JP4788898B2 - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

  The present invention relates to a novel liquid crystal aligning agent and a liquid crystal display element. More specifically, the present invention relates to a novel liquid crystal aligning agent that has a novel pretilt angle manifesting component, gives a pretilt angle of 1 to 30 °, and does not cause defects due to liquid crystal injection, and a liquid crystal display element having a beautiful image .

  From the viewpoint of space saving and low power consumption, liquid crystal display elements such as liquid crystal displays have been developed since the first liquid crystal calculator was mass-produced. Watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, Applications in various fields such as digital cameras, mobile phones, various monitors, and LCD TVs are advancing, and active development is continuing. Conventionally, as a display method, a liquid crystal having positive dielectric anisotropy is used, and a TN (Twisted Nematic) method or a STN (Super Twisted) method in which liquid crystal molecules are driven from a parallel to a vertical direction with respect to a substrate surface by applying a voltage. Nematic) has been widely used. In recent years, in order to further improve the display quality of liquid crystal displays, an optically compensated bent (OCB) type liquid crystal display element having a small viewing angle dependency and excellent in high-speed response required for displaying moving picture images has been developed. Yes.

  In a liquid crystal display element, the alignment of liquid crystal is usually controlled by subjecting a liquid crystal alignment film formed of a liquid crystal alignment agent containing a polymer such as polyamic acid and / or polyimide to a rubbing treatment. As described in Patent Document 1, in a TN type or STN type liquid crystal display element, the liquid crystal alignment film may exhibit a high liquid crystal pretilt angle from the viewpoint of preventing display unevenness due to the occurrence of reverse tilt. It is requested. Further, as described in Patent Document 2, an OCB type liquid crystal display element also exhibits a high liquid crystal pretilt angle from the viewpoint of preventing a reduction in screen brightness due to a reverse transition from the bent type alignment to the splay alignment. It is requested. In the OCB type liquid crystal display element described in Patent Document 3, a TN type is used, as is the case with the orientation film SE7942 manufactured by Nissan Chemical Co., Ltd., which is usually used as an orientation film for a TN type liquid crystal display element. The liquid crystal alignment film used for liquid crystal display elements can also be used as an alignment film for OCB type liquid crystal display elements.

In the material design of the liquid crystal alignment film, in order to develop a high pretilt angle of the liquid crystal, a method in which a component having a bulky aliphatic hydrocarbon substituent (hereinafter referred to as a pretilt angle developing component) is usually introduced into the polymer Has been used. However, these bulky aliphatic hydrocarbon substituents have a problem of giving a stable high pretilt angle while reducing the affinity with the liquid crystal and reducing the wettability of the liquid crystal on the alignment film. Specifically, when the liquid crystal injection is performed by the vacuum injection method, the liquid crystal injection speed is remarkably reduced, so that the productivity of the cell production becomes very bad, and when the liquid crystal injection is performed by the ODF method, the liquid crystal dropping portion In addition, there is a problem that alignment unevenness occurs in a fusion part between liquid crystals and the like, resulting in a display defect of the liquid crystal display element. Therefore, in order to improve the above problem, development of a liquid crystal aligning agent that expresses a high pretilt angle of liquid crystal and has excellent paintability with liquid crystal has been desired.
JP-A-5-323327 JP 2003-279996 A JP 2004-272112 A

  The present invention has been made on the basis of the above circumstances. Therefore, an object of the present invention is to provide a liquid crystal aligning agent which gives a liquid crystal pretilt angle of 1 to 30 ° and is excellent in liquid crystal wettability. It is in.

According to the present invention, the above object of the present invention is as follows.
Following formula (1)

(In the formula, R ₁ is a hydrogen atom, R ₂ is water atom, a halogen atom, a substituted or unsubstituted 1-30 carbon atoms hydrocarbon group, a substituted or unsubstituted 1 to 30 carbon atoms a hydrocarbon -X- group or polar group, -X- is a linking group. However, the five R ₂ is at least one fluorine-substituted five R ₂ was Yokuma be the same or different A first diamine represented by a hydrocarbon group having 1 to 30 carbon atoms or a fluorine-substituted hydrocarbon-X-group having 1 to 30 carbon atoms),
H ₂ N—R ₃ —NH ₂ (2)
(Wherein R ₃ is a divalent organic group),
A second diamine different from the first diamine, and the following formula (3)

(Wherein R ₄ is a tetravalent organic group),
A liquid crystal aligning agent comprising at least one of a polyamic acid obtained by reacting with a tetracarboxylic dianhydride represented by the formula (1) and an imidized polymer produced by dehydrating and ring-closing the polyamic acid. Is achieved.

  Further, according to the present invention, the above object of the present invention is achieved by a liquid crystal display device comprising a liquid crystal alignment film formed from the above liquid crystal aligning agent.

  According to the liquid crystal aligning agent of this invention, the liquid crystal aligning film which gives the pretilt angle of 1-30 degrees and is excellent in the wettability of a liquid crystal is obtained. Especially the liquid crystal aligning agent of this invention can be used suitably for liquid crystal display elements, such as TN mode, STN mode, and OCB mode.

