JP6596931B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

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

  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, a TN (Twisted Nematic) type or STN (Super Twisted Nematic) type has been developed. Various liquid crystal display elements such as a type, a VA (Vertical Alignment) type, an IPS (In-Plane Switching) type, and an FFS (fringe field switching) 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, mobile terminals such as smartphones and PDAs (Personal Digital Assistance), and small display terminals such as tablet PCs have become widespread, and the demand for higher definition for liquid crystal panels is increasing. Based on this background, various liquid crystal aligning agents have been proposed in order to improve the display quality and reliability of the liquid crystal panel (see, for example, Patent Document 1). In Patent Document 1, an epoxy compound having a specific structure is contained in a liquid crystal alignment agent together with a polymer component of polyamic acid or polyimide, and a liquid crystal alignment film is formed using the liquid crystal alignment agent. It is disclosed that liquid crystal alignment and reliability are improved. In recent years, with an increase in demand for tablet terminals and mobile terminals, touch panel type liquid crystal displays are increasing.

JP 2008-299318 A

  Touch-panel type liquid crystal displays are highly resistant to external pressure such as pressing with a finger or a pointing device such as a pen.In other words, even when external pressure is applied, alignment defects and bright spot defects are less likely to occur. Desired. In recent years, tablet terminals and mobile terminals have become lighter and thinner, and in the panel assembly process at the time of manufacturing a liquid crystal display, the panel is easily distorted or stress is easily applied to the inside of the panel. Such distortion and stress of the panel cause peeling of the alignment film from the substrate, and also cause a bright spot defect and an alignment defect. Therefore, the liquid crystal alignment film is required to be less likely to peel off the substrate.

  Particularly in recent years, the size of one pixel has become smaller than before due to the higher definition of liquid crystal display elements, and the number of steps due to electronic components mounted on the substrate is formed on the substrate on which the liquid crystal alignment film is formed. Has increased. Therefore, it can be said that the liquid crystal alignment film in recent years is easily subjected to higher stress than before due to the rubbing treatment, and the scratches and film peeling are likely to occur. On the other hand, since scratches or peeling off in the liquid crystal alignment film cause display defects, the liquid crystal alignment film is required to have high rubbing resistance.

  The present invention has been made in view of the above problems, and provides a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having good rubbing resistance and a liquid crystal display element having high resistance to external pressure. One purpose.

  The present inventors diligently studied to solve the above-described problems of the prior art, and when a silicon compound having a specific structure was included in the liquid crystal aligning agent, the rubbing resistance of the liquid crystal alignment film and the exterior of the liquid crystal display element The inventors have found that an effect of improving resistance to pressure can be obtained, and have completed the present invention. 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 (P) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and an organosilicon compound having a nitrogen-containing structure represented by the following formula (1a) ( However, “* 1” in the following formula (1a) is bonded to a hydrogen atom, a methylene group, or a monovalent hydrocarbon group).

（式（１ａ）中、Ｒ^ａ及びＲ^ｂはそれぞれ独立に２価の有機基である。「＊１」及び「＊２」は結合手を示す。）

(In Formula (1a), R ^a and R ^b are each independently a divalent organic group. “* 1” and “* 2” represent a bond.)

In one aspect, the present invention has at least one polymer (P) selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, a nitrogen-containing structure represented by the above formula (1a), and a molecule. There is provided a liquid crystal aligning agent comprising an organosilicon compound satisfying at least one of having a hydroxy group therein and R ^a in the formula (1a) being ^a carbonyl group.

  In another aspect, a liquid crystal alignment film formed using the liquid crystal alignment agent and a liquid crystal display element including the liquid crystal alignment film are provided.

  According to the liquid crystal aligning agent containing the specific organosilicon compound described above, a liquid crystal aligning film having good rubbing resistance can be obtained. In addition, a liquid crystal display element having high resistance to external pressure can be obtained.

  The liquid crystal aligning agent of the present disclosure is a liquid polymer composition in which a polymer component is preferably dissolved or dispersed in an organic solvent. Below, each component contained in the liquid crystal aligning agent of this indication and the other component arbitrarily mix | blended as needed are demonstrated.

<Polymer (P)>
The liquid crystal aligning agent of this indication contains at least 1 type of polymer (P) chosen from the group which consists of a polyamic acid, a polyimide, and a polyamic acid ester as a polymer component.

[Polyamic acid]
The polyamic acid contained in the liquid crystal aligning agent of this indication can be obtained by making tetracarboxylic dianhydride and diamine react, for example.
(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) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl) -8 -Methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro -3 ′-(tetrahydrofuran-2 ′, 5′-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3 , 5,6-To Carboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 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, ethylenediaminetetraacetic acid dianhydride, cyclopentanetetracarboxylic dianhydride and the like;

  Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, ethylene glycol bis (anhydrotrimellitate), 1,3-propylene glycol bis (anhydrotrimellitate); In addition, the tetracarboxylic dianhydride 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.

  As tetracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid 2: 3,5 is preferable in that the liquid crystal orientation and the solubility in a solvent can be improved. : 6-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-dioxotetrahydrofuran-3- Yl) -3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxotetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-dianhydride, cyclohexanetetra Carboxylic acid dianhydride preferably comprises 1,3-propylene glycol bis (anhydrotrimellitate) and at least one compound selected from the group consisting of pyromellitic dianhydride. The amount of these preferred compounds used (the total amount when two or more are used) is preferably 5 mol% or more based on the total amount of tetracarboxylic dianhydride used for the synthesis of polyamic acid. It is more preferable to set it as 10 mol% or more, and it is more preferable to set it as 20 mol% or more.

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

（式（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は炭素数１〜３のアルカンジイル基であり、Ｒ^ＩＩは単結合又は炭素数１〜３のアルカンジイル基であり、ａは０又は１であり、ｂは０〜２の整数であり、ｃは１〜２０の整数であり、ｄは０又は１である。但し、ａ及びｂが同時に０になることはない。）
で表される化合物、光配向性構造を有するジアミンなどの配向性基含有ジアミン： Examples of aromatic diamines include dodecanoxydiaminobenzene, tetradecanoxydiaminobenzene, pentadecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, and cholesteryloxydiaminobenzene. Cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostannyl diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 1,1-bis (4 -((Aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((amino Phenoxy Methyl) phenyl) -4-heptylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4- (4-heptylcyclohexyl) cyclohexane, N- (2,4-diaminophenyl) -4 -(4-Heptylcyclohexyl) benzamide, the following formula (D-1)

(In Formula (D-1), X ^I and X ^II are each independently a single bond, —O—, —COO— or —OCO—, and R ^I is an alkanediyl group having 1 to 3 carbon atoms. R ^II is a single bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, 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 are not 0 at the same time.)
An orientation group-containing diamine such as a diamine having a photo-orientation structure represented by:

p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylamine, 4,4′-diaminodiphenyl sulfide, 4-aminophenyl-4′-aminobenzoate, 4,4′-diaminoazobenzene, 1 , 5-bis (4-aminophenoxy) pentane, 1,7-bis (4-aminophenoxy) heptane, bis [2- (4-aminophenyl) ethyl] hexanedioic acid, N, N-bis (4-amino) Phenyl) methylamine, 1,5-diaminonaphthalene, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl, 4,4 '-Diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophen Fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '-(p-phenylenediisopropyl Riden) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diamino Acridine, 3,6-diaminocarbazole, N-methyl-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, 4,4 ′-[4,4 ′ Propane-1,3-diyl bis (piperidine-1,4-diyl)] dianiline, 4,4' other diamines, such as diaminodiphenyl triphenylamine, and the like;
Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; and the diamines described in JP-A 2010-97188 can be used.

