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

Abstract

The invention provides a liquid crystal alignment film capable of improving charge relaxation speed and having low AC ghosting, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal display element comprising the liquid crystal alignment film. The liquid crystal aligning agent contains a polymer (A) having a specific structure.

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent, and in particular to a liquid crystal alignment film capable of improving charge relaxation speed and having low AC residual image, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal display element comprising the liquid crystal alignment film. Background Art

[0002] Known liquid crystal display elements are widely used as display components of personal computers, smart phones, cellular phones or television sets. Liquid crystal display elements may include, for example, a liquid crystal layer sandwiched between a component substrate and a color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an orientation film for controlling the orientation of liquid crystal molecules in the liquid crystal layer, and a thin film transistor (TFT) for switching the electronic signal supplied to the pixel electrode. As for the driving method of liquid crystal molecules, there are known longitudinal electric field methods such as TN (Twisted Nematic) method and VA (Vertical Alignment) method, and transverse electric field methods such as IPS (In-Plane Switching) method and FFS (Fringe Field Switching) method.

[0003] At present, the most popular liquid crystal alignment film in the industry is formed on the electrode substrate by rubbing the surface of the film composed of polyamic acid and / or its polyimide obtained by imidization with cotton, nylon or polyester cloth in one direction. The friction treatment is a simple and highly productive industrial common method. However, with the high performance, high precision and large-scale liquid crystal display elements, the surface of the alignment film is scarred by dust, mechanical force and static electricity generated by the friction treatment, which leads to various problems such as unevenness in the alignment treatment surface. As an orientation treatment method to replace the friction treatment, it is known that there is a photo-orientation method that imparts liquid crystal orientation ability by irradiating polarized radiation. For the photo-orientation method, Japanese Patent Publication No. 9-297313 has disclosed the use of photoisomerization reaction, photo-crosslinking reaction or photo-decomposition reaction. However, the known liquid crystal alignment film obtained by the photo-orientation method contains residual charges in the liquid crystal alignment film, which affects the overall orientation and transmittance, and then produces afterimages, which cannot meet the application requirements.

[0004] An object of the present invention is to provide a liquid crystal alignment film having a fast charge relaxation rate and low AC image sticking, a liquid crystal alignment agent for obtaining the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film.

[0005] The inventors of the present invention have made intensive researches to achieve the above-mentioned problems and have found that a liquid crystal alignment film formed by a liquid crystal alignment agent containing a polymer with a specific structure is very effective in achieving the above-mentioned purpose, thereby completing the present invention. Summary of the invention

[0006] In view of this, one aspect of the present invention is to provide a liquid crystal alignment agent, which includes a polymer (A). The liquid crystal alignment film formed by using the liquid crystal alignment agent can improve the charge relaxation speed of the liquid crystal display element and reduce AC image sticking. Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed by using the above-mentioned liquid crystal alignment agent.

[0007] Another aspect of the present invention is to provide a liquid crystal display element, which includes the aforementioned liquid crystal alignment film and has a faster charge relaxation speed and lower AC image sticking.

[0008] According to the above-mentioned aspect of the present invention, a liquid crystal alignment agent is proposed. The liquid crystal alignment agent of the present invention contains a polymer (A). The ideal implementation aspect of the liquid crystal alignment agent of the present invention can be listed as a liquid crystal alignment agent containing a polymer (A) and an organic solvent. In addition, the liquid crystal alignment agent of the present invention may also contain a polymer other than the polymer (A) (such as a polymer (B) described later).

[0009] Polymer (A)

[0010] The polymer (A) of the present invention may be selected from at least one polymer selected from the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic acid derivative component (a1) and a diamine component (a2), and an imidized polymer of the polyimide precursor. For example, the polymer (A) may include a polyimide precursor having an imide precursor structure such as polyamic acid and polyamic acid ester.

[0011] The polyimide precursor of the polymer (A) may include a structure represented by the following formula (I).

