An epoxy group-containing compound and its application

Abstract

The present invention discloses an epoxy group-containing compound and its application. The present invention has obtained an epoxy group-containing compound with a special structure and introduced it into a liquid crystal aligning agent. The prepared liquid crystal alignment film has improved rubbing resistance, and at the same time, the prepared liquid crystal display element has an improved voltage holding ratio (VHR), a reduced amount of direct current (DC) charge accumulation, and an improved long-term reliability.

Description

Technical Field

[0001] The present application relates to a compound containing an epoxy group, a liquid crystal aligning agent, and also to their preparation methods and applications, belonging to the technical field of liquid crystal alignment materials. Background Art

[0002] In recent years, research has been continuously carried out on improving display quality such as high fineness of liquid crystal display elements and reducing power consumption, and the scope of use of liquid crystal display elements has also been continuously expanding. As a result, there is a demand for a liquid crystal display element with higher display quality and whose display quality does not deteriorate even during long-term continuous driving. However, in a liquid crystal display element having a liquid crystal alignment film formed of polyamic acid or polyimide, it has been pointed out that during long-term continuous driving, the liquid crystal alignment film deteriorates due to heat or light, resulting in deterioration problems such as a decrease in display quality; in addition, if charges accumulate in the liquid crystal alignment film, even short-term driving is likely to cause afterimages, and these accumulated charges will affect the display in the form of liquid crystal alignment disorder and afterimages, significantly reducing the display quality of the liquid crystal element. Therefore, there is a strong demand for a liquid crystal alignment film with less accumulation of direct current charges (DC), fast release, and high long-term reliability.

[0003] Patent WO2019 / 078502 discloses a specific liquid crystal alignment film with good alignment and high film strength, and exhibits excellent durability; as a method for shortening the afterimage disappearance time, Patent WO2018 / 030489 proposes an alignment film prepared using a polymer containing a specific structure, and further, the liquid crystal display element can obtain characteristics of a high voltage holding ratio and fast relaxation of accumulated charges. However, with the high performance of liquid crystal display elements, the required performance of liquid crystal alignment films has become more stringent, and what is more needed is a liquid crystal alignment film with balanced performance in all aspects. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the present application provides a compound containing an epoxy group, which can be used in a liquid crystal aligning agent and can improve the optoelectronic properties, mechanical strength, and stability of the liquid crystal alignment film.

[0005] In a first aspect, the present application provides a compound containing an epoxy group, and the compound has a structural formula represented by formula (1):

[0006]

[0007] In the above formula (1), the group represented by R is selected from H, alkyl, haloalkyl, cyclohexyl, phenyl, and biphenyl.

[0008] In another aspect, the present application provides a liquid crystal aligning agent, and the liquid crystal aligning agent includes polymer A and a compound B containing an epoxy group.

[0009] Furthermore, the polymer A is at least one of polyamic acid and polyimide.

[0010] Furthermore, the epoxy group-containing compound B is at least one of the epoxy group-containing compounds represented by the above general formula (1).

[0011] Furthermore, the liquid crystal aligning agent further includes a solvent C. Among them, the solvent C is an organic solvent.

[0012] On the other hand, the present application provides a liquid crystal alignment film, which is prepared from the above liquid crystal aligning agent.

[0013] On the other hand, the present application provides a liquid crystal display element, which includes the above liquid crystal alignment film.

[0014] The present invention has the following beneficial effects:

[0015] 1. The epoxy groups contained in the present invention can open the ring and generate cross-linking during the curing process of the alignment film, thereby enhancing the chemical stability and mechanical strength of the cured film; and introducing rigid groups such as naphthalene rings into the epoxy group-containing compounds can improve the alignment uniformity of liquid crystals. Therefore, by utilizing the synergistic effect of the two, the epoxy group-containing compound of the present invention is used in the liquid crystal aligning agent, which can improve the optoelectronic properties, mechanical strength and stability of the liquid crystal alignment film.

[0016] 2. The present invention introduces an epoxy group-containing compound with a special structure into the liquid crystal aligning agent, improves the optoelectronic properties, mechanical strength and stability of the liquid crystal alignment film, makes the voltage holding ratio (VHR) of the liquid crystal display element containing the liquid crystal alignment film increase, the friction resistance increase, the long-term reliability increase, the liquid crystal alignment excellent, and the direct current charge (DC) release fast and the direct current charge (DC) accumulation reduced, and the overall performance is improved. Specific Embodiments

[0017] The following provides a more detailed explanation and description of the present invention so that those skilled in the art can have a deeper understanding of the advantages of the technical solution of the present invention. It should be understood that the following description is only exemplary and does not limit its content.

[0018] The present application provides an epoxy group-containing compound, which has a structural formula represented by formula (1):

[0019]

[0020] In the above formula (1), the group represented by R is selected from H, alkyl, haloalkyl, cyclohexyl, phenyl, and biphenyl.

[0021] Further, the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and the alkyl group having 1 to 5 carbon atoms may be a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, etc.

[0022] Further, the haloalkyl group is preferably a haloalkyl group having 1 to 5 carbon atoms, and the haloalkyl group having 1 to 5 carbon atoms may be a trifluoromethyl group, a trifluoroethyl group, etc.