[Polyamic acid and imidized polymer]
Hereinafter, the present invention will be described in detail. The polyamic acid used in the present invention is obtained by polyaddition reaction of the diamine represented by the above formula (1) and the above formula (2) and the tetracarboxylic dianhydride represented by the above formula (3). . The imidized polymer used in the present invention can be obtained by dehydrating and ring-closing the polyamic acid.

[Diamine]
The liquid crystal aligning agent of this invention expresses a desired pretilt angle by copolymerizing the diamine represented by said Formula (1) as diamine, and expresses the performance excellent in the wettability of the liquid crystal.
In the present invention, the ratio of the first diamine compound represented by the above formula (1) is preferably based on the total amount of the diamine represented by the above formula (1) and the diamine represented by the above formula (2). It is 1-10 mol%, More preferably, it is 1-8 mol%, Most preferably, it is 1-5 mol%. If the proportion of the first diamine compound represented by the above formula (1) is less than 1 mol%, sufficient pretilt angle and liquid crystal wettability cannot be obtained, and if it exceeds 10 mol%, the pretilt angle becomes too high. When forming the alignment film, poor coating properties such as pinholes may occur.

Formula Te (1) odor, represented by R _2, a halogen atom; an oxygen atom, a nitrogen atom, a sulfur atom or substituted or may have a linking group containing a silicon atom or an unsubstituted carbon atoms 1 30 hydrocarbon groups; and polar groups will be described.
As a halogen atom, a fluorine atom, a chlorine atom, and a bromine atom are mentioned, for example.
Examples of the hydrocarbon group having 1 to 30 carbon atoms include alkyl groups such as methyl group, ethyl group and propyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group and allyl group; Group, alkylidene group such as propylidene group; aromatic groups such as phenyl group, naphthyl group, anthracenyl group, biphenyl group, and fluorenyl group. A hydrogen atom bonded to a carbon atom in these groups may be substituted with, for example, a halogen atom such as fluorine, chlorine or bromine and a cyano group.

Further, the hydrocarbon group of the above substituted or unsubstituted 1 to 30 carbon atoms is benzene ring that appears in equation (1) (case of R ₂₎ and carbon atoms (for R _1), They may be directly bonded or may be bonded via a linking group (—X—). The linking group (—X—) is represented by, for example, a divalent hydrocarbon group having 1 to 10 carbon atoms, for example, — (CH ₂ ) _m — (wherein m is an integer of 1 to 10). An alkylene group, an oxygen atom, a nitrogen atom, a sulfur atom or a linking group containing a silicon atom (for example, a carbonyl group (—CO—), a carbonyloxy group (—COO—), a sulfonyl group (—SO ₂ —), a sulfonyloxy group) Group (—SO ₂ —O—), ether bond (—O—), thioether bond (—S—), imino group (—NH—), amide bond (—NHCO—), siloxane bond (—Si (R)) ₂ O-) (wherein, R is an alkyl group such as a methyl group or an ethyl group); or a combination of two or more of these in combination.
Examples of the polar group include a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a cyano group, a nitro group, an amide group, and an imino group (= NH), triorganosiloxy group, triorganosilyl group, amino group, acyl group, alkoxysilyl group, sulfonic acid group (—SO ₃ H), sulfino group (—SO ₂ H), carboxyl group and the like.

  More specifically, examples of the alkoxy group include methoxy group and ethoxy group; examples of the alkylcarbonyloxy group include acetoxy group and propionyloxy group; examples of the arylcarbonyloxy group include Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group; examples of the aryloxycarbonyl group include a phenoxycarbonyl group, a naphthyloxycarbonyl group, and a fluorenyl group. Examples of the triorganosiloxy group include trimethylsiloxy group and triethylsiloxy group; examples of the triorganosilyl group include trimethylsilyl group. Examples of amino groups include secondary amino groups and tertiary amino groups, and examples of alkoxysilyl groups include trimethoxysilyl groups and triethoxysilyl groups. Group and the like.

However, the formula Te (1) odor, Ru substituents der containing five least one fluorine atom substituent represented by R _2. Such a group containing a fluorine atom in R ₂ is preferably a fluorinated alkyl group, in which case the fluorinated alkyl group preferably has 1 to 40 carbon atoms, more preferably 2 to 25 carbon atoms, and particularly preferably. Ru 5-15 der. If the number of carbon atoms in the above group containing a fluorine atom in R ₂ (fluorinated alkyl group) is small, a sufficient pretilt angle cannot be expressed, and if the number of carbon atoms is 40 or more, pinholes are generated during the formation of the alignment film. Such as poor applicability may occur. Also, a substituent containing a fluorine atom in R ₂ (fluorinated alkyl group) represents a linear, branched, may be any cyclic structure, that in view of excellent liquid crystal pretilt angle expressing a linear preferable.

