JP2014021447A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal aligning agent that can form a liquid crystal display element having high light resistance and has an excellent coating property and high reworkability.SOLUTION: The liquid crystal aligning agent contains [A] a compound represented by the following formula (1), and [B] a polymer. In the following formula (1), Rrepresents a hydrogen atom, a 6-20C monovalent aromatic hydrocarbon group, a 4-20C monovalent heterocyclic group, or a group obtained by substituting a part or all of hydrogen atoms included in the aromatic hydrocarbon group and heterocyclic group with a substituent. Rrepresents a 1-12C alkyl group or a 1-12C alkoxy group. Rand Reach represent a hydrogen atom, a halogen atom or a 1-20C alkyl group. [B] polymer is preferably at least one kind selected from the group consisting of polyamic acid, polyimide and poly siloxane, and more preferably at least one kind selected from the group consisting of polyamic acid and polyimide.

Description

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

  As the liquid crystal display element, various driving methods typified by TN type, STN type, VA type and the like have been developed. These liquid crystal display elements have a liquid crystal alignment film as one of main components. This liquid crystal alignment film plays a role of aligning the direction of liquid crystal molecules in a state suitable for the operation mode in the liquid crystal display element. As a material for such a liquid crystal alignment film, polyimide or the like is generally used from the viewpoint of heat resistance, mechanical strength, affinity with liquid crystal, and the like (Japanese Patent Laid-Open Nos. 9-197411 and 2003). -149648 and JP-A-2003-107486).

  In recent years, liquid crystal display elements have been required to improve display quality, and the liquid crystal alignment film has been improved along with improvements in driving methods and element structures. In particular, with the increasing use of smartphones and information displays, the opportunity for use in harsh environments has increased, and even when exposed to light stress during long-term operation, electrical characteristics can be maintained well. There is a demand for a liquid crystal alignment film having excellent light resistance.

  In response to such demands, a technique for increasing the imidization ratio of polyimide used for the liquid crystal alignment film has been proposed (see Japanese Patent Application Laid-Open Nos. 2010-2501 and 2011-28223). However, under the present situation where further improvement in display quality is required, it cannot be said that the above-described requirements are sufficiently satisfied by the conventional technology. In addition, in the manufacturing process, high applicability to the substrate of the liquid crystal aligning agent used for forming the liquid crystal alignment film and high reworkability capable of correcting defective products are also required.

JP-A-9-197411 JP 2003-149648 A JP 2003-107486 A JP 2010-2501 A JP 2011-28223 A

  The present invention has been made based on the circumstances as described above, and an object of the present invention is to provide a liquid crystal aligning agent capable of forming a liquid crystal display element having excellent light resistance and having high coating property and reworkability. Is to provide.

（式（１）中、Ｒ^１は、水素原子、炭素数６〜２０の１価の芳香族炭化水素基、炭素数４〜２０の１価の複素環基、又はこれらの芳香族炭化水素基及び複素環基の有する水素原子の一部若しくは全部が炭素数１〜２０のアルキル基、炭素数１〜１２のアルコキシ基、アミノ基、モノアルキルアミノ基、ジアルキルアミノ基、ニトロソ基、メルカプト基、スルフィド基、シリル基、シラノール基、スルフィノ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、ケト基、エステル基、トリフルオロメチル基、ヒドロキシ基、ハロゲン原子、シアノ基、ニトロ基、カルボキシ基若しくはスルホ基で置換された基である。Ｒ^２は、炭素数１〜１２のアルキル基又は炭素数１〜１２のアルコキシ基である。Ｒ^３及びＲ^４は、それぞれ独立して、水素原子、ハロゲン原子又は炭素数１〜２０のアルキル基である。ｍは、０〜２の整数である。ｍが２の場合、２つのＲ^２は、同一でも異なっていてもよい。ｎは、１又は２である。ｎが２の場合、２つのＲ^３は、同一でも異なっていてもよい。ｒは、０〜１２の整数である。ｒが２以上の場合、複数のＲ^４は、同一でも異なっていてもよい。） The invention made to solve the above problems is
[A] A liquid crystal aligning agent containing a compound represented by the following formula (1) (hereinafter also referred to as “[A] compound”) and [B] a polymer.

(In the formula (1), R ¹ is a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a monovalent heterocyclic group having 4 to 20 carbon atoms, or an aromatic hydrocarbon group thereof. And some or all of the hydrogen atoms of the heterocyclic group are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, amino groups, monoalkylamino groups, dialkylamino groups, nitroso groups, mercapto groups, Sulfide group, silyl group, silanol group, sulfino group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, keto group, ester group, trifluoromethyl group, hydroxy group, halogen atom, cyano group, nitro group, R ² is a group substituted with a carboxy group or a sulfo group, R ² is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms R ³ and R ⁴ Are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms, m is an integer of 0 to 2. When m is 2, two R ^{2 s} are the same or different. N is 1 or 2. When n is 2, two R ^{3 s} may be the same or different, r is an integer of 0 to 12. r is 2 or more In this case, the plurality of R ⁴ may be the same or different.)

  Moreover, another invention made | formed in order to solve the said subject is the liquid crystal aligning film formed from the said liquid crystal aligning agent.

  Furthermore, another invention made to solve the above problems is a liquid crystal display element including the liquid crystal alignment film.

  The present invention can provide a liquid crystal aligning agent that can form a liquid crystal display element having excellent light resistance and has high coating properties and reworkability. Therefore, the liquid crystal aligning agent, the liquid crystal aligning film formed from the liquid crystal aligning agent, and the liquid crystal display element including the liquid crystal aligning film are used in an electronic device capable of maintaining a high display quality over a long period of time and a manufacturing process thereof. It can be preferably used.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention contains a [A] compound and a [B] polymer. Moreover, the said liquid crystal aligning agent may contain a [C] solvent as a suitable component. Furthermore, the liquid crystal aligning agent may contain other optional components as long as the effects of the present invention are not impaired. Hereinafter, each component will be described in detail.

[[A] Compound]
[A] A compound is a compound denoted by the above-mentioned formula (1). Since the liquid crystal aligning agent contains the [A] compound having the specific structure, the liquid crystal display element formed from the liquid crystal aligning agent has high coatability and reworkability while maintaining excellent light resistance. .

In the above formula (1), R ¹ is a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a monovalent heterocyclic group having 4 to 20 carbon atoms, or an aromatic hydrocarbon group thereof. And some or all of the hydrogen atoms of the heterocyclic group are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, amino groups, monoalkylamino groups, dialkylamino groups, nitroso groups, mercapto groups, Sulfide group, silyl group, silanol group, sulfino group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, keto group, ester group, trifluoromethyl group, hydroxy group, halogen atom, cyano group, nitro group, It is a group substituted with a carboxy group or a sulfo group. R ² is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms. m is an integer of 0-2. When m is 2, two R ² may be the same or different. n is 1 or 2. When n is 2, two R ³ may be the same or different. r is an integer of 0-12. When r is 2 or more, the plurality of R ⁴ may be the same or different.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ^1, for example, a phenyl group, a naphthyl group, an anthryl group and the like.

Examples of the monovalent heterocyclic group having 4 to 20 carbon atoms represented by R ¹ include a pyridyl group, a pyrimidyl group, a furyl group, a chenyl group, a tetrahydrofuryl group, a dioxolanyl group, and a benzoxazol-2-yl group. , Tetrahydropyranyl group, pyrrolidyl group, imidazolicyl group, pyrazolysyl group, thiazolysyl group, inchazolysyl group, oxazolyl group, isoxazolyl group, piperidyl group, piperazyl group, morpholinyl group and the like. Among these, a nitrogen-containing heterocyclic group is preferable, and a pyridyl group is more preferable.

  Examples of the alkyl group having 1 to 20 carbon atoms as a substituent that may substitute part or all of the hydrogen atoms of the aromatic hydrocarbon group and heterocyclic group include a methyl group, an ethyl group, and n- Examples include propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-dodecyl group, n-pentadecyl group, and n-nonadecyl group. It is done.

