JP2008299317A - Vertical alignment type liquid crystal aligning agent and liquid crystal display element - Google Patents

Abstract

（Ｐ¹、Ｐ²は酸由来の基、Ｑ¹、Ｑ²はジアミン由来の基。）
【選択図】なしA vertical alignment type liquid crystal aligning agent and a liquid crystal display element excellent in printability and vertical alignment are provided.
A polymer comprising a repeating unit represented by formula (I-1) or formula (I-2), wherein Q ¹ and Q ² contain a repeating unit having a divalent organic group, and It contains a specific mixed solvent.

(P ¹ and P ² are groups derived from an acid, and Q ¹ and Q ² are groups derived from a diamine.)
[Selection figure] None

Description

  The present invention relates to a vertical alignment liquid crystal aligning agent and a liquid crystal display element, and more specifically, a vertical alignment liquid crystal aligning agent excellent in printability and vertical alignment, and a liquid crystal display element obtained from the vertical alignment liquid crystal aligning agent About.

Conventionally, as a liquid crystal display element, a liquid crystal alignment film is formed on the surface of a substrate provided with a transparent conductive film to form a liquid crystal display element substrate. A cell having a sandwich structure is formed by forming an anisotropic nematic liquid crystal layer, and the major axis of the liquid crystal molecule is continuously twisted from 0 to 360 degrees from one substrate to the other substrate. There are known liquid crystal display elements having liquid crystal cells such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, and IPS (In Plane Switching) type. (See Patent Document 1 and Patent Document 2).
In such a liquid crystal cell, the liquid crystal alignment film is usually formed by a method (rubbing method) in which the surface of the organic film formed on the surface of the substrate is rubbed in one direction with a cloth material such as rayon. As such an organic film, those made of a polyimide resin obtained by polycondensation reaction of a diamine compound and a dianhydride are widely used from the viewpoint of heat resistance and electrical characteristics.

By the way, in a liquid crystal cell of TN (Twisted Nematic) type, STN (Super Twisted Nematic) type or the like, the liquid crystal alignment film tilts the liquid crystal molecules at a predetermined angle (usually 3 to 10 °) with respect to the substrate surface. It is necessary to have a pretilt angle characteristic. Here, the “pretilt angle” in this specification represents an angle of inclination of liquid crystal molecules from a direction parallel to the substrate surface.
In addition, as an operation mode of a liquid crystal display element different from the above, a vertical (homeotropic) alignment mode in which liquid crystal molecules having negative dielectric anisotropy are aligned perpendicular to the substrate, that is, at a pretilt angle of about 90 °, is also known. ing. In this operation mode, when a voltage is applied between the substrates, the liquid crystal molecules are inclined from the normal direction of the substrate toward one direction in the substrate surface.
In order to develop a high pretilt angle required in such various modes, it is known that a polyimide resin having a bulky substituent such as an octadecyl group may be used as the liquid crystal alignment film. Among such substituents, those having a bulky and rigid steroid skeleton are particularly useful in order to develop a high pretilt angle. A polyimide resin having such a bulky substituent can be obtained by using a diamine compound or dianhydride having a bulky substituent during the synthesis.
In recent years, with the increase in size of liquid crystal display elements, a liquid crystal alignment film having a large area is required. Therefore, the liquid crystal alignment agent for forming a liquid crystal alignment film has a printability (applicability). There is a further need for improvement.

JP 56-91277 A JP-A-1-120528 JP-A-4-281427 JP 2004-331937 A JP 2006-010896 A

An object of the present invention is to provide a vertical alignment type liquid crystal aligning agent excellent in printability and vertical alignment.
Another object of the present invention is to provide a liquid crystal display device provided with a liquid crystal alignment film obtained from the vertical alignment type liquid crystal alignment agent.

The vertical alignment type liquid crystal aligning agent of this invention is a repeating unit represented by each of following formula (I-1) and following formula (I-2) obtained by reaction of tetracarboxylic dianhydride and a diamine compound. Q ¹ in the following formula (I-1) and Q ² in the following formula (I-2) are used as the following formula (II-1) and the formula (II). -2) a polymer containing a repeating unit having at least one of the divalent organic groups represented by each of the above, and
Containing a mixed solvent,
The mixed solvent is at least one selected from N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide, and N, N-dimethylacetamide. A solvent A consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether, and ethyl-3-ethoxypropionate, and a compound represented by the following formula (III) And at least one kind of solvent C.

(In Formula (I-1), P ¹ is a tetravalent organic group derived from tetracarboxylic acid, and Q ¹ is a divalent organic group derived from a diamine compound. Also, Formula (I-2) P ² is a tetravalent organic group derived from tetracarboxylic acid, and Q ² is a divalent organic group derived from a diamine compound.)

