WO2013039168A1

WO2013039168A1 - Method for manufacturing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2013039168A1
Application number: PCT/JP2012/073515
Authority: WO
Inventors: 隆夫堀; 直樹作本
Original assignee: 日産化学工業株式会社
Priority date: 2011-09-15
Filing date: 2012-09-13
Publication date: 2013-03-21
Also published as: TW201326258A; JP6056759B2; CN103946738B; KR20140063795A; KR101951507B1; CN103946738A; JPWO2013039168A1; TWI551625B

Abstract

Provided is a method for manufacturing a liquid crystal alignment film whereby anisotropy is increased and unevenness caused by processing can be suppressed. A film obtained by applying a liquid crystal alignment agent containing at least one type of polymer selected from the group consisting of a polyimide and a precursor of the polyimide on a substrate and firing the product is irradiated with polarized radiation, then treated by contact with a solution containing at least one type of organic solvent selected from the group consisting of formula (A-1), formula (A-2), formula (A-3), formula (A-4), and formula (A-5). (In the formulas, A₁ represents a hydrogen atom or an acetyl group, A₂ represents a C_1-6 alkyl group, R₂ represents a hydrogen atom or a methyl group, n represents 1 or 2, A₃ represents a C_1-4 alkyl group, R₃ and R₄ represent a hydrogen atom or a methyl group, A₅ and A₆ represent a C_1-4 alkyl group, and A₆ represents a C_3-6 alkyl group or cycloalkyl group.)

Description

Method for producing liquid crystal alignment film, liquid crystal alignment film, and liquid crystal display element

The present invention relates to a method for producing a liquid crystal alignment film for a photo-alignment method, a liquid crystal alignment film obtained by this production method, and a liquid crystal display device comprising the obtained liquid crystal alignment film.

In a liquid crystal display element used for a liquid crystal television, a liquid crystal display, and the like, a liquid crystal alignment film for controlling the alignment state of liquid crystals is usually provided in the element.
Currently, the most widely used liquid crystal alignment film in the industry is made of a polyamic acid formed on an electrode substrate and / or a polyimide film obtained by imidizing the same with a cloth such as cotton, nylon or polyester. It is manufactured by performing a so-called rubbing process that rubs in the 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 method for replacing the rubbing treatment, a photo-alignment method for imparting 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 photolysis reaction, and the like have been proposed (see Non-Patent Document 1).
On the other hand, when polyimide is used for the liquid crystal alignment film for photo-alignment, its usefulness is expected because it has higher heat resistance than others.
Patent Document 1 proposes that a polyimide film having an alicyclic structure such as a cyclobutane ring in the main chain is used for the photo-alignment method.

However, the liquid crystal alignment film obtained by the photo-alignment method has a problem that anisotropy with respect to the alignment direction of the polymer liquid crystal alignment film is smaller than that by rubbing. If the anisotropy is small, sufficient liquid crystal orientation cannot be obtained, and when a liquid crystal display element is formed, there is a problem that an afterimage is generated. As a method for increasing the anisotropy of a liquid crystal alignment film obtained by a photo-alignment method, it has been proposed to remove a low molecular weight component generated by cutting the polyimide main chain by light irradiation after light irradiation (Patent Literature). 2).

Japanese Unexamined Patent Publication No. 9-297313 Japanese Unexamined Patent Publication No. 2011-107266

As a result of investigations by the inventors of the present application, after irradiating a polarized radiation to a polyimide film obtained by applying and baking a polyimide film or a polyimide precursor, a treatment such as immersion in water or an organic solvent is performed. It was confirmed that the anisotropy of the obtained liquid crystal alignment film was increased. However, it has been found that when these treatments are performed, problems such as unevenness occur in the obtained liquid crystal alignment film, and the characteristics of the liquid crystal alignment film are greatly impaired.

The object of the present invention is to increase the anisotropy of the liquid crystal alignment film obtained by the photo-alignment method, and to suppress the unevenness that occurs during the process, and the method of manufacturing the liquid crystal alignment film And a liquid crystal display element comprising the liquid crystal alignment film obtained by the method for producing the liquid crystal alignment film.

As a result of intensive studies to achieve the above-mentioned object, the present inventors irradiate a film obtained by applying and baking a polyimide film or a polyimide precursor with polarized radiation, By performing contact treatment such as immersion using a solution containing an organic solvent, the anisotropy of the obtained liquid crystal alignment film can be remarkably improved, and the above-described problem of unevenness occurring in the liquid crystal alignment film can be solved. I found it.

Thus, the present invention has the following gist.
1. Polarized radiation on an imidized film obtained by applying and baking a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of the polyimide and an organic solvent on a substrate And then at least selected from the group consisting of the following formula (A-1), formula (A-2), formula (A-3), formula (A-4), and formula (A-5) A method for producing a liquid crystal alignment film, wherein the contact treatment is performed with a solution containing one kind of organic solvent.

(In Formula (A-1), A ₁ is a hydrogen atom or an acetyl group, A ₂ is an alkyl group having 1 to 6 carbon atoms, R ₂ is a hydrogen atom or a methyl group, and n is 1 or 2 In formula (A-2), A ₃ is an alkyl group having 1 to 4 carbon atoms, and in formula (A-3), R ₃ and R ₄ are each independently a hydrogen atom or In formula (A-4), A ₅ and A ₆ each independently represents an alkyl group having 1 to 4 carbon atoms, and in formula (A-5), A ₆ represents 3 carbon atoms. 6 to 6 alkyl groups or cycloalkyl groups.)
2. 2. The method for producing a liquid crystal alignment film according to 1 above, wherein the organic solvent has a boiling point of 100 to 180 ° C.
3. 3. The method for producing a liquid crystal alignment film according to 1 or 2, wherein the organic solvent is 1-methoxy-2-propanol, ethyl lactate, diacetone alcohol, methyl 3-methoxypropionate, or ethyl 3-ethoxypropionate.

4). The above 1-3, wherein the polymer contains at least one polymer selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (3) and an imidized polymer of the polyimide precursor. The manufacturing method of the liquid crystal aligning film in any one of.