  Examples of the alkoxy group having 1 to 12 carbon atoms as the substituent include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a butoxy group, and a pentyloxy group.

  Examples of the monoalkylamino group as the substituent include a methylamino group, an ethylamino group, an n-propylamino group, an n-butylamino group, and an n-hexylamino group.

  Examples of the dialkylamino group as the substituent include a dimethylamino group, a diethylamino group, a di-n-propylamino group, a di-n-butylamino group, and an N-methyl-N-cyclohexylamino group.

  Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R ¹ is preferably a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms or a monovalent heterocyclic group having 4 to 20 carbon atoms, more preferably a monovalent heterocyclic group having 4 to 20 carbon atoms. A nitrogen-containing heterocyclic group is more preferable, and a pyridyl group is particularly preferable.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² include those having 1 to 12 carbon atoms among the alkyl groups exemplified as the substituent for R ¹ . Among these, a methyl group, an ethyl group, an n-propyl group, and an i-propyl group are preferable, and a methyl group is more preferable.

Examples of the alkoxy group having 1 to 12 carbon atoms represented by R ² include the same groups as the alkoxy group having 1 to 12 carbon atoms exemplified as the substituent for R ¹ .

R ² is preferably an alkyl group having 1 to 12 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, and even more preferably a methyl group.

Examples of the halogen atom represented by R ³ and R ⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom is preferable.

Examples of the alkyl group having 1 to 20 carbon atoms represented by R ³ and R ⁴ include the same groups as those exemplified as the alkyl group having 1 to 20 carbon atoms as the substituent for R ^1. It is done. Among these, a C1-C6 alkyl group is preferable and a methyl group and an ethyl group are more preferable.

As said R < ³ > and R < ⁴ >, a hydrogen atom and a C1-C20 alkyl group are preferable, a hydrogen atom, a methyl group, and an ethyl group are more preferable, and a hydrogen atom is further more preferable.

  As said m, 0 or 1 is preferable and 0 is more preferable.

  As said n, 2 is preferable.

  As said r, 0-3 are preferable and 0 or 1 is more preferable.

  [A] The compound represented by the following formula is preferred as the compound.

  [A] As content of a compound, 0.01 mass%-50 mass% are preferable with respect to the total solid of the said liquid crystal aligning agent, 0.1 mass%-40 mass% are more preferable, 0.5 The mass% to 30 mass% is more preferable, and 1 mass% to 20 mass% is particularly preferable. [A] By making content of a compound into the said range, applicability | paintability can be improved effectively.

<[A] Compound Synthesis Method>
The compound [A] can be synthesized by combining known techniques. For example, a method for synthesizing the [A] compound represented by the above formula (1-1) includes a method of reacting 3,4-dihydrocoumarin with 3- (aminomethyl) pyridine. Examples of the method for synthesizing the [A] compound represented by the above formula (1-3) include a method of reacting 3,4-dihydrocoumarin with 4-aminopyridine. [A] compounds other than these can also be synthesized according to the above procedure or by changing a part of the above procedure.

<[B] polymer>
[B] The polymer is not particularly limited as long as it is a polymer, but it is preferably at least one selected from the group consisting of polyamic acid, polyimide and polysiloxane, and selected from the group consisting of polyamic acid and polyimide. More preferably, it is at least one kind. When the liquid crystal aligning agent contains the [B] polymer, the liquid crystal aligning film formed from the liquid crystal aligning agent can obtain good liquid crystal alignment by rubbing. Hereinafter, polyamic acid, polyimide, and polysiloxane will be described in detail.

[Polyamic acid]
A polyamic acid is a polymer having an amic acid structure. You may use the polyamic acid contained in the liquid crystal aligning agent of this invention individually or in combination of 2 or more types.

  The polyamic acid can be obtained by reacting tetracarboxylic dianhydride and diamine. In addition, you may use these tetracarboxylic dianhydride and diamine individually or in combination of 2 or more types, respectively.

  Examples of tetracarboxylic dianhydrides used for synthesizing this polyamic acid include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, and the like. Can be mentioned.

  Examples of the aliphatic tetracarboxylic dianhydride include butanetetracarboxylic dianhydride.

Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic 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-dicar Acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] Examples include octane-2,4,6,8-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone and the like.

  Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride.

  In addition to the above tetracarboxylic dianhydrides, the tetracarboxylic dianhydrides described in Japanese Patent Application No. 2010-97188 can be exemplified.

  Among these, the tetracarboxylic dianhydride used for synthesizing the polyamic acid preferably includes an alicyclic tetracarboxylic dianhydride, and 2,3,5-tricarboxycyclopentylacetic acid dihydrate. Anhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, , 3,3a, 4,5,9b-Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 2, , 4,6,8-tetracarboxybicyclo [3.3.0] octane-2,4,6,8-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride More preferably, 2, 3, - tricarboxy cyclopentyl acetic dianhydride, those comprising 2,4,6,8-tetracarboxylic [3.3.0] octane-2,4,6,8 dianhydride more preferred. In particular, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2,4,6,8-dianhydride What contains 10 mol% or more with respect to tetracarboxylic dianhydride is preferable, and what contains 20 mol%-100 mol% is more preferable.

  Examples of the diamine used for synthesizing the polyamic acid include alicyclic diamine, aromatic diamine, and diaminoorganosiloxane.

  Examples of the aliphatic diamine include 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and the like.

  Examples of the alicyclic diamine include 1,4-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane, and the like.

  Examples of the aromatic diamine include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diamino. Biphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 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) hexa Fluoropropane, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-fluoro Nylenediisopropylidene) 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-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diamino Carbazole, N, N′-bis (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethylbenzidine, 1,4-bis- (4-aminophenyl) Piperazine, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, Cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate Lanostaneyl 3,5-diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4′-trifluoromethoxybenzoyloxy) Cyclohexyl-3,5-diaminobenzoate, 4- (4′-trifluoromethylbenzoyloxy) Rohexyl-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-aminobenzylamine, compounds represented by the following formula (2), and the like.

In the above formula (2), ^{X I} is a methylene group, an alkylene group having a carbon number of 2 or 3, * - O -, * - COO-, or * -OCO- is. * Indicates a binding site with a diaminophenyl group. a is 0 or 1. b is an integer of 0-2. c is an integer of 1-20.

In the above formula (2), ^{X I} is a methylene group, an alkylene group having 2 or 3 carbon atoms, * - O -, * - COO- is preferred. Two amino groups in diamino phenyl group, 2,4-position or 3,5-position is preferred for ^{X I.} It is preferable that a and b are not 0 at the same time. As the _-C c _{H 2c + 1} in the above formula (2), for example, a methyl group, an ethyl group, n- propyl group, n- butyl group, n- pentyl group, n- hexyl, n- heptyl radical, 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-octadecyl group, n -Nonadecyl group, n-eicosyl group, etc. are mentioned.

  Examples of the aromatic diamine represented by the above formula (2) include compounds represented by the following formulas (2-1) to (2-3).

  Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and diaminoorganosiloxane described in JP-A No. 2010-97188.

  The diamine is preferably an aromatic diamine, more preferably cholestanyl 3,5-diaminobenzoate, cholestanyloxy-2,4-diaminobenzene, p-phenylenediamine, or 3,5-diaminobenzoic acid. Moreover, as said diamine, it is preferable to contain 30 mol% or more of aromatic diamine with respect to all the diamine, It is more preferable to contain 50 mol% or more, It is further more preferable to contain 80 mol% or more.

  Moreover, as a diamine used when synthesizing a polyamic acid in a VA type alignment film, among the above diamines, dodecanoxy-2,4-diaminobenzene, tetradecanoxy-2,4-diaminobenzene, pentadecanoxy- 2,4-diaminobenzene, hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, dodecanoxy-2,5-diaminobenzene, tetradecanoxy-2,5-diaminobenzene, pentadecanoxy-2,5-diamino Benzene, hexadecanoxy-2,5-diaminobenzene, octadecanoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy -2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, 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 and the above formula (2) The diamine is preferably contained in an amount of 5 mol% or more, more preferably 10 mol% or more, based on the total diamine.

