JP5045913B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent used for forming a liquid crystal alignment film of a liquid crystal display element. More specifically, the present invention relates to a liquid crystal aligning agent that provides a liquid crystal aligning film having good electrical characteristics and good printability.

Currently, as a liquid crystal display element, a liquid crystal alignment film made of polyamic acid, polyimide, or the like is formed on the surface of a substrate on which a transparent conductive film is provided to form a liquid crystal display element substrate. A nematic liquid crystal layer having positive dielectric anisotropy is formed in a cell having a sandwich structure so that the major axis of the liquid crystal molecules is continuously twisted 90 degrees from one substrate to the other. A TN liquid crystal display element having a so-called TN (twisted nematic) liquid crystal cell is known. Further, STN (Super Twisted Nematic) type liquid crystal display elements and vertical alignment type liquid crystal display elements, which have a higher contrast than the TN type liquid crystal display elements and have less viewing angle dependency, have been developed. This STN liquid crystal display element uses nematic liquid crystal blended with a chiral agent which is an optically active substance as liquid crystal, and the major axis of liquid crystal molecules is continuously twisted over 180 degrees between substrates. The birefringence effect generated by the above is utilized. On the other hand, as described in Non-Patent Document 1 and Patent Document 1, a vertically aligned liquid crystal display element called an MVA method has been proposed in which protrusions are formed on ITO to control the alignment direction of liquid crystals. Yes. The MVA liquid crystal display element is excellent in terms of manufacturing process, such as excellent viewing angle and contrast, and need not be rubbed in forming the liquid crystal alignment film. As a liquid crystal alignment film suitable for the TN, STN, and MVA methods, performance such as a short afterimage erasing time of the liquid crystal display element is required. In addition, as an alignment agent used for forming these liquid crystal alignment films, excellent printability is required in offset printing. As a prior art for shortening the afterimage erasing time of the liquid crystal display element, there is a technique described in Patent Document 2. Patent Document 2 aims to eliminate afterimages and image sticking phenomena by adding an additive represented by diphenylbenzidine in the alignment film or copolymerizing it in polyimide. However, the method described in this prior art has a problem in that the bonding force between the substance to be added and the polyimide is weak, and the voltage holding ratio is lowered by the diffusion of the additive into the liquid crystal from the alignment film.
“Liquid Crystal” Vol. 3 No. 2 117 (1999) Japanese Patent Laid-Open No. 11-258605 Japanese Patent Laid-Open No. 6-3311990

  The present invention has been made in view of the above-mentioned problems, and the object thereof is to reduce the accumulated charge related to the seizure property while maintaining the voltage holding ratio in the polyimide-based liquid crystal alignment film. And providing a liquid crystal aligning agent having excellent printability and a liquid crystal display element using the same.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are as follows.
A liquid crystal comprising at least one polymer selected from a polyamic acid comprising a repeating unit represented by the following formula (I-1) and a polyimide comprising a repeating unit represented by the following formula (I-2): This is achieved with an aligning agent.

Here, P ¹ and P ² represent a tetravalent organic group, and Q ¹ and Q ² represent a divalent organic group including a structure represented by the following formula (1).

(Wherein R ₁ , R ₂ and R ₃ are each independently hydrogen, an alkyl group, an alkoxy group, or an aromatic group, R ₄ is hydrogen or an alkyl group, and m is 2. )
In the above formula (1), a liquid crystal aligning agent in which R ₁ is hydrogen is preferable. More preferably in the above formula (1) are _those wherein R 1, _{R 2} and _{R 3} are hydrogen, particularly preferably hydrogen _R 1, _{R 2} and _{R 3, R 4} is a methyl group It is.
Further, it is preferable from the above formula (I-1) ^{P 1} and at least a portion of ^{P 2} in the formula (I-2) in the 2,3,5-tricarboxycyclopentylacetic dianhydride in.

The above-mentioned object and advantage of the present invention are secondly.
The liquid crystal alignment film is obtained by using the liquid crystal aligning agent described above and has an imidization ratio of 30 to 98%.

According to the present invention, the above objects and advantages of the present invention are further divided into the following:
This is achieved by a liquid crystal display device comprising the liquid crystal alignment film of the present invention.

  Hereinafter, the present invention will be described in detail.

  The liquid crystal aligning agent of this invention is comprised from at least 1 sort (s) among the polyamic acid polymer (henceforth a specific polyamic acid) of a specific structure and the polyimide acid polyimide (henceforth a specific polyimide) of a specific structure.

[Specific polyamic acid, specific polyimide]
The diamine components Q ¹ and Q ² in the specific polyamic acid and the specific polyimide are represented by the following formula (1).

In the above formula (1), R ₁ , R ₂ and R ₃ are each independently hydrogen, an alkyl group, an alkoxy group, an amino group or an aromatic group. Among these, the alkyl group and alkoxyl group are preferably an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms. Examples of the alkyl group and the alkyl group contained in the alkoxy group include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methyl-propyl group, 3-methyl-propyl group, n- Examples include a pentyl group and an n-hexyl group. Examples of the aromatic group include a phenyl group, a tolyl group, and a naphthyl group. Of these, R ₁ is preferably hydrogen or a methyl group, and R ₂ and R ₃ are preferably hydrogen, a methyl group, an ethyl group, an n-propyl group, a methoxy group, an ethoxy group, or a phenyl group. Each R ₄ is independently hydrogen or an alkyl group. Among these, the alkyl group is preferably an alkyl group having 1 to 6 carbon atoms. For example, a methyl group, an ethyl group, an n-propyl group, etc. are mentioned.
In the above formula (1), m is 2 .
Specific examples of the structure of the above formula (1) include the following.