(In the formula (3), X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9), and Y ₁ is a divalent organic group. R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(In Formula (X1-1), R ₃ , R ₄ , R ₅ , and R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. Group, alkenyl group, or phenyl group.)
5. From the group consisting of a polyimide precursor in which the polymer contains 60 mol% or more of the structural unit represented by the formula (3) with respect to 1 mol of the whole polymer, and an imidized polymer of the polyimide precursor. 5. The method for producing a liquid crystal alignment film as described in 4 above, which is at least one selected.
6). 5. The method for producing a liquid crystal alignment film according to 4, wherein in the formula (3), X ₁ is represented by the formula (X1-1).
7). 5. The method for producing a liquid crystal alignment film according to 4 above, wherein, in the formula (3), X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-10) to (X1-11): .

8). 5. The method for producing a liquid crystal alignment film according to 4, wherein in the formula (3), Y ₁ is at least one selected from the group consisting of structures represented by the following formulas (4) and (5).

(In Formula (5), Z ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.)
9. 9. The method for producing a liquid crystal alignment film according to 8, wherein in the formula (3), Y ₁ is a structure represented by the formula (4).

10. A liquid crystal obtained by irradiating a film obtained by applying and baking a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of the polyimide on a base plate, with polarized radiation. A contact treatment solution for an alignment film, which is selected from the group consisting of Formula (A-1), Formula (A-2), Formula (A-3), Formula (A-4), and Formula (A-5). A contact treatment liquid for a liquid crystal alignment film comprising a solution containing at least one organic solvent.
11. 10. A liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to any one of 1 to 9 above.
12 12. A liquid crystal display device comprising the liquid crystal alignment film as described in 11 above.

According to the method for producing a liquid crystal alignment film of the present invention, a liquid crystal alignment film having a high anisotropy subjected to alignment treatment by a photo-alignment method is obtained, and at the same time, the obtained liquid crystal alignment film is a uniform film without film unevenness. can get.
Thus, the liquid crystal alignment film according to the production method of the present invention has a high anisotropy and thus has a high liquid crystal alignment regulating force, an excellent afterimage characteristic, and a high-quality liquid crystal display element when used in a liquid crystal display element.

The effect of improving the above-mentioned anisotropy achieved by the method for producing a liquid crystal alignment film of the present invention and the effect of suppressing the occurrence of film unevenness during processing are shown in comparison with Examples and Comparative Examples described later. As is apparent from 1 ", there are significant differences depending on the solvent used.
That is, as seen in “Table 1” to be described later, when water, isopropyl alcohol, or the like is used as a solvent, the improvement in anisotropy of the obtained liquid crystal alignment film is hardly observed, and at the same time, these solvents are used. When is used, unevenness occurs in the obtained liquid crystal alignment film.
However, when the contact treatment is performed with a solution containing at least one organic solvent selected from the group consisting of the compounds represented by the above formulas (A-1) to (A-5) in the present invention, the liquid crystal alignment film The improvement in the anisotropy is greatly improved, and at the same time, the occurrence of unevenness in the obtained liquid crystal alignment film can be remarkably suppressed.

<Polyimide and precursor of the polyimide>
In the present invention, at least one polymer selected from the group consisting of a polyimide to which anisotropy is imparted by irradiation with polarized radiation and a precursor of the polyimide (hereinafter also simply referred to as a polymer). ) Is used. If it is the polyimide or polyimide precursor which satisfy | fills this condition, the structure will not be specifically limited.
If a specific example is given, since the obtained liquid crystal aligning film has high anisotropy, as a polymer used for this invention, the polyimide precursor which has a structural unit represented by following formula (3), and this polyimide Precursor imidized polymers are preferred. From the viewpoint of solubility in an organic solvent, a polyimide precursor having a structural unit represented by the following formula (3) is particularly preferable.

In the formula (3), R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. From the viewpoint of ease of imidization by heating, a hydrogen atom or a methyl group is particularly preferable.

X ₁ is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9).

In the formula (X1-1), R ₃ , R ₄ , R ₅ , and R ₆ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. , An alkenyl group or a phenyl group, which may be the same or different. From the viewpoint of liquid crystal orientation, R ₃ , R ₄ , R ₅ , and R ₆ are each independently preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. . X ₁ is more preferably at least one selected from the group consisting of structures represented by the following formulas (X1-10) and (X1-11).

Y ₁ is a divalent organic group, and its structure is not particularly limited. Since the obtained liquid crystal alignment film has high anisotropy, it is preferably at least one selected from the group consisting of structures represented by the following formulas (Y1-1) and (Y1-2).

In Formula (5), Z ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.
In Z ₁ , the ester bond is represented by —C (O) O— or —OC (O) —. As the amide bond, a structure represented by —C (O) NH—, —C (O) NR—, —NHC (O) —, or —NRC (O) — can be shown. R is an alkyl group, alkenyl group, alkynyl group, aryl group, or a combination thereof having 1 to 10 carbon atoms.

Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, and a bicyclohexyl group. Examples of the alkenyl group include those in which one or more CH ₂ —CH ₂ structures present in the above alkyl group are replaced with a CH═CH structure, and more specifically, vinyl groups, allyl groups, 1- Examples include propenyl group, isopropenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, 2-hexenyl group, cyclopropenyl group, cyclopentenyl group, cyclohexenyl group and the like. Alkynyl groups include those in which one or more CH ₂ —CH ₂ structures present in the alkyl group are replaced with C≡C structures, and more specifically, ethynyl groups, 1-propynyl groups, 2 -Propynyl group and the like. Examples of the aryl group include a phenyl group.

As the thioester bond, a structure represented by —C (O) S— or —SC (O) — can be shown.
When Z ₁ is an organic group having 2 to 10 carbon atoms, it can be represented by the structure of the following formula (6).

In the formula (6), Z ₄ , Z ₅ , and Z ₆ are each independently a single bond, —O—, —S—, —NR ₁₁ —, an ester bond, an amide bond, a thioester bond, a urea bond, It is a carbonate bond or a carbamate bond. R ₁₁ is a hydrogen atom, a methyl group, or a t-butoxycarbonyl group.
The ester bond, amide bond, and thioester bond in Z ₄ , Z ₅ , and Z ₆ can have the same structure as the ester bond, amide bond, and thioester bond described above.

As the urea bond, a structure represented by —NH—C (O) NH— or —NR—C (O) NR— can be shown. R is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a combination thereof having 1 to 10 carbon atoms, and these groups are the same examples as the above-mentioned alkyl group, alkenyl group, alkynyl group, and aryl group. Can be mentioned.
As the carbonate bond, a structure represented by —O—C (O) —O— can be shown.
The carbamate bond is —NH—C (O) —O—, —O—C (O) —NH—, —NR—C (O) —O—, or —O—C (O) —NR—. The structure represented can be shown. R is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a combination thereof having 1 to 10 carbon atoms, and these groups are the same examples as the above-mentioned alkyl group, alkenyl group, alkynyl group, and aryl group. Can be mentioned.

