JPWO2016068085A1 - Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element - Google Patents

Abstract

Provided are a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element for obtaining a counter film suitable for photo-alignment that does not generate a bright spot even in a negative liquid crystal and can obtain good afterimage characteristics. At least one heavy selected from the group consisting of a polyimide precursor having a structural unit represented by formula (1) and a structural unit represented by formula (2) and an imidized polymer of the polyimide precursor. A liquid crystal aligning agent containing a combination (A). [Chemical Formula 1] (X1, X2: Formula (X1-1) or (X1-2), R1, R2, R3, R4, and R6 each independently represents a hydrogen atom or an alkyl having 1 to 4 carbon atoms. R5 is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 6.) [Chemical Formula 2]

Description

  The present invention relates to a liquid crystal aligning agent suitable for a photo-alignment method treatment, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the liquid crystal aligning film.

  In a liquid crystal display element used for a liquid crystal television, a liquid crystal display, and the like, a liquid crystal alignment film for controlling the alignment state of liquid crystals is usually provided in the element. As the liquid crystal alignment film, a polyimide liquid crystal alignment film obtained by applying a liquid crystal alignment agent mainly composed of a polyimide precursor such as polyamic acid (polyamic acid) or a solution of soluble polyimide to a glass substrate or the like and baking it is mainly used. ing. At present, according to the most widespread industrial method, this liquid crystal alignment film is rubbed in one direction with a cloth of cotton, nylon, polyester or the like on the surface of the polyimide liquid crystal alignment film formed on the electrode substrate. It is produced by performing a so-called rubbing process.

The photo-alignment method has an advantage that it can be produced by a simple manufacturing process industrially as an alignment treatment method without rubbing.
In an IPS (In Plane Switching) driving method or FFS (Fringe Field switching) driving type liquid crystal display element, a liquid crystal alignment film obtained by a photo-alignment method is used, compared with a liquid crystal alignment film obtained by a rubbing treatment method. Since it is possible to improve the performance of the liquid crystal display element such that the contrast and viewing angle characteristics of the liquid crystal display element can be expected to improve, the liquid crystal display element is attracting attention as a promising liquid crystal alignment treatment method.

  However, the liquid crystal alignment film obtained by the photo-alignment method has a problem that anisotropy with respect to the alignment direction of the polymer film is smaller than that by the rubbing process. If the anisotropy is small, sufficient liquid crystal orientation cannot be obtained, and problems such as occurrence of afterimages occur when a liquid crystal display element is formed. As a method for increasing the anisotropy of a liquid crystal alignment film obtained by a photo-alignment method, it has been proposed to remove a low molecular weight component generated by cutting the main chain of the polyimide by light irradiation after light irradiation.

Japanese Unexamined Patent Publication No. 9-297313 Japanese Unexamined Patent Publication No. 2011-107266

"Liquid crystal alignment film", Functional materials, November 1997, Vol. 17, No. 11 Pages 13-22

In the IPS drive type and FFS drive type liquid crystal display elements, a positive type liquid crystal is conventionally used. By using a negative type liquid crystal, it is possible to reduce the transmission loss at the upper part of the electrode and improve the contrast. It is. When the liquid crystal alignment film obtained by the photo-alignment method is used for an IPS driving type or FFS driving type liquid crystal display element using a negative liquid crystal material, it is expected to have higher display performance than a conventional liquid crystal display element.
However, as a result of studies by the present inventors, the liquid crystal alignment film obtained by the photo-alignment method has a high incidence of display defects (bright spots) in the case of a liquid crystal display element using a negative liquid crystal material and causes display defects. I found out there was a problem.

  An object of the present invention is to provide a liquid crystal suitable for a photo-alignment method treatment for obtaining a liquid crystal alignment film for a photo-alignment method, in which a bright spot is not generated even when a negative type liquid crystal is used and a good afterimage characteristic is obtained. An object is to provide an alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment agent.

  As a result of diligent research, the present inventor has found that a liquid crystal aligning agent containing a polyimide polymer having a specific structure is effective for achieving the above object, and has completed the present invention.

（式（１）、式（２）中、Ｘ_１及びＸ_２は_、それぞれ独立して、下記式（Ｘ１−１）及び（Ｘ１−２）で表される構造からなる群から選ばれる少なくとも１種である。Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、及びＲ_６は、それぞれ独立して、水素原子、又は炭素数１〜４のアルキル基である。Ｒ_５は、炭素数１〜４のアルキル基である。ｎは、１〜６の整数である。）

The present invention provides at least one polymer (A) selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (1) and the following formula (2) and an imidized polymer of the polyimide precursor (A). In a liquid crystal aligning agent characterized by comprising:

(Equation (1), wherein (2), _{X 1} and _{X 2} are each _{independently} at least 1 selected from the group consisting of structures represented by the following formula (X1-1) and (Xl-2) R ₁ , R _2, R ₃ , R ₄ , and R ₆ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₅ is an alkyl group having 1 to 4 carbon atoms. (N is an integer of 1 to 6.)

  According to the present invention, a liquid crystal aligning agent suitable for the photo-alignment process, which can suppress the bright spots found in the conventional photo-alignment process, has a high irradiation sensitivity, and has a good afterimage characteristic. Can be provided. By providing a liquid crystal alignment film obtained from such a liquid crystal aligning agent, a highly reliable liquid crystal display element without display defects can be provided.

<Specific polymer>
As described above, the liquid crystal aligning agent of the present invention is selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (1) and the following formula (2) and an imidized polymer of the polyimide precursor. At least one polymer (also referred to as a specific polymer (A) in the present invention). In the present invention, the structural unit represented by the formula (1) and the structural unit represented by the following formula (2) may be present in the same polyimide precursor, or represented by the formula (1). The structural unit represented by the following formula (2) may be present in a separate polyimide precursor.

In the above formulas (1) and (2), each definition of X ₁ , X ₂ , R _{1 and} R ₂ is as described above. Among these, X ₁ and X ₂ are preferably represented by the above formula (X1-2) from the viewpoint of high sensitivity and liquid crystal orientation. R ₁ and R ₂ are preferably a hydrogen atom, a methyl group, or an ethyl group from the viewpoint of ease of imidization by heating. R ₃ , R ₄ and R ₆ are preferably hydrogen atoms from the viewpoint of liquid crystal alignment. R ₅ is preferably a methyl group from the viewpoint of liquid crystal alignment. In addition, n is preferably an integer of 1 to 3, particularly 2, from the viewpoint of liquid crystal alignment.