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

なお、ポリアミック酸の合成に使用するジアミンとしては、これらの化合物の１種を単独で又は２種以上を適宜選択して使用することができる。 Specific examples of the compound represented by the formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-4).

In addition, as diamine used for the synthesis | combination of a polyamic acid, 1 type of these compounds can be used individually or in combination of 2 or more types as appropriate.

  When applied to a liquid crystal aligning agent for TN type, STN type or vertical alignment type liquid crystal display elements, a group (orientation group) capable of imparting liquid crystal alignment ability to the coating film is introduced into the side chain of the polyamic acid. May be. Examples of such an orientation group include a group having a straight chain structure, a group having a mesogen skeleton, and a group having a bulky structure. Specifically, for example, an alkyl group having 4 to 20 carbon atoms, a carbon number of 4 -20-fluoroalkyl group, C4-C20 alkoxy group, group having a steroid skeleton having 17-51 carbon atoms, or a group in which a plurality of rings are bonded directly or via a linking group. The polyamic acid having an orientation group can be obtained, for example, by polymerization containing an orientation group-containing diamine in the monomer composition. In the case of using an orientation group-containing diamine, the blending ratio is preferably 3 mol% or more with respect to the total diamine used in the synthesis, from the viewpoint of improving liquid crystal orientation, and is preferably 5 to 70 mol%. More preferably.

(Synthesis of polyamic acid)
The polyamic acid can be obtained by reacting the above tetracarboxylic dianhydride and diamine together with a molecular weight adjusting agent as necessary. The ratio of the tetracarboxylic dianhydride and the diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the tetracarboxylic dianhydride acid anhydride group to 1 equivalent of the amino group of the diamine. The ratio which becomes an equivalent is preferable, and the ratio which becomes 0.3-1.2 equivalent is more preferable.
Examples of the molecular weight regulator include acid monoanhydrides such as maleic anhydride, phthalic anhydride and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, n-butylamine and stearylamine; monoisocyanates such as phenyl isocyanate and naphthyl isocyanate A compound etc. can be mentioned. The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used.

  The polyamic acid synthesis reaction is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20 ° C to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably from 0.1 to 24 hours, more preferably from 0.5 to 12 hours.

  Examples of the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like. Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and a phenolic solvent (first group organic solvent), or one or more selected from the first group of organic solvents And a mixture of at least one selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (second-group organic solvent). In the latter case, the proportion of the second group organic solvent used is preferably 50% by weight or less, more preferably 40% by weight, based on the total amount of the first group organic solvent and the second group organic solvent. Or less, more preferably 30% by weight or less.

  Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. And at least one selected from the group consisting of halogenated phenols is used as a solvent, or a mixture of one or more of these and another organic solvent is preferably used in the above range. 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. Prefer

  As described above, a reaction solution obtained by dissolving polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal aligning agent, may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution, or the isolated polyamic acid was purified. You may use for preparation of a liquid crystal aligning agent. When polyamic acid is dehydrated and cyclized into a polyimide, the above reaction solution may be directly subjected to dehydration and cyclization reaction, or may be subjected to dehydration and cyclization reaction after isolating the polyamic acid contained in the reaction solution. Alternatively, the isolated polyamic acid may be purified and then subjected to a dehydration ring closure reaction. Isolation and purification of the polyamic acid can be performed according to known methods.

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

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

  The tetracarboxylic acid diester used in the method [II] can be obtained, for example, by ring-opening the tetracarboxylic dianhydride exemplified in the synthesis of the polyamic acid with the above alcohols. In the method [II], the tetracarboxylic acid derivative used may be only a tetracarboxylic acid diester, or a tetracarboxylic dianhydride may be used in combination. Examples of the diamine used in Method [II] include the diamines exemplified in the synthesis of polyamic acid. The reaction of Method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. As an organic solvent, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. Examples of the dehydration catalyst include 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium halide, carbonylimidazole, a phosphorus condensing agent, and the like.

The tetracarboxylic acid diester dihalide used in the method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with an appropriate chlorinating agent such as thionyl chloride. In Method [III], the tetracarboxylic acid derivative used may be only a tetracarboxylic acid diester dihalide, or a tetracarboxylic dianhydride may be used in combination. Examples of the diamine used in Method [III] include the diamines exemplified in the synthesis of polyamic acid. The reaction of Method [III] is preferably carried out in an organic solvent in the presence of a suitable base. As an organic solvent, the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid can be mentioned. As the base, for example, tertiary amines such as pyridine and triethylamine can be preferably used.
In addition, the polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist.

  The reaction solution obtained by dissolving the polyamic acid ester may be used for the preparation of the liquid crystal aligning agent as it is, or may be used for the preparation of the liquid crystal aligning agent after isolating the polyamic acid ester contained in the reaction solution, Or after purifying the isolated polyamic acid ester, you may use for preparation of a liquid crystal aligning agent. Isolation and purification of the polyamic acid ester can be performed according to a known method.

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

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

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

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

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

The polymer (P) obtained as described above preferably has a solution viscosity of 20 to 1,800 mPa · s when it is made into a solution having a concentration of 15% by weight. More preferably, it has a solution viscosity of 500 mPa · s. The solution viscosity (mPa · s) of the polymer (P) is 15% by weight with a concentration of 15% by weight prepared using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) of the polymer (P). It is a value measured at 25 ° C. using an E-type viscometer for the polymer solution.
The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the polymer (P) 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 between Mw and the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. By being in such a molecular weight range, it is possible to ensure good orientation and stability of the liquid crystal display element.

（式（１ａ）中、Ｒ^ａ及びＲ^ｂはそれぞれ独立に２価の有機基である。「＊１」及び「＊２」は結合手を示す。） <Organic silicon compound>
The liquid crystal aligning agent of this indication contains the organosilicon compound (henceforth a "specific silicon compound") which has a nitrogen-containing structure represented by following formula (1a) as an additive with the said polymer (P). To do.

(In Formula (1a), R ^a and R ^b are each independently a divalent organic group. “* 1” and “* 2” represent a bond.)

In the above formula (1a), examples of the divalent organic group represented by R ^a and R ^b include a carbonyl group, a divalent hydrocarbon group, and a heterocyclic group. 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 linear hydrocarbon group and a branched hydrocarbon group that are composed only of a chain structure without including a cyclic structure in the main chain. However, it may be saturated or unsaturated. 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. “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.

In the specific silicon compound contained in the liquid crystal aligning agent of the present disclosure, “* 1” in the formula (1a) is further bonded to a hydrogen atom, a methylene group, or a monovalent hydrocarbon group, or It is a compound that satisfies at least one of having a hydroxy group in the molecule and R ^a in the above formula (1a) being ^a carbonyl group. By including such an organosilicon compound in the liquid crystal aligning agent, a liquid crystal alignment film having good rubbing resistance and resistance to external pressure can be obtained.

