JP2014224978A - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal alignment agent that enables production of a liquid crystal display with high reliability.SOLUTION: A liquid crystal alignment agent contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide (A), and a polyfunctional block isocyanate compound (B-1) having an aromatic ring.

Description

  The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element, and more particularly to a technique for improving the reliability of a liquid crystal display element.

  Conventionally, as a liquid crystal display element, various drive systems having different electrode structures and physical properties of liquid crystal molecules to be used have been developed. For example, TN type, STN type, VA type, MVA type, in-plane switching type (IPS type) ), FFS type, optical compensation bend type (OCB type) and other various liquid crystal display elements are known. These liquid crystal display elements have a liquid crystal alignment film for aligning liquid crystal molecules. As the material for the liquid crystal alignment film, polymers such as polyamic acid, polyimide, polyamic acid ester, polyester, and polyorganosiloxane are used. Among them, various properties such as heat resistance, mechanical strength, and affinity with liquid crystal are good. Therefore, polyamic acid and polyimide are generally used.

  In recent years, liquid crystal display elements are used not only in display devices such as personal computers as in the past, but also in various applications such as liquid crystal televisions, car navigation systems, mobile phones, smartphones, and information displays. . Further, liquid crystal display elements are required to have high reliability that can withstand long-term use, and various liquid crystal aligning agents have been proposed to satisfy such requirements (for example, Patent Documents 1 and 2). reference). Patent Documents 1 and 2 contain a polyimide having a carboxyl group as a polymer component, a primary amino group and a nitrogen-containing aromatic heterocyclic ring as an additive component, and the primary amino group is aliphatic. A liquid crystal aligning agent containing a primary amine compound bonded to a hydrocarbon group is disclosed.

International Publication No. 2008/013285 International Publication No. 2009/084665

  The demand for higher performance of liquid crystal display elements is further increasing, and as a liquid crystal alignment film, there is less deterioration / deterioration after long-term use than conventional ones, and the reliability that can suitably express the performance as a liquid crystal alignment film Higher ones are required.

  The present invention has been made in view of the above problems, and a main object thereof is to provide a liquid crystal aligning agent capable of improving the reliability of a liquid crystal display element. Another object is to provide a highly reliable liquid crystal display element.

  As a result of intensive studies to achieve the above-described problems of the prior art, the present inventors have found that the above problems can be solved by including a specific compound as an additive component in the liquid crystal aligning agent. The present invention has been completed. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element.

  In one aspect, the present invention provides at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, a polyfunctional blocked isocyanate compound (B-1) having an aromatic ring, The liquid crystal aligning agent containing is provided.

  In one aspect, the present invention provides a liquid crystal alignment film formed using the liquid crystal aligning agent described above. Furthermore, this invention provides the liquid crystal display element which comprises the said liquid crystal aligning film in another one side surface.

  According to the liquid crystal aligning agent of this invention, by containing the said compound (B-1) as an additional component, even if it uses for a long time, there is little fall of a voltage holding rate and it obtains a reliable liquid crystal display element. Can be formed.

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

<Polymer (A)>
The liquid crystal aligning agent of this invention contains at least 1 type of polymer (A) selected from the group which consists of a polyamic acid, a polyamic acid ester, and a polyimide as a polymer component.
[Polyamic acid]
The polyamic acid (hereinafter also referred to as “polyamic acid (A)”) as the polymer (A) in the present invention can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine.

(Tetracarboxylic dianhydride)
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid (A) in the present invention include, for example, an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, and an aromatic tetracarboxylic dianhydride. Things can be mentioned. Specific examples of these are:
Examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a, 4, 5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b- Hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane -2,4-dione-6-spiro-3 '-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene- No 1,2-dicarboxylic acid 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2 : 4,6: 8-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride Cyclopentanetetracarboxylic dianhydride and the like;
Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride;
In addition to the above, tetracarboxylic dianhydrides described in JP 2010-97188 A can be used. In addition, the said tetracarboxylic dianhydride can be used individually by 1 type or in combination of 2 or more types.

The tetracarboxylic dianhydride used for the synthesis of the polyamic acid (A) preferably includes an alicyclic tetracarboxylic dianhydride in terms of good solubility in a solvent and transparency. Among them, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 2-c] furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride, 1,2,4 At least selected from the group consisting of 5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride Type (hereinafter referred to as “specific Tet More preferably 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane. -2: 4,6: 8-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 1,2,3 More preferably, it contains at least one compound selected from the group consisting of 1,4-cyclopentanetetracarboxylic dianhydride (hereinafter also referred to as “specific tetracarboxylic dianhydride”).
The tetracarboxylic dianhydride used for the synthesis of polyamic acid should contain the above-mentioned specific tetracarboxylic dianhydride in an amount of 20 mol% or more based on the total amount of tetracarboxylic dianhydride used for the synthesis. Is preferable, more preferably 50 mol% or more, and even more preferably 80 mol% or more.

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

（式（Ｄ−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、ｎは０又は１である。但し、ａ及びｂが同時に０になることはない。）
で表される化合物などを； Examples of aromatic diamines include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl ] Propane, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylene Riden) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diamino Pyrimidine, 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, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, 1- (4-aminophen 2) -2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, 3,5-diaminobenzoic acid, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3, 5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, 3,5-diamino Lanostanyl benzoate, 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-di Aminobenzoate, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, , 1-bis (4-((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, 2,4-diamino-N, N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, and the following formula (D-1)

(In Formula (D-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 n is 0 or 1, provided that a and b is never 0 at the same time.)
A compound represented by:

Examples of diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane;
In addition to these, diamines described in JP 2010-97188 A can be used. As other diamine, these 1 type can be used individually or in combination of 2 or more types.