R ₉ and R ₁₀ in the formula (6) are each independently a structure selected from a single bond, an alkylene group having 1 to 10 carbon atoms, an alkenylene group, an alkynylene group, an arylene group, or a combination thereof. . When any of R ₉ and R ₁₀ is a single bond, either R ₉ or R ₁₀ is an alkylene group, an alkenylene group, an alkynylene group, an arylene group, or a combination thereof having 2 to 10 carbon atoms. The structure to be selected.
As said alkylene group, the structure remove | excluding one hydrogen atom from the said alkyl group is mentioned. More specifically, a methylene group, 1,1-ethylene group, 1,2-ethylene group, 1,2-propylene group, 1,3-propylene group, 1,4-butylene group, 1,2-butylene group 1,2-pentylene group, 1,2-hexylene group, 2,3-butylene group, 2,4-pentylene group, 1,2-cyclopropylene group, 1,2-cyclobutylene group, 1,3- A cyclobutylene group, a 1,2-cyclopentylene group, a 1,2-cyclohexylene group and the like can be mentioned.

The alkenylene group includes a structure in which one hydrogen atom is removed from the alkenyl group. More specifically, 1,1-ethenylene group, 1,2-ethenylene group, 1,2-ethenylenemethylene group, 1-methyl-1,2-ethenylene group, 1,2-ethenylene-1,1- Ethylene group, 1,2-ethenylene-1,2-ethylene group, 1,2-ethenylene-1,2-propylene group, 1,2-ethenylene-1,3-propylene group, 1,2-ethenylene-1, Examples include 4-butylene group and 1,2-ethenylene-1,2-butylene group.
The alkynylene group includes a structure in which one hydrogen atom is removed from the alkynyl group. More specifically, an ethynylene group, an ethynylene methylene group, an ethynylene-1,1-ethylene group, an ethynylene-1,2-ethylene group, an ethynylene-1,2-propylene group, an ethynylene-1,3-propylene group, Examples include ethynylene-1,4-butylene group, ethynylene-1,2-butylene group and the like.

The arylene group includes a structure in which one hydrogen atom is removed from the aryl group. More specific examples include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group and the like.
If the linearity contains a high structural and rigid structure to Y _1, since the liquid crystal alignment film having good liquid crystal alignment property can be obtained, as the structure of Z _1, a single bond, or the following formula (A1-1) The structure of (A15-25) is more preferable.

As the Y ₁ structure is more rigid, a liquid crystal alignment film having excellent liquid crystal alignment is obtained. Therefore, the structure represented by the above formula (4) is particularly preferable as the Y ₁ structure.
In the polyimide precursor containing the structural unit represented by the above formula (3) and the imidized polymer of the polyimide precursor, the ratio of the structural unit represented by the above formula (3) is the total of all the polymers. 60 to 100 mol% is preferable with respect to 1 mol of the structural unit. The higher the ratio of the structural unit represented by the above formula (3), the better the liquid crystal alignment film having good liquid crystal alignment, so 80-100 mol% is more preferable, and 90-100 mol% is more preferable.

In addition to the structural unit represented by the above formula (3), the polymer component of the present invention may be a polyimide precursor containing a structural unit represented by the following formula (7) and the polyimide precursor.

In the formula (7), _{R 1} is the same as defined for _{R 1} in the formula (3).

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-42). From the viewpoint of availability of the compound, the structure of X ₃ is preferably X-17, X-25, X-26, X-27, X-28, X-32, or X-39. Further, from the viewpoint of alleviation of the accumulated residual charge obtained fast liquid crystal alignment film by a DC voltage, it is preferable to use a tetracarboxylic dianhydride having an aromatic ring structure, the structure of X ₃ is, X -26, X-27, X-28, X-32, X-35, or X-37 are more preferred.

In the above formula (7), Y ₄ is a divalent organic group, and its structure is not particularly limited. Specific examples of Y ₄ include structures of the following formulas (Y-1) to (Y-74).

Y ₄ in the formula (7) is Y-8, Y-20, Y-21, Y-22, Y-28, Y-29, Y- in order to improve the solubility of the polymer component in the organic solvent. It is preferable to contain a structural unit having a structure of 30, Y-72, Y-73, or Y-74.
When the ratio of the structural unit represented by the above formula (7) in the polymer component is high, the ratio of the structural unit represented by the above formula (7) is the total structure in order to reduce the liquid crystal orientation of the liquid crystal alignment film. The amount is preferably 0 to 40 mol%, more preferably 0 to 20 mol%, based on 1 mol of the unit.

<Method for producing polyamic acid ester>
The polyamic acid ester which is a polyimide precursor used in the present invention can be synthesized by the following methods (1) to (3).
(1) When synthesizing from polyamic acid The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.
Specifically, the polyamic acid and the esterifying agent are synthesized by reacting them 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.

As the esterifying agent, those that can be easily removed by purification are preferable. 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, 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 contamination of the 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 times by mole, more preferably 2 to 2.5 times by mole with respect 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 times mol, more preferably 2 to 3 times mol with respect 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 0.1 to 5 times mol, more preferably 2 to 3 times mol for the diamine component.

Among the three polyamic acid ester synthesis methods, a high molecular weight polyamic acid ester is obtained, and thus 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 the polymer by pouring into the 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 imidization in which a basic catalyst is added to the polyamic acid solution obtained by dissolving the polyamic acid ester solution or 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 hardly lowered 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 catalyst amount, temperature, and reaction time.
When manufacturing a polyimide from a polyamic acid, the chemical imidation which adds a catalyst to the solution of the said polyamic acid obtained by 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 preferred 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 thoroughly stirring. 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 depending on the thickness of the coating film to be formed. % 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 used for this invention will not be specifically limited if a polymer component melt | dissolves uniformly. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, Examples include 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 used for this invention may contain the solvent for improving the coating-film uniformity at the time of apply | coating a liquid crystal aligning agent to a board | substrate other than the organic solvent for dissolving a polymer component. . As such a solvent, a solvent having a surface tension lower than that of the organic solvent is generally used. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and 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, lactate isoa Glycol ester and the like. Two or more of these solvents may be used in combination.