<Manufacture of polyimide precursor-manufacture of polyamic acid>
The polyamic acid which is a polyimide precursor having the structural unit represented by the formula (1) and the structural unit represented by the formula (2) in the present invention is produced by the following method. In addition, in this invention, the polyimide precursor which has a structural unit represented by Formula (1), and the polyimide precursor which has a structural unit represented by Formula (2) are manufactured separately, respectively, You may manufacture by mixing.
Moreover, as a diamine to be subjected to polycondensation with tetracarboxylic acid or a dianhydride thereof, a diamine that gives a structural unit represented by formula (1) and a diamine that gives a structural unit represented by formula (2) are each 1 It is preferable to produce a polyimide precursor having a structural unit represented by the formula (1) and a structural unit represented by the formula (2) by using more than one type.

In this case, the tetracarboxylic acid or its dianhydride that gives X ₁ in the above formula (1) and the tetracarboxylic acid or its dianhydride that gives X ₂ in the above formula (2), the diamine that gives Y ₁ , and Y ₂ Is produced by a polycondensation reaction in the presence of a solvent at −20 to 150 ° C., preferably 0 to 50 ° C., for 30 minutes to 24 hours, preferably for 1 to 12 hours.
The reaction of diamine and tetracarboxylic acid is usually carried out in a solvent. The solvent used at that time is not particularly limited as long as the produced polyimide precursor is soluble. Although the specific example of the solvent used for reaction is given below, it is not limited to these examples.

  Examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-imidazolidinone. It is done. Further, when the solvent solubility of the polyimide precursor is high, it is represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formula [D-1] to formula [D-3]. Can be used.

（式［Ｄ−１］中、Ｄ^１は炭素数１〜３のアルキル基を示し、式［Ｄ−２］中、Ｄ^２は炭素数１〜３のアルキル基を示し、式［Ｄ−３］中、Ｄ^３は炭素数１〜４のアルキル基を示す）。
これら溶媒は単独で使用しても、混合して使用してもよい。更に、ポリイミド前駆体を溶解させない溶媒であっても、生成したポリイミド前駆体が析出しない範囲で、前記溶媒に混合して使用してもよい。また、溶媒中の水分は重合反応を阻害し、更には生成したポリイミド前駆体を加水分解させる原因となるので、溶媒は脱水乾燥させたものを用いることが好ましい。

(In the formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, and in the formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and the formula [D-3 ], D < ³ > shows a C1-C4 alkyl group.
These solvents may be used alone or in combination. Furthermore, even if it is a solvent which does not dissolve a polyimide precursor, you may mix and use it for the said solvent in the range which the produced | generated polyimide precursor does not precipitate. Further, since water in the solvent inhibits the polymerization reaction and further causes hydrolysis of the produced polyimide precursor, it is preferable to use a dehydrated and dried solvent.

  In order to obtain polyamic acid alkyl ester, a method of polycondensing a tetracarboxylic acid obtained by dialkyl esterifying a carboxylic acid group with a primary or secondary diamine compound, a tetracarboxylic acid obtained by dialkyl esterifying a carboxylic acid group A method of polycondensation of a dihalide and a primary or secondary diamine compound or a method of converting a carboxy group of a polyamic acid into an ester is used.

  When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the solution in which the diamine component is dispersed or dissolved in the solvent is stirred, and the tetracarboxylic acid component is added as it is or dispersed or dissolved in the solvent. Methods, conversely, a method of adding a diamine component to a solution in which a tetracarboxylic acid component is dispersed or dissolved in a solvent, a method of alternately adding a diamine component and a tetracarboxylic acid component, etc., and any of these methods May be used. In addition, when reacting using a plurality of diamine components or tetracarboxylic acid components, they may be reacted in a premixed state, individually or sequentially, or further individually reacted low molecular weight substances. May be mixed and reacted to form a polymer.

Although the polymerization temperature in that case can select arbitrary temperature of -20-150 degreeC, Preferably it is the range of -5-100 degreeC. The reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution will become too high and uniform stirring will occur. It becomes difficult. Therefore, Preferably it is 1-50 mass%, More preferably, it is 5-30 mass%. The initial reaction can be carried out at a high concentration, and then a solvent can be added.
In the polymerization reaction of the polyimide precursor, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2, particularly preferably 0.9 to 1.0. Similar to a normal polycondensation reaction, the molecular weight of the polyimide precursor produced increases as the molar ratio approaches 1.0.

The polyimide in the present invention is a polyimide obtained by cyclization of the polyimide precursor. To obtain the polyimide, a method of cyclizing the polyamic acid or polyamic acid alkyl ester to form a polyimide is used.
In the polyimide of the present invention, the cyclization rate (also referred to as imidization rate) of the amic acid group does not necessarily need to be 100%, and can be arbitrarily adjusted according to the application and purpose, preferably 50 to 80%. It is.

Examples of the method for imidizing the polyimide precursor include thermal imidization in which the polyimide precursor solution is heated as it is, or catalytic imidization in which a catalyst is added to the polyimide precursor solution. The temperature when the polyimide precursor is thermally imidized in the solution is 100 to 400 ° C., preferably 120 to 250 ° C., and it is preferable to carry out while removing water generated by the imidation reaction from the system. The reaction time is preferably 30 minutes to 4 hours.
The catalyst imidation of the polyimide precursor can be performed by adding a basic catalyst and an acid anhydride to the polyimide precursor solution and stirring at -20 to 250 ° C, preferably 0 to 180 ° C. The reaction time is preferably 30 minutes to 4 hours.
The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times of the amidic acid group, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol of the amido acid group. Is double. As basic catalysts there may be mentioned pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Of these, pyridine is preferable because it has a basicity suitable for advancing the reaction.

  Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Of these, use of acetic anhydride is preferred because purification after completion of the reaction is facilitated. The imidization rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

  When recovering the produced polyimide precursor or polyimide from the polyimide precursor or polyimide reaction solution, the reaction solution may be poured into a solvent and precipitated. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated in the solvent can be recovered by filtration, and then dried at normal temperature or under reduced pressure at room temperature or by heating. Moreover, when the polymer which carried out precipitation collection | recovery is redissolved in a solvent and the operation which carries out reprecipitation collection | recovery is repeated 2 to 10 times, the impurity in a polymer can be decreased. Examples of the solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more kinds of solvents selected from these because purification efficiency is further improved.

