CN113045755A

CN113045755A - Alignment film material, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: CN113045755A
Application number: CN202110296853.4A
Authority: CN
Inventors: 李晗; 梁为民; 游石枝
Original assignee: Shenzhen Qinghe Technology Co ltd
Current assignee: Shenzhen Qinghe Technology Co ltd
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2021-06-29
Anticipated expiration: 2041-03-19
Also published as: CN113045755B

Abstract

The invention discloses an orientation film material, a liquid crystal orientation agent, a liquid crystal orientation film and a liquid crystal display element, and belongs to the technical field of liquid crystal display. The liquid crystal film material comprises a tetracarboxylic dianhydride component a and a diamine component b, wherein the diamine component b at least comprises

Description

Alignment film material, liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Technical Field

The invention relates to an orientation film material, a liquid crystal orientation agent, a liquid crystal orientation film and a liquid crystal display element, and belongs to the technical field of liquid crystal display.

Background

As liquid crystal display elements, liquid crystal display elements of various driving methods such as a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, an IPS (In-Plane Switching) mode, an FFS (fringe field Switching) mode, and a vertically aligned VA (multi-domain vertical alignment) mode are known. These liquid crystal display elements are applied to image display devices of various electronic devices such as televisions and cellular phones, and are being developed to further improve display quality. Specifically, the performance of the liquid crystal display element can be improved not only by improving the driving method and the element structure but also by using the constituent members for the element. Among the components used in liquid crystal display devices, liquid crystal alignment films are one of the important components related to display quality, and in response to the demand for high quality of liquid crystal display devices, research into such liquid crystal alignment films has been intensively conducted.

In recent years, as the amount of liquid crystal products to be held increases and their use advances, higher demands have been made on the display quality of liquid crystal products, and some of the well-known defects, mainly including poor alignment of liquid crystals, low contrast, severe afterimage, and a decrease in the voltage holding ratio (hereinafter abbreviated as "VHR") of display elements, high ion density, easy accumulation of charges, and a slow release rate of accumulated charges, have been recognized and attracted attention.

With the recent expansion of the application range of LCDs, an afterimage phenomenon, which macroscopically shows that when the LCD displays the same screen for a long time and then switches the screen, the original screen remains in the next screen, occurs in many cases. The principle of afterimage generation is that positive and negative ions in the liquid crystal box are respectively collected at two ends of the liquid crystal box under the action of an external electric field, and when the external electric field is closed, a reverse electric field can be formed in the liquid crystal box due to the fact that the ions can not be rapidly dispersed, and afterimages are formed. Therefore, with the increasing requirements on the display image quality and the production line yield, the requirements on the good afterimage performance of the liquid crystal orientation film are more and more strict.

One of the important reasons for the generation of the afterimage is the influence of the ion content in the liquid crystal aligning agent, and particularly, the accumulation of sodium and potassium ions has a great influence on the reduction of the voltage holding ratio (hereinafter, abbreviated as VHR) of the liquid crystal display element, so that the afterimage generation is very important, and if the ions can reach the positive electrode and the negative electrode of the power supply in time, the voltage holding ratio can be greatly improved.

Disclosure of Invention

It is an object of the present invention to find a novel liquid crystal alignment film structure which is less likely to cause a decrease in voltage holding ratio due to a light irradiation reaction when applied to a liquid crystal display device and which can realize high contrast and clear bright and dark display satisfying recent requirements.

The liquid crystal aligning agent provided by the invention has a crucial inhibiting effect on the generation of residual images due to the carbazole structure contained in the liquid crystal aligning agent to disperse ions, particularly sodium ions and potassium ions in the liquid crystal aligning agent. The prepared liquid crystal display element has the characteristic of good afterimage; and also suppresses a decrease in display contrast due to long-time lighting.

The technical scheme for solving the technical problems is as follows:

a liquid crystal alignment film material comprising a polymer a and a solvent B obtained by reacting a mixture, wherein the mixture comprises a tetracarboxylic dianhydride component a and a diamine component B, the diamine component B comprises at least a diamine compound B-1 represented by formula 1, the diamine compound B-1 has the following structural formula:

x in formula 1: -O-,

-CO-、-S-、-O-CO-、-NH-CO-、-O-(CH₂) m- (m is independently an integer of 1-12), and R is methyl or hydrogen.

Further, the polymer A is one or a mixture of two of polyamic acid and polyimide.

Further, the diamine compound b-1 may be exemplified by a mixture of one or more of the formulae 1-1 to 1-7.

The tail end of the orientation agent has carbazole, so that the rigidity structure of molecules is increased, and the pre-inclination angle is improved. Thus, a liquid crystal alignment film having high light stability and exhibiting good liquid crystal alignment properties can be formed.

Further, the tetracarboxylic dianhydride component a is one or more of 1,2,3, 4-cyclobutane tetracarboxylic dianhydride, pyromellitic dianhydride, 2,3, 5-tricarboxycyclopentyl acetic dianhydride and 3,3 ', 4, 4' -biphenyl tetracarboxylic dianhydride;

the diamine b also comprises b-2, and the b-2 is one or more selected from p-phenylenediamine, 1, 2-bis (4-aminophenoxy) ethane, p-aminophenylethylamine, 3, 5-diaminobenzoic acid, N ' -bis (4-aminophenyl) piperazine, 4 ' -diaminobenzamide, 4 ' -diaminodiphenylethane, 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene and 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate.

The invention also discloses an aligning agent, which comprises a conducting layer polymer and an aligning layer polymer, wherein the conducting layer polymer is selected from the liquid crystal film material, the aligning layer polymer is selected from imidized polyimide synthesized by a tetracarboxylic dianhydride component a and a diamine component b, and the molar percentage of the strong polar diamine compound b-1 in the diamine component b is 20-60%.

Further, the diamine compound b in the alignment layer polymer also comprises long-side-chain diamine, wherein the long-side-chain diamine is 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene, and the mole percentage of the long-side-chain diamine in the diamine component b is 40-90%, preferably 60-80%.

A liquid crystal alignment film uses the liquid crystal alignment agent. The liquid crystal orientation film comprises an orientation layer and a conductive layer, wherein the number average molecular weight Mn of a conductive layer polymer used by the conductive layer is 25000-50000 g/mol, and the number average molecular weight Mn of an orientation layer polymer used by the orientation layer is 7500-15000 g/mol.

The liquid crystal alignment film of the present invention has a two-layer PI structure as compared with conventional alignment agents, polyimide synthesized by diamine and dianhydride is used as the upper layer of PI, p-phenylenediamine, 1, 2-bis (4-aminophenoxy) ethane, p-aminophenylethylamine, 3, 5-diaminobenzoic acid, N ' -bis (4-aminophenyl) piperazine, 4 ' -diaminobenzamide, 4 ' -diaminodiphenylethane, 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene, 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate are preferable as the upper layer of PI, imide acid synthesized by diamine and dianhydride is used as the lower layer of the alignment layer. Diamine contains a high-polarity b-1 structure, is used as a conductive layer, has excellent dispersing capacity of sodium ions and potassium ions, and the prepared liquid crystal display element has the characteristic of good afterimage property; and also suppresses a decrease in display contrast due to long-time lighting. Therefore, the liquid crystal orientation film and the liquid crystal display element prepared by the liquid crystal orientation agent have good afterimage and high contrast.