In the liquid crystal aligning agent of the present invention, in addition to the above, the purpose is to change the electrical properties such as the dielectric constant and conductivity of the polymer other than the polymer and the liquid crystal aligning film as long as the effects of the present invention are not impaired. A dielectric or conductive material, a silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, a crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film, and a coating. When firing the film, an imidization accelerator for the purpose of efficiently imidizing the polyamic acid may be added.

<Method for producing liquid crystal alignment film>
The method for producing a liquid crystal alignment film of the present invention comprises a step of applying a liquid crystal aligning agent to a substrate and baking, a step of irradiating the obtained film with polarized radiation, and contacting the irradiated film with a specific solvent. A step of processing.

(1) The process of apply | coating a liquid crystal aligning agent to a board | substrate, and baking The liquid crystal aligning agent obtained as mentioned above was apply | coated to the board | substrate, it dried and baked, and the polyimide film or the polyimide precursor was imidated. A membrane is obtained.
The substrate to which the liquid crystal aligning agent used in the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. From the viewpoint of simplification of the process, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed. 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. In this case, a material that reflects light such as aluminum can be used. Examples of the method for applying the liquid crystal aligning agent used in the present invention include a spin coating method, a printing method, and an ink jet method.

The drying and baking steps after applying the liquid crystal aligning agent can be selected at any temperature and time. Usually, in order to sufficiently remove the organic solvent contained, it is dried at 50 to 120 ° C., preferably 60 to 100 ° C. for 1 to 10 minutes, and then 150 to 300 ° C., preferably 200 to 250 at 5 to 120. It is fired in minutes. The thickness of the coating film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered, and therefore it is 5 to 300 nm, preferably 10 to 200 nm.

(2) A step of irradiating the obtained film with polarized radiation The film obtained by the method of (1) above is irradiated with polarized radiation (hereinafter also referred to as photo-alignment treatment), thereby polarizing the film. Anisotropy is imparted in the direction perpendicular to the direction.
As a specific example of the photo-alignment treatment, there is a method in which the surface of the coating film is irradiated with radiation polarized in a certain direction, and in some cases, a heat treatment is further performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. Can be mentioned. As the wavelength of radiation, ultraviolet rays and visible rays having a wavelength of 100 to 800 nm can be used. Of these, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and those having a wavelength of 200 to 400 nm are particularly preferable.
Dose of the radiation is preferably in the range of 1 ~ 10,000mJ / cm ^2, and particularly preferably in the range of 100 ~ 5,000mJ / cm ^2.

(3) The process of contact-treating the film irradiated with radiation with a solution containing an organic solvent In the above, the film irradiated with polarized radiation is then contact-treated with a solution containing a specific organic solvent. The organic solvent used here is selected from the group consisting of the following (A-1), formula (A-2), formula (A-3), formula (A-4), and formula (A-5). At least one organic solvent or organic solvent.

In the formula (A-1), A ₁ is a hydrogen atom or an acetyl group, A ₂ is an alkyl group having 1 to 6 carbon atoms, R ₂ is a hydrogen atom or a methyl group, and n is 1 or 2 Is an integer.
In the formula (A-2), A ₃ is an alkyl group having 1 to 4 carbon atoms.
In the formula (A-3), R ₃ and R ₄ are each independently a hydrogen atom or a methyl group.
In formula (A-4), A ₅ and A ₆ are each independently an alkyl group having 1 to 4 carbon atoms.
In the formula (A-5), A ₆ is an alkyl group or cycloalkyl group having 3 to 6 carbon atoms.

The organic solvents of the above formulas (A-1) to (A-5) are preferably water-soluble having a boiling point of preferably 100 to 180 ° C., more preferably 110 to 160 ° C. If the boiling point is high, it will remain in the film and adversely affect the properties of the liquid crystal alignment film. On the other hand, if the boiling point is low, the film tends to volatilize, which tends to cause unevenness in the film. .
The organic solvents represented by the above formulas (A-1) to (A-5) have high anisotropy and are easy to obtain a uniform liquid crystal alignment film. Therefore, 1-methoxy-2-propanol, 1- At least one selected from the group consisting of methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate Species are preferred. In particular, at least one selected from the group consisting of 1-methoxy-2-propanol and ethyl lactate is preferable.

The solution containing the organic solvent used for the contact treatment may contain other solvents or solvents other than the organic solvents represented by the above formulas (A-1) to (A-5) as long as the effects of the present invention are not impaired. Examples of other solvents include, but are not limited to, water, methanol, ethanol, 2-propanol, acetone, and methyl ethyl ketone. In particular, water is more preferable from the viewpoints of versatility and safety.
Even when the other solvent is contained, the content of the at least one organic solvent selected from the group consisting of the above formulas (A-1) to (A-5) is the amount of the solution used for the contact treatment. The amount is preferably 10 to 100% by mass, more preferably 30 to 100% by mass, and particularly preferably 50 to 100% by mass with respect to the total amount.

In the present invention, the contact treatment between the film irradiated with polarized radiation and the solution containing the organic solvent is a treatment such that the film and the liquid are preferably in sufficient contact with each other, such as immersion treatment or spraying treatment. Done. Among them, a method of immersing the film in a solution containing an organic solvent, preferably 10 seconds to 1 hour, more preferably 1 to 30 minutes is preferable. The contact treatment may be performed at room temperature or preferably at 10 to 80 ° C., more preferably 20 to 50 ° C. Moreover, a means for enhancing contact such as ultrasonic waves can be applied as necessary.
After the above contact treatment, for the purpose of removing the organic solvent in the used solution, either rinsing or rinsing with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or both are used. May be done. The temperature for drying is preferably from 80 to 250 ° C, more preferably from 80 to 150 ° C.

<Liquid crystal display element>
The liquid crystal display element of the present invention is a liquid crystal cell obtained by a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent obtained by the production method of the present invention, and using the liquid crystal cell. It is a liquid crystal display element.
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. Note that an active matrix liquid crystal display element 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.

First, 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 film made of SiO ₂ —TiO ₂ formed by a sol-gel method.
Next, the liquid crystal alignment film of the present invention is formed on each substrate.
Next, the other substrate is superposed on one substrate so that the alignment film surfaces face each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealing material. In addition, it is preferable to spray spacers for controlling the substrate gap on the in-plane portion where no sealing material is provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.

Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing material through the opening provided in the sealing material. Thereafter, 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. 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. By passing through the above process, the liquid crystal display element of this invention is obtained. Since this liquid crystal display element uses the liquid crystal alignment film obtained by the liquid crystal alignment film manufacturing method of the present invention as the liquid crystal alignment film, the liquid crystal display element has excellent afterimage characteristics, and has a large screen and a high-definition liquid crystal television. It can use suitably for.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
The abbreviations of the compounds used in Examples and Comparative Examples, and the measuring methods of each property are as follows.
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve IPA: 2-propanol PGMEA: 1-methoxy-2-propanol acetate PG: propylene glycol MMP: methyl-3-methoxypropionate DE-1: The following formula (DE-1)
DA-1: Formula (DA-1) below
DA-2: Formula (DA-2) below
DA-3: Formula (DA-3) below
Additive A: N-α- (9-fluorenylmethoxycarbonyl) -N-τ-t-butoxycarbonyl-L-histidine

Hereinafter, methods for evaluating molecular weight, anisotropy of the alignment film, and film unevenness will be described.
[Molecular weight]
The molecular weight of the polyamic acid ester was measured by a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) were calculated as polyethylene glycol and polyethylene oxide equivalent values.
GPC device: manufactured by Shodex (GPC-101)
Column: manufactured by Shodex (series of KD803 and KD805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as additives, lithium bromide-hydrate (LiBr · H ₂ O) is 30 mmol / L (liter), phosphoric acid / anhydrous crystal (o-phosphoric acid) is 30 mmol / L, tetrahydrofuran (THF) is 10 ml / L)
Flow rate: 1.0 ml / min Standard sample for preparing a calibration curve: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polymer laboratory Polyethylene glycol manufactured by the company (peak top molecular weight (Mp) of 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. Separately performed on two of the mixed samples.

[Anisotropy of alignment film]
The anisotropy of the alignment film was measured as follows.
Measurement was performed using an ultraviolet-visible-near infrared spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation. The degree of anisotropy was measured from the absorbance (value of 235 nm) with respect to the alignment direction of the obtained alignment film and the absorbance with respect to the direction perpendicular to the alignment direction.

[Membrane unevenness]
For the evaluation of film unevenness, the film-coated substrate after the immersion treatment was visually observed and classified as follows.
○: No unevenness △: Some unevenness was observed ×: Large unevenness or whitening was observed

<Synthesis Example 1>
A 500 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 4.58 g (42.4 mmol) of p-phenylenediamine was added, and 1.79 g (4.71 mmol) of DA-1 was added. 84.7 g, 254 g of GBL, and 8.40 g (106 mmol) of pyridine as a base were added and dissolved by stirring. Next, while stirring this diamine solution, 14.4 g (44.2 mmol) of DE-1 was added and reacted at 15 ° C. overnight. After stirring overnight, 1.23 g (13.6 mmol) of acryloyl chloride was added and reacted at 15 ° C. for 4 hours. The obtained polyamic acid ester solution was added to 1477 g of IPA with stirring, and the precipitated white precipitate was collected by filtration, then washed 5 times with 738 g of IPA and dried to give a white polyamic acid ester. 17.3 g of resin powder was obtained. The yield was 96.9%. Moreover, the molecular weight of this polyamic acid ester was Mn = 14,288 and Mw = 29,956.
3.69 g of the obtained polyamic acid ester resin powder was placed in a 100 mL Erlenmeyer flask, 33.2 g of GBL was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution.

<Synthesis Example 2>
Into a 20 mL sample tube containing a stir bar, 5.26 g of the polyamic acid ester solution obtained in Synthesis Example 1 was taken, 3.16 g of GBL, 2.11 g of BCS, and 0.19 g of additive A were added, The liquid crystal aligning agent A was obtained by stirring for 30 minutes with a tic stirrer.

<Synthesis Example 3>
A 500 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, and 2.50 g (23.1 mmol) of p-phenylenediamine was added, and 0.59 g (1.22 mmol) of DA-2 was added. 42.8 g, 129 g of GBL, and 4.34 g (54.9 mmol) of pyridine as a base were added and dissolved by stirring. Next, while stirring this diamine solution, 7.44 g (22.9 mmol) of DE-1 was added and reacted at 15 ° C. overnight. After stirring overnight, 0.63 g (7.01 mmol) of acryloyl chloride was added and reacted at 15 ° C. for 4 hours. The obtained polyamic acid ester solution was added to 574 g of IPA with stirring, and the precipitated white precipitate was collected by filtration, then washed with 382 g of IPA five times and dried to give a white polyamic acid ester resin. 8.82 g of powder was obtained. The yield was 97.8%. Moreover, the molecular weight of this polyamic acid ester was Mn = 16617 and Mw = 37387.
0.80 g of the obtained polyamic acid ester resin powder was placed in a 100 mL Erlenmeyer flask, 7.20 g of GBL was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution.

<Synthesis Example 4>
To a 20 mL sample tube containing a stirrer, 8.00 g of the polyamic acid ester solution obtained in Synthesis Example 3 was taken, 8.01 g of GBL, 4.00 g of BCS, and 0.28 g of additive A were added, The liquid crystal aligning agent B was obtained by stirring with a magnetic stirrer for 30 minutes.

<Synthesis Example 5>
The inside of a 500 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 1.23 g (11.3 mmol) of p-phenylenediamine was added, and 0.80 g ( 3.77 mmol), 27.0 g of NMP, 91.2 g of GBL, and 2.69 g (34.0 mmol) of pyridine as a base were added and dissolved by stirring. Next, while stirring this diamine solution, 4.61 g (14.2 mmol) of DE-1 was added and reacted at 15 ° C. overnight. After stirring overnight, 0.39 g (4.34 mmol) of acryloyl chloride was added and reacted at 15 ° C. for 4 hours. The obtained polyamic acid ester solution was added to 384 g of IPA with stirring, and the precipitated white precipitate was collected by filtration, then washed with 256 g of IPA five times, and dried to give a white polyamic acid ester resin. 5.11 g of powder was obtained. The yield was 89.6%. Moreover, the molecular weight of this polyamic acid ester was Mn = 14806 and Mw = 32719.
0.80 g of the obtained polyamic acid ester resin powder was placed in a 100 mL Erlenmeyer flask, 7.20 g of GBL was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution.

<Synthesis Example 6>
To a 20 mL sample tube containing a stir bar, 8.01 g of the polyamic acid ester solution obtained in Synthesis Example 5 was taken, 8.01 g of GBL, 4.00 g of BCS, and 0.28 g of additive A were added, The liquid crystal aligning agent C was obtained by stirring for 30 minutes with a magnetic stirrer.