[0012]

[0013] When the polymer (A) does not include the structure represented by the formula (I), a liquid crystal display element including a liquid crystal alignment film prepared using the polymer (A) tends to have a slow charge relaxation rate and a high AC image sticking problem.

[0014] In formula (I), X 1 With X 1 ' each independently represents a chain hydrocarbon group having 1 to 10 carbon atoms; 2 With X 2 ' independently represent -O-, -S-, -CO- or -COO-; X 3 With X 3' respectively independently represent a chain hydrocarbon group having 1 to 10 carbon atoms or a single bond; 1 , X 1 ′、X 3 With X 3 ' cannot all be single bonds; Ring Z represents an aromatic hydrocarbon ring, diphenyl ether or a nitrogen-containing heterocyclic ring; B 1 and B 2 Each independently represents a divalent organic group as shown in the following structure, B 1 With B 2 Not the same structure; "*" represents the bond position.

[0015]

[0016] In the structure shown above, R 4 represents an alkylene group having 1 to 5 carbon atoms or -O-; R 5 represents a hydrogen atom, a methyl group, a hydroxyl group or a methoxy group.

[0017] The aforementioned chain hydrocarbon group refers to a straight-chain or branched hydrocarbon group having no ring structure in the main chain and consisting only of a chain structure, and may be saturated or unsaturated.

[0018] In some specific examples, the chain hydrocarbon group having a carbon number of 1 to 10 may include saturated and unsaturated chain hydrocarbon groups. Among them, the saturated chain hydrocarbon group may be a saturated straight chain or branched chain hydrocarbon group. The saturated straight chain hydrocarbon group may be, for example, a methylene group, an ethyl group, a propanediyl group, a butanediyl group, a pentanediyl group, a hexanediyl group, a heptanediyl group, an octanediyl group, a nonanediyl group or a decanediyl group. The saturated branched chain hydrocarbon group may be, for example, a second butanediyl group, a third butanediyl group, an isopentanediyl group, a third pentanediyl group, an isooctanediyl group, a 2-ethylhexanediyl group, a third octanediyl group, an isononanediyl group or an isodecanediyl group. The unsaturated chain hydrocarbon group may include an unsaturated chain hydrocarbon group having an unsaturated bond (such as an olefinic bond and / or an acetylenic bond), and these groups may also be straight chain or branched chain. For example, the unsaturated chain hydrocarbon group may be, for example, ethylenediyl, heptenediyl, 2-butenediyl, 3-methyl-4-ethyl-1-hexenediyl, propynyl, 2-hexynyl, 3-methyl-1-pentynyl or 3-ethyl-1-heptynyl. The aforementioned ring Z may be a group formed by removing two hydrogen atoms from the ring portion of an aromatic hydrocarbon ring, a group formed by removing one hydrogen atom from each of the two side ring portions of diphenyl ether, or a group formed by removing two hydrogen atoms from the ring portion of a nitrogen-containing heterocyclic ring, and the aforementioned ring portion may also have a substituent. In some specific examples, the aromatic hydrocarbon ring, diphenyl ether or nitrogen-containing heterocyclic ring may include, but is not limited to, a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a diphenyl ether ring, a pyridine ring, a pyrimidine ring, a pyrazine ring or a pyridazine ring. In formula (I), X 1 , X 1 ' can be bonded to the para, ortho or meta position of ring Z respectively.

[0019] In some embodiments, the aforementioned formula (I) is at least one selected from the group consisting of the structures represented by the following formula (I-1) and formula (I-2).

[0020]

[0021] The polymer (A) of the present invention is selected from at least one of a polyimide precursor obtained by reacting a tetracarboxylic acid derivative component (a1) with a diamine component (a2) containing a diamine compound (a2-1) of formula (A21), and an imidized polymer of the polyimide precursor. Specific examples of the polymer (A) include, for example, a polyimide precursor having an imide precursor structure such as polyamic acid and polyamic acid ester, or an imidized product (i.e., polyimide) of the polyimide precursor.

