JP6409494B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element.

  2. Description of the Related Art Conventionally, as liquid crystal display elements, various drive systems having different electrode structures and physical properties of liquid crystal molecules to be used have been developed. For example, TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA Various liquid crystal display elements such as (Vertical Alignment) type, IPS (In-Plane Switching) type, FFS (fringe field switching) type, and optical compensation bent type (OCB type) are known. These liquid crystal display elements have a liquid crystal alignment film for aligning liquid crystal molecules. As a material for the liquid crystal alignment film, polyamic acid, polyimide, polyorganosiloxane, and the like are used because they have various properties such as heat resistance, mechanical strength, and affinity with liquid crystal.

  The liquid crystal aligning agent is usually prepared as a liquid composition in which a polymer component is dissolved in a solvent, and the liquid composition is applied to a substrate and heated to form a liquid crystal alignment film. Here, as a solvent for the liquid crystal aligning agent, an aprotic polar solvent such as N-methyl-2-pyrrolidone or γ-butyrolactone is generally used in order to uniformly dissolve the polymer. In addition, as a solvent, for the purpose of improving the applicability (printability) of the liquid crystal aligning agent when the liquid crystal aligning agent is applied to the substrate, surface tension such as butyl cellosolve is used together with the aprotic polar solvent. A relatively low organic solvent is used in combination (see, for example, Patent Document 1 and Patent Document 2).

JP 2010-97188 A JP 2010-156934 A

  In recent years, the demand for higher performance of liquid crystal display elements has further increased, and a liquid crystal that exhibits better coating properties and better reliability than butyl cellosolve that is generally used to improve the coating properties of liquid crystal alignment agents. Development of a liquid crystal aligning agent capable of obtaining a display element is desired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal aligning agent that can obtain a highly reliable liquid crystal display element with good applicability.

  As a result of intensive studies to achieve the above-described problems of the prior art, the present inventor has found that the above-mentioned problems can be solved by including a specific compound as a solvent component of the liquid crystal aligning agent. It came to complete. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element.

  In one aspect, the present invention contains at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester, polyimide and polyorganosiloxane, and a solvent, wherein the solvent is 2-butoxy A liquid crystal aligning agent containing 0.1 to 50% by weight of -1-propanol with respect to the total amount of solvent is provided.

  In another aspect, the present invention provides a liquid crystal alignment film formed using the liquid crystal alignment agent. In another aspect, a liquid crystal display device comprising the liquid crystal alignment film is provided.

  The liquid crystal aligning agent has good applicability to the substrate. Moreover, according to the liquid crystal aligning agent, a highly reliable liquid crystal display element can be obtained.

  Below, each component contained in the liquid crystal aligning agent which concerns on this invention, and the other component arbitrarily mix | blended as needed are demonstrated.

<Polymer (A)>
The liquid crystal aligning agent according to the present invention contains at least one polymer (A) selected from the group consisting of polyamic acid, polyimide, polyamic acid ester, and polyorganosiloxane.
[Polyamic acid]
The polyamic acid according to the present invention can be obtained by reacting tetracarboxylic dianhydride and diamine.

（式（Ｂ−１）中、Ｘ^１及びＸ^２は、それぞれ独立に単結合、酸素原子、硫黄原子、−ＣＯ−、＊−ＣＯＯ−、＊−ＯＣＯ−、＊−ＣＯ−ＮＲ^２−、＊−ＮＲ^２−ＣＯ−（ただし、Ｒ^２は水素原子又は炭素数１〜６の１価の炭化水素基である。「＊」は、Ｒ^１との結合手を示す。）である。Ｒ^１は、炭素数１〜１０のアルカンジイル基、当該アルカンジイル基の炭素−炭素結合間に−Ｏ−を含む２価の基、シクロヘキシレン基、フェニレン基又はビフェニレン基である。）
などを；それぞれ挙げることができるほか、特開２０１０−９７１８８号公報に記載のテトラカルボン酸二無水物を用いることができる。 (Tetracarboxylic dianhydride)
Examples of tetracarboxylic dianhydrides used for the synthesis of polyamic acid include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, and the like. . Specific examples thereof include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-di Oxotetrahydrofuran-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl) -8 -Methyl-3a, 4,5,9b-tetrahydronaphtho [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-To Carboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride and the like;
Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, and the following formula (B-1)

(In Formula (B-1), X ¹ and X ² are each independently a single bond, an oxygen atom, a sulfur atom, —CO—, * —COO—, * —OCO—, * —CO—NR ² —, * —NR ² —CO— (wherein R ² is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, “*” represents a bond to R ¹ ). ¹ is an alkanediyl group having 1 to 10 carbon atoms, a divalent group containing —O— between carbon-carbon bonds of the alkanediyl group, a cyclohexylene group, a phenylene group, or a biphenylene group.
In addition, the tetracarboxylic dianhydrides described in JP 2010-97188 A can be used.

なお、上記テトラカルボン酸二無水物は、１種を単独で又は２種以上組み合わせて使用することができる。 Specific examples of the alkanediyl group having 1 to 10 carbon atoms of R ¹ in the formula (B-1) include, for example, a methylene group, an ethylene group, a propylene group, a butanediyl group, a pentanediyl group, a hexanediyl group, a heptanediyl group, and octane. A diyl group, a nonanediyl group, a decanediyl group, etc. are mentioned. In the divalent group containing —O— between the carbon-carbon bonds of the alkanediyl group, the number of oxygen atoms may be one or two or more.
Specific examples of the compound represented by the formula (B-1) include compounds represented by the following formulas (B-1-1) to (B-1-6).

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

  The tetracarboxylic dianhydride used for the synthesis includes 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dihydrate from the viewpoint of affinity with liquid crystal and the like. Anhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5 -Dioxotetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, bicyclo [3.3.0] octane-2 , 4,6,8-tetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), It is preferable to contain at least one compound selected from the group consisting of lomellitic dianhydride and a compound represented by the above formula (B-1). The amount of these preferred tetracarboxylic dianhydrides used (the total amount when two or more are used) is 5 mol% or more based on the total amount of tetracarboxylic dianhydrides used for the synthesis of polyamic acid. Preferably, the content is 10 mol% or more, more preferably 20 mol% or more.