The preparation method of the polyimide acid can adopt a conventional method and comprises the following steps: the mixture comprising the tetracarboxylic dianhydride component a and the diamine component b is first dissolved in a solvent and subjected to a polymerization reaction at a temperature of 0 to 100 ℃ for 1 to 24 hours to obtain a polyamic acid solution, and then the solvent may be distilled off under reduced pressure to obtain a polyamic acid solid, or the reaction system may be poured into a large amount of a poor solvent and the precipitate dried to obtain a polyamic acid solid.

Further, the alignment layer polymer of the present invention contains at least one polymer selected from the group consisting of polyimide acids obtained by reacting a tetracarboxylic dianhydride component a and a diamine component b, and the polyimide is obtained by reacting the polyamic acid with acetic anhydride and pyridine, dehydrating and imidizing.

Further, the solvent component is one or more of N-methyl-2-pyrrolidone, gamma-butyrolactone, N-dimethylformamide, N-dimethylacetamide, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol dimethyl ether and diethylene glycol monomethyl ether ethyl ester.

Further, in the liquid crystal alignment liquid composed of the polymer and the solvent component, the weight ratio of the polymer is 1% to 40%, more preferably 5% to 20%.

When the weight ratio of the polymer is less than 5%, the film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film, while when the weight ratio of the polymer exceeds 20%, the film thickness of the coating film becomes too large to obtain a good liquid crystal alignment film, and therefore, it is more preferably 5% to 20%.

Further, the tetracarboxylic dianhydride component a is one or more of 1,2,3, 4-cyclobutane tetracarboxylic dianhydride, 2,3, 5-tricarboxycyclopentyl acetic dianhydride, pyromellitic dianhydride and 3,3 ', 4, 4' -biphenyl tetracarboxylic dianhydride.

Further, the alignment layer diamine component b includes a diamine compound b-2, and the diamine compound b-2 is one or more of p-phenylenediamine, 1, 2-bis (4-aminophenoxy) ethane, p-aminophenylethylamine, 3, 5-diaminobenzoic acid, N ' -bis (4-aminophenyl) piperazine, 4 ' -diaminobenzamide, 4 ' -diaminodiphenylethane, 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene, 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate.

Further, the molar ratio of the tetracarboxylic dianhydride component a to the diamine component b is 100: 10-200, more preferably 100: 50-100 percent, wherein the long-chain diamine 1- (4- (4-heptyl cyclohexyl) phenoxy) -2, 4-diaminobenzene accounts for 70-90 percent.

Further, in the diamine component b of the conductive layer, the percentage molar ratio of the diamine compound b-1 is 0.5 to 100 mol%, and more preferably 20 to 60 mol%.

The solvent component is one or more of N-methyl-2-pyrrolidone, gamma-butyrolactone, N-dimethylformamide, N-dimethylacetamide, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol dimethyl ether and diethylene glycol monomethyl ether ethyl ester.

Further, the solvent used for the polymerization reaction may be the same as or different from the solvent in the liquid crystal aligning agent, and the solvent used for the polymerization reaction is not particularly limited as long as it can dissolve the reactants. Solvents for the polymerization reaction include, but are not limited to, N-methyl-2-pyrrolidone, N-dimethylacetamide, N-dimethylformamide, γ -butyrolactone. Wherein, in a reaction liquid composed of a reaction mixture obtained by mixing the tetracarboxylic dianhydride component a and the diamine component b and the solvent, the weight ratio of the reaction mixture in the reaction liquid is 1-50%, and more preferably 10-30%.

Further, the solvent component comprises a poor solvent which does not cause polymer precipitation, the poor solvent comprises one or more of methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, tetrahydrofuran, dichloromethane, chlorobenzene, 1, 2-dichloroethane, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclobutanone, methyl acetate, ethyl acetate, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol methyl ethyl ether and ethylene glycol dimethyl ether, and the poor solvent accounts for 0-70% of the total weight of the solvent component, preferably 15-50% of the total weight of the solvent.

The preparation method of the polyimide can adopt, but is not limited to, the following two imidization methods, namely a thermal imidization method or a chemical imidization method.

The thermal imidization method is to directly heat and dehydrate the polyimide solid into a ring, and the heating temperature is preferably 150-300 ℃.

The chemical imidization method comprises the following steps: the polyamic acid is dehydrated and ring-closed at a lower temperature in the presence of a dehydrating agent and a catalyst to prepare the polyimide.

The solvent for the imidization reaction may be the same as that in the liquid crystal aligning agent.

Wherein the weight ratio of the polyamic acid to the imidization solvent is 1: 5-25; imidization rate of polyamic acid is 10-100%; the temperature of imidization reaction is 0-120 ℃, and more preferably 40-80 ℃; the reaction time is 1 to 100 hours, more preferably 4 to 10 hours; the dehydrating agent can be selected from an acid anhydride compound, such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride; the molar ratio of the raw material tetracarboxylic dianhydride and the dehydrating agent used in the polyamic acid is preferably 1:0.5 to 10, more preferably 1: 1-5; the catalyst can be selected from pyridine, 4-methylpyridine, trimethylamine or triethylamine; the molar ratio of the dehydrating agent to the catalyst is 1:0.5 to 5, more preferably 1: 2-4.

Further, a molecular weight regulator is added in the synthesis of the polymer, the molecular weight regulator comprises one or more of aniline, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, phenyl isocyanate, naphthyl isocyanate, maleic anhydride, phthalic anhydride, o-cyclohexanedicarboxylic anhydride and succinic anhydride, and the molar ratio of the molecular weight regulator to the tetracarboxylic dianhydride component a is 0.001-20: 100. preferably, the molar ratio of the molecular weight regulator to the tetracarboxylic dianhydride component a is from 0.4 to 8: 100, the molecular weight of the polymer is adjusted by adding a molecular weight regulator in the synthesis process of the polymer, the number average molecular weight of the orientation layer is kept at 7500-15000 g/mol, and the number average molecular weight of the conductive layer is 25000-50000 g/mol, so that the feasibility of a subsequent coating process is ensured.

The number average molecular weight means the number average molecular weight in terms of polystyrene measured by the GPC method. In determining the number average molecular weight according to polystyrene measured by the GPC method, a conventionally known analysis apparatus, a detector (e.g., a refractive index detector), and an analytical column may be used. Commonly applied temperature, solvent and flow conditions may be used. Specific examples of the measurement conditions are as follows: using a watersp pl-GPC220 instrument, a sample was prepared at a concentration of 10mg/10mL using a polymer laboratory sp lgel mix-B300mm column at an evaluation temperature of 160 ℃ using 1,2, 4-trichlorobenzene as a solvent at a flow rate of 1 mL/min and then fed in an amount of 200 μ L, and the value of Mn can be determined using a calibration curve formed from polystyrene standards. The molecular weights of the polystyrene standards used herein were nine:

