WO2018117240A1

WO2018117240A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2018117240A1
Application number: PCT/JP2017/046016
Authority: WO
Inventors: 奈穂国見; 泰宏宮本; 祟明杉山
Original assignee: 日産化学工業株式会社
Priority date: 2016-12-21
Filing date: 2017-12-21
Publication date: 2018-06-28
Also published as: KR102593074B1; CN110325902B; TWI820011B; JP7239872B2; CN110325902A; JPWO2018117240A1; KR20190095405A; TW201840644A

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 aligning agent, liquid crystal aligning film, and liquid crystal display element

The present invention relates to a liquid crystal aligning agent used for manufacturing a liquid crystal display element, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the liquid crystal aligning film.

Liquid crystal display elements used for 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 crystals. Currently, the most widely used liquid crystal alignment film in the industry is the surface of a film made of polyamic acid and / or polyimide imidized with a cloth made of cotton, nylon, polyester, etc. formed on an electrode substrate. It is manufactured by performing a so-called rubbing process that rubs in one direction.

The rubbing treatment of the film surface in the alignment process of the liquid crystal alignment film is an industrially useful method that is simple and excellent in productivity. However, the demand for higher performance, higher definition, and larger size of liquid crystal display elements is increasing, and the surface of the alignment film caused by rubbing treatment, dust generation, the influence of mechanical force and static electricity, Various problems such as non-uniformity in the orientation processing surface have become apparent. As a liquid crystal alignment treatment method that replaces the rubbing treatment, a photo alignment method that imparts liquid crystal alignment ability by irradiating polarized radiation is known. As liquid crystal alignment treatment by the photo-alignment method, those utilizing a photoisomerization reaction, those utilizing a photocrosslinking reaction, those utilizing a photodecomposition reaction, and the like have been proposed (see Non-Patent Document 1).

In Patent Document 1, it is proposed to use a polyimide film having an alicyclic structure such as a cyclobutane ring in the main chain for the photo-alignment method. The photo-alignment method as described above can impart liquid crystal alignment ability by an industrially simple manufacturing process. In addition, in a liquid crystal display element of an IPS driving method or a fringe field switching (hereinafter referred to as FFS) driving method, a liquid crystal alignment film to which liquid crystal alignment capability is imparted by a photo-alignment method is imparted with liquid crystal alignment capability by rubbing treatment. Compared with the liquid crystal alignment film, the contrast and viewing angle characteristics of the liquid crystal display element can be improved. As described above, the photo-alignment method as described above is attracting attention as a promising liquid crystal alignment method because it can improve the performance of the liquid crystal display element. The liquid crystal alignment film used in the liquid crystal display element of the IPS driving method or the FFS driving method is generated in the liquid crystal display element of the IPS driving method or the FFS driving method in addition to the basic characteristics such as excellent liquid crystal alignment property and electrical characteristics. It is necessary to suppress afterimages by long-term AC driving.

JP-A-9-297313

The present invention relates to a liquid crystal aligning agent capable of suppressing an afterimage due to long-term alternating current driving generated 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 aligning agent, and a liquid crystal display having the liquid crystal alignment film An object is to provide an element.

In order to achieve the above object, the present inventors have made extensive studies, and as a result, a polyimide obtained from a tetracarboxylic acid derivative component having a tetracarboxylic acid derivative having a specific structure and a diamine component having a specific structure, Or it discovered that said objective could be achieved by using the liquid crystal aligning agent containing a polyimide precursor. Thus, the present invention has the following gist.

1. At least one selected from tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and at least one selected from tetracarboxylic dianhydrides represented by the following formula (2) and derivatives thereof. And a tetracarboxylic acid derivative component containing, a diamine component containing at least one diamine selected from the following formulas (3) and (4), and a polyimide precursor obtained from the polyimide that is an imidized product thereof A liquid crystal aligning agent containing at least one selected polymer.

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

In the formula, each of R ₃ to R ₆ independently represents 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, or a fluorine atom. It is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, and 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, or a carbon containing a fluorine atom. These are monovalent organic groups having 1 to 6 or phenyl groups, which may be the same or different.

In the formula, 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, and A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol Group, nitro group, phosphate group, or monovalent organic group having 1 to 20 carbon atoms, a is an integer of 1 to 4, and when a is 2 or more, the structure of A ₁ is the same or different. Also good. b and c are each independently an integer of 1 to 2.

2. The ratio of the tetracarboxylic dianhydride represented by the formula (2) or a derivative thereof is 1 to 30 mol% with respect to 1 mol of all tetracarboxylic derivative components. Liquid crystal aligning agent as described in.