In synthesizing the specific polyamic acid and the specific polyimide represented by the above formulas (I-1) and (I-2), the acid anhydride is not particularly limited, but preferred examples thereof include 1, 2, 3, 4 -Cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a , 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, cis-3,7-dibutylcycloocta -1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1, 3, 3a 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3 2.1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3- Methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo " 5.3.1.0 ^2,6 "undecane-3,5,8,10-tetraone, pyromellitic dianhydride and the like. These acid dianhydrides can be used alone or in combination of two or more.

  Moreover, in synthesizing the specific polyamic acid and polyimide represented by each of the above formulas (I-1) and (I-2), other diamines are added in addition to the diamine compound having the structure represented by the formula (1). You may use together. Examples of other preferable diamine compounds include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,5- Diaminonaphthalene, 2,7-diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9 , 9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(P-phenylenediisopropylidene) bisaniline, 4,4'-(m-phenylenediiso (Ropyridene) bisaniline, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2 , 6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3 , 6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole and the like. These other diamine compounds can be used alone or in combination of two or more.

In the case where the liquid crystal aligning agent of the present invention has pretilt angle expression, a part of Q ¹ and Q ^{2 in} the above formulas (I-1) and (I-2) is represented by the following formula (Q-1) and the following It is preferably at least one group represented by the formula (Q-2). That is, a diamine having a group represented by the following formula (Q-1) or the following formula (Q-2) (hereinafter sometimes referred to as a specific diamine compound) is used. These may be used alone or in combination of two or more.

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ⁶ has 10 carbon atoms. An alkyl group of -20, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a monovalent organic group having a fluorine atom having 6 to 20 carbon atoms.)

(In the formula, X is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S— or an arylene group, and R ⁷ has 4 carbon atoms. It is a divalent organic group having an alicyclic skeleton of ˜40.)
In the above formula (Q-1), examples of the alkyl group having 10 to 20 carbon atoms represented by R ⁶ include n-decyl group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n- An octadecyl group, n-eicosyl group, etc. are mentioned. Examples of the organic group having an alicyclic skeleton having 4 to 40 carbon atoms represented by R ⁶ in the above formula (Q-1) and R ⁷ in the above formula (Q-2) include cyclobutane and cyclopentane. Groups having an alicyclic skeleton derived from cycloalkane such as cyclohexane and cyclodecane; groups having a steroid skeleton such as cholesterol and cholestanol; groups having a bridged alicyclic skeleton such as norbornene and adamantane. Among these, a group having a steroid skeleton is particularly preferable. The organic group having an alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom, or a fluoroalkyl group, preferably a trifluoromethyl group.

Furthermore, examples of the group having 6 to 20 carbon atoms represented by R ⁶ in the formula (Q-1) include carbon atoms such as an n-hexyl group, an n-octyl group, and an n-decyl group. A linear alkyl group having 6 or more; an alicyclic hydrocarbon group having 6 or more carbon atoms such as a cyclohexyl group or a cyclooctyl group; an organic group such as an aromatic hydrocarbon group having 6 or more carbon atoms such as a phenyl group or a biphenyl group And a group in which part or all of the hydrogen atoms are substituted with a fluoroalkyl group such as a fluorine atom or a trifluoromethyl group.

  X in the formula (Q-1) and the formula (Q-2) is a single bond, -O-, -CO-, -COO-, -OCO-, -NHCO-, -CONH-, -S. -Or an arylene group. Examples of the arylene group include a phenylene group, a tolylene group, a biphenylene group, and a naphthylene group. Of these, groups represented by —O—, —COO—, and —OCO— are particularly preferable. Specific examples of the diamine having the group represented by the above formula (Q-1) include dodecanoxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy- Preferred examples include 2,4-diaminobenzene and compounds represented by the following formulas (2) to (6).

  Specific examples of the diamine compound having a group represented by the formula (Q-2) include diamine compounds represented by the following formulas (7) to (9).

  Of these, particularly preferred are compounds represented by the above formulas (2), (4), (6) and (7).

The use ratio of the specific diamine with respect to the total amount of diamine varies depending on the size of the pretilt angle to be expressed, but in the case of a TN type or STN type liquid crystal display element, 0 to 5 mol%, in the case of a vertical alignment type liquid crystal display element 5 to 50 mol% is preferable.
It is represented by the formula (1) in the specific polyamic acid or the specific polyimide. The proportion of the structure derived from diamine is preferably 0.5 mol% to 50 mol% of the structure derived from all diamines contained in the specific polyamic acid or specific polyimide, and is 1 mol% to 40 mol%. More preferably.
In addition to the specific polyamic acid and the specific polyimide, other polyamic acid and polyimide may be used in combination for the liquid crystal aligning agent of the present invention.