2000/10,000/30,000/70,000/200,000/700,000/2,000,000/4,000,000/10,000,000。

further, the additive comprises an epoxy additive and/or a silane compound additive with functional groups, wherein the addition amount of the epoxy additive is 0.01-10% of the total weight of the polymer, preferably, the addition amount of the epoxy additive is 0.5-8% of the total weight of the polymer, the addition amount of the silane compound additive with functional groups is 0.01-10% of the total weight of the polymer, preferably, the addition amount of the silane compound additive with functional groups is 0.5-5% of the total weight of the polymer;

the epoxy additive is one or more of polypropylene glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerol diglycidyl ether, N, N, N ', N ' -tetracyclooxypropyl-4, 4 ' -diaminodiphenylmethane or 3- (N, N-diglycidyl) aminopropyltrimethoxysilane;

the silane compound additive with functional groups is one or more of N- (2-aminoethyl) -3-aminopropyl-methyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl-trimethoxysilane, 3-aminopropyl-triethoxysilane, 2-aminopropyl-trimethoxysilane, 3-aminopropyl-triethoxysilane, N-phenyl-3-aminopropyl-trimethoxysilane or N-bis (ethylene oxide) -3-aminopropyl-triethoxysilane. The additive functions to increase the stability of the liquid crystal alignment film or to improve the adhesion between the liquid crystal alignment film and the substrate, and the liquid crystal alignment agent can be prepared by mixing the polymer and the additive in a solvent at 10 to 100 ℃ under stirring, more preferably 30 to 70 ℃.

The liquid crystal aligning agent of the invention is a double-layer PI structure, the upper layer of PI is formed by diamine and dianhydride (preferably 2,3, 5-tricarboxycyclopentyl acetic acid dianhydride) to synthesize polyamic acid, and then the polyamic acid is reacted with acetic anhydride and pyridine to generate imidized polyimide, diamine b is preferably p-phenylenediamine, 1, 2-bis (4-aminophenoxy) ethane, p-aminophenylethylamine, 3, 5-diaminobenzoic acid, N ' -bis (4-aminophenyl) piperazine, 4 ' -diaminobenzamide, 4 ' -diaminodiphenylethane, 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene, 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate, wherein 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene accounts for more than 60 percent and is used as an orientation layer; the lower layer is imide acid synthesized by diamine and dianhydride (preferably pyromellitic dianhydride and 3,3 ', 4, 4' -biphenyl tetracarboxylic dianhydride), the diamine contains a high-polarity b-1 structure, is used as a conductive layer, has excellent ion dispersion capability, and the prepared liquid crystal display element has the characteristic of good afterimage; and also suppresses a decrease in display contrast due to long-time lighting. Thus, a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be formed, the service life of the product can be increased, and a high-quality liquid crystal display element can be obtained.

The invention also provides an application of the liquid crystal orientation agent in a liquid crystal orientation film, and the liquid crystal orientation film is prepared by using the liquid crystal orientation agent.

The preparation method of the liquid crystal orientation film comprises the following steps:

coating, namely coating the substrate after the alignment layer polymer and the conducting layer polymer are dissolved by using a mixed solvent, and standing the substrate after coating to separate the alignment layer polymer and the conducting layer polymer;

an alignment step of applying anisotropy to the liquid crystal alignment layer film by irradiating the liquid crystal alignment layer film with light;

a heat curing step of heat curing the film of the liquid crystal alignment agent having anisotropy;

preparing a void cell, orienting the alignment films formed on the upper and lower plates such that they face each other and the orientation directions are aligned with each other, and then bonding the upper and lower plates together and UV-curing and thermally curing the sealant to prepare a void cell;

the liquid crystal was injected into the empty cell, and the injection port was sealed with a sealant to prepare a structural unit of a liquid crystal phase taking film.

A liquid crystal display element comprises the liquid crystal orientation film.

Hereinafter, an example of a method for forming a liquid crystal alignment film by using the liquid crystal alignment agent for photo-alignment (liquid crystal alignment agent) of the present invention will be described in detail.

(step 1: formation of coating film)

First, a liquid crystal aligning agent is applied to a substrate, and preferably, the applied surface is heated, thereby forming a coating film on the substrate. As the substrate, for example: float glass, soda lime glass, and the like; transparent substrates comprising plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly (alicyclic olefin). As the transparent conductive film provided on one surface of the substrate, a NESA (NESA) film containing tin oxide (SnO2), an Indium Tin Oxide (ITO) film containing indium oxide-tin oxide (In2O3-SnO2), or the like can be used. In the case of manufacturing a TN-type, STN-type, or VA-type liquid crystal cell, two substrates provided with a patterned transparent conductive film are used. On the other hand, in the case of manufacturing an IPS-type or FFS-type liquid crystal element, a substrate provided with an electrode including a transparent conductive film or a metal film patterned into a comb-tooth shape and an opposing substrate provided with no electrode are used. As the metal film, for example, a film containing a metal such as chromium can be used. The liquid crystal aligning agent is preferably applied to the substrate by a lithographic method, a flexographic printing method, a spin coating method, a roll coater method or an ink jet method on the electrode forming surface. After the liquid crystal aligning agent is applied, preheating (prebake) is preferably performed for the purpose of preventing sagging of the applied liquid crystal aligning agent, and the like. The pre-baking temperature is preferably 30-200 ℃, and the pre-baking time is preferably 0.25-10 minutes. Thereafter, the solvent is completely removed, and a calcination (postbake) step is performed as necessary for the purpose of thermal imidization of the amic acid structure present in the polymer. The calcination temperature (post-baking temperature) in this case is preferably 80 to 300 ℃, and the post-baking time is preferably 5 to 200 minutes. The film formed in this way preferably has a thickness of 0.001 to 1 μm. After the liquid crystal alignment agent is applied to the substrate, the organic solvent is removed, thereby forming a liquid crystal alignment film or a coating film to be the liquid crystal alignment film.

Step 2: orientation treatment

In the case of producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal cell, a treatment (alignment treatment) is performed to impart liquid crystal alignment ability to the coating film formed in the above-described step 1. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. As the alignment treatment, a photo-alignment treatment in which a coating film formed on a substrate is irradiated with light to impart liquid crystal alignment ability to the coating film can be preferably used in terms of high photosensitivity of the polymer (P) and anisotropy of the coating film can be exhibited even with a small exposure amount. On the other hand, in the case of producing a vertical alignment type liquid crystal element, the coating film formed in the above step 1 may be used as it is as a liquid crystal alignment film, but the coating film may also be subjected to an alignment treatment.

The light irradiation in the photo-alignment treatment can be performed by the following method or the like: a method of irradiating a coating film after the post-baking step, a method of irradiating a coating film after the pre-baking step and before the post-baking step, and a method of irradiating a coating film during heating of a coating film in at least any one of the pre-baking step and the post-baking step. In the photo-alignment treatment, as the radiation to be irradiated to the coating film, for example, ultraviolet rays and visible rays including light having a wavelength of 150nm to 800nm can be used. Preferably, the ultraviolet light contains light having a wavelength of 200nm to 400 nm. In the case where the radiation is polarized light, it may be linearly polarized light or partially polarized light. When the radiation used is linearly polarized light or partially polarized light, the irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination thereof. When unpolarized radiation is irradiated, the irradiation direction is set to be an oblique direction.

As the light source used, for example, there can be used: low pressure mercury lamps, high pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, and the like. The irradiation dose of the radiation is preferably 400J/m2 to 20,000J/m2, more preferably 1,000J/m2 to 5,000J/m 2. In order to improve the reactivity, the coating film may be irradiated with light while being heated.