3. _1. The structure of X ₁ is at least one selected from the following formulas (X1-12) to (X1-16): Or 2. Liquid crystal aligning agent as described in.

4). The structure of X ₁ is the formula (X1-12); To 3. The liquid crystal aligning agent as described in any one of these.

5). The structure of X ₂ is represented by the formula (X2-1). To 4. The liquid crystal aligning agent as described in any one of these.

6. The diamine component contains at least one selected from the following formulas (DA-1) to (DA-20): To 5. The liquid crystal aligning agent of any one of these.

7. 1. To 6. Liquid crystal aligning film obtained from the liquid crystal aligning agent as described in any one of these.

8. 7. The liquid crystal display element which comprises the liquid crystal aligning film of description.

9. 7. The liquid crystal display element drives the liquid crystal by a lateral electric field, A liquid crystal display element according to 1.

According to the liquid crystal aligning agent of the present invention, in addition to being excellent in basic characteristics such as liquid crystal alignment and electrical characteristics, it is possible to suppress afterimages caused by long-term alternating current driving that occur in liquid crystal display elements of IPS driving method and FFS driving method. A liquid crystal alignment film that can be obtained can be obtained.

Further, according to the liquid crystal alignment film and the liquid crystal display element of the present invention, in addition to being excellent in basic characteristics such as liquid crystal alignment and electrical characteristics, long-term AC driving that occurs in IPS driving and FFS driving liquid crystal display elements. Afterimage can be suppressed.

The liquid crystal aligning agent of the present invention contains at least one polymer (hereinafter also referred to as a specific polymer) selected from the polyimide precursor described above and a polyimide that is an imidized product thereof. Hereafter, each component used as the raw material which makes a specific polymer is explained in full detail.

<Tetracarboxylic acid derivative component>
The tetracarboxylic acid derivative component used for the polymerization of the specific polymer contained in the liquid crystal aligning agent of the present invention includes not only tetracarboxylic dianhydride but also tetracarboxylic acid and tetracarboxylic acid that are tetracarboxylic acid derivatives thereof. An acid dihalide compound, a tetracarboxylic acid dialkyl ester compound or a tetracarboxylic acid dialkyl ester dihalide compound can be used. The tetracarboxylic dianhydride or derivative thereof used for the polymerization of the specific polymer is at least one selected from tetracarboxylic dianhydrides or derivatives thereof represented by the following formula (1), and the following formula (2): And at least one selected from tetracarboxylic acids represented by

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

From the viewpoint of suppressing afterimages due to long-term alternating current drive, the structure of X ₁ is preferably at least one selected from structures represented by the following formulas (X1-12) to (X1-16), and the following formula (X1- 12) is particularly preferred.

The proportion of the tetracarboxylic dianhydride represented by the above formula (1) or a derivative thereof is preferably 50 mol% or more, more preferably 70 mol% or more with respect to 1 mol of all tetracarboxylic dianhydrides or derivatives thereof. Preferably, 80 mol% or more is more preferable.

X ₂ is a structure selected from the following formulas (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 suppression of afterimages caused by long-term alternating current driving. The ratio of the tetracarboxylic dianhydride represented by the above formula (2) or a derivative thereof is 1 to 30 mol% with respect to 1 mol of the total tetracarboxylic dianhydride or the derivative thereof (total tetracarboxylic acid derivative component). It is preferably 10 to 30%, more preferably 10 to 20%.

In addition to the above formulas (1) and (2), the tetracarboxylic dianhydride and its derivative used for the polymerization of the specific polymer are the tetracarboxylic dianhydride and its derivative represented by the following formula (6). It may be used.

In the formula, X ₃ is a tetravalent organic group, and its structure is not particularly limited. Specific examples include structures of the following formulas (X-9) to (X-47). From the viewpoint of easy availability of the compound, the structure of X ₃ is 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. Further, from the viewpoint of obtaining a liquid crystal alignment film in which the residual charge accumulated by direct current voltage can be quickly relaxed, it is preferable to use a tetracarboxylic dianhydride having an aromatic ring structure. As the structure of X ₃ , X-26 X-27, X-28, X-32, X-35, and X-37 are more preferable.

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

From the standpoint of suppressing afterimages due to long-term alternating current drive, the structures of the following formulas (DA-1) to (DA-20) are preferable as the specific structures of the above formulas (3) and (4). Of 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 mol%, more preferably 70 mol% to 100 mol%, relative to 1 mol of all diamine components. preferable. The diamine used for the polymerization of the specific polymer may include a diamine represented by the following formula (7) in addition to the above formulas (3) and (4).