[0023] Further, the compound of the present invention contains structures such as an epoxy group and a naphthyl group. When the compound containing an epoxy group is added to a liquid crystal aligning agent and then in the process of curing to form a liquid crystal alignment film, the epoxy group undergoes a ring-opening reaction and generates crosslinking, which can improve the surface denseness of the liquid crystal alignment film and further improve the rubbing resistance of the liquid crystal alignment film. At the same time, the compound containing an epoxy group itself has rigid groups such as a naphthalene ring, which can further improve the alignment uniformity of the liquid crystal alignment film, so that the overall performance of the entire liquid crystal alignment film is improved, and the reliability and stability are higher.

[0024] Further, in the compound containing an epoxy group, the stronger the rigidity of the R group, the more uniform the orientation and the higher the hardness of the obtained liquid crystal alignment film. If the stability of the R group is stronger, the transmittance of the obtained liquid crystal alignment film is higher and the electrical properties are better. From the perspective of the balanced performance of the liquid crystal alignment film, the R group is preferably an alkyl group having 1 to 5 carbon atoms, a haloalkyl group having 1 to 5 carbon atoms, a cyclohexyl group or a biphenyl group, and more preferably CH2CH3, CF3, a cyclohexyl group or a biphenyl group.

[0025] Further, the compound containing an epoxy group of the present invention is preferably any one of the compounds having the structures shown in the following formulas (B-1) to (B-4):

[0026]

[0027]

[0028] On the other hand, the present application provides a method for preparing the above-mentioned compound containing an epoxy group, and the reaction formula when R is hydrogen is:

[0029]

[0030] Among them, the reaction formula when R is an alkyl group, a haloalkyl group, a cyclohexyl group, a phenyl group or a biphenyl group is:

[0031]

[0032] On the other hand, the present application provides a liquid crystal aligning agent, and the liquid crystal aligning agent includes a polymer A. The polymer A is at least one of polyamic acid and polyimide.

[0033] Further, the polyamic acid and polyimide can be selected from polyimides or polyamic acids that are publicly available in the prior art and can be used in liquid crystal aligning agents, or can be prepared by oneself. The polyamic acid can be obtained by reacting a tetracarboxylic dianhydride compound CA with a diamine compound DA, and the polyimide can be obtained by dehydrating and cyclizing the polyamic acid.

[0034] Further, the tetracarboxylic dianhydride compound CA includes at least one of an aliphatic tetracarboxylic dianhydride and an aromatic tetracarboxylic dianhydride. These tetracarboxylic dianhydride compounds can be used alone or in combination of two or more.

[0035] Preferably, the aliphatic tetracarboxylic dianhydride is selected from at least one of cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 1,2,3,4-cyclohexane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,4-dicarboxy-1-cyclohexyl succinic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic anhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, etc.

[0036] Preferably, the aromatic tetracarboxylic dianhydride is selected from at least one of pyromellitic dianhydride, 3,3,4,4'-biphenyltetracarboxylic dianhydride, 2,2,3,3'-biphenyltetracarboxylic dianhydride, 2,3,3,4'-biphenyltetracarboxylic dianhydride, 3,3,4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3,4'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl) ether dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4'-(4,4'-isopropyl diphenoxy) diphthalic anhydride, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, 4,4'-isopropylidene-bis(phthalic anhydride), etc.

[0037] Further, examples of the diamine compound DA include aliphatic diamines, alicyclic diamines, aromatic diamines, and other diamines. Similarly, these diamine compounds can be used alone or in combination of two or more.

[0038] Preferably, examples of the aliphatic diamine include at least one of m-xylylenediamine, 1,3-propanediamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, etc.

[0039] Preferably, examples of the alicyclic diamine include at least one of 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(aminomethyl)cyclohexane, and the like.

[0040] Preferably, examples of the aromatic diamine include at least one of p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-thiodianiline, 3,3'-thiodianiline, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 2,2'-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, and the like.

[0041] Preferably, examples of the other diamine include compounds having the following formula DA-1 and formula DA-2:

[0042]

[0043] Method for producing polyamic acid:

[0044] The polyamic acid of the present invention can be prepared by the methods disclosed in the prior art. For example, the method for preparing the polyamic acid may include the following steps: dissolving a tetracarboxylic dianhydride compound CA and a diamine compound DA in a solvent, and carrying out a polymerization reaction at -20°C to 150°C, more preferably at 0 to 100°C, preferably for 0.1 to 24 hours, more preferably for 0.5 to 12 hours.

[0045] Furthermore, the solvent used for the polymerization reaction of the tetracarboxylic dianhydride compound CA and the diamine compound DA can be the same as or different from the solvent in the liquid crystal aligning agent, and there is no particular limitation on the solvent in the polymerization reaction as long as it can dissolve the reactants and products. Preferably, the solvent includes but is not limited to at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-methylcaprolactam, N-methyl-2-pyrrolidone, γ-butyrolactone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol methyl ethyl ether, ethylene glycol dimethyl ether, dimethyl sulfoxide, etc. These solvents can be used alone or in combination. In addition, since water inhibits the polymerization reaction and causes hydrolysis of the resulting polyamic acid, a dehydrated and dried solvent is preferably used. From the perspective of difficult precipitation of the polymer and easy obtaining of high molecular weight, based on the total usage amount of the tetracarboxylic dianhydride compound CA and the diamine compound DA being 100 parts by weight, the usage amount of the solvent for the polymerization reaction is 200 - 2000 parts by weight, such as 200 parts by weight, 500 parts by weight, 1000 parts by weight, 1500 parts by weight, 1800 parts by weight, 2000 parts by weight; more preferably, the usage amount of the solvent for the polymerization reaction is 500 parts by weight to 1800 parts by weight.