[0022]

[0023] In formula (A21), X 1 , X 1 ′、X 2 , X 2 ′、X 3 , X 3 ' and ring Z are as defined above.

[0024] Tetracarboxylic acid derivative component (a1)

[0025] In addition to the tetracarboxylic acid dianhydride compound, the tetracarboxylic acid dianhydride derivative of the present invention, such as tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide, can be used as the tetracarboxylic acid derivative component (a1) to be reacted with the diamine component (a2). The tetracarboxylic acid derivative component (a1) can be used alone as one tetracarboxylic acid dianhydride compound or its derivative, or a mixture of plural kinds thereof can be used.

[0026] Alicyclic tetracarboxylic dianhydride (a1-1)

[0027] The tetracarboxylic acid derivative component (a1) may include an alicyclic tetracarboxylic dianhydride compound or a derivative thereof (a1-1) as shown in the following formula (A11). The alicyclic tetracarboxylic dianhydride or a derivative thereof as shown in formula (A11) may be composed of a single tetracarboxylic dianhydride compound or a derivative thereof, or may be composed of a plurality of tetracarboxylic dianhydride compounds or derivatives thereof.

[0028]

[0029] In formula (A11), R 1 To R 4 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, 1 To R 4 are the same or different, and R 1 , R 2 , R 3 and R 4 At least one of is not a hydrogen atom.

[0030] In Ri, R 2 , R 3 and R 4 In the case of a steric barrier structure, the liquid crystal orientation of the liquid crystal alignment agent will be poor. 1 , R 2 , R 3 and R 4 Preferred are hydrogen atom, methyl group or ethyl group, among which methyl group is more preferred.

[0031] Specific examples of the alicyclic tetracarboxylic dianhydride compound or its derivative (a1-1) as represented by formula (A11) may include but are not limited to the compounds represented by the following formulas (A11-1) to (A11-8). In terms of liquid crystal orientation, formula (A11-1) is preferred.

[0032]

[0033] The above-mentioned alicyclic tetracarboxylic dianhydride compound or its derivative (a1-1) may be used alone or in combination of plural kinds.

[0034] Based on the total usage of the tetracarboxylic acid derivative component (a1) being 100 mol, the usage of the alicyclic tetracarboxylic dianhydride or its derivative (a1-1) represented by formula (A11) can be 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0035] When the tetracarboxylic acid derivative component (a1) of the polymer (A) comprises an alicyclic tetracarboxylic dianhydride compound represented by formula (A11) or a derivative thereof (a1-1), the liquid crystal alignment film prepared therefrom can more effectively reduce AC image sticking of a liquid crystal display element.

[0036] Other tetracarboxylic dianhydride compounds (a1-2)

[0037] Other tetracarboxylic dianhydride compounds (a1-2) may include tetracarboxylic dianhydride compounds represented by the following formula (A12) and derivatives thereof.

[0038]

[0039] In formula (A12), X 1 ' can represent the structures shown in the following formulae (A12-1) to (A12-32), wherein "*" represents the bonding position.

[0040]

[0041]

[0042]

[0043]

[0044] In formula (A12-5) and formula (A12-6), X 1 1′ and X 12 'respectively independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide, and in formula (A12-6), multiple X 12' may be the same or different. a1 in formula (A12-5) represents an integer of 0 or 1. a1 in formula (A12-6) represents an integer of 0 or 1. In formula (A12-14), X 13 ' independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and multiple X 13 ' may be the same or different from each other. Based on the viewpoint of liquid crystal orientation, X 13 ' preferably represents a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and more preferably represents a hydrogen atom or a methyl group.

[0045] In some specific examples, the aforementioned formula (A12-5) and formula (A12-6) may include but are not limited to the structures shown below.