In the formula, each A ₃ independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms, which may be the same or different. Good. From the viewpoint of liquid crystal orientation, 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 formulas (Y-1) to (Y-49) and (Y-57) to (Y-168).

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

In the formula, D is a t-butoxycarbonyl group.

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

<Method for producing polyamic acid ester>
The polyamic acid ester, which is a polyimide precursor used in the present invention, can be synthesized by any of the following methods (1) to (3).

(1) When synthesizing from polyamic acid Polyamic acid ester can be synthesized by esterifying polyamic acid obtained from tetracarboxylic dianhydride and diamine. Specifically, the polyamic acid and the esterifying agent are synthesized by reacting 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 to 4 hours. be able to.

The esterifying agent is preferably one that can be easily removed by purification, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents, and more preferably 2 to 4 molar equivalents, per 1 mol of the polyamic acid repeating unit.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. from the solubility of the polymer, and these are used alone or in combination of two or more. May be. The concentration of the polymer in the organic solvent at the time of synthesis is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that the polymer hardly precipitates and a high molecular weight product is easily obtained.

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

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The addition amount of the base is preferably 2 to 4 times mol, preferably 2 to 3 times mol with respect to tetracarboxylic acid diester dichloride, from the viewpoint of easy removal and high molecular weight. More preferred. The organic solvent used in the above reaction is preferably N-methyl-2-pyrrolidone, γ-butyrolactone or the like in view of the solubility of the monomer and polymer, and these may be used alone or in combination.

The polymer concentration in the organic solvent at the time of synthesis is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that the polymer is hardly precipitated and a high molecular weight product is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the organic solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and the reaction is preferably performed in a nitrogen atmosphere to prevent mixing of outside air. .

(3) When a polyamic acid is synthesized from a tetracarboxylic acid diester and a diamine The polyamic acid ester can be synthesized by polycondensation of a tetracarboxylic acid diester and a diamine. Specifically, tetracarboxylic diester and diamine are reacted in the presence of a condensing agent, a base, and an organic solvent at 0 to 150 ° C., preferably 0 to 100 ° C., for 30 minutes to 24 hours, preferably 3 to 15 hours. Can be synthesized.

Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazide. Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like. The addition amount of the condensing agent is preferably 2 to 3 moles, more preferably 2 to 2.5 moles, relative to the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 moles, more preferably 2 to 3 moles, relative to the diamine component from the viewpoint of easy removal and high molecular weight. Examples of the organic solvent include N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide and the like. In the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0 to 1.0-fold mol, more preferably 2.0 to 3.0-fold mol based on the diamine component.

Among the methods for synthesizing the three polyamic acid esters, since the high molecular weight polyamic acid ester is obtained, the synthesis method (1) or (2) is particularly preferable. The polyamic acid ester solution obtained as described above can be polymerized by being poured into a poor solvent while being well stirred. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. The poor 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, 2-propanol and the like are preferable.

<Method for producing polyamic acid>
The polyamic acid which is a polyimide precursor used in the present invention can be synthesized by the following method. Specifically, tetracarboxylic dianhydride and diamine are 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 to 12 hours. Can be synthesized.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. in view of the solubility of the monomer and polymer. These may be used alone or in combination of two or more. May be used. The concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is difficult to occur and a high molecular weight product is easily obtained.

The polyamic acid obtained as described above can be recovered by precipitating a polymer by pouring into a poor solvent while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. The poor 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, 2-propanol and the like are preferable.

<Production method of polyimide>
The polyimide used in the present invention can be produced by imidizing the polyamic acid ester or polyamic acid. When a polyimide is produced from a polyamic acid ester, chemical imidation by adding a basic catalyst to the polyamic acid ester solution or a polyamic acid solution obtained by dissolving the polyamic acid ester resin powder in an organic solvent is simple. . Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is unlikely to decrease during the imidization process.

Chemical imidation can be performed by stirring the polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature for carrying out the imidization reaction is −20 to 140 ° C., preferably 0 to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times mol, preferably 2 to 20 times mol of the amic acid ester group. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

When a polyimide is produced from a polyamic acid, chemical imidization in which a catalyst is added to the polyamic acid solution obtained by the reaction of a diamine component and tetracarboxylic dianhydride is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not easily decrease during the imidization process.

Chemical imidation can be performed by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, pyridine is preferable because it has an appropriate basicity for proceeding with the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like. Among them, use of acetic anhydride is preferable because purification after completion of the reaction is facilitated.