(In the formula (II-1), X ¹ is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S—, a methylene group, 2 carbon atoms. An alkylene group having 6 to 6 carbon atoms or a phenylene group, and R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a fluorine atom having 6 to 20 carbon atoms. In Formula (II-2), X ¹ is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—. , —S—, a methylene group, an alkylene group having 2 to 6 carbon atoms, or a phenylene group, and R ² is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms or a group having 5 to 30 carbon atoms. (It is a divalent organic group having a fluorine atom.)

(In Formula (III), Z is —O—, —CO— or —COO—, R ³ and R ⁴ are each a monovalent hydrocarbon group, and the total number of carbon atoms of R ³ and R ⁴ is Is 6-10.)

In the present invention, the boiling point of the solvent C is preferably 140 ° C. or higher.
Moreover, it is preferable that the solvent C satisfy | fills the conditions in any one of following (1)-(3).
(1) In the formula (III), a compound in which Z is —O— and the total number of carbon atoms of R ³ and R ⁴ is 6 to 10.
(2) A compound in which, in the formula (III), Z is —CO— and the total number of carbon atoms of R ³ and R ⁴ is 8.
(3) In the formula (III), a compound in which Z is —COO— and R ³ and R ⁴ have a total of 6 to 9 carbon atoms.
Moreover, it is preferable that the solvent C satisfy | fills the conditions in any one of following (4)-(6).
(4) In the formula (III), Z is —O—, and the total number of carbon atoms of R ³ and R ⁴ is 6 to 10, and the surface tension is 25 mN / m or less.
(5) A compound in which, in formula (III), Z is —CO— and the total number of carbon atoms of R ³ and R ⁴ is 8, and the surface tension is 24 mN / m or less.
(6) A compound having the surface tension of 26 mN / m or less, wherein Z is —COO— and the total number of carbon atoms of R ³ and R ⁴ is 6 to 9 in the formula (III).
Moreover, it is preferable that the content rate of the solvent C in a mixed solvent is 0.1 to 40 weight%.

  The liquid crystal display element of the present invention comprises a vertical alignment liquid crystal alignment film obtained from the vertical alignment liquid crystal alignment agent.

According to the vertical alignment type liquid crystal aligning agent according to the present invention, it is possible to obtain a liquid crystal alignment film having excellent printability and excellent vertical alignment.
The liquid crystal display element according to the present invention can be effectively used in various devices, and is suitable as a display device for a desktop computer, wristwatch, table clock, mobile phone, counting display board, word processor, personal computer, liquid crystal television, and the like. Can be used.

Hereinafter, the present invention will be described in detail.
The vertical alignment type liquid crystal aligning agent (hereinafter, also referred to as “liquid crystal aligning agent”) according to the present invention is obtained by reacting tetracarboxylic dianhydride with a diamine compound. I-2) contains a polymer composed of a repeating unit and a mixed solvent.
Among the above repeating units, a polymer containing a repeating unit represented by the above formula (I-1) (hereinafter also referred to as “specific polyamic acid polymer”) is usually tetracarboxylic dianhydride and It can be obtained by reacting a diamine compound with an organic solvent. In addition, the polymer containing the repeating unit represented by the above formula (I-2) (hereinafter, also referred to as “specific polyimide polymer”) has a dehydrating ring closure at the amic acid portion of the specific polyamic acid polymer. It is obtained by doing.
Hereinafter, the manufacturing method of the specific polyamic acid polymer which comprises the liquid crystal aligning agent which concerns on this invention, and a specific polyimide polymer is demonstrated.

[Tetracarboxylic dianhydride]
Examples of the tetracarboxylic dianhydride that can be used to obtain the specific polyamic acid polymer and / or the specific polyimide polymer constituting the liquid crystal aligning agent according to the present invention include, for example, butanetetracarboxylic dianhydride 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-diethyl-1,2,3 , 4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic Acid dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobut Tetracarboxylic 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, 1,2,4-tricarboxycyclopentylacetic acid dianhydride, bicyclo [2.2.1] heptane-2,3 , 5,6-tetracarboxylic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic dianhydride, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane-3,4,8,9-tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic 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 anhydride, bicyclo [2,2,2] -oct-4-ene-2,3,5,6 -Tetracarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, represented by the following formulas (1) and (2) Aliphatic and cycloaliphatic tetracarboxylic dianhydrides such as compounds obtained; pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4 4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic 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-furan Tetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4 , 4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3,3 ′, 4,4 ′ -Biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (an 1-butanediol-bis (anhydrotrimellitate), 1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate) Aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (3) to (6): 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) Can be mentioned. These may be used alone or in combination of two or more.

(Wherein R ¹¹ and R ¹² represent a divalent organic group having an aromatic ring, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group, and a plurality of R ⁴ and R ⁵ are the same. But it may be different.)