Polyamide acid alkyl ester is preferably used for the specific polymer (A) of the present invention. Preferred specific methods for producing the polyamic acid alkyl ester are shown in the following (1) to (3).
(1) Method of producing by polyamic acid esterification reaction Polyamic acid is produced from a diamine component and a tetracarboxylic acid component, and the carboxy group (COOH group) is subjected to a chemical reaction, that is, an esterification reaction. This is a method for producing an alkyl ester.
Specifically, in the esterification reaction, the polyamic acid and the esterifying agent are present in the presence of a solvent, preferably at -20 to 150 ° C, more preferably at 0 to 50 ° C, preferably 30 minutes to 24 hours, more preferably. Is allowed to react for 1 to 4 hours.

  The esterifying agent is preferably one that can be easily removed after the esterification reaction. N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl -3-p-tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents per 1 mol of the polyamic acid repeating unit. Especially, 2-4 molar equivalent is preferable.

Examples of the solvent used for the esterification reaction include a solvent used for the reaction of the diamine component and the tetracarboxylic acid component from the viewpoint of solubility of the polyamic acid in the solvent. Of these, N, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferable. You may use a solvent 1 type or in mixture of 2 or more types.
The concentration of the polyamic acid in the solvent in the esterification reaction is preferably 1 to 30% by mass from the viewpoint that precipitation of the polyamic acid hardly occurs. Especially, 5-20 mass% is preferable.

(2) Method of producing by reaction of diamine component and tetracarboxylic acid diester dichloride The reaction of diamine component and tetracarboxylic acid diester dichloride specifically includes a diamine component and tetracarboxylic acid diester dichloride, a base and a solvent. Is preferably -20 to 150 ° C, more preferably 0 to 50 ° C, and preferably 30 minutes to 24 hours, more preferably 1 to 4 hours.

  As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used. Of these, pyridine is preferable because the reaction proceeds gently. The amount of the base used is preferably an amount that can be easily removed after the reaction, and is preferably 2 to 4 moles relative to the tetracarboxylic acid diester dichloride. Especially, 2 to 3 times mole is more preferable.

  Examples of the solvent used in the reaction include a solvent used in the reaction of the diamine component and the tetracarboxylic acid component from the viewpoint of the solubility of the resulting polymer, that is, the polyamic acid alkyl ester, in the solvent. Of these, N, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferable. These solvents may be used alone or in combination of two or more.

  The concentration of the polyamic acid alkyl ester in the solvent in the reaction is preferably 1 to 30% by mass from the viewpoint that precipitation of the polyamic acid alkyl ester hardly occurs. Especially, 5-20 mass% is preferable. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, it is preferable that the solvent used for preparing the polyamic acid alkyl ester is dehydrated as much as possible. Furthermore, the reaction is preferably performed in a nitrogen atmosphere to prevent outside air from being mixed.

(3) Method of manufacturing by reaction of diamine component and tetracarboxylic acid diester This is a method of manufacturing by polycondensation reaction of diamine component and tetracarboxylic acid diester. Specifically, the diamine component and tetracarboxylic acid diester In the presence of a condensing agent, a base and a solvent, the reaction is preferably carried out at 0 to 150 ° C., more preferably at 0 to 100 ° C., preferably for 30 minutes to 24 hours, more preferably for 3 to 15 hours.

  Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazi Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like can be used. The amount of the condensing agent used is preferably 2 to 3 moles, more preferably 2 to 2.5 moles, with respect to the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base used is preferably an amount that can be easily removed after the polycondensation reaction, preferably 2 to 4 times mol, particularly preferably 2 to 3 times mol, of the diamine component.
Examples of the solvent used for the polycondensation reaction include a solvent used for the reaction of the diamine component and the tetracarboxylic acid component from the viewpoint of solubility of the polyamic acid alkyl ester, which is a polymer, in the solvent. In particular, N, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone is preferable. Two or more solvents may be mixed and used.
In the polycondensation reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The amount of the Lewis acid used is preferably 0.1 to 10-fold mol, more preferably 2.0 to 3.0-fold mol based on the diamine component.

When recovering the polyamic acid alkyl ester from the polyamic acid alkyl ester solution obtained by the methods (1) to (3) above, the reaction solution may be poured into a solvent and precipitated. Examples of the solvent used for precipitation include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene and the like. The polymer precipitated in the solvent is preferably washed with the solvent several times for the purpose of removing the additives and catalysts used above. After being collected by filtration, it can be dried at normal temperature or under reduced pressure at room temperature or by heating. Moreover, when the polymer which carried out precipitation collection is re-dissolved in a solvent and the operation which carries out reprecipitation collection is repeated 2-10 times, the impurity in a polymer can be decreased. Examples of the solvent at this time include a solvent in which the polymer is dissolved.
The polyamic acid alkyl ester of the present invention is preferably the method (1) or (2) among the methods (1) to (3).

<Liquid crystal aligning agent>
The liquid crystal alignment agent is a coating solution for forming a liquid crystal alignment film (also referred to as a resin film), and is a coating solution for forming a liquid crystal alignment film containing a specific polymer (A) and a solvent. Although content of the specific polymer (A) in a liquid crystal aligning agent can be suitably changed with the coating method of a liquid crystal aligning agent, and the film thickness of the target liquid crystal aligning film, it is 2-10 mass%. Is preferable, and 3 to 7% by mass is particularly preferable. On the other hand, the content of the solvent is preferably 70 to 99.9% by mass, and more preferably 90 to 98% by mass.

The solvent used for the liquid crystal aligning agent of the present invention is a solvent (also referred to as a good solvent) that dissolves the specific polymer (A), and an organic solvent is particularly preferable. Although the specific example of a good solvent is given to the following, it is not limited to these examples.
For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone , Cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and the like. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferably used.

Furthermore, when the solubility of the specific polymer (A) in the solvent is high, it is preferable to use the solvent represented by the formula [D-1] to the formula [D-3].
The good solvent in the liquid crystal aligning agent is preferably 20 to 99% by mass of the whole solvent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.
Unless the effect of this invention is impaired, a liquid crystal aligning agent can contain the solvent (it is also called a poor solvent) which improves the coating property of a liquid crystal aligning film at the time of apply | coating a liquid crystal aligning agent, and surface smoothness. These poor solvents are preferably 1 to 80% by mass of the entire solvent contained in the liquid crystal aligning agent. Especially, 10-80 mass% is preferable. More preferred is 20 to 70% by mass.

