KR20120042612A - Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display device, and polymers contained therein - Google Patents

Abstract

PURPOSE: A liquid crystal alignment agent is provided to a liquid crystal alignment film with excellent voltage preservative rate, and capable of obtaining excellent liquid crystal aligning properties. CONSTITUTION: A liquid crystal alignment agent comprises polyamic acid, which is obtained by reaction of tetracarboxylic dianhydride and diamine, and/or imidized polymer thereof. The tetracarboxylic dianhydride comprises aliphatic tetracarboxylic dianhydride and/or alicyclic tetracarboxylic dianhydride, and the diamine comprises a compound in chemical formula D-1. In chemical formula D-1, one of R^1-R^5 and one of R^6-R^10 are primary amino group, and residue of R^1-R^10 is respectively and independently hydrogen, fluorine, or a C1-6 alkyl group, an alkoxy group, or a fluoroalkyl group.

Description

Liquid crystal aligning agent, liquid crystal aligning film, liquid crystal display element, and polymer contained therein {LIQUID CRYSTAL ALIGNING AGENT, LIQUID CRYSTAL ALIGNMENT FILM, LIQUID CRYSTAL DISPLAY DEVICE, AND POLYMERS CONTAINED THEREIN}

This invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element, Specifically, the liquid crystal aligning agent and liquid crystal aligning film which can be suitably applied to a horizontal alignment type liquid crystal display element (horizontal alignment mode), and this liquid crystal aligning film It relates to a liquid crystal display element provided.

As one of the conventional liquid crystal display elements, horizontally oriented liquid crystal display elements known as twisted nematic display mode (TN mode), transverse electric field display mode (IPS mode), and fringe field switching mode (FFS mode) are known. In this liquid crystal display element, liquid crystal molecules are enclosed between a pair of opposing substrates, the liquid crystal molecules are oriented parallel to the substrate surface (horizontal alignment), and a voltage is applied thereto to change the direction of the liquid crystal molecules. Thereby, the light switching function by a liquid crystal molecule is expressed in a liquid crystal display element.

In a liquid crystal display element, the orientation control of liquid crystal molecules is performed by a liquid crystal aligning film. Generally, a liquid crystal aligning film can be obtained by apply | coating the liquid crystal aligning agent containing polyimide or polyamic acid to a board | substrate, baking this, and performing what is called a rubbing process which rubs the thin film surface after baking in a fixed direction with cloth.

In order to improve the display performance of a liquid crystal display element, it is necessary to orientate liquid crystal molecules in a specific direction at the time of no voltage application, and in order to achieve this, various liquid crystal aligning agents are proposed (for example, refer patent documents 1-3). . Patent Literature 1 discloses a liquid crystal alignment method using a polyimide obtained by a polymerization reaction of pyromellitic dianhydride (PMDA) with diamine. The aromatic polyimide produced using PMDA is said to have a good liquid crystal orientation in terms of high uniaxial orientation due to the rubbing treatment and induction of interaction between the benzene rings of the liquid crystal molecules.

In addition, Patent Literatures 2 and 3 disclose liquid crystal aligning agents containing a polyimide obtained by polymerization of an acid dianhydride having a cycloaliphatic structure such as cyclobutanetetracarboxylic anhydride (CB) and diamine and the like. In this alicyclic polyimide etc., compared with the aromatic polyimide like patent document 1, since (1) there is no absorption of a visible light region, the light transmittance of a liquid crystal aligning film is high, (2) rubbing tolerance is favorable, (3) solution There are advantages such as the ease of adjusting the viscosity in the state.

Japanese Laid-Open Patent Publication No. 57-128318 Japanese Patent 4052308 Japanese Laid-Open Patent Publication No. 2010-156934

By the way, in the liquid crystal aligning film formed by alicyclic polyimide etc., although it has the advantage of said (1)-(3) compared with aromatic polyimide, when the liquid crystal molecule is inject | poured between board | substrates, the flow direction at the time of injection is carried out. Flow orientation that is oriented with is likely to occur. Therefore, there exists a possibility that liquid crystal aligning ability may fall due to flow orientation. Moreover, when forming a liquid crystal aligning film by alicyclic polyimide etc., although crosslinking agents, such as an epoxy compound, may be added for the purpose of the improvement of mechanical strength, etc., uniaxial stretchability of a polymer falls by addition of a crosslinking agent. In this case, it is considered that flow orientation tends to occur.

Moreover, in a liquid crystal display element, high voltage retention is calculated | required in order to make display quality favorable, and when designing a liquid crystal aligning film, it is also necessary to examine the voltage integrity characteristic of a liquid crystal display element. By the way, when the present inventors examined, when PMDA was used as an acid dianhydride like the said patent document 1, it was confirmed that liquid crystal orientation is favorable, but the voltage retention of a liquid crystal falls.

This invention is made | formed in view of the said subject, The liquid crystal aligning agent for obtaining the liquid crystal display element which has the outstanding liquid crystal aligning property and voltage preservation characteristic, the liquid crystal aligning film formed with this liquid crystal aligning agent, and the liquid crystal display element provided with the said liquid crystal aligning film. The main purpose is to provide.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the subject of the said prior art, the present inventors reacted the diamine of a specific structure with at least any of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and responded to this reaction. By containing at least any of the polyamic acid obtained by this and the imidation polymer as a polymer component of a liquid crystal aligning agent, it discovered that the said subject can be solved and came to complete this invention. Specifically, the following liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element are provided by this invention.

The present invention provides a liquid crystal aligning agent containing at least any one of polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine and an imidized polymer, wherein the tetracarboxylic dianhydride is aliphatic tetracarboxylic dianhydride and alicyclic tetra. It contains at least any one of carboxylic acid dianhydride, The said diamine contains the compound represented by following formula (D-1), It is characterized by the above-mentioned.

(Wherein R ¹ ? R ¹⁰ is R ¹ ? R ⁵ 1 of R ⁶ and R ¹⁰ One of them is a primary amino group, and the remaining ones are each independently a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 6 carbon atoms, an alkoxy group or a fluoroalkyl group.

