JP6314488B2 - Liquid crystal aligning agent, liquid crystal aligning film, liquid crystal display element, retardation film and method for producing retardation film - Google Patents

Description

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

  Conventionally, as a liquid crystal display element, various drive systems having different electrode structures, physical properties of liquid crystal molecules to be used, manufacturing processes, and the like have been developed. For example, TN type, STN type, VA type, in-plane switching type (IPS type) ), Various liquid crystal display elements such as FFS 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 or polyimide is generally used from the viewpoints of various properties such as heat resistance, mechanical strength, and affinity with liquid crystal.

  In recent years, large-screen, high-definition LCD TVs have become the mainstream, and demands for reducing display defects such as display unevenness and afterimages have become stricter, and reliability that can withstand long-term use in harsh usage environments A high liquid crystal display element is required. Various liquid crystal aligning agents have been proposed to satisfy these requirements. Moreover, various liquid crystal aligning agents which use polyamic acid ester for at least one part of a polymer component are proposed as one aspect (for example, refer patent documents 1-3).

  In Patent Document 1, two kinds of polyamic acid esters having a specific structure are contained in a liquid crystal aligning agent, thereby exhibiting good liquid crystal alignment and electrical characteristics even when the firing temperature is a low temperature of less than 200 ° C. It has been proposed to obtain a liquid crystal display element in which defects are unlikely to occur. Patent Document 2 proposes a liquid crystal aligning agent that contains a polyamic acid ester and a polyamic acid as polymer components, and the weight average molecular weight of the polyamic acid ester is smaller than the weight average molecular weight of the polyamic acid. According to the liquid crystal aligning agent described in Patent Document 2, it is described that fine unevenness generated on the film surface in the liquid crystal alignment film can be reduced, and the liquid crystal alignment and electrical characteristics in the liquid crystal display element can be improved.

  Patent Document 3 proposes a liquid crystal aligning agent containing a polyamic acid ester and a soluble polyimide. In the thing of this patent document 3, even if an imidation ratio is high, it does not raise | generate a whitening phenomenon at the time of coating-film formation, printability and the rubbing resistance of a coating film are favorable, and the liquid crystal orientation in a liquid crystal display element and It is described that electrical characteristics can be improved. In addition, in the liquid crystal aligning agent currently disclosed by the Example of patent document 3, the imidation ratio of a polyimide is 90% or 86%, and the polyimide with a comparatively high imidation ratio is mix | blended.

  In addition, various optical materials are used for liquid crystal display elements. Above all, retardation films eliminate the object of viewing color dependency and the viewing angle dependency that the display color and contrast ratio change depending on the visual direction. It is used for the purpose. As such retardation films, those having a liquid crystal alignment film formed on the surface of a substrate such as a TAC film and a liquid crystal layer formed by curing a polymerizable liquid crystal on the surface of the liquid crystal alignment film are known. ing. In recent years, a liquid crystal alignment film in a retardation film has been produced by using a photo-alignment method that imparts liquid crystal alignment ability by irradiating a radiation-sensitive organic thin film formed on the substrate surface with polarized or non-polarized radiation. Various liquid crystal aligning agents for retardation films for producing a liquid crystal alignment film by such a method have been proposed (see, for example, Patent Document 4).

JP 11-335461 A International Publication No. 2011/115078 International Publication No. 2013/147083 JP 2012-37868 A

  In recent years, demands for higher definition and longer life for liquid crystal displays are increasing, and further improvements in electrical characteristics and liquid crystal orientation are required. In addition, with the recent diversification of liquid crystal display elements, it is assumed that the liquid crystal display elements are used in more severe situations. Therefore, a liquid crystal display element having excellent heat resistance is required.

  A liquid crystal display is manufactured by disposing a pair of substrates on which a liquid crystal alignment film is formed facing each other and disposing a liquid crystal between the pair of facing substrates. In that case, a pair of board | substrates are bonded together using sealing agents, such as an epoxy resin. Here, in touch panel type display panels represented by smartphones and tablet PCs, attempts have been made to narrow the frame in order to achieve a wider movable area of the touch panel and a reduction in the size of the liquid crystal panel (element). ing. Further, along with the narrowing of the frame of the liquid crystal panel, display unevenness may be visually recognized around the sealant due to aging and the like, and the display quality is not fully satisfactory. In order to achieve high definition and long life of the liquid crystal display, a liquid crystal display element in which display unevenness around the sealant is hardly visible for a long time (high bezel unevenness resistance) is required.

  The present invention has been made in view of the above problems, and provides a liquid crystal display element that has little occurrence of display unevenness around the sealant over a long period of time and has various characteristics such as electrical characteristics, liquid crystal orientation, and heat resistance in a well-balanced manner. One object is to provide a liquid crystal aligning agent to be obtained.

  As a result of intensive studies to solve the problems of the prior art as described above, the present inventors have solved the above problems by making the polymer component of the liquid crystal aligning agent a blend system of a polyamic acid ester and a specific polyimide. The present inventors have found that the problem can be solved and have completed the present invention. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display element, retardation film, and method for producing the same.

  This invention provides the liquid crystal aligning agent which contains the polyamic acid ester which has a repeating unit represented by following formula (1), and a polyimide in one side surface, and the imidation ratio of this polyimide is 75% or less. .

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜５のアルキル基であり、Ｒ^３及びＲ^４は、それぞれ独立に水素原子又は置換若しくは無置換の炭素数１〜１０の１価の鎖状炭化水素基である。Ｘ^１は４価の有機基であり、Ｙ^１は２価の有機基である。）

(In formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 5 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or a substituted or unsubstituted carbon atom having 1 to 5 carbon atoms. 10 is a monovalent chain hydrocarbon group, X ¹ is a tetravalent organic group, and Y ¹ is a divalent organic group.)

  In one aspect, the present invention provides a liquid crystal alignment film formed using the liquid crystal alignment agent. Moreover, a liquid crystal display element provided with the said liquid crystal aligning film and a phase difference film provided with the said liquid crystal aligning film are provided. Furthermore, in another aspect, the step of coating the liquid crystal aligning agent on a substrate to form a coating film, the step of irradiating the coating film with light, and the polymerization on the coating film after the light irradiation And a step of applying and curing a liquid crystal.

  According to the liquid crystal alignment agent of the present invention, the liquid crystal alignment for obtaining a liquid crystal display element having a good balance of various properties such as electrical characteristics, liquid crystal alignment properties, and heat resistance with little display unevenness around the sealant over a long period of time. A film can be formed. Moreover, according to the liquid crystal aligning agent of this invention, a retardation film with favorable liquid crystal aligning property can be obtained.

The schematic block diagram of a FFS type liquid crystal cell. The plane schematic diagram of a top electrode. (A) is a top view of a top electrode, (b) is the elements on larger scale of a top electrode.

  The liquid crystal aligning agent of this invention contains polyamic acid ester and a polyimide as a polymer component. Below, each component contained in the liquid crystal aligning agent of this invention and the other component arbitrarily mix | blended as needed are demonstrated.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜５のアルキル基であり、Ｒ^３及びＲ^４は、それぞれ独立に水素原子又は置換若しくは無置換の炭素数１〜１０の１価の鎖状炭化水素基である。Ｘ^１は４価の有機基であり、Ｙ^１は２価の有機基である。） <Polyacic acid ester>
The polyamic acid ester contained in the liquid crystal aligning agent of this invention has a repeating unit represented by following formula (1).

(In formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 5 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or a substituted or unsubstituted carbon atom having 1 to 5 carbon atoms. 10 is a monovalent chain hydrocarbon group, X ¹ is a tetravalent organic group, and Y ¹ is a divalent organic group.)

Examples of the alkyl group having 1 to 5 carbon atoms in R ¹ and R ² of the above formula (1) include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. It may be in the shape. Preferably it is C1-C3, More preferably, it is a methyl group or an ethyl group.
The monovalent chain hydrocarbon group having 1 to 10 carbon atoms in R ³ and R ⁴ may be saturated or unsaturated, specifically, an alkyl group having 1 to 10 carbon atoms, or 2 to 10 carbon atoms. An alkenyl group, a C2-C10 alkynyl group, etc. are mentioned. These may be linear or branched. R ³ and R ⁴ may have a substituent, and examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, and an alkoxy group. It is done.

  Here, in the present specification, the “hydrocarbon group” means a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “chain hydrocarbon group” means a hydrocarbon group that does not include a cyclic structure in the main chain and is composed only of a chain structure. However, the chain structure may be linear or branched. The “alicyclic hydrocarbon group” means a hydrocarbon group that includes only an alicyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, it is not necessary to be comprised only by the structure of an alicyclic hydrocarbon, The thing which has a chain structure in the part is also included. The “aromatic hydrocarbon group” means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic hydrocarbon structure.