The temperature for carrying out the imidization reaction is −20 to 140 ° C., preferably 0 to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times mol, preferably 2 to 20 times mol of the polyamic acid group, and the amount of acid anhydride is 1 to 50 times mol, preferably 3 to 30 times mol of the polyamic acid group. Is a mole. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. In the solution after the imidation reaction of polyamic acid ester or polyamic acid, the added catalyst and the like remain, so the obtained imidized polymer is recovered by the means described below, and redissolved in an organic solvent. Thus, the liquid crystal aligning agent of the present invention is preferable.

The polyimide solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a polymer powder purified by drying at normal temperature or by heating can be obtained. Examples of the poor solvent include, but are not limited to, methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, and the like. Methanol, ethanol, 2-propanol, Acetone is preferred.

<Liquid crystal aligning agent>
The liquid crystal aligning agent used in the present invention has a form of a solution in which a polymer component is dissolved in an organic solvent. The molecular weight of the polymer is preferably 2,000 to 500,000 in terms of 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 aligning agent used in the present invention can be appropriately changed by setting the thickness of the coating film to be formed, but it is 1 mass from the point of forming a uniform and defect-free coating film. % From the viewpoint of storage stability of the solution, and preferably 10% by mass or less. A particularly preferred polymer concentration is 2 to 8% by mass.

The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2 -Pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, 3-methoxy-N, N-dimethylpropanamide and the like. You may use these 1 type or in mixture of 2 or more types. Moreover, even if it is a solvent which cannot melt | dissolve a polymer component uniformly by itself, if it is a range which a polymer does not precipitate, you may mix with said organic solvent.

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

In addition to the above, the liquid crystal aligning agent of the present invention includes a polymer other than the specific polymer, a dielectric or conductive material for changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film, the liquid crystal aligning film and the substrate. Silane coupling agent for the purpose of improving adhesion with the liquid crystal, crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film, and polyamic acid imidization when baking the coating film An imidization accelerator for the purpose of proceeding efficiently may be added.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film is a film obtained by applying the above liquid crystal aligning agent to a substrate, drying and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with a glass substrate or a silicon nitride substrate. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed in terms of simplification of the process. In the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one substrate is used, and a material that reflects light such as aluminum can be used for the electrode in this case.

The application method of the liquid crystal aligning agent is not particularly limited, but industrially, a method of screen printing, offset printing, flexographic printing, an ink jet method, or the like is common. Other coating methods include a dipping method, a roll coater method, a slit coat method, a spinner method, or a spray method, and these may be used depending on the purpose.

After the liquid crystal aligning agent is applied on the substrate, the solvent can be evaporated by a heating means such as a hot plate, a thermal circulation oven or an IR (infrared) oven to form a liquid crystal alignment film. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, a condition of baking at 50 to 120 ° C. for 1 to 10 minutes and then baking at 150 to 300 ° C. for 5 to 120 minutes is mentioned in order to sufficiently remove the contained solvent. If the thickness of the liquid crystal alignment film after baking is too thin, the reliability of the liquid crystal display element may be lowered, and thus it is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

The method of aligning the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention is preferably a photo alignment method. As a preferred example of the photo-alignment method, the surface of the liquid crystal alignment film is irradiated with radiation deflected in a certain direction, and in some cases, preferably, a heat treatment is performed at a temperature of 150 to 250 ° C. A liquid crystal alignment ability). As the radiation, ultraviolet rays or visible rays having a wavelength of 100 to 800 nm can be used. Among these, ultraviolet rays having a wavelength of preferably 100 to 400 nm, more preferably 200 to 400 nm are preferable.

Further, in order to improve the liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be irradiated with radiation while heating at 50 to 250 ° C. The radiation dose is preferably 1 to 10,000 mJ / cm ² . Of these, 100 to 5,000 mJ / cm ² is preferable. The liquid crystal alignment film thus prepared can stably align liquid crystal molecules in a certain direction. A higher extinction ratio of polarized ultraviolet rays is preferable because higher anisotropy can be imparted. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10: 1 or more, and more preferably 20: 1 or more.

Furthermore, the liquid crystal alignment film irradiated with polarized radiation can be subjected to contact treatment using water or a solvent by the above method. The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves a decomposition 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, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Examples thereof include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate or cyclohexyl acetate. Of these, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable from the viewpoint of versatility and solvent safety. More preferred is water, 1-methoxy-2-propanol or ethyl lactate. The solvent may be used alone or in combination of two or more.

