and organic compounds are used. The solvent is re-dissolved, and it is preferable as the liquid crystal alignment agent of the present invention.

The solution of the polyimide obtained as described above can be precipitated into a polymer by being poured into a weak solvent while being sufficiently stirred. After several precipitations, washing with a weak solvent, and drying at room temperature or heating, a purified polymer powder can be obtained. The weak solvent is not particularly limited, and examples thereof include methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene. Examples are methanol, ethanol, 2-propanol, and acetone.

<Liquid crystal alignment agent> The liquid crystal alignment agent used in the present invention has a solution form in which a polymer component is dissolved in an organic solvent. The molecular weight of the polymer is preferably 2,000 to 500,000 based on the weight average molecular weight, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000. The number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

The concentration of the polymer of the liquid crystal alignment agent used in the present invention can be appropriately changed by setting the thickness of the coating film to be formed, but from the viewpoint of forming a uniform and defect-free coating film, it is 1% by weight. The above is preferable, and from the viewpoint of storage stability of the solution, it is preferably 10% by weight or less. The concentration of the particularly good polymer is 2 to 8% by mass.

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

The liquid crystal alignment agent of the present invention may contain, in addition to the organic solvent for dissolving the polymer component, a solvent for improving the uniformity of the coating film when the liquid crystal alignment agent is applied to a substrate. As the solvent, a solvent having a surface tension lower than that of the above-mentioned organic solvent is generally used. Specific examples include ethyl cellosolve, butyl cellosolve, ethylcarbitol, butylcarbitol, ethylcarbitol acetate, ethylene glycol, and 1-methoxy-2-propanol. , 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1- Monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate Esters, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and the like. These solvents may be used in combination of two or more.

In the liquid crystal alignment agent of the present invention, in addition to the above, a polymer other than a specific polymer may be added, a dielectric or conductive substance for the purpose of changing the electrical characteristics such as the dielectric constant or conductivity of the liquid crystal alignment film, and improving the liquid crystal. A silane coupling agent for the purpose of adhesion between the alignment film and the substrate, a crosslinkable compound for the purpose of improving the hardness or density of the film when used as a liquid crystal alignment film, and a polyamic acid in order to efficiently perform the baking of the coating film The purpose of hydrazone imidization is hydrazone promoter.

<Liquid Crystal Alignment Film / Liquid Crystal Display Element> Liquid crystal alignment film is a film obtained by applying the liquid crystal alignment agent to a substrate, and drying and firing the substrate. The substrate to which the liquid crystal alignment agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency. A glass substrate, a silicon nitride substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can also be used. . In this case, when a substrate on which an ITO electrode for driving liquid crystal is formed is used, it is preferable from the viewpoint of simplifying the manufacturing process. In addition, if the reflective liquid crystal display element is only a single-sided substrate, an opaque material such as a silicon wafer may be used. In this case, an electrode such as aluminum that reflects light may be used.

The coating method of the liquid crystal alignment agent is not particularly limited, but the coating method by screen printing, lithography, letterpress printing, or inkjet is generally used in the industry. Other coating methods include a dipping method, a roll coating method, a slit coating method, a spinner method, or a spray method, and these may be used depending on the purpose.

After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating means such as a hot plate, a thermal cycle oven, or an IR (infrared) oven to serve as a liquid crystal alignment film. The steps of drying and firing after applying the liquid crystal alignment agent of the present invention can be selected at any temperature and time. In general, in order to sufficiently remove the contained solvent, conditions such as firing at 50 to 120 ° C for 1 to 10 minutes, and then firing at 150 to 300 ° C for 5 to 120 minutes are mentioned. If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, it is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

The method for subjecting the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention to alignment treatment is preferably a photo alignment method. A preferred example of the photo-alignment method is to irradiate the surface of the aforementioned liquid crystal alignment film with radiation polarized in a certain direction. Sometimes, it is preferable to perform heat treatment at a temperature of 150 to 250 ° C to impart liquid crystal alignment (also called liquid crystal Alignment energy) method. The radiation may use ultraviolet rays or visible rays having a wavelength of 100 to 800 nm. Among them, ultraviolet rays having a wavelength of 100 to 400 nm, and more preferably 200 to 400 nm are preferable.