Here, when “* 1” in the formula (1a) is bonded to a methylene group, the methylene group forms at least a part of the ring structure together with the nitrogen atom and R ^b in the formula (1a). You may do it. The specific silicon compound has at least one nitrogen-containing structure represented by the above formula (1a), and “* 1” in the above formula (1a) is a hydrogen atom, a methylene group or a monovalent group. In the case of a compound bonded to a hydrocarbon group, the compound further satisfies at least one of having a hydroxy group in the molecule and that ^Ra in the formula (1a) is a carbonyl group. Also good.
As the specific silicon compound, from the viewpoint of sufficiently obtaining the effects of the present invention, among others, a group consisting of a silicon compound having a nitrogen-containing structure and a hydroxy group represented by the above formula (1a), and a silicon compound having a urea structure It is preferably at least one selected from

When the specific silicon compound is a silicon compound having a nitrogen-containing structure represented by the above formula (1a) and a hydroxy group, the compound is, for example, selected from the group consisting of a primary amino group and a secondary amino group And a reactive group having at least one reactive group selected from the group consisting of an acid anhydride group, an epoxy group, and an oxetanyl group. Examples thereof include compounds obtained by reacting compounds.
In addition, at least one of the amine compound and the reactive group-containing compound is a compound having a silicon atom. In this case, only one of the amine compound and the reactive group-containing compound may have a silicon atom, or both the amine compound and the reactive group-containing compound may have a silicon atom. Good.

Specific examples of the synthesis of the specific silicon compound by the reaction of the amine compound and the reactive group-containing compound include, for example, the following [1] to [4].
[1] A method in which a silicon compound (s-1) having a specific amino group is used as the amine compound and a compound (t-1) having an acid anhydride group is used as the reactive group-containing compound, and these are reacted;
[2] Method of reacting the amine compound with a silicon compound (s-2) having an acid anhydride group as the reactive group-containing compound [3] Having an epoxy group or an oxetanyl group as the reactive group-containing compound Method of reacting with amine compound using silicon compound (s-3) [4] Using silicon compound (s-1) having a specific amino group as the amine compound, epoxy group or oxetanyl as the reactive group-containing compound The method of making these react using the compound (e-1) which has group is mentioned.

  Examples of the silicon compound (s-1) used in the above [1] and [4] include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, and 3-amino. Propylmethyldimethoxysilane, 3-aminopropylethyldimethoxysilane, 3-aminopropylethyldiethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldiethylmethoxysilane, 3-aminopropyldiethylethoxysilane, N- (2 -Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, 4-amino Butyldimethylmethoxy Run, and the like. A silicon compound (s-1) can be used individually by 1 type in these or in mixture of 2 or more types.

  Examples of the silicon compound (s-2) used in the above formula [2] include trimethoxysilylpropyl succinic anhydride, triethoxysilylpropyl succinic anhydride, methyldimethoxysilylpropyl succinic anhydride, methyldiethoxysilyl. And propyl succinic anhydride. A silicon compound (s-2) can be used individually by 1 type or in mixture of 2 or more types.

で表される化合物などのオキセタニル基含有シラン化合物；などを挙げることができる。ケイ素化合物（ｓ−３）は１種を単独で又は２種以上を混合して使用することができる。 Examples of the silicon compound (s-3) having an epoxy group or oxetanyl group used in [3] above include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, and 3-glycidyloxy. Propylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyldimethylmethoxysilane, 3-glycidyloxypropyldimethylethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , Epoxy group-containing silane compounds such as 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane; the following formula (s-3-1)

An oxetanyl group-containing silane compound such as a compound represented by the formula: A silicon compound (s-3) can be used individually by 1 type or in mixture of 2 or more types.

  The compound (t-1) having an acid anhydride group used in the above [1] is not particularly limited as long as it has at least one acid anhydride group in one molecule. Specifically, as a compound having one acid anhydride group in one molecule, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, 2,3-pyridinecarboxylic acid anhydride, etc .; Examples of the compound having two or more acid anhydride groups include compounds exemplified as tetracarboxylic dianhydrides used for the synthesis of the polyamic acid. The compound (t-1) having an acid anhydride group can be used alone or in combination of two or more.

The amine compound used in the above [2] and [3] is not particularly limited as long as it has at least one specific amino group in one molecule. Specifically, as a compound having one primary amino group in one molecule, for example, aniline, cyclohexylamine, propylamine, butylamine, pentylamine, hexylamine, etc .; one secondary amino group in one molecule Examples of the compound having a group include dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di- (2-ethylhexyl). ) Amines, diallylamine, morpholine, etc .;
As compounds having two or more primary amino groups in one molecule, for example, compounds exemplified as diamines used for the synthesis of the polyamic acid, etc .; as compounds having two or more secondary amino groups in one molecule For example, piperazine and the like can be mentioned. The said amine compound can use these 1 type individually or in combination of 2 or more types.

  Examples of the compound (e-1) having an epoxy group or oxetanyl group used in the above [4] include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and 1,6-hexanediol diene. Glycidyl ether, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidyl-aminomethylcyclohexane, N, N-diglycidyl-cyclohexyl An amine etc. are mentioned. The said compound (e-1) can use these 1 type individually or in combination of 2 or more types.

The use ratio of the amine compound and the reactive group-containing compound used for the synthesis reaction of the specific silicon compound is such that the reactive group of the reactive group-containing compound is 0.2 to 1 equivalent to 1 equivalent of the specific amino group of the amine compound. A ratio of 2.5 equivalents is preferable, and a ratio of 0.3 to 2.2 equivalents is more preferable.
The reaction between the amine compound and the reactive group-containing compound is preferably performed in an organic solvent. The organic solvent used in the reaction may be any solvent that is inactive with respect to the amine compound and the reactive group-containing compound and can dissolve them, and examples thereof include N-methyl-2-pyrrolidone. . The reaction temperature is preferably 0 to 80 ° C, more preferably 10 to 70 ° C. The reaction time is preferably 1 to 60 hours, more preferably 10 to 30 hours.

（式（１）中、Ｒ^１９は水素原子若しくは１価の炭化水素基、又は分子内の２つのＲ^１９が結合して形成される２価の炭化水素基である。Ｒ^２０は３価の有機基であり、Ｒ^２１は２価の有機基であり、Ｒ^２２及びＲ^２３は、それぞれ独立に１価の炭化水素基であり、Ｒ^２４は（ｈ＋ｉ）価の有機基である。Ａ^１は単結合又はカルボニル基であり、Ａ^２は単結合、カルボニル基又は炭素数１〜３のアルカンジイル基であり、Ｂ^１及びＢ^２は、それぞれ独立にカルボニル基又は炭素数１〜３のアルカンジイル基である。ｅ、ｆ、ｇ及びｉはそれぞれ独立に０〜４の整数であり、ｅ＋ｆ＋ｇ≧１かつｅ＋ｉ≧１である。ｈは１〜４の整数であり、ｊは１〜３の整数である。ただし、Ｒ^２０、Ｒ^２２、Ｒ^２３、Ａ^１、Ａ^２、Ｂ^１及びＢ^２がそれぞれ複数存在する場合、複数のＲ^２０、Ｒ^２２、Ｒ^２３、Ａ^１、Ａ^２、Ｂ^１及びＢ^２は独立して上記定義を有する。） Specific examples of the specific silicon compound obtained by the above reaction include a compound represented by the following formula (1).