[0046] As described above, after the polymerization reaction is completed, a reaction solution containing the polyamic acid is obtained. This reaction solution can be directly supplied for the preparation of the liquid crystal aligning agent, or the polyamic acid contained in the reaction solution can be separated and then supplied for the preparation of the liquid crystal aligning agent, or the separated polyamic acid can be refined and then supplied for the preparation of the liquid crystal aligning agent.

[0047] The separation and purification of polyamic acid can be carried out by injecting a poor solvent while sufficiently stirring the obtained polyamic acid solution to precipitate the polymer, and then recovering the polymer by filtration. The polymer recovered by filtration is dissolved in a solvent again, and the operations of reprecipitation and filtration recovery are repeated. By repeating this process multiple times, the impurities in the polymer can be reduced. Then, drying at room temperature or heating drying can be carried out to obtain a purified polyamic acid solid. There is no particular limitation on the poor solvent, and it can be alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. Specific examples of such poor solvents can include at least one of methanol, ethanol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, etc.

[0048] Method for manufacturing polyimide:

[0049] Polyimide can be manufactured by imidizing polyamic acid. It can be synthesized by dehydrating and cyclizing (imidizing) the polyamic acid as described above. The dehydration and cyclization of polyamic acid can be carried out by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a basic catalyst to the solution, and heating as required. Chemical imidization can carry out the imidization reaction at a relatively low temperature, and it is not easy to cause a decrease in the molecular weight of the polymer during the imidization process, so it is preferred.

[0050] Chemical imidization can be carried out as follows: Add a dehydrating agent and a basic catalyst to the polyamic acid solution. As the dehydrating agent, acid anhydrides such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride, etc. can be used. Among them, when using acetic anhydride, it is relatively easy to purify at the end of the reaction, so it is preferred. In addition, as the basic catalyst, tertiary amines such as pyridine, collidine, dimethylpyridine, triethylamine, etc. can be used, but it is not limited to these. As the organic solvent used in the dehydration and cyclization reaction, the solvents used in the synthesis of polyamic acid can be listed.

[0051] The temperature for the imidization reaction is from -20°C to 140°C, such as -20°C, -10°C, 0°C, 20°C, 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, and preferably from 0°C to 100°C. The reaction time can be carried out within 1 to 100 h, such as 1 h, 5 h, 10 h, 30 h, 50 h, 80 h, 100 h. The amount of the imidization basic catalyst is 0.5 to 30 molar times that of the polyamic acid group, such as 0.5 molar times, 1 molar times, 5 molar times, 10 molar times, 15 molar times, 20 molar times, 25 molar times, 30 molar times, and preferably 2 to 20 molar times. The amount of the dehydrating agent is 1 to 50 molar times that of the polyamic acid group, such as 1 molar times, 5 molar times, 10 molar times, 15 molar times, 20 molar times, 25 molar times, 30 molar times, 35 molar times, 40 molar times, 45 molar times, 50 molar times, and preferably 3 to 30 molar times. The imidization rate of the obtained polymer does not necessarily have to reach 100%, and can be controlled by adjusting the amount of catalyst, temperature, reaction time, etc.

[0052] The polyimide solution obtained after the imidization reaction contains the added catalyst, etc. remaining therein. Therefore, it is preferable to recover the obtained polyimide polymer by the following means, redissolve it with an organic solvent, and supply it for the preparation of the liquid crystal aligning agent.

[0053] For the solution of the polyimide obtained above, it can be put into a poor solvent, so that the polymer can precipitate out. The polymer can be recovered by filtration, and the precipitated recovered polymer is redissolved in a solvent and subjected to the operation of reprecipitation recovery. Repeating this process multiple times can reduce the impurities in the polymer, and then drying at normal temperature or heating can obtain a purified polymer solid.

[0054] The poor solvent mentioned is the same as the poor solvent mentioned in the manufacturing method of the polyamic acid.

[0055] For the molecular weight of the polyimide or polyamic acid used in the liquid crystal aligning agent of the present invention, in terms of the weight average molecular weight (Mw), it is preferably 2000 to 500000, such as 2000, 5000, 10000, 50000, 100000, 150000, 200000, 250000, 300000, 350000, 400000, 450000, 500000, more preferably 5000 to 300000, and still more preferably 10000 to 100000.

[0056] The solution viscosities of the polyamic acid and the polyimide:

[0057] The polyamic acid and polyimide polymers used in the present invention preferably have a solution viscosity of 10 to 500 mPa·s, such as 10 mPa·s, 20 mPa·s, 50 mPa·s, 100 mPa·s, 300 mPa·s, 500 mPa·s, when respectively formulated into solutions with a concentration of 6 wt%, and more preferably have a solution viscosity of 20 to 300 mPa·s.