In order to improve the alignment of the liquid crystal, the substrate on which the liquid crystal alignment film coating film is formed may be irradiated with radiation while being heated at 50 to 250 ° C. The radiation dose is preferably 1 to 10,000 mJ / cm ² . Among them, 100 to 5,000 mJ / cm ² is more preferable. The liquid crystal alignment film produced in this way can stabilize the alignment of liquid crystal molecules in a certain direction. The higher the extinction ratio of polarized ultraviolet rays, the better the anisotropy can be imparted. Specifically, the extinction ratio of the linearly polarized ultraviolet rays is preferably 10: 1 or more, and more preferably 20: 1 or more.

In addition, in the aforementioned method, the liquid crystal alignment film irradiated with polarized radiation may be contact-treated with water or a solvent. The solvent used in the above-mentioned contact treatment is not particularly limited as long as it is a solvent that dissolves a decomposed product generated from the liquid crystal alignment film by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, and butyl solvent. Fiber agents, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate, and the like. Among them, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred in terms of versatility or safety of the solvent. More preferred is water, 1-methoxy-2-propanol or ethyl lactate. The solvent may be one type, or two or more types may be combined.

The contact treatment, that is, the treatment in which the liquid crystal alignment film irradiated with the polarized radiation is exposed to water or a solvent, includes an immersion treatment or a spray treatment (also referred to as a spray treatment). The processing time in these processes is preferably 10 seconds to 1 hour in terms of effectively dissolving the decomposition products generated by the liquid crystal alignment film by radiation. Among them, the immersion treatment is preferably 1 minute to 30 minutes. The solvent used in the aforementioned contact treatment may be normal temperature or heated, but is preferably 10 to 80 ° C. Among them, 20 to 50 ° C is preferred. In addition, in terms of the solubility of the decomposed matter, if necessary, ultrasonic treatment or the like may be performed.

After the aforementioned contact treatment, it is preferable to perform washing (also referred to as washing) with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or to burn the liquid crystal alignment film. In this case, either one of cleaning and firing may be performed, or both. The firing temperature is preferably 150 to 300 ° C. Among them, 180 to 250 ° C is more preferable. Even more preferred is 200 ~ 230 ° C. The firing time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is more preferable.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film of a liquid crystal display element of a transverse electric field method such as an IPS method or an FFS method, and can be particularly used as a liquid crystal alignment film of a liquid crystal display element of the FFS method. The liquid crystal display device is obtained by using a liquid crystal cell according to a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention. An example of a method for manufacturing a liquid crystal cell is described by taking a liquid crystal display element having a passive matrix structure as an example. Alternatively, a liquid crystal display element having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting the image display may be used.

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

Next, a liquid crystal alignment film is formed on each of the substrates. On one of the substrates and the other substrate, the liquid crystal alignment films are overlapped with each other, and the periphery is adhered with a sealant. In order to control the substrate gap, a spacer is usually mixed into the sealant, and it is also preferable to disperse the spacer for substrate gap control in the in-plane portion where the sealant is not provided. A part of the sealant is provided with an opening that can be filled with liquid crystal from the outside. Next, a liquid crystal material is injected into a space surrounded by the two substrates and the sealant through an opening provided in the sealant, and then the adhesive seals the opening. For the injection, a vacuum injection method or a method using a capillary phenomenon in the atmosphere may be used. As the liquid crystal material, any of a positive type liquid crystal material and a negative type liquid crystal material can be used. Next, a polarizing plate is provided. Specifically, a pair of polarizing plates are stuck on the surface opposite to the liquid crystal layer of two substrates.

As described above, by using the liquid crystal alignment agent of the present invention, an afterimage caused by AC driving is controlled, and a liquid crystal alignment film having both adhesiveness with a sealant and a base substrate can be obtained. It is particularly useful for a liquid crystal alignment film obtained by irradiating polarized radiation.