According to the liquid crystal aligning agent of this invention, even if it contains an aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride as tetracarboxylic dianhydride, the liquid crystal aligning film which can suppress the flow orientation of a liquid crystal molecule can be formed. . Moreover, when the liquid crystal aligning film formed with the liquid crystal aligning agent of this invention is used for a liquid crystal display element, high voltage retention is shown. Therefore, according to the liquid crystal aligning agent of this invention, the liquid crystal display element which equips the liquid crystal aligning property and voltage preservation characteristic with good balance can be obtained.

Moreover, in this invention, you may use as a tetracarboxylic dianhydride, the mixture of at least any of the said aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. In this case, compared with using an electron independently, liquid-crystal orientation can be improved.

Moreover, according to this invention, the liquid crystal aligning film formed from the liquid crystal aligning agent described above, and the liquid crystal display element provided with this liquid crystal aligning film are provided. Furthermore, the polyamic acid obtained by reaction with the diamine represented by said Formula (D-1) and at least any of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and its imidation polymer (polyimide) are provided. do.

The liquid crystal aligning agent of this invention contains at least any of the polyamic acid obtained by making tetracarboxylic dianhydride and diamine react, and its imidation polymer. Hereinafter, the liquid crystal aligning agent of this invention is demonstrated in detail.

<Polyamic acid>

The polyamic acid contained in the liquid crystal aligning agent of this invention can be obtained by making tetracarboxylic dianhydride and the diamine represented by said formula (D-1) react.

[Tetracarboxylic dianhydride]

As tetracarboxylic dianhydride for synthesizing polyamic acid in the present invention, tetracarboxylic dianhydride (hereinafter also referred to as aliphatic tetracarboxylic dianhydride) having an aliphatic water tank and tetracarboxylic dianhydride having an alicyclic structure (Hereinafter also referred to as alicyclic tetracarboxylic dianhydride).

Herein, "aliphatic tetracarboxylic dianhydride" refers to an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a saturated hydrocarbon group. However, aliphatic tetracarboxylic dianhydride does not need to be comprised only by the linear structure, and may have a structure of cyclic hydrocarbon or an aromatic ring structure in part. In addition, "alicyclic tetracarboxylic dianhydride" refers to an acid dianhydride obtained by dehydration in a molecule of at least two carboxyl groups bonded to an aliphatic ring. However, the alicyclic tetracarboxylic dianhydride does not need to be comprised only with an alicyclic structure or a chain structure, and may have an aromatic ring structure in a part of it.

Specifically, as an aliphatic tetracarboxylic dianhydride, a 1,2,3,4- butane tetracarboxylic dianhydride is mentioned, for example. As the alicyclic tetracarboxylic dianhydride, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic 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'-dione), 5- (2,5-dioxotetrahydro -3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-2 Anhydride, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5, 8,10- tetraone, cyclohexane tetracarboxylic dianhydride, etc. are mentioned. In addition, the thing of that excepting the above can be used for the aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride of Unexamined-Japanese-Patent No. 2010-97188.

As the aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention, among these, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3 , 5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl)- Naphtho [1,2-c] furan-1,3-dione, bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, and And at least one selected from the group consisting of 1,2,3,4-butanetetracarboxylic acid dianhydride is preferred. Moreover, from a viewpoint which can raise a voltage holding ratio more, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, (1S, 2S, 4R, 5R) -cyclohexane tetracarboxylic dianhydride, (1R, 2S) At least one selected from the group consisting of, 4S, 5R) -cyclohexanetetracarboxylic acid dianhydride and 2,3,5-tricarboxycyclopentyl acetic dianhydride is more preferable, even when an epoxy compound as a crosslinking agent is added. From the viewpoint of showing good liquid crystal alignment, 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 and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- At least one selected from the group consisting of (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione is preferred. Among these, Especially preferably, they are 1,2,3,4-cyclobutane tetracarboxylic dianhydride.

In addition, said aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

As tetracarboxylic dianhydride, you may use at least any of said aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, but at least any of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, And tetracarboxylic dianhydride (aromatic tetracarboxylic dianhydride) having an aromatic structure. The term "aromatic tetracarboxylic dianhydride" refers to an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to the same or different aromatic rings.

Specific examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, and 3,3', 4,4'-benzophenone. Tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, and the aromatic tetracarboxylic dianhydride of Unexamined-Japanese-Patent No. 2010-97188 can be used. Preferably it is PMDA. Since PMDA is excellent in liquid-crystal orientation, by combining at least any of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride with PMDA, the orientation in a liquid crystal aligning film can be improved compared with the case where an electron is used alone. It is preferable at the point which can be used. On the other hand, when aliphatic tetracarboxylic acid or alicyclic tetracarboxylic dianhydride is used alone, it is preferable at the point that voltage retention can be improved compared with the mixed system with aromatic tetracarboxylic dianhydride.

When tetracarboxylic acid dianhydride is used by mixing aliphatic or alicyclic and aromatic ones, the proportion of aliphatic or alicyclic tetracarboxylic dianhydride is 10 in total with respect to the total amount of tetracarboxylic dianhydride. 95 mol% is preferable, 30-90 mol% is more preferable, 50-85 mol% is further more preferable, 60-80 mol% is especially preferable. In this case, as for the ratio of aromatic tetracarboxylic dianhydride in a mixed system, 5-90 mol% is preferable with respect to the total amount of tetracarboxylic dianhydride, 10-70 mol% is more preferable, 15-50 Mol% is more preferable, and 20-40 mol% is especially preferable. By setting it as said range, respectively, when it sets as a liquid crystal aligning film, both a high voltage hold ratio and the outstanding liquid crystal alignability can be expressed in a balanced manner. Moreover, rubbing tolerance also becomes favorable.