Examples of the divalent group represented by “—X ^I — (R ^I —X ^II ) _n —” in the formula (D-1) include an alkanediyl group 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 (D-1) include, for example, compounds represented by the following formulas (D-1-1) to (D-1-5).

[Molecular weight regulator]
In synthesizing 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 molecular weight regulators include acid monoanhydrides, monoamine compounds, monoisocyanate compounds, and the like. Specific examples of these acid monoanhydrides include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic acid. Nic acid anhydride, n-hexadecyl succinic acid anhydride, etc .;
Examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; examples of monoisocyanate compounds include phenyl isocyanate and naphthyl isocyanate; Each 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.

[Synthesis of polyamic acid]
The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction in the present invention is such that the acid anhydride group of the tetracarboxylic dianhydride is 0. A ratio of 2 to 2 equivalents is preferable, and a ratio of 0.3 to 1.2 equivalents is more preferable.
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 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Specific examples of these organic solvents include, for example, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N, N as the aprotic polar solvent. -Dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide and the like; as the phenolic solvent, for example, phenol, m-cresol, xylenol, halogenated phenol, etc. ;
Examples of the alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, and the like. Examples of the ketone include acetone, Examples of the ester include, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, and malon Diethyl acid, isoamyl propionate, isoamyl isobutyrate and the like;
Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether. Acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, diisopentyl ether and the like;
Examples of the halogenated hydrocarbon include dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, and the like. Examples of the hydrocarbon include hexane, heptane, octane, Benzene, toluene, xylene, etc. can be mentioned respectively.

  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 It is preferable to use a mixture with one or more selected from the group consisting of alcohol, ketone, ester, ether, halogenated hydrocarbon and hydrocarbon (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. 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. It is preferable.

  As described above, a reaction solution obtained by dissolving the polyamic acid (A) is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, and may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid (A) contained in the reaction solution, or the isolated polyamic acid. You may use for preparation of a liquid crystal aligning agent, after refine | purifying (A). When polyamic acid (A) is dehydrated and cyclized into polyimide, the above reaction solution may be subjected to dehydration and cyclization reaction as it is, and the polyamic acid (A) contained in the reaction solution is isolated and dehydrated and cyclized. You may use for reaction or after refine | purifying the isolated polyamic acid (A), you may use for dehydration ring closure reaction. Isolation and purification of the polyamic acid (A) can be performed according to a known method.

[Polyamic acid ester]
The polyamic acid ester (hereinafter also referred to as polyamic acid ester (A)) as the polymer (A) is, for example, [I] a polyamic acid (A) obtained by the above synthesis reaction, a hydroxyl group-containing compound, a halogen , A method of synthesizing by reacting an epoxy group-containing compound, [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 obtained by:
Here, examples of the hydroxyl group-containing compound used in the method [I] include alcohols such as methanol, ethanol and propanol; phenols such as phenol and cresol. Examples of the halide include methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane and the like, and as an epoxy group-containing compound, Examples thereof include propylene oxide. The tetracarboxylic acid diester used in Method [II] can be obtained, for example, by opening a ring of tetracarboxylic dianhydride using the above alcohols. The tetracarboxylic acid diester dihalide used in the method [III] can be obtained by reacting the tetracarboxylic acid diester obtained as described above with an appropriate chlorinating agent such as thionyl chloride. Examples of the diamine used in the methods [II] and [III] include a diamine used in the synthesis of the polyamic acid (A). The polyamic acid ester (A) may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.

[Polyimide]
The polyimide as the polymer (A) (hereinafter also referred to as “polyimide (A)”) can be obtained by dehydrating and ring-closing the polyamic acid (A) synthesized as described above to imidize. it can.

  The polyimide (A) may be a completely imidized product obtained by dehydrating and ring-closing all of the amic acid structure of the polyamic acid (A) as a precursor, and only a part of the amic acid structure may be dehydrating and ring-closing. Alternatively, it may be a partially imidized product in which an amic acid structure and an imide ring structure coexist. The polyimide (A) has an imidation ratio of preferably 30% or more, more preferably 50 to 99%, and still more preferably 60 to 99%. This imidation ratio represents the ratio of the number of imide ring structures to the total of the number of polyimide amic acid structures and the number of imide ring structures in percentage. Here, a part of the imide ring may be an isoimide ring.

  The dehydration ring closure of the polyamic acid (A) is preferably performed by heating the polyamic acid (A) or by dissolving the polyamic acid (A) in an organic solvent, and adding a dehydrating agent and a dehydration ring closure catalyst to this solution. Depending on the heating method. Of these, the latter method is preferred.

  In the method of adding a dehydrating agent and a dehydrating ring-closing catalyst to the polyamic acid (A) solution, as the dehydrating agent, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or 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 (A). As the dehydration ring closure catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, triethylamine and the like can be used. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of the organic solvent used for the dehydration ring-closing reaction include the organic solvents exemplified as those used for the synthesis of the polyamic acid (A). 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 the polyimide (A) is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, or 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 polyimide (A) was isolated. You may use for preparation of a liquid crystal aligning agent on the top, or you may use for preparation of a liquid crystal aligning agent, after refine | purifying the isolated polyimide (A). These purification operations can be performed according to known methods. In addition, the synthesis | combining method of polyimide (A) is not limited to the above, For example, you may carry out by imidation of polyamic acid ester (A).

The polyamic acid, the polyamic acid ester, and the polyimide as the polymer (A) obtained as described above have a solution viscosity of 10 to 800 mPa · s when this is a 10% by weight solution. It is preferable to have a solution viscosity of 15 to 500 mPa · s. In addition, the solution viscosity (mPa · s) of the polymer (A) is a concentration of 10% prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) of the polymer (A). % Of the polymer solution measured at 25 ° C. using an E-type rotational viscometer.
Further, for the polyamic acid, polyamic acid ester and polyimide as the polymer (A), the polystyrene-reduced weight average molecular weight measured by gel permeation chromatography is preferably 500 to 100,000, and 1,000. More preferably, it is ˜50,000.