  Of these, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-diethyl-1, 2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-diethyl-1,2,3,4- Cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane Tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1 , 2,4,5-Cyclohe Santetracarboxylic 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-hexahydride -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, 2,3,5-tricarboxycyclopentyl acetate At least one alicyclic tet selected from anhydrides The lacarboxylic dianhydride is preferably contained in an amount of 50 mol% or more based on the total tetracarboxylic dianhydride, and more preferably 70 mol% or more from the viewpoint of improving the characteristics.

[Diamine compound]
Q ¹ and Q ² in the repeating unit represented by the above formula (I-1) and the above formula (I-2) (hereinafter referred to as “specific repeating unit”) are organic groups derived from a diamine compound. This corresponds to a residue obtained by removing two amino groups from a diamine compound. In the present invention, a polymer containing a repeating unit having at least one of the organic groups represented by the above formula (II-1) and the above formula (II-2) is used as Q ¹ and Q ² .

In the above formula (II-1), R ¹ has an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a fluorine atom having 6 to 20 carbon atoms. It is a monovalent organic group.
Here, examples of the alkyl group having 10 to 20 carbon atoms include an n-decyl group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosyl group.
Examples of the monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms include cycloaliphatic skeletons derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, and cyclodecane; bridged fats such as norbornene and adamantane And monovalent organic groups having a cyclic skeleton; a steroid skeleton such as cholesterol and cholestanol. The monovalent organic group having the alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom.
Examples of the monovalent organic group having a fluorine atom having 6 to 20 carbon atoms include linear alkyl groups having 6 to 20 carbon atoms such as n-hexyl group, n-octyl group and n-decyl group; A part or all of hydrogen atoms in an organic group such as an alicyclic hydrocarbon group having 6 to 20 carbon atoms such as a group or a cyclooctyl group; an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group or a biphenyl group Are substituted with a fluorine atom, a fluoroalkyl group or a fluoroalkyloxy group.

In the formula (II-1), the group represented by X ¹ is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S—, A methylene group, an alkylene group having 2 to 6 carbon atoms, and a phenylene group, and among these, particularly preferred are groups represented by -O-, -CO-, -COO-, and -OCO-.

  Specific examples of the diamine compound having a group represented by the above formula (II-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 (7) to (22).

In the above formula (II-2), R ² is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms or a divalent organic group having a fluorine atom having 5 to 30 carbon atoms.
Here, examples of the divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms include alicyclic skeletons derived from cycloalkanes such as cyclobutane, cyclopentane, cyclohexane, and cyclodecane; and bridges such as norbornene and adamantane. An alicyclic skeleton; a divalent organic group having a steroid skeleton such as cholesterol and cholestanol. The divalent organic group having the alicyclic skeleton may be a group substituted with a halogen atom, preferably a fluorine atom.
Specific examples of the divalent organic group having a fluorine atom having 5 to 30 carbon atoms include linear alkyl groups having 5 to 30 carbon atoms such as n-hexyl group, n-octyl group and n-decyl group. A part of hydrogen atoms in an organic group such as an alicyclic hydrocarbon group having 5 to 30 carbon atoms such as a cyclohexyl group or a cyclooctyl group; an aromatic hydrocarbon group having 5 to 30 carbon atoms such as a phenyl group or a biphenyl group; Or the group which substituted all with the fluorine atom or the fluoroalkyl group is mentioned. Specific examples of the diamine compound having a group represented by the above formula (II-2) include compounds represented by the following formulas (23) to (27).

  In the specific polyamic acid polymer and / or the specific polyimide polymer used in the present invention, the ratio of the specific repeating unit is preferably 7 mol% or more in all repeating units from the viewpoint of vertical alignment, More preferably, it is 10 mol% or more.

In the synthesis of the specific polyamic acid polymer and / or the specific polyimide polymer used in the present invention, Q ¹ and Q ² are represented by the above formula (II-1) or the above as long as the effects of the present invention are not impaired. A repeating unit having a group other than the divalent organic group represented by the formula (II-2) (hereinafter referred to as “other repeating unit”) may be contained.

Examples of the diamine compound for obtaining other repeating units include p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2,5-dimethyl-1, and the like. 4-phenylenediamine, 2,5-diethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4 , 4'-diaminodiphenylethane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-di (trifluoro Methyl) -4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4 ' Diaminobiphenyl, 3,3′-di (trifluoromethyl) -4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 4,4 '-Diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 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, 3,4′-diaminobenzophenone, 4,4 '-Diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) pheny [Ru] hexafluoropropane, 2,2-bis (4-aminophenyl) propane, 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-amino) Phenyl) -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, '-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-2-trifluoromethyl) Aromatic diamines such as phenoxy] -octafluorobiphenyl, 4- (4-n-heptylcyclohexyl) phenoxy-2,4-diaminobenzene;
1,3-bis (aminomethyl) benzene, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine Aliphatic diamines such as

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 Two primary amino groups in the molecule, such as phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, bis (4-aminophenyl) phenylamine, and nitrogen atoms other than the primary amino group A diamine having:
Examples thereof include compounds represented by the following formulas (28) to (30).
These diamine compounds can be used alone or in combination of two or more.