[Diamine]

At least one part of the diamine used for synthesizing the polyamic acid in the present invention is a compound represented by the formula (D-1). In the formula (D-1), one of R ^{1 to} R ⁵ and R ^{6 to} R ¹⁰ One of them is a primary amino group. That is, the compound represented by said formula (D-1) is the diamine which each one primary amino group couple | bonded with the other benzene ring.

In R <^1> -R <^10> , remainder other than a primary amino group is a hydrogen atom, a fluorine atom, or a C1-C6 alkyl group, an alkoxy group, or a fluoroalkyl group, and may be same or different, respectively. The alkyl group having 1 to 6 carbon atoms may be linear or branched, and specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group , n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group and the like.

As a C1-C6 fluoroalkyl group, what substituted the fluorine atom at least 1 hydrogen atom of the group mentioned as said C1-C6 alkyl group is mentioned. Examples of the alkoxy group having 1 to 6 carbon atoms include those in which the group represented by the above alkyl group having 1 to 6 carbon atoms is bonded to an oxygen atom, and specific examples thereof include a methoxy group and an ethoxy group.

It is preferable that each primary amino group in Formula (D-1) is couple | bonded with the 4-position with respect to -COO-. In addition, R ¹ ? R ¹⁰ Among the remaining ones other than the primary amino group, it is preferable that all of them are hydrogen atoms or at least one of adjacent to the primary amino group is other than a hydrogen atom, and others are hydrogen atoms. In the former case, the planarity of a polyamic acid and its imidation polymer can be improved, and liquid crystal orientation can be improved by this. In the latter case, the planarity of the polyamic acid or the like decreases due to the group adjacent to the amino group, thereby improving the solubility of the polymer in the organic solvent. From the viewpoint of maintaining the planarity moderately, the group adjacent to the amino group is preferably one having 1 to 3 carbon atoms, and among these, a methyl group or an ethyl group is particularly preferable.

Specific examples of the compound represented by the formula (D-1) include 4-aminophenyl-4'-aminobenzoate, 3,3'-dimethyl-4-aminophenyl-4'-aminobenzoate, 3,3 ', 5,5'-tetramethyl-4-aminophenyl-4'-aminobenzoate and 3-methyl-4-aminophenyl-4'-aminobenzoate are preferred, and among these, 4-aminophenyl-4 ' Aminobenzoate is preferred.

As a diamine for synthesize | combining the polyamic acid in this invention, only the compound represented by said formula (D-1) may be used, and other diamine may be used together with the compound represented by said formula (D-1).

As other diamine which can be used here, an aliphatic diamine, alicyclic diamine, aromatic diamine, diamino organosiloxane, etc. are mentioned, for example. As these specific examples, As an aliphatic diamine, For example, 1,1-methyylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, etc .;

As alicyclic diamine, For example, 1, 4- diamino cyclohexane, 4, 4'- methylenebis (cyclohexylamine), 1, 3-bis (aminomethyl) cyclohexane, etc .;

As aromatic diamine, for example, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'- diaminodiphenylmethane, 4,4'- diaminodiphenyl sulfide, 1, 5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 2,7- Diaminofluorene, 4,4'-diaminodiphenylether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2 , 2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-phenylenediisopropylidene ) Bisaniline, 4,4 '-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl , 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3, 6-diaminocarbazole, N- Tyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N'-bis (4-aminophenyl) -benzidine, N, N'-bis (4-aminophenyl ) -N, N'-dimethylbenzidine, 1,4-bis- (4-aminophenyl) -piperazine, 3,5-diaminobenzoic acid, dodecaneoxy-2,4-diaminobenzene, tetradecaneoxy- 2,4-diaminobenzene, pentadecaneoxy-2,4-diaminobenzene, hexadecaneoxy-2,4-diaminobenzene, octadecaneoxy-2,4-diaminobenzene, dodecaneoxy-2, 5-diaminobenzene, tetradecaneoxy-2,5-diaminobenzene, pentadecaneoxy-2,5-diaminobenzene, hexadecaneoxy-2,5-diaminobenzene, octadecaneoxy-2,5- Diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2, 4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5-diaminobenzoic acid cholestenyl, 3,5-diaminobenzoic acid ranostanyl, 3,6-bis (4 -Aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4'-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 4- (4'-trifluoromethylbenzoyloxy) cyclohexyl-3,5-diaminobenzoate, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1 -Bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, 1,1- Bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, 2,4-diamino-N, N-diallylaniline, 4-aminobenzylamine, 3-amino Benzylamine, 1- (2,4-diaminophenyl) piperazin-4-carboxylic acid, 4- (morpholin-4-yl) benzene-1,3-diamine, 1,3-bis (N- (4 -Aminophenyl) piperidinyl) propane, α-amino-ω-aminophenylalkylene and the following formula (A-1):

^Wherein X ^I and X ^II each represent a single bond, * -O-, * -COO- or * -OCO- (wherein the bond to which "*" is attached is bonded to the benzene ring), and R ¹ Is a single bond, a methylene group or an alkylene group having 2 or 3 carbon atoms, a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, n is 0 or 1; a and b are never zero at the same time)

Compounds represented by these;

Examples of the diaminoorganosiloxanes include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and the like, and the diamines described in JP-A 2010-97188 are other than those described above. Can be used.

The formula (A-1) in the -X -R ^{Ⅰ Ⅰ} -X ^Ⅱ In -alkyl As the divalent group represented by a methylene group, having 2 or 3 groups, * -O-, * -COO- or * - It is preferable that O-CH ₂ CH ₂ -O- (wherein the bond to which "*" is attached is bonded to a diaminophenyl group). As a specific example of group "-C _{C H2C + 1} ", for example, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group , n-nonyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octade A practical group, n-nonadecyl group, n-eicosyl group, etc. are mentioned. It is preferable that two amino groups in a diaminophenyl group exist in 2, 4-position or 3, 5-position with respect to another group.

As a specific example of a compound represented by said formula (A-1), the compound etc. which are represented by each of following formula (A-1-1) (A-1-3) are mentioned, for example.