(Diamine)
Examples of the diamine used for the synthesis of the polyamic acid include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Specific examples of these diamines include aliphatic diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and 1,3-bis (aminomethyl) cyclohexane. ;
Examples of alicyclic diamines include 1,4-diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine) and the like;

（式（Ｅ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、＊−ＣＯＯ−又は＊−ＯＣＯ−（ただし、「＊」はＸ^Ｉとの結合手を示す。）であり、Ｒ^Ｉは炭素数１〜３のアルカンジイル基であり、Ｒ^ＩＩは単結合又は炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｄは０又は１である。但し、ａ及びｂが同時に０になることはない。）
で表される化合物などの配向性基含有ジアミン： Examples of aromatic diamines include dodecanoxydiaminobenzene, tetradecanoxydiaminobenzene, pentadecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, and cholesteryloxydiaminobenzene. Cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostannyl diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 1,1-bis (4 -((Aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((amino Phenoxy Methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, N- (2,4-diaminophenyl) -4 -(4-Heptylcyclohexyl) benzamide, the following formula (E-1)

(In Formula (E-1), X ^I and X ^II are each independently a single bond, —O—, * —COO— or * —OCO— (where “*” represents a bond with X ^I). R ^I is an alkanediyl group having 1 to 3 carbon atoms, R ^II is a single bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, and b is 0 ) Is an integer of ˜2, c is an integer of 1 to 20, and d is 0 or 1. However, a and b are not 0 at the same time.)
Oriented group-containing diamine such as a compound represented by:

p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 4-aminophenyl-4′-aminobenzoate, 4,4′-diaminoazobenzene, 1,5-bis (4-amino) Phenoxy) pentane, 1,7-bis (4-aminophenoxy) heptane, bis [2- (4-aminophenyl) ethyl] hexanedioic acid, N, N-bis (4-aminophenyl) methylamine, 1,5 -Diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 2,7-diaminofluorene, 4,4 ' -Diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) Fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 ′-(p-phenylenediisopropylidene) Bisaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl and the like;
Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; and the diamines described in JP-A 2010-97188 can be used.

Examples of the divalent group represented by “—X ^I — (R ^I —X ^II ) _d —” in the above formula (E-1) include alkanediyl groups having 1 to 3 carbon atoms, * —O—, * —COO— or * —O—C ₂ H ₄ —O— (however, a bond marked with “*” is bonded to a diaminophenyl group) is preferred. Examples of the group “—C _c H _{2c + 1} ” include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group. Group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group and the like, and these are preferably linear. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position with respect to other groups.

Specific examples of the compound represented by the formula (E-1) include, for example, compounds represented by the following formulas (E-1-1) to (E-1-4).

  When applying to a liquid crystal aligning agent for a TN type, STN type or vertical alignment type liquid crystal display element, a group (liquid crystal aligning group) capable of imparting liquid crystal aligning ability to the coating film is introduced into the side chain of the polyamic acid. May be. Examples of the liquid crystal aligning group include an alkyl group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, an alkoxy group having 4 to 20 carbon atoms, a group having a steroid skeleton having 17 to 51 carbon atoms, and a polycyclic ring. Examples thereof include a group having a structure. The polyamic acid having a liquid crystal alignment group can be obtained, for example, by polymerization including an alignment group-containing diamine in the monomer composition. When using orientation group containing diamine, it is preferable that the compounding quantity shall be 3 mol% or more with respect to all the diamines used for a synthesis | combination from a liquid crystal aligning viewpoint, and shall be 5-70 mol%. Is more preferable.

  In addition to the above, the diamine used for the synthesis of the polyamic acid is at least one structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group (hereinafter also referred to as “nitrogen-containing structure”). And a diamine having a carboxyl group. A polymer using a diamine having a nitrogen-containing structure as at least a part of the raw material is preferable in that the effect of improving the reliability of the liquid crystal display element can be enhanced. Moreover, the polymer using the carboxyl group-containing diamine as at least a part of the raw material is preferable in that the effect of improving the applicability (printability) of the liquid crystal aligning agent can be enhanced.

（式（Ｎ−１）中、Ｒ^３は水素原子又は炭素数１〜１０の１価の炭化水素基である。「＊」は炭化水素基に結合する結合手である。） In the diamine having a nitrogen-containing structure, examples of the nitrogen-containing heterocyclic ring that the diamine may have include pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, Examples include isoquinoline, naphthyridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine and the like. Among them, it is preferable to have at least one selected from the group consisting of pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole and acridine.
The secondary amino group and the tertiary amino group that the diamine having a nitrogen-containing structure may have are represented, for example, by the following formula (N-1).

(In Formula (N-1), R ³ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. “*” Is a bond bonded to the hydrocarbon group.)

In the above formula (N-1), examples of the monovalent hydrocarbon group for R ³ include an alkyl group such as a methyl group, an ethyl group, and a propyl group; a cycloalkyl group such as a cyclohexyl group; a phenyl group, a methylphenyl group, and the like And aryl groups. R ³ is preferably a hydrogen atom or a methyl group.

Specific examples of the diamine having a nitrogen-containing structure include, for example, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diamino. Carbazole, 1,4-bis- (4-aminophenyl) -piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N, N ′ -Bis (4-aminophenyl) -benzidine, N, N'-bis (4-aminophenyl) -N, N'-dimethylbenzidine, the following formula (D-2-1) to formula (D-2-6) The compound etc. which are represented by each of these are mentioned.

  In the synthesis of the polyamic acid, the proportion of the diamine having a nitrogen-containing structure is 0.1 mol% or more based on the total amount of the diamine used for the synthesis from the viewpoint of sufficiently obtaining the reliability improvement effect of the liquid crystal display element. Preferably, the content is 1 mol% or more, more preferably 2 mol% or more. Further, the upper limit of the use ratio is preferably 60 mol% or less, more preferably 50 mol% or less, and further preferably 40 mol% or less. In addition, the diamine which has a nitrogen-containing structure can be used individually by 1 type or in combination of 2 or more types.

（式（Ｃ−１）中、Ｘ^４は単結合、酸素原子又は炭素数１〜３のアルカンジイル基である。ｍ１及びｍ２は、それぞれ独立に０又は１である。） As the carboxyl group-containing diamine, for example, a compound represented by the following formula (C-1) can be preferably used.