Examples of the organic group for X ¹ and Y ¹ include a hydrocarbon group such as a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group; —O— between the carbon-carbon bonds of the hydrocarbon group. , —COO—, —CO—, —NHCO—, —S—, —NH—, —SO ₂ — or the like; a hydrogen atom in the hydrocarbon group is a halogen atom, a hydroxyl group, or a nitro group And the like; groups having a heterocyclic ring, and the like.

  The polyamic acid ester having a repeating unit represented by the above formula (1) can be synthesized according to an organic chemistry method. For example, [I] a method of reacting a polyamic acid and an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester and a diamine, [III] a method of reacting a tetracarboxylic acid diester dihalide and a diamine, etc. Can be synthesized.

-About method [I] The polyamic acid used by method [I] can be obtained by making tetracarboxylic dianhydride and diamine react.
(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. it can. Specific examples of these include aliphatic tetracarboxylic dianhydrides such as butane tetracarboxylic 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) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3- Yl) -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, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-di Anhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid 2: 3,5: 6-dianhydride, 4,9-dioxatricyclo [5.3.1] .0 ^2,6] undecane -3,5,8,10- tetraone, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene -2, 3,5,6-tetracarboxylic dianhydride and the like;
Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride and the like; respectively, and tetracarboxylic dianhydrides described in JP 2010-97188 A can be used. In addition, as tetracarboxylic dianhydride used for the synthesis | combination of a polyamic acid, these 1 type can be used individually or in combination of 2 or more types.

  The tetracarboxylic dianhydride used for the synthesis of the polyamic acid is bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid 2 from the viewpoint of liquid crystal alignment and solubility in a solvent. : 3,5: 6-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxo Tetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl ) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-dianhydride At least one compound selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and pyromellitic dianhydride (hereinafter also referred to as “specific tetracarboxylic dianhydride”). It is preferable to include.

The amount of the specific tetracarboxylic dianhydride used is preferably 5 mol% or more, preferably 10 mol% or more, based on the total amount of tetracarboxylic dianhydride used for the synthesis of polyamic acid. More preferably, it is particularly preferably 20 mol% or more. The tetracarboxylic dianhydride used for the synthesis of the polyamic acid can be used alone or in combination of two or more. Incidentally, X ¹ in the formula (1) is a structural unit derived from the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid.

(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 thereof include aliphatic diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, and the like; alicyclic diamines such as 1,4- Diaminocyclohexane, 4,4′-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;

（式（ａ−１）中、Ｘ^I及びＸ^IIは、それぞれ独立に、単結合、−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−であり、Ｒ^Ｉ及びＲ^ＩＩは、それぞれ独立に、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。） As aromatic diamines, for example, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 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) Suaniline, 4,4 ′-(m-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole N-phenyl-3,6-diaminocarbazole, N, N′-bis (4-aminophenyl) -benzidine, N, N′-bis (4-aminophenyl) -N, N′-dimethylbenzidine, 1, 4-bis- (4-aminophenyl) -piperazine, 3,5-diaminobenzoic acid, dodecanoxy-2,4-diaminobenzene, teto Decanoxy-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-diaminobenzene, 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, 3,5-diaminobenzene Lanostanyl perfate, 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) cyclohexa 2,4-diamino-N, N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, 1- (2,4-diaminophenyl) piperazine-4-carboxylic acid, 4- (morpholine-4- Yl) benzene-1,3-diamine, 1,3-bis (N- (4-aminophenyl) piperidinyl) propane, α-amino-ω-aminophenylalkylene, 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, 4-aminophenyl-4′-aminobenzoate, 4,4 ′-[4,4′-propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline, and the following formula (a 1)

(In Formula (a-1), X ^I and X ^II are each independently a single bond, —O—, —COO— or —OCO—, and R ^I and R ^II are each independently a carbon number. 1 to 3 alkanediyl groups, a is 0 or 1, b is an integer of 0 to 2, c is an integer of 1 to 20, and d is 0 or 1, provided that a and b is never 0 at the same time.)

A compound represented by:
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 ) _n —” in the formula (a-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. Specific examples of the group “—C _c H _{2c + 1} ” include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, and 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 and the like. 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 (a-1) include compounds represented by the following formulas (a-1-1) to (a-1-3).

The diamine used for the reaction preferably contains an aromatic diamine from the viewpoint of liquid crystal alignment and electrical characteristics. Incidentally, Y ¹ in the formula (1) is a structural unit derived from a diamine used in the synthesis of the polyamic acid. The diamine used for the synthesis | combination of a polyamic acid can be used individually by 1 type of these compounds or in combination of 2 or more types.

(Synthesis of polyamic acid)
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.

In the synthesis of the polyamic acid, a terminal-modified polymer may be synthesized using an appropriate molecular weight regulator together with the tetracarboxylic dianhydride and diamine as described above. By using such a terminal-modified polymer, the coating property (printability) 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 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 regulator 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 are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol and halogen. It is preferable to use one or more selected from the group consisting of fluorinated phenols as a solvent, or to use a mixture of one or more of these and another organic solvent in the above range.
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 subjected to the reaction with the esterifying agent as it is, may be subjected to the reaction with the esterifying agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid may be used. You may refine | purify and use for reaction with an esterifying agent. Isolation and purification of the polyamic acid can be performed according to known methods.

  Examples of the esterifying agent to be reacted with the polyamic acid 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 reaction between the polyamic acid and the esterifying agent is preferably performed in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 200 ° C., more preferably 0 to 120 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.
As the organic solvent used in the reaction, the description of the organic solvent that can be used for the synthesis of the polyamic acid can be applied. Specifically, N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone and the like can be preferably used. The amount of the organic solvent used is preferably such that the polyamic acid is 0.1 to 50% by weight based on the total amount of the reaction solution. The amount of the esterifying agent used is preferably 0.002 to 10 mol, and more preferably 0.02 to 6 mol, per 1 mol of the polyamic acid repeating unit.

-About Method [II] The tetracarboxylic acid diester used in Method [II] is obtained, for example, by opening the tetracarboxylic dianhydride exemplified above with alcohols such as methanol, ethanol, propanol and the like. be able to. Examples of the diamine to be reacted with the tetracarboxylic acid diester include the compounds exemplified as the diamine that can be used for the synthesis of the polyamic acid. The ratio of the tetracarboxylic acid diester and the diamine used in the polyamic acid ester synthesis reaction is such that the carboxyl group of the tetracarboxylic acid diester is 0.2 to 2 equivalents relative to 1 equivalent of the amino group of the diamine. A ratio of 0.3 to 1.2 equivalents is more preferable.

The reaction between the tetracarboxylic acid diester and the diamine is preferably carried out in an organic solvent in the presence of a dehydration catalyst and a base. 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.
As the organic solvent used for the reaction, the description of the organic solvent that can be used for the synthesis of the polyamic acid can be applied. Among them, N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. Can be preferably used. The amount of the organic solvent used is preferably such that the total amount of the tetracarboxylic acid diester and diamine is 0.1 to 50% by weight based on the total amount of the reaction solution.

Examples of the dehydration catalyst used in the above reaction include 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium halide, carbonylimidazole, dicyclohexylcarbodiimide, and phosphorus-based condensation. Agents and the like. The amount of the condensing agent used is preferably 2 to 3 mol, and more preferably 2 to 2.5 mol, per 1 mol of the tetracarboxylic acid diester.
As the base, for example, tertiary amines such as pyridine and triethylamine can be preferably used. The amount of the base used is preferably 2 to 4 mol and more preferably 2 to 3 mol with respect to 1 mol of the diamine. The above reaction may be performed in the presence of a Lewis acid for the purpose of promoting the progress of the reaction. Examples of the Lewis acid include lithium halides such as lithium chloride.

-Method [III] The tetracarboxylic acid diester dihalide used in Method [III] is obtained by reacting the tetracarboxylic acid diester obtained as described above with an appropriate chlorinating agent such as thionyl chloride. Can do. Examples of the diamine to be reacted with the tetracarboxylic acid diester dihalide include compounds exemplified as the diamine that can be used for the synthesis of the polyamic acid. The ratio of the tetracarboxylic acid diester dihalide and the diamine used in the polyamic acid ester synthesis reaction is such that the tetracarboxylic acid diester dihalide group “—COX (X is a halogen atom) relative to 1 equivalent of the amino group of the diamine. ) "Is preferably 0.2 to 2 equivalents, more preferably 0.3 to 1.2 equivalents.

  The reaction between the tetracarboxylic acid diester dihalide and the diamine is preferably carried out in an organic solvent in the presence of a base. The reaction temperature at this time is preferably −30 ° C. to 150 ° C., more preferably −10 to 100 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours. As the organic solvent used for the reaction, the description of the organic solvent that can be used for the synthesis of the polyamic acid can be applied. The amount of the organic solvent used is preferably such that the total amount of the tetracarboxylic acid diester dihalide and the diamine is 0.1 to 50% by weight based on the total amount of the reaction solution. As the base used in the above reaction, for example, tertiary amines such as pyridine and triethylamine can be preferably used. The amount of the base used is preferably 2 to 4 mol and more preferably 2 to 3 mol with respect to 1 mol of the diamine.