It is preferable that the ratio of the compound represented by said formula (D-1) is 10-100 mol% with respect to the whole amount of diamine. By making it into the said range, even if an aliphatic or alicyclic thing is used as tetracarboxylic dianhydride, the liquid crystal aligning film which can express the outstanding liquid crystal alignability can be formed, making the voltage retention of a liquid crystal favorable.

<Molecular weight regulator>

When synthesize | combining a polyamic acid, you may make it synthesize | combine a terminal-modified polymer using a suitable molecular weight modifier with tetracarboxylic dianhydride and diamine as mentioned above. By setting it as such a terminal modified polymer, the coating property (printability) of a liquid crystal aligning agent can be improved further, without impairing the effect of this invention.

As a molecular weight modifier, an acid monoanhydride, a monoamine compound, a monoisocyanate compound, etc. are mentioned, for example. As these specific examples, examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride, and the like. of;

As a monoamine compound, For example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, etc .;

As a monoisocyanate compound, phenyl isocyanate, naphthyl isocyanate, etc. are mentioned, respectively.

It is preferable to set it as 20 weight part or less with respect to a total of 100 weight part of tetracarboxylic dianhydride and diamine to be used, and, as for the usage ratio of a molecular weight modifier, it is more preferable to set it as 10 weight part or less.

Synthesis of Polyamic Acid

The use ratio of tetracarboxylic dianhydride and diamine to be used for the polyamic acid synthesis reaction is preferably a ratio in which the acid anhydride group of tetracarboxylic dianhydride is 0.2 to 2 equivalents relative to 1 equivalent of the amino group of the diamine. The ratio which becomes 1.2 equivalent is more preferable.

The synthesis reaction of polyamic acid is preferably performed in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C. Moreover, 0.1-24 hours are preferable and, as for reaction time, 0.5-12 hours are more preferable.

Here, examples of the organic solvent include aprotic polar solvents, phenols and derivatives thereof, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like.

As specific examples of these organic solvents, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetoamide, N, N-dimethylformamide, dimethyl sulfoxide, γ- Butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like;

As said phenol derivative, For example, m-cresol, xylenol, a halogenated phenol etc .;

As said alcohol, For example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1, 4- butanediol, triethylene glycol, ethylene glycol monomethyl ether, etc .;

As said ketone, For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc .;

As said ester, For example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, diethyl malonate, etc .;

Examples of the ether include 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, tetra Hydrofuran and the like;

Examples of the halogenated hydrocarbons include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;

Examples of the hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, isoamyl isobutylate, diisopentyl ether, and the like.

Among these organic solvents, at least one selected from the group consisting of aprotic polar solvents and phenols and derivatives thereof (first group of organic solvents), or at least one type selected from the first group of organic solvents, Preference is given to using mixtures with at least one member selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group of organic solvents). In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, and more preferably 40% by weight or less with respect to the total of the organic solvent of the first group and the organic solvent of the second group. More preferably, it is 30 weight% or less.

It is preferable to make the usage-amount of organic solvent (a) into the amount which will be 0.1-50 weight% with respect to the total amount (a + b) of the total amount (b) of tetracarboxylic dianhydride and diamine.

As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for preparation of a liquid crystal aligning agent, and may be used for preparation of a liquid crystal aligning agent after isolating the polyamic acid contained in a reaction solution. Or after refine | purifying an isolated polyamic acid, you may provide for preparation of a liquid crystal aligning agent. Isolation and purification of polyamic acid can be performed according to a well-known method.

<Imidated Polymer>

The imidation polymer (polyimide) in this invention can be obtained by dehydrating and ring-closing the synthesized polyamic acid and imidizing it. In this case, the reaction solution formed by dissolving polyamic acid may be used as it is for dehydration ring-closure reaction as it is, or after isolation of polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction.

The polyimide in the present invention may be a complete imide obtained by dehydrating and ring-closing the entire dark acid structure possessed by the polyamic acid as its precursor, or by dehydrating and ring-closing only a part of the dark acid structure to coexist with the dark acid structure and the imide ring structure. Imide may be sufficient. It is preferable that the imidation ratio of the polyimide in this invention is 30% or more, It is more preferable that it is 50 to 99%, It is more preferable that it is 65 to 99%. This imidation ratio shows the ratio which the number of the imide ring structure to the sum of the number of the dark acid structures of a polyimide, and the number of imide ring structures occupies as a percentage. Here, part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating it as necessary. . Among these, it is preferable by the latter method.

In the method of adding a dehydrating agent and a dehydrating ring-closure catalyst during the dissolution of the polyamic acid, for example, acid anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic anhydride can be used as the dehydrating agent. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of the dark acid structure of polyamic acid. As the dehydration ring closure catalyst, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used, for example. It is preferable that the usage-amount of a dehydration ring-closure catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents used. As an organic solvent used for a dehydration ring-closure reaction, the organic solvent illustrated as what is used for the synthesis | combination of polyamic acid is mentioned. Preferably the reaction temperature of a dehydration ring-closure reaction is 0-180 degreeC, More preferably, it is 10-150 degreeC. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

In this way, a reaction solution containing a polyimide is obtained. This reaction solution may be provided as it is to preparation of a liquid crystal aligning agent as it is, may be provided to preparation of a liquid crystal aligning agent after removing a dehydrating agent and a dehydration ring-closure catalyst from a reaction solution, and after isolation of a polyimide to preparation of a liquid crystal aligning agent You may provide, or after refine | purifying an isolated polyimide, you may provide for preparation of a liquid crystal aligning agent. These purification operations can be performed according to a well-known method.

<Solution Viscosity of Polymer>

When the polyamic acid and imidation polymer (henceforth a specific polymer) in this invention obtained as mentioned above are made into the solution of 10 weight% of concentration, it is preferable to have a solution viscosity of 20-80 mPa * s, It is more preferable to have a solution viscosity of 30 to 500 mPa · s.

In addition, the solution viscosity (mPa? S) of the polymer is 10 wt% prepared using a good solvent of the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is the value measured at 25 degreeC using the E-type rotational viscometer about% polymer solution.