[0058] The solution viscosity (mPa·s) of the above polymers is tested as follows: The polymer is formulated into a polymer solution with a concentration of 6 wt% using a good solvent for the polymer (such as N-methyl-2-pyrrolidone, γ-butyrolactone, etc.), and then the viscosity value of the solution is measured with an E-type rotational viscometer at 25°C.

[0059] Furthermore, the liquid crystal aligning agent further includes a compound B containing an epoxy group, and the compound B containing an epoxy group is at least one of the compounds containing an epoxy group represented by the above general formula (1).

[0060] Furthermore, the liquid crystal aligning agent further includes a solvent C. Among them, the solvent C is an organic solvent, and the solvent C is preferably at least one of N-methylpyrrolidone, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, N,N-dimethylformamide, N,N-dimethylacetamide, butyl cellosolve, etc.

[0061] Furthermore, based on 100 parts by weight of the amount of the polymer A used, the amount of the compound B containing an epoxy group used is 0.5 to 20 parts by weight, such as 0.5 part, 1 part, 1.5 parts, 2 parts, 5 parts, 10 parts, 15 parts, 20 parts, preferably 1 to 20 parts, and more preferably 1 to 10 parts. When the content of the compound containing an epoxy group is too low, there will be disadvantages such as low hardness, poor abrasion resistance, low voltage holding ratio, and poor reliability.

[0062] Further, based on 100 parts by weight of the polymer A, the amount of the solvent C used is 500 to 5000 parts by weight, such as 500 parts, 1000 parts, 1500 parts, 2000 parts, 2500 parts, 3000 parts, 3500 parts, 4000 parts, 4500 parts, 5000 parts, preferably 1000 to 3000 parts, and more preferably 1000 to 2000 parts. Within this dosage range, the liquid crystal aligning agent has good printability.

[0063] Furthermore, the preparation of the liquid crystal aligning agent of the present invention is simple, and it can be obtained by uniformly mixing each component.

[0064] On the other hand, the present application provides a liquid crystal alignment film, which is prepared from the above-mentioned liquid crystal aligning agent.

[0065] Preparation method of the liquid crystal alignment film:

[0066] The liquid crystal alignment film of the present invention can be obtained by coating the liquid crystal aligning agent of the present invention on a substrate, and then performing operations such as baking and alignment.

[0067] As the substrate for coating the liquid crystal aligning agent of the present invention, as long as it is a substrate with high transparency, there are no other special limitations. Glass substrates, acrylic substrates, silicon nitride substrates, polycarbonate substrates, polyurethane substrates, trimethylpentene substrates, cellulose triacetate substrates, cellulose acetate butyrate substrates, etc. can be used. In addition, from the perspective of simplifying the process, it is preferable to use a substrate with an ITO electrode for driving liquid crystals, etc. In addition, in a reflective liquid crystal display element, if only one-sided substrate is used, an opaque material such as a silicon wafer can be used, and in this case, an electrode that reflects light, such as aluminum, can also be used.

[0068] As the coating method of the liquid crystal aligning agent of the present invention, printing methods such as screen printing, offset printing, and flexographic printing can be cited, as well as spraying methods, spin coating methods, inkjet methods, etc. From the aspect of production efficiency, the printing method is often used in industrial production and can also be appropriately used in the present invention.

[0069] After coating the liquid crystal aligning agent by the above coating method, the formed coating film is baked to form a cured film. The drying process after coating the liquid crystal aligning agent is not essential, and the time from coating to baking for each substrate is not fixed. This drying only needs to remove the solvent until the shape of the coating film will not be deformed due to the handling of the substrate, etc., and there is no particular limitation on the drying means. For example, it can be cited to dry at 50 - 120°C, preferably 60 - 100°C for 1 minute - 10 minutes, preferably 2 - 5 minutes, and then bake and cure at 150 - 300°C, preferably 200 - 240°C for 5 - 120 minutes, preferably 10 - 30 minutes. The thickness of the cured thin film is not particularly limited. When the thin film thickness is too thin, the reliability of the liquid crystal display element may be reduced, so it is 5 - 300 nm, preferably 10 - 200 nm.

[0070] As a method for performing an alignment treatment on the thin film, a rubbing method, a photo-alignment treatment method, etc. can be cited. The liquid crystal aligning agent of the present invention has better effects when used in the rubbing alignment treatment method.

[0071] On the other hand, the present application provides a liquid crystal display element, and the liquid crystal display element includes the above liquid crystal alignment film.

[0072] Manufacturing method of the liquid crystal display element:

[0073] Regarding the liquid crystal display element of the present invention, after obtaining a substrate with a liquid crystal alignment film obtained from the above liquid crystal aligning agent, a liquid crystal cell is manufactured by a known method, and the element is made using this liquid crystal cell.

[0074] Specific manufacturing methods of the liquid crystal display element are listed as follows: First, prepare a pair of substrates with a liquid crystal alignment film. Then, scatter spacers on the liquid crystal alignment film of a single substrate, and stick it to another substrate with the liquid crystal alignment film surface as the inner side, inject liquid crystal under reduced pressure and seal. Or, after dripping liquid crystal onto the liquid crystal alignment film surface where spacers are scattered, stick the substrates and seal. The thickness of the spacers at this time is preferably 1 - 30 μm, more preferably 2 - 10 μm.

