TW201727341A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

The present invention provides: a liquid crystal alignment agent that makes it possible to obtain a liquid crystal alignment film that has excellent rubbing resistance, fast reduction of accumulated charge and a high alignment regulating force; a liquid crystal display element, particularly of the transverse electric field type, that has excellent display properties; and a novel diamine that constitutes the raw material of the liquid crystal alignment agent. The liquid crystal alignment agent contains a polymer that has a structure represented by formula (1) in the main chain. (R1 is hydrogen or a monovalent organic group, Ar is a phenyl group or naphthalene group that can have a substituent group, and * represents a site that bonds with another group).

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

The present invention relates to a novel diamine compound for use as a raw material for a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal display element, and a polymer contained in a liquid crystal alignment agent used in a liquid crystal display device.

Liquid crystal display elements are widely used in display units of smart phones, notebook computers, mobile phones, televisions, and the like. The liquid crystal display element includes, for example, a liquid crystal layer sandwiched between the element substrate and the filter substrate, and an electric field applied to the pixel electrode of the liquid crystal layer and the common electrode, and an alignment film for controlling the alignment of the liquid crystal molecules of the liquid crystal layer, and switching A thin film transistor (TFT) or the like for supplying an electrical signal of a pixel electrode. The driving method of the liquid crystal molecules is known as a vertical electric field method such as a TN method or a VA method, or a horizontal electric field method such as an IPS method or an FFS method. A transverse electric field method in which an electric field is applied to a side of a substrate only in a direction parallel to the substrate is known to have a longitudinal electric field method in which a voltage is applied to an electrode formed on the upper and lower substrates to drive the liquid crystal. A liquid crystal display element having a wide viewing angle characteristic and high quality display property.

The liquid crystal cell of the transverse electric field mode has an excellent viewing angle However, since the electrode portion formed in the substrate is small, the voltage holding ratio is low and the liquid crystal cannot obtain a sufficient voltage, so the display contrast is lowered. Further, since the liquid crystal alignment has a small stability, the liquid crystal cannot be returned to the initial state when the liquid crystal is driven for a long period of time, and the reason for the reduction of contrast and afterimage is reduced. Therefore, the stability of the liquid crystal alignment is important. Further, since static electricity is easily accumulated in the liquid crystal cell, the positive and negative asymmetric voltages generated by the driving also cause the electric charge to accumulate in the liquid crystal cell, and the accumulated electric charge causes confusion and residual images of the liquid crystal alignment, thereby affecting the display property. Reduce the display quality of the liquid crystal element. Further, since the backlight is irradiated to the liquid crystal cell immediately after driving, electric charge is accumulated. Therefore, even if the afterimage is generated for a short period of time, there is a problem that the size of flicker (flicker) is changed during driving.

Further, in the manufacturing process of a general liquid crystal display element, the liquid crystal alignment film is formed by printing a liquid crystal alignment agent, drying, baking, and rubbing treatment. In the horizontal electric field type liquid crystal cell, since the substrate has an electrode structure on only one side of the substrate, the substrate has large irregularities, and an insulator such as tantalum nitride is formed on the surface of the substrate. Therefore, in comparison with the conventional alignment agent, it is required to have better printability. Liquid crystal alignment agent. Moreover, in order to improve the liquid crystal alignment stability, a stronger rubbing treatment than the previous liquid crystal cell is performed. Therefore, it is easy to peel off and rub the shavings due to the rubbing treatment, so that the peeling and the scratches may degrade the display quality.

A liquid crystal alignment agent which is excellent in voltage retention and which is capable of reducing charge accumulation when the liquid crystal element is driven by such a horizontal electric field is, for example, a liquid crystal alignment agent containing a specific diamine and an aliphatic tetracarboxylic acid derivative disclosed in Patent Document 1. Moreover, it has excellent liquid crystal alignment, abrasion resistance and light transmission. A liquid crystal alignment film containing a specific diamine and an aromatic tetracarboxylic acid derivative disclosed in Patent Document 2, which is a liquid crystal alignment film which is effective in reducing the afterimage in a higher temperature range. A liquid crystal alignment agent having excellent liquid crystal alignment properties even if a thermal stress is applied for a long period of time, and a liquid crystal alignment agent having excellent liquid crystal alignment properties, such as disclosed in Patent Document 3, contains a polyamine and a polyamidene having a specific structure. A liquid crystal alignment agent of at least one selected polymer.

However, as the performance of the liquid crystal display element is improved, the characteristics of the liquid crystal alignment film are required to be severe, but it is difficult to meet all the required characteristics only by the prior art.

Prior technical literature Patent literature

Patent Document 1: International Publication No. WO2004/021076 Report

Patent Document 2: International Publication No. WO2013/062115 Report

Patent Document 3: Special Opening 2010-026503

An object of the present invention is to provide a liquid crystal alignment film which is excellent in liquid crystal display element and which has high anti-friction property, which can quickly relax the accumulated electric charge and has high liquid crystal alignment stability.

In order to solve the above problems, the present inventors have intensively reviewed and found that a specific structure can be introduced into a polymer contained in a liquid crystal alignment agent, and various characteristics can be simultaneously improved to complete the present invention.

The present invention is based on the following matters.

A liquid crystal alignment agent comprising a polymer having a structure represented by the following formula (1) in a main chain, (R ₁ represents hydrogen, or a monovalent organic group, and Ar is a phenyl or naphthyl group which may have a substituent; * represents a site bonded to another group).

The liquid crystal alignment film of the present invention can provide a liquid crystal alignment film having excellent rubbing resistance, rapid relaxation of accumulated charges, and high alignment regulation force, and is particularly suitable for a liquid crystal display element for a horizontal electric field driving method, and has an excellent display. Features, especially liquid crystal display elements for horizontal electric field drive.

Form of implementing the invention

The liquid crystal alignment agent of the present invention is a liquid crystal alignment agent containing a polymer having a main chain having a divalent group represented by the following formula (1) (hereinafter also referred to as a specific polymer).

R _{1 of the} formula (1) represents hydrogen or a monovalent organic group. The monovalent organic group is, for example, an alkyl group or an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group, a phenyl group, a fluorine atom, or a group formed by such a combination. Among them, a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms is preferred, and a hydrogen atom or a methyl group is more preferred.