<Method for synthesizing polyamic acid>
The polyamic acid can be synthesized by reacting tetracarboxylic dianhydride and diamine. As said tetracarboxylic dianhydride and diamine, what was demonstrated by the term of the said [polyamic acid] etc. can be used, for example. The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 equivalent to the acid anhydride group of the tetracarboxylic dianhydride relative to 1 equivalent of the amino group of the diamine. A ratio of 2 equivalents is preferable, and a ratio of 0.3 equivalents to 1.2 equivalents is more preferable.

  The synthesis of the polyamic acid is preferably performed in an organic solvent. The reaction temperature is preferably −20 ° C. to 150 ° C., more preferably 0 ° C. to 100 ° C. The reaction time is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 12 hours.

  Examples of the organic solvent used in the synthesis of polyamic acid include an aprotic polar solvent, a phenol solvent, an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, a hydrocarbon solvent, and the like.

Examples of the aprotic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like. Can be mentioned.
Examples of the phenol solvent include m-cresol, xylenol, and halogenated phenol.
Examples of the alcohol solvent include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.
Examples of the ester solvent include ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and diethyl malonate.
Examples of the ether solvent 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. Examples include 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, and tetrahydrofuran.
Examples of the hydrocarbon solvent include hexane, heptane, octane, benzene, toluene, xylene, isoamylpropionate, isoamylisobutyrate, diisopentyl ether, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane. , Trichloroethane, chlorobenzene, o-dichlorobenzene and the like.

  Among these organic solvents, at least one organic solvent selected from the group consisting of an aprotic polar solvent and a phenolic solvent (hereinafter, also referred to as “first group organic solvent”), or the organic solvent And at least one organic solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, ether solvents and hydrocarbon solvents (hereinafter also referred to as “second group organic solvents”). A mixture is preferred. In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by mass or less, more preferably 40% by mass or less, and more preferably 30% by mass with respect to the total mass of the first and second group organic solvents. The following is more preferable.

  As the usage-amount (a) of the said organic solvent, the total mass (b) of tetracarboxylic dianhydride and diamine will be 0.1 mass%-50 mass% with respect to the total mass (a + b) of a reaction solution. It is preferable to use an amount.

  In the synthesis of polyamic acid, an appropriate molecular weight regulator may be added to tetracarboxylic dianhydride and diamine to synthesize a terminal-modified polymer. By using such a terminal-modified polymer, the coating property of the liquid crystal aligning agent can be further improved without impairing the effects of the present invention.

  Examples of the molecular weight regulator include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. These molecular weight regulators may be used alone or in combination of two or more.

Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, Examples include n-hexadecyl succinic anhydride.
Examples of the monoamine compound include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine.
Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

  As a usage-amount of a molecular weight regulator, 20 mass parts or less are preferable with respect to a total of 100 mass parts of tetracarboxylic dianhydride and diamine to be used, and 10 mass parts or less are more preferable.

  The reaction solution containing the polyamic acid obtained as described above may be used for the preparation of the liquid crystal aligning agent as it is, and the polyamic acid contained in the reaction solution is isolated and used for the preparation of the liquid crystal aligning agent. Alternatively, the isolated polyamic acid may be purified and used for the preparation of the liquid crystal aligning agent. When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or the polyamic acid contained in the reaction solution may be isolated and subjected to dehydration and cyclization reaction. The released polyamic acid may be purified and subjected to a dehydration ring closure reaction. Isolation and purification of the polyamic acid can be performed according to known methods.

[Polyimide]
Polyimide is a polymer having an imide ring structure. You may use the polyimide contained in the liquid crystal aligning agent of this invention individually or in combination of 2 or more types.

  The polyimide can be obtained by dehydrating and ring-closing the polyamic acid synthesized as described above to imidize.

  This polyimide may be a completely imidized product obtained by dehydrating and cyclizing all of the amic acid structure that the polyamic acid that is a precursor thereof has, and only a part of the amic acid structure is dehydrated and cyclized. It may be a partially imidized product in which an imide ring structure coexists. The imidation ratio of polyimide is preferably 30% or more, more preferably 40% to 99%, and still more preferably 50% 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.

<Polyimide synthesis method>
The polyamic acid dehydration ring closure method in the synthesis of polyimide includes (1) a method of heating the polyamic acid, (2) dissolving the polyamic acid in an organic solvent, and adding a dehydrating agent and a dehydration ring closure catalyst to the resulting solution. The method of heating as necessary is preferable, and the method of (2) above is more preferable.

  In the method (2), examples of the dehydrating agent include acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. As the usage-amount of the said dehydrating agent, 0.01-20 mol is preferable with respect to 1 mol of the amic acid structure of a polyamic acid. Examples of the dehydration ring closure catalyst include tertiary amines such as pyridine, collidine, lutidine, and triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 mol to 10 mol with respect to 1 mol of the dehydrating agent used.

  Examples of the organic solvent used in the dehydration ring-closing reaction include the same organic solvents as those exemplified as the organic solvent used in the synthesis of polyamic acid. The reaction temperature for the dehydration ring closure reaction is preferably 0 ° C to 180 ° C, more preferably 10 ° C to 150 ° C. The reaction time is preferably 1.0 hour to 120 hours, more preferably 2.0 hours to 30 hours.

  The reaction solution containing the polyimide obtained as described above may be directly used for the preparation of the liquid crystal aligning agent, or may be used for the preparation of the liquid crystal aligning agent by removing the dehydrating agent and the dehydrating ring-closing catalyst from the reaction solution. The polyimide may be isolated and used for the preparation of the liquid crystal aligning agent, or the isolated polyimide may be purified and used for the preparation of the liquid crystal aligning agent. Isolation and purification of the polyimide can be performed according to known methods.

[Polysiloxane]
Polysiloxane is a polymer having a siloxane bond. This polysiloxane is preferably a hydrolysis condensate of a silane compound.