(In Formula (1), R ¹⁹ is a hydrogen atom, a monovalent hydrocarbon group, or a divalent hydrocarbon group formed by combining two R ¹⁹ in the molecule. R ²⁰ is a trivalent group. an organic ^{group, R 21} is a divalent organic ^{group, R 22} and ^{R 23} are each independently a monovalent hydrocarbon ^{group, R 24} is (h + i) -valent organic group .A ¹ Is a single bond or a carbonyl group, A ² is a single bond, a carbonyl group or an alkanediyl group having 1 to 3 carbon atoms, and B ¹ and B ² are each independently a carbonyl group or an alkane having 1 to 3 carbon atoms. E, f, g and i are each independently an integer of 0 to 4, e + f + g ≧ 1 and e + i ≧ 1, h is an integer of 1 to 4, and j is 1 to 3. An integer, where R ²⁰ , R ²² , R ²³ , A ¹ , A ² , B ¹ and B When a plurality of ² are present, a plurality of R ²⁰ , R ²² , R ²³ , A ¹ , A ² , B ¹ and B ² independently have the above definition.)

In the above formula (1), examples of the monovalent hydrocarbon group for R ¹⁹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. A linear or branched alkyl group; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group or a tolyl group; an aralkyl group such as a benzyl group; Among these, R ¹⁹ is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
In the case where R ¹⁹ there are two or more in one molecule, two R ¹⁹ in the molecule may constitute part of a ring bonded to each other. In this case, in the formula (1) ring is formed by ^{"-R 19} - nitrogen atom ^{-B 2 -R} 24 ^-B 2 - - nitrogen atom ^{-R 19".} The ring formed by the bond of R ¹⁹ is a nitrogen-containing heterocyclic ring having two nitrogen atoms, and examples thereof include a piperazine ring.

Examples of the trivalent organic group R ^20, for example, there are mentioned hydrocarbon group having 1 to 10 carbon atoms, preferably a chain hydrocarbon group having 1 to 3 carbon atoms. Examples of the divalent organic group represented by R ²¹ include a C 1-6 alkanediyl group or a divalent group in which a methylene group of the alkanediyl group is replaced with —O—.
Examples of the monovalent hydrocarbon group for R ²² and R ²³ include the groups exemplified as the monovalent hydrocarbon group for R ¹⁹ . Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group. Examples of R ²⁴ include a hydrocarbon group having 1 to 20 carbon atoms, a group in which the methylene group of the hydrocarbon group is replaced by —O—, —CO—, —COO—, —NH—, —NHCO—, etc. Examples include a group in which a hydrogen atom of a hydrogen group is substituted with a halogen atom (preferably a fluorine atom).

When e = 0, it is preferable that at least one of B ¹ and B ² is a carbonyl group, and A ¹ is a carbonyl group. In this case, the specific silicon compound has a structure in which the hydroxy group and the nitrogen-containing structure of the specific silicon compound are respectively bonded to the carbonyl group. In addition, when the hydroxy group is bonded to the carbonyl group, the specific silicon compound has a carboxyl group, and when the nitrogen-containing structure is bonded to the carbonyl group, the specific silicon compound is an amide bond (—CO—NR—). Have However, the specific silicon compound may further have a hydroxy group in addition to the carboxyl group, and may further have —NR— in addition to the amide bond.

  Specific examples of the compound represented by the above formula (1) include compounds represented by the following formulas (1-1) to (1-5).

（式（１−１）中、Ｒ^１は４価の有機基であり、Ｒ^２は２価の有機基であり、Ｒ^３及びＲ^４は、それぞれ独立に１価の炭化水素基であり、ａは１〜３の整数である。ただし、複数のＲ^２は同じでも異なっていてもよい。Ｒ^３及びＲ^４がそれぞれ複数存在する場合、複数のＲ^３及び複数のＲ^４は同じでも異なっていてもよい。）

(In Formula (1-1), R ¹ is a tetravalent organic group, R ² is a divalent organic group, R ³ and R ⁴ are each independently a monovalent hydrocarbon group, a is an integer of 1 to 3. However, when a plurality of R ² is the optionally be the same or different .R ³ and R ⁴ are present in plural, even the plurality of R ³ and plural R ⁴ are the same or different May be.)

（式（１−２）中、Ｒ^５及びＲ^７は、それぞれ独立に２価の有機基であり、Ｒ^６は３価の有機基であり、Ｒ^８及びＲ^９はそれぞれ独立に１価の炭化水素基であり、ｂは１〜３の整数である。ただし、複数のＲ^６は同じでも異なっていてもよい。Ｒ^８及びＲ^９がそれぞれ複数存在する場合、複数のＲ^８及び複数のＲ^９は同じでも異なっていてもよい。）

(In Formula (1-2), R ⁵ and R ⁷ are each independently a divalent organic group, R ⁶ is a trivalent organic group, and R ⁸ and R ⁹ are each independently monovalent. a hydrocarbon group, b is an integer of 1-3. However, the plurality R ⁶ If the good .R ⁸ and R ⁹ may be the same or different are present in plural, a plurality of R ⁸ and a plurality of R ⁹ may be the same or different.)

（式（１−３）中、Ｒ^１０及びＲ^１１はそれぞれ独立に２価の有機基であり、Ｒ^１２及びＲ^１３はそれぞれ独立に１価の炭化水素基であり、ｃは１〜３の整数である。ただし、Ｒ^１２及びＲ^１３がそれぞれ複数存在する場合、複数のＲ^１２及び複数のＲ^１３は同じでも異なっていてもよい。）

(In formula (1-3), R ¹⁰ and R ¹¹ are each independently a divalent organic group, R ¹² and R ¹³ are each independently a monovalent hydrocarbon group, and c is 1 to 3. (However, when there are a plurality of R ¹² and R ¹³ , respectively, the plurality of R ¹² and the plurality of R ¹³ may be the same or different.)

（式（１−４）中、Ｒ^１４は１価の有機基であり、Ｒ^１５は３価の有機基であり、Ｒ^１６は２価の炭化水素基であり、Ｒ^１７及びＲ^１８はそれぞれ独立に１価の炭化水素基であり、ｄは１〜３の整数である。ただし、Ｒ^１７及びＲ^１８がそれぞれ複数存在する場合、複数のＲ^１７及び複数のＲ^１８は同じでも異なっていてもよい。）

(In the formula (1-4), R ¹⁴ is a monovalent organic group, R ¹⁵ is a trivalent organic group, R ¹⁶ is a divalent hydrocarbon group, and R ¹⁷ and R ¹⁸ are respectively independently a monovalent hydrocarbon group, d is an integer of 1-3. ^{However, if R 17} and ^{R 18} are present in plural, plural ^{R 17} and plural ^{R 18} are either the same or different May be.)