  In this way, a reaction solution containing a polyamic acid ester 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 isolating the polyamic acid ester contained in the reaction solution, or the isolated polyamic acid ester You may use for preparation of a liquid crystal aligning agent, after refine | purifying. Isolation and purification of the polyamic acid ester can be performed according to a known method.

The polyamic acid ester synthesized as described above may be synthesized with a compound capable of reacting with the amino group at the terminal of the polymer to synthesize a terminal-modified polymer. Examples of such terminal modifiers include chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, isoxazole-5-carboxylic acid chloride, and 2-furoyl chloride.
The reaction between the polyamic acid ester and the terminal modifier can be carried out in an organic solvent, preferably in the presence of a base. The ratio of the terminal modifier used at this time is preferably 0.005 to 0.6 mol, more preferably 0.01 to 0.2 mol, relative to 1 mol of the diamine used in the reaction. . As the base, for example, tertiary amines such as pyridine and triethylamine can be preferably used. As the organic solvent, the description of the organic solvent that can be used for the synthesis of the polyamic acid can be applied. For example, N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone and the like are preferably used. be able to.

The polyamic acid ester contained in the liquid crystal aligning agent of the present invention may have only the repeating unit represented by the above formula (1) (hereinafter, also referred to as “amic acid ester structure”), or A partially esterified product containing at least one of an amic acid structure and an imide ring structure in a part of all repeating units of the polyamic acid ester may be used.
The polyamic acid ester has a repeating unit represented by the above formula (1) in an amount of 1 mol% or more based on the total repeating units of the polyamic acid ester from the viewpoint of bezel unevenness resistance which is an object of the present invention. It is preferably 5 mol% or more, more preferably 10 mol% or more. In addition, the upper limit of the content of the repeating unit represented by the above formula (1) is preferably 99 mol% or less, and more preferably 95 mol% or less from the viewpoint of rubbing resistance and heat resistance.

<Polyimide>
The polyimide contained in the liquid crystal aligning agent of the present invention can be obtained, for example, by dehydrating and ring-closing and imidizing the 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 contained in the liquid crystal aligning agent of the present invention has an imidization ratio of 75% or less from the viewpoint of improving the surface smoothness of the liquid crystal aligning film and reducing display unevenness around the sealing agent in the liquid crystal display element. Yes, preferably 70% or less, more preferably 65% or less. In addition, the lower limit of the imidization rate is preferably 1% or more, more preferably 3% or more, and more preferably 5% or more from the viewpoint of improving electrical characteristics, heat resistance, and afterimage characteristics. Is more preferable. 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.

  When the liquid crystal aligning agent of the present invention is used for photo-alignment, a part or all of the polyimide contained in the liquid crystal aligning agent may be a polymer having a photo-alignment structure. Here, the photo-alignment structure is a concept including both a photo-alignment group and a decomposition type photo-alignment part. Specifically, as the photo-alignment structure, groups derived from various compounds exhibiting photo-alignment by photoisomerization, photodimerization, photolysis, etc. can be employed. For example, azobenzene or a derivative thereof is used as a basic skeleton. Contains azobenzene-containing group, group having cinnamic acid structure containing cinnamic acid or derivative thereof as basic skeleton, chalcone-containing group containing chalcone or derivative thereof as basic skeleton, containing benzophenone or derivative thereof as basic skeleton And a coumarin-containing group containing a group, coumarin or a derivative thereof as a basic skeleton, and a polyimide-containing structure containing a polyimide or a derivative thereof as a basic skeleton.

When a polyimide having a photo-alignment structure is used, the polyimide is preferably a polymer including a decomposition-type photo-alignment part, specifically, a polyimide having a bicyclo [2.2.2] octene skeleton or a cyclobutane skeleton. It is preferable that The polyimide having these skeletons is, for example, at least one of cyclobutanetetracarboxylic dianhydride and bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride. It can be obtained by reacting a tetracarboxylic dianhydride containing a diamine.
When the liquid crystal alignment ability is imparted to the coating film by the photo-alignment method, the use ratio of the polyimide having the photo-alignment structure is preferably 10% by weight or more with respect to the total amount of the polymer component of the liquid crystal aligning agent. 30 to 97% by weight, more preferably 50 to 95% by weight.

  In addition, when providing a liquid crystal aligning ability to a coating film by the photo-alignment method, you may contain the polyamic acid ester which has a photo-alignment structure in a liquid crystal aligning agent. In this case, the total of the polyamic acid ester having a photo-alignment structure and the polyimide having the photo-alignment structure is preferably 10% by weight or more based on the total amount of the polymer component of the liquid crystal aligning agent, and 30% by weight. % Or more, more preferably 50% by weight or more.

  The dehydrating ring closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid, or a method of adding a dehydrating agent and a dehydrating ring closing catalyst to a polyamic acid solution dissolved in an organic solvent, and heating 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 for the dehydration ring-closing reaction include organic solvents 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.

  The polyamic acid ester and polyimide obtained as described above preferably have a solution viscosity of 15 to 1500 mPa · s, and preferably 20 to 1200 mPa · s. More preferably, it has a solution viscosity. In addition, the solution viscosity (mPa · s) of the above polymer is based on a polymer solution having a concentration of 15% by weight prepared using a good solvent for the polymer (eg, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The value measured at 25 ° C. using an E-type rotational viscometer.

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

  The content ratio of the polyamic acid ester and the polyimide in the liquid crystal aligning agent of the present invention is preferably 3/97 to 97/3 in a weight ratio of polyamic acid ester / polyimide. When the content ratio of polyimide is too small, the voltage holding ratio tends to be low, and when the content ratio of polyimide is too large, surface unevenness of the liquid crystal alignment film tends to occur. More preferably, it is 5 / 95-95 / 5, More preferably, it is 10 / 90-90 / 10.

<Other ingredients>
The liquid crystal aligning agent of the present invention contains the polyamic acid ester and polyimide as described above, but may contain other components as necessary. Other components that may be added to the liquid crystal aligning agent include, for example, other polymers other than polyamic acid ester and polyimide, compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy group-containing compound”) And a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, and the like.

[Other polymers]
The above other polymers can be used for improving solution properties and electrical properties. Examples of such other polymers include polyamic acid, polyester, polyamide, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. Among these, it is preferably at least one polymer selected from the group consisting of polyamic acid, polyester, polyorganosiloxane and poly (meth) acrylate, and at least one selected from the group consisting of polyamic acid and polyorganosiloxane. More preferably.

Moreover, when using the liquid crystal aligning agent of this invention for photo-alignment, you may use the polymer which has a photo-alignment structure as said other polymer. Specifically, a polymer having a photoalignable group is preferable, and a polymer into which a group having a cinnamic acid structure is introduced as the photoalignable group is more preferable. Among them, a polyorganosiloxane having a cinnamic acid structure can be preferably used because it is easy to introduce a photoalignable group into the polymer.
The polymer having a photoalignable group can be synthesized by a conventionally known method. For example, the polyorganosiloxane having a photoalignable group as another polymer is a polyorganosiloxane having an epoxy group and a carboxylic acid having a photoalignable group, preferably an organic solvent such as ether, ester, ketone, etc. It can synthesize | combine by making it react in presence of catalysts, such as a quaternary ammonium salt.

  When the other polymer is added to the liquid crystal aligning agent, the blending ratio is preferably 50 parts by weight or less with respect to 100 parts by weight of the total polymer in the composition, and 0.1 to 40 parts by weight. More preferably, it is more preferably 0.1 to 30 parts by weight.

[Epoxy group-containing compound]
The epoxy group-containing compound can be used to improve the adhesion of the liquid crystal alignment film to the substrate surface. Here, 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′-diaminodi Preferred examples include phenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexylamine, and epoxy group-containing polyorganosiloxane described in WO2009 / 096598. Can be mentioned.
When these epoxy group-containing compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 40 parts by weight or less, based on the total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent. Part is more preferred.

[Functional silane compounds]
The said functional silane compound can be used in order to improve the printability of a liquid crystal aligning agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4 , 7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, methyl 9-triethoxysilyl-3,6-diazananoate, N -Benzyl-3-aminopropy Trimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltrimethoxy A silane etc. can be mentioned.
When adding a functional silane compound to a liquid crystal aligning agent, the compounding ratio is preferably 2 parts by weight or less, and more preferably 0.02 to 0.2 parts by weight with respect to a total of 100 parts by weight of the polymer.