  Examples of the silane compound include tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, trichlorosilane, and trichlorosilane. Methoxysilane, triethoxysilane, tri-n-propoxysilane, tri-i-propoxysilane, tri-n-butoxysilane, tri-sec-butoxysilane, fluorotrichlorosilane, fluorotrimethoxysilane, fluorotriethoxysilane, fluoro Tri-n-propoxysilane, fluorotri-i-propoxysilane, fluorotri-n-butoxysilane, fluorotri-sec-butoxysilane, methyltrichlorosilane, methyltrimethoxysilane, methyl Triethoxysilane, methyltri-n-propoxysilane, methyltri-i-propoxysilane, methyltri-n-butoxysilane, methyltri-sec-butoxysilane, 2- (trifluoromethyl) ethyltrichlorosilane, 2- (trifluoromethyl) Ethyltrimethoxysilane, 2- (trifluoromethyl) ethyltriethoxysilane, 2- (trifluoromethyl) ethyltri-n-propoxysilane, 2- (trifluoromethyl) ethyltri-i-propoxysilane, 2- (trifluoro Methyl) ethyltri-n-butoxysilane, 2- (trifluoromethyl) ethyltri-sec-butoxysilane, 2- (perfluoro-n-hexyl) ethyltrichlorosilane, 2- (perfluoro-n-hexyl) ethyltrimethoxy Syrah 2- (perfluoro-n-hexyl) ethyltriethoxysilane, 2- (perfluoro-n-hexyl) ethyltri-n-propoxysilane, 2- (perfluoro-n-hexyl) ethyltri-i-propoxysilane, 2- (perfluoro-n-hexyl) ethyltri-n-butoxysilane, 2- (perfluoro-n-hexyl) ethyltri-sec-butoxysilane, 2- (perfluoro-n-octyl) ethyltrichlorosilane, 2- (Perfluoro-n-octyl) ethyltrimethoxysilane, 2- (perfluoro-n-octyl) ethyltriethoxysilane, 2- (perfluoro-n-octyl) ethyltri-n-propoxysilane, 2- (perfluoro -N-octyl) ethyltri-i-propoxysilane, 2- (perfluoro -N-octyl) ethyltri-n-butoxysilane, 2- (perfluoro-n-octyl) ethyltri-sec-butoxysilane, hydroxymethyltrichlorosilane, hydroxymethyltrimethoxysilane, hydroxyethyltrimethoxysilane, hydroxymethyltri- n-propoxysilane, hydroxymethyltri-i-propoxysilane, hydroxymethyltri-n-butoxysilane, hydroxymethyltri-sec-butoxysilane, 3- (meth) acryloxypropyltrichlorosilane, 3- (meth) acryloxy Propyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyltri-n-propoxysilane, 3- (meth) acryloxypropyltri-i-propoxy Lan, 3- (meth) acryloxypropyltri-n-butoxysilane, 3- (meth) acryloxypropyltri-sec-butoxysilane, 3-mercaptopropyltrichlorosilane, 3-mercaptopropyltrimethoxysilane, 3-mercapto Propyltriethoxysilane, 3-mercaptopropyltri-n-propoxysilane, 3-mercaptopropyltri-i-propoxysilane, 3-mercaptopropyltri-n-butoxysilane, 3-mercaptopropyltri-sec-butoxysilane, mercapto Methyltrimethoxysilane, mercaptomethyltriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltri-i-propoxysilane Vinyltri-n-butoxysilane, vinyltri-sec-butoxysilane, allyltrichlorosilane, allyltrimethoxysilane, allyltriethoxysilane, allyltri-n-propoxysilane, allyltri-i-propoxysilane, allyltri-n-butoxysilane, allyltri -Sec-butoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-i-propoxysilane, phenyltri-n-butoxysilane, phenyltri-sec-butoxy Silane, methyldichlorosilane, methyldimethoxysilane, methyldiethoxysilane, methyldi-n-propoxysilane, methyldi-i-propoxysilane, methyldi-n-butoxysila Methyldi-sec-butoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldi-i-propoxysilane, dimethyldi-n-butoxysilane, dimethyldi-sec-butoxysilane, (Methyl) [2- (perfluoro-n-octyl) ethyl] dichlorosilane, (methyl) [2- (perfluoro-n-octyl) ethyl] dimethoxysilane, (methyl) [2- (perfluoro-n- Octyl) ethyl] dimethoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] di-n-propoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] di-i -Propoxysilane, (methyl) [2- (perfluoro-n-octyl L) ethyl] di-n-butoxysilane, (methyl) [2- (perfluoro-n-octyl) ethyl] di-sec-butoxysilane, (methyl) (3-mercaptopropyl) dichlorosilane, (methyl) ( 3-mercaptopropyl) dimethoxysilane, (methyl) (3-mercaptopropyl) diethoxysilane, (methyl) (3-mercaptopropyl) di-n-propoxysilane, (methyl) (3-mercaptopropyl) di-i- Propoxysilane, (methyl) (3-mercaptopropyl) di-n-butoxysilane, (methyl) (3-mercaptopropyl) di-sec-butoxysilane, (methyl) (vinyl) dichlorosilane, (methyl) (vinyl) Dimethoxysilane, (methyl) (vinyl) diethoxysilane, (methyl) (vinyl) di-n Propoxysilane, (methyl) (vinyl) di-i-propoxysilane, (methyl) (vinyl) di-n-butoxysilane, (methyl) (vinyl) di-sec-butoxysilane, divinyldichlorosilane, divinyldimethoxysilane, Divinyldiethoxysilane, divinyldi-n-propoxysilane, divinyldi-i-propoxysilane, divinyldi-n-butoxysilane, divinyldi-sec-butoxysilane, diphenyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n -Propoxysilane, diphenyldi-i-propoxysilane, diphenyldi-n-butoxysilane, diphenyldi-sec-butoxysilane, chlorodimethylsilane, methoxydimethylsilane, ethoxydimethylsilane, Rolotrimethylsilane, bromotrimethylsilane, iodotrimethylsilane, methoxytrimethylsilane, ethoxytrimethylsilane, n-propoxytrimethylsilane, i-propoxytrimethylsilane, n-butoxytrimethylsilane, sec-butoxytrimethylsilane, t-butoxytrimethylsilane, (Chloro) (vinyl) dimethylsilane, (methoxy) (vinyl) dimethylsilane, (ethoxy) (vinyl) dimethylsilane, (chloro) (methyl) diphenylsilane, (methoxy) (methyl) diphenylsilane, (ethoxy) (methyl ) Diphenylsilane and the like. These silane compounds may be used alone or in combination of two or more.

<Synthesis method of polysiloxane>
Polysiloxane can be synthesized, for example, by hydrolytic condensation of the above-mentioned silane compound or the like. The conditions for the above hydrolytic condensation are not particularly limited as long as at least a part of the silane compound is hydrolyzed to convert the hydrolyzable group into a silanol group and cause a condensation reaction. However, it can be implemented as follows as an example.

  The water used for the hydrolysis condensation is preferably water purified by a method such as reverse osmosis membrane treatment, ion exchange treatment or distillation. By using such purified water, side reactions can be suppressed and the reactivity of hydrolysis can be improved. The amount of water used is preferably 0.1 mol to 3 mol, more preferably 0.3 mol to 2 mol, and still more preferably 0.5 mol with respect to 1 mol of the total amount of hydrolyzable groups of the silane compound. The amount is from mol to 1.5 mol. By using such an amount of water, the hydrolysis / condensation reaction rate can be optimized.

  As the solvent that can be used for the hydrolysis condensation, for example, ethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate, and propionic acid esters are preferable. Among these, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, methyl 3-methoxypropionate, 4-hydroxy-4-methyl-2-pentanone (diacetone Alcohol) is more preferred.

  The hydrolysis condensation reaction is preferably performed in the presence of a catalyst such as an acid catalyst, a base catalyst, or an alkoxide. The amount of the catalyst used is preferably 0.2 mol or less, more preferably 0.00001 mol to 0.1 mol with respect to 1 mol of the monomer of the hydrolyzable silane compound from the viewpoint of promoting the hydrolysis condensation reaction. .

  Although the reaction temperature and reaction time in the said hydrolysis condensation can be set suitably, as said reaction temperature, 40 to 200 degreeC is preferable and 50 to 150 degreeC is more preferable. The reaction time is preferably 30 minutes to 24 hours, and more preferably 1 hour to 12 hours. By setting such reaction temperature and reaction time, the hydrolysis condensation reaction can be performed most efficiently. In this hydrolysis condensation, the reaction may be carried out in one step by adding the hydrolyzable silane compound, water and catalyst to the reaction system at once, and the hydrolyzable silane compound, water and catalyst may be added several times. The hydrolysis and condensation reaction may be performed in multiple stages by separately adding it to the reaction system. After the hydrolysis condensation reaction, water and the produced alcohol can be removed from the reaction system by adding a dehydrating agent and then subjecting it to evaporation.

  [B] The solution viscosity of the polymer is preferably 10 mPa · s to 800 mPa · s, more preferably 15 mPa · s to 500 mPa · s, when the solution has a concentration of 10% by mass. In addition, the solution viscosity (mPa · s) of the [B] polymer has a concentration of 10 masses prepared using a good solvent for the [B] polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). % Of the polymer solution measured at 25 ° C. using an E-type rotational viscometer.

  [B] The content of the polymer is preferably 80% by mass or more, and more preferably 90% by mass or more based on the total solid content.

  [B] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. And ratio (Mw / Mn) of polystyrene conversion number average molecular weight (Mn) measured by Mw and gel permeation chromatography (GPC) becomes like this. Preferably it is 15 or less, More preferably, it is 10 or less. By being in such a range, the favorable orientation and stability of a liquid crystal display element are securable.

<[C] solvent>
The liquid crystal aligning agent usually contains a [C] solvent. [C] As the solvent, those which uniformly dissolve or disperse each component such as the [A] compound and [B] polymer and do not react with each component are used. [C] Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents and the like. In addition, you may use a [C] solvent individually or in combination of 2 or more types.