[0075] The following further elaborates on the present invention in combination with specific embodiments, but the present invention is not limited to the following embodiments. The methods are all conventional methods unless otherwise specified. The materials can all be obtained from public commercial channels unless otherwise specified.

[0076] The molecular weights of the polyimide and polyamic acid obtained in the following examples were all determined by the GPC method (Shimadzu Corporation, Japan, gel permeation chromatography), the mobile phase was N-methylpyrrolidone, and the obtained molecular weights were all weight-average molecular weights (Mw).

[0077] The abbreviations of the components used in the following synthesis examples and examples are as follows:

[0078] NMP: N-methyl-2-pyrrolidone;

[0079] BC: butyl cellosolve;

[0080] Diamine compound DA:

[0081]

[0082] Tetracarboxylic dianhydride compound CA:

[0083]

[0084]

[0085] Compound containing epoxy group:

[0086]

[0087]

[0088] Synthesis Example 1

[0089] N₂ was introduced into a 500 mL four-necked flask equipped with a stirring device. 3.0 g (0.013 mol) of DA-1, 11.21 g (0.053 mol) of DA-3, and 172.21 g of NMP were added in sequence. After dissolution, 29.71 g (0.033 mol) of CA-2 and 36.47 g (0.033 mol) of CA-3 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-1. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 68045 g / mol as measured by GPC.

[0090] Synthesis Example 2

[0091] N₂ was introduced into a 500 mL four-necked flask equipped with a stirring device. 3.0 g (0.013 mol) of DA-1, 10.57 g (0.053 mol) of DA-4, and 173.85 g of NMP were added in sequence. After dissolution, 17.40 g (0.033 mol) of CA-1 and 29.71 g (0.033 mol) of CA-2 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-2. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 66315 g / mol as measured by GPC.

[0092] Synthesis Example 3

[0093] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 3.0 g (0.013 mol) of DA-1, 10.57 g (0.053 mol) of DA-4, and 168.61 g of NMP were added in sequence. After dissolution, 29.71 g (0.033 mol) of CA-2 and 36.47 g (0.033 mol) of CA-3 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-3. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 67663 g / mol as measured by GPC.

[0094] Synthesis Example 4

[0095] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 5.0 g (0.012 mol) of DA-2, 10.05 g (0.047 mol) of DA-3, and 167.49 g of NMP were added in sequence. After dissolution, 28.70 g (0.030 mol) of CA-2 and 35.80 g (0.030 mol) of CA-3 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-4. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 67378 g / mol as measured by GPC.

[0096] Synthesis Example 5

[0097] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 5.0 g (0.012 mol) of DA-2, 9.48 g (0.047 mol) of DA-4, and 168.96 g of NMP were added in sequence. After dissolution, 16.63 g (0.030 mol) of CA-1 and 28.70 g (0.030 mol) of CA-2 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-5. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 68815 g / mol as measured by GPC.

[0098] Synthesis Example 6

[0099] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 5.0 g (0.012 mol) of DA-2, 9.48 g (0.047 mol) of DA-4, and 164.28 g of NMP were added in sequence. After dissolution, 28.70 g (0.030 mol) of CA-2 and 35.80 g (0.030 mol) of CA-3 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-6. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 67967 g / mol as measured by GPC.

[0100] Synthesis Example 7

[0101] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 3.0 g (0.013 mol) of DA-1, 11.21 g (0.053 mol) of DA-3, and 177.46 g of NMP were added in sequence. After dissolution, 17.40 g (0.033 mol) of CA-1 and 29.71 g (0.033 mol) of CA-2 were added. After reacting at room temperature for 24 hours, 15.66 g (0.198 mol) of pyridine and 33.67 g (0.33 mol) of acetic anhydride were added in sequence, and the imidization reaction was carried out at 50 °C for 5 hours. Then the reaction solution was poured into ethanol for precipitation, filtered by suction to obtain a white powdery solid. The obtained white solid was washed with ethanol, then dissolved in NMP, and then precipitated in ethanol again, and filtered by suction to refine the polyimide. Finally, the refined polyimide was dried under vacuum for standby. The polyimide solid after vacuum drying was first dissolved in NMP, and then BC was added to prepare a polyimide solution PI-1. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 66876 g / mol as measured by GPC.

[0102] Synthesis Example 8

[0103] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 5.0 g (0.012 mol) of DA-2, 10.05 g (0.047 mol) of DA-3, and 172.19 g of NMP were added in sequence. After dissolution, 16.63 g (0.030 mol) of CA-1 and 8.70 g (0.030 mol) of CA-2 were added. After reacting at room temperature for 24 hours, 14.00 g (0.177 mol) of pyridine and 30.12 g (0.295 mol) of acetic anhydride were added in sequence, and the imidization reaction was carried out at 50 °C for 5 hours. Then the reaction solution was poured into ethanol for precipitation, filtered by suction to obtain a white powdery solid. The obtained white solid was washed with ethanol, then the white solid was dissolved in NMP and precipitated again in ethanol, and filtered by suction to purify the polyimide. Finally, the purified polyimide was dried under vacuum for later use. The polyimide solid after vacuum drying was first dissolved in NMP, and then BC was added to prepare a polyimide solution PI-2. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 67096 g / mol as measured by GPC.