[Metal chelate compounds]
When the polymer component of the liquid crystal aligning agent has an epoxy structure, the metal chelate compound is a liquid crystal aligning agent (particularly a liquid crystal for a retardation film) for the purpose of ensuring the mechanical strength of the film formed by low-temperature treatment. Contained in the alignment agent). As the metal chelate compound, it is preferable to use an acetylacetone complex or acetoacetic acid complex of a metal selected from aluminum, titanium and zirconium. Specifically, for example, diisopropoxyethyl acetoacetate aluminum, tris (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, diisopropoxybis (ethylacetoacetate) titanium, diisopropoxybis (acetylacetonate) Examples thereof include titanium, tri-n-butoxyethyl acetoacetate zirconium, and di-n-butoxybis (ethyl acetoacetate) zirconium.
The proportion of the metal chelate compound used is preferably 50 parts by weight or less, more preferably 0.1 to 40 parts by weight, and 1 to 30 parts by weight with respect to 100 parts by weight of the total components including the epoxy structure. More preferably.

[Curing accelerator]
When the polymer component in the liquid crystal aligning agent has an epoxy structure, the curing accelerator is a liquid crystal in order to ensure the mechanical strength of the liquid crystal alignment film to be formed and the stability over time of the liquid crystal alignment. It is contained in an aligning agent (particularly, a liquid crystal aligning agent for a retardation film). As the curing accelerator, for example, a compound having a phenol group, a silanol group, a thiol group, a phosphoric acid group, a sulfonic acid group, a carboxyl group, a carboxylic anhydride group, or the like can be used. A compound having is preferred. Specific examples thereof include compounds having a phenol group such as cyanophenol, nitrophenol, methoxyphenoxyphenol, thiophenoxyphenol, 4-benzylphenol; compounds having a silanol group such as trimethylsilanol, triethylsilanol, 1 , 1,3,3-tetraphenyl-1,3-disiloxanediol, 1,4-bis (hydroxydimethylsilyl) benzene, triphenylsilanol, tri (p-tolyl) silanol, diphenylsilanediol, etc. be able to.
The use ratio of the curing accelerator is preferably 50 parts by weight or less, more preferably 0.1 to 40 parts by weight, and 1 to 30 parts by weight with respect to a total of 100 parts by weight of the components including the epoxy structure. More preferably.

[Surfactant]
The surfactant can be contained in a liquid crystal aligning agent (particularly, a liquid crystal aligning agent for a retardation film) for the purpose of improving the applicability of the liquid crystal aligning agent to the substrate. Examples of such surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, polyalkylene oxide surfactants, and fluorine-containing surfactants. be able to.
The proportion of the surfactant used is preferably 10 parts by weight or less, and more preferably 1 part by weight or less with respect to 100 parts by weight of the total amount of the liquid crystal aligning agent.

  In addition, an antioxidant such as a phenolic antioxidant or an amine antioxidant; a polyfunctional (meth) acrylate such as ethylene glycol diacrylate or 1,6-hexanediol diacrylate; May be.

<Solvent>
The liquid crystal aligning agent of the present invention is prepared as a liquid composition in which the above polyamic acid ester, polyimide and other components used as necessary are preferably dispersed or dissolved in an appropriate solvent.

  Examples of the solvent to be used include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, 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, etc. Can be mentioned. These can be used individually by 1 type or in mixture of 2 or more types.

  The solid content concentration in the liquid crystal aligning agent of the present invention (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, and the like. The range is preferably 1 to 10% by weight. That is, the liquid crystal aligning agent of this invention is apply | coated to a substrate surface so that it may mention later, Preferably the coating film which becomes a liquid crystal aligning film or a coating film used as a liquid crystal aligning film is formed by heating. 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 concentration varies depending on the use of the liquid crystal alignment film and the method used when applying the liquid crystal aligning agent to the substrate. For example, for a liquid crystal aligning agent for a liquid crystal cell, when applied to a substrate by a spinner method, 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 A range of 1.5 to 4.5% by weight is particularly preferable. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 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 at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC. Moreover, about the liquid crystal aligning agent for retardation films, the solid content density | concentration of a liquid crystal aligning agent is 0.2 to 10 weight% from a viewpoint which makes the applicability | paintability of a liquid crystal aligning agent, and the film thickness of the coating film formed moderate. It is preferable that it is the range of 3-10 weight%.

  Here, it is known that polyamic acid esters generally have a high volume resistivity, and there is a tendency that residual charges increase when a DC voltage is applied. In order to alleviate the DC residual charge, the polymer component of the liquid crystal aligning agent may be a blend of polyamic acid ester and polyamic acid. In such a case, display unevenness occurs around the sealing agent in the liquid crystal display element. It became clear from the examination result of the present inventors that it becomes easy. The reason for this is not necessarily clear, but it was speculated that the impurity ions from the sealing agent are adsorbed on the residual carboxyl groups derived from the polyamic acid. And based on such inference, we studied earnestly how to blend the polymer component of the liquid crystal aligning agent, and in the blend system of polyamic acid ester and polyimide having a specific range of imidization rate, a sealing agent for liquid crystal display elements It has been found that display unevenness in the periphery is suppressed.

<Liquid crystal display element and retardation film>
By using the liquid crystal aligning agent of the present invention described above, a liquid crystal aligning film can be produced. Moreover, the liquid crystal aligning film formed using the liquid crystal aligning agent of this invention is preferably applicable to the liquid crystal aligning film for liquid crystal display elements (for liquid crystal cells), and the liquid crystal aligning film for retardation films. Below, the liquid crystal display element and retardation film of this invention are demonstrated.

[Liquid crystal display element]
The liquid crystal display element of 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 of 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 the operation mode. The liquid crystal display element of this invention can be manufactured according to the process including 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 of the present invention is preferably applied by an offset printing method, a spin coating method, a roll coater method or an ink jet printing method, respectively. 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 the transparent conductive film provided on one surface of the substrate, 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 ), 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. The liquid crystal aligning agent of this invention is each apply | coated to one surface of the counter substrate which is not formed, Then, a coating film is formed by heating each application surface. 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 forming the coating film, the polyamic acid ester and polyimide compounded in the liquid crystal aligning agent of the present invention, and the polyamic acid compounded as necessary, proceed with the dehydration ring-closing reaction, and more imidized. A coated film may be used.

[Step (1-2): Orientation ability imparting treatment]
When manufacturing a TN type, STN type, IPS type, or FFS type liquid crystal display element, as a treatment for imparting liquid crystal alignment ability to the coating film formed in the above step (1-1), the coating film is made of, for example, nylon or rayon. A rubbing process is carried out by rubbing in a certain direction with a roll wound with a cloth made of fibers such as cotton. Thereby, the orientation ability of a liquid crystal molecule is provided to a coating film, and it becomes a liquid crystal aligning film. 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 a liquid crystal alignment film as it is, but even if the coating film is rubbed. Good. For the liquid crystal alignment film after the rubbing treatment, 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 light, 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. 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. As a process for imparting liquid crystal alignment ability to the coating film, a process by a photo-alignment method may be employed instead of the rubbing process.

[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 can be manufactured by injecting and filling liquid crystal into the cell gap partitioned by the step, and then 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 film faces, 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. can do. 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 a sealing agent, what is normally used as an adhesive agent for liquid crystals can be used, for example, an epoxy resin containing a curing agent can be used. Moreover, you may use as a sealing agent what further contains the aluminum oxide sphere as a spacer.
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 of 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.

[Phase difference film]
Next, a method for producing a retardation film using the liquid crystal aligning agent of the present invention will be described. In the production of the retardation film of the present invention, it is possible to form a uniform liquid crystal alignment film while suppressing the generation of dust and static electricity during the process, and an appropriate photomask is used during radiation irradiation. It is preferable to use the photo-alignment method in that a plurality of regions having different liquid crystal alignment directions can be arbitrarily formed on the substrate. Specifically, it can be produced through the following steps (2-1) to (2-3).

[Step (2-1): Formation of coating film by liquid crystal aligning agent]
First, the liquid crystal aligning agent of this invention is apply | coated on a board | substrate, and a coating film is formed. As the substrate used here, a transparent substrate made of a synthetic resin such as triacetyl cellulose (TAC), polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polyamide, polyimide, polymethyl methacrylate, polycarbonate, etc. is preferably exemplified. Can do. Of these, TAC is generally used as a protective layer for a polarizing film in a liquid crystal display device. In addition, polymethyl methacrylate can be preferably used as a substrate for a retardation film in that the hygroscopicity of the solvent is low, the optical properties are good, and the cost is low. In addition, for the substrate used for the application of the liquid crystal aligning agent, in order to further improve the adhesion between the substrate surface and the coating film, a conventionally known pretreatment is performed on the surface of the substrate surface on which the coating film is formed. May be implemented.

  In many cases, the retardation film is used in combination with a polarizing film. At this time, it is necessary to attach the retardation film by precisely controlling the angle with respect to the polarization axis of the polarizing film in a specific direction so that the desired optical characteristics can be exhibited. Accordingly, by forming a liquid crystal alignment film having a liquid crystal alignment ability in a predetermined angle direction on a substrate such as a TAC film or polymethyl methacrylate, the angle of the retardation film is controlled on the polarizing film. The step of bonding can be omitted. Thereby, it can contribute to the improvement of productivity of a liquid crystal display element. In order to form a liquid crystal alignment film having a liquid crystal alignment ability in a direction of a predetermined angle, it is preferable to carry out by a photo alignment method using the liquid crystal aligning agent of the present invention.