  Although the specific example of a poor solvent is given to the following, it is not limited to these examples. For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2- Etanji 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentane Diol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2 Heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1- (Butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate Tar, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol Monoethyl ether, milk Methyl, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3-methoxypropion Ethyl acid, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, lactic acid Examples thereof include isoamyl esters and solvents represented by the formula [D-1] to the formula [D-3].

  Among these, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether is preferably used.

  The liquid crystal aligning agent of the present invention has at least one substituent selected from the group consisting of a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a hydroxy group, a hydroxyalkyl group and a lower alkoxyalkyl group. It is preferable to introduce a crosslinkable compound having a crosslinkable compound or a crosslinkable compound having a polymerizable unsaturated bond. It is necessary to have two or more of these substituents and polymerizable unsaturated bonds in the crosslinkable compound.

  Examples of the crosslinkable compound having an epoxy group or an isocyanate group include bisphenolacetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, tetraglycidylaminodiphenylene, tetraglycidyl-m-xylenediamine, tetra Glycidyl-1,3-bis (aminoethyl) cyclohexane, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetodiglycidyl ether, 1,3-bis (1- (2,3-epoxypropoxy)- 1-trifluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-epoxypropoxy) octafluorobiphenyl, Liglycidyl-p-aminophenol, tetraglycidylmetaxylenediamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4- (2,3-epoxy) Propoxy) phenyl) ethyl) phenyl) propane, 1,3-bis (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1- (4- (1- (4- (2,3 -Epoxypropoxy) phenyl) -1-methylethyl) phenyl) ethyl) phenoxy) -2-propanol and the like.

具体的には、国際公開公報ＷＯ2011／132751号（2011．10.27公開）の５８〜５９頁に掲載される式［４ａ］〜式［４ｋ］で示される架橋性化合物が挙げられる。The crosslinkable compound having an oxetane group is a compound having at least two oxetane groups represented by the following formula [4A].

Specific examples include crosslinkable compounds represented by the formulas [4a] to [4k] published on pages 58 to 59 of International Publication No. WO2011 / 132751 (published on October 27, 2011).

具体的には、国際公開公報ＷＯ2012／014898号（2012.2．2公開）の７６〜８２頁に掲載される式［５−１］〜式［５−４２］で示される架橋性化合物が挙げられる。The crosslinkable compound having a cyclocarbonate group is a crosslinkable compound having at least two cyclocarbonate groups represented by the following formula [5A].

Specific examples include crosslinkable compounds represented by the formulas [5-1] to [5-42] published on pages 76 to 82 of International Publication No. WO2012 / 014898 (published on 2.2.2.2012).

  Examples of the crosslinkable compound having at least one substituent selected from the group consisting of a hydroxy group and an alkoxy group include an amino resin having a hydroxy group or an alkoxy group, such as a melamine resin, a urea resin, a guanamine resin, and a glycoluril. -Formaldehyde resin, succinylamide-formaldehyde resin, ethylene urea-formaldehyde resin, etc. are mentioned. Specifically, a melamine derivative, a benzoguanamine derivative, or glycoluril in which a hydrogen atom of an amino group is substituted with a methylol group, an alkoxymethyl group, or both can be used. The melamine derivative or benzoguanamine derivative can exist as a dimer or a trimer. These preferably have an average of 3 to 6 methylol groups or alkoxymethyl groups per triazine ring.

  Examples of the melamine derivative or benzoguanamine derivative include MX-750 in which an average of 3.7 methoxymethyl groups are substituted per one triazine ring, and an average of 5.8 methoxymethyl groups per one triazine ring. Individually substituted MW-30 (manufactured by Sanwa Chemical Co., Ltd.) and Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712 and other methoxymethylated melamines, Cymel 235, 236, Methoxymethylated butoxymethylated melamine such as 238, 212, 253, and 254, butoxymethylated melamine such as Cymel 506 and 508, carboxy group-containing methoxymethylated isobutoxymethylated melamine such as Cymel 1141, Cymel 1123 and the like Methoxymethylated ethoxymethyl Benzoguanamine, methoxymethylated butoxymethylated benzoguanamine such as Cymel 1123-10, butoxymethylated benzoguanamine such as Cymel 1128, carboxymethyl-containing methoxymethylated ethoxymethylated benzoguanamine such as Cymel 1125-80 Manufactured). Examples of glycoluril include butoxymethylated glycoluril such as Cymel 1170, methylolated glycoluril such as Cymel 1172, methoxymethylolated glycoluril such as Powderlink 1174, and the like.

Examples of the benzene or phenolic compound having a hydroxy group or an alkoxy group include 1,3,5-tris (methoxymethyl) benzene, 1,2,4-tris (isopropoxymethyl) benzene, 1,4-bis ( sec-butoxymethyl) benzene or 2,6-dihydroxymethyl-p-tert-butylphenol.
More specifically, the crosslinkable compounds of the formulas [6-1] to [6-48], which are listed on pages 62 to 66 of International Publication No. WO2011 / 132751 (published on October 27, 2011).

  Examples of the crosslinkable compound having a polymerizable unsaturated bond include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and tri (meth) acryloyloxyethoxytrimethylol. Crosslinkable compounds having three polymerizable unsaturated groups in the molecule such as propane and glycerin polyglycidyl ether poly (meth) acrylate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) ) Acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (me ) Acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide bisphenol A type di (meth) acrylate, propylene oxide bisphenol type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) ) Acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl ester phthalate di (meth) acrylate, neopentyl glycol dihydroxypivalate Crosslinkable compounds having two polymerizable unsaturated groups in the molecule such as (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypro (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, 3-chloro-2-hydroxypropyl Crosslinkable compounds having one polymerizable unsaturated group in the molecule, such as (meth) acrylate, glycerin mono (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate ester, N-methylol (meth) acrylamide, etc. Is mentioned.

（式［７Ａ］中、Ｅ_１はシクロヘキサン環、ビシクロヘキサン環、ベンゼン環、ビフェニル環、ターフェニル環、ナフタレン環、フルオレン環、アントラセン環及びフェナントレン環からからなる群から選ばれる基を示し、Ｅ_２は下記式［７ａ］及び式［７ｂ］から選ばれる基を示し、ｎは１〜４の整数を示す。）

上記は架橋性化合物の一例であり、これらに限定されるものではない。また、本発明の液晶配向剤に用いる架橋性化合物は、１種類でも、２種類以上組み合わせてもよい。Furthermore, a compound represented by the following formula [7A] can also be used.