(In formula (C-1), X ⁴ is a single bond, an oxygen atom or an alkanediyl group having 1 to 3 carbon atoms. M1 and m2 are each independently 0 or 1.)

Specific examples of the compound represented by the above formula (C-1) include 3,5-diaminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, and 4,4′-diaminobiphenyl. Monocarboxylic acids such as -3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid;
4,4′-diaminobiphenyl-3,3′-dicarboxylic acid, 4,4′-diaminobiphenyl-2,2′-dicarboxylic acid, 3,3′-diaminobiphenyl-4,4′-dicarboxylic acid, 3, 3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, 4,4 And dicarboxylic acids such as' -diaminodiphenyl ether-3,3'-dicarboxylic acid;

  In the synthesis of the polyamic acid, the proportion of the carboxyl group-containing diamine may be 1 mol% or more based on the total amount of the diamine used in the synthesis, from the viewpoint of sufficiently obtaining the effect of improving the coatability by using the diamine. It is preferably 5 mol% or more, more preferably 10 mol% or more. In addition, the upper limit value of the usage rate is not particularly limited, but from the viewpoint of voltage holding ratio, it is preferably 80 mol% or less, and preferably 70 mol% or less with respect to the total amount of diamine used for synthesis. Is more preferable. In addition, a carboxyl group-containing diamine can be used by selecting one of the above alone or by appropriately selecting two or more.

（式（４）中、Ｘ^３は、硫黄原子、酸素原子又は−ＮＨ−である。「＊」はそれぞれ結合手を示す。但し、２つの「＊」のうち少なくとも一つは芳香環に結合している。）
で表される部分構造を基本骨格として含有するエステル基含有構造、等が挙げられる。 When providing the liquid crystal aligning ability with the photo-alignment method with respect to the coating film formed with the liquid crystal aligning agent, you may use the polymer which has a photo-alignment structure as at least one part of a polymer (A). As a specific example of the photoalignment structure, a group exhibiting photoalignment by photoisomerization, photodimerization, photolysis, or the like can be employed. Specifically, for example, an azo-containing group containing an azo compound or derivative thereof as a basic skeleton, a cinnamic acid-containing group containing cinnamic acid or a derivative thereof as a basic skeleton, or a chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton A benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, a cyclobutane-containing structure containing cyclobutane or a derivative thereof as a basic skeleton, bicyclo [2.2.2 ] Bicyclo [2.2.2] octene-containing structure containing octene or a derivative thereof as a basic skeleton, the following formula (4)

(In Formula (4), X ³ is a sulfur atom, an oxygen atom or —NH—. “*” Represents a bond, respectively, provided that at least one of two “*” is bonded to an aromatic ring. doing.)
An ester group-containing structure containing a partial structure represented by the above as a basic skeleton, and the like.

  The polyamic acid having a photoalignment structure can be obtained, for example, by polymerization containing at least one of a tetracarboxylic dianhydride having a photoalignment structure and a diamine having a photoalignment structure as a raw material. In this case, from the viewpoint of photoreactivity, the proportion of the monomer having a photo-alignment structure is preferably 20 mol% or more with respect to the total amount of monomers used for polymer synthesis, and is 30 to 80 mol. % Is more preferable.

(Synthesis of polyamic acid)
The polyamic acid can be obtained by reacting the tetracarboxylic dianhydride and diamine as described above with a molecular weight modifier as necessary. The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the tetracarboxylic dianhydride acid anhydride group to 1 equivalent of the amino group of the diamine. The ratio which becomes an equivalent is preferable, and the ratio which becomes 0.3-1.2 equivalent is more preferable.

  Examples of the molecular weight modifier include acid monoanhydrides such as maleic anhydride, phthalic anhydride and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. Can be mentioned. The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used.

The polyamic acid synthesis reaction is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.
Examples of the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like. Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and a phenolic solvent (first group organic solvent), or one or more selected from the first group of organic solvents And a mixture of at least one selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second-group organic solvent). In the latter case, the proportion of the second group organic solvent used is preferably 50% by weight or less, more preferably 40% by weight, based on the total amount of the first group organic solvent and the second group organic solvent. Or less, more preferably 30% by weight or less.

  Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. And at least one selected from the group consisting of halogenated phenols is used as a solvent, or a mixture of one or more of these and another organic solvent is preferably used in the above range. Examples of other organic solvents used at this time include butyl cellosolve, 2-butoxy-1-propanol, and diethylene glycol diethyl ether. The amount of organic solvent used (a) is such that the total amount (b) of tetracarboxylic dianhydride and diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. Is preferred.

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. Isolation and purification of the polyamic acid can be performed according to known methods.

[Polyamic acid ester]
The polyamic acid ester according to the present invention includes, for example, [I] a method of reacting the polyamic acid obtained by the above synthesis reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester and diamine, [III It can be obtained by a method of reacting a tetracarboxylic acid diester dihalide with a diamine.
In this specification, “tetracarboxylic acid diester” means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are carboxyl groups. “Tetracarboxylic acid diester dihalide” means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are halogenated.

  Examples of the esterifying agent used in Method [I] include a hydroxyl group-containing compound, an acetal compound, a halide, an epoxy group-containing compound, and the like. Specific examples thereof include hydroxyl group-containing compounds such as alcohols such as methanol, ethanol and propanol; phenols such as phenol and cresol; and acetal compounds such as N, N-dimethylformamide diethyl acetal, N, N-diethylformamide diethyl acetal and the like; halides such as methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane and the like; epoxy group-containing Examples of the compound include propylene oxide.

  The tetracarboxylic acid diester used in the method [II] can be obtained, for example, by ring-opening the tetracarboxylic dianhydride exemplified in the synthesis of the polyamic acid with alcohols such as methanol and ethanol. Examples of the diamine used in Method [II] include the diamines exemplified in the synthesis of polyamic acid. The reaction of Method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. As an organic solvent, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. Examples of the dehydration catalyst include 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium halide, carbonylimidazole, a phosphorus condensing agent, and the like. The reaction temperature at this time is preferably -20 to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.