The production of the liquid crystal alignment film may further comprise a contacting step of contacting the coating film subjected to the light irradiation treatment with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. By performing such a contact step, a decomposed product generated by the photo-alignment treatment can be removed from the film, and it is preferable in that the occurrence of minute bright spots in the obtained liquid crystal element can be suppressed. Examples of the water-soluble organic solvent include: methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Of these, the solvent used in the contacting step is preferably water, isopropyl alcohol, or a mixture of these.

Examples of the method of contacting the coating film with the solvent include: spraying (spray), showering, dipping, coating, etc., but are not limited thereto. The contact time of the coating film with the solvent is not particularly limited, and is, for example, 5 seconds to 15 minutes. The temperature at which the coating film is brought into contact with the solvent is, for example, 10 ℃ to 30 ℃.

When the liquid crystal alignment film is manufactured, a heating step may be further performed: heating the coating film subjected to the light irradiation treatment in a temperature range of 120 ℃ to 280 ℃ before or after the contacting step. By performing such a heating step, the liquid crystal alignment property is further improved, and it is preferable in terms of obtaining a liquid crystal element with further reduced AC image sticking.

The heating temperature in the heating step is preferably 140 ℃ or higher, and more preferably 150 to 250 ℃, in terms of promoting the reorientation of the molecular chains by heating. The heating time is preferably 5 minutes to 200 minutes, more preferably 10 minutes to 60 minutes.

And step 3: construction of liquid crystal cell

Two substrates on which liquid crystal alignment films are formed in this manner are prepared, and liquid crystal is disposed between the two substrates disposed to face each other, thereby manufacturing a liquid crystal cell. Examples of the liquid crystal cell include: (1) a method in which two substrates are placed in opposition to each other with a gap (spacer) therebetween so that liquid crystal alignment films face each other, peripheral portions of the two substrates are bonded to each other with a sealant, and a liquid crystal is injected and filled into a cell gap defined by a substrate surface and the sealant, and then the injection hole is sealed, a method in which (2) the sealant is applied to a predetermined position on one of the substrates on which the liquid crystal alignment films are formed, and further, the liquid crystal is dropped onto predetermined places on the liquid crystal alignment film surface, and then, the other substrate is bonded to face each other so that the liquid crystal alignment films face each other, and the liquid crystal is diffused over the entire surface of the substrates (an One Drop Fill (ODF) method), and the like. It is desirable that the liquid crystal cell to be manufactured is further heated to a temperature at which the liquid crystal to be used becomes an isotropic phase, and then slowly cooled to room temperature, thereby removing the flow alignment at the time of filling the liquid crystal.

As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used. As the spacer, a photo spacer (photospacer), a bead spacer (bead), or the like can be used. Examples of the liquid crystal include nematic liquid crystals and smectic liquid crystals, and among them, nematic liquid crystals are preferable, and examples thereof include schiff base (Schiffbase) -based liquid crystals, azoxy-based liquid crystals, biphenyl-based liquid crystals, phenylcyclohexane-based liquid crystals, ester-based liquid crystals, terphenyl-based liquid crystals, diphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, and cubic alkane-based liquid crystals. In addition, for example, a cholesteric liquid crystal (cholesteric liquid crystal), a chiral agent, a ferroelectric liquid crystal (ferroelectric liquid crystal), or the like may be added to these liquid crystals. Next, a polarizing plate is attached to the outer surface of the liquid crystal cell as necessary. Examples of the polarizing plate include a polarizing plate in which a polarizing film called an "H film" in which iodine is absorbed while polyvinyl alcohol is stretched and oriented, is sandwiched between cellulose acetate protective films, and a polarizing plate including an H film itself. Thereby obtaining a liquid crystal cell.

The invention has the following beneficial effects:

the polymer of the liquid crystal orientation film material contains a high-polarity carbazole structure, has good dispersion effect on ions in a liquid crystal orientation agent, particularly sodium ions and potassium ions, and can effectively inhibit the generation of afterimages. The liquid crystal display element prepared by the method has good afterimage resistance, can effectively avoid the problem of display contrast reduction caused by long-time lighting, can maintain extremely high voltage retention rate under long-time exposure to illumination conditions, has high contrast and clear bright and dark display, can effectively improve the picture display quality of the liquid crystal display element, prolongs the service life of a product, and can prepare a high-quality liquid crystal display element.

Detailed Description

The present invention will be described in detail with reference to examples, which are only preferred embodiments of the present invention and are not intended to limit the present invention.

[ evaluation of reliability of Voltage Holding Ratio (VHR) ]

The Voltage Holding Ratio (VHR) of the electrical characteristics of the liquid crystal alignment cell was measured using a 6254C apparatus of TOYO corporation. The voltage holding ratio was measured under the conditions of 1Hz and 60 ℃.

[ measurement of AC residual image and contrast (evaluation of liquid Crystal alignment) ]

Polarizers are attached to the upper and lower plates of the liquid crystal cell such that their polarization axes are perpendicular to each other. The liquid crystal cell was adhered to 7000cd/m²Using PR755, the luminance in the black mode was measured. The liquid crystal cell was then driven at 5V AC voltage for 24 hours at room temperature. Thereafter, the luminance in the black mode is measured in the same manner as described above in a state where the voltage of the liquid crystal cell is turned off. The difference between the handling luminance (L0) measured before driving the liquid crystal cell and the luminance (L1) after driving the liquid crystal cell was divided by the initial luminance (L0) and multiplied by 100 to characterize the change in luminance. The smaller this value, the more excellent the surface orientation stability. The level of AC afterimage was evaluated by measuring the variation value of the luminance according to the following criteria. In the measurement results, if the variation value is less than 5%, it is evaluated as "excellent"; if the brightness change value is 5% -10%, the evaluation is 'good'; the evaluation is 'normal' if the variation value is 10% -20%; if it is notThe luminance change value is greater than 20%, and evaluated as "poor".

Evaluation of Long-term Heat resistance (minute Brightness failure)

A liquid crystal cell was produced in the same manner as described above, except that the polarizing plates were not bonded to both outer sides of the substrates. After the obtained liquid crystal cell was kept in a constant temperature bath at 100 ℃ for 20 days, the presence or absence of minute bright points in the liquid crystal cell was observed by a microscope, whereby evaluation of the minute bright points was performed. It is known that, in the case where a decomposed product generated by light irradiation for photo-alignment treatment remains in a film, the decomposed product oozes out of the film surface by exposing a liquid crystal display element to a high-temperature environment for a long time, and is gradually crystallized in a liquid crystal, and observed as a minute bright point. The observation was carried out at 680. mu. m.times.680 μm under a microscope magnification of 100 times. For the evaluation, the case where no fine bright spots were observed was regarded as "good", the case where the number of fine bright spots was 1 dot or more and 5 dots or less was regarded as "good", the case where the number of fine bright spots was 6 dots or more and 10 dots or less was regarded as "ok", and the case where the number of fine bright spots was 11 dots or more was regarded as "bad". As a result, the evaluation in the examples was "good".

Compounds and solvents used

The diamine used for preparing the polymer in this example was classified as a photoreactive diamine having thermal reactivity.