[Example]

Examples are given below to explain the present invention more specifically, but the present invention is not limited to these. The abbreviations of the compounds in the following and the methods for measuring each characteristic are as follows. NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolvant DA-1: 1,2-bis (4-aminophenoxy) ethane DA-2: bis (4- Aminophenoxy) methane DA-3: N-tert-butoxycarbonyl-N- (2- (4-aminophenyl) ethyl) -N- (4-aminobenzyl) amine DA- 4: p-phenylenediamine DA-5: Refer to the following formula (DA-5) DA-6: 4,4'-diaminodiphenylamine DA-7: 4,4'-diaminodiphenyl Methane DA-8: Refer to the following formula (DA-8) CA-1: Refer to the following formula (CA-1) CA-2: Refer to the following formula (CA-2) CA-3: Refer to the following formula ( CA-3) CA-4: Refer to the following formula (CA-4) AD-1: Refer to the following formula (AD-1)

[Viscosity] The viscosity of the rhenium solution is measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 ml, a tapered rotor TE-1 (1 ° 34 ', R24), and a temperature of 25 ° .

[Molecular weight] The molecular weight is measured by a GPC (normal temperature gel permeation chromatography) apparatus, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) are calculated from polyethylene glycol and polyethylene oxide conversion values. GPC device: manufactured by Shodex (GPC-101), column: manufactured by Shodex (series of KD803, KD805), column temperature: 50 ° C, eluent: N, N-dimethylformamide (additive is lithium bromide -Hydrate (LiBr ･ H ₂ O) is 30mmol / L, hydrazone phosphate anhydrous crystal (o-phosphoric acid) is 30mmol / L, tetrahydrofuran (THF) is 10ml / L), flow rate: 1.0ml / min

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

[Measurement of 醯 imide ratio] Put 20 mg of poly 醯 imide powder into an NMR sampling tube stand (NMR sampling tube stand, φ5 (made by Kusano Science Co., Ltd.)), and add deuterated dimethyl sulfide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixed product) (0.53ml), completely dissolved by applying ultrasonic waves. This solution was used to measure a proton NMR at 500 MHz with an NMR measuring machine (JNW-ECA500) (manufactured by Datum, Japan). The hydrazone imidization rate is based on protons from structures that have not changed before and after hydrazone imidization, using the proton peak integrated value and the proton peaks from the NH group of sulfamic acid appearing around 9.5 ppm to 10.0 ppm. The integrated value is obtained by the following formula.醯 Imination ratio (%) = (1-α ･ x / y) × 100

In the above formula, x is an integrated peak value of protons derived from the NH group of amidine, y is an integrated peak value of a reference proton, and the reference protons at the time of an α-type polyamidine (amidation ratio is 0%) are relative to The ratio of the number of NH matrix protons of amidine.

[Manufacturing of liquid crystal cell] Fabricate a liquid crystal cell having a structure having a fringe field switching (FFS) mode liquid crystal display element. First, a substrate with electrodes is prepared. The substrate was a glass substrate having a size of 30 mm × 50 mm and a thickness of 0.7 mm. An ITO electrode having a solid pattern is formed on the substrate as a first layer and constitutes a counter electrode. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by a CVD method as a second layer is formed. The SiN film of the second layer has a thickness of 500 nm and functions as an interlayer insulating film. Comb-shaped pixel electrodes formed by patterning the ITO film as the third layer are arranged on the SiN film of the second layer to form two pixels of the first pixel and the second pixel. The size of each pixel is 10mm in length and about 5mm 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-like shape formed by arranging a large number of "く" shaped electrode elements with a curved central portion. The width in the short-side direction of each electrode element is 3 μm, and the interval between the electrode elements is 6 μm. The pixel electrodes forming each pixel are formed by arranging a plurality of electrode elements with a “く” shape that is curved at the central portion. Therefore, the shape of each pixel is not rectangular. The shape of the "く character" of the body. Each pixel is divided up and down with its central curved portion as a boundary, and each pixel has a first region on the upper side and a second region on the lower side.