As the alcohol solvent, for example,
As monoalcohol solvents, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec -Pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-he Data decyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, diacetone alcohol and the like;
As polyhydric alcohol solvents, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2 , 4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and the like;
As polyhydric alcohol partial ether solvents, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl Ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, propylene glycol monomethyl ether, propylene glycol Monoethyl ether, propylene glycol -n- propyl ether, propylene glycol mono -n- butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono -n- propyl ether.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl- n-hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, etc. Can be mentioned.

  Examples of the amide solvent include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethyl. Examples include acetamide, N-methylpropionamide, N-methyl-2-pyrrolidone and the like.

As the ether solvent, for example,
Examples of aliphatic ethers include diethyl ether, dipropyl ether, dibutyl ether, butyl methyl ether, butyl ethyl ether, diisoamyl ether, hexyl methyl ether, octyl methyl ether, cyclopentyl methyl ether, dicyclopentyl ether and the like;
Aliphatic-aromatic ethers such as anisole and phenylethyl ether;
Examples of cyclic ethers include tetrahydrofuran, tetrahydropyran, dioxane and the like.

  Examples of the ester solvent include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate. N-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, Ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-acetate -Butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxy acetate Triglycol, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate Dimethyl phthalate, diethyl phthalate, γ-butyrolactone, and the like.

  [C] The solvent is preferably an alcohol solvent or an amide solvent, and the alcohol solvent is more preferably a polyhydric alcohol partial ether solvent, more preferably ethylene glycol mono-n-butyl ether. As the amide solvent, N-methyl-2-pyrrolidone is more preferable.

  [C] The content of the solvent is appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration in the liquid crystal aligning agent (the total mass of components other than the solvent of the liquid crystal aligning agent is The ratio to the total mass) is preferably 1% by mass to 10% by mass. When the solid content concentration is less than 1% by mass, it is difficult to obtain a good liquid crystal alignment film because the film thickness of the formed liquid crystal alignment film is too small. It is difficult to obtain a good liquid crystal alignment film because the film thickness is excessive. Moreover, when the said solid content concentration exceeds 10 mass%, there exists a tendency for the viscosity of a liquid crystal aligning agent to increase and for applicability | paintability to fall.

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

<Other optional components>
Examples of other optional components that the liquid crystal aligning agent may contain include an epoxy group-containing compound, an antioxidant, a polyfunctional (meth) acrylate, and a functional silane compound. Hereinafter, each component will be described.

(Epoxy group-containing compound)
An epoxy group containing compound is a component which improves adhesiveness. The liquid crystal aligning film formed from the said liquid crystal aligning agent can improve adhesiveness with a board | substrate because the said liquid crystal aligning agent contains this epoxy group containing compound. In addition, you may use this epoxy group containing compound individually or in combination of 2 or more types.

  Examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 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′-diame Examples include diphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine, and an epoxy group-containing polyorganosiloxane described in WO2009 / 096598. .

  As content of the said epoxy group containing compound, 0 mass part-40 mass parts are preferable with respect to 100 mass parts of all the polymers which the said liquid crystal aligning agent contains, and 0.1 mass part-30 mass parts are more preferable. .

(Antioxidant)
Antioxidants are components that function as radical scavengers or peroxide decomposers that invalidate peroxy radicals and hydroperoxides generated due to energy such as ultraviolet rays and heat. The liquid crystal aligning agent can suppress the deterioration of the electrical characteristics of the liquid crystal display element due to peroxy radicals and the like by containing this antioxidant. In addition, you may use this antioxidant individually or in combination of 2 or more types.

  Examples of the antioxidant include phenolic antioxidants, amine antioxidants, phosphorus antioxidants, sulfur antioxidants, blended antioxidants, and the like. As these antioxidants, for example, the following commercially available products can be used.

Examples of the phenol-based antioxidant include ADK STAB AO-20, AO-30, AO-40, AO-50, AO-60, AO-80, and AO-330 (above, manufactured by ADEKA). IRGANOX1010, IRGANOX1035, IRGAOX1076, IRGANOX1098, IRGANOX1135, IRGANOX1330, IRGANOX1726, IRGANOX1425, IRGANOX1520, IRGANOX245, IRGANOX259, IRGANOX3114, IRGANOX3790, IRGANOX3790, IRGANOX3790, IRGANOX3790
Examples of the amine-based antioxidant include ADK STAB LA-52, LA-57, LA-63, LA-68, LA-72, LA-77, LA-81, LA-81, LA-82, LA- 87, LA-402, LA-502 (above, manufactured by ADEKA), CHIMASSORB 119, CHIMASSORB 2020, CHIMASSORB 944, TINUVIN 622, TINUVIN 123, TINUVIN 144, TINUVIN 765, TINUVIN 770, TINUVIN 111, TINUVIN 791, FIN, etc.
Examples of the phosphorus antioxidant include ADK STAB PEP-4C, PEP-8, PEP-36, HP-10, 2112 (above, manufactured by ADEKA), IRGAFOS168, GSY-P101 (above, manufactured by Sakai Chemical Industry, Ltd.) ), IRGAFOS168, IRGAFOS12, IRGAFOS126, IRGAFOS38, IRGAFOS P-EPQ (above, manufactured by BASF Japan) and the like.
Examples of the sulfur-based antioxidant include ADK STAB AO-412, AO-503 (manufactured by ADEKA), IRGANOX PS 800, IRGANOX PS 802 (manufactured by BASF Japan), and the like.
Examples of the blended antioxidant include ADK STAB A-611, A-612, A-613, AO-37, AO-15, AO-18, 328 (above, manufactured by ADEKA), TINUVIN111. TINUVIN 783, TINUVIN 791 (above, manufactured by BASF Japan) and the like.
Of these, phenol-based antioxidants and amine-based antioxidants are preferred.

  As content of the said antioxidant, 0 mass part-10 mass parts are preferable with respect to 100 mass parts of all the polymers which the said liquid crystal aligning agent contains, 0 mass part-5 mass parts are more preferable, and 0. 1 part by mass to 3 parts by mass is more preferable.

(Multifunctional (meth) acrylate)
Polyfunctional (meth) acrylate is a component which improves a weather resistance. The liquid crystal aligning agent can improve the weather resistance of a liquid crystal display element by containing this polyfunctional (meth) acrylate. In addition, you may use this polyfunctional (meth) acrylate individually or in combination of 2 or more types.

  Examples of the polyfunctional (meth) acrylate include ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol diacrylate, 1 , 9-nonanediol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, bisphenoxyethanol full orange acrylate, bisphenoxyethanol full orange methacrylate, trimethylolpropane triacrylate, trimethylol Propane trimethacrylate, pentaerythritol triacrylate, Taerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, tri (2-acryloyloxyethyl) phosphate, And tri (2-methacryloyloxyethyl) phosphate. In addition, as a polyfunctional (meth) acrylate, you may use a commercial item.

  As content of the said polyfunctional (meth) acrylate, 0 mass part-100 mass parts are preferable with respect to 100 mass parts of all the polymers which the said liquid crystal aligning agent contains, and 0 mass part-50 mass parts are more preferable. 0.1 part by mass to 30 parts by mass is more preferable.

(Functional silane compound)
A functional silane compound is a component which improves applicability | paintability. The liquid crystal aligning agent can improve the applicability | paintability to the board | substrate of a liquid crystal aligning agent by containing this functional silane compound. In addition, you may use this functional silane compound individually or in combination of 2 or more types.

  Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, and N- (2-aminoethyl). -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-amino Propyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, , 7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9 -Triethoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazananoate, methyl 9-triethoxysilyl-3,6-diazananoate, N-benzyl-3-aminopropyl Trimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycid Xymethyltriethoxysilane, 2-glycidoxyethyltrime Kishishiran, 2-glycidoxyethyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, and the like.

  As content of the said functional silane compound, 0 mass part-2 mass parts are preferable with respect to 100 mass parts of all the polymers which the said liquid crystal aligning agent contains, 0.02 mass part-0.2 mass part are preferable. More preferred.