（式（ｂ−１）中、Ｒ^１は、水素原子又は炭素数１〜６の１価の炭化水素基であり、Ｘ^１は、炭素数１〜３０のｎ価の有機基であり、Ｘ^２は、炭素数１〜３０の１価の有機基である。ｎは２〜６の整数である。但し、式中の複数のＲ^１は同じでも異なっていてもよく、複数のＸ^２は同じでも異なっていてもよい。） <Block isocyanate compound (B)>
Examples of the additive component include a polyfunctional blocked isocyanate compound (B) (hereinafter also simply referred to as “compound (B)”). Here, the “block isocyanate compound” is a compound which is inactive at room temperature by reacting a compound having an isocyanate group (—NCO) (isocyanate compound) with a blocking agent such as a compound having active hydrogen or an active methylene compound. Say. The “active hydrogen” refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably refers to a bond energy lower than the carbon-hydrogen bond of polymethylene.
The compound (B) may be a low molecular compound obtained by reaction of a polyfunctional isocyanate compound and a blocking agent, or a polyisocyanate obtained by polymerizing a polyfunctional isocyanate compound and a blocking agent. It may be a polymer compound obtained by reaction. The compound (B) is preferably a low molecular compound, and examples thereof include a compound represented by the following formula (b-1).

(In Formula (b-1), R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms; X ¹ is an n-valent organic group having 1 to 30 carbon atoms; ² is a monovalent organic group having 1 to 30 carbon atoms, n is an integer of 2 to 6. However, a plurality of R ¹ in the formula may be the same or different, and a plurality of X ² are Same or different.)

（式（ｂ１−１）中、Ｘ^１１は、芳香環を有するｎ価の有機基である。Ｒ^１、Ｘ^２及びｎは上記式（ｂ−１）と同義である。） The compound (B) is a polyfunctional blocked isocyanate compound (B-1) having an aromatic ring from the viewpoint of suitably obtaining the effect that the performance deterioration of the liquid crystal alignment film is unlikely to occur with long-term use. Specifically, a compound represented by the following formula (b1-1) is preferable.

(In Formula (b1-1), X ¹¹ is an n-valent organic group having an aromatic ring. R ¹ , X ² and n have the same meanings as in Formula (b-1) above.)

Examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms in R ¹ of the above formula include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Here, in the present specification, the “chain hydrocarbon group” means a hydrocarbon group composed of only a chain structure without including a cyclic structure in the main chain. 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.

Specific examples of R ¹ include a chain hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an alkyl group having 1 to 6 carbon atoms; an ethenyl group, a propenyl group, a butenyl group, etc. Examples thereof include an alkenyl group having 1 to 6 carbon atoms; an alkynyl group having 1 to 6 carbon atoms such as an ethynyl group and a propynyl group, and these may be linear or branched. Examples of the alicyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group; examples of the aromatic hydrocarbon group include a phenyl group.
Among these, R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In particular, when R ¹ is a hydrogen atom, X ² is easily removed from the compound by heat treatment, which is preferable in that the isocyanate group is easily regenerated.

Examples of the n-valent organic group having 1 to 30 carbon atoms in X ¹ include a hydrocarbon group such as a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and a carbon-carbon in the hydrocarbon group. Examples include a group in which a functional group such as —O—, —COO—, —CO—, —NHCO—, —S—, and —NH— is introduced between the bonds, and a group having a heterocyclic ring. In addition, each of these groups may have a substituent such as a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkoxy group.
Here, as the n-valent chain hydrocarbon group, for example, from an alkane having 1 to 30 carbon atoms such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, dodecane, tetradecane, icosane and the like. a group in which n hydrogen atoms have been removed; a group in which n hydrogen atoms have been removed from an alkene having 1 to 30 carbon atoms such as ethene, propene, butene, pentene, and the like; a carbon number of 1 in acetylene, methylacetylene and the like Examples thereof include groups in which n hydrogen atoms have been removed from -30 alkynes, and these may be linear or branched. Examples of the n-valent alicyclic hydrocarbon group include groups in which n hydrogen atoms have been removed from an alicyclic hydrocarbon having 3 to 30 carbon atoms such as cyclopropane, cyclopentane, cyclohexane, and methylcyclohexane. The n-valent aromatic hydrocarbon group includes, for example, n hydrogens from aromatic hydrocarbons having 5 to 30 carbon atoms such as benzene, toluene, xylene, mesitylene, ethylbenzene, biphenyl, diphenylmethane, diphenylethane, naphthalene, anthracene, etc. Examples of an n-valent group having a heterocyclic ring include an n-valent group obtained by removing n hydrogen atoms from a heterocyclic ring, a chain structure, an alicyclic hydrocarbon structure, and a heterocyclic ring. And an n-valent group consisting of a structure;
X ¹ is an n-valent group having an n-valent aromatic hydrocarbon group having 5 to 30 carbon atoms or a heterocyclic ring among the above in that the reactivity with the carboxyl group of the polymer (A) can be increased. It is preferable that the group “* —NR ¹ —CO—X ² (wherein * represents a bond to X ¹ )” in the formula (b-1) is bonded to an aromatic ring or a heterocyclic ring. Preferably it is. The aromatic ring is particularly preferably a benzene ring.

X ¹ is preferably an n-valent organic group having an aromatic ring, that is, X ^{11 from the} viewpoint that the reactivity with the carboxyl group of the polymer (A) can be increased. It is more preferably an n-valent aromatic hydrocarbon group of ˜30 or an n-valent group having an aromatic heterocyclic ring. X ¹¹ has 30 or less carbon atoms, preferably 3 to 20 carbon atoms, and more preferably 3 to 15 carbon atoms.