（式（１−５）中、Ｒ^２５は水素原子若しくは１価の炭化水素基、又は分子内の２つのＲ^２５が結合して形成される２価の炭化水素基である。Ｒ^２６は２価の有機基であり、Ｒ^２７は３価の有機基であり、Ｒ^３０は２価の有機基であり、Ｒ^２８及びＲ^２９はそれぞれ独立に１価の炭化水素基であり、ｋは１〜３の整数である。Ａ^３は単結合、カルボニル基又は炭素数１〜３のアルカンジイル基である。ただし、分子内に存在する複数のＲ^２５、Ｒ^２７、Ｒ^３０及びＡ^３は、互いに同じでも異なってもよい。Ｒ^２８及びＲ^２９がそれぞれ複数存在する場合、複数のＲ^２８及び複数のＲ^２９は同じでも異なっていてもよい。）

(In Formula (1-5), R ²⁵ is a hydrogen atom, a monovalent hydrocarbon group, or a divalent hydrocarbon group formed by combining two R ²⁵ in the molecule. R ²⁶ is 2 R ²⁷ is a trivalent organic group, R ³⁰ is a divalent organic group, R ²⁸ and R ²⁹ are each independently a monovalent hydrocarbon group, and k is 1 A ³ is a single bond, a carbonyl group or an alkanediyl group having 1 to 3 carbon atoms, provided that a plurality of R ²⁵ , R ²⁷ , R ³⁰ and A ³ present in the molecule are And may be the same or different from each other. When there are a plurality of R ²⁸ and R ²⁹ , the plurality of R ²⁸ and the plurality of R ²⁹ may be the same or different.)

The compound represented by the above formula (1-1) can be synthesized by the method of [1], specifically, an amino group-containing silane compound and an acid anhydride as the silicon compound (s-1). It can be obtained by using tetracarboxylic dianhydride as the compound (t-1) having a group and reacting them.
Here, in the above formula (1-1), the tetravalent organic group of R ¹ is a tetravalent group derived from tetracarboxylic dianhydride. The divalent organic group of R ^{2 is} a divalent group derived from an amino group-containing silane compound. For example, an alkanediyl group having 1 to 6 carbon atoms, and —NH— between the carbon-carbon bonds of the alkanediyl group. And a divalent group having.
Examples of the monovalent hydrocarbon group for R ³ and R ⁴ include the groups exemplified as the monovalent hydrocarbon group for R ^{19 in} the above formula (1). Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group.

The compound represented by the above formula (1-2) can be synthesized by the method of [2] above. Specifically, an acid anhydride group-containing silane compound as the silicon compound (s-2), and the above It can be obtained by using diamine as the amine compound and reacting them.
Here, in the above formula (1-2), the divalent organic group represented by R ⁵ is a divalent group derived from diamine. The divalent organic group of R ^{7 is} a divalent organic group derived from an acid anhydride group-containing silane compound, and examples thereof include an alkanediyl group having 1 to 6 carbon atoms. Examples of the trivalent organic group for R ⁶ include a chain hydrocarbon group having 1 to 5 carbon atoms. Examples of the monovalent hydrocarbon group for R ⁸ and R ⁹ include the groups exemplified as the monovalent hydrocarbon group for R ^{19 in} the above formula (1). Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group.

The compound represented by the above formula (1-3) can be synthesized by the method of [1], specifically, an amino group-containing silane compound and an acid anhydride as the silicon compound (s-1). It can be obtained by using acid monoanhydride as the compound (t-1) having a group and reacting them.
Here, in the above formula (1-3), the divalent organic group represented by R ¹⁰ is a divalent group derived from an acid monoanhydride, such as a divalent hydrocarbon group having 2 to 20 carbon atoms. Is mentioned. The divalent organic group of R ^{11 is} a divalent group derived from an amino group-containing silane compound. For example, an alkanediyl group having 1 to 6 carbon atoms, and —NH— between the carbon-carbon bonds of the alkanediyl group. And a divalent group having.
Examples of the monovalent hydrocarbon group for R ¹² and R ¹³ include the groups exemplified as the monovalent hydrocarbon group for R ^{19 in} the above formula (1). Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group.

The compound represented by the above formula (1-4) can be synthesized by the method of [2], specifically, an acid anhydride group-containing silane compound as the silicon compound (s-2), and the above It can be obtained by using monoamines as amine compounds and reacting them.
Here, in the above formula (1-4), the monovalent organic group of R ¹⁴ is a monovalent group derived from monoamine. Examples of the trivalent organic group for R ¹⁵ include a chain hydrocarbon group having 1 to 5 carbon atoms. The divalent organic group of R ^{16 is} a divalent organic group derived from an acid anhydride group-containing silane compound, and examples thereof include an alkanediyl group having 1 to 6 carbon atoms. Examples of the monovalent hydrocarbon group for R ¹⁷ and R ¹⁸ include the groups exemplified as the monovalent hydrocarbon group for R ^{19 in} the above formula (1). Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group.

The compound represented by the above formula (1-5) can be synthesized by the method of [3], specifically, an epoxy group-containing silane compound or an oxetanyl group-containing silane as the silicon compound (s-3). It can be obtained by reacting a compound and the compound exemplified above as the amine compound.
Here, in the above formula (1-5), the divalent organic group represented by R ²⁶ is a divalent group derived from an amine compound. Examples of the trivalent organic group represented by R ²⁷ include a chain hydrocarbon group having 1 to 5 carbon atoms. The divalent organic group of R ^{30 is} a divalent group derived from an epoxy group-containing silane compound or an oxetanyl group-containing silane compound, such as an alkanediyl group having 1 to 5 carbon atoms or a carbon-carbon of the alkanediyl group. And a divalent group having —O— between the bonds. Examples of the monovalent hydrocarbon group for R ²⁵ , R ²⁸ and R ²⁹ include the groups exemplified as the monovalent hydrocarbon group for R ^{19 in} the above formula (1). Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group. A ³ is preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms.

（式（２）中、Ｒ^３１及びＲ^３２は、それぞれ独立に１価の炭化水素基であり、Ｒ^３３は２価の有機基であり、Ｒ^３４は１価の有機基である。ｔは１〜３の整数である。ただし、Ｒ^３１、Ｒ^３２が複数存在する場合、複数のＲ^３１、Ｒ^３２は独立して上記定義を有する。） Preferable specific examples in the case where the specific silicon compound is a silicon compound having a urea structure include, for example, a compound represented by the following formula (2).

(In Formula (2), R ³¹ and R ³² are each independently a monovalent hydrocarbon group, R ³³ is a divalent organic group, and R ³⁴ is a monovalent organic group. 1-3 is an integer. ^However, if R ^{31, R 32} there are a plurality, a plurality of ^{R 31, R 32} have the above defined independently.)

In the above formula (2), R ³¹ and R ³² are preferably a methyl group or an ethyl group. Examples of R ³³ include a C1-C6 alkanediyl group or a divalent group in which a methylene group of the alkanediyl group is replaced with —O—. Examples of R ³⁴ include a monovalent hydrocarbon group and a monovalent alicyclic group.
Specific examples of the compound represented by the above formula (2) include, for example, 1- (pyridin-2-yl) -3- (3-triethoxysilyl) propyl) urea, 1- (pyridin-2-yl)- 3- (3-trimethoxysilyl) propyl) urea, 1- (pyridin-2-yl) -3- (3-methyldiethoxysilyl) propyl) urea and the like. In addition, as a silicon compound which has a urea structure, 1 type can be used individually or in combination of 2 or more types.

  As the specific silicon compound contained in the liquid crystal aligning agent of the present disclosure, among the above, at least one selected from the group consisting of the compound represented by the above formula (1) and the compound represented by the above formula (2) is particularly preferable. It can be preferably used. In addition, a specific silicon compound can be used individually by 1 type or in combination of 2 or more types.