[Other polyamic acids]
<Tetracarboxylic dianhydride>
As tetracarboxylic dianhydride used for the synthesis | combination of another polyamic acid, alicyclic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride are preferable, for example. Specific examples of the alicyclic tetracarboxylic dianhydride include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5 -Cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6 -Tetracarboxylic acid Anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 2,3,4,5 -Tetrahydrofurantetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1 , 3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1 , 3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1 , 3-dione, 1,3,3a, 4 5,9b-Hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4 5,9b-Hexahydro-7-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4 5,9b-Hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4 5,9b-Hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4 5,9b-Hexahydro-5,8-dimethyl-5 (tetrahydro 2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1 , 2-dicarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3.2.1] Octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene -1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9-dioxatricyclo “5.3.1” 0.0 ^2,6 "undecane-3,5,8,10-tetrao , Compounds represented by the following formulas (I) and (II),

(Wherein R ¹ and R ³ represent a divalent organic group having an aromatic ring, R ² and R ⁴ represent a hydrogen atom or an alkyl group, and a plurality of R ² and R ⁴ are the same. But it may be different.)
In addition, aliphatic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride;
Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis ( 3,4-dicar Boxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2 , 2 ′, 3,3′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis ( Triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride, ethylene glycol-bis ( Anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate) Retate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis ( Anhydrotrimellitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (10) to (13). These may be used alone or in combination of two or more.

Among the tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxy Cyclopentyl acetic acid dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5 -Diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2-carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b- Xahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8- Methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5 8-Dimethyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, bicyclo [2.2.2] -oct-7-ene -2,3,5,6-tetracarboxylic dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5 ' -Dione), 5- (2,5-dioxotetrahydro-3-fura ) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, 4,9- Dioxatricyclo “5.3.1.0 ^2,6 ” undecane-3,5,8,10-tetraone, among the compounds represented by the above formula (I), the following formulas (14) to (16) An alicyclic tetracarboxylic dianhydride such as a compound represented by the following formula (17) among the compounds represented by the above formula (II) and the alicyclic tetracarboxylic dianhydride such as a compound represented by: From the viewpoint of exhibiting good liquid crystal orientation, particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4 -Cyclobutanetetracarboxylic dianhydride, 2 3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] Furan-1,3-dione, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 3,5,6-tricarbonyl-2- Carboxynorbornane-2: 3,5: 6-dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′- Dione), 5- (2,5-dioxotetrahi (Ro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride, Examples include 4,9-dioxatricyclo "5.3.1.0 ^2,6 " undecane-3,5,8,10-tetraone and a compound represented by the following formula (14).

Among the other tetracarboxylic dianhydrides other than the alicyclic tetracarboxylic dianhydrides, for example, butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 1, 4,5,8-naphthalenetetracarboxylic dianhydride and the like.
Among these tetracarboxylic dianhydrides, the alicyclic tetracarboxylic dianhydride is preferably 50 mol% or more based on the total tetracarboxylic dianhydrides.

<Diamine compound>
Examples of diamines used for the synthesis of other polyamic acids include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, and 4,4′-diaminodiphenyl sulfide. 4,4′-diaminodiphenylsulfone, 2,2′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4, , 4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3, '-Diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3 -Bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9 -Dimethyl-2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4'-methylene-bis (2- Chloroaniline), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl, 3,3 '-Dimethoxy-4,4'-diaminobiphenyl, 1,4,4'-(p-phenyleneisopropylidene) bisaniline, 4,4 '-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4 -(4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino Aromatic diamines such as -2-trifluoromethyl) phenoxy] -octafluorobiphenyl;
1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene methylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine, 4 Aliphatic and cycloaliphatic diamines such as 4,4'-methylenebis (cyclohexylamine);
2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino-2,4 -Dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 2,4-diamino-6-isopropoxy-1,3 , 5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl -S-triazine, 2,4-diamino-1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6- Aminopurine, 5,6-diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3,8-diamino-6 Phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl A diamine having two primary amino groups and a nitrogen atom other than the primary amino group in the molecule, such as 3,6-diaminocarbazole and N-phenyl-3,6-diaminocarbazole; The diaminoorganosiloxane represented by these is mentioned. These diamines can be used alone or in combination of two or more.

(In the formula, R ⁵ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ⁵ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) Is an integer.)
Of these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,5-diaminonaphthalene, 2,7 -Diaminofluorene, 9,9-dimethyl-2,7-diaminofluorene, 4,4'-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4 -Aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-pheny Range isopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-cycl Rhohexanediamine, 4,4′-methylenebis (cyclohexylamine), 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3 , 4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N -Phenyl-3,6-diaminocarbazole is preferred.
Another polyimide can be produced by dehydrating and ring-closing the other polyamic acid.

<Synthesis of polyamic acid>
The ratio of tetracarboxylic dianhydride and diamine used for the polyamic acid synthesis reaction is 0.2 to 2 equivalents of tetracarboxylic dianhydride acid anhydride group to 1 equivalent of amino group of diamine. The ratio is preferably, more preferably 0.3 to 1.2 equivalent.
The polyamic acid synthesis reaction is preferably performed in an organic solvent under a temperature condition of −20 ° C. to 150 ° C., more preferably 0 to 100 ° C.

  Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. For example, 1-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 3- Amide solvents such as butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, 3-hexyloxy-N, N-dimethylpropanamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea And aprotic polar solvents such as hexamethylphosphotriamide; and phenolic solvents such as m-cresol, xylenol, phenol, and halogenated phenol. The amount of organic solvent used (α) is such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight based on the total amount of the reaction solution (α + β). It is preferable that

  In addition, the said organic solvent can use together the alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbon, etc. which are poor solvents of a polyamic acid in the range in which the polyamic acid to produce | generate does not precipitate. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol. , Ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, malon Acid diethyl, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i Propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, diisobutyl ketone, isoamylpropionate, isoamylisobutyrate , And the like di-iso-pentyl ether.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. Then, the reaction solution is poured into a large amount of poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure, or the reaction solution is distilled off under reduced pressure with an evaporator to obtain a polyamic acid. Further, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating it with a poor solvent, or performing the step of evaporating under reduced pressure with an evaporator once or several times.

<Dehydration ring closure reaction>
The polyimide in the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing part or all of the polyamic acid.
The polyamic acid is dehydrated and closed by (i) a method of heating the polyamic acid, or (ii) dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to this solution, and heating as necessary. By the method.
The reaction temperature in the method of heating the polyamic acid (i) is preferably 50 to 200 ° C, more preferably 60 to 170 ° C. When the reaction temperature is less than 50 ° C., the dehydration ring-closing reaction does not proceed sufficiently, and when the reaction temperature exceeds 200 ° C., the molecular weight of the imidized polymer obtained may decrease.

  On the other hand, in the method (ii) of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid solution, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride is used as the dehydrating agent. Can do. The amount of the dehydrating agent used depends on the desired imidization ratio, but is preferably 0.01 to 20 mol per 1 mol of the polyamic acid repeating unit. Moreover, as a dehydration ring closure catalyst, tertiary amines, such as a pyridine, a collidine, a lutidine, a triethylamine, can be used, for example. However, it is not limited to these. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. The imidation rate can be increased as the amount of the above dehydrating agent and dehydrating ring-closing agent increases. In addition, as an organic solvent used for dehydration ring closure reaction, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And reaction temperature of dehydration ring closure reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 10-150 degreeC. Moreover, the obtained specific polymer can be refine | purified by performing operation similar to the purification method of a polyamic acid with respect to the reaction solution obtained in this way.

In the polyimide used in the present invention, the ratio of repeating units having an imide ring in all repeating units (hereinafter also referred to as “imidation ratio”) is 40 mol% or more, preferably 50 mol% or more. By using a polymer having an imidization ratio of 40 mol% or more, a liquid crystal aligning agent capable of forming a liquid crystal alignment film having a short afterimage erasing time can be obtained.
The imidization rate can be determined by the following method.

[Method for measuring imidization rate of imidized polymer]
The imidized polymer is dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR is measured at room temperature using tetramethylsilane as a reference substance, and obtained by the formula represented by the following formula (ii). Can do.
Imidation ratio (%) = (1-A ¹ / A ² × α) × 100 ------ (ii)
A ¹ : NH group proton-derived peak area (10 ppm)
A ² : Peak area derived from other protons α: Number ratio of other protons to one proton of NH group in polymer precursor (polyamic acid)

<End-modified polymer>
The polyamic acid and polyimide used in the present invention may be of a terminal modified type with a controlled molecular weight. By using this terminal-modified polymer, the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing a polyamic acid. Here, as the acid monoanhydride, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride , N-hexadecyl succinic anhydride and the like. Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, and n-undecylamine. N-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Can do. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

[Solution viscosity]
The polymer used in the aligning agent of the present invention preferably has a viscosity of 20 to 800 mPa · s, and preferably has a viscosity of 30 to 500 mPa · s when a 10% solution is obtained. Is more preferable.
The solution viscosity (mPa · s) of the polymer was measured at 25 ° C. using an E-type rotational viscometer for a solution diluted to a predetermined solid content concentration using a predetermined solvent.

[Liquid crystal aligning agent]
The liquid crystal aligning agent of the present invention is constituted by dissolving the specific polymer usually in an organic solvent.
The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 to 200 degreeC, More preferably, it is 20 to 60 degreeC.
As an organic solvent which comprises the liquid crystal aligning agent of this invention, the solvent illustrated as what is used for the synthesis reaction of a polyamic acid can be mentioned. Moreover, the poor solvent illustrated as what can be used together in the case of the synthesis reaction of a polyamic acid can also be selected suitably, and can be used together.
The solid content concentration in the liquid crystal aligning agent of the present invention is selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the coating film thickness is When the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive and a good liquid crystal alignment film cannot be obtained. In addition, the viscosity of the liquid crystal aligning agent increases, resulting in poor coating characteristics.

  The particularly preferable solid content concentration range varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, when the spinner method is used, the range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the ink jet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s.

  Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include 1-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy- 4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether , Ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl Ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, Examples include 3-hexyloxy-N, N-dimethylpropanamide, diisobutyl ketone (DIBK), isoamyl propionate, isoamyl isobutyrate, and diisopentyl ether. These can be used alone or in admixture of two or more. Of these, 3-butoxy-N, N-dimethylpropanamide, 3-methoxy-N, N-dimethylpropanamide, and 3-hexyloxy-N, N-dimethylpropanamide exhibit particularly good printability. preferable.

The liquid crystal aligning agent of this invention may contain the functional silane containing compound and the epoxy compound from a viewpoint which improves the adhesiveness with respect to the substrate surface within the range which does not impair the target physical property. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl- , 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N -Bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. can be mentioned. Examples of such epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromo-neopentyl glycol diglycidyl ether, 1,3,5,6- tetraglycidyl-2,4-hexanediol, N, N, N ', N' - Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-dia Bruno diphenylmethane, 3- (N-Ariru N Gurishijiru) aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl A cyclohexane etc. can be mentioned. The blending ratio of these functional silane-containing compounds and epoxy group-containing compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

<Liquid crystal display element>
The liquid crystal display element obtained using the liquid crystal aligning agent of this invention can be manufactured, for example with the following method.

(1) The liquid crystal aligning agent of the present invention is applied to one surface of a substrate provided with a patterned transparent conductive film by an offset printing method, a spin coating method, or an ink jet printing method, and then the coated surface is heated. To form a coating film. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, alicyclic polyolefin, or the like can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane-containing compound, a functional titanium-containing compound, or the like is previously applied to the surface of the substrate. You can also After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied aligning agent. The pre-baking temperature is preferably 30 to 300 ° C, more preferably 40 to 200 ° C, and particularly preferably 50 to 150 ° C. Thereafter, a baking (post-baking) step is performed for the purpose of completely removing the solvent and heat imidizing the polyamic acid. The firing (post-bake) temperature is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. In this way, the liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film that becomes a liquid crystal aligning film by removing the organic solvent after coating, and further proceeds with dehydration ring closure by further heating. An imidized liquid crystal alignment film can also be used. The film thickness of the liquid crystal alignment film to be formed is preferably 0.001 to 1 μm, and more preferably 0.005 to 0.5 μm.

(2) A rubbing process is performed in which the formed coating film surface is rubbed in a certain direction with a roll wound with a cloth made of a fiber such as nylon, rayon, or cotton. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film. Further, by partially irradiating the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention with ultraviolet rays as disclosed in, for example, JP-A-6-222366 and JP-A-6-281937. A resist film is partially formed on the surface of the liquid crystal alignment film that has been subjected to a treatment for changing the pretilt angle or a rubbing treatment as disclosed in JP-A-5-107544, which is different from the previous rubbing treatment. The visibility characteristics of the liquid crystal display element can be improved by removing the resist film after performing the rubbing treatment in the direction and changing the liquid crystal alignment ability of the liquid crystal alignment film.

(3) Two substrates on which the liquid crystal alignment film is formed as described above are manufactured, and the two substrates are separated by a gap (cell gap) so that the rubbing directions in the respective liquid crystal alignment films are orthogonal or antiparallel. ), And the periphery of the two substrates are bonded together using a sealant, and liquid crystal is injected and filled in the cell gap defined by the substrate surface and the sealant, and the injection hole is sealed. A liquid crystal cell is constructed. A polarizing plate is disposed on the outer surface of the liquid crystal cell, that is, on the other surface side of each substrate constituting the liquid crystal cell, and the polarization direction thereof coincides with or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on one surface of the substrate. A liquid crystal display element is obtained by pasting together.
Here, as the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used.

Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, nematic liquid crystal is preferable. For example, Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenyl cyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal. Liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. Further, for these liquid crystals, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck). Etc. can also be used. Furthermore, a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate can also be used.
Further, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film in which a polarizing film called an H film that absorbs iodine while sandwiching and stretching polyvinyl alcohol is sandwiched between cellulose acetate protective films. The polarizing plate which consists of itself can be mentioned.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[Printability evaluation]
A 127 mm (D) × 127 mm (W) × 1.1 mm (H) glass substrate having an ITO film formed on the entire surface of one side is prepared, and a liquid crystal alignment film coating printer (Nissha Printing Co., Ltd.) is prepared on this glass substrate. The liquid crystal aligning agent obtained in the above experiment was filtered with a microfilter having a pore diameter of 0.2 μm using an Angstromer S-40L) and then applied to the transparent electrode surface. It dried with the hotplate contact | adhesion type preliminary dryer set to 80 degreeC, and baked at 200 degreeC for 10 minute (s), and formed the liquid crystal aligning film on the glass substrate with an ITO film | membrane. The obtained alignment film was evaluated for unevenness by visual observation, and a film having no unevenness was marked with ◯, and a film with unevenness was marked with Δ.

[Voltage holding ratio]
A voltage of 5 V at 60 ° C. was applied to the liquid crystal display element at an application time of 60 microseconds with a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from the application release was measured. The measuring apparatus used was VHR-1 manufactured by Toyo Corporation.