Specific examples of the diamine represented by the above formula (1) include the compounds described below.
4,4′-diamino-4 ″ -fluorotriphenylmethane represented by the following formula (1-1)

4,4'-diamino-4 "-trifluoromethyltriphenylmethane represented by the following formula (1-2)

4,4'-diamino-4 "-trifluoromethoxytriphenylmethane represented by the following formula (1-3)

4,4′-diamino-3 ″, 5 ″ -bistrifluoromethyltriphenylmethane represented by the following formula (1-4)

4,4'-diamino-4 "-pentafluoroethyltriphenylmethane represented by the following formula (1-5)

4,4'-diamino-4 "-pentafluoropropyltriphenylmethane represented by the following formula (1-6)

4,4'-diamino-4 "-nonafluorobutyltriphenylmethane represented by the following formula (1-7)

4,4'-diamino-4 "-undecafluoropentyltriphenylmethane represented by the following formula (1-8)

4,4'-diamino-4 "-tridecafluorohexyltriphenylmethane represented by the following formula (1-9)

4,4'-diamino-4 "-pentadecafluoroheptyltriphenylmethane represented by the following formula (1-10)

4,4'-diamino-4 "-heptadecafluorooctyltriphenylmethane represented by the following formula (1-11)

4,4′-diamino-4 ″ -nonadecafluorononyltriphenylmethane represented by the following formula (1-12)

4,4'-diamino-4 "-henicosafluorodecyltriphenylmethane represented by the following formula (1-13)

  The primary amine represented by the above formula (1) can be used alone or in combination of two or more.

  Among these, as the first diamine, 4,4′-diamino-4 ″ -undecafluoropentyltriphenylmethane represented by the above formula (1-8), 4,4 represented by the above formula (1-9). '-Diamino-4 ″ -tridecafluorohexyltriphenylmethane, 4,4′-diamino-4 ″ -pentadecafluoroheptyltriphenylmethane represented by the above formula (1-10), 11) 4,4′-diamino-4 ″ -heptadecafluorooctyltriphenylmethane, 4,4′-diamino-4 ″ -nonadecafluorononyltri represented by the above formula (1-12) Phenylmethane, 4,4′-diamino-4 ″ -henicosafluorodecyltriphenylmethane represented by the above formula (1-13) is preferable, and in particular, the above formula (1 4,4'-diamino-4 '' represented by 11) - heptadecafluorooctyl triphenylmethane is preferable in terms of forming the alignment agent having excellent coating properties at the time of forming an alignment film and the liquid crystal pretilt angle expressing.

Examples of the second diamine compound represented by the above formula (2) include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, and 4,4′-diamino. Diphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 2,2′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene 3,3′-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-amino) Phenyl) -1,3,3-trimethylindane, 3,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-di Minobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2- Bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 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-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- Phenylene isopropylidene) bisaniline, 4,4 ′-(m-phenylene isopropylidene) bisaniline, 2,2′-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4 '-Diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl, 1,3-bis (4- Aromatic diamines such as aminophenoxy) -2,2-dimethylpropane, 4,4′-bis (4-aminophenoxy) biphenyl;
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 Intramolecular, such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine and compounds represented by the following formulas (4) and (5) A diamine having two primary amino groups and a nitrogen atom other than the primary amino group;

(In the formula, R ₅ represents a monovalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine, and X represents a divalent organic group.)

(Wherein R ₆ represents a divalent organic group having a ring structure containing a nitrogen atom selected from pyridine, pyrimidine, triazine, piperidine and piperazine)
Mono-substituted phenylenediamine represented by the following formula (6);

(Wherein R ₇ represents a divalent organic group selected from —O—, —COO—, —OCO—, —NHCO—, —CONH— and —CO—, and R ₈ represents a steroid skeleton, A monovalent organic group having at least one group selected from a fluoromethyl group, a trifluoromethoxy group, and a fluoro group, or an alkyl group having 6 to 30 carbon atoms.)
1,3-bis (aminomethyl) cyclohexane, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, tricyclo [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine, 4,4′-methylenebis (cyclohexylamine), etc. Aliphatic and alicyclic diamines; diaminoorganosiloxanes represented by the following formula (7);

(In the formula, R ₉ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ₉ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) It is an integer. These secondary amines may be used alone or in combination of two or more.

  Among these, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 9, 9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2 , 2-bis (4-aminophenyl) hexafluoropropane, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-diamino-2, 2′-bis (trifluoromethyl) biphenyl, 4,4′-diamino-2,2′-dimethylbiphenyl, 2,6- Diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, a compound represented by the following formula (4-1) among the compounds represented by the above formula (4), the above Of the compounds represented by the formula (5), the compounds represented by the following formula (5-1), and among the compounds represented by the above formula (6), the following formulas (6-1) and (6-2) , (6-3), (6-4), 1,3-bis (aminomethyl) cyclohexane, 1,4-cyclohexanediamine, 4,4′-methylenebis (cyclohexylamine), the above Of the compounds represented by the formula (7), 3,3 ′-(tetramethyldisiloxane-1,3-diyl) bis (propylamine) represented by the following formula (7-1) is preferable.

  More particularly preferred are p-phenylenediamine, 4,4′-diaminodiphenylmethane, 2,2′-dimethyl-4,4′-diaminobiphenyl, 1,3′-bis (4-aminophenoxy) -2, 2-dimethylpropane, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 3,3 ′-(tetramethyldisiloxane-1,3-diyl) bis (propylamine), 1,3-bis (amino) Mention may be made of methyl) cyclohexane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl.