[0046]

[0047]

[0048] The above-mentioned other tetracarboxylic dianhydride compounds (a1-2) may be used alone or in combination of plural kinds.

[0049] Based on the total usage of the tetracarboxylic acid derivative component (a1) being 100 mol, the usage of the other tetracarboxylic dianhydride compound (a1-2) may be 0 mol to 70 mol, preferably 0 mol to 60 mol, and more preferably 0 mol to 50 mol.

[0050] Diamine component (a2)

[0051] The diamine component (a2) of the present invention may include a diamine compound (a2-1), a diamine compound (a2-2), a diamine compound (a2-3), a diamine compound (a2-4) and other diamine compounds (a2-5).

[0052] Diamine compound (a2-1)

[0053] The diamine component (a2) of the present invention comprises a diamine compound (a2-1) represented by the following formula (A21).

[0054]

[0055] In formula (A21), X 1 , X 1 ′、X 2 , X 2 ′、X 3 , X 3 ′、B 1 , B 2 and ring Z are as defined above.

[0056] Preferably, X 3 With X 3 ' each independently represents a single bond, and X 1 With X 1 ' cannot all be single bonds. 3 With X 3 When ' independently represent a single bond, the resulting liquid crystal alignment film can more effectively improve the charge relaxation speed of the liquid crystal display element.

[0057] In other embodiments, ring Z preferably represents a phenylene group. When ring Z in formula (A21) represents a phenylene group, the liquid crystal alignment film prepared using the ring Z can more effectively improve the charge relaxation speed of the liquid crystal display element.

[0058] In some embodiments, the diamine compound (a2-1) represented by formula (A21) is at least one selected from the group consisting of the structures represented by the following formula (A21-1) and formula (A21-2).

[0059]

[0060] When the diamine compound (a2-1) represented by formula (A21) includes at least one of formula (A21-1) and formula (A21-2), the liquid crystal alignment film prepared therefrom can further improve the charge relaxation speed of the liquid crystal display element.

[0061] In some specific examples, the diamine compound (a2-1) may include but is not limited to the compounds represented by the following formulae (A21-3) to (A21-10).

[0062]

[0063]

[0064] The main synthesis methods of the diamine compound (a2-1) are described in detail below. The methods described below are only examples and the present invention is not limited thereto.

[0065] As shown in the following reaction formula (A), the diamine compound (a2-1) of the present invention is obtained by reducing a dinitro compound to convert the nitro group into an amino group. This reaction formula records the diamine compound (A21-3) of the embodiment, which is only used as an example.

[0066]

[0067] The reduction method of the dinitro compound is not particularly limited. For example, palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, carbon-supported platinum sulfide catalyst (PtS / C catalysts, Platinumsulfided on carbon) and the like can be used as catalysts, and the reduction is carried out by hydrogen, hydrazine and hydrogen chloride in solvents such as ethyl acetate, toluene, tetrahydrofuran, dioxane and alcohols. An autoclave can also be used as needed to carry out the reduction reaction under pressure. On the other hand, when the substituent structure of the hydrogen atom of the substituted benzene ring or saturated hydrocarbon group contains an unsaturated bond, when palladium carbon or platinum carbon is used, the unsaturated bond may be reduced to a saturated bond. Therefore, it is preferred to use a transition metal such as reduced iron, tin, tin chloride as a catalyst for the reduction condition.

[0068] The reaction temperature of reaction formula (A) can be appropriately set according to the reaction method, preferably -20°C to 200°C, more preferably 0°C to 150°C.