<Method for preparing liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention includes [A] compound, [B] polymer, [C] solvent, epoxy group-containing compound, antioxidant, polyfunctional (meth) acrylate, functional silane compound, etc. as necessary. It can be prepared by mixing arbitrary components at a predetermined ratio. The temperature during the preparation is preferably 10 ° C to 50 ° C, more preferably 20 ° C to 30 ° C. Further, the liquid crystal aligning agent may be prepared by mixing each of the above components and then filtering with a filter having a pore diameter of about 1 μm, for example.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is formed from the liquid crystal alignment agent. Since the liquid crystal alignment film is formed from the liquid crystal aligning agent containing the [A] compound and the [B] polymer, the liquid crystal display element including the liquid crystal alignment film has excellent light resistance.

<Method for forming liquid crystal alignment film>
Examples of the liquid crystal alignment film include (1) a step of forming a coating film on a substrate using the liquid crystal alignment agent (hereinafter, also referred to as “step (1)”), and (2) rubbing the coating film. It can be formed through a step of forming an alignment film (hereinafter also referred to as “step (2)”). Step (1) differs depending on the driving method of the liquid crystal display element. Hereinafter, the steps (1) and (2) will be described in detail.

[Step (1)]
At this process, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, and a coating film is formed on the said board | substrate by heating an application surface then.

  When the liquid crystal display element is a TN-type, STN-type, or VA-type liquid crystal display element, first, a pair of two substrates provided with a patterned transparent conductive film is formed, and the liquid crystal is formed on each transparent conductive film formation surface. Apply alignment agent.

Examples of the substrate include glass such as float glass and soda glass; and transparent substrates made of plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). Examples of the transparent conductive film include a 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 ), and the like. As a method of providing the 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 mask having a desired pattern when forming the transparent conductive film And the like. As a method for applying the liquid crystal aligning agent, an offset printing method, a spin coating method, a roll coater method, and an ink jet printing method are preferable. In addition, in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film when applying the liquid crystal aligning agent, a functional silane compound or functional titanium is formed on the surface of the substrate surface on which the coating film is to be formed. You may give the pretreatment which apply | coats a compound etc. previously.

  After applying the liquid crystal aligning agent, it is preferable to perform preheating (pre-baking) for the purpose of preventing dripping of the applied liquid crystal aligning agent. As prebaking temperature, 30 to 200 degreeC is preferable, 40 to 150 degreeC is more preferable, and 40 to 100 degreeC is further more preferable. The pre-bake time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Thereafter, the solvent may be completely removed, and if necessary, baking (post-baking) may be performed to thermally imidize the amic acid structure in the [B] polymer. As post-baking temperature, 80 to 300 degreeC is preferable and 120 to 250 degreeC is more preferable. The post-bake time is preferably 5 minutes to 200 minutes, and more preferably 10 minutes to 100 minutes. The thickness of the liquid crystal alignment film to be formed is preferably 1 nm to 1,000 nm, and more preferably 5 nm to 500 nm.

  When the liquid crystal display element is an IPS liquid crystal display element, the conductive film forming surface of the substrate provided with the comb-shaped transparent conductive film and the one surface of the counter substrate provided with no conductive film A liquid crystal aligning agent is each apply | coated and then a coating film is formed by heating each application | coating surface. Regarding the material of the substrate and transparent conductive film used 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 coating film to be formed, the above-mentioned TN The same as the case of the type, STN type and VA type liquid crystal display elements.

  In the case of any of the above-described liquid crystal display elements, when the polymer [B] is a polyamic acid or an imidized polymer having an imide ring structure and an amic acid structure, after the coating film is formed. Further, the dehydration cyclization reaction may be advanced by heating to form a more imidized coating film.

[Step (2)]
In this step, a liquid crystal alignment film is formed by rubbing the coating film.
When the liquid crystal display element is a TN type, STN type or IPS type liquid crystal display element, the coating film formed in the above step (1) is fixed in a certain direction with a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. Apply rubbing treatment. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film.
When the liquid crystal display element is a VA liquid crystal display element, the coating film formed in the step (1) can be used as it is as the liquid crystal alignment film, but the formed coating film may be rubbed.

  For the liquid crystal alignment film formed as described above, 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 liquid crystal alignment film Form a resist film on a part of the surface, and then perform a rubbing process in a direction different from the previous rubbing process, and then perform a process to remove the resist film, so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region. It may be. In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element. Note that a liquid crystal alignment film suitable for a VA liquid crystal display element can also be suitably used for a PSA (Polymer Sustained Alignment) liquid crystal display element.

<Liquid crystal display element>
The liquid crystal display element of the present invention includes the liquid crystal alignment film. This liquid crystal display element is comprised by the liquid crystal cell, polarizing plate, etc. which are mentioned later. Since the liquid crystal display element includes a liquid crystal alignment film formed from the liquid crystal alignment agent, the liquid crystal display element has excellent light resistance.

  The driving method of the liquid crystal display element is not particularly limited, and can be applied to various driving methods such as an IPS type, a TN type, an STN type, an FFS type, a VA type, and an OCB type. The liquid crystal display element includes a pair of substrates on the surface of which a transparent electrode and a liquid crystal alignment film are laminated in this order. The pair of substrates are disposed to face each other, and liquid crystal is filled between the pair of substrates. The peripheral part is sealed with a sealant.

<Method for manufacturing liquid crystal display element>
The liquid crystal display element uses, for example, a pair of substrates on which a liquid crystal alignment film is formed by the above steps (1) and (2), and (3) a liquid crystal between a pair of substrates on which the liquid crystal alignment film is opposed. A step of forming a liquid crystal cell by filling (hereinafter also referred to as “step (3)”), (4) a step of attaching a polarizing plate to the outer surface of the liquid crystal cell (hereinafter also referred to as “step (4)”). ). Hereinafter, the steps (3) and (4) will be described in detail.

[Step (3)]
In this step, the two substrates on which the liquid crystal alignment films are formed are opposed to each other with a gap (cell gap) so that the rubbing directions of the liquid crystal alignment films are orthogonal or antiparallel, and the peripheral portions of the two substrates Are bonded together using a sealing agent, liquid crystal is injected and filled in the cell gap defined by the substrate surface and the sealing agent, and the injection hole is sealed to form a liquid crystal cell.

As said sealing agent, the epoxy resin etc. which contain the aluminum oxide sphere as a hardening | curing agent and a spacer are mentioned, for example.
Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Of these, nematic liquid crystals are preferred. Examples of the nematic liquid crystal include a Schiff base liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenyl cyclohexane liquid crystal, an ester liquid crystal, a terphenyl liquid crystal, a biphenyl cyclohexane liquid crystal, a pyrimidine liquid crystal, a dioxane liquid crystal, and a bicyclooctane system. A liquid crystal, a cubane type liquid crystal, etc. are mentioned. In addition, these liquid crystals include, for example, cholesteric liquid crystals such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, etc .; trade names “C-15” and “CB-15” (manufactured by Merck). Chiral agent; ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate may be added.

[Step (4)]
In this step, a polarizing plate is bonded to the outer surface of the formed liquid crystal cell so that the polarization direction thereof matches or is orthogonal to the rubbing direction of the liquid crystal alignment film formed on each substrate.

  Examples of the polarizing plate include a polarizing plate in which a polarizing film called an “H film” in which iodine is absorbed while stretching and orientation of polyvinyl alcohol is sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself. Can be mentioned.

  The liquid crystal display element formed as described above can be effectively applied to various devices. For example, watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones It can be used for various display devices such as telephones, smartphones, various monitors, liquid crystal televisions, and information displays.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. The measuring method of each physical property value is shown below.

[Solution viscosity of polymer solution]
[B] The solution viscosity (mPa · s) of the polymer solution is determined at 25 ° C. using an E-type rotational viscometer for a solution prepared by using a predetermined solvent and the concentration of [B] polymer at 10% by mass. It was measured.