[0104] Synthesis Example 9

[0105] N2 was introduced into a 500 mL four-necked flask equipped with a stirring device. 7.0 g (0.033 mol) of DA-3, 6.60 g (0.033 mol) of DA-4, and 164.28 g of NMP were added in sequence. After dissolution, 29.70 g (0.033 mol) of CA-2 and 6.46 g (0.033 mol) of CA-3 were added, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, NMP and BC were added to prepare a polyamic acid solution PAA-7. The polymer content in the solution was 6 wt%, the NMP content was 70 wt%, the BC content was 24 wt%, and the polymer molecular weight Mw was 66125 g / mol as measured by GPC.

[0106] Synthesis of Synthesis Example 10B-1

[0107]

[0108] Add 20 g (0.059 mol) of 2,6-naphthalenediamine-bis-4-phenylamine and an appropriate amount of methanol into a three-necked flask, heat up to 50 °C, add a mixed solution of 21.83 g (0.236 mol) of epichlorohydrin and methanol into a constant pressure dropping funnel, and slowly drip it. After the epichlorohydrin is completely dripped, keep the temperature for reaction for 6 h. During this period, after monitoring the reaction to be complete by TLC, slowly drip an appropriate amount of triethylamine solution through the constant pressure dropping funnel for the ring-closure reaction of epichlorohydrin. After reacting for 2 h, drip a mixed solution of 7.61 g (0.118 mol) of chloroethane and methanol through the constant pressure dropping funnel and heat up to 80 °C. After reacting for 3 h, distill off the reaction solvent under reduced pressure. Then dissolve the concentrated solution in dichloromethane, wash the organic phase with deionized water until neutral, and distill off the solvent again under reduced pressure to obtain the target product B-1, a pale yellow transparent liquid, with a yield of 85%.

[0109] The NMR information of B-1 is as follows:

[0110] 1 HNMR(500MHz, CDCl3): δ: 7.74(s, 2H), 7.46(s, 2H), 7.10(s, 2H), 7.07 - 7.04(m, 4H), 6.71 - 6.68(m, 4H), 3.69 - 3.62(m, 8H), 3.36 - 3.34(d, 4H), 3.30 - 3.27(d, 4H), 2.93 - 2.92(d, 4H), 2.84 - 2.83(d, 4H), 1.29(s, 6H).

[0111] Synthesis of Example 11 B-2

[0112]

[0113] Add 20 g (0.059 mol) of 2,6-naphthalenediamine-bis-4-phenylamine and an appropriate amount of methanol into a three-necked flask, heat up to 50 °C, add a mixed solution of 21.83 g (0.236 mol) of epichlorohydrin and methanol into a constant pressure dropping funnel, and slowly drip it. After the epichlorohydrin is completely dripped, react for 6 h. During this period, after monitoring the reaction to be complete by TLC, slowly drip an appropriate amount of triethylamine solution through the constant pressure dropping funnel for the ring-closure reaction of epichlorohydrin. After reacting for 2 h, drip a methanol solution of 12.33 g (0.118 mol) of chlorotrifluoromethane through the constant pressure dropping funnel and heat up to 80 °C. After reacting for 3 h, distill off the reaction solvent under reduced pressure. Then dissolve the concentrated solution in dichloromethane, wash the organic phase with deionized water until neutral, and distill off the solvent again under reduced pressure to obtain the target product B-2, a pale yellow transparent liquid, with a yield of 80%.

[0114] The NMR information of B-2 is as follows:

[0115] 1 HNMR(500 MHz, CDCl3): δ: 7.96 (s, 2H), 7.81 (s, 2H), 7.49 (s, 2H), 7.32 - 7.29 (m, 4H), 6.69 - 6.67 (m, 4H), 3.68 (s, 4H), 3.36 - 3.34 (d, 4H),

[0116] 3.30 - 3.27 (d, 4H), 2.93 - 2.92 (d, 4H), 2.84 - 2.83 (d, 4H).

[0117] Synthesis of Synthesis Example 12B - 3

[0118]

[0119]

[0120] Add 20 g (0.059 mol) of 2,6 - naphthalenediamine - bis - 4 - aniline and an appropriate amount of methanol into a three - necked flask, heat up to 50 °C. In a constant - pressure dropping funnel, add a mixed solution of 21.83 g (0.236 mol) of epichlorohydrin and methanol, and slowly drip it. After the epichlorohydrin is completely added, react for 6 h. During this period, monitor the reaction by TLC until it is complete, then slowly drip an appropriate amount of triethylamine solution through the constant - pressure dropping funnel for the ring - closing reaction of epichlorohydrin. After reacting for 2 h, drip a mixed solution of 13.99 g (0.118 mol) of chlorocyclohexane and methanol through the constant - pressure dropping funnel, and heat up to 80 °C. After reacting for 3 h, distill off the reaction solvent under reduced pressure. Then dissolve the concentrated solution in dichloromethane, wash the organic phase with deionized water until it is neutral, and distill off the solvent again under reduced pressure to obtain the target product B - 3, a light - yellow transparent liquid, with a yield of 81%.