  The tetracarboxylic acid diester dihalide used in Method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with an appropriate chlorinating agent such as thionyl chloride. Examples of the diamine used in Method [III] include the diamines exemplified in the synthesis of polyamic acid. The reaction of Method [III] is preferably carried out in an organic solvent in the presence of a suitable base. As an organic solvent, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. As the base, for example, tertiary amines such as pyridine and triethylamine; alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium and potassium can be preferably used. The reaction temperature at this time is preferably -20 to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.

  The polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. In addition, the reaction solution formed by dissolving the polyamic acid ester may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid ester contained in the reaction solution. Alternatively, the isolated polyamic acid ester may be purified and then used for the preparation of the liquid crystal aligning agent. Isolation and purification of the polyamic acid ester can be performed according to a known method.

[Polyimide]
Polyimide can be obtained, for example, by dehydrating and ring-closing imidized polyamic acid synthesized as described above.

  The polyimide may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure possessed by the polyamic acid that is the precursor, and only a part of the amic acid structure may be dehydrated and cyclized. It may be a partially imidized product in which a ring structure coexists. The polyimide used for the reaction preferably has an imidization ratio of 20% or more, more preferably 30 to 99%, and still more preferably 40 to 99%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, a part of the imide ring may be an isoimide ring.

  The polyamic acid is preferably dehydrated and closed by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, and heating the solution as necessary. . Of these, the latter method is preferred.

  In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to a polyamic acid solution, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. It is preferable that the usage-amount of a dehydrating agent shall be 0.01-20 mol with respect to 1 mol of the amic acid structure of a polyamic acid. As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. It is preferable that the usage-amount of a dehydration ring-closing catalyst shall be 0.01-10 mol with respect to 1 mol of dehydrating agents to be used. Examples of the organic solvent used in the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of polyamic acid. The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

  In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used for the preparation of the liquid crystal aligning agent as it is, may be used for the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution, and the liquid crystal after isolating the polyimide. You may use for preparation of an aligning agent, or you may use for preparation of a liquid crystal aligning agent, after purifying the isolated polyimide. These purification operations can be performed according to known methods. In addition, polyimide can also be obtained by imidation of polyamic acid ester.

  The polyamic acid, the polyamic acid ester, and the polyimide as the polymer (A) obtained as described above have a solution viscosity of 10 to 800 mPa · s when this is a 10% by weight solution. It is preferable to have a solution viscosity of 15 to 500 mPa · s. The solution viscosity (mPa · s) of polyamic acid, polyamic acid ester, and polyimide was 10% by weight with a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) of these polymers. Is a value measured at 25 ° C. using an E-type rotational viscometer.

  The polystyrene-equivalent weight average molecular weight (Mw) measured by polyamic acid, polyamic acid ester and polyimide gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Moreover, the molecular weight distribution (Mw / Mn) represented by the ratio between Mw and the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. By being in such a molecular weight range, it is possible to ensure good orientation and stability of the liquid crystal display element.

[Polyorganosiloxane]
The polyorganosiloxane according to the present invention can be obtained, for example, by hydrolyzing and condensing a hydrolyzable silane compound.

Examples of silane compounds used in the synthesis of polyorganosiloxane include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxy. Alkoxysilane compounds such as silane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane , 3-aminopropyltriethoxysilane, N- (3-cyclohexylamino) propyltrimethoxysilane, and other nitrogen / sulfur-containing alkoxysilane compounds ;
Epoxy group-containing silanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane Compound;
3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, vinyl Examples include unsaturated bond-containing alkoxysilane compounds such as trimethoxysilane, vinyltriethoxysilane, and p-styryltrimethoxysilane; trimethoxysilylpropyl succinic anhydride and the like. One of these hydrolyzable silane compounds can be used alone or in combination of two or more. Note that “(meth) acryloxy” means “acryloxy” and “methacryloxy”.

  The hydrolysis / condensation reaction can be carried out by reacting one or more of the above silane compounds with water, preferably in the presence of an appropriate catalyst and an organic solvent. In the hydrolysis / condensation reaction, the proportion of water used is preferably 0.5 to 100 mol, more preferably 1 to 30 mol, per 1 mol of the silane compound (total amount).

Examples of the catalyst used in the hydrolysis / condensation reaction include acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds and the like. The amount of catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, and should be set as appropriate. For example, it is preferably 0.01 to 3 times the total amount of the silane compound. More preferably, it is 0.05-1 times mole.
Examples of the organic solvent used in the above hydrolysis / condensation reaction include hydrocarbons, ketones, esters, ethers, alcohols and the like. Among these, it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The use ratio of the organic solvent is preferably 10 to 10,000 parts by weight, and more preferably 50 to 1,000 parts by weight with respect to a total of 100 parts by weight of the silane compounds used in the reaction.

  The hydrolysis / condensation reaction is preferably carried out by heating with, for example, an oil bath. In the hydrolysis / condensation reaction, the heating temperature is preferably 130 ° C. or lower, more preferably 40 to 100 ° C. The heating time is preferably 0.5 to 12 hours, and more preferably 1 to 8 hours. During heating, the mixture may be stirred or placed under reflux. Moreover, it is preferable to wash | clean the organic-solvent layer fractionated from the reaction liquid with water after completion | finish of reaction. In this washing, washing with water containing a small amount of salt (for example, an aqueous ammonium nitrate solution of about 0.2% by weight) is preferable in that the washing operation is facilitated. Washing is performed until the aqueous layer after washing becomes neutral, and then the organic solvent layer is dried with a desiccant such as anhydrous calcium sulfate or molecular sieve as necessary, and then the solvent is removed to remove the solvent. The polyorganosiloxane can be obtained. The method for synthesizing the polyorganosiloxane is not limited to the hydrolysis / condensation reaction described above, and may be performed by, for example, a method in which a hydrolyzable silane compound is reacted in the presence of oxalic acid and alcohol.

  In the condensation reaction, a polyorganosiloxane having an epoxy group in the side chain (hereinafter also referred to as “epoxy group-containing polysiloxane”) can be obtained by using an epoxy group-containing silane compound as at least a part of the raw material. it can. Further, the obtained epoxy group-containing polysiloxane may be further reacted with a carboxylic acid having a liquid crystal aligning group. By this reaction, a polyorganosiloxane having a liquid crystal alignment group in the side chain can be obtained. The reaction between the epoxy group-containing polysiloxane and the carboxylic acid can be carried out according to a known method. Or you may synthesize | combine the polyorganosiloxane which has a liquid crystal aligning group in a side chain by reaction which contains the hydrolysable silane compound which has a liquid crystal aligning group in a monomer.