The liquid crystal aligning agent can be applied onto the substrate by an appropriate application method such as a roll coater method, a spinner method, a printing method, an ink jet method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber. Doctor coater method, offset gravure coater method, single roll kiss coater method, reverse kiss coater method using small diameter gravure roll, 3 reverse roll coater method, 4 reverse roll coater method, slot die method, air doctor coater method A positive rotation roll coater method, a blade coater method, a knife coater method, an impregnation coater method, an MB coater method, an MB reverse coater method, and the like can be employed.
After coating, the coated surface is heated (baked) to form a coating film. The heating temperature at this time is preferably 40 to 150 ° C, more preferably 80 to 140 ° C. The heating time is preferably 0.1 to 15 minutes, and more preferably 1 to 10 minutes. The film thickness of the coating film formed on the substrate is preferably 1 to 1,000 nm, more preferably 5 nm to 500 nm.

[Step (2-2): Light irradiation step]
Next, the coating film formed on the substrate as described above is irradiated with light, thereby imparting liquid crystal alignment ability to the liquid crystal alignment film. Here, examples of the light to be irradiated include ultraviolet rays and visible rays including light having a wavelength of 150 to 800 nm. Among these, ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. Irradiation light may be polarized or non-polarized. As the polarized light, it is preferable to use light including linearly polarized light.
When the light to be used is polarized light, the light irradiation may be performed from a direction perpendicular to the substrate surface, an oblique direction, or a combination thereof. When irradiating non-polarized light, it is necessary to carry out from a direction oblique to the substrate surface.
Examples of the light source used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and a mercury-xenon lamp (Hg-Xe lamp). Polarized light can be obtained by means of using these light sources in combination with, for example, a filter or a diffraction grating.
The dose of light is preferably set to 0.1 mJ / cm ² or more 1,000 mJ / cm less than ^2, more preferably, to 1 to 500 mJ / cm ^2, further be 2~200mJ / cm ² preferable.

[Step (2-3): Formation of Liquid Crystal Layer]
Next, a polymerizable liquid crystal is applied and cured on the coating film after the light irradiation as described above. Thereby, the coating film (liquid crystal layer) containing a polymerizable liquid crystal is formed. The polymerizable liquid crystal used here is a liquid crystal compound or a liquid crystal composition that is polymerized by at least one treatment of heating and light irradiation. As such a polymerizable liquid crystal, a conventionally known liquid crystal can be used. Specifically, for example, Non-Patent Document 1 ("UV curable liquid crystal and its application", Liquid Crystal, Vol. 3, No. 1 (1999). Year), pp 34-42). Further, cholesteric liquid crystal; discotic liquid crystal; twisted nematic alignment type liquid crystal to which a chiral agent is added may be used. The polymerizable liquid crystal may be a mixture of a plurality of liquid crystal compounds. The polymerizable liquid crystal may further be a composition containing a known polymerization initiator, an appropriate solvent, and the like.
In order to apply the polymerizable liquid crystal as described above on the formed liquid crystal alignment film, for example, an appropriate application method such as a bar coater method, a roll coater method, a spinner method, a printing method, or an ink jet method can be employed. .

Next, the coating film of the polymerizable liquid crystal formed as described above is subjected to at least one treatment selected from heating and light irradiation to cure the coating film to form a liquid crystal layer. It is preferable to perform these treatments in a superimposed manner because good alignment can be obtained.
The heating temperature of the coating film is appropriately selected depending on the type of polymerizable liquid crystal used. For example, when using RMS03-013C manufactured by Merck, it is preferable to heat at a temperature in the range of 40 to 80 ° C. The heating time is preferably 0.5 to 5 minutes.
As irradiation light, non-polarized ultraviolet rays having a wavelength in the range of 200 to 500 nm can be preferably used. The irradiation dose of light, preferably in the 50~10,000mJ / cm ^2, and more preferably a 100~5,000mJ / cm ^2.
The thickness of the liquid crystal layer to be formed is appropriately set depending on desired optical characteristics. For example, when manufacturing a half-wave plate for visible light having a wavelength of 540 nm, a thickness is selected such that the retardation of the formed retardation film is 240 to 300 nm. The thickness is selected such that the phase difference is 120 to 150 nm. The thickness of the liquid crystal layer from which the desired retardation is obtained varies depending on the optical characteristics of the polymerizable liquid crystal used. For example, when RMS03-013C manufactured by Merck is used, the thickness for manufacturing a quarter-wave plate is in the range of 0.6 to 1.5 μm.

  The retardation film obtained as described above can be preferably applied as a retardation film of a liquid crystal display element. The liquid crystal display element to which the retardation film manufactured using the liquid crystal aligning agent of the present invention is applied is not limited in its operation mode. For example, TN type, STN type, IPS type, FFS type, VA type and the like are known. It can be applied to various modes. The retardation film is used by attaching the substrate-side surface of the retardation film to the outer surface of the polarizing plate disposed on the viewing side of the liquid crystal display element. Therefore, it is preferable that the retardation film substrate is made of TAC or an acrylic base, and the retardation film substrate also functions as a protective film for the polarizing film.

  Here, there is a roll-to-roll method as a method for producing a retardation film on an industrial scale. In this method, a film is unwound from a wound body of a long base film, a liquid crystal alignment film is formed on the unwound film, and a polymerizable liquid crystal is applied and cured on the liquid crystal alignment film. It is the method of performing the process and the process which laminates | stacks a protective film as needed in the continuous process, and collect | recovering the film after passing through these processes as a wound body. The retardation film formed using the liquid crystal aligning agent of the present invention has good adhesion to the substrate, and the liquid crystal alignment film and the substrate are hardly peeled even when stored as a wound body. Therefore, it is possible to suppress a decrease in product yield when the retardation film is manufactured by the roll-to-roll method.

  The liquid crystal display element of 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, The present invention can be used for 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.

The weight average molecular weight of the polymer in the synthesis example, the imidization ratio of the polyimide, and the solution viscosity of each polymer solution were measured by the following methods.
[Weight average molecular weight of polymer]
The weight average molecular weight Mw of the polymer is a polystyrene equivalent value measured by gel permeation chromatography under the following conditions.
Column: Tosoh Co., Ltd., TSKgelGRCXLII
Solvent: Tetrahydrofuran or N, N-dimethylformamide solution containing lithium bromide and phosphoric acid Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Imidation rate of polyimide]
A solution containing polyimide is poured into pure water, and the resulting precipitate is sufficiently dried at room temperature under reduced pressure, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR is measured at room temperature using tetramethylsilane as a reference substance. did. From the obtained ¹ H-NMR spectrum, the imidation ratio [%] was determined using 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 15% by weight using a predetermined solvent.

<Synthesis of polyamic acid ester>
[Synthesis Example 1-1; Synthesis of Polymer (A-1)]
6.92 g of paraphenylenediamine (80 mol parts relative to 100 mol parts of the total amount of diamine compounds used in the synthesis) and 3.17 g of 4,4′-diaminodiphenylmethane (20 mol parts) as a diamine compound, as a base 15 ml of pyridine and 505 ml of N-methyl-2-pyrrolidone (NMP) as a solvent were added and dissolved. While stirring this solution with water, 2.975 g (97 mol parts) of dimethyl-1,3-bis (chlorocarbonyl) cyclobutane-2,4-carboxylate was added, and the solid content concentration became 5% by weight. NMP was added so that the mixture was stirred for 4 hours while cooling with water. This solution is poured into 250 g of water to precipitate a polymer, and the polymer is collected by suction filtration, washed again with 250 g of water, then washed 3 times with 63 g of methanol, and dried under reduced pressure at 40 ° C. 28 g of polyamic acid ester powder of the polymer (A-1) was obtained. The weight average molecular weight of this polyamic acid ester was Mw = 27,000. The obtained polymer (A-1) was prepared so that it might become 15 weight% with NMP.