The n-valent aromatic hydrocarbon group having 5 to 30 carbon atoms in X ¹ and X ¹¹ is an n-valent group obtained by removing n hydrogen atoms from the ring portion of the aromatic hydrocarbon having 5 to 30 carbon atoms. It is preferable. In this case, a group obtained by removing n hydrogen atoms from the same ring or a group obtained by removing a total of n hydrogen atoms from a plurality of rings may be used.
In the n-valent group having an aromatic heterocycle in X ¹ and X ^11, the aromatic heterocycle is preferably a nitrogen-containing aromatic heterocycle having a nitrogen atom in the ring portion. Specific examples include a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, and a triazine ring, and a pyridine ring, a pyrimidine ring, or a triazine ring is more preferable. The number of aromatic heterocycles X ¹ and X ¹¹ have is not particularly limited, and may be 1 or 2 or more. The n-valent group having an aromatic heterocyclic ring is preferably an n-valent group obtained by removing n hydrogen atoms from the ring portion of the aromatic heterocyclic ring. In this case, a group obtained by removing n hydrogen atoms from the same heterocycle may be used, or a group obtained by removing a total of n hydrogen atoms from a plurality of heterocycles.

  n is preferably an integer of 2 to 4, more preferably 2 or 3, and more preferably 2 in terms of causing moderate crosslinking of the polymer (A) and availability. Particularly preferred.

Examples of the monovalent organic group having 1 to 30 carbon atoms in X ² include a hydrocarbon group such as a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and a carbon-carbon in the hydrocarbon group. Functional groups such as —O—, —COO—, —CO—, —NHCO—, —S—, and —NH— are introduced between the bonds or at a position adjacent to the carbonyl group in formula (b-1). And the like. In addition, each of these groups may have a substituent such as a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkoxy group. Specific examples of the monovalent hydrocarbon group for X ² include groups exemplified in the description of R ¹ above.
X ² preferably has 1 to 6 carbon atoms in terms of reducing the amount of “H—X ² ” produced by regeneration of the isocyanate group by heating remaining in the reaction system. 4 is more preferable.

（式（ｘ２−１）〜（ｘ２−７）中、Ｒ^２、Ｒ^５、Ｒ^６、Ｒ^７及びＲ^９は、それぞれ独立に１価の炭化水素基である。Ｒ^３及びＲ^４は、それぞれ独立に、１価の炭化水素基又は基「−Ｏ−Ｒ^１０」（但し、Ｒ^１０は１価の炭化水素基を示す。）である。Ｒ^８は、１価の芳香族炭化水素基である。ｍは２〜１１の整数である。「＊」は、カルボニル基との結合手を示す。） Examples of X ² include groups represented by the following formulas (x2-1) to (x2-7).

(In the formulas (x2-1) to (x2-7), R ² , R ⁵ , R ⁶ , R ⁷ and R ⁹ are each independently a monovalent hydrocarbon group. R ³ and R ⁴ are Each independently represents a monovalent hydrocarbon group or a group “—O—R ¹⁰ ” (where R ¹⁰ represents a monovalent hydrocarbon group), and R ⁸ represents a monovalent aromatic hydrocarbon group. M is an integer of 2 to 11. “*” represents a bond with a carbonyl group.)

Specific examples of the monovalent hydrocarbon group for R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ include the groups exemplified as the monovalent hydrocarbon group for R ^1. Is mentioned. R ^{2 to} R ¹⁰ each preferably have 1 to 30 carbon atoms.
m is preferably an integer of 3 to 8, and more preferably an integer of 4 to 6.
X ² is preferably a group represented by the above formula (x2-1) among the above from the viewpoint that the effect of the detached X ² on the film properties is small. R ^{2 in} X ² is preferably a monovalent hydrocarbon group having 1 to 30 carbon atoms, and more preferably a monovalent chain hydrocarbon group having 1 to 30 carbon atoms. The monovalent chain hydrocarbon group of R ² preferably has 1 to 10 carbon atoms from the viewpoint of reducing the residual amount in the reaction system of “H—X ² ” generated by regeneration of the isocyanate group. 1 to 6 is more preferable, 1 to 4 is more preferable, and an alkyl group having 1 to 4 carbon atoms is particularly preferable.

（式中、「＊」は、カルボニル基との結合手を示す。） Preferable specific examples of X ² include groups represented by the following formulas (x2-1-1) to (x2-7-1), for example.

(In the formula, “*” represents a bond with a carbonyl group.)

Specific examples of the compound (B) include compounds represented by the following formulas (b-1-1) to (b-1-11), for example. In addition, as a compound (B), 1 type can be used individually or in combination of 2 or more types.

The blending ratio of the compound (B) is preferably 0.1 to 50 parts by weight, and 0.5 to 30 parts by weight with respect to 100 parts by weight of the total amount of the polymer components contained in the liquid crystal aligning agent. More preferably, it is more preferably 1 to 20 parts by weight.
When a film is formed using the liquid crystal aligning agent of the present invention, X ² is dissociated from the above compound (B) by heating (post-baking) during film formation to regenerate the isocyanate group, and the regenerated isocyanate It is considered that the group and the carboxyl group of the polymer (A) react to form a crosslinked structure.
The content ratio of the blocked isocyanate group (—NR ¹ —CO—X ² ) in the liquid crystal aligning agent is 0.01 to 1.0 with respect to 1 equivalent of the carboxyl group of the polymer (A) in the liquid crystal aligning agent. The ratio which becomes an equivalent is preferable, and the ratio which becomes 0.1-1.0 equivalent is more preferable.