  The blending ratio of the specific silicon compound is preferably 0.01 to 50 parts by weight with respect to 100 parts by weight of the total polymer components of the liquid crystal aligning agent. This is because if the amount is less than 0.01 part by weight, the improvement effect due to the addition of the organosilicon compound is difficult to obtain, and if the amount exceeds 50 parts by weight, the liquid crystal orientation tends to decrease. More preferably, it is 0.05-40 weight part, More preferably, it is 0.1-35 weight part, Especially preferably, it is 0.1-30 weight part. In addition, a specific silicon compound can be used individually by said 1 type or in combination of 2 or more types.

<Other ingredients>
The liquid crystal aligning agent of this indication may contain other components other than a polymer (P) and a specific silicon compound as needed. Examples of the other components include polymers other than polyamic acid, polyimide and polyamic acid ester, compounds having at least one epoxy group in the molecule (hereinafter referred to as “epoxy group-containing compound”), and specific silicon compounds. Other functional silane compounds other than 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 polymers having a main skeleton of polyorganosiloxane, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, poly (meth) acrylate, and the like. It is done.
When adding another polymer to a liquid crystal aligning agent, it is preferable that the mixture ratio shall be 50 weight part or less with respect to a total of 100 weight part of the polymer contained in a liquid crystal aligning agent, The amount is more preferably 40 parts by weight, and still 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 and electrical properties with the substrate surface in the liquid crystal alignment film. 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-xylylene diene Amine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diamy Diphenylmethane, N, N-diglycidyl - benzylamine, N, N-diglycidyl - aminomethyl cyclohexane, N, N-diglycidyl - may be mentioned as being preferred and cyclohexylamine. In addition, as an example of the epoxy group-containing compound, an epoxy group-containing polyorganosiloxane described in International Publication No. 2009/096598 can be used.
When adding an epoxy group containing compound to a liquid crystal aligning agent, it is preferable that the mixture ratio shall be 40 weight part or less with respect to a total of 100 weight part of the polymer contained in a liquid crystal aligning agent. More preferably, it is 30 parts by weight.

[Other functional silane compounds]
Other functional silane compounds 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 other functional silane compounds are added to the liquid crystal aligning agent, the blending ratio is preferably 2 parts by weight or less with respect to a total of 100 parts by weight of the polymer contained in the liquid crystal aligning agent. It is more preferable to set it as 02-0.2 weight part.

  As other components, in addition to the above, compounds having at least one oxetanyl group in the molecule, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, sensitizers, etc. Can be mentioned.

<Solvent>
The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition in which the polymer (P), the specific silicon compound and other components used as necessary are preferably dispersed or dissolved in an appropriate solvent. The

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

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

<Liquid crystal display element>
The liquid crystal display element of this indication comprises the liquid crystal aligning film formed using the liquid crystal aligning agent demonstrated above. The operation mode of the liquid crystal display element is not particularly limited, and for example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend) type. It can be applied to various operation modes.

  A liquid crystal display element can be manufactured by the method including the following processes (1)-(3), for example. In step (1), the substrate to be used varies depending on the desired operation mode. Step (2) and step (3) are common to each operation mode.

[Step (1): Formation of coating film]
First, a liquid crystal aligning agent is apply | coated on a board | substrate, Then, a coating film is formed on a board | substrate by heating an application surface.
(1-A) For example, when manufacturing a TN type, STN type, or VA type liquid crystal display element, first, a pair of two substrates provided with patterned transparent conductive films is formed, and each transparent conductive film is formed. On the surface, a liquid crystal aligning agent 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, an NESA film (US PPG, registered trademark) 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. 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 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. Thereafter, the solvent is completely removed, and if necessary, a baking (post-baking) step is performed for the purpose of thermally imidizing 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-B) When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb shape, and an electrode are provided. A liquid crystal aligning agent is apply | coated to one surface of the counter substrate which is not formed, respectively, Then, each coating surface is heated and a coating film is formed. Regarding the material used for the substrate and the transparent conductive film, the coating method, the heating conditions after coating, the patterning method for the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the coating film to be formed Same as (1-A). As the metal film, for example, a film made of a metal such as chromium can be used.

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

[Step (2): Orientation ability imparting treatment]
When manufacturing a TN type, STN type, IPS type, or FFS type liquid crystal display element, the process which provides liquid crystal aligning ability to the coating film formed at the said process (1) is implemented. Thereby, the orientation ability of liquid crystal molecules is imparted to the coating film to form a liquid crystal orientation film. The alignment ability imparting treatment includes a rubbing treatment in which the coating film is rubbed in a fixed direction with a roll wound with a fiber made of, for example, nylon, rayon, or cotton, and light that irradiates the coating film with polarized or non-polarized radiation. An alignment process etc. are mentioned. In particular, the liquid crystal alignment film formed with the liquid crystal aligning agent has high rubbing resistance, and even when the rubbing treatment is adopted as the alignment ability imparting treatment, scratches and film peeling hardly occur. On the other hand, when manufacturing a VA type liquid crystal display element, the coating film formed in the above step (1) can be used as it is as a liquid crystal alignment film, but even if the coating film is subjected to alignment ability imparting treatment. Good.

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

[Step (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 to a predetermined location 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 sealing agent, thereby Can be manufactured. Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the used liquid crystal 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 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 a liquid crystal display element can be obtained by sticking a polarizing plate on the outer surface of a liquid crystal cell. As a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing film or an H film itself in which a polarizing film called an “H film” in which iodine is absorbed while stretching and aligning polyvinyl alcohol is sandwiched between cellulose acetate protective films The polarizing plate which consists of can be mentioned.

  The liquid crystal display element of the present disclosure can be effectively applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, cellular phones, smartphones, It can be used for various display devices such as tablet PCs, various monitors, liquid crystal televisions, and information displays.

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

In the following synthesis examples, the weight average molecular weight Mw and imidization rate of the polymer, and the solution viscosity of the polymer solution were measured by the following methods. Hereinafter, the compound represented by Formula X may be simply referred to as “Compound X”.
[Weight average molecular weight Mw of polymer]
Mw is a polystyrene equivalent value measured by GPC under the following conditions.
Column: Tosoh Co., Ltd., TSKgelGRCXLII
Solvent: Tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Imidation rate of polymer]
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.

<Synthesis of organosilicon compounds>
[Synthesis Example 1-1; Synthesis of Compound (Si-1)]
3-aminopropyltriethoxysilane (APTES) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB) were mixed with N-methyl-2 at a blend ratio of APTES: CB = 2: 1 (molar ratio). -In addition to pyrrolidone (NMP), the mixture was stirred and reacted at 25 ° C for 6 hours to obtain a solution containing the compound (Si-1) as an organosilicon compound.

[Synthesis Example 1-2 to Synthesis Example 1-6]
Except that the compounds (precursors) used in the reaction and the blending ratios thereof were changed as shown in Table 1 below, compounds (Si-2) to compounds (Si A solution containing -6) was obtained.

In Table 1, the abbreviations of the precursors are as follows.
(Precursor 1; Silane compound)
C-1; 3-aminopropyltriethoxysilane (APTES)
C-2; 3-trimethoxysilylpropyl succinic anhydride C-3; 3-glycidyloxypropyltrimethoxysilane (precursor 2; other compounds)
AN-1; pyromellitic dianhydride AN-2; 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB)
DA-1; p-phenylenediamine B-1; maleic anhydride B-2; 2,3-pyridinedicarboxylic anhydride B-3; piperazine

<Synthesis of polymer>
[Synthesis Example 2-1; Synthesis of Polymer (PAA-1)]
100 mol parts of pyromellitic dianhydride as tetracarboxylic dianhydride, and 100 mol parts of bis [2- (4-aminophenyl) ethyl] hexanedioic acid as diamine, N-methyl-2-pyrrolidone (NMP) And a reaction was performed at 60 ° C. for 6 hours to obtain a polyamic acid solution having a solid concentration of 15% by weight. A small amount of the obtained polyamic acid solution was collected, and the measured solution viscosity was 420 mPa · s.