[Tetracarboxylic dianhydride]
Examples of tetracarboxylic dianhydride include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane. Tetracarboxylic 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, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6- Recarboxynorbornane-2-acetic acid 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) -naphth [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), the following formula (8 ) And aliphatic and alicyclic tetracarboxylic dianhydrides such as compounds represented by (9);

Wherein R ₁₀ and R ₁₂ represent a divalent organic group having an aromatic ring, R ₁₁ and R ₁₃ represent a hydrogen atom or an alkyl group, and a plurality of R ₁₁ and R ₁₃ are the same. But it may be different.)

  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′-bi (3,4-Dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid Dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenyl) Phthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (an Hydrotrimellitate), 1,4-butanediol-bis (anhydrotrimellitate), 1,6-hexa Diol-bis (anhydro trimellitate), 1,8-octanediol-bis (anhydro trimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydro trimellitate), below Aromatic tetracarboxylic dianhydrides such as compounds represented by formulas (10) to (13) can be given. These may be used alone or in combination of two or more.

  Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- ( 2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic 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-8-methyl-5- (tetrahydro-2,5 − Oxo-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 Acid dianhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride Of the anhydrides, compounds represented by the above formula (8) Among the compounds represented by the formulas (8-1) to (8-3) and the compound represented by the above formula (9), the compound represented by the following formula (9-1) has good liquid crystal orientation. It is preferable from the viewpoint that can be expressed. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5 Cyclohexanetetracarboxylic 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, 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'-Geo ), Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride and represented by the following formula (8-1) can be mentioned compounds.

  These tetracarboxylic dianhydrides are used alone or in combination of two or more.

<Synthesis of polyamic acid>
The ratio of the tetracarboxylic dianhydride and the diamine compound used in the polyamic acid synthesis reaction of the present invention is such that the acid anhydride group of the tetracarboxylic dianhydride is equivalent to 1 equivalent of the amino group contained in the diamine compound. Is preferably a ratio of 0.2 to 2 equivalents, more preferably a ratio of 0.3 to 1.2 equivalents.
The synthetic reaction of polyamic acid is preferably carried out in an organic solvent under a temperature condition of -20 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, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide And aprotic polar solvents such as γ-butyrolactone, tetramethylurea and hexamethylphosphortriamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenol. The amount of the organic solvent used (a) is 0.1 to 30% by weight based on the total amount (a + b) of the reaction solution when the total amount (b) of the tetracarboxylic dianhydride and the diamine compound is used. It is preferable that the amount is small.

<Poor solvent>
In addition, the said organic solvent can use together the alcohol, ketone, ester, ether, halogenated hydrocarbon, hydrocarbons, etc. which are poor solvents of a polyamic acid in the range from 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, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, diacetone alcohol, 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, propylene carbonate, diethyl oxalate, diethyl malonate, diethyl ether , Ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol- -Propyl ether, ethylene glycol monobutyl 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, tetrahydrofuran , Dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like. These poor solvents can be used alone or in combination of two or more.
As described above, a reaction solution obtained by dissolving polyamic acid is obtained. And after pouring this reaction solution in a lot of poor solvents and obtaining a deposit, polyamic acid can be obtained by drying this deposit under reduced pressure. The polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and then precipitating with a poor solvent once or several times.

<Imidized polymer>
The imidized polymer of the present invention can be synthesized by dehydrating and ring-closing the polyamic acid. The imidized polymer referred to here includes a partially imidized polymer obtained by partially imidizing the polyamic acid and a polymer imidized by 100%. Hereinafter, these are collectively referred to as an “imidized polymer”. Describe.
The imidation ratio in the imidized polymer used in the present invention is preferably 10 to 100%, more preferably 30 to 98%, and particularly preferably 45 to 97%. Here, the “imidation ratio” is the percentage of the number of repeating units that form an imide ring with respect to the total number of repeating units in the polymer. At this time, a part of the imide ring may be an isoimide ring.

As a method for synthesizing an imidized polymer, (i) a method of synthesizing the polyamic acid by dehydrating and cyclizing by heating, (ii) dissolving the polyamic acid in an organic solvent, a dehydrating agent and A method of synthesizing by dehydrating and ring-closing by adding a dehydrating ring-closing catalyst and heating as necessary; (iii) mixing a tetracarboxylic dianhydride, a diamine compound and a diisocyanate compound, and heating if necessary , A method of synthesis by condensation is used, and a polymer having a desired imidization ratio can be obtained by appropriately controlling the reaction conditions.
In the method (i), the reaction temperature is preferably 300 ° C. or less, more preferably 100 to 250 ° C. When the reaction temperature exceeds 300 ° C., the molecular weight of the imidized polymer obtained may decrease.

  On the other hand, as the dehydrating agent used in the method (ii), acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.2 to 20 mol with respect to 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, the dehydrating agent and the dehydrating ring closure catalyst are not limited to these examples. Moreover, it is preferable that the usage-amount of an imidation catalyst shall be 0.1-10 mol with respect to 1 mol of dehydrating agents to be used. In addition, as an organic solvent used for reaction of dehydration ring closure, the same organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. And the reaction temperature of dehydration ring closure becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 60-150 degreeC. In addition, the imidized polymer can be purified by performing the same operation as the polyamic acid purification method on the reaction solution thus obtained.