  The compounding ratio of the compound (B-1) is preferably 0.1 to 50 parts by weight, and 0.5 to 30 parts by weight with respect to 100 parts by weight of the total amount of the polymer components contained in the liquid crystal aligning agent. More preferably, it is 1 to 20 parts by weight.

<Other ingredients>
The liquid crystal aligning agent of this invention may contain other components other than the said polymer (A) and the said compound (B) as needed. Examples of such other components include other polymers other than the polymer (A), compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy group-containing compound”), functional silane compounds, and the like. Can be mentioned.

[Other polymers]
The above other polymers can be used for improving solution properties and electrical properties. Examples of such other polymers include polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate.
When other polymers are added to the liquid crystal aligning agent, the blending ratio is preferably 50% by weight or less, more preferably 0.1 to 40% by weight, more preferably 0.1% by weight to the total amount of the polymer in the composition. 1 to 30% by weight is more preferable.

[Epoxy group-containing compound]
The epoxy group-containing compound can be used to improve the adhesion and electrical properties with the substrate surface in the liquid crystal alignment film. 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 Enirumetan, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, N, N-diglycidyl - may be mentioned as being preferred and cyclohexylamine. In addition, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can also be used.
When these epoxy compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the total of the polymers contained in the liquid crystal aligning agent. preferable.

[Functional silane compounds]
The functional silane compound can be used for the purpose of improving the printability of the liquid crystal aligning agent. Examples of such functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl). ) -3-Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3- Aminopropyltrimethoxysilane, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-trimethoxysilyl -3,6- Methyl azananoate, N-benzyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycid And xylpropyltrimethoxysilane.
When these functional silane compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight, based on 100 parts by weight of the total polymer.

  As other components, in addition to the above, a compound having at least one oxetanyl group in the molecule, an antioxidant, or the like can be used.

[solvent]
In the liquid crystal aligning agent of the present invention, the polymer (A), the blocked isocyanate compound (B) as an additive component, and other components used as necessary are preferably dispersed or dissolved in an appropriate organic solvent. It is prepared as a liquid composition.

  Examples of the organic 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 Recall 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. be able to. These can be used alone or in admixture of two or more.

  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 content concentration varies depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the 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 in the range of 1.5 to 4.5% by weight. It is particularly preferred. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and thereby the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, and thereby the solution viscosity is in the range of 3 to 15 mPa · s. The temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 10-50 degreeC, More preferably, it is 20-30 degreeC.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film of the present invention is formed by the liquid crystal aligning agent prepared as described above. Moreover, the liquid crystal display element of this invention comprises the liquid crystal aligning film formed using the said liquid crystal aligning agent. The driving mode of the liquid crystal display element is not particularly limited, and can be applied to various driving modes such as a TN type, STN type, IPS type, FFS type, VA type, MVA type, and PSA type.

  The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (3). In step (1), the substrate to be used varies depending on the desired drive mode. Step (2) and step (3) are common to each drive mode.

[Step (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.
(1-1) When manufacturing a TN type, STN type, VA type, MVA type or PSA type liquid crystal display element, a pair of substrates each provided with a patterned transparent conductive film is used as a pair. The liquid crystal aligning agent of the present invention is preferably applied onto the surface on which the transparent conductive film is formed, preferably by an offset printing method, a spin coating method, a roll coater method or an ink jet printing method. Here, as the substrate, for example, glass such as float glass or soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, poly (cycloaliphatic olefin) can be used. As a transparent conductive film provided on one surface of the substrate, an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), etc. Can be used. In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photo-etching after forming a transparent conductive film without a pattern, a method of using a mask having a desired pattern when forming a transparent conductive film, etc. be able to. In 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 the application of the liquid crystal aligning agent, preheating (pre-baking) is preferably performed for the purpose of preventing dripping of the applied 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, more preferably 0.5 to 5 minutes. Thereafter, a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, for thermal imidization of the amic acid structure present in the polymer. 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.

  (1-2) 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, and 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 (1-1). As the metal film, for example, a film made of a metal such as chromium can be used.

  In both cases (1-1) and (1-2), after applying a liquid crystal aligning agent on the substrate, a coating film to be an alignment film is formed by removing the organic solvent. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid, a polyamic acid ester, or an imidized polymer having an imide ring structure and an amic acid structure, It is good also as a more imidized coating film by advancing the dehydration ring-closing reaction by further heating after the coating film formation.

[Step (2): rubbing treatment]
When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal display element, the coating film formed in the above step (1) is fixed by a roll wound with a cloth made of fibers such as nylon, rayon, and cotton. A rubbing process that rubs in the direction is performed. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film. On the other hand, when manufacturing a VA type liquid crystal display element, the coating film formed in the step (1) can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to a rubbing treatment. In addition, 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 rays, After forming a resist film in part and performing a rubbing process in a direction different from the previous rubbing process, a process for removing the resist film is performed so that the liquid crystal alignment film has different liquid crystal alignment capabilities for each region. Good. In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element.
When manufacturing a PSA type liquid crystal display element, the following step (3) may be carried out using the coating film formed in the above step (1) as it is, but the fall of the liquid crystal molecules is controlled and the alignment is divided. A weak rubbing treatment may be performed for the purpose of performing the above in a simple manner.