(In the formula [7A], E ₁ represents a group selected from the group consisting of a cyclohexane ring, a bicyclohexane ring, a benzene ring, a biphenyl ring, a terphenyl ring, a naphthalene ring, a fluorene ring, an anthracene ring and a phenanthrene ring; ₂ represents a group selected from the following formula [7a] and formula [7b], and n represents an integer of 1 to 4.

The above is an example of a crosslinkable compound, but is not limited thereto. Moreover, the crosslinkable compound used for the liquid crystal aligning agent of this invention may be 1 type, or may combine 2 or more types.

  As for content of a crosslinkable compound in the liquid crystal aligning agent of this invention, 0.1-150 mass parts is preferable with respect to 100 mass parts of all the polymer components. Especially, in order for a crosslinking reaction to advance and to express the target effect, 0.1-100 mass parts is preferable with respect to 100 mass parts of all the polymer components. More preferred is 1 to 50 parts by mass.

As long as the effects of the present invention are not impaired, the liquid crystal aligning agent of the present invention can use a compound that improves the uniformity of the film thickness and surface smoothness of the liquid crystal aligning film when the liquid crystal aligning agent is applied.
Examples of the compound that improves the film thickness uniformity and surface smoothness of the liquid crystal alignment film include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.
More specifically, for example, F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFuck F171, F173, R-30 (above, manufactured by Dainippon Ink, Inc.), Florard FC430, FC431 (or more) Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.) and the like.
The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

  Furthermore, the liquid crystal aligning agent is published on pages 69 to 73 of International Publication No. WO2011 / 132751 (published on 10.27.2011) as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge release of the device. A nitrogen-containing heterocyclic amine compound represented by the formulas [M1] to [M156] can also be added. The amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add the amine compound after forming a solution having a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. The solvent is not particularly limited as long as the specific polymer (A) is dissolved.

  The liquid crystal aligning agent of the present invention includes, in addition to the above-mentioned poor solvent, crosslinkable compound, resin film or compound that improves the film thickness uniformity and surface smoothness of the liquid crystal aligning film, and a compound that promotes charge removal. As long as the effects of the invention are not impaired, a dielectric or conductive material for changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal alignment film may be added.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal alignment film is a film obtained by applying the liquid crystal aligning agent to a substrate, drying, and baking. The substrate on which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with a glass substrate or a silicon nitride substrate. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is used from the viewpoint of simplification of the process. In the reflective liquid crystal display element, an opaque object such as a silicon wafer can be used as long as only one substrate is used, and a material that reflects light such as aluminum can be used for the electrode in this case.

A method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method performed by screen printing, offset printing, flexographic printing, an inkjet method, or the like is common. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method, and a spray method, and these may be used depending on the purpose.
After the liquid crystal aligning agent is applied on the substrate, the solvent can be evaporated by a heating means such as a hot plate, a thermal circulation oven, an IR (infrared) oven, or the like to form a liquid crystal alignment film. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, in order to sufficiently remove the contained solvent, it is dried at 50 to 120 ° C., preferably 60 to 100 ° C. for 1 to 10 minutes, preferably 1 to 5 minutes, and then 150 to 300 ° C., Preferably, the conditions include baking at 180 to 250 ° C. for 5 to 120 minutes, preferably 10 to 60 minutes. Since the reliability of a liquid crystal display element may fall when the thickness of the liquid crystal aligning film after baking is too thin, 5-300 nm is preferable and 10-200 nm is more preferable.

  The method for aligning the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention may be a rubbing method, but an optical alignment method is preferred. As a preferable example of the photo-alignment treatment method, the surface of the liquid crystal alignment film is irradiated with radiation deflected in a certain direction, and in some cases, preferably, a heat treatment is performed at a temperature of 150 to 250 ° C. And a method of imparting (also referred to as liquid crystal alignment ability). As the radiation, ultraviolet rays or visible rays having a wavelength of 100 to 800 nm can be used. Among these, ultraviolet rays having a wavelength of preferably 100 to 400 nm, more preferably 200 to 400 nm are preferable.

Moreover, in order to improve liquid crystal orientation, you may irradiate a radiation, heating the board | substrate with which the liquid crystal aligning film was coated at 50-250 degreeC.
The radiation dose is preferably 1 to 10,000 mJ / cm ² . Of these, 100 to 5,000 mJ / cm ² is preferable. The liquid crystal alignment film thus prepared can stably align liquid crystal molecules in a certain direction.
Further, the liquid crystal alignment film irradiated with polarized radiation can be subjected to contact treatment using water or a solvent by the above method.

  The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves a decomposition product generated from the liquid crystal alignment film by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Examples include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like. Of these, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable from the viewpoint of versatility and solvent safety. More preferred is water, 1-methoxy-2-propanol or ethyl lactate. The solvent may be used alone or in combination of two or more.

  Examples of the contact treatment include immersion treatment and spray treatment (also referred to as spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour from the viewpoint of efficiently dissolving the decomposition products generated from the liquid crystal alignment film by radiation. Especially, it is preferable to immerse for 1 to 30 minutes. Moreover, although the solvent at the time of the said contact process may be heated even at normal temperature, Preferably it is 10-80 degreeC. Especially, 20-50 degreeC is preferable. In addition, from the viewpoint of the solubility of the decomposition product, ultrasonic treatment or the like may be performed as necessary.

  After the contact treatment, it is preferable to perform rinsing (also referred to as rinsing) with a low-boiling solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, and baking of the liquid crystal alignment film. At that time, either one of rinsing and firing, or both may be performed. The firing temperature is preferably 150 to 300 ° C. Especially, 180-250 degreeC is preferable. More preferably, it is 200-230 degreeC. The firing time is preferably 10 seconds to 30 minutes. Among these, 1 to 10 minutes is preferable.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film of a horizontal electric field type liquid crystal display element such as an IPS mode or an FFS mode, and is particularly useful as a liquid crystal alignment film of an FFS mode liquid crystal display element. The liquid crystal display element is obtained using a liquid crystal cell by preparing a liquid crystal cell by a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention.
As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Note that an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting the image display may be used.

Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be ITO electrodes, for example, and are patterned so as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a SiO ₂ —TiO ₂ film formed by a sol-gel method.

  Next, a liquid crystal alignment film is formed on each substrate, the other substrate is overlapped with one substrate so that the liquid crystal alignment film faces each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealant, and it is preferable to spray a spacer for controlling the substrate gap on the in-plane portion where no sealant is provided. A part of the sealant is provided with an opening that can be filled with liquid crystal from the outside. Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing agent through the opening provided in the sealing agent, and then the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. As the liquid crystal material, either a positive liquid crystal material or a negative liquid crystal material may be used, but a negative liquid crystal material is preferable. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer.