Further, R ₁ may be a securing group which becomes a hydrogen atom by a desorption reaction by heat. From the viewpoint of storage stability of the liquid crystal alignment agent, the protective group is preferably not desorbed at room temperature, but is at 80 ° C or higher, more preferably 100 ° C or higher, and particularly preferably at 150 to 200 ° C to form hydrogen atoms. Things. For example, 1,1-dimethyl-2-chloroethoxycarbonyl, 1,1-dimethyl-2-cyanoethoxycarbonyl, tert-butoxycarbonyl, etc., preferably tert-butoxy Alkylcarbonyl.

Ar of the formula (1) represents a phenyl group or a naphthyl group which may have a substituent, and among these, a phenyl group is preferred. Further, the ring portion of the phenyl or naphthyl group may bond a substituent. Specific examples of the substituent are, for example, a fluorine atom or a methyl group.

The type of the polymer having a divalent group represented by the formula (1) in the main chain of the present invention is not particularly limited. Specifically, it is a polymer for liquid crystal alignment film, such as polyamine, poly-proline, polyphthalate, polyimine, polyurea, polyoxyalkylene, polyester, or the like. Among them, a polymer of at least one of a polyimine precursor such as polyglycolic acid or polyphthalamide or a polyimine obtained by imidization of the oxime is preferred.

The above polyimine precursors, for example, are derived from tetracarboxylic acid derivatives The polyamine or polyphthalate obtained by the diamine reaction. A method of introducing a divalent group represented by the formula (1) into the main chain of the polyimine precursor, for example, a part or all of the tetracarboxylic acid derivative and the diamine used in the above reaction, having a main chain direction A method of at least one selected from the group consisting of a divalent group tetracarboxylic acid derivative represented by the formula (1) and a diamine having a divalent group represented by the formula (1) in the main chain direction.

A tetracarboxylic acid derivative such as a tetracarboxylic acid, a tetracarboxylic dianhydride, a tetracarboxylic acid dihalide, a dicarboxylic acid dialkyl ester or a tetracarboxylic acid dialkyl ester for use in the above polyimide precursor halide. For example, a tetracarboxylic acid having a divalent group represented by the formula (1) in the main chain direction can be represented by the following formula (1-1).

In the formula (1-1), R ₁ and Ar are the same as defined in the above formula (1), and A represents a trivalent group, and two A's may be the same or different. A, for example, a trivalent organic group having at least one selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, a cyclohexane ring structure, a benzene ring structure, and a group of the following formula (A-1) .

Further, the diamine having a divalent group represented by the formula (1) in the main chain direction can be represented by the following formula (1-2).

In the formula (1-2), R ₁ and Ar are the same as defined in the above formula (1), and B represents a single bond or a divalent group, and two B's may be the same or different. When B is a divalent group, it has, for example, a benzene ring structure, an alkyl group having a carbon number of 1 to 10, preferably 1 to 5, an alkenyl structure, an alkoxy structure, a fluoroalkyl structure, and an anthracene. A divalent organic group of at least one selected from the group consisting of amine structures.

Further, the diamine represented by the above formula (1-2) can be used for producing a polyurea having a divalent group represented by the formula (1) in the main chain direction. The polyurea is obtained by reacting a diisocyanate with a diamine, and the polyurea obtained by using part or all of the diamine of the formula (1-2) is a kind of a specific polymer contained in the liquid crystal alignment agent of the present invention. .

The specific polymer used in the present invention is preferably at least one selected from the group consisting of a polyimine precursor containing a structural unit represented by the following formula (2), and a polyimine obtained by ruthenium imidization. One.

In the above formula (2), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative. Y ₁ is a divalent organic group derived from a diamine having a structure of the formula (1) in the main chain direction. R ₂ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₂ is preferably a hydrogen atom, a methyl group or an ethyl group by the viewpoint of heating the imidization.

X ₁ can be appropriately selected depending on the solubility of the polymer with respect to the solvent and the coating property of the liquid crystal alignment agent, and is appropriately selected as the liquid crystal alignment property, the voltage retention ratio, and the accumulated charge when the liquid crystal alignment film is used, and the same The polymer may be one type or two or more types.

Specific examples of X _{1 are} , for example, the structures of the formulae (X-1) to (X-46) disclosed in the items 13 to 14 of International Publication No. 2015/119168.

The following is a preferred X ₁ structure, but the invention is not limited thereto.

Among the above structures, (A-1) and (A-2) are particularly preferable from the viewpoint of further improving the rubbing resistance. (A-4) is particularly preferable from the viewpoint of further increasing the relaxation speed of the accumulated electric charge. (A-15)~(A-17) is particularly preferable from the viewpoint of further improving the liquid crystal alignment property and the relaxation speed of the accumulated charge.

In the formula (2), specific examples of Y _{1 are} , for example, a structure obtained by removing two amine groups from the diamine of the above formula (1-2). Among them, Y _{1 is more} preferably a structure of the following formula (3).

In the formula (3), R ₁ and Ar are the same as defined in the above formula (1). R ₃ represents a single bond or a phenyl group which may have a substituent. * indicates the part bonded to -NH-. R _{3 is} particularly preferably a phenyl group.

The excellent structure of Y ₁ is as follows. In the following formula, Boc represents a tert-butoxycarbonyl group, and * represents a moiety bonded to -NH-.

Further, the diamine having the structure of the above formula (3) is a diamine represented by the following formula (4). The method for producing the diamine will be described later.

In the formula (4), R ₁ and Ar are the same as defined in the above formula (1). R ₃ represents a single bond or a phenyl group which may have a substituent. R _{3 is} particularly preferably a phenyl group.

The polyimine precursor containing the structural unit represented by the formula (2) may contain a structural unit represented by the following formula (5) within the range which does not impair the effects of the present invention.

In the formula (5), X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative. Y ₂ is a divalent organic group derived from a diamine having a structure of Y _{1 in} the formula (1) from the main chain direction. R ₂ is the same as defined in the above formula (2), and R ₄ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Further, it is preferred that at least one of the two R ₄ atoms is a hydrogen atom.