(Wherein R ⁶ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ⁶ may be the same or different, p is an integer of 1 to 3, and q is 1 to 20) And y is an integer of 2 to 12, and z is an integer of 1 to 5.)

  Among these, p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 2-ethyl-1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,5-diethyl- 1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 4,4′-diaminodiphenylmethane, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2, 2′-di (trifluoromethyl) -4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3, 3′-diethyl-4,4′-diaminobiphenyl, 3,3′-di (trifluoromethyl) -4,4′-diaminobiphenyl, 4,4′-diaminodiphenyl ester Ter, 4,4'-diaminobenzophenone, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,6-diaminopyridine, 3,4-diamino Pyridine and the like can be mentioned as preferred examples.

[Synthesis of specific polyamic acid polymer]
The ratio of the tetracarboxylic dianhydride and the diamine compound used for the synthesis reaction of the specific polyamic acid polymer is such that the acid anhydride group of the tetracarboxylic dianhydride is equivalent to 1 equivalent of the amino group of the diamine compound. Is preferably a ratio of 0.2 to 2.0 equivalents, more preferably 0.8 to 1.2 equivalents.
The synthesis reaction of the specific polyamic acid polymer is usually performed in an organic solvent under a temperature condition of -20 ° C to 150 ° C, preferably 0 to 100 ° C.

Here, the organic solvent is not particularly limited as long as it can dissolve a specific polyamic acid polymer to be synthesized, and specific examples thereof include 1-methyl-2-pyrrolidone, N, N- Aprotic polar solvents such as dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide; phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol And so on.
The amount of organic solvent used (α) is usually such that the total amount (β) of tetracarboxylic dianhydride and diamine compound is 0.1 to 30% by weight with respect to the total amount (α + β) of the reaction solution. It is preferable that

  In addition, the organic solvent includes a specific polyamic acid polymer that generates an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, a hydrocarbon, or the like, which is a poor solvent for the specific polyamic acid polymer. It can be used in combination as long as the coalescence does not precipitate. Specific examples of such poor solvents include 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, malonic 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, Examples thereof include 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene and the like.

  As described above, a reaction solution obtained by dissolving a specific polyamic acid polymer 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 thereby generate a specific polymer polyamic acid. Can be obtained. Also, the specific polyamic acid polymer is purified again by dissolving the specific polyamic acid polymer again in an organic solvent and then precipitating with a poor solvent or depressurizingly distilling with an evaporator once or several times. be able to.

[Synthesis of specific polyimide polymer]
The specific polyimide polymer constituting the liquid crystal aligning agent of the present invention can be synthesized by dehydrating and ring-closing a specific polyamic acid polymer. The specific polyimide polymer used in the present invention may be partially dehydrated and ring-closed with an imidation rate of less than 100%. The “imidation ratio” herein is a value expressed as a percentage of the ratio of repeating units having an imide ring or an isoimide ring in all repeating units of polyimide. The imidation ratio of the specific polyamic acid polymer and / or specific polyimide polymer used in the present invention is preferably 40% or more. Dehydration and ring closure of a specific polyamic acid polymer may be performed by (i) a method of heating the specific polyamic acid polymer or (ii) dissolving the specific polyamic acid polymer in an organic solvent. A method of condensing and synthesizing by a method of adding a dehydration ring closure catalyst and heating as necessary is used.
The reaction temperature in the method of heating the specific polyamic acid polymer (i) above 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 resulting polyimide may decrease.
On the other hand, in the method of adding a dehydrating agent and a dehydrating ring closure catalyst to the solution of the specific polyamic acid polymer (ii) above, examples of the dehydrating agent include acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. Can be used. Although the usage-amount of a dehydrating agent is based on the desired imidation rate, it is preferable to set it as 0.01-20 mol with respect to 1 mol of repeating units of a specific polyamic acid polymer. 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-closing catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. The imidation rate can be increased as the amount of the dehydrating agent and the dehydrating ring-closing catalyst is increased. In addition, as an organic solvent used for dehydration ring closure reaction, the same organic solvent illustrated as what is used for the synthesis | combination of a specific polyamic acid polymer 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, a specific polyimide polymer can be refine | purified by performing operation similar to the purification method of a specific polyamic acid polymer with respect to the reaction solution obtained in this way.