  As described above, by using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning film that suppresses afterimages due to AC driving and has both adhesiveness with the sealing agent and the base substrate. In particular, it is useful for a liquid crystal alignment film for photo-alignment treatment obtained by irradiating polarized radiation.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The abbreviations of the compounds used below and the measuring methods of the respective properties are as follows.
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolv DA-1: 1,2-bis (4-aminophenoxy) ethane DA-2: 4- (2- (methylamino) ethyl) aniline DA-3: p- Phenylenediamine DA-4: 4- (2-aminoethyl) aniline DA-5: See formula (DA-5) below

[viscosity]
Viscosity of polyamic acid ester, polyamic acid solution, etc. is based on E type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), sample volume 1.1 mL, cone rotor TE-1 (1 ° 34 ′, R24), temperature Measured at 25 ° C.

[Molecular weight]
The molecular weight of polyamic acid ester and the like was measured by a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) were calculated as polyethylene glycol and polyethylene oxide equivalent values.
GPC apparatus: manufactured by Shodex (GPC-101), column: manufactured by Shodex (KD803, series of KD805), column temperature: 50 ° C., eluent: N, N-dimethylformamide (as an additive, lithium bromide-water) Japanese (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L), flow rate: 1.0 ml / min. Standard samples for use: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (peak top molecular weight (Mp) manufactured by Polymer Laboratories) ) About 12,000, 4,000, 1,000). In order to avoid the overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and three types of 150,000, 30,000, and 4,000. Two samples of the mixed sample were measured separately.

[Anisotropy of alignment film]
Measurement was performed using a liquid crystal alignment film evaluation system “Ray Scan Lab H” (LYS-LH30S-1A) manufactured by Moritex Corporation. A polyimide film with a thickness of 100 nm was irradiated with linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 10: 1 or more through a polarizing plate, and the magnitude of anisotropy with respect to the alignment direction of the obtained alignment film was measured.

[Production of liquid crystal cell]
A liquid crystal cell having a configuration of a fringe field switching (FFS) mode liquid crystal display element is manufactured.
First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 50 mm and a thickness of 0.7 mm. On the substrate, an ITO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. A comb-like pixel electrode formed by patterning an ITO film is arranged as a third layer on the second SiN film to form two pixels, a first pixel and a second pixel. doing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

  The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of dog-shaped electrode elements having a bent central portion. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is configured by arranging a plurality of bent-shaped electrode elements having a bent central portion, the shape of each pixel is not a rectangular shape, and the central portion is similar to the electrode element. It has a shape similar to the bold “ku” character bent at Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

  When the first region and the second region of each pixel are compared, the formation directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode element of the electrode is formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode are mutually in the substrate plane. It is comprised so that it may become a reverse direction.

  Next, after the liquid crystal aligning agent is filtered through a 1.0 μm filter, spin coating is applied to the prepared substrate with electrodes and a glass substrate having a 4 μm high columnar spacer on which an ITO film is formed on the back surface. Was applied. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The coated film surface was irradiated with linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 10: 1 or more via a polarizing plate. This substrate is immersed in at least one solvent selected from water and an organic solvent for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 to 300 ° C. for 5 minutes, with a liquid crystal alignment film A substrate was obtained. The two substrates are combined as a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is added. An empty cell was produced by curing. Liquid crystal MLC-7026-100 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

[Afterimage evaluation by long-term AC drive]
A liquid crystal cell having the same structure as the liquid crystal cell used for the above-described afterimage evaluation was prepared.
Using this liquid crystal cell, an AC voltage of ± 5 V was applied for 120 hours at a frequency of 60 Hz in a constant temperature environment of 60 ° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.
After leaving, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the backlight is turned on with no voltage applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, for the second pixel, the second area was compared with the first area, and a similar angle Δ was calculated. The average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell, and the liquid crystal orientation was evaluated based on the magnitude of the value. That is, if the value of the angle Δ is small, the liquid crystal alignment is good.

[Evaluation of bright spot of liquid crystal cell (contrast)]
The bright spot of the liquid crystal cell produced in the same manner as described above (production of liquid crystal cell) was evaluated.
This was done by observing the liquid crystal cell with a polarizing microscope (ECLIPSE E600WPOL) (Nikon Corp.). Specifically, the number of bright spots confirmed by observing the liquid crystal cell with a polarizing microscope in which the liquid crystal cell is installed in crossed Nicols and the magnification is 5 times is counted, and the number of bright spots is less than 10. “Good” and more than “bad”.

<Synthesis Example 1>
In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.01 g (4.20 mmol) DA-1, 0.421 g (2.80 mmol) DA-2, 0.76 g DA-3 ( 7.00 mmol) was weighed, 33.60 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 2.95 g (13.16 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further adjusted to 12% by mass. Then, 3.73 g of NMP was added. Thereafter, the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (A). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 316 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 13530 and Mw = 29850.

<Synthesis Example 2>
In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 0.95 g (3.90 mmol) of DA-1, 0.98 g (6.5 mmol) of DA-2, and 0.35 g of DA-4 ( 2.60 mmol) was weighed, 33.15 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 2.74 g (12.22 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further increased to 12% by mass. Then, 3.73 g of NMP was added. Thereafter, the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (B). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 483 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 14260 and Mw = 30050.

<Synthesis Example 3>
Weigh out 1.47 g (6.00 mmol) DA-1 and 0.90 g (6.00 mmol) DA-1 in a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and add 31.96 g NMP. The mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 2.60 g (11.58 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further adjusted to 12% by mass. Then, 3.55 g of NMP was added. Thereafter, the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (C). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 423 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 104010 and Mw = 29540.

<Synthesis Example 4>
In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.59 g (6.50 mmol) DA-1 and 0.70 g (6.50 mmol) DA-3 were weighed and 33.01 g NMP was added. The mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 2.78 g (12.42 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further increased to 12% by mass. Then, 3.66 g of NMP was added. Then, it stirred at room temperature for 24 hours and obtained the polyamic acid solution (D). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 360 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 13810 and Mw = 28400.