  For the polyorganosiloxane according to the present invention, the polystyrene-reduced weight average molecular weight (Mw) measured by GPC is preferably in the range of 100 to 50,000, more preferably in the range of 200 to 10,000. . When the weight average molecular weight of the polysiloxane is in the above range, it is easy to handle when producing a liquid crystal alignment film, and the obtained liquid crystal alignment film has sufficient material strength and characteristics.

The liquid crystal aligning agent which concerns on this invention contains the polymer chosen from the group which consists of a polyamic acid, a polyimide, a polyamic acid ester, and a polyorganosiloxane as a polymer (A) individually by 1 type or in combination of 2 or more types. To do. Although the content aspect of the polymer (A) in a liquid crystal aligning agent can be suitably selected according to the use and environment to be used, the following [1]-[3] aspects etc. are mentioned, for example.
[1] An embodiment in which the polymer (A) is at least one selected from the group consisting of polyamic acid, polyimide and polyamic acid ester.
[2] An embodiment containing, as the polymer (A), at least one selected from the group consisting of polyamic acid, polyimide, and polyamic acid ester, and polyorganosiloxane.
[3] An embodiment in which the polymer (A) is a polyorganosiloxane.
Among these, the aspect [1] or [2] is preferable, and the aspect [1] is more preferable in terms of obtaining the effects of the present invention more suitably. In the case of the above [2], the total content of polyamic acid, polyimide and polyamic acid ester is preferably 5% by weight or more based on the total amount of the polymer (A) contained in the liquid crystal aligning agent, More preferably, the content is 10% by weight or more.

<Other ingredients>
The liquid crystal aligning agent which concerns on this invention may contain the other component as needed other than the said polymer (A). Other components that may be blended in the liquid crystal aligning agent include, for example, other polymers other than the polymer (A), compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy group-containing compound”). And a functional silane compound.

[Other polymers]
The above other polymers can be used for improving solution properties and electrical properties. Specific examples of such other polymers include polymers having a main skeleton of polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. it can.
When other polymers are blended in the liquid crystal aligning agent, the blending ratio is preferably 30 parts by weight or less with respect to a total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent. It is more preferable to set it as 20 weight part, and it is still more preferable to set it as 0.3-10 weight part.

[Epoxy group-containing compound]
The epoxy group-containing compound can be used to improve the adhesion and electrical properties with the substrate surface in the liquid crystal alignment film. Examples of such epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, N, N, N ′, N′-tetraglycidyl-m-xylylene diene Amine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diamy Diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, N, N-diglycidyl - may be mentioned as being preferred and cyclohexylamine. In addition, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can be used.
When adding these epoxy compounds to a liquid crystal aligning agent, it is preferable that the mixture ratio shall be 40 weight part or less with respect to a total of 100 weight part of the polymer contained in a liquid crystal aligning agent, 0.1-30 More preferred are parts by weight.

[Functional silane compounds]
The functional silane compound can be used for the purpose of improving the printability of the liquid crystal aligning agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3- Aminopropyltrimethoxysilane, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl -3,6- Methyl azananoate, N-benzyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycid And xylpropyltrimethoxysilane.
When these functional silane compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 2 parts by weight or less with respect to a total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent. It is more preferable to set it to -0.2 weight part.

  In addition to the above, as other components, additives that can be used for preparing a liquid crystal aligning agent can be used. Specific examples include compounds having at least one oxetanyl group in the molecule, antioxidants, surfactants, photosensitizers, and photopolymerizable compounds.

<Solvent>
The liquid crystal aligning agent which concerns on this invention is prepared as a liquid composition formed by disperse | distributing or melt | dissolving a polymer (A) and the other component mix | blended as needed in an organic solvent. In particular, the liquid crystal aligning agent according to the present invention contains 2-butoxy-1-propanol in an amount of 0.1 to 50% by weight based on the total amount of solvent. From the viewpoint of further enhancing the effect of improving the applicability to the substrate and the reliability of the liquid crystal display element, the content ratio of 2-butoxy-1-propanol may be 0.3 to 40% by weight based on the total amount of the solvent. More preferably, it is 0.5 to 35% by weight, more preferably 1 to 30% by weight.

  Examples of other solvents to be included in the liquid crystal aligning agent together with 2-butoxy-1-propanol include aprotic polar solvents, phenol solvents, alcohols (excluding 2-butoxy-1-propanol), ketones, esters, and ethers. And halogenated hydrocarbons and hydrocarbons. Among these, at least one selected from the group consisting of an aprotic polar solvent and a phenolic solvent (first group organic solvent), or at least one selected from the first group organic solvent, and an alcohol It is preferable to use a mixture with one or more selected from the group consisting of, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second group organic solvent) as the other solvent.

Specific examples of other solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4- Hydroxy-4-methyl-2-pentanone, 1-butoxy-2-propanol, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol Ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether Acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate , Propylene carbonate, diacetone alcohol, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dimethyl ether Ether, dipropylene glycol diethyl ether, dipropylene glycol methyl - propyl ether, and dipropylene glycol methyl ether acetate.
Particularly preferred as other solvent used in combination with 2-butoxy-1-propanol, ethylene glycol-n-butyl ether, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, 1-butoxy-2-propanol, N-methyl-2-pyrrolidone , N-ethyl-2-pyrrolidone, and γ-butyrolactone. In addition, the other solvent can use 1 type of these individually or in mixture of 2 or more types.

  The solid content concentration in the liquid crystal aligning agent (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. It is in the range of 1 to 10% by weight. That is, the liquid crystal aligning agent is applied to the substrate surface as will be described later, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that becomes a liquid crystal alignment film. At this time, when the solid content concentration is less than 1% by weight, the film thickness of the coating film becomes too small, and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, it is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive, and the viscosity of the liquid crystal aligning agent increases and the applicability decreases. There is a tendency.