[End-modified polymer]
The specific polyamic acid polymer and specific polyimide polymer used in 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 polymer can be synthesized by adding an acid monoanhydride, a monoamine compound, a monoisocyanate compound or the like to the reaction system when a specific polyamic acid polymer is synthesized. 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 liquid crystal aligning agent according to the present invention preferably has a viscosity of 20 to 800 mPa · s, and has a viscosity of 30 to 500 mPa · s, when a 10% by weight solution is obtained. It is more preferable that
Here, the solution viscosity (mPa · s) of the polymer refers to a solution measured at 25 ° C. using an E-type viscometer for a solution diluted to a solid content concentration of 10% by weight using a predetermined solvent.

[Imidation rate of polymer]
The specific polyimide polymer obtained as described above preferably has an imidation ratio of 40% or more from the viewpoint of improving voltage holding characteristics.
The value of the imidization ratio of the specific polyimide polymer used in the present invention is determined by performing ¹ H-NMR at room temperature using tetramethylsilane as a reference substance after polyimide is dried at room temperature under reduced pressure and then dissolved in deuterated dimethyl sulfoxide. It is measured and obtained by the formula shown by the following formula (i).
Formula (i) Imidation ratio (%) = (1-A ¹ / A ² × α) × 100
Here, A ¹ is a peak area derived from protons of NH group (10 ppm), A ² is a peak area derived from protons derived from an aromatic ring (7 to 8 ppm), and α is a precursor of a polymer (a specific polyamic acid polymer) ) Is the number ratio of protons derived from the aromatic ring to one proton of the NH group.

[Vertical alignment type liquid crystal alignment agent]
The liquid crystal aligning agent of the present invention is constituted by dissolving the above-mentioned specific polyamic acid polymer and / or specific polyimide polymer in a mixed solvent. Here, the temperature when preparing the liquid crystal aligning agent is preferably 0 ° C to 200 ° C, more preferably 20 ° C to 60 ° C.
The mixed solvent used in the liquid crystal aligning agent of the present invention is N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide, and N, N-dimethyl. A solvent A consisting of at least one selected from acetamide, a solvent B consisting of at least one selected from butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether, and ethyl-3-ethoxypropionate; III) and a solvent C composed of at least one selected from the compounds represented by (3).

As the solvent C, those having a boiling point of 140 to 190 ° C. are preferable from the viewpoint of uniformizing the liquid drying rate.
Further, as the solvent C, those satisfying any of the following conditions (1) to (3) are preferable from the viewpoint of liquid spreading property of the obtained liquid crystal aligning agent.
(1) A solvent comprising a compound of the above formula (III) wherein Z is —O— and the total number of carbon atoms of R ³ and R ⁴ is 6 to 10, particularly preferably a surface tension of 25 mN / m. The following:
(2) In the above formula (III), Z is —CO—, and a solvent comprising a compound in which the total number of carbon atoms of R ³ and R ⁴ is 8, particularly preferably a surface tension of 24 mN / m or less. thing. (3) In the above formula (III), Z is —COO— and a solvent comprising a compound in which the total number of carbon atoms of R ³ and R ⁴ is 6 to 9, particularly preferably a surface tension of 26 mN / m or less Things.
Specific examples of the solvent (1) include di-n-pentyl ether and di-n-butyl ether.
Specific examples of the solvent (2) include 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone, 5-methyl-2-octanone, 2-methyl-4-octanone, 2,4-dimethyl- Examples include 3-heptanone and 1-cyclohexyl-1-propanone.
Specific examples of the solvent (3) include acetic acid-n-hexyl, acetic acid-2-ethylbutyl, propionic acid-n-butyl, acetic acid-n-pentyl, acetic acid-n-butyl and the like.

The content ratio of the solvent A in the mixed solvent is preferably 40 to 80% by weight, more preferably 45 to 70% by weight.
The content ratio of the solvent B in the mixed solvent is preferably 10 to 50% by weight, and more preferably 20 to 50% by weight.
The content ratio of the solvent C in the mixed solvent is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight.
The mixed solvent preferably has a composition in which the polymer does not precipitate in the obtained liquid crystal aligning agent and the surface tension of the liquid crystal aligning agent is in the range of 25 to 40 mN / m.

The mixed solvent may contain a solvent other than the solvent A, the solvent b, and the solvent C (hereinafter referred to as “other solvent”) as long as the effects of the present invention are not impaired.
Specific examples of such other solvents include γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, methyl methoxypropionate, ethylene glycol dimethyl ether, ethylene glycol diethyl Ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate And so on.

  The solid 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 resin film that becomes a liquid crystal aligning film. When the solid content concentration is less than 1% by weight, the film thickness of the resin film is If the solid content concentration exceeds 10% by weight, the resin film becomes too thick to obtain a good liquid crystal alignment film. 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 4 to 10% by weight, and thereby the solution viscosity is in the range of 10 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 2 to 5% by weight, and thereby the solution viscosity is in the range of 5 to 15 mPa · s.