Specific examples of X _2, together with the preferred example, the formula (2) of _an object X enumerated the same structure. Further, Y ₂ is a divalent organic group derived from a diamine having a structure of the formula (1) in the main chain direction, and the structure thereof is not particularly limited. Further, Y ₂ can be appropriately selected depending on the solubility of the polymer with respect to the solvent and the coating property of the liquid crystal alignment agent, and the degree of the liquid crystal alignment property, the voltage holding ratio, and the accumulated charge when the liquid crystal alignment film is used. One or two or more kinds may be used in the same polymer.

Specificity of Y _{2 is} , for example, the structure of the formula (2) disclosed on page 4 of International Publication No. 2015/119168, and the formulas (Y-1) to (Y-97) and (Y-101) disclosed on pages 8 to 12. )~(Y-118); the divalent organic group obtained by removing two amine groups from the formula (2) disclosed on page 6 of International Publication No. 2013/008906; disclosed on page 8 of International Publication No. 2015/122413 The divalent organic group obtained by removing two amine groups from the formula (1); the formula (3) disclosed on page 8 of International Publication No. 2015/060360; and the disclosure of Japanese Laid-Open Patent Publication No. 2012-173514 a divalent organic group obtained by removing two amine groups from the formula (1); a divalent residue obtained by removing two amine groups from the formula (A) to (F) disclosed on page 9 of International Publication No. 2010-050523 Organic base and the like.

The preferred structure of Y ₂ is as follows, but is not limited thereto.

Among the above, (B-28) and (B-29) are particularly preferable in terms of further improving the rubbing resistance. (B-1)~(B-3) is particularly advantageous in terms of further improving the alignment of the liquid crystal. (B-14)~(B-18) and (B-27) are particularly preferable from the viewpoint of further increasing the relaxation speed of the accumulated charge.

The polyimine precursor containing the structural unit represented by the formula (2) is a structural unit represented by the formula (2) when the structural unit represented by the formula (5) is contained, and the structural unit represented by the formula (2) and the formula (5) The total amount is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more.

The polyimine precursor used in the present invention has a good molecular weight of 2,000 to 500,000 and a weight ratio of 5,000 to 300,000. Better, better 10,000~100,000.

The polyimine which has a divalent group represented by the formula (1) in the main chain, for example, a polyimide obtained by ring closure of the aforementioned polyimide precursor. The ring closure ratio (also referred to as the oxime imidization ratio) of the amidino group in the polyimine is not necessarily 100%, and can be arbitrarily adjusted depending on the use and purpose.

A method for imidating a polyimine precursor hydrazine, such as a hydrazine imidization of a solution in which a solution of a polyimide precursor is directly heated, or a catalyst for adding a catalyst to a solution of a polyimide precursor Imine.

The liquid crystal alignment agent of the present invention is one containing the above specific polymer, but may contain two or more specific polymers having different structures. Further, in addition to the specific polymer, another polymer may be contained, that is, a polymer having no divalent group represented by the formula (1) in the main chain. Other types of polymers such as polylysine, polyimine, polyphthalate, polyester, polyamine, polyorganosiloxane, fiber derivatives, polyacetal, polystyrene or Derivatives, poly(styrene-phenylmaleimide) derivatives, poly(meth)acrylates, and the like. When the liquid crystal alignment agent of the present invention contains another polymer, the specific polymer ratio with respect to all the polymer components contained is preferably 5% by mass or more, and for example, 5 to 95% by mass.

The liquid crystal alignment agent is a solution for forming a liquid crystal alignment film, and is generally in the form of a solution. The liquid crystal alignment agent of the present invention is preferably a liquid liquid containing the polymer component and an organic solvent in which the polymer component is dissolved. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed depending on the thickness of the coating film to be formed which is to be formed. The viewpoint of forming a uniform and defect-free coating film is preferably 1% by mass or more, and the preservation stability of the solution is obtained. The viewpoint is preferably 10% by mass or less. A particularly preferred polymer concentration is from 2 to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent may be one which can uniformly dissolve the polymer component, and is not particularly limited. Specifically, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl azine, Γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferably used.

Further, in addition to the above-described solvent, the organic solvent contained in the liquid crystal alignment agent can be generally used in combination with a solvent for improving the coatability of the liquid crystal alignment agent and the surface smoothness of the coating film, and the liquid crystal of the present invention. The type of mixed solvent is suitable for the alignment agent. The organic solvent to be used in combination is, for example, a solvent disclosed in the related art of the liquid crystal alignment agent, for example, the solvent disclosed in the pages [0104] to 55 [0105] of International Publication No. 2015/060357. . The type and content of the solvent can be appropriately selected depending on the coating device of the liquid crystal alignment agent, the coating conditions, the coating environment, and the like.

The liquid crystal alignment agent of the present invention may further contain a component other than the polymer component and the organic solvent insofar as the effect of the present invention is not impaired. Such an additional component is, for example, an adhesion aid for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant, and a crosslinking agent for improving the strength of the liquid crystal alignment film, and adjusting the liquid crystal alignment film. The dielectric material and the conductive material for the dielectric constant and resistance. Specifics of such additional components, for example, related liquids The various materials disclosed in the known literature of the crystal alignment agent are, for example, the components disclosed in pages 53 [0105] to 55 pages [0116] of International Publication No. 2015/060357.

An example of a method of producing a liquid crystal alignment film from the liquid crystal alignment agent of the present invention is to apply a liquid crystal alignment agent in a coating form to a substrate, and then dry and calcine the film, and perform an alignment treatment by a rubbing treatment method or a photo-alignment treatment method. method.

The substrate to which the liquid crystal alignment agent is applied is not particularly limited, and a glass substrate, a tantalum nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. In this case, it is preferable to use a substrate on which an ITO electrode or the like for driving a liquid crystal is formed, which is a step of simplifying the steps. Further, in the reflective liquid crystal display device, an opaque material such as a germanium wafer may be used as the substrate on one side, and a material such as aluminum or the like may be used as the electrode.

The coating method of the liquid crystal alignment agent is not particularly limited, and may be general screen printing, lithography, flexographic printing, inkjet printing, or the like. Other coating methods such as a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray coating method, and the like can be used depending on the purpose.

After the liquid crystal alignment agent is applied onto the substrate, the solvent is evaporated by a heating method such as a hot plate, a heat cycle type oven, or an IR (infrared) type oven to perform baking. The drying and calcining step after coating the liquid crystal alignment agent may be carried out at any temperature and time. Generally, in order to sufficiently remove the solvent contained, for example, it is calcined at 50 to 120 ° C for 1 to 10 minutes, and then calcined at 150 to 300 ° C for 5 to 120 minutes.