  The particularly preferable range of the solid content concentration 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 solid content concentration (the ratio of the total weight of all components other than the solvent in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is in the range of 1.5 to 4.5% by weight. It is particularly preferred. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s. The temperature when preparing the liquid crystal aligning agent is preferably 10 to 50 ° C, more preferably 20 to 30 ° C.

[Liquid crystal alignment film and liquid crystal display element]
A liquid crystal alignment film can be manufactured by using the liquid crystal aligning agent described above. Moreover, the liquid crystal display element which concerns on this invention comprises the liquid crystal aligning film formed using the said liquid crystal aligning agent. The operation mode of the liquid crystal display element according to the present invention is not particularly limited. For example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB type, etc. It can be applied to various operation modes.

  The liquid crystal display element which concerns on this invention can be manufactured according to the process containing the following processes (1-1)-(1-3), for example. In the step (1-1), a substrate to be used is different depending on a desired operation mode. Step (1-2) and step (1-3) are common to each operation mode.

[Step (1-1): Formation of coating film]
First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-1A) When manufacturing a TN-type, STN-type, or VA-type liquid crystal display element, for example, first, a pair of two substrates on which patterned transparent conductive films are provided, and each transparent conductive film is formed. On the surface, the liquid crystal aligning agent prepared above is preferably applied by an offset printing method, a spin coating method, a roll coater method or an ink jet printing method. As the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. Can be used. In order to obtain a patterned transparent conductive film, for example, after forming a transparent conductive film without a pattern, a method of forming a pattern by photo-etching; a method of using a mask having a desired pattern when forming a transparent conductive film; And so on. When applying the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film, a functional silane compound or a functional titanium compound is formed on the surface of the substrate surface on which the coating film is formed. It is also possible to perform a pretreatment to apply the above in advance.

  After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-bake time is preferably 0.25 to 10 minutes, and more preferably 0.5 to 5 minutes. Then, a baking (post-baking) process is implemented for the purpose of removing a solvent completely and heat imidating the amic acid structure which exists in a polymer as needed. The firing temperature (post-bake temperature) at this time is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The post-bake time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The thickness of the film thus formed is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

  (1-1B) When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape, and an electrode are provided. A liquid crystal aligning agent is apply | coated to one surface of the counter substrate which is not formed, respectively, Then, each coating surface is heated, and a coating film is formed. Regarding the material used for the substrate and the transparent conductive film, the coating method, the heating conditions after coating, the patterning method for the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the coating film to be formed The same as (1-1A). As the metal film, for example, a film made of a metal such as chromium can be used.

  In both cases (1-1A) and (1-1B), after applying a liquid crystal aligning agent on the substrate, the organic solvent is removed to form a liquid crystal alignment film or a liquid crystal alignment film. The At this time, by further heating after the formation of the coating film, the dehydration ring-closing reaction of the polyamic acid, polyamic acid ester and polyimide blended in the liquid crystal aligning agent of the present invention may be advanced to obtain a more imidized coating film.

[Step (1-2): Orientation ability imparting treatment]
When manufacturing a TN type, STN type, IPS type, or FFS type liquid crystal display element, the process which provides liquid crystal aligning ability to the coating film formed at the said process (1-1) is implemented. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film. Examples of the alignment ability imparting treatment include a rubbing treatment in which a coating film is rubbed in a fixed direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton, and photo-alignment in which the coating film is irradiated with polarized or non-polarized radiation. Processing. On the other hand, when manufacturing a VA type liquid crystal display element, the coating film formed in the above step (1-1) can be used as it is as a liquid crystal alignment film. May be.

When the liquid crystal alignment ability is imparted to the coating film by the photo-alignment treatment, for example, ultraviolet rays and visible rays including light having a wavelength of 150 to 800 nm can be used as the radiation applied to the coating film. When the radiation is polarized light, it may be linearly polarized light or partially polarized light. When the radiation used is linearly polarized light or partially polarized light, irradiation may be performed from a direction perpendicular to the substrate surface, an oblique direction, or a combination thereof. When irradiating non-polarized radiation, the direction of irradiation is an oblique direction.
As a light source to be used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter or a diffraction grating. The radiation dose is preferably 100 to 50,000 J / m ² , more preferably 300 to 20,000 J / m ² . Moreover, you may perform light irradiation with respect to a coating film, heating a coating film, in order to improve the reactivity. The temperature at the time of heating is 30-250 degreeC normally, Preferably it is 40-200 degreeC, More preferably, it is 50-150 degreeC.

  In addition, the liquid crystal alignment film after the rubbing treatment is further subjected to a process for changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet rays or a surface of the liquid crystal alignment film. A resist film is formed on the part, and a rubbing process is performed in a direction different from the previous rubbing process, followed by a process of removing the resist film, so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region. . In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element. A liquid crystal alignment film suitable for a VA liquid crystal display element can also be suitably used for a PSA (Polymer sustained alignment) type liquid crystal display element.

[Step (1-3): Construction of liquid crystal cell]
Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and a liquid crystal cell is manufactured by disposing a liquid crystal between the two substrates disposed to face each other. In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example. The first method is a conventionally known method. First, two substrates are arranged opposite to each other through a gap (cell gap) so that the respective liquid crystal alignment films are opposed to each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the substrate surface and the sealant are bonded. A liquid crystal cell is manufactured by injecting and filling the liquid crystal into the cell gap partitioned by the step of sealing the injection hole. The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet light curable sealant is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystal is dropped at predetermined locations on the liquid crystal alignment film surface. After that, the other substrate is bonded so that the liquid crystal alignment films face each other and the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thereby manufacturing a liquid crystal cell. . Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase and then gradually cooled to room temperature. It is desirable to remove.

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, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl. Cyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, cubane liquid crystals, and the like can be used. Further, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, and cholesteryl carbonate; chiral agents such as those sold under the trade names “C-15” and “CB-15” (manufactured by Merck & Co., Inc.). A ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added and used.

  And the liquid crystal display element which concerns on this invention can be obtained by bonding a polarizing plate on the outer surface of a liquid crystal cell. As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called an “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned.

  The liquid crystal display device according to the present invention can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones. It can be used in various display devices such as various monitors, liquid crystal televisions, and information displays.