  Specific examples of the diisocyanate compound used in the reaction (iii) include aliphatic diisocyanates such as hexamethylene diisocyanate; cyclohexane-1,2-diisocyanate, 1-methylcyclohexane-2,4-diisocyanate, 1,2-dimethyl. Cyclohexane-ω, ω′-diisocyanate, 1,4-dimethylcyclohexane-ω, ω′-diisocyanate, isophorone diisocyanate, 1,3,5-trimethyl-2-propylcyclohexane-1ω, 2ω′-diisocyanate, dicyclohexylmethane-4 , 4'-diisocyanate, etc .; diphenylmethane-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl 2,6-phenylene diisocyanate, aromatic diisocyanates such as diisocyanate represented by the following (14) to (17).

  Among these, preferred are dicyclohexylmethane-4,4′-diisocyanate, diphenylmethane-4-, 4 ′ diisocyanate, 1-methyl-2,4-phenylene diisocyanate, and 1-methyl-2,6-phenylene diisocyanate. . These can be used alone or in combination of two or more. In addition, a catalyst is not particularly required for the reaction (iii), and the reaction temperature is preferably 50 to 200 ° C, more preferably 100 to 160 ° C.

<End-modified polymer>
The polyamic acid and the imidized polymer constituting the liquid crystal aligning agent of the present invention may be of a terminal modified type having a controlled molecular weight. By using this terminal-modified polymer, the coating properties of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. Such a terminal-modified type can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when synthesizing the 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 the monoamine compound include aniline, cyclohexylamine, p-ethylaniline, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosyl An amine etc. can be mentioned. Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Logarithmic viscosity of polymer>
The logarithmic viscosity (η _ln ) of the polyamic acid and imidized polymer obtained as described above is preferably 0.05 to 10 dl / g, more preferably 0.05 to 5 dl / g.
The value of the logarithmic viscosity (η _ln ) in the present invention is determined by measuring the viscosity at 30 ° C. for a solution having a concentration of 0.5 g / 100 ml using N-methyl-2-pyrrolidone as a solvent. ).

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention is preferably constituted by constituting the polyamic acid and the imidized polymer dissolved in an organic solvent. The liquid crystal aligning agent of the present invention does not contain the diamine structure represented by the above formula (1) at the time of adjusting the aligning agent in order to improve the properties such as voltage holding ratio, seizure resistance (residual DC) and the coating properties Other polyamic acids and / or other imidized polymers may be added. The other polyamic acid and / or other imidized polymer to be added may be one kind or plural kinds depending on the purpose, and usually other polyamic acid is preferable, and 1,2,3,4-cyclobutanetetracarboxylic is particularly preferable. Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tri Carboxycyclopentyl 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, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3 -Dione, One or more selected from oxabicyclo [3.2.1] octane-2,4-dione-6-spiro-3 ′-(tetrahydrofuran-2 ′, 5′-dione), pyromellitic dianhydride Acid dianhydride and p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 9 , 9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-Diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 3,3- (te La methyl-1,3-diyl) bis (propylamine) Other polyamic acid obtained by reacting one or more diamines selected from the preferred. A polyamic acid and / or an imidized polymer (referred to as a polymer “X”) containing a diamine structure represented by the above formula (1) and a diamine structure represented by the above formula (1) The mixing ratio of the polyamic acid and / or other imidized polymer (hereinafter referred to as polymer “Y”) is preferably in the range of X: Y = 10: 90 to 90:10 by weight ratio. More preferably, the range is X: Y = 15: 85 to 60:40, and particularly preferably the range is X: Y = 20: 80 to 50:50.
The temperature at which the liquid crystal aligning agent of the present invention is prepared is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.

  As an organic solvent which comprises the liquid crystal aligning agent of this invention, the same thing as the solvent illustrated as what is used for the synthesis reaction of a polyamic acid can be mentioned. Among these, a solvent having a boiling point of 160 ° C. or more is preferable from the viewpoint of printability. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, phenol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, diacetone alcohol, butyl lactate, butyl acetate, ethyl ethoxypropionate, propylene carbonate, oxalic acid Diethyl, diethyl malonate, ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl And ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 1,4-dichlorobutane, o-dichlorobenzene and the like. N-methyl-2-pyrrolidone, γ-butyrolactone, di Acetone alcohol, ethylene glycol monobutyl ether (butyl cellosolve), propylene carbonate, and diethylene glycol diethyl ether are particularly preferred.

  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. The liquid crystal aligning agent is applied to the substrate surface to form a coating film that becomes a liquid crystal alignment film. However, when the solid content concentration is less than 1% by weight, the film thickness of this coating film is too small and good. If a solid liquid crystal alignment film cannot be obtained and 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. The viscosity of the agent increases, resulting in poor coating properties.

  The viscosity of the liquid crystal aligning agent of the present invention (viscosity measured at 25 ° C. using a rotational viscometer for the liquid crystal aligning agent) needs to be appropriately adjusted according to the method of applying the aligning agent. The viscosity of the liquid crystal aligning agent is usually 3 to 100 mPa · s, preferably 4 to 50 mPa · s, and particularly preferably 5 to 35 mPa · s.

  The liquid crystal aligning agent of the present invention may contain a functional silane-containing compound or an epoxy group-containing compound from the viewpoint of improving the adhesion to the substrate surface. 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, 3-glycidoxypropyltrimethoxysilane and the like can be mentioned.