[Synthesis Example 1-2; Synthesis of Polymer (A-2)]
Add 2.00 g (10.0878 mol) of 4,4′-diaminodiphenylmethane as a diamine compound, 40.94 g of N-methyl-2-pyrrolidone, and 1.9246 g (24.3317 mol) of pyridine as a base, and dissolve by stirring. It was. Next, 3.0831 g (9.4825 mol) of dimethyl-1,3-bis (chlorocarbonyl) cyclobutane-2,4-carboxylate was added while stirring the diamine solution, and the mixture was reacted for 4 hours under water cooling. Thereafter, 0.1725 g (1.3114 mol) of isoxazole-5-carboxylic acid chloride was added and reacted for 30 minutes under water cooling. Thereafter, 45.06 g of N-methyl-2-pyrrolidone was added to the reaction solution, and the mixture was stirred at room temperature (20 ° C.) for 15 minutes. The obtained polyamic acid ester solution was poured into 495 g of ethanol while stirring, and the precipitated white precipitate was collected by filtration. Subsequently, it was washed once with 226 g of ethanol, twice with 451 g of water, once with 451 g of ethanol, three times with 113 g of ethanol, and dried to give 4 g of polyamic acid ester powder of polymer (A-2) Got. Moreover, the weight average molecular weight of this polyamic acid ester was Mw = 18,000. The obtained polymer (A-2) was prepared so that it might become 15 weight% with NMP.

<Synthesis of polyimide>
[Synthesis Example 2-1; Synthesis of Polymer (BIm-1)]
As tetracarboxylic dianhydride, 2,2,3,4-cyclobutanetetracarboxylic dianhydride 24.764 g (98 mol parts relative to 100 mol parts of the total amount of diamine compounds used in the synthesis), and as diamine compounds 2.786 g (20 mole parts) of paraphenylenediamine, 10.219 g (40 mole parts) of 4,4′-diaminodiphenylamine, and 12.231 g (40 mole parts of the compound represented by the following formula (DA-8)) ) Was dissolved in 200 g of NMP and reacted at room temperature for 6 hours. Next, 250 g of NMP was added, and 2.00 g of pyridine (20 mol parts relative to a total of 100 mol parts of acid dianhydride) and 2.58 g of acetic anhydride (20 mol parts) were added and dehydrated at 70 ° C. for 6 hours. A ring closure reaction was performed. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. The recovered precipitate was washed with methanol, and then dried at 40 ° C. under reduced pressure for 15 hours to obtain a polyimide having an imidation ratio of about 10% (hereinafter referred to as “polymer (BIm-1)”). The obtained polymer (BIm-1) was prepared so that it might become 15 weight% with NMP. The viscosity of this solution was measured and found to be 502 mPa · s.

[Synthesis Example 2-2 to Synthesis Example 2-10]
In Synthesis Example 2-1, the types and amounts of tetracarboxylic dianhydride and diamine compound used in the reaction, and the amounts of pyridine and acetic anhydride were changed as shown in Table 1 below. Thus, polyimide was synthesized to obtain a polymer (BIm-2) to a polymer (BIm-10). In addition, the numerical value of Table 1 shows the use ratio (mol%) with respect to the whole quantity of the tetracarboxylic dianhydride used for reaction about the tetracarboxylic dianhydride, It used for reaction about the diamine compound. The use ratio (mol%) with respect to the whole quantity of a diamine compound is shown. About pyridine and acetic anhydride, the molar part with respect to a total of 100 molar parts of tetracarboxylic dianhydride is shown. When each of the polymer solutions obtained in Synthesis Example 2-1 to Synthesis Example 2-10 was allowed to stand at 20 ° C. for 3 days, none of them was gelled, and the storage stability was good.

In Table 1, the abbreviations of the compounds have the following meanings.
(Tetracarboxylic dianhydride)
AN-1, 1, 2,3,4-cyclobutanetetracarboxylic dianhydride AN-2; pyromellitic dianhydride AN-3; 2,3,5-tricarboxycyclopentylacetic dianhydride AN-4; Ethylenediaminetetraacetic acid dianhydride AN-5; 5- (2,5-dioxotetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1 , 3-dione AN-6; bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-dianhydride (diamine)
DA-1; paraphenylenediamine DA-2; 4,4′-diaminodiphenylmethane DA-3; 4-aminophenyl-4′-aminobenzoate DA-4; 4,4 ′-[4,4′-propane-1 , 3-Diylbis (piperidine-1,4-diyl)] dianiline DA-5; 2,4-diamino-N, N-diallylaniline DA-6; 4,4′-diaminodiphenylamine DA-7; Diaminobenzoic acid DA-8; compound DA-9 represented by the above formula (DA-8); 1,5-bis (4-aminophenoxy) pentane DA-10; 4- (tetradecaoxy) benzene-1, 3-diamine DA-11; cholestanyl 3,5-diaminobenzoate

<Synthesis of polyamic acid>
[Synthesis Example 3-1; Synthesis of Polymer (BAm-1)]
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 2.4301 g (15.97 mmol) of 3,5-diaminobenzoic acid, 4,4 ′-[4,4′-propane-1,3- Diylbis (piperidine-1,4-diyl)] dianiline (9.4204 g, 24.0 mmol) was taken, 44.60 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 4.7505 g (23.98 mmol) of 1,2,3,4-butanetetracarboxylic dianhydride was added and stirred at room temperature for 2 hours. Next, 44.59 g of NMP was added, and 3.1054 g (15.84 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was added. Further, NMP was added so that the solid content concentration was 15% by weight, and the mixture was stirred at room temperature for 24 hours. The resulting polyamic acid had a viscosity of 802 mPa · s. Further, 0.0590 g of 3-glycidylpropylmethyldiethoxysilane was added to this solution and stirred at room temperature for 24 hours to obtain a polyamic acid solution containing a polymer (BAm-1).

[Example 1-1: FFS type liquid crystal display element]
(1) Preparation of liquid crystal aligning agent As a polymer, 80 parts by weight of the polymer (A-1) obtained in Synthesis Example 1-1 and 20 parts by weight of the polymer (BIm-1) obtained in Synthesis Example 2-1. , Γ-butyrolactone (GBL), NMP and butyl cellosolve (BC) mixed solvent (GBL: NMP: BC = 40: 40: 20 (weight ratio)), a solid content concentration of 3.5 wt% solution It was. A liquid crystal aligning agent was prepared by filtering this solution through a filter having a pore size of 0.2 μm.

(2) Evaluation of surface irregularity of coating film The liquid crystal aligning agent prepared above was applied on a glass substrate using a spinner, pre-baked on a hot plate at 80 ° C. for 1 minute, and then the interior was replaced with nitrogen. By heating (post-baking) in an oven at 200 ° C. for 1 hour, a coating film having an average film thickness of 1,000 mm was formed. This coating film was observed with an atomic force microscope (AFM), and the center average roughness (Ra) was measured. In the evaluation, the surface roughness of “less than 1.0 nm” is “good”, the case of 1.0 nm or more and less than 5.0 nm is “good”, and the case of 5.0 nm or more is “bad”. In this example, Ra was 0.4 nm and the surface irregularity was “good”.

(3) Evaluation of rubbing resistance The coating film obtained above was rubbed at a roll rotation speed of 1000 rpm, a stage moving speed of 20 cm / sec, and a hair foot indentation length of 0.4 mm by a rubbing machine having a roll wrapped with a cotton cloth. The treatment was performed 7 times. Foreign matter (a piece of coating film) due to rubbing scraping on the obtained substrate was observed with an optical microscope, and the number of foreign matters in a 500 μm × 500 μm region was measured. In the evaluation, the rubbing resistance was “good” when the number of foreign substances was 3 or less, “good” when 4 or more and 7 or less were present, and the rubbing resistance “bad” when 8 or more. As a result, the rubbing resistance of this coating film was “good”.

(4) Manufacture of FFS type liquid crystal display element The FFS type liquid crystal display element 10 shown in FIG. 1 was produced. First, a glass substrate 11a having two electrode pairs on one side each having a bottom electrode 15 having no pattern, a silicon nitride film as an insulating layer 14, and a top electrode 13 patterned in a comb shape in this order. And the counter glass substrate 11b provided with no electrode, and the liquid crystal aligning agent prepared in the above (1) is applied to the surface having the transparent electrode of the glass substrate 11a and one surface of the counter glass substrate 11b, respectively. Was applied to form a coating film. Next, this coating film was pre-baked for 1 minute on a hot plate at 80 ° C., and then heated (post-baked) at 230 ° C. for 15 minutes in an oven in which the inside of the chamber was replaced with nitrogen, so that the average film thickness was 1,000 mm. A coating film was formed. A schematic plan view of the top electrode 13 is shown in FIG. 2A is a top view of the top electrode 13, and FIG. 2B is an enlarged view of a portion C1 surrounded by a broken line in FIG. 2A. In this example, the line width d1 of the electrodes was 4 μm, and the distance d2 between the electrodes was 6 μm.

  Next, a rubbing process was performed on each surface of the coating film formed on the glass substrate with cotton to obtain a liquid crystal alignment film 12. In FIG.2 (b), the rubbing direction with respect to the coating film formed on the glass substrate 11a is shown by the arrow. Next, after applying the product name “XN-21-S” (manufactured by Mitsui Chemicals) as a sealant to the outer edge of the surface having the liquid crystal alignment film in one of the pair of substrates, Then, the substrates were bonded together via a spacer having a diameter of 3.5 μm so that the rubbing directions of the substrates 11a and 11b were antiparallel, and the sealant was cured. Next, liquid crystal MLC-6221 (manufactured by Merck & Co., Inc.) was injected between the pair of substrates through the liquid crystal injection port to form the liquid crystal layer 16. Furthermore, the liquid crystal display element 10 was produced by bonding a polarizing plate (not shown) on both outer surfaces of the substrates 11a and 11b so that the polarization directions of the two polarizing plates were orthogonal to each other.