<Synthesis Example 5>
In a 50 mL four-necked flask with a stirrer and a nitrogen inlet tube, 1.0-1 g (4.20 mmol) of DA-1, 0.76 g (7.00 mmol) of DA-3, and 0.38 g of DA-4 ( 2.80 mmol) was weighed, 34.38 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 3.04 g (13.58 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further increased to 12% by mass. Then, 3.82 g of NMP was added. Thereafter, the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (E). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 428 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 14800 and Mw = 29960.

<Synthesis Example 6>
To a 50 mL four-necked flask with a stirrer and a nitrogen inlet tube, weigh out 1.13 g (7.50 mmol) DA-2 and 0.81 g (7.50 mmol) DA-3, and add 33.87 g NMP. The mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 3.39 g (14.85 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride was added, and the solid content concentration was further increased to 12% by mass. 3.76 g of NMP was added. Then, it stirred at room temperature for 24 hours and obtained the polyamic acid solution (F). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 280 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 12250 and Mw = 26550.

<Synthesis Example 7>
To a 50 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, weigh out 3.36 g (15.00 mmol) of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and add NMP. 3.73 g was added and dissolved by stirring while feeding nitrogen. While stirring the acid dianhydride solution, 1.13 g (12.68 mmol) of DA-3 and 0.81 g (1.50 mmol) of DA-5 were added, and the solid content concentration was further 10% by mass. 7.46 g of NMP was added. Then, it stirred at room temperature for 24 hours and obtained the polyamic acid solution (G). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 460 mPa · s. Moreover, the molecular weight of this polyamic acid was Mn = 152020 and Mw = 33320.

<Example 1>
Weigh 15.00 g of 12% polyamic acid solution (A) in a 100 ml Erlenmeyer flask, add 9.00 g of NMP and 6.00 g of BCS, and mix at 25 ° C. for 8 hours to obtain a liquid crystal aligning agent (1). It was. This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.
<Example 2>
Except having used 15.00 g of 12 mass% polyamic acid solutions (B), it implemented similarly to Example 1 and obtained the liquid crystal aligning agent (2). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 3>
A liquid crystal aligning agent (3) was obtained in the same manner as in Example 1 except that 15.00 g of a 12% by mass polyamic acid solution (C) was used. This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.
<Comparative Example 1>
Except having used 15.00 g of 12 mass% polyamic acid solutions (D), it implemented similarly to Example 1 and obtained the liquid crystal aligning agent (4). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Comparative example 2>
A liquid crystal aligning agent (5) was obtained in the same manner as in Example 1 except that 15.00 g of a 12% by mass polyamic acid solution (E) was used. This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.
<Comparative Example 3>
Except having used 15.00 g of 12 mass% polyamic acid solutions (F), it implemented similarly to Example 1 and obtained the liquid crystal aligning agent (6). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.
<Comparative Example 4>
A liquid crystal aligning agent (7) was obtained in the same manner as in Example 1 except that 15.00 g of a 12% by mass polyamic acid solution (G) was used. This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

(Example 5)
The liquid crystal aligning agent (1) was filtered through a 1.0 μm filter and then spin-coated on a 30 mm × 40 mm ITO substrate. After drying on an 80 ° C. hot plate for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a thickness of 100 nm. This coating film surface was irradiated with a linearly polarized ultraviolet ray having a wavelength of 254 nm with an extinction ratio of 26: 1 through a polarizing plate to obtain a liquid crystal alignment film.
The height of anisotropy with respect to the alignment direction of the obtained liquid crystal alignment film was measured. Anisotropy value of the amount of irradiation at 200 mJ / cm ² of said UV is 3.39, anisotropy value at 300 mJ / cm ² is 4.10, anisotropic at 400 mJ / cm ² The sex value was 3.26. The irradiation amount of the ultraviolet ray having the highest anisotropy was 300 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Example 6)
Except having used the said liquid crystal aligning agent (2), it implemented similarly to Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. Anisotropy value at the amount of irradiation is 50 mJ / cm ² of said UV is 0.05, anisotropy value at 100 mJ / cm ² is 0.61, anisotropic at 200 mJ / cm ² The sex value was 0.06. The irradiation amount of the ultraviolet ray having the greatest anisotropy was 100 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Example 7)
Except having used the said liquid crystal aligning agent (3), it implemented like Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. 0.10 anisotropic value of the irradiation amount of 50 mJ / cm ² of the ultraviolet, anisotropy value at 100 mJ / cm ² is 0.92, anisotropic at 200 mJ / cm ² The sex value was 0.15. The irradiation amount of the ultraviolet ray having the greatest anisotropy was 100 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Comparative Example 5)
Except having used the said liquid crystal aligning agent (4), it implemented like Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. The anisotropy value of the irradiation amount of the ultraviolet rays at 100 mJ / cm ² is 3.02, the anisotropy value at 200 mJ / cm ² is 5.37, anisotropic at 300 mJ / cm ² The sex value was 3.40. The irradiation amount of the ultraviolet ray having the greatest anisotropy was 200 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Comparative Example 6)
Except having used the said liquid crystal aligning agent (5), it implemented like Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. Anisotropy value of the irradiation amount of 200 mJ / cm ² of said UV is 4.28, anisotropy value at 300 mJ / cm ² is 4.57, anisotropic at 400 mJ / cm ² The sex value was 3.03. The irradiation amount of the ultraviolet ray having the largest anisotropy was 300 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Comparative Example 7)
Except having used the said liquid crystal aligning agent (6), it implemented similarly to Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. 0.54 anisotropic value of the irradiation amount of 300 mJ / cm ² of the ultraviolet, anisotropy value at 400 mJ / cm ² is 0.65, anisotropic at 500 mJ / cm ² The sex value was 0.60. The irradiation amount of the ultraviolet ray having the greatest anisotropy was 400 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

(Comparative Example 8)
Except having used the said liquid crystal aligning agent (7), it implemented like Example 5 and obtained the liquid crystal aligning film. The anisotropic magnitude | size with respect to the orientation direction of the obtained liquid crystal aligning film was measured. 1.61 anisotropic value of the irradiation amount of 400 mJ / cm ² of the ultraviolet, anisotropy value at 600 mJ / cm ² is 1.71, anisotropic at 800 mJ / cm ² The sex value was 1.59. The irradiation amount of the ultraviolet ray having the greatest anisotropy was 600 mJ / cm ² , and was the optimum irradiation condition in the photo-alignment treatment.

The results of measuring the magnitude of anisotropy with respect to the alignment direction of the liquid crystal alignment films obtained in Examples 5 to 7 and Comparative Examples 5 to 8 are summarized in Table 1.