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

Next, the liquid crystal alignment agent was filtered using a 1.0 μm filter, and then applied to the prepared substrate with electrodes and a glass substrate having a columnar spacer having a height of 4 μm by forming an ITO film on the inner surface by a spin coating method. on. After drying on a hot plate at 80 ° C. for 5 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 20 minutes to form a coating film having a film thickness of 100 nm. This coating film surface was irradiated with ultraviolet light having a wavelength of 254 nm of linearly polarized light having an extinction ratio of 10: 1 or more via a polarizing plate. This substrate was immersed in at least one type of solvent selected from water and organic solvents for 3 minutes, and then immersed in pure water for 1 minute, and heated on a hot plate at 150 ° C to 300 ° C for 5 minutes to obtain a liquid crystal alignment film. Substrate. The above two substrates are used as a set, and a sealant is printed on the substrate so that the other substrate is bonded so that the alignment direction of the liquid crystal alignment film surface is 0 °, and then the sealant is hardened to produce an empty cell. Liquid crystal MLC-3019 (Merck) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cells were heated at 110 ° C. for 1 hour and left for a while, and then used for various evaluations.

[Evaluation of afterimage caused by long-term AC drive] (1) Prepare a liquid crystal cell having the same structure as the liquid crystal cell used for the above-mentioned afterimage evaluation. Using this liquid crystal cell, under a constant temperature environment of 60 ° C, an AC voltage of 60 Hz and ± 5 V was applied for 120 hours. Then, a short-circuited state is formed between the pixel electrode of the liquid crystal cell and the counter electrode, and in this state, it is left at room temperature for one day.

After being placed, the liquid crystal cell is placed between two polarizing plates with orthogonally arranged polarizing axes, and the backlight is turned on with no voltage applied, and the arrangement angle of the liquid crystal cell is adjusted to minimize the brightness of the transmitted light. Then, from the angle at which the second region of the first pixel becomes the darkest to the angle at which the first region becomes the darkest, the rotation angle when the liquid crystal cell is rotated is calculated as the angle Δ. Similarly for the second pixel, the second region is compared with the first region, and the same angle Δ is calculated.

[Evaluation of pencil hardness] A sample for pencil hardness evaluation was prepared as follows. A liquid crystal alignment agent was applied on a 30 mm × 40 mm ITO substrate by a spin coating method. After drying on a hot plate at 80 ° C. for 2 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a film thickness of 100 nm. This coating film surface is subjected to an alignment treatment such as rubbing or polarized ultraviolet radiation to obtain a substrate with a liquid crystal alignment film. This substrate was immersed in at least one type of solvent selected from water and organic solvents for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 ° C to 300 ° C for 14 minutes to obtain a liquid crystal alignment film. Substrate. This substrate was measured by a pencil hardness test method (JIS K5400).

[Evaluation of Adhesion] The samples for evaluation of adhesion were prepared as follows. Using a spin coater, the liquid crystal alignment agent was applied to an ITO substrate of 30 mm × 40 mm. Next, after drying on a hot plate at 80 ° C. for 2 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a film thickness of 100 nm. This coating film surface is subjected to an alignment treatment such as rubbing or polarized ultraviolet radiation to obtain a substrate with a liquid crystal alignment film. This substrate was immersed in at least one type of solvent selected from water and organic solvents for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 ° C to 300 ° C for 14 minutes to obtain a liquid crystal alignment film. Substrate.

After preparing the two substrates prepared above, one of the substrates was coated with a 4 μm bead spacer on the liquid crystal alignment film surface, and the sealant (XN-1500T manufactured by Kyoritsu Chemical) was dropped. Next, the liquid crystal alignment film surface of the other substrate is used as the inner side, and the overlapping width of the substrate is 1 cm. At this time, the dripping amount of the sealant was adjusted so that the diameter of the sealant after bonding was 3 mm. The two bonded substrates were fixed with a jig, and then thermally cured at 150 ° C. for 1 hour to prepare a sample for evaluation of adhesion. Then, the sample substrate was a desktop precision universal testing machine AGS-X 500N made by Shimadzu Corporation, the end portions of the upper and lower substrates were fixed, and then the upper portion of the central portion of the substrate was pressed tightly to measure the pressure (N) at the time of peeling.