[0121] 1H - NMR information of B - 3 is as follows:

[0122] 1 HNMR(500 MHz, CDCl3): δ: 7.76 (s, 2H), 7.39 (s, 2H),

[0123] 7.02 - 7.00 (m, 4H), 6.94 (s, 2H), 6.70 - 6.68 (m, 4H), 3.77 (s, 2H), 3.68 (s, 4H), 3.36 - 3.34 (d, 4H), 3.30 - 3.27 (d, 4H), 2.93 - 2.92 (d, 4H), 2.84 - 2.83 (d, 4H), 1.96 - 1.94 (d, 4H), 1.70 - 1.68 (d, 4H), 1.62 - 1.60 (d, 2H), 1.57 - 1.55 (d, 4H), 1.42 - 1.40 (d, 4H), 1.35 - 1.32 (d, 2H).

[0124] Synthesis of Synthesis Example 13B-4

[0125]

[0126] 20 g (0.059 mol) of 2,6-naphthalenediamine-bis-4-aniline and an appropriate amount of methanol were added to a three-necked flask, and the temperature was raised to 50 °C. A mixed solution of 21.83 g (0.236 mol) of epichlorohydrin and methanol was added to a constant pressure dropping funnel and slowly added dropwise. After the addition of epichlorohydrin was complete, the reaction was carried out for 6 h. During this period, after monitoring the reaction to completion by TLC, an appropriate amount of triethylamine solution was slowly added dropwise using a constant pressure dropping funnel for the ring-closing reaction of epichlorohydrin. After the reaction for 2 h, a mixed solution of 22.26 g (0.118 mol) of 4-chlorobiphenyl and methanol was added dropwise through a constant pressure dropping funnel, and the temperature was raised to 80 °C. After the reaction for 3 h, the reaction solvent was removed by distillation under reduced pressure. Then the concentrated solution was dissolved in dichloromethane, and the organic phase was washed with deionized water until neutral. The solvent was removed again by distillation under reduced pressure to obtain the target product B-4, a pale yellow transparent liquid, with a yield of 86%.

[0127] The NMR information of B-4 is as follows:

[0128] 1 HNMR(500MHz, CDCl3): δ: 7.86(s,2H), 7.72(s,2H),

[0129] 7.67 - 7.64(m,4H), 7.61 - 7.58(m,4H), 7.45 - 7.35(m,6H), 7.20(s,2H),

[0130] 7.17 - 7.14(m,4H), 7.10 - 7.08(m,4H), 6.76 - 6.74(m,4H), 3.68(s,4H),

[0131] 3.36 - 3.34(d,4H), 3.30 - 3.27(d,4H), 2.93 - 2.92(d,4H), 2.84 - 2.83(d,4H).

[0132] Example 1

[0133] 100.00 g of the polyimide solution PAA-1 obtained in Synthesis Example 1 and 0.03 g of the epoxy group-containing compound B-1 were stirred at room temperature (25 °C) for 3 hours to obtain a liquid crystal aligning agent 1.

[0134] Examples 2 - 18

[0135] 100.00 g of different types of polyimide solutions or polyamic acid solutions obtained in the synthesis examples and epoxy group-containing compounds were stirred at room temperature (25 °C) for 3 hours to obtain a series of liquid crystal aligning agents. Among them, the specific selections of the polyimide solutions or polyamic acid solutions and the epoxy group-containing compounds are shown in Table 1 below.

[0136] Comparative Examples 1-4

[0137] 100.00 g of the polyamic acid solution obtained in the synthesis example and the epoxy group-containing compound (if any) were stirred at room temperature (25 °C) for 3 hours to obtain a series of liquid crystal aligning agents. Among them, the specific selections of the polyamic acid solution and the epoxy group-containing compound are shown in Table 1 below.

[0138] Table 1

[0139]

[0140]

[0141] Application Example 1

[0142] The liquid crystal aligning agents in each example and comparative example were filtered with a PTFE membrane filter, and then coated on a glass substrate having a conductive film composed of an ITO electrode by a spin coating method to form a pre-coating. Then, pre-curing was carried out on a hot plate at a temperature of 80 °C for 5 minutes, and main curing was carried out in a circulating oven at a temperature of 230 °C for 60 minutes. After the rubbing alignment treatment, a liquid crystal alignment film was obtained.

[0143] Application Example 2

[0144] Two glass substrates with liquid crystal alignment films prepared above were taken, with the film surfaces on the inner side and the rubbing directions opposite. A 4-μm spacer was sandwiched in the middle, and the two glass substrates were combined. The surrounding parts were bonded with a sealant to obtain an empty cell. Liquid crystal MLC-7028 (Merck) was injected into the empty cell by a vacuum injection method, the injection hole was sealed, and polarizers were attached to both outer sides of the substrate to fabricate an FFS-driven liquid crystal cell.

[0145] Performance Verification

[0146] The above-prepared FFS-driven liquid crystal cells were evaluated for each test item, and the test methods are as follows.

[0147] (1) Evaluation of Abrasion Resistance

[0148] For the upper and lower substrates of the FFS-driven liquid crystal cells prepared from the liquid crystal aligning agents of the examples and comparative examples, polarizers with orthogonal polarization axis directions were attached. Then, the FFS-driven liquid crystal cells were placed on top of the backlight panel, and the rubbing streaks of the FFS-driven liquid crystal cells lit at a voltage near the threshold (the voltage when the relative transmittance of the FFS-driven liquid crystal cell was around 10%) were observed with a magnifying glass at 5 times magnification. The lighter the rubbing streaks, the better the rubbing resistance performance of the alignment film.