[0069] In the synthesis of dinitro compounds, as shown in the following reaction formulas (B) and (C), a nitro compound containing a leaving group (X) can be obtained by first reacting a commercially available nitrohydroxy aromatic derivative, nitrohydroxypyridine derivative, nitrohydroxypyrimidine derivative, or nitrohydroxydiphenyl ether derivative with an aromatic hydrocarbon ring derivative, diphenyl ether derivative, or nitrogen-containing heterocyclic derivative substituted with a leaving group (X). The nitro compound containing a leaving group (X) is then reacted with another nitrohydroxy aromatic derivative, nitrohydroxypyridine derivative, nitrohydroxypyrimidine derivative, or nitrohydroxydiphenyl ether derivative to obtain a dinitro compound. Preferred leaving groups (X) include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, toluene sulfonates, and mesylates.

[0070]

[0071] There is no particular limitation on the conduct of reaction formula (B) and reaction formula (C), and they can be conducted in the presence of a base. As long as the target product can be synthesized, the base used is not particularly limited, and examples thereof include inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, sodium hydride, and organic bases such as pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and tributylamine. Depending on the situation, when a palladium catalyst or a copper catalyst is used in combination, the yield can be increased. Specific examples of palladium catalysts include, but are not limited to, dibenzylideneacetone palladium (Bis(dibenzylideneacetone)palladium), tris(dibenzylideneacetone)dipalladium (Tris(dibenzylideneacetone)dipalladium), 1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II), and the like. The reaction solvent may be a polar aprotic solvent such as acetonitrile, dimethylformamide (DMF), acetone, dimethylacetamide (DMAc). From the viewpoint of easy synthesis, the base is preferably potassium carbonate. The reaction temperature of reaction formula (B) and reaction formula (C) is appropriately set according to the reaction method, preferably -20°C to 250°C, more preferably 0°C to 200°C.

[0072] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-1) may be 10 mol to 90 mol, preferably 12.5 mol to 80 mol, and more preferably 15 mol to 70 mol.

[0073] If the diamine component (a2) of the polymer (A) does not contain the diamine compound (a2-1) represented by formula (A21), a liquid crystal display element containing a liquid crystal alignment film prepared using the diamine component (a2-1) is prone to problems such as a slower charge relaxation rate and a higher AC image sticking.

[0074] Diamine compound (a2-2)

[0075] The diamine component (a2) of the present invention may include a diamine compound (a2-2) represented by the following formula (A22).

[0076]

[0077] In formula (A22), Ar represents a divalent aromatic group of a benzene ring, biphenyl or naphthalene ring, and the hydrogen atoms of the benzene ring or biphenyl structure may be substituted by a monovalent substituent group or may not be substituted; m and n each independently represent an integer from 1 to 3; and any hydrogen atom on the benzene ring to which the amino groups at both ends are bonded may be substituted by a monovalent substituent group or may not be substituted.

[0078] The monovalent substituent group on the benzene ring, biphenyl structure or naphthalene ring represented by the aforementioned Ar may be, for example, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 3 carbon atoms, a cyano group or a nitro group, etc., preferably a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a fluoroalkyl group having 1 to 3 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

[0079] The monovalent substituent groups on the benzene ring to which the two terminal amine groups are bonded may be, for example, the monovalent substituent groups listed above for the Ar group, and the preferred embodiments are also as described above.

[0080] For example, the divalent aromatic group represented by Ar may include, but is not limited to, 1,4-phenylene, 1,3-phenylene, 2-methyl-1,4-phenylene, 2-ethyl-1,4-phenylene, 2-propyl-1,4-phenylene, 2-isopropyl-1,4-phenylene, 2-methoxy-1,4-phenylene, 2-ethoxy-1,4-phenylene, 2-propoxy-1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-dimethyl-1,4-phenylene, 4-methyl-1,3-phenylene, 5-methyl-1,3-phenylene, 4-fluoro-1,3-phenylene, 2,3,5,6-tetramethyl-1,4-phenylene, biphenyl-4,4′-diyl, 2-methylbiphenyl-4,4′-diyl, 2-ethylbiphenyl-4,4′-diyl, 2-propylbiphenyl-4,4'-diyl, 2-methoxybiphenyl-4,4'-diyl, 2-ethoxybiphenyl-4,4'-diyl, 2-fluorobiphenyl-4,4'-diyl, 3-methylbiphenyl-4,4'-diyl, 3-ethylbiphenyl-4,4'-diyl, 3-propylbiphenyl-4,4'-diyl, 3-methoxybiphenyl-4,4'-diyl, 3-ethoxybiphenyl-4, The diamine compound (a2-2) represented by formula (A22) can be selected from at least one of the group consisting of the structures represented by the following formulae (A22-1) to (A22-3).