<Other additives>

Although the liquid crystal aligning agent of this invention contains the specific polymer, you may contain other components as needed. As such other components, other polymers other than the said specific polymer, the compound which has at least 1 epoxy group in a molecule | numerator (henceforth "epoxy compound"), a functional silane compound, etc. are mentioned, for example.

[Other polymers]

The other polymers can be used for improving solution properties and electrical properties. Such other polymers are polymers other than a specific polymer, and for example, polyamic acid and aromatic tetracarboxylic dianhydride obtained by reacting a diamine and a tetracarboxylic dianhydride containing no compound represented by the formula (D-1). Polyamic acid (hereinafter referred to as "other polyamic acid") obtained by reacting with a diamine, polyimide (hereinafter referred to as "other polyimide") obtained by dehydrating and ringing the other polyamic acid, polyamic acid ester, polyester , Polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. Among these, other polyamic acid or other polyimide is preferable, and other polyamic acid is more preferable. Moreover, as tetracarboxylic dianhydride and diamine used for synthesize | combining other polyamic acid and other polyimide, the compound used for synthesize | combining the said specific polymer is mentioned.

When adding another polymer to a liquid crystal aligning agent, 50 weight% or less is preferable with respect to the total amount of polymers in a liquid crystal aligning agent, 0.1-40 weight% is more preferable, and 0.1-30 weight% More preferred.

[Epoxy Compound]

An epoxy compound can be used for the improvement of the mechanical strength in a liquid crystal aligning film. Thereby, peeling of a film | membrane etc. can be suppressed (rubbing tolerance can be improved) at the time of a rubbing process, and also the display defect in a liquid crystal display element can be suppressed. Moreover, an epoxy compound can be used for the purpose of the adhesive improvement of a liquid crystal aligning film and a base material.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Neopentylglycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl Ether, N, N, N ', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N- diglycidyl-benzylamine, N, N- diglycidyl-aminomethylcyclohexane, N, N-di Glycidyl cyclohexylamine etc. are mentioned as a preferable thing.

When adding these epoxy compounds to a liquid crystal aligning agent, 40 weight part or less is preferable with respect to a total of 100 weight part of polymers contained in a liquid crystal aligning agent, and 0.1-30 weight part is more preferable.

[Functional silane compound]

As said functional silane compound, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N- (2 -Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxy Silane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimeth Methoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecan, 10-triethoxysilyl-1,4,7-triazadecan, 9-trimethoxysilyl-3 , 6-Diazonayl acetate, 9-triethoxysilyl-3,6-diazanyl acetate, 9-trimethoxysilyl-3,6-methyl diazanoanoate, 9-triethoxy Methyl-3,6-diazanonan acid, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N -Phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

When adding these functional silane compounds to a liquid crystal aligning agent, 2 weight part or less is preferable with respect to a total of 100 weight part of polymers, and, as for the compounding ratio, 0.02-0.2 weight part is more preferable.

[Organic Solvent]

The liquid crystal aligning agent of this invention is melt | dissolved and contained in a specific polymer, and the other additive arbitrarily blended as needed preferably in an organic solvent, and are comprised.

As an organic solvent used for the liquid crystal aligning agent of this invention, N-methyl- 2-pyrrolidone, (gamma) -butyrolactone, (gamma) -butyrolactam, N, N- dimethylformamide, N, N- Dimethylacetoamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether , Diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, di Isobutyl ketone, isoamyl propionate, isoamyl isobutyrate, di-isopentyl ether, ethylene carbonate, propylene carbonate, and the like. These can be used independently, or can mix and use 2 or more types.

Solid content concentration (the ratio which the total weight of components other than the solvent of a liquid crystal aligning agent occupies in the total weight of a liquid crystal aligning agent) in a liquid crystal aligning agent is selected suitably in consideration of viscosity, volatility, etc., Preferably it is 1-10. It is the range of weight%. That is, the liquid crystal aligning agent of this invention is apply | coated to the surface of a board | substrate as mentioned later, Preferably the coating film which becomes a coating film which is a liquid crystal aligning film, or a liquid crystal aligning film is formed by heating, At this time, when solid content concentration is less than 1 weight%, The film thickness of a coating film becomes small and it is difficult to obtain a favorable liquid crystal aligning film. On the other hand, when solid content concentration exceeds 10 weight%, the film thickness of a coating film becomes excessive and it is difficult to obtain a favorable liquid crystal aligning film, and there exists a possibility that the viscosity of a liquid crystal aligning agent may increase and coating characteristics may fall.

The range of especially preferable solid content concentration changes with the method used when apply | coating a liquid crystal aligning agent to a board | substrate. For example, in the case of a spinner method, the range of 1.5 to 4.5 weight% of solid content concentration is especially preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. When using the inkjet method, it is especially preferable to make solid content concentration into the range of 1 to 5 weight%, and to make solution viscosity into the range of 3-15 mPa * s.

The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC.

<Liquid crystal aligning film and liquid crystal display element>

The liquid crystal aligning film of this invention is formed of said liquid crystal aligning agent. Moreover, the liquid crystal display element of this invention is equipped with the said liquid crystal aligning film. The liquid crystal display element of the present invention may be applied to an operation mode of a horizontal alignment type such as an IPS type, a TN type, an STN type, or an FFS type, or may be applied to an operation mode of a vertical alignment type such as a VA type. It is a horizontal orientation type, Especially, it is preferable to apply to IPS type especially.

While the manufacturing method of the liquid crystal display element of this invention is demonstrated below, the manufacturing method of the liquid crystal aligning film of this invention is demonstrated also in the description. The liquid crystal display element of this invention can be manufactured by the process of the following (1)-(3), for example. In the step (1), the substrate used differs depending on the desired operation mode. Steps (2) and (3) are common to each operation mode.

[Step (1): Formation of Coating Film]

First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, and then a coating film is formed on a board | substrate by heating a coating surface.