[0149] The evaluation results of the rubbing resistance performance are as follows:

[0150] √: No rubbing streaks were observed with the magnifying glass, and the rubbing resistance performance is good;

[0151] ○: Slight rubbing streaks were observed with the magnifying glass, but no rubbing streaks were observed with the naked eye, and the rubbing resistance performance is average;

[0152] △: Slight rubbing streaks were observed with the naked eye, and the rubbing resistance performance is poor;

[0153] ×: Obvious rubbing streaks were observed with the naked eye, and the rubbing resistance performance is extremely poor.

[0154] (2) Evaluation of liquid crystal alignment

[0155] For the FFS-driven liquid crystal cells prepared from the liquid crystal aligning agents of the examples and comparative examples, abnormal regions where brightness changes occurred when a voltage of 5 V was turned on and off were observed with a microscope at a magnification of 50 times. The case where no abnormal regions were observed was defined as "excellent" alignment, and the case where abnormal regions were observed was defined as "poor".

[0156] (3) Evaluation of residual direct current charge (RDC)

[0157] The FFS-driven liquid crystal cells prepared from the liquid crystal aligning agents of the examples and comparative examples were placed in an oven at 60 °C, a DC voltage of 5 V was applied to the FFS-driven liquid crystal cells for 1 hour, and after a short circuit for 1 second, the voltage value of the FFS-driven liquid crystal cells was measured, and the voltage value after 10 minutes was used as the RDC of the FFS-driven liquid crystal cells.

[0158] (4) Evaluation of voltage holding ratio (VHR)

[0159] After applying a voltage of 5 V to the FFS-driven liquid crystal cells prepared from the liquid crystal aligning agents of the examples and comparative examples with an application time of 60 μs and a span of 167 ms, the voltage holding ratio 167 ms after the application was released was measured. During the measurement, the temperature of the FFS-driven liquid crystal cells was set to 25 °C and 60 °C respectively for the measurement.

[0160] The evaluation results are shown in Table 2.

[0161] Table 2

[0162]

[0163]

[0164] As can be seen from Examples 1 to 5 in Table 2 above, as the addition amount of the epoxy group-containing compound of the present invention increases, the rubbing resistance of the liquid crystal alignment film gradually increases, the alignment property of the liquid crystal display element and the release performance of the DC charge become better. At the same time, the voltage holding ratio of the liquid crystal display element shows an increasing trend, and the thermal stability of the voltage holding ratio is better. When the addition amount of the epoxy group-containing compound reaches a certain proportion, the rubbing resistance and the alignment property of the liquid crystal display element still remain good, but the voltage holding ratio of the liquid crystal display element begins to decline and the thermal stability becomes poor.

[0165] By comparing the examples and comparative examples in Table 2 above, it can be seen that the rubbing resistance of the liquid crystal alignment film added with the epoxy group-containing compound of the present invention is improved, the alignment property of the liquid crystal display element added with the epoxy group-containing compound of the present invention is improved, the release rate of the DC charge is increased, the voltage holding ratio is increased, and the electrical properties and thermal stability are better.

[0166] Therefore, the liquid crystal aligning agent containing the epoxy group-containing compound of the present invention can significantly improve the rubbing resistance and liquid crystal alignment property of the liquid crystal alignment film, and can also improve the voltage holding ratio and thermal stability of the liquid crystal display element. Therefore, the liquid crystal display element obtained from the liquid crystal aligning agent of the present invention has better reliability and optoelectronic performance, and can be applied to scenarios with long-term continuous driving, high temperature conditions, and high display quality requirements.

Claims

1. A compound containing an epoxy group, characterized in that, Having the structural formula represented by formula (1): Formula (1) In formula (1), R represents H, an alkyl group having 1 to 5 carbon atoms, a haloalkyl group having 1 to 5 carbon atoms, cyclohexyl, phenyl or biphenyl.

2. The compound according to claim 1, wherein Any one of the compounds represented by the structures shown in the following (B-1) to (B-4): （B-1） （B-2） （B-3） （B-4）。 3. A liquid crystal aligning agent, characterized in that, Comprising a polymer and an epoxy group-containing compound, and the epoxy group-containing compound is at least one of the epoxy group-containing compounds described in claim 1 or 2.

4. The liquid crystal aligning agent according to claim 3, wherein The polymer is at least one of polyamic acid and polyimide.

5. The liquid crystal aligning agent according to claim 3, wherein It further includes a solvent, and the solvent is an organic solvent.

6. The liquid crystal aligning agent according to claim 5, wherein The solvent is at least one of N-methylpyrrolidone, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, N,N-dimethylformamide, N,N-dimethylacetamide, and butyl cellosolve.

7. The liquid crystal aligning agent according to any one of claims 3-6, characterized in that, Based on 100 parts by weight of the polymer, the amount of the epoxy group-containing compound used is 0.5 to 20 parts by weight.

8. The liquid crystal aligning agent according to claim 5 or 6, characterized in that, Based on 100 parts by weight of the polymer, the amount of the solvent used is 500 to 5000 parts by weight.

9. A liquid crystal alignment film, characterized in that, Made from the liquid crystal aligning agent according to any one of claims 3 to 8.

10. A liquid crystal display element, characterized in that, Including the liquid crystal alignment film described in claim 9.

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