The thickness of the liquid crystal alignment film after baking is not particularly limited, but when it is too thin, the reliability of the liquid crystal display element is lowered, and it is preferably 5 to 300 nm, more preferably 10 to 200 nm.

The liquid crystal alignment film of the present invention is suitably used as a liquid crystal alignment film of a liquid crystal display element of a horizontal electric field drive type such as an IPS method or an FFS method, and is particularly preferably used as a liquid crystal alignment film of an FFS liquid crystal display element.

The liquid crystal display element of the present invention is obtained by forming a liquid crystal cell by a known method and then using a liquid crystal cell obtained by using a liquid crystal alignment film obtained by the above liquid crystal alignment agent.

An example of a method of fabricating a liquid crystal cell will be described with respect to a liquid crystal display device having a passive matrix structure. Further, a liquid crystal display element having an active matrix structure of a switching element such as a TFT (Thin Film Transistor) may be provided in each pixel portion constituting the image display.

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, for example, ITO electrodes, and the desired image display can be drawn. Next, an insulating film covering the common electrode and the segment electrode is provided on each of the substrates. The insulating film may be a film formed of, for example, SiO ₂ -TiO ₂ formed by a sol-gel method. Thereafter, a liquid crystal alignment film was formed on each of the substrates under the above-described conditions.

Next, for example, after the ultraviolet curable sealant is placed on a substrate on one of the two substrates forming the liquid crystal alignment film, the liquid crystal is placed on a predetermined number of places on the liquid crystal alignment film surface, and the liquid crystal alignment film is used. For the opposite way, the other substrate is bonded and pressed, and the liquid crystal is wide. The liquid crystal unit is obtained by illuminating the front surface of the liquid crystal alignment film and then irradiating the entire substrate with ultraviolet rays to cure the sealant.

Further, when the liquid crystal alignment film is formed on the substrate, the sealing agent may be placed on a substrate at a predetermined position, and an opening portion through which the liquid crystal may be externally filled may be provided, and the substrate on which the liquid crystal is not disposed is bonded, and then disposed on the sealing agent. The opening portion injects the liquid crystal material into the liquid crystal cell, and thereafter seals the opening portion with an adhesive to obtain a liquid crystal cell. When injecting a liquid crystal material, a vacuum injection method or a capillary phenomenon in the atmosphere may be used.

In any of the above methods, in order to ensure a space in which the liquid crystal material is filled in the liquid crystal cell, it is preferable to use a columnar protrusion on one of the substrates, or to arrange a distance adjustment object on one of the substrates, or to mix the distance adjustment substance into the sealant, or Such combinations and the like.

The above liquid crystal material is, for example, a nematic liquid crystal and a nematic liquid crystal, and among them, a nematic liquid crystal, or a positive liquid crystal material or a negative liquid crystal material may be used. Next, a polarizing plate is provided. Specifically, it is preferable to apply a pair of polarizing plates to the opposite side surfaces of the liquid crystal layers of the two substrates.

Further, the liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above-described contents when the liquid crystal alignment agent of the present invention is used, and may be produced by other known methods. The step of producing a liquid crystal display element from a liquid crystal alignment agent can be disclosed, for example, in JP-A-2015-135393, page 17 [0074] to page 19 [0081].

<Diamine of the invention>

The following describes the manufacture of the above two represented by the following formula (4). Amine method.

In the formula (4), R ₁ and Ar are the same as defined in the above formula (1). R ₃ represents a single bond or a phenyl group which may have a substituent. R _{3 is} particularly preferably a phenyl group.

Preferable specific examples of the diamine represented by the formula (4) are, for example, diamines of the following formulas (4-1) to (4-7). In the formula, Boc represents a tert-butoxycarbonyl group, and Me represents a methyl group.

The method for producing the diamine represented by the above formula (4) is not particularly limited, but a preferred method is as follows.

It is produced by reacting an amine compound (a1) having a thiazole skeleton with a nitro compound (a2) to produce the following dinitro compound (a3). Thereafter, the nitro group is reduced to obtain the desired diamine (a4).

In the above reaction formulas [1] and [2], R' and R" are monovalent organic groups, and X represents a halogen atom, and means fluorine (F), chlorine (Cl), bromine (Br) or iodine (I). atom.

In the above, when R ₁ of the formula (4) is a hydrogen atom, when R ₁ is other than a hydrogen atom, a monovalent organic group corresponding to R ₁ may be introduced into the dinitro compound (a3). When a monovalent organic group is introduced, a compound which can react with an amine, such as an acid halide, an acid anhydride, an isocyanate, an epoxy, a propylene oxide, a halogenated aryl group, or a halogenated alkyl group, can be obtained. Further, an alcohol in which the hydroxyl group of ethanol is substituted with a leaving group such as OMS, OTf or OTs can be used.

The synthesis method of the amine compound (a1) having a thiazole skeleton is not particularly limited, and a general synthesis method can be carried out by reacting an α-haloketone (a5) having a nitro group with thiourea as follows.

A base which can be used, for example, an inorganic base such as sodium hydrogencarbonate, potassium hydrogencarbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate or cesium carbonate, trimethylamine, triethylamine, tripropylamine, triiso a base such as propylamine, tributylamine, diisopropylethylamine, pyridine, quinoline, collidine or the like, sodium hydride or potassium hydride.

As the solvent, a solvent which does not react with the raw material may be used, and an aprotic polar organic solvent (N,N-dimethylformamide, dimethyl hydrazine, N,N-dimethylacetamide, or the like may be used. N-methyl-2-pyrrolidone, etc., ethers (diethyl ether, diisopropyl ether, methyl tert butyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane, etc.), aliphatic hydrocarbons Classes (pentane, hexane, heptane, petroleum ether, etc.), aromatic hydrocarbons (benzene, toluene, xylene, , chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.), halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.), lower fatty acid esters (methyl acetate, acetic acid) Ethyl ester, butyl acetate, methyl propionate, etc., nitrile (acetonitrile, propionitrile, butyronitrile, etc.). The solvent may be appropriately selected in consideration of the reaction or the like, and the above solvents may be used singly or in combination of two or more kinds. Further, a suitable dehydrating agent or a desiccant may be used as the nonaqueous solvent depending on the case. The reaction temperature may be arbitrarily selected from the range of -100 ° C to the boiling point of the solvent to be used, but is preferably in the range of -50 to 150 ° C. The reaction time can be arbitrarily selected within the range of 0.1 to 1000 hours. The product can be purified by recrystallization, distillation, gel column chromatography or the like.