Examples of the above-described contact treatment, that is, treatment for bringing water or a solvent into contact with the liquid crystal alignment film irradiated with polarized radiation include immersion treatment and spray treatment (also referred to as spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour from the viewpoint of efficiently dissolving the decomposition products generated from the liquid crystal alignment film by radiation. In particular, the immersion treatment is preferably performed for 1 minute to 30 minutes. The solvent used in the contact treatment may be warmed at normal temperature, but is preferably 10 to 80 ° C. Of these, 20 to 50 ° C. is preferable. In addition, from the viewpoint of the solubility of the decomposition product, ultrasonic treatment or the like may be performed as necessary.

After the contact treatment, it is preferable to perform rinsing (also referred to as rinsing) with a low-boiling solvent such as water, methanol, ethanol, 2-propanol, acetone or methyl ethyl ketone, and baking of the liquid crystal alignment film. At that time, either one of rinsing and firing, or both may be performed. The firing temperature is preferably 150 to 300 ° C. Of these, 180 to 250 ° C. is preferable. More preferably, the temperature is 200 to 230 ° C. The firing time is preferably 10 seconds to 30 minutes. Among these, 1 to 10 minutes is preferable.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a horizontal electric field type liquid crystal display element such as an IPS mode or an FFS mode, and is particularly useful as a liquid crystal alignment film for an FFS mode liquid crystal display element. The liquid crystal display element is obtained using a liquid crystal cell by preparing a liquid crystal cell by a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention. As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. In addition, the liquid crystal display element of the active matrix structure in which switching elements, such as TFT (Thin Film Transistor), were provided in each pixel part which comprises image display may be sufficient.

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 ITO electrodes, for example, and are patterned so as to display 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 can be, 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, the other substrate is overlapped with one substrate so that the liquid crystal alignment film faces each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealant, and it is preferable to spray a spacer for controlling the substrate gap on the in-plane portion where no sealant is 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 the space surrounded by the two substrates and the sealing agent through the opening provided in the sealing agent, and then the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. As the liquid crystal material, either a positive liquid crystal material or a negative liquid crystal material may be used. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer.

As described above, by using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning film that suppresses an afterimage due to AC driving and has both adhesiveness with a sealing agent and a base substrate. In particular, it is useful for a liquid crystal alignment film obtained by irradiating polarized radiation.

Examples Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The following are the abbreviations of the compounds and the measurement methods of the respective properties.
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve 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: See formula (DA-5) below DA-6: 4,4′-diaminodiphenylamine DA-7: 4,4′-diaminodiphenylmethane DA-8: See formula (DA-8) below CA-1: See Formula (CA-1) below CA-2: See Formula (CA-2) below CA-3: See Formula (CA-3) below CA-4: See Formula (CA-4) below AD-1: Formula below See (AD-1)

[viscosity]
The viscosity of the solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample amount of 1.1 ml, cone rotor TE-1 (1 ° 34 ′, R24), and a temperature of 25 ° C.

[Molecular weight]
The molecular weight was measured by a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight (Mn and weight average molecular weight (Mw)) was calculated as a polyethylene glycol and polyethylene oxide equivalent value.
GPC apparatus: manufactured by Shodex (GPC-101), column: manufactured by Shodex (KD803, series of KD805), column temperature: 50 ° C., eluent: N, N-dimethylformamide (as an additive, lithium bromide-water) Japanese product (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L), flow rate: 1.0 ml / min

Standard sample for preparing calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (peak top manufactured by Polymer Laboratories) Molecular weight (Mp) about 12,000, 4,000, 1,000). In order to avoid the overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and three types of 150,000, 30,000, and 4,000. Two samples of the mixed sample were measured separately.

<Measurement of imidization ratio>
20 mg of polyimide powder was put into an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku)) and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixed product) (0.0. 53 ml) was added and completely dissolved by sonication. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNW-ECA500) (manufactured by JEOL Datum). The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid that appear in the vicinity of 9.5 ppm to 10.0 ppm. It calculated | required by the following formula | equation using the integrated value.
Imidization rate (%) = (1−α · x / y) × 100

In the above formula, x is a proton peak integrated value derived from NH group of amic acid, y is a peak integrated value of reference proton, α is one NH group proton of amic acid in the case of polyamic acid (imidation rate is 0%) Is the number ratio of the reference proton to.

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

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

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

Next, after the liquid crystal aligning agent is filtered through a 1.0 μm filter, spin coating is applied to the prepared substrate with electrodes and a glass substrate having a columnar spacer having a height of 4 μm on which an ITO film is formed on the back surface. It was applied by the method. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. This coating film surface was irradiated with linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 10: 1 or more via a polarizing plate. This substrate is immersed in at least one solvent selected from water and an organic solvent for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 to 300 ° C. for 5 minutes to provide a substrate with a liquid crystal alignment film Got. The two substrates are combined as a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is added. An empty cell was produced by curing. Liquid crystal MLC-3019 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

[Afterimage evaluation by long-term AC drive]
A liquid crystal cell having the same structure as the liquid crystal cell used for the above-described afterimage evaluation was prepared. Using this liquid crystal cell, an AC voltage of ± 5 V was applied for 120 hours at a frequency of 60 Hz in a constant temperature environment of 60 ° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, in the second pixel, the second region and the first region were compared to calculate a similar angle Δ.