<Synthesis Example 7>
A 500 mL four-necked flask equipped with a stirrer was placed in a nitrogen atmosphere, 2.80 g (25.9 mmol) of p-phenylenediamine was added, and 1.45 g (6.47 mmol) of DA-3 was added. 111 g and 6.18 g (78.1 mmol) of pyridine as a base were added and dissolved by stirring. Next, 9.89 g (30.4 mmol) of DE-1 was added while stirring the diamine solution, and the mixture was reacted at 15 ° C. overnight. After stirring overnight, 0.38 g (4.21 mmol) of acryloyl chloride was added and reacted at 15 ° C. for 4 hours. The obtained polyamic acid ester solution was added to 1230 g of water while stirring, and the precipitated white precipitate was collected by filtration, then washed 5 times with 1230 g of IPA and dried to give a white polyamic acid ester resin. 10.2 g of powder was obtained. The yield was 83.0%. Moreover, the molecular weight of this polyamic acid ester was Mn = 20,786 and Mw = 40,973.
0.798 g of the obtained polyamic acid ester resin powder was put into a 100 mL Erlenmeyer flask, 7.18 g of GBL was added, and the mixture was stirred and dissolved at room temperature for 24 hours to obtain a polyamic acid ester solution.

<Synthesis Example 8>
Into a 20 mL sample tube containing a stir bar, 7.98 g of the polyamic acid ester solution obtained in Synthesis Example 7 was taken, 8.03 g of GBL, 4.00 g of BCS, and 0.28 g of additive A were added, The liquid crystal aligning agent D was obtained by stirring for 30 minutes with a magnetic stirrer.

<Synthesis Example 9>
In a 300 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 46.0 g (0.43 mol) of p-phenylenediamine, 17.8 g (0.075 mol) of DA-3, and 1389 g of NMP were placed. Stir to dissolve. While stirring this solution, 107 g (0.48 mol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further adjusted to 10% by mass. NMP was added and stirred at room temperature for 24 hours to obtain a solution of polyamic acid (PAA-1). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 215 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 1629 and Mw = 29521.

<Synthesis Example 10>
In a 50 ml sample tube containing a stir bar, 11.0 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 9, 5.00 g of NMP, 4.01 g of BCS, and 0.15 g of additive A are taken. The liquid crystal aligning agent E was obtained by stirring with a magnetic stirrer for 30 minutes.

<Synthesis Example 11>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 4.25 g (20.0 mmol) of 4,4′-diamino-1,2-diphenylethane was taken, 70.9 g of NMP was added, and nitrogen was added. The mixture was stirred and dissolved while feeding. While stirring this diamine solution, 3.82 g (19.5 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and NMP was further added so that the solid concentration was 10% by mass. The mixture was stirred at room temperature for 24 hours to obtain a polyamic acid (PAA-2) solution. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 156 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 13966 and Mw = 33163.

<Synthesis Example 12>
Into a 20 ml sample tube containing a stir bar, 12.2 g of the polyamic acid solution (PAA-2) obtained in Synthesis Example 11 was taken, 5.12 g of NMP and 2.90 g of BCS were added, and a magnetic stirrer was added. The liquid crystal aligning agent F was obtained by stirring for 30 minutes.

<Synthesis Example 13>
Into a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, take 5.17 g (20.0 mmol) of 1,3-bis (4-aminophenoxy) propane, add 72.0 g of NMP, and send nitrogen. While stirring, the mixture was dissolved. While stirring the diamine solution, 3.79 g (19.3 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and NMP was further added so that the solid content concentration was 10% by mass. The mixture was stirred at room temperature for 24 hours to obtain a polyamic acid (PAA-3) solution. The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 162 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 25902 and Mw = 40413.

<Synthesis Example 14>
Into a 20 ml sample tube containing a stir bar, 11.9 g of the polyamic acid solution (PAA-3) obtained in Synthesis Example 13 was taken, 3.98 g of NMP and 3.97 g of BCS were added, and a magnetic stirrer was added. The liquid crystal aligning agent G was obtained by stirring for 30 minutes.