With respect to the above reaction formula [1], when X is fluorine or chlorine, and the NO ₂ group is at the 2- or 4-position relative to X, the halogenated aryl ester can be reacted with the aliphatic amine compound in the presence of a base to obtain a dinitro compound. (a3). The base to be used may be one which uses the aforementioned base. The reaction solvent and the reaction temperature can be as described above. The product can be purified by recrystallization, distillation, gel column chromatography or the like.

Further, when X is bromine or iodine, and the NO ₂ group is 2, 3 or 4 with respect to X, it can be obtained by using a strong metal catalyst, a ligand, and a base in the presence of a base. Dinitrogen. Metal catalysts such as palladium acetate, palladium chloride, palladium chloride-acetonitrile complex, palladium-activated carbon, bis(dibenzylideneacetone)palladium, tris(dibenzylideneacetone)difluorene, bis(acetonitrile) Palladium dichloride, bis(benzonitrile) dichloropalladium, CuCl, CuBr, Cul, CuCN, and the like. The ligand is, for example, triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3 - bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, trimethylphosphite, Triethyl phosphite, triphenyl phosphite, tri-tert-butyl phosphine, and the like. As the base, the aforementioned base can be used. The reaction solvent and the reaction temperature can be as described above. The product can be purified by recrystallization, distillation, gel column chromatography or the like.

The reduction reaction of the above reaction [2] is a hydrogenation reaction in the presence of a catalyst, a reduction reaction under the coexistence of protons, a reduction reaction using formic acid as a hydrogen source, a reduction reaction using hydrazine as a hydrogen source, and the like, and the reduction can be combined. reaction. However, in consideration of the reactivity of the structure of the dinitro compound with the reduction reaction, a hydrogenation reaction is preferred.

The catalyst for the reduction reaction is preferably an activated carbon-supporting metal available from a commercially available product, such as palladium-activated carbon, platinum-activated carbon, ruthenium-activated carbon or the like. Further, it may be a metal catalyst which is not required to be an activated carbon-supporting type such as palladium hydroxide, platinum oxide or Raney nickel. However, it is preferred that palladium-activated carbon, which is generally widely used, yields good results.

In order to carry out the reduction reaction more efficiently, the reaction can be carried out in the presence of activated carbon. The amount of the activated carbon to be used in this case is not particularly limited, but is preferably in the range of 1 to 30% by mass, more preferably 10 to 20% by mass based on the dinitro compound (a3, X1). The reaction can also be carried out under pressure for the same reason. In this case, in order to avoid reduction of the benzene nucleus, it can be carried out under the pressure of 20 Torr. It is also preferred to carry out the reaction in the range of up to 10 atmospheres.

If the solvent is a solvent which does not react with each raw material, it can be used without limitation. For example, an aprotic polar organic solvent (N,N-dimethylformamide, dimethyl hydrazine, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc.); ether can be used; Classes (diethyl ether, diisopropyl ether, methyl tert butyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane, etc.); aliphatic hydrocarbons (pentane, hexane, heptane, petroleum Ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, , chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.; halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, acetic acid) Ethyl ester, butyl acetate, methyl propionate, etc.; nitrile (acetonitrile, propionitrile, butyronitrile, etc.). These solvents may be appropriately selected in consideration of a reaction or the like, and may be used alone or in combination of two or more. The solvent may be dried using a suitable dehydrating agent or a desiccant as necessary, and used as a nonaqueous solvent.

The amount of the solvent (reaction concentration) is not particularly limited, and may be 0.1 to 100 parts by mass, preferably 0.5 to 30 parts by mass, more preferably 1 to 10 parts by mass, per part of the dinitro compound.

The reaction temperature is not particularly limited and may range from -100 ° C to the boiling point of the solvent used, preferably from -50 to 150 ° C. The reaction time is usually from 0.05 to 350 hours, preferably from 0.5 to 100 hours.

The invention will now be described by way of examples and specific examples, but the invention is not limited thereto. Further, the code and characteristic evaluation methods of the following compounds are as follows.

<organic solvent>

NMP: N-methyl-2-pyrrolidone

BCS: butyl cellosolve

DMSO: dimethyl hydrazine

GBL: γ-butyrolactone

Pd/C: palladium carbon

THF: tetrahydrofuran

<additive>

LS-4668: 3-glycidoxypropyltriethoxydecane

(1H-NMR measurement)

Device: Varian NMR system 400 NB (400 MHz) (manufactured by Varian Co., Ltd.), and JMTC-500/54/SS (500 MHz) (manufactured by JEOL Co., Ltd.)

Determination of solvent: CDCl3 (deuterated chloroform), DMSO-d6 (deuterated dimethyl hydrazine)

Reference material: TMS (tetramethyl decane) (δ: 0.0 ppm, 1H) and CDCl3 (δ: 77.0 ppm, 13C)

<Synthetic diamine compound (DA-1)>

2-Bromo-4-nitrophenylethyl benzene (100 g, 410 mmol), sulfur urea (31.2 g, 410 mmol) and NMP (600 g) were placed in a 2 L (liter) four-necked flask, and the temperature was raised to 60 with stirring under stirring. After ° C, triethylamine (83.0 g, 820 mmol) was added dropwise over 10 minutes and stirred for additional 1 hour. After confirming the completion of the reaction by HPLC (High Speed Liquid Chromatography), methanol (1500 g) was added, and the mixture was cooled to 5 ° C and stirred for further 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (200 g), and dried to give crystals (1) (yield: 87 g, yield: 96%).