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

[Evaluation of adhesion]
A sample for evaluation of adhesion was prepared as follows. A liquid crystal aligning agent was applied to a 30 mm × 40 mm ITO substrate by spin coating. After drying on an 80 ° C. hot plate for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a thickness of 100 nm. This coating surface was subjected to alignment treatment such as rubbing or irradiation with polarized ultraviolet rays to obtain a substrate with a liquid crystal alignment film. This substrate is immersed in at least one solvent selected from water and an organic solvent 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 provide a liquid crystal alignment film A substrate was obtained.

Two substrates thus obtained were prepared, and a 4 μm bead spacer was applied on the liquid crystal alignment film surface of one of the substrates, and then a sealing agent (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was dropped. Next, bonding was performed so that the liquid crystal alignment film surface of the other substrate was inside, and the overlapping width of the substrates was 1 cm. At that time, the amount of the sealant dropped was adjusted so that the diameter of the sealant after bonding was 3 mm. The two substrates bonded together were fixed with a clip and then thermally cured at 150 ° C. for 1 hour to prepare a sample for adhesion evaluation. After that, the sample substrate is fixed with the table top precision universal testing machine AGS-X500N manufactured by Shimadzu Corporation, and then the upper and lower substrate ends are fixed and then pressed from the upper center of the substrate to release the pressure (N) Was measured.

<Synthesis Example 1>
In a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 2.78 g (11.4 mmol) of DA-1, 3.50 g (15.2 mmol) of DA-2, and 3.89 g of DA-3 ( 11.4 mmol), 46.3 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 6.64 g (29.6 mmol) of CA-1 and 1.42 g (5.70 mmol) of CA-2 were added, and NMP was added to a solid content concentration of 18% by mass. 0.8 g was added and stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A) (viscosity: 850 mPa · s). The molecular weight of the polyamic acid was Mn = 15500 and Mw = 36500.

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

<Synthesis Example 13>
30 g of the polyamic acid solution (A) obtained in a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube was taken, 15.0 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 3.32 g of acetic anhydride and 0.43 g of pyridine were added and heated at 55 ° C. for 3 hours to perform chemical imidization. The obtained reaction liquid was poured into 213 ml of methanol while stirring, and the deposited precipitate was collected by filtration and subsequently washed with 213 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (A). The imidation ratio of this polyimide resin powder was 65%, and Mn = 6800 and Mw = 12000.

<Synthesis Examples 14 to 23>
Polyimide resin powders (B) to (K) shown in Table 2 below are used in the same manner as in Synthesis Example 13 except that the polyamic acid solution, NMP, acetic anhydride, pyridine, and methanol shown in Table 2 are used. )

<Synthesis Examples 24-28>
By using the diamine component, tetracarboxylic acid component, and NMP shown in Table 1-2 below, and carrying out in the same manner as in the reaction temperature, solid content concentration, and Synthesis Example 1, respectively, Acid solutions (M) to (Q) were obtained. Further, 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 carried out to obtain polyimide resin powders (M) to (M) shown in Table 2-2 below. Q) was obtained.

<Example 1>
Take 10.00 g of the 18% by mass polyamic acid solution (A) obtained in Synthesis Example 1 in a 100 ml Erlenmeyer flask, add 14.00 g of NMP and 6.00 g of BCS, and mix at 25 ° C. for 8 hours to obtain a liquid crystal aligning agent. (1) was obtained. This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Example 2>
Take 1.80 g of the polyimide resin powder (A) obtained in Synthesis Example 13 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP so that the solid content concentration becomes 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (K) was obtained. To this polyimide solution, 0.09 g of AD-1, 2.90 g of NMP, 9.00 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (2). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Examples 3 to 5>
Liquid crystal aligning agents (3) to (5) were obtained in the same manner as in Example 2, except that polyimide resin powders (B) to (D) were used instead of polyimide resin powder (A). .

<Example 6>
5. 50 g of the 15% by mass polyimide solution (D) obtained in Example 5 and 5.50 g of the 15% by mass polyamic acid solution (E) were placed in a 100 ml Erlenmeyer flask, 0.83 g of AD-1 and NMP were added. 4.82 g, 7.35 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (6). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Examples 7 to 8>
Liquid crystal aligning agents (7) to (8) were obtained in the same manner as in Example 2 except that polyimide resin powders (E) to (F) were used instead of polyimide resin powder (A). .