[Synthesis Example 2-2 to Synthesis Example 2-7]
In the above Synthesis Example 2-1, the polyamic acid was used in the same manner as in Synthesis Example 2-1, except that the types and amounts of tetracarboxylic dianhydride and amine (diamine and monoamine) used in the reaction were changed as shown in Table 2 below. Got. In addition, about the synthesis example 2-2 to the synthesis example 2-7, the numerical value of Table 2 shows the use ratio (mol part) with respect to 100 mol parts of the whole quantity of the tetracarboxylic dianhydride used for reaction.

Abbreviations of tetracarboxylic dianhydride and diamine in Table 2 are as follows.
(Tetracarboxylic dianhydride)
AN-1; pyromellitic dianhydride AN-2; 1,2,3,4-cyclobutanetetracarboxylic dianhydride AN-3; 2,3,5-tricarboxycyclopentylacetic acid dianhydride AN-4; Bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic acid 2: 4,6: 8-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; 1,3-propylene glycol bis (anhydrotrimellitate)
AN-7; dimethyl-1,3-bis (chlorocarbonyl) cyclobutane-2,4-carboxylate AN-8; dimethyl-1,3-bis (chlorocarbonyl) cyclopentane-2,4-carboxylate

(Diamine)
P-phenylenediamine DA-2; 4,4′-diaminodiphenylmethane DA-3; 4,4′-diaminodiphenylamine DA-4; 1,5-bis (4-aminophenoxy) pentane DA-5; 4-aminophenyl-4′-aminobenzoate DA-6; bis [2- (4-aminophenyl) ethyl] hexanedioic acid DA-7; 2,2′-bis (trifluoromethyl) -4,4′- Diaminobiphenyl DA-8; 4,4′-diaminotriphenylamine DA-9; compound DA-10 represented by the following formula (DA-9); 4- (tetradecaoxy) benzene-1,3-diamine DA -11; stearylamine DA-12; 1,3-bis (3-aminopropyl) -tetramethyldisiloxane DA-13; 3,6-bis (4-aminobenzoylo Xyl) cholestane DA-14; compound DA-15 represented by the following formula (DA-14); compound represented by the following formula (DA-15)

[Synthesis Example 2-8; Synthesis of Polymer (PI-8)]
100 mol parts of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic dianhydride, and 80 mol parts of p-phenylenediamine, 10 mol parts of 4,4′-diaminodiphenylmethane as diamine, and 2, 10 mol parts of 2′-bis (trifluoromethyl) -4,4′-diaminobiphenyl was dissolved in NMP and reacted at room temperature for 6 hours to obtain a polyamic acid solution having a solid content concentration of 15% by weight. NMP was added to this polyamic acid solution to a solid content concentration of 10% by weight, and 200 mol parts of pyridine and acetic anhydride were added to each of 100 mol parts of tetracarboxylic dianhydride for 4 hours at 110 ° C. A dehydration ring closure reaction was performed. After the dehydration ring-closing reaction, the solvent in the system was replaced with new NMP to obtain a solution containing polyimide (polymer (PI-8)) having an imidization rate of 75%. It was 520 mPa * s when the viscosity of the solution which adjusted the obtained polymer (PI-8) so that it might become 15 weight% with NMP was measured.

[Synthesis Example 2-9; Synthesis of Polymer (PI-9)]
In Synthesis Example 2-8, the types and amounts of tetracarboxylic dianhydride and diamine used in the reaction and the amounts of pyridine and acetic anhydride were changed as shown in Table 2 above, and were the same as those of Synthesis Example 2-9. By performing the operation, polyimide (polymer (PI-9)) was obtained. In addition, about the synthesis example 2-9, the numerical value of Table 2 shows the use ratio (mol part) with respect to 100 mol parts of the whole quantity of the tetracarboxylic dianhydride used for reaction. It was 520 mPa * s when the viscosity of the solution which adjusted the obtained polymer (PI-9) so that it might become 15 weight% with NMP was measured.

[Synthesis Example 2-10; Synthesis of Polymer (PAE-10)]
As the diamine, 6.92 g of p-phenylenediamine (80 mol parts relative to 100 mol parts of the total amount of diamine used in the synthesis), 3.17 g (20 mol parts) of 4,4′-diaminodiphenylmethane, and 15 ml of pyridine and 505 ml of N-methyl-2-pyrrolidone (NMP) was 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, the polymer is collected by suction filtration, washed again with 250 g of water, washed 3 times with 63 g of methanol, and dried under reduced pressure at 40 ° C. Thus, 28 g of polyamic acid ester powder was obtained. The weight average molecular weight of this polyamic acid ester (polymer (PAE-10)) was Mw = 27,000. In addition, about the synthesis example 2-10, the numerical value of Table 2 shows the usage-amount (mol part) with respect to 100 mol part of the whole quantity of the tetracarboxylic acid derivative used for reaction about the tetracarboxylic acid derivative, About diamine, The ratio of use (mole parts) to the total amount of 100 parts by mole of diamine used in the reaction is shown.

[Synthesis Example 2-11; Synthesis of Polymer (PAE-11)]
In Synthesis Example 2-10, similar to Synthesis Example 2-10 except that the types and amounts of tetracarboxylic acid diester dihalide and diamine used in the reaction and the amounts of pyridine and acetic anhydride were changed as shown in Table 2 above. By performing the operation, a polyamic acid ester (polymer (PAE-11)) was obtained. For Synthesis Example 2-11, the numerical values in Table 2 are synonymous with those of Synthesis Example 2-10.

<Preparation and evaluation of liquid crystal aligning agent>
[Example 1]
(1) Preparation of liquid crystal aligning agent 100 parts by weight of polymer (PAA-1) obtained in Synthesis Example 2-1 as a polymer, and compound (Si-1) 2 obtained in Synthesis Example 1-1 as an organosilicon compound A weight part is melt | dissolved in the mixed solvent (GBL: NMP: DEDG = 55: 30: 15 (weight ratio)) which consists of (gamma) -butyrolactone (GBL), NMP, and diethylene glycol diethyl ether (DEDG), and solid content concentration is 6. The solution was 0% 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) Evaluation of rubbing resistance Using the liquid crystal aligning agent prepared in the above (1), a coating film was formed on a quartz substrate, and then a rubbing apparatus provided with a roll wound with a rayon cloth was used. The rubbing treatment was performed under the two conditions described in 3 (condition (A) and condition (B)). The coating film (liquid crystal alignment film) after the rubbing treatment was washed with isopropyl alcohol, and the presence or absence of peeling of the alignment film from the substrate and rubbing damage was visually confirmed. At this time, when neither peeling of the liquid crystal alignment film nor rubbing scratch was observed, rubbing resistance “good” (◯), and when at least one of peeling of the liquid crystal alignment film or rubbing scratch was observed, “bad” X) ". As a result, in this example, peeling of the liquid crystal alignment film and rubbing scratches were not observed in any of the conditions (A) and (B), and the rubbing resistance was “good”.