1H-NMR (CDCl3, δ ppm); 8.25-8.20 (2H, m), 8.10-8.03 (2H, m), 7.42 (1H, s), 7.25 (1H, s)

Compound (1) (50,226 mmol), 4-fluoronitrobenzene (38.3 g, 271 mmol), cesium carbonate (73.6 g, 226 mmol), DMSO (500 g), and water (10 g) were placed in a 1 L four-neck flask. Wing stirring The temperature was raised to 60 ° C and stirred for another 12 hours. Next, cesium carbonate (73.6 g, 226 mmol) was further added and stirred for 12 hours. The obtained reaction liquid was filtered to remove salt, and then methanol (500 g)-water (500 g) was added dropwise thereto, and the mixture was cooled to 5 ° C and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, and then washed with methanol (500 g) for three times, and then dried to obtain powder crystals (2) (yield: 42 g, yield: 54%).

1H-NMR (DMSO-d6, δ ppm); 11.2 (1H, s), 8.30-8.22 (6H, m), 7.98-7.94 (3H, m)

A mixture of the compound (2) (20 g, 29.2 mmol), 5 mass% Pd/C (50% aqueous form) and THF (200 g) was stirred at 60 ° C under hydrogen pressure for 12 hours. After completion of the reaction, the catalyst was filtered, concentrated again, and then the slurry was washed with toluene (200 g). The precipitated crystals were filtered under reduced pressure, washed with toluene (40 g), and dried to give powder crystals DA-1 (yield 16 g, yield 91%).

1H-NMR (DMSO-d6, δ ppm); 9.55 (1H, s), 7.55-7.50 (2H, m), 7.28-7.25 (2H, m), 6.72 (1H, s), 6.58-6.45 (m- 4H), 5.20 (1H, s), 4.82 (2H, s)

<Synthetic Compound (DA-3)>

The 2-amino-6-nitrobenzothiazole of the synthetic raw material can be directly used as a product of Tokyo Chemical Industry Co., Ltd. A mixture of 2-amino-6-nitrobenzothiazole (97.6 g, 0.50 mol), 5 mass% Pd/C (50% aqueous form) and ethanol (3000 g) was stirred at 60 ° C for 12 hours under hydrogen pressure. . After completion of the reaction, the catalyst was filtered and concentrated, and then the obtained crystal was washed with 2-propanol (200 g). After filtration and filtration under reduced pressure, it was washed with 2-propanol (40 g) and then dried to give crystals of DA3 (yield 44.8 g, yield 54%).

<synthetic polymer> [Synthesis Example 1]

DA-1 (2.26 g, 8.0 mmol) was placed in a 50 ml four-necked flask equipped with a stirring device and a nitrogen introduction tube, and 26.0 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-2 (1.57 g, 8.0 mmol) was added, and then NMP 6.5 g was added, followed by stirring at 25 ° C for 12 hours to obtain a polyamic acid solution (PAA) having a resin solid concentration of 12% by mass. -1). The polyamine solution had a viscosity of 300 mPa ‧ s.

[Synthesis Example 2]

Add DA-1 (1.98g, 7.0mmol) to the stirring device and nitrogen guide After introducing a 50 ml four-necked flask into a tube, 23.4 g of NMP was added, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-1 (1.39 g, 6.4 mmol) was added, and then NMP 5.9 g was added, followed by stirring at 50 ° C for 12 hours to obtain a polyamic acid solution (PAA) having a resin solid concentration of 12% by mass. -2). The polyamine solution had a viscosity of 275 mPa ‧ s.

[Synthesis Example 3]

DA-1 (1.81 g, 6.4 mmol) and DA-4 (0.39 g, 1.6 mmol) were placed in a 50 ml four-necked flask equipped with a stirring apparatus and a nitrogen introduction tube, and 20.4 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-2 (0.64 g, 3.3 mmol) was added, and then 2.1 g of NMP was added, followed by stirring at 25 ° C for 1 hour. Thereafter, CA-1 (0.87 g, 4.0 mmol) was added, followed by the addition of 3.0 g of NMP, followed by stirring at 50 ° C for 12 hours to obtain a polyaminic acid solution (PAA-3) having a resin solid concentration of 15% by mass. The polyglycine solution had a viscosity of 593 mPa ‧ s.

[Synthesis Example 4]

After 8.3 g of the polyaminic acid solution (PPA-1) obtained in Synthesis Example 1 was separated, 6.5 g of NMP, 5.2 g of BCS, and 0.8 g of a NMP solution containing 1% by weight of LS-4668 were added thereto with stirring, and then room temperature was added. After stirring for 2 hours, a liquid crystal alignment agent (Q-1) was obtained.

[Synthesis Example 5]

The polyamic acid solution (PPA-2) obtained in Synthesis Example 2 was separated into 10.2 g. Thereafter, 5.8 g of NMP, 5.7 g of BCS, and 1.0 g of a NMP solution containing 1% by weight of LS-4668 were added thereto with stirring, followed by stirring at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-2).

[Synthesis Example 6]

After 7.1 g of the polyaminic acid solution (PPA-3) obtained in Synthesis Example 3 was separated, 4.1 g of NMP 4.1 g, BCS 4.9 g, GBL 7.42 g, and NMP solution containing 1% by weight of LS-4668 were added thereto with stirring. Further, the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-3).

[Comparative Synthesis Example 1]

DA-2 (1.39 g, 7.0 mmol) was placed in a 50 ml four-necked flask equipped with a stirring device and a nitrogen introduction tube, and 19.4 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-2 (1.15 g, 5.9 mmol) was added, and then 4.2 g of NMP was added, followed by stirring at 25 ° C for 12 hours to obtain a polyamic acid solution (PPA) having a resin solid concentration of 12% by mass. -4). The polyaminic acid solution has a viscosity of 280 mPa ‧ s.

[Comparative Synthesis Example 2]

DA-4 (4.89 g, 20.0 mmol) was placed in a 100 ml four-necked flask equipped with a stirring apparatus and a nitrogen introduction tube, and 59.1 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-2 (1.57 g, 8.0 mmol) and CA-1 (2.18 g, 10.0 mmol) were added, then 14.8 g of NMP was added, and the mixture was stirred at 50 ° C for 12 hours to obtain a solid concentration of the resin. 12 Mass % polyaminic acid solution (PPA-5). The polyamine solution had a viscosity of 270 mPa ‧ s.