Tetracarboxylic acid dianhydride

a-1: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride

a-2: 2,3, 5-tricarboxylic cyclopentyl acetic dianhydride

a-3: pyromellitic dianhydride

a-4: 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride

Diamines

b-2-1: p-phenylenediamine

b-2-2: 1, 2-bis (4-aminophenoxy) ethane

b-2-3: p-aminophenylethylamine

b-2-4: 3, 5-diaminobenzoic acid

b-2-5N, N' -bis (4-aminophenyl) piperazine

b-2-6: 4, 4' -diaminobenzamides

b-2-7: 4, 4' -diaminodiphenylethane

b-2-8: 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene

b-2-9: 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate

The conductive layer of the alignment film contains diamine b-1 of

Solvent:

NMP: n-methyl-2-pyrrolidone

BC: butyl Cellosolve (ethylene glycol monobutyl ether)

Synthesis example of Compound

Synthetic route to b-1

(1) Synthesis of b-1-1

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol (1.21g 0.5mmol) were added to compound a (2.63g 10mmol) and compound b phenylboronic acid (1.21g 10mmol) to react for 12 hours at 90 ℃ under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-1a (1.44g) as a white solid in 67.0% yield, which was measured by HPLC-MS (M +1) ═ 215.07.

(2) Synthesis of b-1-1b

Taking the compound b-1-1a (2.14g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. The product was isolated by PE/EA column chromatography in 56.6% yield as an off-white solid, b-1-1b (1.2g), and HPLC-MS (M +1) ═ 213.05 was determined for the product.

(3) Synthesis of b-1-1c

Compound b-1-1b (2.12g, 10mmol), di-tert-butyl dicarbonate (2.18g, 10mmol), triethylamine (5ml), and ethanol (100ml) were reacted at room temperature in a 250ml three-necked flask for 12 hours. Detecting the reaction progress by TLC, after the reaction is finished, filtering to remove salt, extracting by EA, washing for 5 times by saturated saline solution, and removing the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-1c (2.53g) as a pale yellow solid in 81.1% yield and HPLC-MS (M +1) ═ 313.11.

(4) Synthesis of b-1-1d

Compound b-1-1c (3.03g 10mmol), 4-amino-3-iodobenzoyl chloride (2.8g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product as yellow b-1-1d (3.84g) in 69.0% yield as HPLC-MS (M +1) ═ 558.04.

(5) Synthesis of b-1-1e

The compound b-1-1d (5.48g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. Column chromatography on PE/EA afforded the product b-1-1e (2.84g) as a black solid in 64.4% yield, which was determined by HPLC-MS (M +1) ═ 451.09.

(6) Synthesis of b-1

Compound b-1-1e (4.51g 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. Column chromatography on PE/EA afforded the product b-1(2.2g) as a black solid in 57.7% yield, which was measured by HPLC-MS (M +1) ═ 391.15. Elemental analysis: theoretical value C, 76.91; h, 4.65; n, 14.35; o, 4.10; measured value: c, 76.90; h, 4.66; n, 14.34; and O, 4.11.

Synthetic route to b-1-2

(1) Synthesis of b-1-2a

The compound a (2.63g 10mmol) and the compound a phenylboronic acid (1.21g 10mmol) were placed in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-2a (1.35g) as a white solid in 47.0% yield, which was measured by HPLC-MS (M +1) ═ 215.22.

(2) Synthesis of b-1-2b

Taking the compound b-1-1a (2.15g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-2b (1.6g) as a white solid in 54.4% yield, which was measured by HPLC-MS (M +1) ═ 213.20.

(3) Synthesis of b-1-2c

Taking a compound b-1-2b (2.12g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-2c (1.65g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 227.07.

(4) Synthesis of b-1-2d

Compound b-1-c (2.26g 10mmol), 4-amino-3-iodobenzoyl chloride (2.8g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-2d (4.84g) as a grey solid in 75.6% yield as measured by HPLC-MS (M +1) ═ 346.35.

(5) Synthesis of b-1-2e

The compound b-1-2d (3.46g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-2e (4.84g) as a dark gray solid in 78.8% yield and 465.43% by HPLC-MS (M + 1).

(6) Synthesis of b-1-2f

Taking the compound b-1-2e (4.65g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. Column chromatography on PE/EA afforded the product 2(3.53g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 479.46.

(7) Synthesis of b-1-2

Compound b-1-2(4.79g, 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g, 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. Column chromatography on PE/EA afforded the product b-1-2(4.2g) as a black solid in 75.8% yield, which was determined by HPLC-MS (M +1) ═ 561.43. Elemental analysis: theoretical value C, 77.49; h, 5.30; n, 13.39; o, 3.82; measured value: c, 77.50; h, 5.30; n, 13.38; and O, 3.82.

Synthetic route to b-1-3

(1) Synthesis of b-1-3a

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol were added to compound a (2.63g 10mmol) and compound b tris-hydroxyphenylboronic acid (1.37g 10mmol) to react at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-3a (1.78g) as a white solid in 77.4% yield, which was measured by HPLC-MS (M +1) ═ 231.07.

(2) Synthesis of b-1-3b

Taking the compound b-1-3a (2.30g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. The product was isolated by PE/EA column chromatography in 80.3% yield from b-1-3b (1.83g) as a white solid and tested by HPLC-MS (M +1) ═ 229.05.

(3) Synthesis of b-1-3c

Compound b-1-3b (2.28g, 10mmol), di-tert-butyl dicarbonate (2.18g, 10mmol), triethylamine (5ml), and ethanol (100ml) were reacted at room temperature in a 250ml three-necked flask for 12 hours. Detecting the reaction progress by TLC, after the reaction is finished, filtering to remove salt, extracting by EA, washing for 5 times by saturated saline solution, and removing the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-3c (2.67g) as a white solid in 81.4% yield as measured by HPLC-MS (M +1) ═ 329.10.

(4) Synthesis of b-1-3d

Compound b-1-3c (3.28g 10mmol), 4-amino-3-iodobenzoyl chloride (2.8g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-3d (4.68 g) as a pale yellow solid in 81.7% yield and HPLC-MS (M +1) ═ 574.04.

(5) Synthesis of b-1-3e

The compound b-1-3d (5.73g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-3e (3.46g) as a pale yellow solid in 74.2% yield, and HPLC-MS (M +1) ═ 467.10.

(6) Synthesis of b-1-3

Compound b-3-6(4.67g, 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g, 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave product b-1-3 as a yellow solid (3.61g) in 88.7% yield as measured by HPLC-MS (M +1) ═ 407.14. Elemental analysis: theoretical value C, 73.88; h, 4.46; n, 13.78; o, 7.87; measured value: c, 73.88; h, 4.46; n, 13.78; and O, 7.87.

Synthetic route to b-1-4

(1) Synthesis of b-1-4a

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol were added to compound a (2.63g 10mmol) and compound b tris-hydroxyphenylboronic acid (1.37g 10mmol) to react at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-4a (1.48g) as a white solid in 81.1% yield as measured by HPLC-MS (M +1) ═ 231.22.

(2) Synthesis of b-1-4b

Taking the compound b-1-4a (2.31g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-4b (2.13g) as a grey solid in 68.5% yield, which was determined by HPLC-MS (M +1) ═ 229.22.

(3) Synthesis of b-1-4c

Taking the compound b-1-4b (2.30g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-4c (1.65g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 227.07.