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

In the following examples, the imidization ratio of polyimide and the solution viscosity of the polymer solution were measured by the following methods.
[Imidation rate of polyimide]
The polyimide solution was poured into pure water, and the resulting precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidation ratio [%] was determined by the following mathematical formula (1).
Imidation ratio [%] = (1-A ¹ / A ² × α) × 100 (1)
(In Formula (1), A ¹ is a peak area derived from protons of NH groups appearing near a chemical shift of 10 ppm, A ² is a peak area derived from other protons, and α is a precursor of a polymer (polyamic acid). The number ratio of other protons to one proton of NH group in)
[Solution viscosity of polymer solution]
The solution viscosity [mPa · s] of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer for a solution prepared to a polymer concentration of 10% by weight using a predetermined solvent.

<Synthesis of polymer>
[Synthesis Example 1: Synthesis of polyimide (PI-1)]
100 mol parts of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride, 60 mol parts of p-phenylenediamine as diamine, and 20 mol parts of cholestanyloxy-2,4-diaminobenzene, It was dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 56 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a solution having a polyamic acid concentration of 7% by weight, and pyridine and acetic anhydride were each 2.0 times the total amount of tetracarboxylic dianhydride used. The mixture was added in moles, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new NMP (by this operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same applies hereinafter), whereby the imidation rate was about 85. A solution containing 26% by weight of polyimide (PI-1) was obtained. The reaction solution was then poured into a large excess of methanol to precipitate the reaction product. This precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain polyimide (PI-1).

[Synthesis Examples 2 and 3]
Polyimide (PI-2) in the same manner as in Synthesis Example 1 except that the types and amounts of tetracarboxylic dianhydride and diamine used, and the amounts of pyridine and acetic anhydride used for imidization were changed as shown in Table 1 below. , (PI-3) were synthesized respectively. The measurement results of the imidization ratio of the obtained polymer are shown in Table 1 below.

In Table 1, the numbers in parentheses of tetracarboxylic dianhydride and diamine represent the usage ratio [mole part] with respect to a total of 100 parts by mole of tetracarboxylic dianhydride used for the synthesis of the polymer. The numerical values of pyridine and acetic anhydride indicate the use ratio [fold mole] of each compound with respect to the total amount of tetracarboxylic dianhydride used. Abbreviations in Table 1 have the following meanings.
<Tetracarboxylic dianhydride>
t-1: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride t-2: 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-2 Anhydride t-3: 1,2,3,4-cyclobutanetetracarboxylic dianhydride t-4: Compound represented by the above formula (B-1-1) <Diamine>
d-1: p-phenylenediamine d-2: cholestanyloxy-2,4-diaminobenzene d-3: 3,5-diaminobenzoic acid d-4: represented by the above formula (E-1-4) Compound d-5: Compound represented by the above formula (D-2-6) d-6: Compound represented by the following formula (d-6)

[Synthesis Example 4: Synthesis of polyamic acid (PA-1)]
100 mol parts of the compound represented by the above formula (B-1-1) as tetracarboxylic dianhydride, 20 mol parts of the compound represented by the above formula (D-2-6) as diamine, and the above formula (d) −6) 80 mol part of the compound represented by is dissolved in a mixed solvent of NMP and γ-butyrolactone (γBL) (NMP: γBL = 10: 90 (weight ratio)) and reacted at 40 ° C. for 3 hours. A solution containing 10% by weight of polyamic acid (PA-1) was obtained. The solution viscosity measured by collecting a small amount of the obtained polyamic acid solution was 180 mPa · s. The polyamic acid solution was then poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain polyamic acid (PA-1).

[Example 1]
(1) Preparation of liquid crystal aligning agent As a polymer, NMP, butyl cellosolve (BC) and 2-butoxy-1-propanol (X) are added as solvents to the polyimide (PI-1) obtained in Synthesis Example 1 above, and a solvent composition is obtained. NMP: BC: (X) = 50: 20: 30 (weight ratio) and a solid content concentration of 6.5% by weight. A liquid crystal aligning agent (S1) was prepared by filtering this solution using a filter having a pore diameter of 1 μm.

(2) Evaluation of repelling After a silicon wafer having a diameter of 6 inches was immersed in a 0.1% by weight polydimethylsiloxane aqueous solution for 30 minutes, it was blown with air and dried at 100 ° C. for 30 minutes. The liquid crystal aligning agent (S1) was apply | coated to the surface of the obtained board | substrate with the liquid crystal aligning film printing machine (Nippon Photo Printing Co., Ltd., Angstromer type "S40L-532"). At this time, the coating property was evaluated by the number of repellants generated on the substrate surface. Here, when the number of repels is 0 to 1, the applicability is “excellent (◎)”, and when the number of repels is 2 to 5, the applicability is “good (◯)” and the number of repels. When the number was 6 to 10, the applicability was “possible (Δ)”, and when the number of cistern was 11 or more, the applicability was “bad (×)”. In this example, the number of repels was 6, and the applicability was “evaluated”.

(3) Manufacture of VA type liquid crystal cell The liquid crystal aligning agent (S1) prepared above is liquid crystal aligning film printer (Japanese photograph) on the transparent electrode surface of the glass substrate with a transparent electrode (thickness 1 mm) made of ITO film. Printing (manufactured by Printing Co., Ltd.), heating (pre-baking) for 1 minute on a hot plate at 80 ° C., and further heating (post-baking) for 60 minutes on a hot plate at 200 ° C. A coating film (liquid crystal alignment film) was formed. This operation was repeated to obtain a pair (two) of glass substrates having a liquid crystal alignment film on the transparent conductive film. Next, for one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and then the pair of substrates is aligned with the liquid crystal alignment film surface. The adhesives were cured by overlapping and pressing so that they face each other. Next, a nematic liquid crystal (MLC-6608, manufactured by Merck & Co., Inc.) was filled between the pair of substrates through the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to produce a VA liquid crystal cell. .