[Burn-in test]
A cell having the ITO electrode shown in FIG. 1 was produced. A DC voltage of 6.0 V was applied to the electrode A, and a DC voltage of 0.5 V was applied to the electrode B at room temperature for 60 hours. After releasing the stress, a DC voltage of 0.1 to 5.0 V was applied to the electrodes A and B in increments of 0.1 V. The image sticking characteristics were determined based on the luminance difference between the electrodes A and B at each voltage. When the brightness difference was large, it was judged that the burn-in characteristic was bad. The case where no seizure was observed was marked with ◎, the case where seizure occurred very little, ○, the case where seizure was weak, Δ, and the case where seizure occurred strongly, x.

[Imidation rate evaluation of alignment film]
The imidation ratio of the alignment film was measured by an infrared absorption measurement method. The imidization rate measurement method by infrared absorption measurement is based on the formation of an alignment film on a silicon wafer with high infrared light transmittance, and quantification by paying attention to the spectrum of specific atomic groups whose absorbance changes as the curing temperature changes. This method was performed with reference to literature (J. DURAN and NS VISWANATAN (IBM Research Laboratory), POLYMER IN ELECTRONICS, 239-258 (1984)). As the imidation rate evaluation sample, the sample after the printability evaluation described above was scraped from the substrate.

<Specific polyamic acid synthesis example>
-Synthesis of diamine A-1 giving the structure of the above formula (1)

In a 500 ml three-necked flask in a nitrogen atmosphere, 4,4′-dibromobiphenyl 12.5 g (40 mmol), 4-nitroaniline 13.3 g (96 mmol), sodium t-butoxide 11.5 g (120 mmol), tris (dibenzylidene) Acetone) -dipalladium (Pd ₂ (dba) ₃ ) 1.5 g (1.6 mmol) and 2- (di-t-butylphosphino) biphenyl 1.0 g (3.2 mmol) are added and dissolved by adding 250 ml of toluene. I let you. The reaction solution was stirred and reacted at 120 ° C. for 10 hours under nitrogen. After completion of the reaction, the reaction solution was returned to room temperature and filtered, and the resulting precipitate was dissolved in 400 ml of a mixed solvent of acetone and chloroform (acetone / chloroform = 1/1 volume ratio). Using a separatory funnel, the organic solvent layer was washed with 100 ml of 10 wt% hydrochloric acid water and 400 ml of ion exchange water. The organic solvent layer was dehydrated with magnesium sulfate and concentrated with a rotary evaporator. The resulting crude product was purified by silica gel chromatography to obtain 13.9 g of a dinitro intermediate.
Next, in a nitrogen atmosphere, 6.4 g (15 mmol) of the dinitro intermediate synthesized above and 5.1 g of Pd / C are placed in a 300 ml three-necked flask, 75 ml of THF is added, and the mixture is heated and stirred at 70 ° C. for 1 hour. Thereafter, 9 ml of hydrazine monohydrate was added, and the mixture was reacted by stirring at 80 ° C. for 3 hours under nitrogen. After completion of the reaction, the catalyst was removed by filtration, and the filtrate was concentrated and dried. The obtained solid was recrystallized in ethanol to obtain 4.2 g of diamine A-1. The ¹ H-NMR spectrum of diamine A-1 is shown in FIG.

  -Synthesis of diamine A-2 giving the structure of the above formula (1)

Under a nitrogen atmosphere, in a 500 ml three-necked flask, 12.5 g (40 mmol) of 4,4′-dibromobiphenyl, 14.6 g (96 mmol) of N-methyl-4-nitroaniline, 11.5 g (120 mmol) of sodium-t-butoxide, Tris (dibenzylideneacetone) -dipalladium (Pd ₂ (dba) ₃ ) 1.5 g (1.6 mmol), 2- (di-t-butylphosphino) biphenyl 1.0 g (3.2 mmol) were added, and toluene was added. 250 ml was added and dissolved. The reaction solution was stirred and reacted at 120 ° C. for 10 hours under nitrogen. After completion of the reaction, the reaction solution was returned to room temperature and filtered, and the resulting precipitate was dissolved in 400 ml of a mixed solvent of acetone and chloroform (acetone / chloroform = 1/1 volume ratio). Using a separatory funnel, the organic solvent layer was washed with 100 ml of 10 wt% hydrochloric acid water and 400 ml of ion exchange water. The organic solvent layer was dehydrated with magnesium sulfate and concentrated with a rotary evaporator. The resulting crude product was purified by silica gel chromatography to obtain 14.5 g of a dinitro intermediate.
Next, in a nitrogen atmosphere, 6.8 g (15 mmol) of the dinitro intermediate synthesized above and 5.1 g of Pd / C are placed in a 300 ml three-necked flask, 75 ml of THF is added, and the mixture is heated and stirred at 70 ° C. for 1 hour. Thereafter, 9 ml of hydrazine monohydrate was added, and the mixture was reacted by stirring at 80 ° C. for 3 hours under nitrogen. After completion of the reaction, the catalyst was removed by filtration, and the filtrate was concentrated and dried. The obtained solid was recrystallized in ethanol to obtain 4.1 g of diamine A-2. The ¹ H-NMR spectrum of diamine A-2 is shown in FIG.