(1-1) When manufacturing a TN type, STN type, or VA type liquid crystal display element, two board | substrates with which the patterned transparent conductive film is formed are made into a pair, on this transparent conductive film formation surface, this invention Liquid crystal aligning agent is preferably applied by an offset printing method, a spin coating method, a roll coating method or an inkjet printing method, and then each coated surface is heated (preferably preheated (prebaked) and fired (postbaking). ) Is formed, thereby forming a coating film. Here, as a board | substrate, For example, glass, such as a float glass and a soda glass; The transparent substrate which consists of plastics, such as a polyethylene terephthalate, a polybutylene terephthalate, a polyether sulfone, a polycarbonate, and a poly (alicyclic olefin), can be used. As the transparent conductive film formed on one surface of the substrate, an NESA film (registered trademark of PPG Co., Ltd.) made of tin oxide (SnO ₂ ), an ITO film made of indium tin oxide (In ₂ O ₃ -SnO ₂ ), or the like can be used. In order to obtain a patterned transparent conductive film, for example, after forming a patternless transparent conductive film, forming a pattern by photo-etching, using a mask having a desired pattern when forming the transparent conductive film, or the like You can. When apply | coating a liquid crystal aligning agent, in order to make adhesiveness of a board | substrate surface and a transparent conductive film and a coating film more favorable, a functional silane compound, a functional titanium compound, etc. are previously made to the surface which should form a coating film in the board | substrate surface. Pretreatment to apply may be performed.

The coating surface after a liquid crystal aligning agent application | coating is then preheated (prebaked), and further baked (postbaking) is formed. Prebaking conditions are 0.1-5 minutes, for example at 40-120 degreeC, Post-baking conditions are preferably 120-300 degreeC, More preferably, it is 150-250 degreeC, Preferably it is 5-200 minutes, More preferably, it is 10-100 minutes. The film thickness of the formed coating film becomes like this. Preferably it is 0.001-1 micrometer, More preferably, it is 0.005-0.5 micrometer.

(1-2) On the other hand, when manufacturing an IPS type | mold liquid crystal display element, this invention is carried out on the electrically conductive film formation surface of the board | substrate in which the transparent conductive film patterned by the comb-tooth shape is formed, and the one surface of the opposing board | substrate in which the electrically conductive film is not formed. The liquid crystal aligning agent of each is apply | coated, and then a coating film is formed by heating each application surface. The material used for the substrate and the transparent conductive film at this time, the coating method, the heating conditions after coating, the patterning method of the transparent conductive film, the pretreatment of the substrate, and the preferred film thickness of the formed coating film are the same as in the above (1-1).

In any of said (1-1) and (1-2), after apply | coating a liquid crystal aligning agent on a board | substrate, the coating film used as an oriented film is formed by removing an organic solvent. At this time, when the polymer contained in the liquid crystal aligning agent of this invention is a polyamic acid or the imidized polymer which has an imide ring structure and a dark acid structure, it heats further after coating film formation, and advances dehydration ring-closure reaction, and is already It is good also as a drawing coating film.

[Step 2: Rubbing Treatment]

When manufacturing a TN type, STN type, or IPS type liquid crystal display element, the rubbing process which rubs the coating film formed at the said process (1) in the fixed direction with the roll wound the cloth which consists of fibers, such as nylon, rayon, and cotton, for example. To be implemented. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film.

Moreover, the process of changing the pretilt angle of the some area | region of a liquid crystal aligning film by irradiating a part of liquid crystal aligning film with an ultraviolet-ray with respect to said liquid crystal aligning film, or after forming a resist film in a part of the surface of a liquid crystal aligning film, differs from the previous rubbing process. After performing a rubbing process in a direction, the process of removing a resist film may be performed and a liquid crystal aligning film may have a different liquid crystal aligning ability for every area | region. In this case, it is possible to improve the field of view characteristic of the liquid crystal display element obtained.

In addition, when manufacturing a VA type liquid crystal display element, although the coating film formed in the said process (1) can be used as a liquid crystal aligning film as it is, you may perform a rubbing process with respect to the said coating film.

[Step (3): Construction of Liquid Crystal Cell]

With respect to the pair of substrates in which the liquid crystal alignment films are formed as described above, the substrates are disposed to face each other via a gap (cell gap) such that the rubbing direction of the liquid crystal alignment films of the two substrates is perpendicular or antiparallel, and the two peripheral portions of the substrate are sealed. Using a bonding agent, the liquid crystal is injected and filled into the cell gap partitioned by the substrate surface and the sealing agent, and the injection hole is sealed to form a liquid crystal cell. And a liquid crystal display element can be obtained by bonding a polarizing plate to the outer surface of a liquid crystal cell so that the polarization direction may coincide or orthogonally cross with the rubbing direction of the liquid crystal aligning film formed in each board | substrate.

As the sealing agent, for example, an epoxy resin containing aluminum oxide spheres as a curing agent and a spacer can be used.

Examples of the liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable, and for example, a sieve base liquid crystal, a subfamily clock liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal and an ester liquid crystal , Terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, kuban-based liquid crystal and the like can be used. Moreover, for these liquid crystals, For example, cholesteric liquid crystals, such as cholesteryl chloride, cholesteryl nonaate, cholesteryl carbonate; Chiral agent sold as brand names "C-15" and "CB-15" (made by Merck); Ferroelectric liquid crystals, such as p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate, may be added and used.

As a polarizing plate bonded to the outer surface of a liquid crystal cell, the polarizing plate which consists of a polarizing plate called "H film" which absorbed iodine while extending | stretching polyvinyl alcohol, and sandwiched between the cellulose acetate protective films, or the H film itself is mentioned. .

The liquid crystal display element of this invention can be effectively applied to various apparatuses, For example, a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, various monitors And a display device such as a liquid crystal television.

(Example)

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

In addition, the solution viscosity of the polymer in each following synthesis examples is the value measured at 25 degreeC using the E-type rotational viscometer. In addition, the imidation ratio of the polyimide was measured as follows.