<Comparative Example 1>
The liquid crystal aligning agent (9) was obtained by implementing like Example 1 except having used the polyamic acid solution (H) instead of the polyamic acid solution (A).

<Comparative Examples 2 to 6>
Liquid crystal aligning agents (10) to (14) were obtained in the same manner as in Example 2 except that polyimide resin powders (G) to (K) were used instead of polyimide resin powder (A). .

<Example 9>
After the liquid crystal aligning agent (1) obtained in Example 1 is filtered through a 1.0 μm filter, the prepared substrate with electrodes and a columnar spacer with a height of 4 μm on which an ITO film is formed on the back surface are provided. It apply | coated to the glass substrate by the spin coat method. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 0.25 J / cm ² of linearly polarized ultraviolet light having a extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. This substrate is immersed in a mixed solution of pure water: 2-propanol = 1/1 for 3 minutes, then immersed in pure water for 1 minute, and dried on a hot plate at 230 ° C. for 14 minutes to obtain a substrate with a liquid crystal alignment film Got.

The above-mentioned two substrates obtained as a set were printed with a sealant on the substrate, and the other substrate was bonded so that the liquid crystal alignment film faced and the alignment direction was 0 °, The agent was cured to produce an empty cell. Liquid crystal MLC-3019 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and left to stand for evaluation of afterimages by long-term AC driving. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.20.

<Examples 10 to 16, Comparative Examples 7 to 12>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 3 was used, respectively, and the same as in Example 9 except that the ultraviolet irradiation amount and the immersion solution were changed to those shown in Table 3. The FFS drive liquid crystal cell was prepared by the method described above, and afterimage evaluation was performed by long-term alternating current drive. Table 3 shows the value of the angle Δ of the liquid crystal cell after long-term AC driving in each case.

<Example 17>
After the liquid crystal aligning agent (1) is filtered through a 1.0 μm filter, spin is applied to the prepared substrate with electrodes and a glass substrate having a columnar spacer with a height of 4 μm on which an ITO film is formed on the back surface. The coating method was applied. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 0.25 J / cm ² of linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 26: 1 through a polarizing plate, and then mixed with a pure water: 2-propanol = 1/1 mixed solution for 5 minutes. The substrate was then immersed for 14 minutes on a 230 ° C. hot plate immersed in pure water for 1 minute to obtain a substrate with a liquid crystal alignment film. It was 3H as a result of measuring this board | substrate with the pencil hardness test method (JIS K5400).

<Examples 18 to 25, Comparative Examples 13 to 18>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 4 was used, respectively, and the same as in Example 17 except that the ultraviolet irradiation amount and the immersion solution were changed to those shown in Table 4. Thus, samples for pencil hardness test were respectively prepared. Table 4 shows the results of evaluation of each pencil hardness test.

<Example 26>
The liquid crystal aligning 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 an 80 ° C. hot plate for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a thickness of 100 nm. Using a rubbing device with a roll diameter of 120 mm, the coating surface is rubbed with rayon cloth under conditions of a roll rotation speed of 300 rpm, a roll traveling speed of 20 mm / sec, and an indentation amount of 0.1 mm, and immersed in pure water for 1 minute. Then, it was ultrasonically cleaned and dried in a heat circulation oven at 80 ° C. to obtain a substrate with a liquid crystal alignment film.

Two substrates thus obtained were prepared, and a 4 μm bead spacer was applied on the liquid crystal alignment film surface of one of the substrates, and then a sealing agent (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was dropped. Next, bonding was performed so that the liquid crystal alignment film surface of the other substrate was inside, and the overlapping width of the substrates was 1 cm. At that time, the amount of the sealant dropped was adjusted so that the diameter of the sealant after bonding was 3 mm. The two substrates bonded together were fixed with a clip and then thermally cured at 150 ° C. for 1 hour to prepare a sample for adhesion evaluation. As a result of evaluating the adhesion, the strength at the time of peeling was 20N.

<Examples 27 to 33, Comparative Examples 19 to 24>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 5 was used, respectively, and the same as in Example 26, except that the ultraviolet ray irradiation amount and the immersion solution were changed to those shown in Table 5. A sample for adhesion evaluation was prepared by the method described above. Table 5 shows the results of the evaluation of adhesion.