[Comparative Synthesis Example 3]

DA-3 (1.32 g, 8.0 mmol) was placed in a 50 ml four-necked flask equipped with a stirring device and a nitrogen introduction tube, and 24.6 g of NMP was added thereto, and the mixture was stirred and dissolved while supplying nitrogen. While stirring the diamine solution, CA-1 (1.69 g, 7.8 mmol) was added, and then 6.2 g of NMP was added, followed by stirring at 25 ° C for 12 hours to obtain a polyamic acid solution (PPA) having a resin solid concentration of 10% by mass. -6). The polyamine solution had a viscosity of 150 mPa ‧ s.

[Comparative Synthesis Example 4]

After comparing 10.8 g of the polyamidic acid solution (PPA-4) obtained in Synthesis Example 1, NMP 6.8 g, BCS 6.2 g, and 1.1 g of NMP solution containing 1% by weight of LS-4668 were added thereto with stirring. The mixture was stirred for 2 hours to obtain a liquid crystal alignment agent (Q-4).

[Comparative Synthesis Example 5]

After the 7.3 g of the polyaminic acid solution (PPA-5) obtained in Synthesis Example 2 was separated, 6.8 g of NMP, 4.7 g of BCS, and 0.9 g of a NMP solution containing 1% by weight of LS-4668 were added thereto with stirring. The mixture was stirred for 2 hours to obtain a liquid crystal alignment agent (Q-5).

[Comparative Synthesis Example 6]

After comparing 10.7 g of the polyaminic acid solution (PPA-6) obtained in Synthesis Example 3, 1.5 g of NMP, 5.0 g of BCS, and 1.1 g of NMP solution containing 1% by weight of LS-4668 were added thereto with stirring. The mixture was stirred for 2 hours to obtain a liquid crystal alignment agent (Q-6).

<Measurement of molecular weight of polyimine precursor and ruthenium iodide polymer>

The molecular weight of the polyimine precursor and the ruthenium iodide polymer is a room temperature gel permeation chromatography (GPC) device (GPC-101) (manufactured by Showa Denko Co., Ltd.), and a column (KD-803, KD-805). (manufactured by Shodex Co., Ltd.), measured by the following method.

Column temperature: 50 ° C

Dissolution: N,N'-dimethylformamide (in the additive, lithium bromide-hydrate (LiBr‧H ₂ O) is 30 mmol/L (liter), and anhydrous phosphate crystal (o-phosphoric acid) is 30 mmol/L, Tetrahydrofuran (THF) is 10ml/L)

Flow rate: 1.0ml/min

Standard samples for the production of calibration lines: TSK standard polyethylene oxide (molecular weights of approximately 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weights of approximately 12,000, 4,000 and 1,000) Liman company).

<Measure viscosity>

The viscosity of the polyaminic acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample volume of 1.1 mL and a conical gyrator TE-1 (1° 34', R24) at 25 ° C. .

<Evaluation of friction resistance>

The obtained liquid crystal alignment agent was filtered through a 1.0 μm filter, and then spin-coated on a glass substrate with a transparent electrode, dried on a hot plate at 80 ° C for 5 minutes, and then baked at 230 ° C for 20 minutes to obtain a film thickness of 100 nm.醯 imine film. The polyimine film was rubbed once with rayon (roll diameter: 120 mm, number of revolutions: 1000 rpm, moving speed: 20 mm/sec, and press-in amount: 0.4 mm). The surface state of the surface of the film was observed using a confocal microscope, and the presence or absence of scratches and scratches was observed at a magnification of 100 times. The evaluation method is that the material with almost no shavings and scars is "good", and a large amount of shavings and friction scars are "poor".

<Production of liquid crystal display element>

First, prepare the substrate with the electrode. The substrate was a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. An IZO electrode having a coating pattern as a counter electrode for forming a first layer is formed on the substrate. A SiN (tantalum nitride) film formed by a CVD method as a second layer was formed on the counter electrode for the first layer. The SiN film for the second layer has a film thickness of 500 nm and has an interlayer insulating film function. On the SiN film for the second layer, two kinds of pixels of the first pixel and the second pixel of the comb-shaped pixel electrode formed by patterning the IZO film are formed as the third layer. Each pixel size is 10 mm long by 5 mm wide. At this time, the counter electrode for the first layer and the pixel electrode for the third layer are electrically insulated by the action of the SiN film for the second layer.

The third layer of the pixel electrode and Japan Special Open 2014-77845 In the same manner as the above-described figures, the width of the electrode elements in the comb-tooth shape including the electrode elements of the U-shape in which the central portion of the plurality of columns is curved is 3 μm in the short-side direction, and the interval between the electrode elements is 6 μm. The pixel element forming each pixel is composed of a plurality of electrode elements having a U-shape in which the central portion is curved. Therefore, the shape of each pixel is not rectangular, and the central portion is curved like the electrode element, and has a "ㄑ" shape similar to a bold body. Further, each pixel is divided into upper and lower sides by the central curved portion, and has a first field above the curved portion and a second field below.

Comparing the first field and the second field of each pixel, the electrode elements forming the pixel electrodes are formed in different directions. That is, when the rubbing direction of the liquid crystal alignment film is used as a reference, the electrode elements of the pixel electrode in the first field of the pixel are formed at an angle of +10° (clockwise), and the pixel in the second field of the pixel The electrode elements of the electrodes are formed at an angle of -10° (clockwise). That is, in the first field and the second field of each pixel, the direction of the inversion of the induced liquid crystal in the plane of the substrate (in-plane switching) is caused by the application of a voltage between the pixel electrode and the counter electrode. It is constructed in the opposite direction.

Next, the obtained liquid crystal alignment agent was filtered through a 1.0 μm filter, and each was spin-coated on the prepared substrate of the electrode, and an ITO film was formed on the back surface of the counter substrate, and the columnar pitch was 4 μm high. On the glass substrate. Next, it was dried on a hot plate at 80 ° C for 5 minutes, and then baked at 230 ° C for 20 minutes to form a coating film having a film thickness of 60 nm, thereby forming a polyimide film on each substrate. Rubbing by rayon in a specific rubbing direction (roller diameter 120mm, number of revolutions 500rpm, moving speed 30mm/sec, press-in amount After 0.3 mm of the polyimide film, the ultrasonic wave was irradiated for 1 minute in pure water, and dried at 80 ° C for 1 minute.