[Imidation Rate of Polyimide]

The solution of polyimide was put into distilled water, the obtained precipitate was dried under reduced pressure sufficiently at room temperature, dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. H-NMR spectrum obtained from the ^first, to the imidization ratio was calculated according to the equation represented by the formula (1).

Imidation ratio (%) = (1-A ¹ / A ² × α) × 100. (One)

(In Formula (1), A <^1> is the peak area derived from the proton of the NH group which shows around 10 ppm of chemical shifts, A <^2> is the peak area derived from other protons, and (alpha) is a precursor (polyamic acid) of a polymer. It is the number ratio of the other protons to one proton of NH group.

Synthesis of Polymer

[Synthesis Examples 1-9 and Comparative Synthesis Examples 1-11]

Diamine and tetracarboxylic dianhydride in the amounts shown in Table 1 below were added to N-methyl-2-pyrrolidone in this order to obtain a solution having a monomer concentration of 15% by weight. Then, reaction was performed at room temperature for 6 hours, and the solution containing polyamic acid (PA-1)-(PA-9) and (PAR-1)-(PAR-11) was obtained, respectively. A small amount of each solution was added, and N-methyl-2-pyrrolidone was added to make a solution having a polyamic acid concentration of 10% by weight. The result of having measured the solution viscosity is shown in Table 1 below. In addition, each half amount of these polyamic acid solutions was ensured, and it used respectively in Examples 1-9 and Comparative Examples 1-11 which follow.

In the polyamic acid solution, for (PA-2) to (PA-4) and (PAR-5) to (PAR-7), N-methyl-2-pyrrolidone is added to the remaining half of the solution, It was set as the solution of 6 weight% of polyamic acid concentrations. Here, pyridine and acetic anhydride were added to the molar ratios shown in the following Table 1 with respect to 1 mole of amic acid units each having polyamic acid, and then heated to 110 ° C. for a dehydration ring closure reaction for 4 hours. After the dehydration ring closure reaction, the solvent in the system was substituted with fresh N-methyl-2-pyrrolidone (pyridine and acetic anhydride used in the dehydration ring closure reaction in this operation to the outside of the system) to obtain polyimide (PI-1)? Solutions containing 15% by weight of (PI-3) and (PIR-1) to (PIR-3), respectively, were obtained. When the imidation ratio of each polyimide contained in these polyimide solutions was measured, each solution was aliquoted in small amounts, and when N-methyl-2-pyrrolidone was added and it was set as the solution of 10 weight% of polyimide concentrations, The solution viscosity was measured. Each measurement result is shown in Table 1 below. In addition, these polyimide solutions were used in the following Examples 10-12 and Comparative Examples 12-14, respectively.

In Table 1, the abbreviation of diamine and tetracarboxylic anhydride has the following meanings, respectively.

<Diamine>

d-1: 4-aminophenyl-4'-aminobenzoate

d-2: 4,4'- diamino diphenyl ether

d-3: 4,4'-diaminodiphenylmethane

d-4: 2,2-bis [4- (4-aminophenoxy) phenyl] propane

d-5: p-phenylenediamine

<Tetracarboxylic dianhydride>

t-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB)

t-2: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride

t-3: 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-4: 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1, 3-dion

t-5: (1S, 2S, 4R, 5R) -cyclohexanetetracarboxylic dianhydride

t-6: (1R, 2S, 4S, 5R) -cyclohexanetetracarboxylic dianhydride

t-7: 1,2,3,4-butanetetracarboxylic dianhydride

t-8: pyromellitic dianhydride (PMDA)

(Example 1)

<Preparation of liquid crystal aligning agent>

Γ-butyrolactone (BL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) are added to the solution containing polyamic acid (PA-1) obtained in Synthesis Example 1. Furthermore, as a crosslinking agent (adhesive improvement agent), 10 weight part of N, N, N ', N'- tetraglycidyl-4,4'- diamino diphenylmethane which is an epoxy compound was added, and a solvent ratio was BL: NMP: It was set as BC = 40: 40: 20 (weight ratio) and the solution of 4.0 weight% of solid content concentration. After fully stirring this solution, the liquid crystal aligning agent was prepared by filtering using the filter of 1 micrometer of pore diameters. Let the alignment agent at this time be "with a crosslinking agent," and the thing which did not add N, N, N ', N'- tetraglycidyl-4,4'- diaminodiphenylmethane by said preparation of a liquid crystal aligning agent We assumed "there is no crosslinking system".

<Production and Evaluation of Liquid Crystal Cells>

The liquid crystal cell was produced using this liquid crystal aligning agent, and the following evaluation was performed.

[Production of Liquid Crystal Cell]

The above-mentioned liquid crystal aligning agent was apply | coated with the spinner on the glass substrate of thickness 1mm which has the chrome electrode formed in the comb-tooth shape on one surface, and after prebaking for 1 minute on 80 degreeC hotplate, it is 230 degreeC hot It post-baked for 10 minutes on the plate, and formed the coating film of about 800 micrometers in film thickness. About the formed coating film surface, the rubbing process is performed using the rubbing machine which has the roll wound the cloth of nylon, and the rubbing process is performed by the rotation speed of 1000 rpm of a roll, the movement speed of 25 mm / sec of a stage, and 0.4 mm of a mother-foot indentation length, Granted. Furthermore, this board | substrate was ultrasonically cleaned for 1 minute in ultrapure water, and it dried for 10 minutes in a 100 degreeC clean oven, and the board | substrate which has a liquid crystal aligning film on the surface which has a comb-shaped chrome electrode was manufactured. The board | substrate which has this liquid crystal aligning film was made into "substrate A."

Separately, on one surface of a glass substrate having a thickness of 1 mm without electrodes, a coating film of a liquid crystal aligning agent is formed in the same manner as above, followed by a rubbing treatment, washing and drying to produce a substrate having a liquid crystal alignment film on one surface. did. The board | substrate which has this liquid crystal aligning film was called "substrate B."