[Step (3): Construction of liquid crystal cell]
(3-1) A liquid crystal cell is manufactured by preparing two substrates on which a liquid crystal alignment film is formed as described above and disposing a liquid crystal between the two substrates facing each other. In order to manufacture a liquid crystal cell, the following two methods are mentioned, for example. First, the first method is a conventionally known method. In this method, first, two substrates are arranged to face each other through a gap (cell gap) so that the respective liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealant, and the substrate surface And after injecting and filling a liquid crystal in the cell gap divided by the sealing agent, a liquid crystal cell is manufactured by sealing the injection hole. The second method is a method called an ODF (One Drop Fill) method. In this 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 further, a predetermined number of locations on the liquid crystal alignment film surface are applied. After the liquid crystal is dropped on the other substrate, the other substrate is bonded so that the liquid crystal alignment film faces. A liquid crystal cell is manufactured by spreading the liquid crystal over the entire surface of the substrate and then irradiating the entire surface of the substrate with ultraviolet light to cure the sealant. Regardless of which method is used, the liquid crystal cell manufactured as described above is further heated to a temperature at which the liquid crystal used takes an isotropic phase, and then slowly cooled to room temperature, thereby removing the flow alignment at the time of filling the liquid crystal. It is desirable to do.

  As the sealing agent, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as a spacer can be used. Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenyl cyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals. Biphenylcyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal, bicyclooctane liquid crystal, cubane liquid crystal, 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.

(3-2) When manufacturing a PSA type liquid crystal display element, a liquid crystal cell is constructed in the same manner as in the above (3-1) except that a photopolymerizable compound is injected or dropped together with a liquid crystal. Thereafter, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. The voltage applied here can be, for example, 5 to 50 V direct current or alternating current. Moreover, as light to irradiate, the ultraviolet-ray and visible light which contain light with a wavelength of 150-800 nm can be used, for example, However, The ultraviolet-ray containing light with a wavelength of 300-400 nm is preferable. As a light source of irradiation light, for example, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. In addition, the ultraviolet rays in the above preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter diffraction grating. The irradiation dose of light, preferably less than 1,000 J / ^{m 2} or more 200,000 J / ^{m 2,} more preferably from 1,000~100,000J / ^{m 2.}

  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. When the rubbing treatment is performed on the coating film, the two substrates are arranged to face each other so that the rubbing directions in each coating film are at a predetermined angle, for example, orthogonal or antiparallel.

  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, It can be used for display devices such as various monitors and liquid crystal televisions.

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

In the following Examples and Comparative Examples, the imidization ratio of polyimide in the polymer solution, the solution viscosity of the polymer solution, the weight average molecular weight of the polymer, and the epoxy equivalent were measured by the following methods.
[Imidation rate of polyimide]
The polyimide solution was poured into pure water, and the resulting precipitate was sufficiently dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidation ratio [%] was determined by the following mathematical formula (1).
Imidation ratio [%] = (1-A ¹ / A ² × α) × 100 (1)
(In Formula (1), A ¹ is a peak area derived from protons of NH groups appearing near a chemical shift of 10 ppm, A ² is a peak area derived from other protons, and α is a precursor of a polymer (polyamic acid). The number ratio of other protons to one proton of NH group in)
[Solution viscosity of polymer solution]
The solution viscosity [mPa · s] of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer for a solution prepared to a polymer concentration of 10% by weight using a predetermined solvent.
[Weight average molecular weight of polymer]
The weight average molecular weight is a polystyrene equivalent value measured by gel permeation chromatography under the following conditions.
Column: Tosoh Co., Ltd., TSKgelGRCXLII
Solvent: Tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent was measured by the hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.

<Synthesis of polymer (A)>
[Synthesis Example 1: Synthesis of polyimide (PI-1)]
2,2.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of p-phenylenediamine as diamine, and 3,5- 10.5 g (0.02 mol) of cholestanyl diaminobenzoate is dissolved in 166 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. It was. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 90 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration cyclization reaction, the solvent in the system was replaced with new NMP (by this operation, pyridine and acetic anhydride used in the dehydration cyclization reaction were removed from the system. The same applies hereinafter), whereby the imidation rate was about 68. A solution containing 26% by weight of polyimide (PI-1) was obtained. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s.

[Synthesis Example 2: Synthesis of polyimide (PI-2)]
2,3,5-tricarboxycyclopentylacetic acid dianhydride 22.5 g (0.1 mol) as tetracarboxylic dianhydride, 10.7 g (0.07 mol) 3,5-diaminobenzoic acid as diamine, Tanyloxy-2,4-diaminobenzene 7.35 g (0.015 mol) and 6.94 g (0.015 mol) of the compound represented by the above formula (D-1-5) were dissolved in 190 g of NMP. The reaction was carried out at 0 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 80 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 15.7 g of pyridine and 20.3 g of acetic anhydride were added, and a dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-2) having an imidation ratio of about 80%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s.

[Synthesis Example 3: Synthesis of polyimide (PI-3)]
2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8-dianhydride 18.7 g (0.075 mol) and 1,4,6 as tetracarboxylic dianhydride 2.3,4 g (0.025 mol) of 2,3,4-cyclobutanetetracarboxylic dianhydride, 10.7 g (0.07 mol) of 3,5-diaminobenzoic acid as diamine and 1,3-diamino-4- {4- [trans-4- (trans-4-n-pentylcyclohexyl) cyclohexyl] phenoxy} benzene (compound represented by the above formula (D-1-2)) (13.1 g, 0.03 mol) It melt | dissolved in 190 g of NMP, reaction was performed at 60 degreeC for 6 hours, and the solution containing 20 weight% of polyamic acids was obtained. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 85 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 9.5 g of pyridine and 12.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration and cyclization reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-3) having an imidation ratio of about 65%. A small amount of the obtained polyimide solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 45 mPa · s.

[Synthesis Example 4: Synthesis of polyimide (PI-4)]
As tetracarboxylic dianhydride, 110 g (0.50 mol) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- ( Tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione 160 g (0.50 mol), as diamine, 91 g (0.85 mol) of p-phenylenediamine, 25 g (0.10 mol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane and 25 g (0.040 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, and aniline as monoamine 4 g (0.015 mol) was dissolved in 960 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 60 mPa · s.
Next, 2,700 g of NMP was added to the obtained polyamic acid solution, 390 g of pyridine and 410 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with new γ-butyrolactone to obtain about 2,500 g of a solution containing 15% by weight of polyimide (PI-4) having an imidation ratio of about 95%. A small amount of this solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 70 mPa · s.