○ Synthesis of specific polyamic acid (B-1) 196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 2,2′-dimethyl- as diamine compound 191 g (4 mol) of 4,4′-diaminobiphenyl and 36.6 g (0.1 mol) of A-1 were dissolved in 382 g of N-methyl-2-pyrrolidone and 3,430 g of γ-butyrolactone, and at 40 ° C. About 3,800 g of a polyamic acid solution (with a specific polyamic acid (B-1)) having a solution viscosity of 170 mPa · s reacted for 3 hours was obtained.

○ Synthesis of specific polyamic acid (B-2) 196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 2,2′-dimethyl- as diamine compound 191 g (0.9 mol) of 4,4′-diaminobiphenyl and 39 g (0.1 mol) of A-2 were dissolved in 383 g of N-methyl-2-pyrrolidone and 3,450 g of γ-butyrolactone, and the mixture was heated at 40 ° C. for 3 hours. About 3,800 g of a polyamic acid solution (which is designated as a specific polyamic acid (B-2)) having a reacted solution viscosity of 180 mPa · s was obtained.

○ Synthesis of specific polyamic acid (B-3) 196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 2,2′-dimethyl- as diamine compound 127 g (0.6 mol) of 4,4′-diaminobiphenyl and 156 g (0.4 mol) of A-2 were dissolved in 430 g of N-methyl-2-pyrrolidone and 3,880 g of γ-butyrolactone, and at 40 ° C. for 3 hours. About 3,800 g of a polyamic acid solution (with a specific polyamic acid (B-3)) having a viscosity of 190 mPa · s reacted was obtained.

<Synthesis of specific polyimide>
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), p-phenylenediamine 77 g (0.71 mol) as the diamine compound, N , N′-di (4-aminophenyl) -N, N′-dimethyl-benzidine 39 g (0.1 mol), bisaminopropyltetramethyldisiloxane 25 g (0.10 mol), and 4- (4′- (Trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate 35 g (0.080 mol), aniline as monoamine 1.4 g (0.01 Mol) was dissolved in N- methyl-2-pyrrolidone 960 g, it was reacted for 6 hours at 60 ° C.. A small amount of the resulting polyamic acid solution was taken, NMP was added, and the viscosity was measured with a solution having a solid content concentration of 10%. The result was 42 mPa · s. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was 9.7% by weight. About 3,600 g of an imidized polymer solution having a solution viscosity of 30 mPa · s and an imidization ratio of about 95% (hereinafter referred to as “imidized polymer (C-1)”) was obtained.

<Other polyimide synthesis examples>
Other polyimide synthesis example 1
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), p-phenylenediamine 96 g (0.89 mol) as the diamine compound, 3 , 3 ′-(tetramethyldisiloxane-1,3-diyl) bis (propylamine) 25 g (0.10 mol) and 3,6-bis (4-aminobenzoyloxy) cholestane 13 g (0.02 mol) As a monoamine, 8.1 g (0.03 mol) of n-octadecylamine was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. . A small amount of the resulting polyamic acid solution was taken, NMP was added, and the viscosity was measured with a solution having a solid content concentration of 10%. As a result, it was 60 mPa · s. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with a new γ-butyrolactone (the pyridine and acetic anhydride used for the imidization reaction were removed from the system in this operation), and the solid content concentration was 15 wt%. When the concentration is 6.0% (γ-butyrolactone solution), the solution viscosity is 16 mPa · s and the imidized polymer having an imidization ratio of about 95% (hereinafter referred to as “polyimide (A-1)”) is about 2,000 g. Got.

Other polyimide synthesis example 2
2,3,5-tricarboxycyclopentyl acetic acid dianhydride 112 g (0.50 mol) and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 157 g (0.50 mol), 88 g (0.81 mol) of p-phenylenediamine as the diamine compound, bis 25 g (0.10 mol) aminopropyltetramethyldisiloxane and 35 g (0.080 mol) 4- (4′-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 1.4 g aniline as monoamine (0.015 mol) was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. A small amount of the resulting polyamic acid solution was taken, NMP was added, and the viscosity was measured with a solution having a solid content concentration of 10%. As a result, it was 40 mPa · s. Next, 2,700 g of N-methyl-2-pyrrolidone was added to the obtained polyamic acid solution, 396 g of pyridine and 409 g of acetic anhydride were added, and dehydration ring closure was performed at 110 ° C. for 4 hours. After the imidization reaction, the solvent in the system was replaced with a new γ-butyrolactone (the pyridine and acetic anhydride used in the imidization reaction were removed from the system in this operation), and the solid content concentration was 9.7 wt% ( About 3,600 g of an imidized polymer solution (hereinafter referred to as “polyimide (A-2)”) having a solution viscosity of γ-butyrolactone solution of 26 mPa · s and an imidization ratio of about 89% was obtained.

<Other polyamic acid synthesis examples>
196 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 212 g (1 of 2,2′-dimethyl-4,4′-diaminobiphenyl as diamine compound) 0.0 mol) was dissolved in N-methyl-2-pyrrolidone (370 g) and γ-butyrolactone (3,300 g) and reacted at 40 ° C. for 3 hours, and a solution having a viscosity of 160 mPa · s (hereinafter referred to as “polyamic acid (I-1 About 3,700 g of a solution was obtained.