<Example 1>
The liquid crystal aligning agent A obtained in Synthesis Example 2 was filtered through a 1.0 μm filter, spin-coated on a glass substrate, dried on a hot plate at a temperature of 80 ° C. for 3 minutes, and then baked at 230 ° C. for 10 minutes. A polyimide film having a thickness of 100 nm was obtained. The coating surface was irradiated with 254 nm ultraviolet light through a polarizing plate at 1.2 J / cm ² .
Next, the film-coated substrate obtained above was immersed in PGME (boiling point: 120 ° C.) at 25 ° C. for 3 minutes, rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes. Thus, a liquid crystal alignment film was obtained. As a result of measuring the anisotropy with respect to the alignment direction of the obtained liquid crystal alignment film, the magnitude of the anisotropy was 1.84. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 2>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a polyimide substrate coated, dried and baked on a substrate was irradiated with ultraviolet rays to form a substrate with a film PGMEA ( (Boiling point: 146 ° C.) at 25 ° C. for 3 minutes, rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.51. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 3>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating a polyimide film coated, dried and baked on the substrate with ultraviolet rays was used as a PGME / After being immersed in a mixed solvent of water = 1/1 (volume ratio) for 3 minutes, rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.69. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 4>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a film-coated substrate obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on a substrate was converted into ethyl lactate. After being immersed in (boiling point: 154 ° C.) at 25 ° C. for 3 minutes, it was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.9. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 5>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a polyimide substrate coated, dried and baked on a substrate was irradiated with ultraviolet rays, and a substrate with a film was obtained from a butyl cellosolve ( (Boiling point: 169 ° C.) for 10 minutes at 25 ° C., rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.69. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 6>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a polyimide substrate coated, dried and baked on a substrate was irradiated with ultraviolet rays, and a substrate with a film was obtained from PGME ( (Boiling point: 124 ° C.) at 25 ° C. for 3 minutes, rinsed with water for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.82. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 7>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a film-coated substrate obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on a substrate was converted into ethyl lactate. After being immersed in (boiling point: 154 ° C.) at 25 ° C. for 3 minutes, it was rinsed with water for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.84. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 8>
In the same manner as in Example 1, the liquid crystal aligning agent A obtained in Synthesis Example 2 was used, and the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was converted into diacetone. After being immersed in alcohol (boiling point: 169 ° C.) at 25 ° C. for 3 minutes, rinsed with water for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.77. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 9>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on the substrate was converted into MMP ( (Boiling point: 145 ° C.) at 25 ° C. for 3 minutes, rinsed with water for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.77. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 10>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent B obtained in Synthesis Example 4, a polyimide substrate coated, dried and baked on a substrate was irradiated with ultraviolet rays, and a substrate with a film was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.72. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 11>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent B obtained in Synthesis Example 4 and irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays, the film-coated substrate was added to ethyl lactate (boiling point: 154 ° C.) at 25 ° C. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 2.11. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 12>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent C obtained in Synthesis Example 6, a substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.53. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 13>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent C obtained in Synthesis Example 6, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was treated with ethyl lactate (boiling point: 154 ° C.) at 25 After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.94. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 14>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent D obtained in Synthesis Example 8, the polyimide substrate coated, dried and baked on the substrate was irradiated with ultraviolet rays, and the substrate with a film was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.40. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 15>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent D obtained in Synthesis Example 8, the polyimide film coated, dried and baked on the substrate was irradiated with ultraviolet rays, and the film-coated substrate was added to ethyl lactate (boiling point: 154 ° C.) at 25. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.70. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 16>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent A obtained in Synthesis Example 2, the polyimide substrate coated, dried and baked on the substrate was irradiated with ultraviolet rays, and the substrate with a film was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.37. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 17>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent A obtained in Synthesis Example 2, a polyimide film coated, dried and baked on a substrate was irradiated with ultraviolet rays, and a film-coated substrate was added to ethyl lactate (boiling point: 154 ° C.) at 25. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.77. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 18>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent E obtained in Synthesis Example 10, a substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.33. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 19>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent E obtained in Synthesis Example 10, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was treated with ethyl lactate (boiling point: 154 ° C.) at 25 ° C. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.2. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 20>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent F obtained in Synthesis Example 12, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was added to PGME (boiling point: 120 ° C.) at 25 ° C. After immersing for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.15. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 21>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent F obtained in Synthesis Example 12, a substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was added to ethyl lactate (boiling point: 154 ° C.) at 25 ° C. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.12. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 22>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent G obtained in Synthesis Example 14, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was added to PGME (boiling point: 120 ° C.) at 25 ° C. Then, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.11. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Example 23>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent G obtained in Synthesis Example 14, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was treated with ethyl lactate (boiling point: 154 ° C.) at 25 ° C. After immersing at 3 ° C. for 3 minutes, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.10. Further, when the liquid crystal alignment film was visually observed, no unevenness was observed.

<Comparative Example 1>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on a substrate was obtained as IPA ( (Boiling point: 82.4 ° C.) at 25 ° C. for 3 minutes and then dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.2. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative example 2>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a polyimide film coated, dried and baked on the substrate was irradiated with ultraviolet rays, and the film-coated substrate was treated with water ( (Boiling point: 100 ° C.) for 3 minutes, rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.25. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 3>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on a substrate was obtained as PG ( (Boiling point: 187 ° C.) for 3 minutes at 25 ° C., rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.45. Further, when the alignment film was visually observed, large unevenness and whitening were observed.

<Comparative Example 4>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on the substrate was used as a GBL ( (Boiling point: 204 ° C.) at 25 ° C. for 3 minutes, rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The obtained liquid crystal alignment film was completely dissolved, and anisotropy measurement and film thickness measurement were impossible.

<Comparative Example 5>
In the same manner as in Example 1, using the liquid crystal aligning agent A obtained in Synthesis Example 2, a substrate with a film obtained by irradiating ultraviolet rays onto a polyimide film coated, dried and baked on the substrate was treated with NMP ( (Boiling point: 202 ° C.) for 3 minutes at 25 ° C., rinsed with IPA for 1 minute, and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The obtained liquid crystal alignment film was completely dissolved, and anisotropy measurement and film thickness measurement were impossible.

<Comparative Example 6>
In the same manner as in Example 1, the liquid crystal alignment agent A obtained in Synthesis Example 2 was used, and the liquid crystal alignment on the film-coated substrate obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays. The anisotropic magnitude with respect to the orientation direction of the film was 1.18. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 7>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent B obtained in Synthesis Example 4 and applying UV light to the polyimide film coated, dried and baked on the substrate, the substrate with the film was made IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.19. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative Example 8>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent B obtained in Synthesis Example 4, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After being immersed, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.17. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 9>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the film-coated substrate obtained by irradiating the polyimide film coated, dried and baked on the substrate using the liquid crystal alignment agent B obtained in Synthesis Example 4 The magnitude of the property was 1.12. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 10>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent C obtained in Synthesis Example 6, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was applied to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.12. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative Example 11>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent C obtained in Synthesis Example 6, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After being immersed, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.16. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 12>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the substrate with the film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays using the liquid crystal alignment agent C obtained in Synthesis Example 6 The magnitude of the property was 1.11. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 13>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent D obtained in Synthesis Example 8 and applying UV light to the polyimide film coated, dried and baked on the substrate, the substrate with the film was applied to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.19. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative example 14>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent D obtained in Synthesis Example 8, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After the immersion, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.19. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 15>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the film-coated substrate obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays using the liquid crystal alignment agent D obtained in Synthesis Example 8. The size of was 1.12. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 16>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent A obtained in Synthesis Example 2, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was changed to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.17. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative Example 17>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent A obtained in Synthesis Example 2, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After being immersed, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.17. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 18>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the substrate with the film obtained by irradiating the polyimide film coated, dried and baked on the substrate using the liquid crystal alignment agent A obtained in Synthesis Example 2 The magnitude of the property was 1.12. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 19>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent E obtained in Synthesis Example 10, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was applied to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.11. Further, when the alignment film was visually observed, a little unevenness was observed.

<Comparative Example 20>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Using the liquid crystal aligning agent E obtained in Synthesis Example 10, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After the immersion, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.11. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 21>
Example 1 was repeated except that 254 nm ultraviolet rays were irradiated at 0.5 J / cm ² . Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the substrate with the film obtained by irradiating the polyimide film coated, dried and baked on the substrate using the liquid crystal alignment agent E obtained in Synthesis Example 10 The magnitude of the property was 1.08. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 22>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent F obtained in Synthesis Example 12, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was applied to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.04. Further, when the alignment film was visually observed, unevenness was observed.