(3) Manufacture of liquid crystal cell The liquid crystal aligning agent prepared in the above (1) is applied to a liquid crystal alignment film printer (Nissha Printing (Nissha Printing) on the electrode surface of a 1 mm thick glass substrate having ITO electrodes provided in a comb shape. The product is applied on a hot plate at 80 ° C. for 1 minute (pre-baked) to remove the solvent, and then heated on a hot plate at 200 ° C. for 10 minutes (post-bake) to obtain an average film. A coating film having a thickness of 0.06 μm was 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. In addition, the above operation is repeated for a glass substrate having a thickness of 5 μm and a circular photospacer having a diameter of 5 μm dispersed at an area ratio of 0.1% and having a thickness of 1 mm and having no electrode, thereby having a liquid crystal alignment film. A pair (two) of substrates was obtained.
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-2042, 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 photocurable adhesive to produce a liquid crystal cell.

(4) Evaluation of defective bright spot of liquid crystal cell Using a push-pull gauge (manufactured by Imada Co., Ltd.), a pressure was applied to the central portion of the liquid crystal cell produced in the above (3) for 5 seconds so as to be 40 N. This process was repeated 100 times. “Good (◯)” when no bright spot was observed with a polarizing microscope, “Yes (Δ)” when 1 to 9 bright spots were observed, and 10 bright spots. The case where it was observed above was defined as “defective (×)”. As a result, no bright spot was observed in this example, and the result was “good”.

(5) Evaluation of liquid crystal alignment A
Regarding the liquid crystal cell produced in (3) above, the presence or absence of abnormal domains in the change in brightness when observing the presence or absence of flow alignment of liquid crystals with a polarizing microscope and repeatedly turning on and off (applying and releasing) the voltage of 5 V The liquid crystal orientation was evaluated by observing the film with a polarizing microscope. In the evaluation, when neither flow alignment nor abnormal domain was observed, the liquid crystal alignment was “good (◯)”, and when flow alignment was not observed, but abnormal domain was observed “OK” (△) A case where orientation was observed was defined as “bad (×)”. As a result, the liquid crystal orientation of this example was evaluated as “good”.

(6) Evaluation of liquid crystal alignment B (resistance to seizure at high temperature)
Two liquid crystal cells are prepared by the above method (3), one of which (element A) has an AC voltage of 10 V, the other (element B) has an AC voltage of 1 V, respectively, under the backlight. Application was performed at 60 ° C. for 20 hours. Thereafter, the luminance difference between the element A and the element B observed when the voltage application was switched to the DC voltage of 2.5 V was expressed by 256 gradations, and the burn-in resistance under a high temperature environment was evaluated by the luminance difference. When the luminance difference was less than 5, the burn-in resistance was “good”. When the brightness difference was 5 or more and less than 10, the burn-in resistance was “good”. As a result, in this example, the seizure resistance was “good”.

(7) Electrical characteristics evaluation (voltage holding ratio)
About the liquid crystal cell manufactured by the method of (3) above, after applying a voltage of 5 V at 40 ° C. with an application time of 60 microseconds and a span of 167 milliseconds, the voltage holding ratio (VHR) after 167 milliseconds from the release of application ) Was measured. In addition, as a measuring apparatus, Toyo Technica Co., Ltd. make and VHR-1 were used. The electrical characteristics of the liquid crystal cell are evaluated as “good” when the voltage holding ratio is 98% or more, “good” when the voltage holding ratio is 95% or more and less than 98%, and “bad” when the voltage holding ratio is 95% or less. " As a result, in this example, the electrical property was “good”.

[Examples 2 to 12 and Comparative Examples 1 to 5]
In Example 1 above, except that the types and amounts of the polymers and additives used were as shown in Table 4 below, preparation of the liquid crystal aligning agent and production of the liquid crystal cell were conducted in the same manner as in Example 1, Evaluation was performed. The evaluation results are shown in Table 4 below.

In Table 4, the abbreviations of the additives are as follows.
Add-1, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane Add-2; 3-glycidyloxypropyltrimethoxysilane Add-3; 3-aminopropyltriethoxysilane Si-7 Compound represented by the following formula (si-7)

  As shown in Table 4, in the liquid crystal aligning agents of Examples 1 to 12 containing the organosilicon compound having the nitrogen-containing structure represented by the above formula (1a), the rubbing resistance of the liquid crystal alignment film formed using the same Was good. In addition, the liquid crystal cells of Examples 1 to 12 are “good” in terms of resistance to bright spot defects, evaluation of liquid crystal alignment (fluid alignment of liquid crystals and presence / absence of abnormal domains), burn-in resistance at high temperatures, and electrical characteristics. "Or" Yes ", and various characteristics were balanced. On the other hand, in the comparative example, it was inferior to the thing of an Example by the rubbing tolerance of a liquid crystal aligning film, the difficulty of generating the bright spot defect in a liquid crystal cell, and / or liquid crystal orientation.

Claims (6)

At least one polymer (P) selected from the group consisting of polyamic acid, polyamic acid ester and polyimide;
A liquid crystal aligning agent comprising an organosilicon compound represented by the following formula (1) (excluding a compound represented by the following formula (3)).

(In Formula (1), R ¹⁹ is a hydrogen atom, a monovalent hydrocarbon group, or a divalent hydrocarbon group formed by combining two R ¹⁹ in the molecule. R ²⁰ is a trivalent group. an organic ^{group, R 21} is a divalent organic ^{group, R 22} and ^{R 23} are each independently a monovalent hydrocarbon ^{group, R 24} is (h + i) -valent organic group .A ¹ Is a single bond or a carbonyl group, A ² is a single bond, a carbonyl group or an alkanediyl group having 1 to 3 carbon atoms, and B ¹ and B ² are each independently a carbonyl group or an alkane having 1 to 3 carbon atoms. E, f, g and i are each independently an integer of 0 to 4, e + f + g ≧ 1 and e + i ≧ 1, h is an integer of 1 to 4, and j is 1 to 3. An integer, where R ²⁰ , R ²² , R ²³ , A ¹ , A ² , B ¹ and B When a plurality of ² are present, a plurality of R ²⁰ , R ²² , R ²³ , A ¹ , A ² , B ¹ and B ² independently have the above definition.)

The organosilicon compound comprises an amine compound having at least one selected from the group consisting of a primary amino group and a secondary amino group, and at least one selected from the group consisting of an acid anhydride group, an epoxy group and an oxetanyl group. A compound obtained by reacting a reactive group-containing compound with
The liquid crystal aligning agent of Claim 1 whose at least any one of the said amine compound and the said reactive group containing compound is a compound which has a silicon atom. The organosilicon compound has a hydroxy group;
The liquid crystal aligning agent of Claim 1 or 2 with which at least 1 of the hydroxy group which the said organosilicon compound has couple | bonded with the carbonyl group.   The liquid crystal aligning agent as described in any one of Claims 1-3 whose compounding ratio of the said organosilicon compound is 0.1-30 weight part with respect to 100 weight part of the said polymer (P).   The liquid crystal aligning film formed using the liquid crystal aligning agent as described in any one of Claims 1-4.   A liquid crystal display device comprising the liquid crystal alignment film according to claim 5.