  Examples of the epoxy group-containing compound 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, 1, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentylglycol 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 , And the like as preferred 4'-diaminodiphenylmethane. The compounding ratio of these functional silane-containing compounds and epoxy group-containing compounds is 100 parts by weight of polyamic acid and / or imidized polymer (if other polyamic acid and other imidized polymer are also used, these are added. Preferably 60 parts by weight or less, more preferably 50 parts by weight or less.

<Liquid crystal display element>
The liquid crystal display element of the present invention can be produced, for example, by 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 a method such as a roll coater method, a spinner method, a printing method, an ink jet method, etc. 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. Can be used. For patterning these transparent conductive films, a photo-etching method or a method using a mask in advance is used. The reflective electrode can be made of a metal such as Al or Ag, or an alloy containing these metals, but is not limited thereto as long as it has a sufficient reflectivity. When applying the liquid crystal aligning agent, a functional silane-containing compound, a functional titanium-containing compound, or the like is provided on the surface of the substrate in order to further improve the adhesion between the substrate surface and the transparent conductive film or reflective electrode and the coating film. Can also be applied in advance. After application of the liquid crystal aligning agent, preheating (pre-baking) is usually 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 thermally imidizing the polyamic acid into polyimide. 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 an alignment film by removing the organic solvent after coating, and further proceeds with dehydration ring closure by heating, and more imide It can also be set as a coated film. The film thickness of the formed coating film is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

(2) A rubbing process is performed in which the formed coating surface is rubbed in a certain direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film. In addition to the method by rubbing treatment, a method of controlling the alignment ability by irradiating the surface of the coating film with polarized ultraviolet light can be applied. In order to remove fine powder (foreign matter) generated during the rubbing process and clean the surface of the coating film, the formed liquid crystal alignment film may be washed with isopropyl alcohol and / or pure water or the like. preferable. Further, by partially irradiating the liquid crystal alignment film formed by 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 a liquid crystal alignment film that has been subjected to a process for changing the pretilt angle or a rubbing process as disclosed in JP-A-5-107544, which is different from the previous rubbing process. After performing the rubbing treatment in the direction, it is possible to improve the visual field characteristics of the liquid crystal display element by removing the resist film and changing the 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. And a liquid crystal display element is obtained by arrange | positioning a polarizing plate to the outer surface of a liquid crystal cell, ie, the outer surface side of each board | substrate which comprises a liquid crystal cell.
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, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane. Type liquid crystal, cubane type liquid crystal 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. The pretilt angle, voltage holding ratio, liquid crystal paintability and printability in Examples and Comparative Examples were evaluated by the following methods.

[Pretilt angle]
In accordance with the method described in TJScheffer, et.al., J.Appl.Phys., Vol.19, 2013 (1980), the measurement was performed by the crystal rotation method using He-Ne laser light. Here, the pretilt angle is defined as an angle at which the alignment direction of the liquid crystal molecules is inclined from the substrate surface.

[Voltage holding ratio]
A voltage of 5 V was applied to the liquid crystal display element with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio after 167 milliseconds from release of application was measured. The measuring device used was VHR-1 manufactured by Toyo Corporation. The case where the voltage holding ratio was 98.5% or more was judged as good, and the other cases were judged as bad.

[Liquid crystal wettability]
Each liquid crystal aligning agent of the present invention prepared in the following Examples and Comparative Examples was applied using a spinner on a transparent conductive film made of an ITO film provided on one surface of a glass substrate, and then on a hot plate at 80 ° C. for 1 minute. Was then dried and then baked on a hot plate at 210 ° C. for 10 minutes to prepare a liquid crystal alignment film having a thickness of 60 nm. Liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) is dropped on each alignment film, and when the contact angle between the liquid crystal and the alignment film measured 30 seconds after dropping is 14 degrees or less, the wettability is good and the contact angle is 14 degrees. When it became larger, it was judged that the paintability was poor. The results of evaluating the liquid crystal paintability of each alignment agent are summarized in Table 1.

[Printability test]
Each liquid crystal aligning agent of the present invention adjusted in the following examples and comparative examples (total solid content concentration adjusted to 6.9%) was used with a liquid crystal alignment film printer (Nissha Printing Co., Ltd.). Then, an ITO film having a thickness of 200 nm and a width of 20 μm is applied to the transparent electrode surface of the glass substrate with a transparent electrode formed in stripes at intervals of 100 μm, and pre-dried at 80 ° C. for 1 minute on a hot plate. Then, after baking on a hot plate at 210 ° C. for 10 minutes to form a liquid crystal alignment film, the periphery and center of this liquid crystal alignment film are observed with a microscope with a magnification of 20 times, and there is no coating unevenness. A case where there was “good” and coating unevenness was judged as “bad”.
The results of evaluating the printability of each aligning agent are summarized in Table 1.