<Example 34>
Take 1.80 g of the polyimide resin powder (M) obtained in Synthesis Example 29 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP so that the solid content concentration becomes 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (M) was obtained. To this polyimide solution, 0.09 g of AD-1, 2.90 g of NMP, 9.00 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (15). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Example 35>
A 100 ml Erlenmeyer flask was charged with 6.00 g of a 15% by weight polyimide solution (M) obtained in the same manner as in Example 34 and 6.00 g of the 15% by weight polyamic acid solution (N) obtained in Synthesis Example 25. 0.09 g of AD-1, 2.90 g of NMP, 9.00 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (16). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Example 36>
Take 1.80 g of the polyimide resin powder (O) obtained in Synthesis Example 30 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP to a solid content concentration of 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (O) was obtained. To this polyimide solution, 0.09 g of AD-1, 2.90 g of NMP, 9.00 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (17). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Example 37>
In a 100-ml Erlenmeyer flask, 6.00 g of a 15% by mass polyimide solution (O) obtained in the same manner as in Example 36 and 6.00 g of the 15% by mass polyamic acid solution (E) obtained in Synthesis Example 5 were taken. 0.09 g of AD-1, 2.90 g of NMP, 9.00 g of GBL and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (18). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormalities such as turbidity and precipitation.

<Examples 38 to 39>
Liquid crystal aligning agents (19) to (20) were obtained in the same manner as in Example 34, except that polyimide resin powders (Q) to (P) were used instead of polyimide resin powder (M). .

<Examples 40 to 45>
Example 9 was used except that the liquid crystal aligning agent shown in Table 3-2 was used instead of the liquid crystal aligning agent (1), and the ultraviolet irradiation amount and the immersion solution were other than those shown in Table 3-2. The FFS drive liquid crystal cell was manufactured by the same method as described above, and afterimage evaluation was performed by long-term alternating current drive. Table 3-2 shows the value of the angle Δ of the liquid crystal cell after the long-term AC driving in each case.

<Examples 46 to 51>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 4-2 was used, and the ultraviolet irradiation amount and immersion solution were changed to those shown in Table 4-2. Samples for pencil hardness test were prepared in the same manner as in Example 17. The results of evaluating each pencil hardness test are shown in Table 4-2.

<Examples 52 to 57>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 5-2 was used, and the irradiation amount of ultraviolet rays and the immersion solution were changed to those shown in Table 5-2. A sample for adhesion evaluation was produced in the same manner as in Example 26. The results of the evaluation of adhesion are shown in Table 5-2.

The liquid crystal aligning agent of the present invention can provide a liquid crystal aligning film having high film hardness and seal adhesion in addition to good afterimage characteristics. Therefore, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has a high yield in liquid crystal panel production, and can reduce afterimages due to alternating current driving generated in liquid crystal display elements of IPS driving method and FFS driving method, An IPS driving type or FFS driving type liquid crystal display element having excellent afterimage characteristics can be obtained. Therefore, it can be used in a liquid crystal display element that requires high display quality.

Claims

At least one selected from tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and at least one selected from tetracarboxylic dianhydrides represented by the following formula (2) and derivatives thereof. And a tetracarboxylic acid derivative component containing, a diamine component containing at least one diamine selected from the following formulas (3) and (4), and a polyimide precursor obtained from the polyimide that is an imidized product thereof A liquid crystal aligning agent comprising at least one selected polymer.

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

In the formula, each of R 3 to R 6 independently represents 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, or a fluorine atom. It is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, and 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, or a carbon containing a fluorine atom. These are monovalent organic groups having 1 to 6 or phenyl groups, which may be the same or different.

In the formula, 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, and A 2 is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol A nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms, a is an integer of 1 to 4, and when a is 2 or more, the structure of A 1 is the same or different. Also good. b and c are each independently an integer of 1 to 2.
2. The ratio of the tetracarboxylic dianhydride represented by the formula (2) or a derivative thereof is 1 to 30 mol% with respect to 1 mol of all tetracarboxylic derivative components. Liquid crystal aligning agent.
3. The liquid crystal aligning agent according to claim 1, wherein the structure of X 1 is at least one selected from the following formulas (X1-12) to (X1-16).
4. The liquid crystal aligning agent according to claim 1, wherein the structure of X 1 is the formula (X1-12).
5. The liquid crystal aligning agent according to claim 1, wherein the structure of X 2 is represented by the formula (X2-1).
The liquid crystal aligning agent according to any one of claims 1 to 5, wherein the diamine component contains at least one selected from the following formulas (DA-1) to (DA-20).
A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 6.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 7.
The liquid crystal display element according to claim 8, wherein the liquid crystal display element is for driving a liquid crystal by a horizontal electric field.