<Comparative substance synthesis example>

The reaction was performed with reference to literature (K. Hasegawa, Polymer Journal. Vol. 31, No. 2, 206 (1999)). In a nitrogen atmosphere, 3.1 g (10 mmol) of 4,4′-dibromobiphenyl and 1.86 g (20 mmol) of aniline were placed in a 300 ml three-necked flask and dissolved by adding 80 ml of toluene. Sodium-t-butoxide 5.8 (60 mmol), tris (dibenzylideneacetone) -dipalladium (Pd ₂ (dba) ₃ ) 0.46 g (0.5 mmol), 2,2′-bis (diphenylphosphino)- 0.91 g (1.5 mmol) of 1,1′-binaphthyl (BINAP) was added at room temperature. The reaction solution was stirred and reacted at 100 ° C. for 16 hours under nitrogen. Next, the reaction solution was returned to room temperature and washed with 2 liters of a mixed solution of ammonia water and methanol (ammonia water / methanol = 1/4 volume ratio) using a separatory funnel. The organic solvent layer was dehydrated with sodium sulfate and then concentrated with a rotary evaporator. The resulting crude product was purified by silica gel column chromatography to obtain 2.1 g of a comparative substance.

Example 1
The specific polyamic acid (B-1) and other polyimide (A-1) are mixed with γ-butyrolactone / N-methyl-2-pyrrolidone / butyl cellosolve so that polyimide: polyamic acid = 20: 80 (weight ratio). (Weight ratio 71/17/12), and 2 parts by weight of N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane is added to the polymer 100 to obtain a solid content of 3 A 0.5 wt% solution and a 6.0 wt% solution were made. Each solution was sufficiently stirred and then filtered using a filter having a pore size of 1 μm to prepare the liquid crystal aligning agent of the present invention.

Among the liquid crystal aligning agents, a solution having a solid content concentration of 3.5% by weight is applied on a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm using a spinner (number of rotations: 2,500 rpm, coating time: 1 minute) and dried at 200 ° C. for 1 hour to form a film having a dry film thickness of 0.08 μm. A rubbing machine having a roll in which a rayon cloth was wound around this film was subjected to a rubbing treatment at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / second, and a hair foot pushing length of 0.4 mm. Ultrasonic cleaning was performed for 1 minute in ultrapure water, followed by drying for 10 minutes in a 100 ° C. clean oven. Next, after applying an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm to the outer edges of the pair of transparent electrodes / transparent electrode substrates having the liquid crystal alignment film of the liquid crystal alignment film coated substrate, the liquid crystal alignment film The adhesive was cured by overlapping and pressing so that the surfaces were opposed. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) is filled between the substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive to produce the liquid crystal display element of the present invention. did. The voltage holding ratio evaluation and burn-in evaluation of the obtained liquid crystal display element were performed according to the method described above.
On the other hand, printability was evaluated according to the method described above using a solution having a solid content concentration of 6.0% by weight. Moreover, imidation rate evaluation was performed using the sample after printability evaluation.

Examples 2-13
The same procedure as in Example 1 was performed except that the specific polyimide, specific polyamic acid, other polyimide, and other polyamic acid were used in the composition ratios shown in Table 1 as shown in Table 1.

Comparative Examples 1-4
Other polyimides and other polyamic acids were prepared in the same procedure as in Example 1 except that the materials listed in Table 1 were used at the composition ratios in Table 1.

Comparative Examples 5-8
Other polyimides and other polyamic acids were used in the same procedure as in Example 1 except that the materials listed in Table 1 were used in the composition ratios in Table 1 and that 10 parts by weight of a comparative substance was added to 100 parts by weight of the polymer. I went there.

Explanatory drawing of the cell created for evaluation of the burn-in test. ¹ H-NMR spectrum diagram of diamine A-1. ¹ H-NMR spectrum diagram of diamine A-2.

Claims (7)

A liquid crystal comprising at least one polymer selected from a polyamic acid comprising a repeating unit represented by the following formula (I-1) and a polyimide comprising a repeating unit represented by the following formula (I-2): Alignment agent.

Here, P ¹ and P ² represent a tetravalent organic group, and Q ¹ and Q ² represent a divalent organic group including a structure represented by the following formula (1).

(Wherein R ₁ , R ₂ and R ₃ are each independently hydrogen, an alkyl group, an alkoxy group, or an aromatic group, R ₄ is hydrogen or an alkyl group, and m is 2. ) In the above formula (1), the liquid crystal aligning agent of claim 1 wherein R ₁ is hydrogen. In the above formula (1), the liquid crystal alignment agent according to claim 2 _{R 2} and _{R 3} are hydrogen. In the above formula (1), the liquid crystal aligning agent of claim 3 _{R 4} is a methyl group. The formula (I-1) in ^{P 1} and the formula (I-2) in claim 1 wherein at least a portion of ^{P 2} is derived from 2,3,5-tricarboxycyclopentylacetic dianhydride of The liquid crystal aligning agent in any one. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 and having an imidization ratio of 30 to 98%. A liquid crystal display element comprising the liquid crystal alignment film according to claim 1.

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