(5) Evaluation of liquid crystal alignment The presence / absence of an abnormal domain in a change in brightness when a voltage of 5 V is turned on / off (applied / released) is measured with a microscope at a magnification of 50 for the FFS type liquid crystal display device manufactured in (4) above. Observed at double. In the evaluation, when the abnormal domain was not observed, the liquid crystal alignment was “good”, and when the abnormal domain was observed, the liquid crystal alignment was “bad”. In this liquid crystal display element, the liquid crystal orientation was “good”.
(6) Evaluation of voltage holding ratio For the FFS type liquid crystal display device manufactured in the above (4), a voltage of 5 V was applied at 23 ° C. with an application time of 60 microseconds and a span of 167 milliseconds, and then 167 The voltage holding ratio (VHR) after milliseconds was measured and found to be 98.9%. In addition, as a measuring apparatus, Toyo Technica Co., Ltd. make and VHR-1 were used.

(7) per FFS type liquid crystal display device manufactured in heat-resistant evaluation above (4), to measure the voltage holding ratio similarly to the above (6), and its value as an initial VHR _{(VHR BF).} Next, the liquid crystal display element after the initial VHR measurement was left in an oven at 100 ° C. for 300 hours. Thereafter, the liquid crystal display element was left at room temperature and allowed to cool to room temperature, and then the voltage holding ratio (VHR _AF ) was measured in the same manner as described above. Moreover, the change rate (ΔVHR (%)) of the voltage holding ratio before and after the application of thermal stress was determined by the following mathematical formula (2).
ΔVHR = ((VHR _BF −VHR _AF ) ÷ VHR _BF ) × 100 (2)
Evaluation of heat resistance is “good” when the rate of change ΔVHR is less than 4%, “good” when 4% or more and less than 5%, and “high” when 5% or more. Went as "bad". As a result, ΔVHR of the liquid crystal display element of this example was 2.9%, and the heat resistance was “good”.

(8) Contrast evaluation after driving stress (AC afterimage characteristics evaluation)
An FFS type liquid crystal cell was produced by performing the same operation as in the above (4) except that the polarizing plate was not bonded to both outer surfaces of the substrate. About this FFS type liquid crystal cell, after driving for 30 hours at an AC voltage of 10 V, using a device in which a polarizer and an analyzer are arranged between a light source and a light quantity detector, the minimum relative value expressed by the following formula (3) is used. The transmittance (%) was measured.
Minimum relative transmittance (%) = (β−B ⁰ ) / (B ¹⁰⁰ −B ⁰ ) × 100 (3)
(In Formula (3), B ⁰ is the transmission amount of light under a crossed Nicol in a blank. B ¹⁰⁰ is the transmission amount of light under a Paranicol in a blank. Β is a polarizer under a crossed Nicol. (This is the minimum light transmission amount with the liquid crystal display element sandwiched between the analyzers.)
The black level in the dark state is expressed by the minimum relative transmittance of the liquid crystal display element. In the FFS type liquid crystal display element, the smaller the black level in the dark state, the better the contrast. A sample having a minimum relative transmittance of less than 0.5% was evaluated as “good”, a sample having a minimum relative transmittance of less than 0.5% and less than 1.0% was evaluated as “good”, and a sample having a minimum relative transmittance of 1.0% or more was determined as “bad”. As a result, the minimum relative transmittance of this liquid crystal display element was 0.2%, which was judged as “good”.

(9) Unevenness around sealant (bezel unevenness resistance)
The FFS type liquid crystal display device manufactured in (4) above was stored for 100 days under the conditions of 25 ° C. and 50% RH, and then driven with an AC voltage of 5 V to observe the lighting state. The evaluation is “excellent” if the luminance difference (more black or more white) is not visually recognized around the sealant, but is “good” if the luminance difference disappears in less than 1 minute after lighting. The case where the luminance difference disappeared in less than 10 minutes was judged “good”, and the case where the luminance difference was visually recognized even after 10 minutes passed was regarded as “bad”. As a result, the luminance difference of the liquid crystal display element was not visually recognized, and was determined to be “excellent”.

[Example 1-2 to Example 1-8 and Comparative Example 1-1 to Comparative Example 1-5]
In Example 1-1, a liquid crystal aligning agent was prepared in the same manner as in Example 1-1 except that the types shown in Table 2 below were used as the polymer, and an FFS type liquid crystal display element and liquid crystal cell were prepared. Various evaluations were made. The evaluation results are shown in Table 3 below.

As shown in Table 3, in Examples 1-1 to 1-8, good results were obtained for the surface irregularity and rubbing resistance of the coating film. Further, the evaluation of the bezel unevenness resistance of the liquid crystal display element was “excellent” or “good”. Furthermore, in Examples 1-1 to 1-8, the orientation, voltage holding ratio, heat resistance, and AC afterimage characteristics of the liquid crystal molecules in the liquid crystal display element are also “good” or “possible” results. It was found to have a good balance.
On the other hand, in Comparative Example 1-1 to Comparative Example 1-5, the bezel unevenness resistance was “OK” or “Bad”, which was inferior to the Examples. Moreover, in Comparative Example 1-1 to Comparative Example 1-4, the surface irregularity of the coating film is “Yes” or “Poor”, and in Comparative Example 1-3, the rubbing resistance of the coating film is “Yes”. In Example 1-2, the heat resistance was “bad”.

[Example 2-1: TN liquid crystal display element]
(1) Preparation of liquid crystal aligning agent As a polymer, 85 parts by weight of the polymer (A-1) obtained in Synthesis Example 1-1 and 15 parts by weight of the polymer (BIm-9) obtained in Synthesis Example 2-9 were used. And a mixed solvent of NMP and BC (NMP: BC = 50: 50 (weight ratio)) to obtain a solution having a solid content concentration of 6.5% by weight. After sufficiently stirring this solution, a liquid crystal aligning agent was prepared by filtering through a filter having a pore size of 0.2 μm.

(2) Evaluation of printability The liquid crystal aligning agent prepared in the above (1) is applied to the transparent electrode surface of the glass substrate with a transparent electrode made of an ITO film using a liquid crystal alignment film printer (Nissha Printing Co., Ltd.). Apply and heat for 1 minute on a hot plate at 80 ° C (pre-bake) to remove the solvent, then heat on a hot plate at 200 ° C for 10 minutes (post-bake) to form a coating film with an average film thickness of 600 mm did. This coating film was observed with a microscope with a magnification of 20 times to examine the presence or absence of printing unevenness and pinholes. In the evaluation, when neither printing unevenness nor pinhole was observed, the printability was “good”, and when at least one of printing unevenness and pinhole was slightly observed, printability was “good”, printing unevenness and pin The case where at least one of the holes was frequently observed was regarded as “printing failure”. In this example, neither printing unevenness nor pinholes were observed, and the printability was “good”.

(3) Manufacture of TN type liquid crystal cell Transparent electrode of glass substrate with transparent electrode made of ITO liquid crystal aligning agent prepared in (1) above using liquid crystal alignment film printer (Nissha Printing Co., Ltd.) After coating on the surface and heating (pre-baking) on a hot plate at 80 ° C. for 1 minute to remove the solvent, heating (post-baking) on a hot plate at 200 ° C. for 10 minutes to obtain a coating film with an average film thickness of 600 mm Formed. This coating film was rubbed with a rubbing machine having a roll wrapped with a rayon cloth at a roll rotation speed of 500 rpm, a stage moving speed of 3 cm / sec, and a hair foot indentation length of 0.4 mm to give liquid crystal alignment ability. . Then, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying was performed in a 100 ° C. clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film. 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 pair of substrates is aligned with the liquid crystal alignment film surface. The adhesives were cured by overlapping and pressing them so that they face each other. 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, whereby a TN liquid crystal cell is obtained. Manufactured.

(4) Evaluation of liquid crystal orientation About the liquid crystal cell manufactured by said (3), the presence or absence of the abnormal domain when the voltage of 5V was turned on / off under crossed Nicols was observed with the microscope at 50 time magnification. Evaluation was performed in the same manner as in Example 1-1 (5). As a result, this liquid crystal display element had “good” liquid crystal alignment.