[Imidation rate]
The polyimide solution was poured into pure water, and the resulting precipitate was sufficiently dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR spectrum was measured at room temperature using tetramethylsilane as a reference substance. did. From the obtained ¹ H-NMR spectrum, the imidation ratio (%) of polyimide was determined by the following mathematical formula (i).

  In the above formula (i), A1 is a peak area derived from protons of NH groups appearing in the vicinity of a chemical shift of 10 ppm. A2 is the peak area derived from other protons. α is the number ratio of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

<Synthesis of [A] Compound>
[Synthesis Example 1] (Synthesis of Compound (A-1))
As shown in the following scheme (3-1), 11.0 mmol (1.63 g) of 3,4-dihydrocoumarin, 10.0 mmol (1.08 g) of 3-aminomethylpyridine, and 10 ml of tetrahydrofuran were mixed. The mixture was stirred for 3 hours under reflux conditions. Next, after the reaction solution was concentrated to 5 ml, 30 ml of hexane was added, the precipitate was filtered, washed with hexane, dried, and the compound (A-1) represented as the reaction product of the following scheme (3-1) ) 9.87 mmol (2.53 g) was obtained.

[Synthesis Example 2] (Synthesis of Compound (A-2))
As shown in the following scheme (3-2), 11.0 mmol (1.63 g) of 3,4-dihydrocoumarin, 10.0 mmol (1.08 g) of 4-aminomethylpyridine, and 10 ml of tetrahydrofuran were mixed. The mixture was stirred for 3 hours under reflux conditions. Next, after the reaction solution was concentrated to 5 ml, 30 ml of hexane was added, the precipitate was filtered, washed with hexane, and dried, and the compound (A-2) represented by the reaction product of the following scheme (3-2) ) 9.65 mmol (2.47 g) was obtained.

[Synthesis Example 3] (Synthesis of Compound (A-3))
As shown in the following scheme (3-3), 20.0 mmol (2.96 g) of 3,4-dihydrocoumarin, 30.0 mmol (2.82 g) of 4-aminopyridine and 3 mL of dioxane were mixed, and 100 ° C. Stir for 24 hours under reflux conditions. Subsequently, after confirming the production | generation of the compound (A-3) represented as a reaction product of the following scheme (3-3) using thin layer chromatography (TLC), it refine | purified by silica gel column chromatography, and the following scheme 18.5 mmol (4.48 g) of compound (A-3) represented as a reaction product of (3-3) was obtained.

<[B] Synthesis of polymer>
[B] Tetracarboxylic dianhydrides and diamines used in the synthesis of the polymer are shown below.

[Tetracarboxylic dianhydride]
b1-1: 2,3,5-tricarboxycyclopentylacetic acid dianhydride (TCA)

[Diamine]
b2-1: Cholestanyl 3,5-diaminobenzoate (HCDA)
b2-2: Cholestanyloxy-2,4-diaminobenzene (HCODA)
b2-3: p-phenylenediamine (PDA)
b2-4: 3,5-diaminobenzoic acid (DAB)

[Synthesis Example 4] (Synthesis of Polymer (B-1))
0.1 mol (22.40 g) of (b1-1) as a tetracarboxylic anhydride and 0.02 mol (10.45 g) of (b2-1) and 0.01 mol of (b2-2) as a diamine ( 4.94 g) and 0.07 mol (7.56 g) of (b2-3) were dissolved in 181 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to contain 20% by mass of polyamic acid. A solution was obtained. A small amount of this solution was collected, and the viscosity of a solution prepared by adding N-methyl-2-pyrrolidone to a polyamic acid concentration of 10% by mass was 68 mPa · s.

  Next, 421 g of N-methyl-2-pyrrolidone was added to the obtained 20% by mass solution of polyamic acid, and 7.9 g of pyridine as a dehydrating ring closure catalyst and 10.2 g of acetic anhydride as a dehydrating agent were added at 110 ° C. The dehydration ring closure reaction was performed for 4 hours. After the dehydration cyclization reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone (by this solvent replacement operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same applies hereinafter). As a result, a solution containing 26% by mass of a polyimide polymer (B-1) having an imidation ratio of 51% was obtained. A small amount of this solution was collected, and the solution viscosity of a solution prepared by adding N-methyl-2-pyrrolidone to a polyimide concentration of 10% by mass was 50 mPa · s.

[Synthesis Example 5] (Synthesis of polymer (B-2))
A solution containing a polyimide polymer (B-2) having an imidization ratio of 74% was obtained in the same manner as in Synthesis Example 4 except that the blending amounts of pyridine and acetic anhydride used were as shown in Table 1 below. It was. The reaction solution was prepared by adding N-methyl-2-pyrrolidone so that the total amount of tetracarboxylic dianhydride and diamine was 20% by mass with respect to the total amount of the reaction solution.

[Synthesis Example 6] (Synthesis of polymer (B-3))
0.1 mol (22.40 g) of (b1-1) as a tetracarboxylic anhydride and 0.02 mol (10.45 g) of (b2-1) and 0.01 mol of (b2-2) as a diamine ( 4.95 g) and 0.07 mol (10.64 g) of (b2-4) were dissolved in 194 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours to contain 20% by mass of polyamic acid. A solution was obtained. A small amount of this solution was collected, and the viscosity of a solution prepared by adding N-methyl-2-pyrrolidone to a polyamic acid concentration of 10% by mass was 67 mPa · s.

  Next, 450 g of N-methyl-2-pyrrolidone was added to the obtained 20% by mass solution of polyamic acid, and 7.9 g of pyridine as a dehydrating ring closure catalyst and 10.2 g of acetic anhydride as a dehydrating agent were added at 110 ° C. The dehydration ring closure reaction was performed for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new N-methyl-2-pyrrolidone to obtain a solution containing 26% by mass of a polyimide polymer (B-3) having an imidization rate of 52%. It was. A small amount of this solution was collected, and the solution viscosity of a solution prepared by adding N-methyl-2-pyrrolidone to a polyimide concentration of 10% by mass was 49 mPa · s.

[Synthesis Example 7] (Synthesis of polymer (B-4))
A solution containing a polyimide polymer (B-4) having an imidization ratio of 73% was obtained in the same manner as in Synthesis Example 6 except that the blending amounts of pyridine and acetic anhydride used were as shown in Table 1 below. It was. The reaction solution was prepared by adding N-methyl-2-pyrrolidone so that the total amount of tetracarboxylic dianhydride and diamine was 20% by mass with respect to the total amount of the reaction solution.

  In Table 1, the numerical value of tetracarboxylic dianhydride indicates the usage ratio (mol%) of the compound of the type shown in Table 1 with respect to the total amount of tetracarboxylic dianhydride used in the synthesis. The numerical value of diamine indicates the usage ratio (mol%) of the compound of the type shown in Table 1 with respect to the total amount of diamine used in the synthesis. The numerical values of pyridine as a dehydration ring-closing catalyst and acetic anhydride as a dehydrating agent respectively indicate the use ratio (mol%) of pyridine and acetic anhydride to the number of amic acid units of the obtained polyamic acid. Table 1 shows the physical property values of the obtained polymers together. In addition, "-" in Table 1 indicates that the corresponding compound was not blended.

<Preparation of liquid crystal aligning agent>
Components other than the [A] compound and the [B] polymer used for the preparation of the liquid crystal aligning agent are shown below.