(4) Synthesis of b-1-4d

Compound b-1-4c (2.27g 10mmol), 4-amino-3-iodobenzoyl chloride (2.8g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-4d (5.14g) as a pale yellow solid in 78.4% yield, and HPLC-MS (M +1) ═ 488.25.

(5) Synthesis of b-1-4e

The compound b-1-4d (4.88g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-4e (3.46g) as a grey solid in 54.8% yield, as determined by HPLC-MS (M +1) ═ 481.43.

(6) Synthesis of b-1-4f

Taking the compound b-1-4e (4.80g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-4f (3.78g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 495.46.

(7) b-1-4 Synthesis

Compound b-1-4f (4.941g, 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g, 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-44(3.97g) as a pale yellow solid in 91.2% yield, and HPLC-MS (M +1) ═ 435.49. Elemental analysis: theoretical value C, 74.64; h, 5.10; n, 12.89; o, 7.36; measured value: c, 74.65; h, 5.10; n, 12.89; and O, 7.36.

Synthetic route to b-1-5

(1) Synthesis of b-1-5a

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol were added to compound a (2.63g 10mmol) and compound b tris-hydroxyphenylboronic acid (1.37g 10mmol) to react at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-5a (1.72g) as a white solid in 74.4% yield as measured by HPLC-MS (M +1) ═ 231.07.

(2) Synthesis of b-1-5b

Taking the compound b-1-5a (2.30g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-5b (1.43g) as a white solid in 62.4% yield, which was measured by HPLC-MS (M +1) ═ 229.05.

(3) Synthesis of b-1-5c

Compound b-1-5b (2.29g, 10mmol), di-tert-butyl dicarbonate (2.18g, 10mmol), triethylamine (5ml), and ethanol (100ml) were reacted at room temperature in a 250ml three-necked flask for 12 hours. Detecting the reaction progress by TLC, after the reaction is finished, filtering to remove salt, extracting by EA, washing for 5 times by saturated saline solution, and removing the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-5c (2.65g) as a grey solid in 80.5% yield, which was determined by HPLC-MS (M +1) ═ 329.10.

(4) Synthesis of b-1-5d

The compound b-1-5c (3.29g 10mmol), 2-iodo-4-chloroaniline (2.52g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-5d (4.48g) as a yellow solid in 80.7% yield, which was measured by HPLC-MS (M +1) ═ 555.04.

(5) Synthesis of b-1-5e

The compound b-1-5d (5.55g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-5e (2.26g) as a yellow-green solid in 51.5% yield and HPLC-MS (M +1) ═ 439.10.

(6) Synthesis of b-1-5

Compound b-1-5e (4.39g, 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g, 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-5(2.87g) as a yellow solid in 72.6% yield as measured by HPLC-MS (M +1) ═ 395.15. Elemental analysis: theoretical value C, 76.17; h, 4.79; n, 14.81; o, 4.23; measured value: c, 76.18; h, 4.80; n, 14.80; and O, 4.22.

Synthetic route to b-1-6

(1) Synthesis of b-1-6a

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol were added to compound a (3.46g 10mmol) and compound b tris-hydroxyphenylboronic acid (1.37g 10mmol) to react at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-6a (1.48g) as a white solid in 81.1% yield as measured by HPLC-MS (M +1) ═ 231.22.

(2) Synthesis of b-1-6b

Taking the compound b-1-6a (2.31g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-6b (2.43g) as a grey solid in 81.3% yield as measured by HPLC-MS (M +1) ═ 229.20.

(3) Synthesis of b-1-6c

Taking the compound b-1-6b (2.29g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-6c (1.65g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 243.23.

(4) Synthesis of b-1-6d

Compound b-1-6c (2.43g 10mmol), 4-amino-3-iodochlorobenzene (2.8g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and dichloromethane (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-6d (3.80g) as a pale yellow solid in 82.3% yield, and HPLC-MS (M +1) ═ 460.24.

(5) Synthesis of b-1-6e

The compound b-1-6d (4.60g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-6e (1.57g) as a grey solid in 57.3% yield as measured by HPLC-MS (M +1) ═ 453.42.

(6) Synthesis of b-1-6f

Taking the compound b-1-6e (4.53g 10mmol) and methyl iodide (1.41g 10mmol) to be placed in a 250ml three-neck flask, and adding cuprous iodide (0.20g 1mmol), 1,10 phenanthroline (0.20g 1mmol) and potassium carbonate (0.7g 5mmol) to react for 12h at 140 ℃ under the nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-6f (3.17g) as a white solid in 73.0% yield, which was measured by HPLC-MS (M +1) ═ 467.44.

(7)b-1-6

Compound b-1-6f (4.67g, 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g, 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-6(3.15g) as a pale yellow solid in 77.5% yield, which was measured by HPLC-MS (M +1) ═ 406.43. Elemental analysis: theoretical value C, 76.75; h, 6.20; n, 13.26; o, 3.79; measured value: c, 76.73; h, 6.20; n, 13.28; o, 3.79.

Synthetic route to b-1-7

(1) Synthesis of b-1-7a

To a 250ml three-necked flask, potassium phosphate (1.07g 5mmol), palladium tetratriphenylphosphine (0.5g 0.5mmol), ethanol (120ml) and ethanol (1.56g 0.5mmol) were added to compound a (2.63g 10mmol) and compound b tris-chlorobenzeneboronic acid (1.56g 10mmol) to react at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-7a (1.56g) as a white solid in 62.7% yield, as determined by HPLC-MS (M +1) ═ 249.03.

(2) Synthesis of b-1-7b

Taking the compound b-1-7a (2.49g 10mmol) to a 100ml three-neck flask, adding hydrochloric acid (2ml) and hydrogen peroxide (5ml) and acetic acid (50ml) to react for 12h at 120 ℃. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Extract with EA, wash 5 times with saturated brine, and remove the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-7b (1.63g) as a white solid in 66.9% yield, which was measured by HPLC-MS (M +1) ═ 247.02.

(3) Synthesis of b-1-7c

Compound b-1-7b (2.47g, 10mmol), di-tert-butyl dicarbonate (2.18g, 10mmol), triethylamine (5ml), and ethanol (100ml) were reacted at room temperature in a 250ml three-necked flask for 12 hours. Detecting the reaction progress by TLC, after the reaction is finished, filtering to remove salt, extracting by EA, washing for 5 times by saturated saline solution, and removing the solvent by rotary evaporation. PE/EA column chromatography gave the product b-1-7c (2.25g) as a grey solid in 64.8% yield as measured by HPLC-MS (M +1) ═ 347.07.

(4) Synthesis of b-1-7d

The compound b-1-7c (3.47g 10mmol), 3-iodo-4-aminoaniline (2.34g 10mmol) was placed in a 250ml three-necked flask, and anhydrous aluminum chloride (0.65g 5mmol) and methylene chloride (80ml) were added thereto and reacted at 0 ℃ for 4 hours. The progress of the reaction was checked by TLC and after the reaction was complete, the temperature was slowly raised to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-7d (4.28g) as a yellow solid in 78.5% yield, which was determined by HPLC-MS (M +1) ═ 545.06.