<Synthesis Example 1> DA-1 (2.78g, 11.4mmol), DA-2 (3.50g, 15.2mmol), and DA-3 (3.89) were weighed out in a 100ml four-necked flask equipped with a stirring device and a nitrogen-containing introduction tube. g, 11.4 mmol), 46.3 g of NMP was added, and the solution was stirred while being fed with nitrogen. While stirring this diamine solution, CA-1 (6.64g, 29.6mmol), CA-2 (1.42g, 5.70mmol) were added, and 36.8g of NMP was added to adjust the solid content concentration to 18% by mass at 40 ° C. After stirring for 24 hours, a polyamic acid solution (A) (viscosity: 850 mPams) was obtained. The molecular weight of polyamic acid is Mn = 15500 and Mw = 36500.

<Synthesis Examples 2 to 12> Using the diamine component, the tetracarboxylic acid component, and NMP shown in Table 1 below, the reaction temperature and the solid content concentration were respectively implemented in the same manner as in Synthesis Example 1 to obtain the following Table 1 Polyamic acid solution (B) ~ (L). The viscosity and molecular weight of the obtained polyamic acid are shown in Table 1 below.

<Synthesis Example 13> In a 100 ml four-necked flask equipped with a stirring device and a nitrogen-containing introduction tube, 30 g of the obtained polyamic acid solution (A) was weighed, 15.0 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyfluorenic acid solution, 3.32 g of acetic anhydride and 0.43 g of pyridine were added, and the mixture was heated at 55 ° C. for 3 hours to perform chemical fluorination. The obtained reaction solution was put into 213 ml of methanol while stirring, and the precipitate was collected by filtration, and then washed three times with 213 ml of methanol. The obtained resin powder was dried at 60 ° C for 12 hours to obtain a polyimide resin powder (A). The polyimide resin powder had an imidization ratio of 65%, Mn = 6800, and Mw = 12000.

<Synthesis Examples 14 to 23> The polyfluorene solution shown in Table 2 below was used, and NMP, acetic anhydride, pyridine, and methanol were used in the same manner as in Synthesis Example 13 to obtain the polyfluorene shown in Table 2 below. Imine resin powder (B) ~ (K).

<Synthesis Examples 24 to 28> The diamine component, tetracarboxylic acid component, and NMP shown in Table 1-2 below were used, and then the reaction temperature and solid content concentration were implemented in the same manner as in Synthesis Example 1, and Table 1 below was obtained. Polyamine solutions (M) to (Q) shown in -2. The viscosity and molecular weight of the obtained polyamic acid are shown in Table 1-2 below.

<Synthesis Examples 29 to 31> Except that the polyamic acid solution, NMP, acetic anhydride, pyridine, and methanol shown in Table 2 were used, the same procedures as in Synthesis Example 13 were performed to obtain the compounds shown in Table 2-2 below. Polyimide resin powder (M) ~ (Q).

<Example 1> In a 100 ml conical flask, weigh 10.00 g of the 18% by mass polyamic acid solution (A) obtained in Synthesis Example 1, add 14.00 g of NMP and 6.00 g of BCS, and mix at 25 ° C for 8 hours. A liquid crystal alignment agent (1) was obtained. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Example 2> 1. In a 100 ml Erlenmeyer flask, 1.80 g of polyimide resin powder (A) obtained in Synthesis Example 13 was weighed, and 10.2 g of NMP was added to make the solid content concentration 15%, and the mixture was stirred at 70 ° C. for 24 hours to Dissolved to obtain a polyfluoreneimine solution (K). AD-1 (0.09 g), 2.90 g of NMP, 9.00 g of GBL, and 6.00 g of BCS were added to this polyimide solution, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (2). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Examples 3 to 5> A polyimide resin powder (B) to (D) was used instead of polyimide resin powder (A), and the same procedure as in Example 2 was performed to obtain a liquid crystal alignment agent (3) to ( 5).