(Example 8)
After the liquid crystal aligning agent (1) is filtered through a 1.0 μm filter, spin is applied to the prepared substrate with electrodes and a glass substrate having a columnar spacer with a height of 4 μm on which an ITO film is formed on the back surface. It applied by coat application. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 0.3 J / cm ² of linearly polarized ultraviolet light having an extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. Set the two substrates as a set, print the sealant on the substrate, and bond the other substrate so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is cured. An empty cell was produced. Liquid crystal MLC-7026-100 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell. Then, after heating the obtained liquid crystal cell at 110 degreeC for 1 hour, it was left overnight and the afterimage evaluation by long-term alternating current drive was implemented. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.04 degrees. Further, as a result of observing the bright spots in the cell, the number of bright spots was less than 10, which was favorable.

Example 9
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (2) was used. This coating surface was irradiated with 0.1 J / cm ² of linearly polarized UV light having a extinction ratio of 26: 1 at a wavelength of 254 nm through a polarizing plate, and then heated on a hot plate at 230 ° C. for 14 minutes to obtain liquid crystal alignment. A substrate with a film was obtained. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.10 degrees. Further, as a result of observing the bright spots in the cell, the number of bright spots was less than 10, which was favorable.

(Example 10)
After irradiating polarized ultraviolet rays, an FFS drive liquid crystal cell was produced in the same manner as in Example 9 except that it was immersed in 2-propanol for 3 minutes and then immersed in pure water for 1 minute. This FFS drive liquid crystal cell was subjected to afterimage evaluation by long-term AC drive. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.08 degrees. Further, as a result of observing the bright spots in the cell, the number of bright spots was less than 10, which was favorable.

(Example 11)
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (3) was used. This coating surface was irradiated with 0.1 J / cm ² of linearly polarized UV light having a extinction ratio of 26: 1 at a wavelength of 254 nm through a polarizing plate, and then immersed in 2-propanol for 3 minutes. Immerse for a minute. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.08 degrees. Further, as a result of observing the bright spots in the cell, the number of bright spots was less than 10, which was favorable.

(Comparative Example 9)
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (4) was used. The surface of the coating film was irradiated with 0.2 J / cm ² of linearly polarized UV light having an extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.15 degrees. Further, as a result of observation of the bright spots in the cell, the number of bright spots was 10 or more, which was poor.

(Comparative Example 10)
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (5) was used. The surface of the coating film was irradiated with 0.3 J / cm ² of linearly polarized ultraviolet light having an extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.20 degrees. Further, as a result of observation of the bright spots in the cell, the number of bright spots was 10 or more, which was poor.

(Comparative Example 11)
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (6) was used. This coating surface was irradiated with 0.4 J / cm ^{2 of} 254 nm linearly polarized UV light having an extinction ratio of 26: 1 via a polarizing plate. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.20 degrees. Further, as a result of observation of the bright spots in the cell, the number of bright spots was 10 or more, which was poor.

(Comparative Example 12)
A coating film having a thickness of 100 nm was formed in the same manner as in Example 8 except that the liquid crystal aligning agent (7) was used. The surface of the coating film was irradiated with 0.6 J / cm ² of linearly polarized ultraviolet light having an extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. Then, it heated for 14 minutes on a 230 degreeC hotplate, and obtained the board | substrate with a liquid crystal aligning film. An FFS drive liquid crystal cell was produced by the same method as in Example 8 except that this substrate with a liquid crystal alignment film was used, and afterimage evaluation by long-term alternating current drive was performed on the obtained cell. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.24 degrees. Further, as a result of observation of the bright spots in the cell, the number of bright spots was 10 or more, which was poor.

The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has few bright spots that cause a decrease in contrast, and can reduce afterimages caused by alternating current driving in liquid crystal display elements of the IPS driving method and the FFS driving method. In addition, an IPS driving type or FFS driving type liquid crystal display element having excellent afterimage characteristics can be obtained.
The liquid crystal display element having the liquid crystal alignment film of the present invention has excellent reliability, and can be widely used for liquid crystal televisions, small and medium-sized car navigation systems, smartphones, and the like that require a large screen, high definition, and high display quality. Can do.

  The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2014-219597 filed on October 28, 2014 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (11)

At least one selected from the group consisting of a polyimide precursor having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2) and an imidized polymer of the polyimide precursor. The liquid crystal aligning agent characterized by including the polymer (A).

(Equation (1), wherein (2), _{X 1} and _{X 2} are each _{independently} at least 1 selected from the group consisting of structures represented by the following formula (X1-1) and (Xl-2) R ₁ , R _2, R ₃ , R ₄ , and R ₆ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₅ is an alkyl group having 1 to 4 carbon atoms. (N is an integer of 1 to 6.)

  The content ratio of the structural unit represented by the formula (1) is 10 to 50 mol% with respect to 1 mol of all the structural units of the polymer (A), and is represented by the formula (2). The liquid crystal aligning agent of Claim 1 whose content rate of a structural unit is 20-90 mol% with respect to 1 mol of all the structural units of the said polymer (A).   The structural unit represented by the formula (1) and the structural unit represented by the following formula (2) may be present in the same polyimide precursor, and the structural unit represented by the formula (1) The liquid crystal aligning agent of Claim 1 or 2 with which the structural unit represented by following formula (2) and a separate polyimide precursor may exist. In the above formula (1) and (2), _{X 1} and _{X 2,} the liquid crystal alignment agent according to claim 1 wherein a formula (Xl-2). In Formula (1) and Formula (2), R ₁ and R ₂ are alkyl groups having 1 to 3 carbon atoms, R ₃ , R ₄ , R ₅ and R ₆ are hydrogen atoms, and n is 1 to 1 The liquid crystal aligning agent according to any one of claims 1 to 4, which is an integer of 3.   The liquid crystal aligning agent in any one of Claims 1-5 in which a polymer (A) contains 2-10 mass%.   The liquid crystal aligning agent according to claim 1, which is used for photo-alignment.   The manufacturing method of the liquid crystal aligning film which irradiates the polarized ultraviolet-ray to the film | membrane obtained by apply | coating and baking the liquid crystal aligning agent in any one of Claims 1-7.   The liquid crystal alignment film according to claim 7, wherein the polarized ultraviolet light has a wavelength of 100 to 800 nm.   The liquid crystal display element which has a liquid crystal aligning film of Claim 8 or 9.   The liquid crystal display element according to claim 10, wherein the liquid crystal is a negative liquid crystal material.