(5) Synthesis of b-1-7e

The compound b1-7d (5.45g 10mmol), 4-nitrophenylboronic acid (1.67g 10mmol) were taken in a 250ml three-necked flask, and potassium phosphate (1.07g 5mmol), palladium tetrakistriphenylphosphine (0.5g 0.5mmol) and ethanol (120ml) were added thereto and reacted at 90 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. Filtering to remove salt, extracting with EA, washing with saturated saline solution for 5 times, removing solvent by rotary evaporation, adding dilute hydrochloric acid and ethanol, reacting for 2h, and removing solvent by rotary evaporation. The product was isolated by PE/EA column chromatography in the form of a yellow-green solid, b-1-7e (3.16g), in 72.1% yield and HPLC-MS (M +1) ═ 438.11.

(6) Synthesis of b-1-7

Compound b-1-7e (4.38g 10mmol) was placed in a 100ml three-necked flask, and tin dichloride (1.89g 50mmol) and ethanol (50ml) were added thereto and reacted at 70 ℃ for 12 hours under a nitrogen atmosphere. The progress of the reaction was checked by TLC and, after the reaction was complete, it was cooled to room temperature. The salt was removed by suction filtration, extracted with EA, washed 5 times with saturated brine and the solvent was removed by rotary evaporation. PE/EA column chromatography gave the product b-1-7(2.72g) as a yellow solid in 72.0% yield, which was measured by HPLC-MS (M +1) ═ 378.16. Elemental analysis: theoretical value C, 77.01; h, 5.72; n, 17.27; measured value: c, 77.00; h, 5.70; and N, 17.30.

Synthesis example A-1 of Polymer for alignment layer in alignment film

In a 500mL three-necked round-bottomed flask, under a nitrogen atmosphere, 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene (42.5g, 112 mmol) (hereinafter referred to as b-2-8), p-phenylenediamine (3.50g, 32.4 mmol) (hereinafter referred to as b-2-1), p-aminodiphenylethane (6.11g, 35.6 mmol) (hereinafter referred to as b-2-3) and 96.12g of NMP were placed, and the resulting suspension was stirred until a yellow solution was obtained. 38.54g (180 mmol) of 2,3, 5-tricarboxycyclopentylacetic dianhydride (hereinafter referred to as a-2) plus the molecular weight regulator n-hexylamine 0.40g (4mmol) and 96.12g of NMP were then added to the system. The reaction was allowed to exotherm and stirred at room temperature for 4 hours to give polyamic acid polymer A-1-1 having a solid content of 20% dissolved in NMP. Then, 400 mmol of acetic anhydride and 50mmol of pyridine were added at 60 ℃ and reacted at 60 ℃ for 3 hours, the resulting polyimide was poured into 2000 ml of deionized water, and the precipitate was collected and dried at room temperature to obtain 74.3 g of a product with a yield of 91%, and the number average molecular weight (Mn) as a result of confirming the molecular weight of polymer A-1-1 by GPC was 7550 g/mol.

Synthesis examples A-1-2 to A-1-20 were prepared by the same methods as in Synthesis example A-1-1, except that: the kind and amount of the monomers used were varied, and the specific results are shown in Table 1 below, which are not repeated herein. Synthesis of Polymer B-1-1 of the conductive layer of the alignment agent

In a 500mL three-necked round-bottomed flask, pyromellitic dianhydride (21.82g, 100 mmol) (hereinafter referred to as a-3), diamine b-1-1, 8.12g (20mmol), diamine b-1-2, 16.81g (30mmol), 3, 5-diaminobenzoic acid (3.85, 25 mmol) (hereinafter referred to as b-2-1), N, N' -bis (4-aminophenyl) piperazine (6.55g, 25 mmol) (hereinafter referred to as b-2-5) were charged under nitrogen atmosphere, and the resulting suspension was stirred until a yellow solution was obtained. The reaction was allowed to exotherm and stirred at room temperature for 4 hours to give polyamic acid polymer B-1-1 having a solid content of 20% dissolved in NMP. As a result of confirming the molecular weight of the polymer B-1-1 by GPC, the number average molecular weight (Mn) was 36500 g/mol.

Synthesis examples B-1-2 to B-1-20 were prepared by the same methods as in Synthesis example B-1-1, except that: the kind and amount of the monomers used were varied, and the specific results are shown in Table 2 below, which are not repeated herein. As comparative examples, A-1-1 to A-1-10 can be selected, but B-1 of the conductive layer is not added.

In tables 1 and 2:

a-1: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride

a-2: 2,3, 5-tricarboxylic cyclopentyl acetic dianhydride

a-3: pyromellitic dianhydride

a-4: 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride

b-2-1: p-phenylenediamine

b-2-2: 1, 2-bis (4-aminophenoxy) ethane

b-2-3: 3, 5-diaminobenzoic acid methyl ester

b-2-4: 3, 5-diaminobenzoic acid

b-2-5N, N' -bis (4-aminophenyl) piperazine

b-2-6: 4, 4' -diaminobenzamides

b-2-7: 4, 4' -diaminodiphenylethane

b-2-8: 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene

b-2-9: 4- (4-heptylcyclohexyl) phenyl-3, 5-diaminobenzoate

Table 1: the type and amount of monomers used for synthesizing the polymer of the orientation layer

TABLE 2 kinds and amounts of monomers used for polymers of conductive layer of alignment film

Liquid crystal aligning agent C-1

50 parts by weight of polymer (A-1-1), 50 parts by weight of polymer (B-1-1), 150 parts by weight of NMP and 200 parts by weight of ethylene glycol monobutyl ether were charged into a three-necked round-bottomed flask under nitrogen protection, the system was stirred at room temperature for 60 minutes, and then the solution was filtered through a 0.2 μm filter to obtain liquid crystal aligning agent C-1-1 of example 1.

The liquid crystal aligning agents C-1-2 to C-1-20 were prepared in the same manner as in the liquid crystal aligning agent C-1-1 of comparative examples C-2-1 to C-2-10 except that the kinds and amounts of the polymer (A) and the solvent (B) used were changed, and they will not be described in detail herein.

In Table 3

B-1: n-methyl-2-pyrrolidone

B-2: ethylene glycol monobutyl ether

TABLE 3 composition of liquid crystal aligning agent

Liquid crystal alignment film and liquid crystal display element

The liquid crystal aligning agent of example 1 was coated on a first glass substrate having an ITO electrode by means of roll coating to form a precoat layer. Pre-curing (hot plate, 85 ℃,10 minutes), main curing (circulating oven, 225 ℃, 50 minutes), exposing (254nm polarized light, 5 mW/cm)²、1000mj/cm²) A first glass substrate having an ITO electrode on which the liquid crystal alignment film of example 1 was formed was obtained.

The liquid crystal aligning agent of example 1 was coated on a second glass substrate having no ITO electrode by means of roll coating to form a precoat layer. The second glass substrate on which the liquid crystal alignment film of example 1 was formed was also obtained after the above-described precuring, main curing, and exposure to light.

An ultraviolet curing adhesive was coated on the periphery of one of the first glass substrate and the second glass substrate, and a spacer of 3.5 μm was sprinkled on the other substrate. Then, the two glass substrates were bonded in a manner antiparallel to the orientation direction (5kg, 30min), and then irradiated with an ultraviolet lamp to cure the ultraviolet-curable adhesive. Then, the liquid crystal is injected, the injection port of the liquid crystal is sealed by using ultraviolet curing glue, the ultraviolet curing glue is cured by using ultraviolet light, and then polarizing plates are respectively attached to the outer sides of the two glass substrates, so that the IPS mode liquid crystal display element of embodiment 1 can be obtained.