<Comparative Example 23>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent F obtained in Synthesis Example 12, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After being immersed, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.10. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 24>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the substrate with the film obtained by irradiating the polyimide film coated, dried and baked on the substrate using the liquid crystal alignment agent F obtained in Synthesis Example 12 The magnitude of the property was 1.06. No film unevenness of the liquid crystal alignment film was observed.

<Comparative Example 25>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent G obtained in Synthesis Example 14, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was applied to IPA (boiling point: 82.4 ° C.). After being immersed for 3 minutes at 25 ° C., it was dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.09. Further, when the alignment film was visually observed, unevenness was observed.

<Comparative Example 26>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Using the liquid crystal aligning agent G obtained in Synthesis Example 14, the substrate with a film obtained by irradiating the polyimide film coated, dried and baked on the substrate with ultraviolet rays was placed in water (boiling point: 100 ° C.) for 3 minutes. After being immersed, the substrate was rinsed with IPA for 1 minute and dried in an oven at 80 ° C. for 10 minutes to obtain a liquid crystal alignment film.
The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was 1.09. Further, when the liquid crystal alignment film was visually observed, some unevenness was observed.

<Comparative Example 27>
The procedure was the same as Example 1 except that 1.0 J / cm ^{2 of} 254 nm ultraviolet light was irradiated. Anisotropy with respect to the alignment direction of the liquid crystal alignment film on the substrate with the film obtained by irradiating the polyimide film coated, dried and baked on the substrate using the liquid crystal alignment agent G obtained in Synthesis Example 14 The magnitude of the property was 1.07. No film unevenness of the liquid crystal alignment film was observed.

Table 1 summarizes the types of solvents used, the degree of anisotropy of the obtained liquid crystal alignment film, and film unevenness for Examples 1 to 22 and Comparative Examples 1 to 27 described above.

The liquid crystal alignment film obtained by the production method of the present invention has high anisotropy, and is widely useful for TN devices, STN devices, TFT liquid crystal devices, and vertical alignment type liquid crystal display devices. Furthermore, by imparting high anisotropy, afterimages derived from liquid crystal orientation, for example, afterimages caused by alternating current drive generated in liquid crystal display elements of the IPS drive method or the FFS drive method can be reduced. This is particularly useful as a liquid crystal alignment film of a liquid crystal display element of an LCD system or FFS driving system or a liquid crystal television.
The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2011-202229 filed on September 15, 2011 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims

Polarized radiation on an imidized film obtained by applying and baking a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of the polyimide and an organic solvent on a substrate Then, at least one selected from the group consisting of the following formula (A-1), formula (A-2), formula (A-3), formula (A-4), and formula (A-5) A method for producing a liquid crystal alignment film, which comprises performing a contact treatment with a solution containing a seed organic solvent.

(In Formula (A-1), A 1 is a hydrogen atom or an acetyl group, A 2 is an alkyl group having 1 to 6 carbon atoms, R 2 is a hydrogen atom or a methyl group, and n is 1 or 2 In formula (A-2), A 3 is an alkyl group having 1 to 4 carbon atoms, and in formula (A-3), R 3 and R 4 are each independently a hydrogen atom or In formula (A-4), A 5 and A 6 each independently represents an alkyl group having 1 to 4 carbon atoms, and in formula (A-5), A 6 represents 3 carbon atoms. 6 to 6 alkyl groups or cycloalkyl groups.)
The method for producing a liquid crystal alignment film according to claim 1, wherein the organic solvent has a boiling point of 100 to 180 ° C.
3. The method for producing a liquid crystal alignment film according to claim 1, wherein the organic solvent is 1-methoxy-2-propanol, ethyl lactate, diacetone alcohol, methyl 3-methoxypropionate, or ethyl 3-ethoxypropionate. .
The polymer contains at least one polymer selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (3) and an imidized polymer of the polyimide precursor. 4. A method for producing a liquid crystal alignment film according to any one of 3 above.

(In the formula (3), X 1 is at least one selected from the group consisting of structures represented by the following formulas (X1-1) to (X1-9), and Y 1 is a divalent organic group. R 1 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

(In Formula (X1-1), R 3 , R 4 , R 5 , and R 6 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms. Group, alkenyl group, or phenyl group.)
From the group consisting of a polyimide precursor in which the polymer contains 60 mol% or more of the structural unit represented by the formula (3) with respect to 1 mol of the whole polymer, and an imidized polymer of the polyimide precursor. The method for producing a liquid crystal alignment film according to claim 4, which is at least one selected.
In the formula (3), the method of manufacturing a liquid crystal alignment film according to claim 4 in which X 1 is represented by the formula (X1-1).
5. The liquid crystal alignment film production according to claim 4, wherein, in the formula (3), X 1 is at least one selected from the group consisting of structures represented by the following formulas (X1-10) and (X1-11). Method.
In the formula (3), the method of manufacturing a liquid crystal alignment film according to claim 4, wherein at least one of Y 1 is selected from the group consisting of structures represented by the following formulas (4) and (5).

(In Formula (5), Z 1 is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 10 carbon atoms.)
In the formula (3), the method of manufacturing a liquid crystal alignment film according to claim 8 Y 1 is a structure represented by the formula (4).
A liquid crystal obtained by irradiating a film obtained by applying and baking a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of the polyimide on a base plate, with polarized radiation. A contact treatment solution for an alignment film, selected from the group consisting of the following formula (A-1), formula (A-2), formula (A-3), formula (A-4), and formula (A-5) A contact treatment liquid for a liquid crystal alignment film comprising a solution containing at least one organic solvent.

(In Formula (A-1), A 1 is a hydrogen atom or an acetyl group, A 2 is an alkyl group having 1 to 6 carbon atoms, R 2 is a hydrogen atom or a methyl group, and n is 1 or 2 In formula (A-2), A 3 is an alkyl group having 1 to 4 carbon atoms, and in formula (A-3), R 3 and R 4 are each independently a hydrogen atom or In formula (A-4), A 5 and A 6 each independently represents an alkyl group having 1 to 4 carbon atoms, and in formula (A-5), A 6 represents 3 carbon atoms. 6 to 6 alkyl groups or cycloalkyl groups.)
A liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to any one of claims 1 to 9.
A liquid crystal display device comprising the liquid crystal alignment film according to claim 11.