Thereafter, the two types of substrates with the liquid crystal alignment film described above were used, and their respective rubbing directions were combined in an anti-parallel manner, and the liquid crystal injection port was sealed under the periphery to form an empty cell having a cell pitch of 3.8 μm. Liquid crystal (MLC-3019, manufactured by Mercury Co., Ltd.) was vacuum-injected into the empty cell at room temperature, and the injection port was sealed to obtain an antiparallel alignment liquid crystal cell. The obtained liquid crystal cell is used for the FFS type liquid crystal display element. Thereafter, the liquid crystal cell was heated at 120 ° C for 1 hour, and left for one night and used for evaluation.

<Evaluation of afterimage erasure time>

The afterimage was evaluated using the following optical system or the like. The liquid crystal cell to be fabricated is placed between two polarizing plates arranged in a straight-line mode, and the LED backlight is lit in a state where no voltage is applied, and the arrangement angle of the liquid crystal cell is adjusted so that the light transmittance is minimized. .

Next, a V-T curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 30 Hz to the liquid crystal cell, and an AC voltage having a relative transmittance of 23% as a driving voltage was calculated.

The afterimage was evaluated by applying an AC voltage of 30 Hz with a relative transmittance of 23% to drive the liquid crystal cell, and applying a DC voltage of 1 V for 30 minutes. Thereafter, only the application of the DC voltage was stopped to apply a DC voltage value of 0 V, and was further driven for 15 minutes in this state.

When the afterimage is evaluated, the DC voltage is applied until 60 minutes have elapsed, and the time when the transmittance is reduced to 30% or less is quantified. Phase When it takes more than 60 minutes for the transmittance to fall below 30%, the definition is that the afterimage cannot be disappeared. Further, when the afterimage was evaluated by the above method, it was carried out under the temperature condition that the temperature of the liquid crystal cell was 23 °C.

<Evaluating Liquid Crystal Alignment Stability>

Using this liquid crystal cell, an alternating voltage of 10 VPP was applied at a cycle number of 30 Hz for 168 hours in a constant temperature environment of 60 °C. Thereafter, in a short-distance state between the pixel electrode and the counter electrode of the liquid crystal cell, it is directly placed at room temperature for one day.

After being placed, the liquid crystal cell is placed between two polarizing plates arranged in a straight-line manner in a polarization mode, and the backlight is turned on without applying a voltage, and the arrangement angle of the liquid crystal cell is adjusted so that the light-transmitting brightness is minimized. Further, the angle of rotation from the angle at which the second field of the first pixel is the darkest, and the angle of the liquid crystal to the darkest angle in the first region is calculated as the angle Δ. The second pixel is also the same, comparing the second field with the first field, and calculating the same angle △. Further, the average value of the angle Δ values of the first pixel and the second pixel is calculated as the angle Δ of the liquid crystal cell. When the angle Δ of the liquid crystal cell is low, it is evaluated as good, and when it is high, it is evaluated as bad.

<Examples 1 to 3>

Using the liquid crystal alignment agents (Q-1 to Q-3) obtained in Synthesis Examples 4 to 6, the abrasion resistance evaluation, the afterimage disappearance time evaluation, and the liquid crystal alignment stability evaluation were performed. The results are shown in Table 1.

<Comparative Examples 1 to 3>

The liquid crystal alignment agents (Q-4 to Q-6) obtained in Comparative Synthesis Examples 4 to 6 were evaluated for each of abrasion resistance, afterimage disappearance time, and liquid crystal alignment stability. The results are shown in Table 1.

From the above results, it is understood that the liquid crystal alignment agent of the present invention can provide a liquid crystal alignment film which simultaneously exhibits excellent rubbing resistance, rapid relaxation of accumulated charges, and high liquid crystal alignment stability.

Industrial use possibility

The liquid crystal alignment agent of the present invention is widely used for forming a liquid crystal display element used in a display unit of a smart phone, a mobile phone, a notebook computer, a television, etc., and particularly a liquid crystal alignment film of a liquid crystal display element of a horizontal electric field type.

Further, the entire contents of the specification, the patent application, the drawings and the abstract of the Japanese Patent Application No. 2015-203278, filed on Oct. 14, 2015, are hereby incorporated by reference.

Claims (10)

A liquid crystal alignment agent characterized by containing a polymer having a structure represented by the following formula (1); (R ₁ is hydrogen, or a monovalent organic group; Ar is a phenyl or naphthyl group which may have a substituent; * means a site bonded to another group). The liquid crystal aligning agent of claim 1, wherein the polymer having a structure represented by the formula (1) in the main chain is a group of polyimine imines obtained by polyamidiamine precursors and their quinone imidization At least one polymer selected. The liquid crystal alignment agent of claim 1 or 2, wherein the polymer is a polyimine precursor containing a structural unit represented by the following formula (2), and a polyimine obtained by imidization At least one polymer, (In the formula (2), X ₁ is a tetravalent organic group; Y ₁ is a divalent organic group having a structure of the formula (1) in the main chain direction; and R ₂ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; ). The liquid crystal alignment agent of claim 3, wherein in the formula (2), Y ₁ has a structure represented by the following formula (3), (R ₁ is hydrogen, or a monovalent organic group; Ar is a phenyl or naphthyl group which may have a substituent; R ₃ represents a single bond, or a phenyl group which may have a substituent; * represents a bond to -NH- Part). The liquid crystal alignment agent of claim 4, wherein the formula (3) is any one of the following formulas (3-1) to (3-7), The liquid crystal alignment agent of claim 3 to 5, wherein the polyimine precursor containing the structural unit represented by the above formula (2) contains a structural unit represented by the following formula (5). (In the formula (5), X ₂ is a tetravalent organic group derived from a tetracarboxylic acid derivative; and Y ₂ is a divalent organic group derived from a diamine having a structure of Y _{1 in} the formula (1) in the main chain direction. ; R ₂ and R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A liquid crystal alignment film obtained by the liquid crystal alignment agent according to any one of claims 1 to 6. A liquid crystal display element comprising the liquid crystal alignment film of claim 7. The liquid crystal display element of claim 8, wherein the liquid crystal display element is in a lateral electric field driving manner. A diamine represented by the following formula (4), (R ₁ is hydrogen, or a monovalent organic group; Ar is a phenyl or naphthyl group which may have a substituent; R ₃ represents a single bond, or a phenyl group which may have a substituent).