Subsequently, after apply | coating the epoxy resin adhesive containing the aluminum oxide sphere of 5.5 micrometers in diameter to the outer edge of the surface which has the rubbing process liquid crystal aligning film of a board | substrate, two sheets are carried out so that the rubbing direction in each liquid crystal aligning film may become antiparallel. The substrates A and B were disposed to face each other via a gap, the outer edge portions were brought into contact with each other, and the adhesive was cured. Subsequently, after filling a nematic liquid crystal (MLC-2042 by Merck Co., Ltd.) between a pair of board | substrates from a liquid crystal injection port, the IPS type liquid crystal cell was manufactured by sealing a liquid crystal injection port with an acryl-type photocuring adhesive.

[Evaluation of Liquid Crystal Display Device]

? Evaluation of liquid crystal orientation

About the liquid crystal cell produced above, it observed using the polarization microscope. Evaluation of the liquid-crystal orientation was performed "good" that the light leak was hardly confirmed, and "good" which the light leak was very slight confirmed as "good" and that the flow orientation and the light leak were clearly confirmed. In addition, about the thing evaluated by liquid crystal aligning property "excellent", it evaluated three steps further and evaluated as 1, 2, 3 in order that liquid crystal alignability is favorable. The results are shown in Table 2 below.

Evaluation of voltage integrity characteristics

The voltage of 1V was applied at 60 degreeC for 30 second about the thing of "with a crosslinking agent" among the liquid crystal cells produced above, and the voltage retention after application | release cancellation was measured at 1V and 60 degreeC by frame period 167msec. The measurement results are shown in Table 2 below. In addition, Table 2 shows the results of the three-stage evaluation of the voltage integrity characteristics together with the value of the voltage integrity ratio, and indicates that the voltage retention ratio is 99% or more, and that 98% or more and less than 99% is ○, and less than 98% are ×. Indicated.

(Examples 2 to 12 and Comparative Examples 1 to 14)

In the said Example 1, except using the solution containing the polymer shown in the said Table 1 as a polymer solution, respectively, it carried out similarly to Example 1, the liquid crystal aligning agent was prepared, the liquid crystal cell was produced, liquid crystal aligning property and voltage preservation. The characteristic was evaluated. The evaluation results are shown in Table 2 below.

In the case of no crosslinking agent, light leakage was hardly confirmed in all of Examples 1-12 about liquid crystal alignability. Among them, in Examples 1, 3, 4, 8, and 10 to 12, even when there was a crosslinking agent, light leakage was hardly confirmed, and it was found that the flow orientation due to the addition of the crosslinking agent hardly occurs. In addition, the voltage retention in the case of having a crosslinking agent was particularly high in Examples 1, 2, 5, 6, and 10.

Especially, in Examples 1 and 10 which used CB alone as tetracarboxylic dianhydride, it was 99.4% or more also about voltage retention, and was especially excellent in the point which can make liquid crystal aligning property and voltage preservation characteristic compatible. In Example 8, which is a mixed system of CB and PMDA, the liquid crystal alignment property was the best among Examples 1 to 12, and the voltage holding ratio was sufficiently higher than that of Examples 1 and 10.

On the other hand, in Comparative Examples 1-10 and 12-14, although voltage retention was equivalent to Examples 1-12, it was inferior to the thing of Examples 1-12 in liquid crystal orientation. In particular, in Comparative Examples 1 to 10 each containing polyamic acid PAR-1 to PAR-10, flow orientation and light leakage were clearly observed when a crosslinking agent was added. In this regard, in PAR-1 to PAR-10, it can be said that the fall of the liquid-crystal orientation is easy to occur by adding a crosslinking agent.

In addition, when using aromatic ring tetracarboxylic dianhydride (comparative example 11), although it was excellent about liquid-crystal orientation, the voltage retention was low as less than 98%.

Claims (8)

As a liquid crystal aligning agent containing at least any of the polyamic acid obtained by making tetracarboxylic dianhydride and diamine react, and its imidation polymer,
The tetracarboxylic dianhydride includes at least one of an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride,
The said diamine contains the compound represented by a following formula (D-1), The liquid crystal aligning agent characterized by the above-mentioned:

(In formula, R <^1> -R <^10> is R <^1> -R <^5>. 1 of R ⁶ and R ¹⁰ 1 is a primary amino group, and the remainder is a hydrogen atom, a fluorine atom, or a C1-C6 alkyl group, an alkoxy group, or a fluoroalkyl group each independently). The method of claim 1,
The aliphatic tetracarboxylic dianhydride is 1,2,3,4-butane tetracarboxylic dianhydride,
The alicyclic tetracarboxylic dianhydride is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride, 1,3,3a, 4,5, 9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a , 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione, bicyclo [3, A liquid crystal aligning agent which is at least 1 sort (s) chosen from the group which consists of a 3,0] octane-2,4,6,8- tetracarboxylic dianhydride and cyclohexane tetracarboxylic dianhydride. The method of claim 1,
The said tetracarboxylic dianhydride is a liquid crystal aligning agent which is a mixture of at least any of the said aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. 4. The method according to any one of claims 1 to 3,
The alicyclic tetracarboxylic dianhydride is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, (1S, 2S, 4R, 5R) -cyclohexanetetracarboxylic dianhydride, (1R, 2S, 4S The liquid crystal aligning agent which is at least 1 sort (s) chosen from the group which consists of a (5R) -cyclohexane tetracarboxylic dianhydride and 2,3,5- tricarboxy cyclopentyl acetic dianhydride. The liquid crystal aligning film formed with the liquid crystal aligning agent in any one of Claims 1-3. The liquid crystal display element provided with the liquid crystal aligning film of Claim 5. Polyamic acid obtained by making at least any of aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride react with the diamine represented by following formula (D-1):

(In formula, R <^1> -R <^10> is R <^1> -R <^5>. 1 of R ⁶ and R ¹⁰ 1 is a primary amino group, and the remainder is a hydrogen atom, a fluorine atom, or a C1-C6 alkyl group, an alkoxy group, or a fluoroalkyl group each independently). The polyimide obtained by imidating the polyamic acid of Claim 7.