Synthesis Example 1 (Synthesis of polyimide A-1)
1,3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan as tetracarboxylic dianhydride -1,3-dione 11.7069 g (0.0372 mol), 2,3,5-tricarboxycyclopentyl acetic anhydride 8.3168 g (0.0371 mol), p-phenylenediamine 7.0010 g as a diamine compound ( 0.0647 mol), 1.0275 g (0.0015 mol) of 4,4′-diamino-4 ″ -n-heptadecafluorooctyltriphenylmethane represented by the formula (1-11), 3, 3 '-(Tetramethyldisiloxane-1,3-diyl) bis (propylamine) 1.8440 g (0.0074 mol) and a monoamine for terminal modification Phosphorus 0.1037g of (0.0011 mol) was dissolved in N- methyl-2-pyrrolidone 70 g, it was reacted for 6 hours at 60 ° C.. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 24 hours to obtain 27.3 g of a polyamic acid having a logarithmic viscosity of 0.60 dl / g. 25 g of the resulting polyamic was dissolved in 225 g of N-methyl-2-pyrrolidone, 24.5 g of pyridine and 25.3 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours. And 21.5 g of polyimide having a logarithmic viscosity of 0.58 dl / g (referred to as “polyimide A-1”) was obtained.

Synthesis Example 2 (Synthesis of polyimide A-2)
1,3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan as tetracarboxylic dianhydride -1,3-dione 11.3781 g (0.0362 mol), 2,3,5-tricarboxycyclopentyl acetic acid dianhydride 8.0832 g (0.0361 mol), and p-phenylenediamine 6.6484 g as a diamine compound ( 0.0615 mol), 4,4′-diamino-4 ″ -n-heptadecafluorooctyltriphenylmethane represented by the above formula (1-11) 1.9974 g (0.0029 mol), 3, 3 '-(Tetramethyldisiloxane-1,3-diyl) bis (propylamine) 1.7922 g (0.0072 mol) and a monoamine for terminal modification Phosphorus 0.1007g of (0.0011 mol) was dissolved in N- methyl-2-pyrrolidone 70 g, it was reacted for 6 hours at 60 ° C.. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 24 hours to obtain 27.0 g of a polyamic acid having a logarithmic viscosity of 0.59 dl / g. 25 g of the resulting polyamic was dissolved in 225 g of N-methyl-2-pyrrolidone, 23.8 g of pyridine and 24.6 g of acetic anhydride were added, dehydration and ring closure were performed at 110 ° C. for 4 hours, precipitation, washing, And 20.8 g of polyimide having a logarithmic viscosity of 0.57 dl / g (referred to as “polyimide A-2”) was obtained.

Synthesis Example 3 (Synthesis of polyamic acid B-1)
196.12 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride and 2,2′-dimethyl-4,4′-diaminobiphenyl 212 as diamine compound .3 g (1.0 mol) was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 40 ° C. for 3 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reactive organism. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 24 hours to obtain 390 g of a polyamic acid having a logarithmic viscosity of 0.91 dl / g (referred to as “polyamic acid B-1”).

Comparative Synthesis Example 1 (Synthesis of polyimide A-3)
1,3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan as tetracarboxylic dianhydride -1,3-dione 11.6432 g (0.0370 mol), 2,3,5-tricarboxycyclopentyl acetic acid dianhydride 8.2715 g (0.0369 mol), p-phenylenediamine 6.9429 g as a diamine compound ( 0.0642 mol), 3,6-bis (4-aminobenzoyloxy) cholestane 0.7117 g (0.0011 mol) represented by the following formula (18), 3,3 ′-(tetramethyldisiloxane-1) , 3-Diyl) bis (propylamine) 1.8340 g (0.0074 mol) and stearylamine 0.596 as a monoamine for terminal modification g (0.0022 mol) was dissolved in N- methyl-2-pyrrolidone 70 g, and allowed to react for 18 hours at 60 ° C.. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 24 hours to obtain 25.8 g of polyamic acid having a logarithmic viscosity of 0.57 dl / g. 25 g of the resulting polyamic was dissolved in 225 g of N-methyl-2-pyrrolidone, 24.4 g of pyridine and 25.2 g of acetic anhydride were added, and the mixture was dehydrated and closed at 110 ° C. for 4 hours. And 19.8 g of polyimide having a logarithmic viscosity of 0.55 dl / g (referred to as “polyimide A-3”) was obtained.

Comparative Synthesis Example 2 (Synthesis of polyimide A-4)
As a tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride 19.8674 g (0.0886 mol), p-phenylenediamine 9.4403 g (0.0873 mol) as a diamine compound, 19) 3,5-diaminobenzoic acid = cholesta-5-en-3-yl 0.6923 g (0.0013 mol) was dissolved in N-methyl-2-pyrrolidone 70 g, and the mixture was heated at 60 ° C. for 4 hours. Reacted. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 24 hours to obtain 26.4 g of a polyamic acid having a logarithmic viscosity of 0.65 dl / g. 25 g of the obtained polyamic was dissolved in 225 g of N-methyl-2-pyrrolidone, 29.2 g of pyridine and 22.6 g of acetic anhydride were added, and dehydration was carried out at 110 ° C. for 4 hours. And 18.8 g of polyimide having a logarithmic viscosity of 0.62 dl / g (referred to as “polyimide A-4”) was obtained.