  The liquid crystal aligning agent according to the present invention can contain an epoxy compound, and specific examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and tripropylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetra Glycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-p-phenylenediamine, N, N, N ′, N′-tetraglycidyl-m-phenylenedia N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenyl ether, N, N, N ′ , N′-tetraglycidyl-2,2′-dimethyl-4,4′-diaminobiphenyl, N, N, N ′, N′-tetraglycidyl-1,2-diaminocyclohexane, N, N, N ′, N '-Tetraglycidyl-1,3-diaminocyclohexane, N, N, N', N'-tetraglycidyl-1,4-diaminocyclohexane, bis (N, N-diglycidyl-4-aminocyclohexyl) methane, bis (N , N-diglycidyl-2-methyl-4-aminocyclohexyl) methane, bis (N, N-diglycidyl-3-methyl-4-aminocyclohexyl) methane, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,4-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N-diglycidylaminomethyl) benzene, 1 , 4-Bis (N, N-diglycidylaminomethyl) benzene, 1,3,5-tris (N, N-diglycidylaminomethyl) cyclohexane, 1,3,5-tris (N, N-diglycidylamino) And methyl) benzene and compounds represented by the following formulas (31) to (35).

  In addition, the liquid crystal aligning agent of the present invention may contain a functional silane-containing compound from the viewpoint of improving the adhesion to the substrate surface within a range that does not impair the intended physical properties. 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- Aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl 1,4,7-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- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, 3- ( N, N-diglycidyl) aminopropyltrimethoxysilane It can be mentioned.

[Production of display element using liquid crystal aligning agent]
The liquid crystal display element using the vertical alignment type 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 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, a glass such as float glass or soda glass; a transparent substrate made of a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, or polycarbonate can be used. As the 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. In applying the liquid crystal aligning agent, for example, a functional silane-containing compound or a functional titanium-containing compound can be applied in advance in order to further improve the adhesion between the substrate surface and the resin film. The heating temperature after application of the liquid crystal aligning agent is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The liquid crystal aligning agent of the present invention forms a resin film that becomes an alignment film by removing the organic solvent after coating. However, when imidization has not progressed completely, dehydration ring closure proceeds by further heating. It is also possible to obtain a more imidized resin film. The film thickness of the formed resin film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

(2) Two substrates on which the vertical liquid crystal alignment film is formed as described above are manufactured, the two substrates are arranged to face each other with a gap (cell gap) therebetween, and the peripheral portions of the two substrates are sealed. A liquid crystal cell is formed by laminating using an agent, injecting and filling liquid crystal into the cell gap defined by the substrate surface and the sealing agent, and sealing the injection hole. 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 transparent substrate side 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.

Further, various measurements in Examples and Comparative Examples were performed by the following methods.
(1) Vertical alignment evaluation:
When the vertical alignment type liquid crystal display device produced by the above method was observed visually from the vertical direction with respect to the liquid crystal display device when no voltage was applied under crossed Nicols, it was judged as “good” when no light leakage was observed.
(2) Voltage holding ratio At 60 ° C., a voltage of 5 V was applied to the liquid crystal display element with an application time of 60 microseconds and a span of 16.7 microseconds, and after 16.7 milliseconds after the application was released. The voltage holding ratio was measured.
(3) Printability evaluation:
A solution was prepared such that the viscosity was 15 to 25 mPa · sec (solid content concentration 6.0 wt% to 8.0 wt%) and the solvent composition was the composition shown in Tables 2 and 3 below, and a liquid crystal aligning agent printer ( Using Nissha Printing Co., Ltd., an ITO film having a thickness of 200 nm and a width of 20 μm was applied to the transparent electrode surface of the glass substrate with a transparent electrode formed in stripes at intervals of 100 μm. The coated substrate is allowed to stand for 1 minute, and after the liquid crystal alignment film is formed by firing, the periphery and the center of the liquid crystal alignment film are observed with a microscope with a magnification of 10 times. "A case where there was coating unevenness or repellency was judged as" bad ".
(4) Imidization rate of imidized polymer The imidized polymer was dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. It calculated | required by the formula shown by Formula (i).
Formula (i) Imidation ratio (%) = (1-A ¹ / A ² × α) × 100
A ¹ : Peak area derived from NH group protons (10 ppm)
A ² : Peak area derived from protons derived from aromatic rings (7 to 8 ppm)
α: Number ratio of protons derived from an aromatic ring to one proton of NH group in the precursor of the polymer (polyamic acid) (5) Solution viscosity of the polymer The solution viscosity (mPa · s) of the polymer is a predetermined value. A solution diluted with a solvent to a solid content concentration of 10% by weight was measured at 25 ° C. using an E-type rotational viscometer.