[Synthesis Example 5: Synthesis of polyimide (PI-5)]
2,2.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 8.6 g (0.08 mol) of p-phenylenediamine as diamine, 4,4 ′ -Dissolve 2.0 g (0.01 mol) of diaminodiphenylmethane and 3.2 g (0.01 mol) of 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl in 324 g of NMP, The reaction was carried out for 4 hours to obtain a solution containing 10% by weight of polyamic acid.
Next, 360 g of NMP was added to the obtained polyamic acid solution, 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 10% by weight of polyimide (PI-5) having an imidization ratio of about 93%. A small amount of the obtained polyimide solution was taken and measured, and the solution viscosity was 30 mPa · s.

[Synthesis Example 6: Synthesis of polyimide (PI-6)]
2,3,5-tricarboxycyclopentylacetic acid dianhydride 22.4 g (0.1 mol) as tetracarboxylic dianhydride, 12.2 g (0.08 mol) 3,5-diaminobenzoic acid as diamine and choles Tanyloxy-2,4-diaminobenzene 9.80 g (0.02 mol) was dissolved in 178 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing 20% by weight of polyamic acid. A small amount of the obtained polyamic acid solution was collected, NMP was added, and the solution viscosity measured as a solution having a polyamic acid concentration of 10% by weight was 80 mPa · s.
Next, NMP was added to the obtained polyamic acid solution to obtain a polyamic acid concentration of 7% by weight, 11.9 g of pyridine and 15.3 g of acetic anhydride were added, and dehydration ring closure reaction was performed at 110 ° C. for 4 hours. . After the dehydration ring closure reaction, the solvent in the system was replaced with new NMP to obtain a solution containing 26% by weight of polyimide (PI-6) having an imidation ratio of about 65%. A small amount of the obtained polyimide solution was taken, NMP was added, and the solution viscosity measured as a solution having a polyimide concentration of 10% by weight was 40 mPa · s.

[Synthesis Example 7: Synthesis of polyorganosiloxane (APS-1)]
A reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux condenser was charged with 100.0 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 500 g of methyl isobutyl ketone and 10.0 g of triethylamine, and room temperature. Mixed with. Next, 100 g of deionized water was dropped from the dropping funnel over 30 minutes, and the reaction was performed at 80 ° C. for 6 hours while stirring under reflux. After completion of the reaction, the organic layer was taken out and washed with a 0.2 wt% ammonium nitrate aqueous solution until the water after washing became neutral, and then the solvent and water were distilled off under reduced pressure, whereby an epoxy group-containing polyorgano Siloxane (EPS-1) was obtained as a viscous transparent liquid. When this epoxy group-containing polyorganosiloxane (EPS-1) was analyzed by ¹ H-NMR, a peak based on the epoxy group was obtained in the vicinity of the chemical shift (δ) = 3.2 ppm according to the theoretical intensity. It was confirmed that no side reaction of the epoxy group occurred. The resulting epoxy group-containing polyorganosiloxane had a weight average molecular weight Mw of 3,500 and an epoxy equivalent of 180 g / mol.
Next, in a 200 mL three-necked flask, 10.0 g of epoxy group-containing polyorganosiloxane (EPS-1), 30.28 g of methyl isobutyl ketone as a solvent, 3.98 g of 4-dodecyloxybenzoic acid, and UCAT 18X (product) Name, manufactured by San Apro Co., Ltd.) 0.10 g, and reacted at 100 ° C. with stirring for 48 hours. After completion of the reaction, a solution obtained by adding ethyl acetate to the reaction mixture was washed with water three times, the organic layer was dried using magnesium sulfate, and then the solvent was distilled off to obtain a liquid crystal alignment polyorganosiloxane (APS-). 9.0 g of 1) was obtained. The weight average molecular weight Mw of the obtained polymer was 9,900.

<Example 1>
[Preparation of liquid crystal aligning agent]
In a solution containing polyimide (PI-1) as the polymer (A), an NMP solution of the compound represented by the above formula (b-1-1) as the blocked isocyanate compound (B) is added by 100 parts by weight of the polymer. 5 parts by weight was added to the solution, and the solution composition was NMP: BC = 50: 50 (weight ratio) and the solid content concentration was 6.0% by weight. A liquid crystal aligning agent (S1) was prepared by filtering this solution using a filter having a pore diameter of 1 μm.

[Manufacture of liquid crystal cells]
The liquid crystal aligning agent (S1) prepared above was applied to a transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a liquid crystal aligning film printer (Nissha Printing Co., Ltd.), and hot at 80 ° C. After removing the solvent by heating (pre-baking) for 1 minute on the plate, heating (post-baking) for 30 minutes on a 210 ° C. hot plate was performed to form a coating film having an average film thickness of 80 nm.
The coating film is 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. did. 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. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film.
Next, on each 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 liquid crystal alignment film surfaces are overlapped. And then the adhesive was cured. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck & Co., Inc.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photo-curing adhesive to produce a liquid crystal cell.