[ evaluation of reliability of Voltage Holding Ratio (VHR) ]

Polarizers are attached to the upper and lower plates of the liquid crystal cell such that their polarization axes are perpendicular to each other. The liquid crystal cell was adhered to 7000cd/m²Using PR755, the luminance in the black mode was measured. The liquid crystal cell was then driven at 5V AC voltage for 24 hours at room temperature. Thereafter, the luminance in the black mode is measured in the same manner as described above in a state where the voltage of the liquid crystal cell is turned off. To be used in driving liquid crystal cellsThe difference between the previously measured incident luminance (L0) and the luminance after driving the liquid crystal cell (L1) is divided by the initial luminance (L0) and multiplied by 100 to characterize the change in luminance. The smaller this value, the more excellent the surface orientation stability. The level of AC afterimage was evaluated by measuring the variation value of the luminance according to the following criteria. In the measurement results, if the variation value is less than 5%, it is evaluated as "excellent"; if the brightness change value is 5% -10%, the evaluation is 'good'; the evaluation is 'normal' if the variation value is 10% -20%; if the luminance change value is greater than 20%, it is evaluated as "poor".

The voltage holding ratio and AC afterimage evaluation results are shown in table 4 below:

example No	Orientation agent	Voltage holding ratio (%)	AC afterimage
				1	C-1-1	99.2	Superior food
2	C-1-2	98.9	Superior food
				3	C-1-3	98.8	Superior food
4	C-1-4	99.4	Superior food
				5	C-1-5	98.7	Superior food
6	C-1-6	98.9	Superior food
				7	C-1-7	99.3	Superior food
8	C-1-8	98.7	Superior food
				9	C-1-9	98.6	Superior food
10	C-1-10	99.0	Superior food
				11	C-1-11	99.1	Superior food
12	C-1-12	98.6	Superior food
				13	C-1-13	99.3	Superior food
14	C-1-14	99.0	Superior food
				15	C-1-15	98.9	Superior food
16	C-1-16	99.4	Superior food
				17	C-1-17	99.2	Superior food
18	C-1-18	98.9	Superior food
				19	C-1-19	98.7	Superior food
20	C-1-20	98.9	Superior food
				21	C-2-1	60.2	Difference (D)
22	C-2-2	58.4	Difference (D)
				23	C-2-3	55.0	Difference (D)
24	C-2-4	56.4	Difference (D)
				25	C-2-5	55.3	Difference (D)
26	C-2-6	55.7	Difference (D)
				27	C-2-7	56.6	Difference (D)
28	C-2-8	40.6	Difference (D)
				29	C-2-9	58.6	Difference (D)
30	C-2-10	54.2	Difference (D)

Evaluation of Long-term Heat resistance (minute Brightness failure)

The test results are shown in table 5:

example No	Orientation agent	Long term heat resistance (micro-bright point failure)
			1	C-1-1	Good effect
2	C-1-2	Good effect
			3	C-1-3	Good effect
4	C-1-4	Good effect
			5	C-1-5	Good effect
6	C-1-6	Good effect
			7	C-1-7	Good effect
8	C-1-8	Good effect
			9	C-1-9	Good effect
10	C-1-10	Good effect
			11	C-1-11	Good effect
12	C-1-12	Good effect
			13	C-1-13	Good effect
14	C-1-14	Good effect
			15	C-1-15	Good effect
16	C-1-16	Good effect
			17	C-1-17	Good effect
18	C-1-18	Good effect
			19	C-1-19	Good effect
20	C-1-20	Good effect

Evaluation of AC afterimage characteristics and contrast characteristics (evaluation of liquid Crystal alignment)

As can be seen from the data in table 5, compared with the prior art, the liquid crystal aligning agent of the present invention is prepared by polymerizing a diamine monomer containing a stable carbazole structure with other tetracarboxylic dianhydride monomers; because the diamine monomer contains a carbazole structure with a stable structure, the residual charge of the polymerized material disappears quickly, and the thermal stability is outstanding. Therefore, the liquid crystal alignment film of the present invention has stable Voltage Holding Ratio (VHR) under temperature change conditions by using a diamine monomer having a carbazole structure stabilized by a monomer structure; the carbazole structural segment with larger polarity enables residual charges in the liquid crystal box to be rapidly released, so that the prepared liquid crystal box has the advantages of small difference between high and low voltage holding rates and rapid residual charge disappearance, and the display effect of the liquid crystal display can be improved. And the method is simple, has wide market prospect and is suitable for large-scale application and popularization.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A liquid crystal alignment film material comprising a polymer a and a solvent B obtained by reacting a mixture, wherein the mixture comprises a tetracarboxylic dianhydride component a and a diamine component B, the diamine component B comprises at least a diamine compound B-1 represented by formula 1, and the diamine compound B-1 has the following structural formula:

x in formula 1: -O-, -CO-, -S-, -O-CO-, -NH-CO-, -O- (CH)₂) m- (m is independently an integer of 1 to 12),

R is methyl or hydrogen.

2. The liquid crystal alignment film material of claim 1, wherein the polymer A is one or a mixture of two of polyamic acid and polyimide.

3. The liquid crystal alignment film material according to claim 1, characterized in that: comprises a polymer A obtained by reacting a mixture and a solvent B, wherein the polymer A comprises a tetracarboxylic dianhydride component a and a diamine component B; the tetracarboxylic dianhydride component a is one or more of 1,2,3, 4-cyclobutane tetracarboxylic dianhydride, pyromellitic dianhydride, 2,3, 5-tricarboxycyclopentyl acetic dianhydride and 3,3 ', 4, 4' -biphenyl tetracarboxylic dianhydride;

4. A liquid crystal aligning agent characterized in that: comprising a conductive layer polymer selected from the liquid crystal alignment film materials according to any one of claims 1 to 3 and an alignment layer polymer selected from the imidized polyimides synthesized from tetracarboxylic dianhydride component a and diamine component b in a molar ratio of 100: (10-150), wherein the molar percentage of the strong polar diamine compound b-1 in the diamine component b is 20-60%.

5. The liquid crystal aligning agent according to claim 4, wherein: the diamine component b in the alignment layer polymer also comprises a long side chain diamine, the long side chain diamine is 1- (4- (4-heptylcyclohexyl) phenoxy) -2, 4-diaminobenzene, and the mole percentage of the long side chain diamine in the diamine component b is 40-90%.

6. The liquid crystal aligning agent according to claim 5, wherein: the mole percentage of the long side chain diamine in the diamine component b is 50-70%.

7. A liquid crystal alignment film, characterized by using the liquid crystal aligning agent according to any one of claims 4 to 6.

8. The liquid crystal alignment film according to claim 7, wherein: the conductive layer polymer used in the conductive layer has a number average molecular weight Mn of 25000-45000 g/mol, and the alignment layer polymer used in the alignment layer has a number average molecular weight Mn of 7500-15000 g/mol.

9. A method for producing a liquid crystal alignment film according to claim 7 or 8, characterized in that: the method comprises the following steps:

10. A liquid crystal display element comprising the liquid crystal alignment film according to claim 7 or 8.