<Synthesis Examples 16-21>
To the N-methyl-2-pyrrolidone, a diamine compound and a tetracarboxylic dianhydride (indicated in the table as “acid anhydride”) were added in this order with the composition shown in Table 1 to obtain a solid content concentration of 20% by weight. A solution was prepared and reacted at 60 ° C. for 4 hours to obtain polyamic acid polymer solutions (PA-1) to (PA-6). A small amount of each of these polyamic acid polymer solutions was taken, diluted with N-methyl-2-pyrrolidone to a solid content concentration of 10% by weight, and the solution viscosity was measured. The results are shown in Table 1.

<Synthesis Examples 1-15>
To the N-methyl-2-pyrrolidone, a diamine compound and a tetracarboxylic dianhydride (indicated in the table as “acid anhydride”) were added in this order with the composition shown in Table 1 to obtain a solid content concentration of 20% by weight. A solution was prepared and reacted at 60 ° C. for 4 hours to obtain a polyamic acid polymer solution. After diluting the obtained polyamic acid polymer solution twice with N-methyl-2-pyrrolidone, and adding pyridine and acetic anhydride in the number of moles shown in Table 1 to the repeating units of the polyacic acid polymer. The mixture was heated to 110 ° C. and dehydrated and closed for 4 hours. After the imidization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (by this operation, pyridine and acetic anhydride used in the imidization reaction were removed from the system), and the solid concentration was about 20% by weight of polyimide polymer solutions (PI-1) to (PI-15) were obtained. Table 1 shows the viscosity of the N-methyl-2-pyrrolidone solution (10% by weight) of these polyimide polymers and the imidization ratio.

In the diamine compounds and acid anhydrides in Table 1, the numbers in parentheses indicate the content ratio, and the meanings of the symbols in Table 1 are as follows.
<Diamine compound>
D-1: Diamine compound represented by the above formula (10) D-2: Diamine compound represented by the above formula (11) D-3: Diamine compound represented by the above formula (13) D-4: Above Diamine compound D-5 represented by formula (21): p-phenylenediamine D-6: 4,4′-diaminodiphenylmethane D-7: 4,4′-diaminodiphenyl ether D-8: 2,2′-dimethyl -4,4'-diaminobiphenyl <tetracarboxylic dianhydride>
T-1: 1,2,4,5-cyclohexanetetracarboxylic dianhydride T-2: 2,3,5-tricarboxycyclopentylacetic acid dianhydride T-3: 1,2,3,4-cyclobutanetetra Carboxylic dianhydride T-4: 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -Furan-1,3-dione T-5: pyromellitic dianhydride

<Example 1>
The polymer solution (PI-1) obtained in Synthesis Example 1 was dissolved in a mixed solvent of N-methyl-2-pyrrolidone / butyl cellosolve / acetic acid-n-hexyl, and the solvent composition was N-methyl-2 by weight ratio. -Pyrrolidone / butyl cellosolve / acetic acid-n-hexyl = 50/40/10 A solid content concentration of 6% by weight was prepared. Subsequently, it filtered using the filter with a hole diameter of 0.2 micrometer, and obtained the liquid crystal aligning agent which concerns on this invention. When this liquid crystal aligning agent was evaluated for printability, no repelling or coating unevenness was observed in the coating film, and it was confirmed that the liquid crystal aligning agent had good printability.
Subsequently, the liquid crystal aligning agent which concerns on this invention was prepared like the above except having made solid content concentration into 4 weight%.
The obtained liquid crystal aligning agent was applied onto a transparent conductive film made of an ITO film provided on one surface of a glass substrate having a thickness of 1 mm by a spinner and dried at 200 ° C. for 60 minutes. A film of 08 μm was formed.
In this way, two substrates for liquid crystal display elements are prepared, and aluminum oxide spheres having a diameter of 3.5 μm are contained in the outer edge portion of the surface on which the liquid crystal alignment film is formed in each of these liquid crystal display element substrates. After applying the epoxy resin adhesive, the liquid crystal alignment films were overlapped and pressed through a gap so as to face each other, and the adhesive was cured in this state.
Next, a negative type liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) is filled in the cell gap between the liquid crystal display element substrates through a liquid crystal injection port provided in advance, and then the injection port is sealed with an acrylic photo-curing adhesive And the liquid crystal display element was produced by sticking a polarizing plate on both surfaces of the outer side of the board | substrate for liquid crystal display elements.
When the vertical alignment evaluation was performed on the obtained liquid crystal display element, it was good. Moreover, when the voltage holding ratio was measured, it was 99% or more, and it was confirmed that it was extremely good.

<Examples 2-28 and Comparative Examples 1-3>
According to the formulation shown in the following Table 2 and Table 3, a solution having a solid content concentration of 6% was prepared in the same manner as in Example 1 to obtain a liquid crystal aligning agent, and the printability of the liquid crystal aligning agent was evaluated. Similarly, a solution having a solid content concentration of 4% was prepared to produce a liquid crystal display element. Then, vertical alignment evaluation and voltage holding ratio were measured. The results are shown in Tables 2 and 3.