〈Example 6〉 In a 100 ml Erlenmeyer flask, weigh 5.50 g of the 15% by mass polyimide solution (D) obtained in Example 5 and 5.50g of the 15% by mass polyimide solution (E), and add AD. -1 (0.83g), NMP 4.82g, GBL 7.35g, BCS 6.00g, and stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (6). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Examples 7 to 8> The same procedure as in Example 2 was performed except that polyimide resin powders (E) to (F) were used instead of polyimide resin powder (A) to obtain liquid crystal alignment agents (7) to ( 8).

<Comparative Example 1> A liquid crystal alignment agent (9) was obtained in the same manner as in Example 1 except that the polyamic acid solution (H) was used instead of the polyamino acid solution (A).

<Comparative Examples 2 to 6> A polyimide resin powder (G) to (K) was used in place of the polyimide resin powder (A), and the same procedure as in Example 2 was performed to obtain a liquid crystal alignment agent (10) to ( 14).

<Example 9> After the liquid crystal alignment agent (1) obtained in Example 1 was filtered through a 1.0 μm filter, it was coated by spin coating on the prepared substrate with an electrode and an ITO film formed on the inner surface. On a glass substrate with a columnar spacer having a height of 4 μm. After drying on a hot plate at 80 ° C. for 5 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 20 minutes to form a coating film having a film thickness of 100 nm. This coating film surface was irradiated with ultraviolet light of 0.25 J / cm ² at a wavelength of 254 nm of linearly polarized light having an extinction ratio of 26: 1 through a polarizing plate. This substrate was immersed in a mixed solution of pure water: 2-propanol = 1/1 for 3 minutes, then immersed in pure water for 1 minute, and heated on a heating plate at 230 ° C for 14 minutes to obtain a substrate with a liquid crystal alignment film. .

Using the two substrates obtained above as a set, a sealant was printed on the substrate, and the other substrate was bonded so that the alignment direction of the liquid crystal alignment film surface was 0 °, and then the sealant was hardened to produce an empty crystal. Cell. Liquid crystal MLC-3019 (Merck) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cells were heated at 110 ° C. for 1 hour and left for a while, and then the afterimage evaluation by long-term AC driving was performed. The value of the angle Δ of the liquid crystal cell after long-term AC driving is 0.20.

<Examples 10 to 16 and Comparative Examples 7 to 12> Except that the liquid crystal alignment agent (1) shown in Table 3 was used instead of the liquid crystal alignment agent (1), and the irradiation amount of ultraviolet rays and the dipping solution were as shown in Table 3. In the same manner as in Example 9, an FFS-driven liquid crystal cell was produced, and an afterimage evaluation by long-term AC driving was performed. The values of the angles Δ of the liquid crystal cells after the respective long-term AC driving are shown in Table 3.

<Example 17> After the above-mentioned liquid crystal alignment agent (1) was filtered through a filter of 1.0 μm, it was coated by spin coating on the prepared electrode-attached substrate and an ITO film having a height of 4 μm to form an ITO film on the inner surface. Spacers on a glass substrate. After drying on a hot plate at 80 ° C. for 5 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 20 minutes to form a coating film having a film thickness of 100 nm. This coating film surface was irradiated with a linearly polarized light with an extinction ratio of 26: 1 and a wavelength of 254 nm of ultraviolet light of 0.25 J / cm ² through a polarizing plate, and immersed in a mixed solution of pure water: 2-propanol = 1/1 for 5 minutes, The substrate was immersed in pure water for 1 minute and heated on a hot plate at 230 ° C. for 14 minutes to obtain a substrate with a liquid crystal alignment film. As a result of measuring the substrate by a pencil hardness test method (JIS K5400), it was 3H.

<Examples 18 to 25 and Comparative Examples 13 to 18> Except that the liquid crystal alignment agent (1) shown in Table 4 was used instead of the liquid crystal alignment agent (1), and the irradiation amount of ultraviolet rays and the dipping solution were as shown in Table 4. In the same manner as in Example 17, samples for a pencil hardness test were prepared. Table 4 shows the results of the respective pencil hardness tests.