(4) Evaluation of reliability The reliability of the liquid crystal display element was evaluated using the liquid crystal cell manufactured above. Evaluation was performed as follows. First, a voltage of 5 V was applied to the liquid crystal cell with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR1) after 167 milliseconds from the release of application was measured. Next, the liquid crystal cell was allowed to stand in an 80 ° C. oven under LED lamp irradiation for 200 hours, and then allowed to stand at room temperature and naturally cooled to room temperature. After cooling, a voltage of 5 V was applied to the liquid crystal cell with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR2) 167 milliseconds after the application release was measured. The measuring device used was “VHR-1” manufactured by Toyo Corporation. The change rate (ΔVHR) of VHR at this time was calculated by the following mathematical formula (2), and the reliability was evaluated by ΔVHR.
ΔVHR [%] = (VHR1−VHR2) / (VHR1) × 100 (2)
In the evaluation, when ΔVHR was less than 1%, the reliability was “excellent (◎)”, and when it was 1% or more and less than 2%, the reliability was “good” (◯), and the reliability was 2% or more and less than 3%. The reliability was “possible (Δ)” and the reliability was 3% or more, and the reliability was “bad” (x). As a result, in Example 1, ΔVHR = 2.5 [%], and the reliability was “possible”.

[Example 2 and Comparative Example 1]
A liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the composition of the liquid crystal aligning agent was changed as shown in Table 2 below. Further, using each of the prepared liquid crystal aligning agents, repelling evaluation, production of a VA type liquid crystal cell and reliability evaluation were performed in the same manner as in Example 1. The evaluation results are shown in Table 3 below.

In Table 2, the numerical value in the column of the solvent ratio represents the usage ratio [parts by weight] of each solvent with respect to 100 parts by weight in total of the solvents used for preparing the liquid crystal aligning agent. Abbreviations in Table 2 have the following meanings.
<Solvent>
NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve NEP: N-ethyl-2-pyrrolidone DPM: Dipropylene glycol monomethyl ether DEDG: Diethylene glycol diethyl ether PG: 1-butoxy-2-propanol (X): 2-butoxy- 1-propanol

[Example 3]
(1) Preparation of liquid crystal aligning agent A liquid crystal aligning agent (S3) was prepared in the same manner as in Example 1 except that the composition of the liquid crystal aligning agent was changed as shown in Table 2 above.
(2) Evaluation of repelling As in Example 1, except that the liquid crystal aligning agent (S3) was used instead of the liquid crystal aligning agent (S1) and the coating method of the liquid crystal aligning agent was changed from the printing method to the ink jet method. The repellency was evaluated. The apparatus used was an ink jet coating apparatus (manufactured by Shibaura Mechatronics Co., Ltd.), and the coating conditions were two reciprocating coatings (four coatings) with a head number of 64 and a dispensing amount of 0.2 g / head · second. As a result, in this example, the number of repels was 0, which was an evaluation of “excellent”.
(3) Production of VA liquid crystal cell and evaluation of reliability The point that the liquid crystal aligning agent (S3) was used instead of the liquid crystal aligning agent (S1), and the coating method of the liquid crystal aligning agent was changed from the printing method to the ink jet method. Except for the points, a VA liquid crystal cell was produced in the same manner as in Example 1, and reliability was evaluated using the obtained liquid crystal cell. As a result, in this example, ΔVHR = 0.6 [%], and the reliability was evaluated as “excellent” (see Table 3).

[Example 4]
(1) Preparation of liquid crystal aligning agent A liquid crystal aligning agent (S4) was prepared in the same manner as in Example 1 except that the composition of the liquid crystal aligning agent was changed as shown in Table 2 above.
(2) Evaluation of repelling Repelling evaluation was performed in the same manner as in Example 3 except that the liquid crystal aligning agent (S4) was used instead of the liquid crystal aligning agent (S3). As a result, in this example, the number of repels was 3, which was evaluated as “good”.
(3) Manufacture of IPS / FFS type liquid crystal cell using photo-alignment method With liquid crystal aligning agent (S4) prepared above, with transparent electrode made of ITO film using inkjet coating device (manufactured by Shibaura Mechatronics) It apply | coated to the transparent electrode surface of a glass substrate. The application conditions were the same as those in “(2) Evaluation of repelling”. Subsequently, the solvent was removed by heating (prebaking) on an 80 ° C. hot plate for 1 minute. Then, using a Hg-Xe lamp, after irradiating polarized ultraviolet rays containing a 254 nm emission line from the substrate normal at a dose of 700 mJ / cm ² , heating (post-baking) on a hot plate at 200 ° C. for 10 minutes. Thus, a coating film having an average film thickness of 800 mm and provided with a liquid crystal alignment film was formed. The above operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
Next, for one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and then the polarizing surface of polarized ultraviolet light is applied to the substrate. The adhesive was cured by stacking and pressing the pair of substrates so that the liquid crystal alignment film faces each other so that the projected directions were parallel. Next, a nematic liquid crystal (MLC-6221, manufactured by Merck & Co., Inc.) is filled between a pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, thereby obtaining an IPS / FFS type liquid crystal. A cell was manufactured.

(4) Evaluation of reliability Using the IPS / FFS type liquid crystal cell manufactured above, the reliability was evaluated by the same method as in Example 1. As a result, ΔVHR = 0.8 [%], and the reliability was The evaluation was “Excellent”.

  As shown in Table 3, in Examples 1 to 4, the applicability and reliability were evaluated as “excellent” to “possible” regardless of the application method. In addition, the coating property can be further improved by using a polymer containing a carboxyl group-containing diamine as a raw material together with a specific solvent (2-butoxy-1-propanol), and the reliability includes a nitrogen-containing structure together with the specific solvent. It has been found that further improvement can be achieved by using a polymer containing a diamine having a diamine as a raw material. On the other hand, in Comparative Example 1, the applicability was “bad” and the reliability was “good”, and Examples 1 to 4 were superior.

Claims (5)

At least one polymer selected from a polyamic acid and polyimide by Li Cheng group and (A), containing a solvent, a,
The said solvent is a liquid crystal aligning agent which contains 0.1-50 weight% of 2-butoxy-1-propanol with respect to the total amount of solvents.   The liquid crystal aligning agent of Claim 1 containing the polymer which has at least 1 type of nitrogen-containing structure chosen from the group which consists of a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group as said polymer (A). . Wherein as the polymer (A), comprising a polymer obtained by using a diamine component containing a diamine compound having a mosquito carboxyl group, the liquid crystal alignment agent according to claim 1 or 2.   The liquid crystal aligning film formed using the liquid crystal aligning agent as described in any one of Claims 1-3.   A liquid crystal display device comprising the liquid crystal alignment film according to claim 4.