Example 1
The polyimide (A-1) obtained in Synthesis Example 1 and the polyamic acid (B-1) obtained in Synthesis Example 3 were converted into polyimide (A-1): polyamic acid (B-1) = 20: 80 (weight). Ratio) and dissolved in a mixed solvent of γ-butyrolactone / N-methyl-2-pyrrolidone / ethylene glycol monobutyl ether (solvent weight ratio 71/17/12), and further, N, N, N ′, N′— Tetraglycidyl-4,4′-diaminodiphenylmethane is 2% by weight based on the total amount of polyimide (A-1) and polyamic acid (B-1), and 3-glycidoxypropyltrimethoxysilane is polyimide (A-1). ) And polyamic acid (B-1) in an amount of 1% by weight, respectively, to obtain a liquid crystal aligning agent having a total solid content concentration of 3.5% by weight (however, the printability test is carried out as described above) Total solid content was adjusted to a liquid crystal aligning agent of 6.9 wt% in). This was sufficiently stirred and then filtered using a filter having a pore diameter of 1 μm to prepare the liquid crystal aligning agent of the present invention. The liquid crystal aligning agent is applied onto a transparent conductive film made of an ITO film provided on one surface of a glass substrate using a spinner, preliminarily dried at 80 ° C. for 1 minute on a hot plate, and then on the hot plate. By baking at 210 ° C. for 10 minutes, a transparent electrode substrate having a liquid crystal alignment film with a film thickness of 60 nm was produced. A rubbing machine having a roll in which a rayon cloth was wound around the coating film was rubbed once with a roll rotation speed of 400 rpm, a stage moving speed of 30 mm / second, and a limb pushing length of 0.4 mm. The liquid crystal alignment film coated substrate was ultrasonically cleaned in pure water for 1 minute, and then dried in a clean oven at 100 ° C. for 10 minutes. 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 through the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, and polarizing plates are formed on both sides of the substrate. Were bonded together to produce a liquid crystal display element. Table 1 shows the results of evaluating the pretilt angle and voltage holding ratio of the obtained liquid crystal display element.

Example 2
A liquid crystal display device was obtained in the same manner as in Example 1 except that the polyimide (A-2) obtained in Synthesis Example 2 was used instead of the polyimide (A-1). Table 1 shows the results of evaluating the pretilt angle and voltage holding ratio of the obtained liquid crystal display element.

Comparative Example 1
A liquid crystal display device was obtained in the same manner as in Example 1 except that polyimide (A-3) obtained in Comparative Synthesis Example 1 was used instead of polyimide (A-1). Table 1 shows the results of evaluating the pretilt angle and voltage holding ratio of the obtained liquid crystal display element.

Comparative Example 2
A liquid crystal display device was obtained in the same manner as in Example 1 except that only polyimide (A-4) obtained in Comparative Synthesis Example 1 was used instead of polyimide (A-1) and polyamic acid (B-1). . Table 1 shows the results of evaluating the pretilt angle and voltage holding ratio of the obtained liquid crystal display element.

  The liquid crystal alignment film obtained from the liquid crystal aligning agent obtained in Example 1 and Example 2 from Table 1 exhibits a high pretilt angle and has better liquid crystal coating properties than those obtained in Comparative Examples. It is clear. The pretilt angle and liquid crystal coatability of the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention can be adjusted by selecting the structure of the diamine containing a fluorine atom represented by the formula (1) and the copolymerization composition of the monomer. it is obvious. As described above, according to the present invention, it is possible to provide a liquid crystal aligning agent that exhibits a desired high pretilt angle and that has excellent liquid crystal wettability, and a liquid crystal display element that includes the alignment film and has a beautiful image. is there.

Claims (6)

Following formula (1)

(In the formula, R ₁ is a hydrogen atom, and R ₂ is water atom, a halogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon atoms from 1 to 30 represent hydrocarbon -X- group or polar group, -X- is a linking group. However, the five R ₂ is five least one fluorine R ₂ was Yokuma be the same or different A first diamine represented by a substituted hydrocarbon group having 1 to 30 carbon atoms or a fluorine-substituted hydrocarbon group having 1 to 30 carbon atoms-X- group),
H ₂ N—R ₃ —NH ₂ (2)
(Wherein R ₃ is a divalent organic group),
A second diamine different from the first diamine, and the following formula (3)

(Wherein R ₄ is a tetravalent organic group),
A liquid crystal aligning agent comprising at least one of a polyamic acid obtained by reacting with a tetracarboxylic dianhydride represented by the formula (1) and an imidized polymer produced by dehydrating and ring-closing the polyamic acid. . In the formula (1), the liquid crystal alignment agent according to Claim 1 group represented by R ₂ is 2 or more fluorinated alkyl group carbon atoms. The liquid crystal aligning agent according to claim 1 or 2, wherein the molar ratio of the first diamine / second diamine is in the range of 1/99 to 10/90. The tetracarboxylic dianhydride represented by the above formula (3) is 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl. -1,2,3,4-cyclobutanetetracarboxylic 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-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1 , 2-c] furan-1,3-dione, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride or pyromellitic dianhydride according to claim 1. The liquid crystal aligning agent of description. The liquid crystal aligning agent as described in any one of Claims 1-4 used for TN mode, STN mode, or OCB mode. A liquid crystal display element comprising a liquid crystal alignment film formed from the liquid crystal aligning agent according to claim 1.