<Example 26> (1) The liquid crystal alignment agent (1) obtained in Example 1 was filtered through a 1.0 μm filter, and then applied to a 30 mm × 40 mm ITO substrate by a spin coating method. After drying on a hot plate at 80 ° C. for 2 minutes, firing was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a film thickness of 100 nm. This coating film surface was rubbed with a rayon cloth using a friction device with a roller diameter of 120 mm under the conditions of 300 rpm of the roller rotation speed, 20 mm / sec of the roller speed, and an insertion amount of 0.1 mm, immersed in pure water for 1 minute, The substrate was washed with ultrasonic waves and dried in a thermal cycle oven at 80 ° C to obtain a substrate with a liquid crystal alignment film.

The two substrates prepared as described above were prepared, and the liquid crystal alignment film surface of one of the substrates was coated with a 4 μm bead spacer, and then a sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was dropped. Next, the liquid crystal alignment film surface of the other substrate is used as the inner side, and the overlapping width of the substrate is 1 cm. At this time, the dripping amount of the sealant was adjusted so that the diameter of the sealant after bonding was 3 mm. The two bonded substrates were fixed with a jig, and then thermally cured at 150 ° C. for 1 hour to prepare a sample for evaluation of adhesion. As a result of evaluation of adhesion, the strength at the time of peeling was 20N.

<Examples 27 to 33, and Comparative Examples 19 to 24> Except that the liquid crystal alignment agent (1) shown in Table 5 was used instead of the liquid crystal alignment agent (1), and the irradiation amount of ultraviolet rays and the dipping solution were as shown in Table 5. Using the same method as in Example 26, a sample for adhesion evaluation was prepared. The results of the adhesion evaluation are shown in Table 5.

<Example 34> In a 100 ml Erlenmeyer flask, 1.80 g of the polyimide resin powder (M) obtained in Synthesis Example 29 was weighed, and 10.2 g of NMP was added to make the solid content concentration 15%, and then the mixture was stirred at 70 ° C. for 24 hours. The solution was dissolved in 1 hour to obtain a polyfluoreneimine solution (M). AD-1 (0.09 g), 2.90 g of NMP, 9.00 g of GBL, and 6.00 g of BCS were added to the polyimide solution, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (15). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Example 35> In a 100 ml conical flask, weigh 6.00 g of a 15% by mass polyimide solution (M) prepared in the same manner as in Example 34 and a 15% by mass polyimide solution obtained in Synthesis Example 25. (N) 6.00 g, and then AD-1 (0.09 g), NMP 2.90 g, GBL 9.00 g, and BCS 6.00 g were added and stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (16). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Example 36> In a 100 ml conical flask, 1.80 g of the polyimide resin powder (O) obtained in Synthesis Example 30 was weighed, and 10.2 g of NMP was added to make the solid content concentration 15%. Then, the mixture was stirred at 70 ° C. for 24 hours. It was dissolved in hours to obtain a polyfluoreneimine solution (O). To this polyimide solution, AD-1 (0.09 g), NMP 2.90 g, GBL 9.00 g, and BCS 6.00 g were added and stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (17). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Example 37> In a 100 ml conical flask, weigh 6.00 g of a 15% by mass polyimide solution (O) prepared in the same manner as in Example 36 and a 15% by mass polyimide solution obtained in Synthesis Example 5. (E) 6.00 g, then AD-1 (0.09 g), NMP 2.90 g, GBL 9.00 g, and BCS 6.00 g were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (18). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed to be a uniform solution.

<Examples 38 to 39> A polyimide resin powder (Q) to (P) was used in place of the polyimide resin powder (M), and the same procedure as in Example 34 was performed to obtain a liquid crystal alignment agent (19) to ( 20).

<Examples 40 to 45> Use the liquid crystal alignment agent shown in Table 3-2 in place of the liquid crystal alignment agent (1), and the irradiation amount of ultraviolet rays and the dipping solution are set as shown in Table 3-2. An FFS-driven liquid crystal cell was produced in the same manner as in Example 9, and the afterimage evaluation by long-term AC driving was performed. The value of the angle Δ of the liquid crystal cell after the respective long-term AC driving is shown in Table 3-2.