[Evaluation of reliability of liquid crystal alignment film]
A voltage of 5 V was applied to the liquid crystal cell obtained above with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR1) 167 milliseconds after release of application was measured. Next, the liquid crystal cell was allowed to stand in an 80 ° C. oven under LED lamp irradiation for 200 hours, and then allowed to stand at room temperature and naturally cooled to room temperature. After cooling, a voltage of 5 V was applied to the liquid crystal cell with an application time of 60 microseconds and a span of 167 milliseconds, and then the voltage holding ratio (VHR2) 167 milliseconds after the application release was measured. The measuring device used was “VHR-1” manufactured by Toyo Corporation. The change rate (ΔVHR) of VHR at this time was calculated by the following mathematical formula (2), and the reliability of the liquid crystal alignment film was evaluated by ΔVHR.
ΔVHR [%] = (VHR1−VHR2) / (VHR1) × 100 (2)
In the evaluation, when ΔVHR is 0% or more and less than 0.4%, the reliability is “particularly good (」) ”, and when ΔVHR is 0.4% or more and less than 1.5%, the reliability is“ good (◯) ”. The reliability was “good (Δ)” when 1.5% or more and 2.0% or less, and the reliability was “bad (×)” when greater than 2.0%. As a result, in the liquid crystal cell, ΔVHR = 0.5 [%], and the reliability was good.

<Examples 2 to 9 and Comparative Example 1>
Liquid crystal aligning agents (S2) to (S9) and (R1) were prepared in the same manner as in Example 1 except that the types and amounts of the polymer component and additive component used were changed as shown in Table 1 below. For each of the prepared liquid crystal aligning agents, the reliability of the liquid crystal cell was evaluated in the same manner as in Example 1 above. The results are shown in Table 1 below.

In Table 1, “Amount” in the polymer component column indicates each orientation ratio (parts by weight) relative to 100 parts by weight of the total amount of polymer components contained in the liquid crystal aligning agent. In addition, “addition amount” in the additive column indicates an alignment ratio (parts by weight) with respect to 100 parts by weight of the total amount of the polymer components in the liquid crystal alignment agent. Abbreviations of additives in Table 1 have the following meanings.
Add-1: Compound represented by the above formula (b-1-1) Add-2: Compound represented by the above formula (b-1-2) Add-3: Represented by the following formula (m-1) Compound

  As shown in Table 1, in Examples 1 to 9, ΔVHR was as small as less than 1.0, and the reliability of the liquid crystal display element was “good”. On the other hand, in Comparative Example 1, ΔVHR was as large as 2.9 and the reliability was “bad”.

<Examples 10 to 13 and Comparative Example 2>
Liquid crystal aligning agents (S10) to (S13) and (R2) were prepared in the same manner as in Example 1 except that the types and amounts of the polymer component and additive component used were changed as shown in Table 2 below. For each of the prepared liquid crystal aligning agents, the reliability of the liquid crystal cell was evaluated in the same manner as in Example 1 above. The results are shown in Table 2 below.

In Table 2, the numerical values indicated by the “amount” in the polymer component column and the “addition amount” in the additive column are the same as in Table 1 above. Abbreviations of additives in Table 2 have the following meanings.
Add-4: Compound represented by the above formula (b-1-9) Add-5: Compound represented by the above formula (b-1-10) Add-6: Represented by the following formula (m-2) Compound Add-7: Compound represented by the above formula (b-1-11)

  As shown in Table 2, in Examples 10 to 12, ΔVHR was as small as 0.2% or less, and the reliability of the liquid crystal display element was evaluated as “particularly good”. In Example 13, ΔVHR was 1.8%, and the reliability was evaluated as “good”. On the other hand, in Comparative Example 2, ΔVHR was as large as 2.5%, and the reliability was “bad”.

Claims (13)

  A liquid crystal aligning agent containing at least one polymer (A) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and a polyfunctional block isocyanate compound (B-1) having an aromatic ring. The liquid crystal aligning agent of Claim 1 whose said block isocyanate compound (B-1) is a compound represented by a following formula (b1-1).

(In Formula (b1-1), R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, X ¹¹ is an n-valent organic group having an aromatic ring, and X ² is , A monovalent organic group having 1 to 30 carbon atoms, n is an integer of 2 to 6. However, a plurality of R ¹ in the formula may be the same or different, and a plurality of X ² may be the same. May be different.) The liquid crystal aligning agent according to claim 2, wherein X ¹¹ is an n-valent aromatic hydrocarbon group having 5 to 30 carbon atoms or an n-valent group having an aromatic heterocyclic ring. 4. The liquid crystal aligning agent according to claim 2, wherein X ¹¹ is an n-valent group obtained by removing n hydrogen atoms from a ring portion of an aromatic hydrocarbon having 5 to 30 carbon atoms. 4. The liquid crystal aligning agent according to claim 2, wherein X ¹¹ is an n-valent organic group having an aromatic heterocyclic ring. The liquid crystal aligning agent according to claim 5, wherein X ¹¹ is an n-valent group obtained by removing n hydrogen atoms from a ring portion of an aromatic heterocyclic ring. X ² is a group “* —O—R ² ” (where R ² is a monovalent hydrocarbon group having 1 to 30 carbon atoms, and “*” represents a bond with a carbonyl group). The liquid crystal aligning agent as described in any one of Claims 2-6 which exists. The liquid crystal aligning agent according to claim 7, wherein R ² is a monovalent chain hydrocarbon group having 1 to 30 carbon atoms. Wherein X ¹¹ is an n-valent organic group having 3 to 15 carbon atoms having an aromatic ring, the liquid crystal alignment agent according to any one of claims 2-8.   Content of the said block isocyanate compound (B-1) is 0.1-50 weight part with respect to 100 weight part of whole quantity of the polymer component contained in the said liquid crystal aligning agent. The liquid crystal aligning agent as described in any one.   As the polymer (A), 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4,6: 8- Dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride The tetracarboxylic dianhydride containing at least one selected from the group consisting of anhydrides and at least one of polyamic acid and polyimide obtained by reacting diamine, according to any one of claims 1 to 10. The liquid crystal aligning agent of description.   The liquid crystal aligning film formed using the liquid crystal aligning agent as described in any one of Claims 1-11.   A liquid crystal display device comprising the liquid crystal alignment film according to claim 12.