[[C] solvent]
NMP: N-methyl-2-pyrrolidone BC: Ethylene glycol mono-n-butyl ether

[Epoxy group-containing compound]
G-1: N, N, N ′, N′-tetraglycidyl-m-xylenediamine

[Example 1]
(1) Preparation of liquid crystal aligning agent for applicability evaluation [B] In a solution containing 100 parts by mass of (B-1) as a polymer, 5 parts by mass of (A-1) as a compound [A], and [C] N-methyl-2-pyrrolidone (NMP) and ethylene glycol-mono-n-butyl ether (BC) as a solvent are added, and [C] the composition of the solvent is NMP: BC = 50: 50 (mass ratio), A solution having a solid concentration of 6.5% by mass was obtained. The solution was filtered using a filter having a pore diameter of 1 μm to prepare a liquid crystal aligning agent for applicability evaluation (hereinafter, this liquid crystal aligning agent for applicability evaluation is also referred to as “liquid crystal aligning agent A”).
(2) Preparation of Liquid Crystal Alignment Agent for Reworkability and Light Resistance Evaluation In the preparation of the liquid crystal alignment agent in (1) above, the above (1) except that the solid content concentration of the solution before filtration was 4.0% by mass. ) To prepare a liquid crystal aligning agent for evaluating reworkability and light resistance (hereinafter, liquid crystal aligning agent for evaluating reworkability and light resistance is also referred to as “liquid crystal aligning agent B”). did.

[Examples 2-7 and Comparative Examples 1-8]
The [A] compound, the [B] polymer, the [C] solvent, and the epoxy group-containing compound to be blended were operated in the same manner as in Example 1 except that they were as shown in Table 2 below. About, liquid crystal aligning agent A and liquid crystal aligning agent B were obtained.

<Manufacture of liquid crystal display elements>
[Example 8]
The liquid crystal aligning agent B of Example 1 was apply | coated using the spinner on the transparent conductive film which consists of an ITO film | membrane provided in one surface of the 1 mm-thick glass substrate, and it heated on the 80 degreeC hotplate for 1 minute. Next, a liquid crystal alignment film having a thickness of about 80 nm was formed by heating on a hot plate at 230 ° C. for 30 minutes. This operation was repeated to produce a substrate having the required number of liquid crystal alignment films.
Next, after applying the epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm to the outer edges of the surfaces having the liquid crystal alignment film, the respective liquid crystal alignment film surfaces are applied to the pair of substrates having the liquid crystal alignment film. The adhesives were cured by overlapping and pressing them so that they face each other. Next, after filling negative liquid crystal (MLC-6608, manufactured by Merck) between a pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an acrylic photo-curing adhesive, and polarized on both sides of the substrate. A vertically aligned liquid crystal display element was manufactured by laminating the plates.

[Examples 9 to 14 and Comparative Examples 9 to 16]
A vertical alignment type liquid crystal display device was produced in the same manner as in Example 8 except that the liquid crystal alignment agent used was the liquid crystal alignment agent B of Examples 2 to 7 and Comparative Examples 1 to 8.

<Evaluation>
Each liquid crystal aligning agent prepared above and the liquid crystal display element manufactured above were evaluated according to the following methods. Of the following evaluation results, coating properties and reworkability are shown in Table 2, and light resistance is shown in Table 3.

[Applicability]
Using a liquid crystal alignment film printer (Angstromer type “S40L-532”, manufactured by Nissha Printing Co., Ltd.), each liquid crystal alignment agent A was dropped 20 times (about 0.2 g) into the anilox roll. ) On the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film. In addition, the drop amount normally employ | adopted with the same type printing machine is 30 drops (about 0.3g) of reciprocation, and it was set as stricter printing conditions here than usual.
Next, the substrate after application of the liquid crystal aligning agent A was heated (pre-baked) for 1 minute on a hot plate at 80 ° C., and then heated (post-baked) for 10 minutes on a hot plate at 180 ° C. A coating film was formed.
This coating film was observed with a microscope having a magnification of 20 times to examine whether the applied liquid crystal aligning agent had repellency or coating unevenness. At this time, when repelling and coating unevenness were not observed, applicability was “excellent (A)”, and when repelling and coating unevenness were slightly observed, “good (B)” was observed, and repelling and coating unevenness were observed. When clearly observed, it was evaluated as “defective (C)”.

[Reworkability]
Each of the liquid crystal alignment agents B is applied on a transparent conductive film made of an ITO film provided on one surface of a 1 mm thick glass substrate by a spinner, and pre-baked at 100 ° C. for 90 seconds on a hot plate. An 80 nm coating film was formed. This operation was repeated to produce three substrates with a coating film.
Next, the obtained substrate was stored in a dark room at 25 ° C. under a nitrogen atmosphere, taken out after 12 hours, 24 hours, and 72 hours, respectively, and placed in a beaker containing 40 ° C. N-methyl-2-pyrrolidone (NMP). Soaked for 2 minutes. Thereafter, the substrate was taken out of the beaker and washed several times with ultrapure water, and then water droplets on the surface were removed by air blow, and the remaining state of the coating film on the substrate was observed using an engineering microscope. At this time, if the coating film does not remain even in the substrate having a storage time of 72 hours in the dark room, the reworkability is “excellent (A)”, and the coating film can be peeled off if the storage time is 48 hours. If the coating film can be peeled off if it is “substantially good (B)” and the substrate is stored for 24 hours, “good (C)” is applied to the substrate that is stored for 12 hours. When the film could not be peeled, it was evaluated as “defective (D)”.

[Light resistance]
After applying a voltage of 5 V to each liquid crystal display element immediately after manufacturing at a temperature of 60 ° C. with an application time of 60 microseconds and a span of 167 milliseconds, the voltage holding ratio after 167 milliseconds from the release of application is obtained. It measured using the measuring apparatus (VHR-1, Toyo Technica make). This voltage holding ratio is defined as an initial voltage holding ratio VH ₁ (%).
Subsequently, each liquid crystal display element was irradiated with light for 1,000 hours using a weather meter using a carbon arc as a light source. About the liquid crystal display element after light irradiation, the voltage holding rate was measured by the method similar to the above. This voltage holding ratio is defined as a voltage holding ratio VH ₂ (%) after light irradiation.
At this time, a decrease amount of the voltage holding ratio obtained by subtracting VH ₂ from VH ₁ was set as ΔVHR, and ΔVHR was used as an index of light resistance. When ΔVHR is 4.0 or less, light resistance can be evaluated as good, and when it exceeds 4.0, it can be evaluated as defective.

  As shown in Tables 2 and 3, all of the liquid crystal display elements of the examples had good light resistance, and the liquid crystal aligning agent used for them had good coating properties and reworkability. On the other hand, in the comparative example, at least one of light resistance, coatability, and reworkability was poor.

  The present invention can provide a liquid crystal aligning agent that can form a liquid crystal display element having excellent light resistance and has high coating properties and reworkability. Therefore, the liquid crystal aligning agent, the liquid crystal aligning film formed from the liquid crystal aligning agent, and the liquid crystal display element including the liquid crystal aligning film are used in an electronic device capable of maintaining a high display quality over a long period of time and a manufacturing process thereof. It can be preferably used.

Claims (5)

[A] A compound represented by the following formula (1), and [B] a liquid crystal aligning agent containing a polymer.

(In the formula (1), R ¹ is a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a monovalent heterocyclic group having 4 to 20 carbon atoms, or an aromatic hydrocarbon group thereof. And some or all of the hydrogen atoms of the heterocyclic group are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, amino groups, monoalkylamino groups, dialkylamino groups, nitroso groups, mercapto groups, Sulfide group, silyl group, silanol group, sulfino group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, keto group, ester group, trifluoromethyl group, hydroxy group, halogen atom, cyano group, nitro group, R ² is a group substituted with a carboxy group or a sulfo group, R ² is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms R ³ and R ⁴ Are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms, m is an integer of 0 to 2. When m is 2, two R ^{2 s} are the same or different. N is 1 or 2. When n is 2, two R ^{3 s} may be the same or different, r is an integer of 0 to 12. r is 2 or more In this case, the plurality of R ⁴ may be the same or different.)   [B] The liquid crystal aligning agent according to claim 1, wherein the polymer is at least one selected from the group consisting of polyamic acid, polyimide and polysiloxane.   [B] The liquid crystal aligning agent according to claim 2, wherein the polymer is at least one selected from the group consisting of polyamic acid and polyimide.   The liquid crystal aligning film formed from the liquid crystal aligning agent of Claim 1, Claim 2, or Claim 3.   A liquid crystal display element provided with the liquid crystal aligning film of Claim 4.