<Examples 46 to 51> Use the liquid crystal alignment agent shown in Table 4-2 instead of the liquid crystal alignment agent (1), and set the exposure amount of ultraviolet rays and the dipping solution as shown in Table 4-2. In the same manner as in Example 17, samples for a pencil hardness test were prepared. The results of the respective pencil hardness tests are shown in Table 4-2.

<Examples 52 to 57> Use the liquid crystal alignment agent shown in Table 5-2 in place of the liquid crystal alignment agent (1), and the irradiation amount of ultraviolet rays and the dipping solution are set as shown in Table 5-2. In the same manner as in Example 26, a sample for adhesion evaluation was prepared. The results of the adhesion evaluation are shown in Table 5-2.

[Industrial availability]

With the liquid crystal alignment agent of the present invention, in addition to good afterimage characteristics, a liquid crystal alignment film having high film hardness and sealing adhesion can be obtained. Therefore, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention has a high yield rate and can reduce the afterimage caused by the AC drive generated in the liquid crystal display element of the IPS driving method or the FFS driving method, and can be obtained. Liquid crystal display element with IPS drive method or FFS drive method with excellent afterimage characteristics. Therefore, it can be used for a liquid crystal display element which requires high display quality.

Claims (9)

A liquid crystal alignment agent, which is characterized by containing at least one selected from the group consisting of tetracarboxylic dianhydride and derivatives thereof selected from the group consisting of the following formula (1), and a group selected from the group consisting of four groups represented by the following formula (2): Tetracarboxylic acid derivative components of at least one type of carboxylic dianhydride and its derivative; and a diamine component containing at least one type of diamine selected from the following formulae (3) and (4); the obtained polyfluorene A polymer of at least one kind of imine precursor and polyimide of amidine imide, In the formula, X ₁ is a structure selected from the following formulae (X1-1) to (X1-4), and X ₂ is a structure selected from the following formulas (X2-1) to (X2-2). In the formula, R ₃ to R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, and a carbon number containing a fluorine atom. 1 to 6 monovalent organic groups or phenyl groups may be the same or different, but at least one is other than a hydrogen atom, and R ₇ to R ₂₃ are each independently a hydrogen atom, a halogen atom, and an alkane having 1 to 6 carbon atoms Radicals, alkenyl radicals having 2 to 6 carbon atoms, alkynyl radicals having 2 to 6 carbon atoms, monovalent organic radicals having 1 to 6 carbon atoms containing fluorine atoms, or phenyl groups may be the same or different, In the formula, A ₁ is a single bond, an ester bond, a amine bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms, and A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amine group, a thiol group, or a nitrate. Group, phosphate group, or monovalent organic group having 1 to 20 carbon atoms, where a is an integer of 1 to 4, and when a is 2 or more, the structures of A ₁ may be the same or different, and b and c are each independently 1 Integer of ~ 2. For example, the liquid crystal alignment agent of claim 1, wherein the ratio of the tetracarboxylic dianhydride or its derivative represented by the aforementioned formula (2) is 1 to 30 mol% relative to 1 mole of the all-tetracarboxylic acid derivative component. For example, the liquid crystal alignment agent of claim 1, wherein the structure of X ₁ is at least one selected from the following formulae (X1-12) to (X1-16), . For example, the liquid crystal alignment agent of claim 1, wherein the structure of X ₁ is the aforementioned formula (X1-12). For example, the liquid crystal alignment agent of claim 1, wherein the structure of X ₂ is represented by the aforementioned formula (X2-1). For example, the liquid crystal alignment agent of claim 1, wherein the diamine component contains at least one selected from the following formulae (DA-1) to (DA-20), . A liquid crystal alignment film is obtained by the liquid crystal alignment agent according to any one of claim 1 to claim 6. A liquid crystal display element is provided with the liquid crystal alignment film as claimed in claim 7. The liquid crystal display device according to claim 8, wherein the liquid crystal display device is a device that drives a liquid crystal with a transverse electric field.