In the polymers of Examples 21 to 28 in Table 2, the mixing ratio of the two polymers is 50/50 (% by weight).
The solvents shown in Tables 2 and 3 are as follows.
<Solvent>
A-1: γ-butyrolactone A-2: N-methyl-2-pyrrolidone A-3: 1,3-dimethyl-2-imidazolidinone B-1: butyl cellosolve B-2: diacetone alcohol B-3: propylene Carbonate B-4: Diethylene glycol diethyl ether C-1: Acetic acid-n-hexyl C-2: Acetic acid-n-pentyl C-3: 5-nonanone C-4: 5-methyl-2-octanone C-5: 2, 4-Dimethyl-3-heptanone

  As is clear from the above results, it was confirmed that the liquid crystal aligning agent according to the present invention has excellent printability, is excellent in vertical alignment, and forms a liquid crystal alignment film having a high voltage holding ratio.

Claims (6)

At least one repeating unit selected from the group consisting of repeating units represented by the following formula (I-1) and the following formula (I-2), which is obtained by a reaction between a tetracarboxylic dianhydride and a diamine compound. Are represented by the following formulas (II-1) and (II-2), respectively, as Q ¹ in the following formula (I-1) and Q ² in the following formula (I-2). A polymer containing a repeating unit having at least one of the organic groups, and
Containing a mixed solvent,
The mixed solvent is at least one selected from N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide, and N, N-dimethylacetamide. A solvent A consisting of butyl cellosolve, diacetone alcohol, propylene carbonate, diethylene glycol diethyl ether, and ethyl-3-ethoxypropionate, and a compound represented by the following formula (III) And a vertical alignment liquid crystal aligning agent comprising at least one solvent C.

(In Formula (I-1), P ¹ is a tetravalent organic group derived from tetracarboxylic acid, and Q ¹ is a divalent organic group derived from a diamine compound. Also, Formula (I-2) P ² is a tetravalent organic group derived from tetracarboxylic acid, and Q ² is a divalent organic group derived from a diamine compound.)

(In the formula (II-1), X ¹ is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—, —S—, a methylene group, 2 carbon atoms. An alkylene group having 6 to 6 carbon atoms or a phenylene group, and R ¹ is an alkyl group having 10 to 20 carbon atoms, a monovalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms, or a fluorine atom having 6 to 20 carbon atoms. In Formula (II-2), X ¹ is a single bond, —O—, —CO—, —COO—, —OCO—, —NHCO—, —CONH—. , —S—, a methylene group, an alkylene group having 2 to 6 carbon atoms, or a phenylene group, and R ² is a divalent organic group having an alicyclic skeleton having 4 to 40 carbon atoms or a group having 5 to 30 carbon atoms. (It is a divalent organic group having a fluorine atom.)

(In Formula (III), Z is —O—, —CO— or —COO—, R ³ and R ⁴ are each a monovalent hydrocarbon group, and the total number of carbon atoms of R ³ and R ⁴ is Is 6-10.)   The vertical alignment type liquid crystal aligning agent according to claim 1, wherein the boiling point of the solvent C is 140 ° C. or more. The vertical alignment liquid crystal aligning agent according to claim 1 or 2, wherein the solvent C satisfies one of the following conditions (1) to (3).
(1) In the formula (III), a compound in which Z is —O— and the total number of carbon atoms of R ³ and R ⁴ is 6 to 10.
(2) A compound in which, in the formula (III), Z is —CO— and the total number of carbon atoms of R ³ and R ⁴ is 8.
(3) In the formula (III), a compound in which Z is —COO— and R ³ and R ⁴ have a total of 6 to 9 carbon atoms. The vertical alignment type liquid crystal aligning agent according to any one of claims 1 to 3, wherein the solvent C satisfies any of the following conditions (4) to (6).
(4) In the formula (III), Z is —O—, and the total number of carbon atoms of R ³ and R ⁴ is 6 to 10, and the surface tension is 25 mN / m or less.
(5) A compound in which, in formula (III), Z is —CO— and the total number of carbon atoms of R ³ and R ⁴ is 8, and the surface tension is 24 mN / m or less.
(6) A compound having the surface tension of 26 mN / m or less, wherein Z is —COO— and the total number of carbon atoms of R ³ and R ⁴ is 6 to 9 in the formula (III).   The vertical alignment type liquid crystal aligning agent according to any one of claims 1 to 4, wherein a content ratio of the solvent C in the mixed solvent is 0.1 to 40% by weight.   A liquid crystal display element comprising a vertical alignment type liquid crystal alignment film obtained from the vertical alignment type liquid crystal alignment agent according to claim 1.