(5) Evaluation of pretilt angle stability With respect to the liquid crystal cell produced in (3) above, the angle of inclination of the liquid crystal molecules from the substrate surface was measured by a crystal rotation method using He—Ne laser light, and this value was used as the initial pretilt. The angle was θ _IN . Non-Patent Document 1 (TJScheffer et.al., J. Appl. Phys. Vol. 48, p1783 (1977)) and Non-Patent Document 2 (F. Nakano et.al., JPN. J. Appl). Phys. Vol. 19, p2013 (1980)).
Then, the liquid crystal display device was measured for initial pretilt angle theta _IN, and the alternating voltage of 5V was applied for 100 hours. Thereafter, the pretilt angle was measured again by the same method as described above, and this value was defined as the pretilt angle θ _AF after voltage application. By substituting these measured values into the following formula (4), the amount of change in the pretilt angle (Δθ (°)) before and after voltage application was determined.
Δθ = | θ _AF −θ _IN | (4)
Pretilt angle stability is “good” when Δθ is less than 3%, pretilt angle stability is “good” when it is 3% or more and less than 4%, and pretilt angle stability is when it is 4% or more. As a result of evaluation as “defective”, the pretilt angle change rate of this liquid crystal display element was 2.7%, and it was judged that the pretilt angle stability was “good”.

(6) Evaluation of voltage holding ratio and heat resistance The voltage holding ratio (VHR _BF ) was measured in the same manner as (6) in Example 1-1, and the same as (7) in Example 1-1. Thus, the heat resistance of the liquid crystal display element was evaluated based on the change rate of the voltage holding ratio before and after application of thermal stress. As a result, VHR _BF was 99.1%. Further, ΔVHR was 2.2%, and the heat resistance was judged as “good”.
(7) Unevenness around sealant (bezel unevenness resistance)
The bezel unevenness resistance was evaluated in the same manner as in Example 1-1 (9). As a result, the luminance difference of the liquid crystal display element was not visually recognized, and was determined to be “excellent”.

[Example 3-1: VA liquid crystal display element]
(1) Preparation of liquid crystal aligning agent As polymers, 20 parts by weight of the polymer (A-1) obtained in Synthesis Example 1-1 and 80 parts by weight of the polymer (BIm-10) obtained in Synthesis Example 2-10 NMP and BC were added to obtain a solution having a solid concentration of 6.5% by weight and a solvent mixing ratio of NMP: BC = 50: 50 (weight ratio). After sufficiently stirring this solution, a liquid crystal aligning agent was prepared by filtering with a filter having a pore size of 0.2 μm.

(2) Evaluation of printability Using the liquid crystal aligning agent prepared in (1) above, the printability was examined in the same manner as in Example 2-1 (2). It was not observed and the printability was “good”.

(3) Manufacture of VA type liquid crystal cell The liquid crystal aligning agent prepared above is liquid crystal aligning film printer (Nissha Printing Co., Ltd.) on the transparent electrode surface of a glass substrate with a transparent electrode (thickness 1 mm) made of ITO film. )), And heated (pre-baked) for 1 minute on a hot plate at 80 ° C. and further heated (post-baked) for 60 minutes on a hot plate at 200 ° C. 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 liquid crystal orientation, voltage holding ratio, and heat resistance The liquid crystal cell manufactured in (3) above was evaluated for liquid crystal orientation in the same manner as in Example 1-1 (5). The liquid crystal alignment of the display element was “good”. Further, the voltage holding ratio (VHR _BF ) is measured in the same manner as (6) in Example 1-1, and the heat resistance (voltage before and after applying thermal stress) is measured in the same manner as (7) in Example 1-1. The rate of change in retention was evaluated. As a result, VHR _BF was 99.1%. Further, ΔVHR was 2.3%, and the heat resistance was judged as “good”.

(5) Uneven resistance around the sealant (bezel unevenness resistance)
The bezel unevenness resistance was evaluated in the same manner as in Example 1-1 (9). As a result, the luminance difference of the liquid crystal display element was not visually recognized, and was determined to be “excellent”.

[Example 4-1: retardation film]
(1) Preparation of Liquid Crystal Alignment Agent As a polymer, 100 parts by weight of the polymer (A-1) obtained in Synthesis Example 1-1 and 10 parts by weight of the polymer (BIm-1) obtained in Synthesis Example 2-1. Was dissolved in a mixed solvent composed of NMP and BC (NMP: BC = 50: 50 (weight ratio)) to obtain a solution having a solid concentration of 3.5% by weight. A liquid crystal aligning agent was prepared by filtering this solution through a filter having a pore size of 0.2 μm.

(2) Production of retardation film The liquid crystal aligning agent prepared above was applied to one surface of a TAC film as a substrate using a bar coater, and baked in an oven at 120 ° C for 2 minutes to have a film thickness of 100 nm. A coating film was formed. Next, the surface of the coating film was irradiated perpendicularly from the substrate normal line with polarized ultraviolet rays of 10 mJ / cm ² containing an emission line of 313 nm using a Hg—Xe lamp and a Grand Taylor prism. Next, the polymerizable liquid crystal (RMS03-013C, manufactured by Merck & Co., Inc.) was filtered through a filter having a pore size of 0.2 μm, and this polymerizable liquid crystal was applied onto the coated film after light irradiation by a bar coater. A coating film was formed. After baking for 1 minute in an oven adjusted to a temperature of 50 ° C., an unpolarized ultraviolet ray containing 365 nm emission line was irradiated at 1,000 mJ / cm ² from a direction perpendicular to the coating surface using an Hg-Xe lamp. A retardation film was produced by curing a polymerizable liquid crystal to form a liquid crystal layer.

(3) Evaluation of liquid crystal orientation About the retardation film manufactured by said (2), the presence or absence of an abnormal domain is observed by visual observation under a cross Nicol and a polarizing microscope (2.5 times magnification). Photo-alignment) was evaluated. The evaluation was that the alignment was good visually and the abnormal domain was not observed with a polarizing microscope. The liquid crystal alignment was “good”. The abnormal domain was not observed with the visual microscope, but the abnormal domain was observed with a polarizing microscope. The case where the liquid crystal orientation was “possible”, and the case where an abnormal domain was observed visually and with a polarizing microscope was regarded as “Poor”. As a result, this retardation film was evaluated as “good” for liquid crystal alignment.

(4) Adhesiveness Using the retardation film produced in (2) above, the adhesiveness of the coating film formed with the liquid crystal aligning agent to the substrate was evaluated. First, using a regular spacer with a guide, a cutter knife was used to cut from the surface on the liquid crystal layer side of the retardation film to form 10 × 10 lattice patterns. The depth of each cut was made to reach the middle of the substrate thickness from the surface of the liquid crystal layer. Next, after attaching a cellophane tape so as to cover the entire surface of the lattice pattern, the cellophane tape was peeled off. The notches in the lattice pattern after peeling were observed visually under crossed Nicols to evaluate the adhesion. The evaluation was that the adhesion was “good” when no peeling was observed at the portion along the cut line and at the intersection of the lattice pattern, and the number of lattices where peeling was observed in the above portion was the number of the entire lattice pattern. On the other hand, when the amount is less than 15%, the adhesion is “possible”, and when the number of lattices where peeling is observed in the above portion is 15% or more with respect to the total number of lattice patterns, the adhesion is “bad”. went. As a result, this retardation film had good adhesion.

  DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display element, 11a, 11b ... Glass substrate, 12 ... Liquid crystal aligning film, 13 ... Top electrode, 14 ... Insulating layer, 15 ... Bottom electrode, 16 ... Liquid crystal layer, f ... Rubbing direction.

Claims (6)

The liquid crystal aligning agent characterized by including the polyamic acid ester which has a repeating unit represented by following formula (1), and a polyimide, and the imidation ratio of this polyimide is 75% or less.

(In formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 5 carbon atoms, and R ³ and R ⁴ are each independently a hydrogen atom or a substituted or unsubstituted carbon atom having 1 to 5 carbon atoms. 10 is a monovalent chain hydrocarbon group, X ¹ is a tetravalent organic group, and Y ¹ is a divalent organic group.)   The liquid crystal aligning agent of Claim 1 whose content ratio of polyamic acid ester and a polyimide is 3/97-97/3 in the weight ratio of polyamic acid ester / polyimide. X ¹ is bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid 2: 3,5: 6-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid. Dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1 , 2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1, 3-dione, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid di Is it a group consisting of anhydride and pyromellitic dianhydride? The liquid crystal aligning agent of Claim 1 or 2 which is a structural unit derived from the at least 1 type of compound chosen from these. Ru using the liquid crystal alignment agent according to any one of claims 1 to 3, the method of manufacturing a liquid crystal alignment film. A step of forming a liquid crystal alignment film on each of a pair of substrates by the manufacturing method according to claim 4 ,
Method of manufacturing a liquid crystal display device comprising the steps of constructing a liquid crystal cell by disposing a liquid crystal between a pair of substrates, wherein the liquid crystal alignment film is formed. Applying the liquid crystal aligning agent according to any one of claims 1 to 3 on a substrate to form a coating film;
Irradiating the coating film with light;
A method of producing a retardation film, comprising: applying a polymerizable liquid crystal on the coating film after the light irradiation and curing the liquid crystal.

Images