[0081]

[0082] In formula (A22-1) to formula (A22-3), any hydrogen atom on the benzene ring to which the two terminal amine groups are bonded, or any hydrogen atom on the divalent benzene ring, biphenyl or naphthalene ring bonded to the alkylene group, can be substituted by a monovalent substituent group, wherein the monovalent substituent group is, for example, a monovalent substituent group listed for the aforementioned Ar group, and preferred embodiments are also as described above. The definitions of m and n are as described above. In some specific examples, the diamine compound (a2-2) shown in formula (A22) may include the compounds listed below.

[0083]

[0084]

[0085] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-2) may be 10 mol to 90 mol, preferably 11 mol to 70 mol, and more preferably 12 mol to 50 mol.

[0086] When the diamine component (a2) of the polymer (A) includes a diamine compound (a2-2) represented by formula (A22), the liquid crystal alignment film prepared therefrom can more effectively reduce AC image sticking of a liquid crystal display element.

[0087] Diamine compound (a2-3)

[0088] The diamine component (a2) of the present invention may include a diamine compound (a2-3), and the diamine compound (a2-3) may include a diamine compound represented by the following formula (A23-1) or formula (A23-2).

[0089]

[0090] In formula (A23-1), Y 31 represents a divalent organic group as shown in the following formula (A23-3). 32 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 33 Each independently represents a divalent organic group represented by the following formula (A23-3′).

[0091]

[0092] In formula (A23-3), Ar each independently represents a divalent benzene ring, a biphenyl structure or a naphthalene ring, and the hydrogen atoms of the benzene ring, the biphenyl structure or the naphthalene ring may be substituted by a monovalent substituent or may not be substituted; Y 31 ' represents -(CH 2 ) n -, n represents an integer from 2 to 18, and -(CH 2 )n -At least one of -CH 2 - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p1 represents an integer of 0 or 1; "-*" represents a bonding position.

[0093] In formula (A23-3′), Ar′ independently represents a divalent benzene ring or a biphenyl structure, and the hydrogen atoms of the benzene ring or the biphenyl structure may be substituted by a monovalent substituent or may not be substituted; Y 33 ' represents -(CH 2 ) n -, n represents an integer from 2 to 18, and -(CH 2 ) n -At least one of -CH 2 - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p2 represents an integer of 0 or 1; "*" represents a bonding position.

[0094] The monovalent substituent group of the aforementioned benzene ring, biphenyl structure, or naphthalene ring may be, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, a cyano group, or a nitro group.

[0095] From the viewpoint of improving the orientation of liquid crystals, the divalent organic group represented by formula (A23-3) may preferably include groups represented by the following formulae (A23-3-1) to (A23-3-16), wherein "*" represents a bonding position.

[0096]

[0097]

[0098] In formula (A23-3-14), each of m independently represents an integer of 1 to 3.

[0099] From the viewpoint of improving the liquid crystal alignment, the divalent organic group represented by the formula (A23-3′) may preferably include groups represented by the formulae (A23-3-7) to (A23-3-16).

[0100] When the diamine compound (a2-3) comprises a plurality of diamine compounds as shown in formula (A23-1), it is preferably Y in formula (A23-1): 31 The diamine compounds represented by formula (A23-3-1) to formula (A23-3-14) and Y in formula (A23-1) 31It represents a combination of diamine compounds of formula (A23-3-15) to formula (A23-3-16).

[0101] In some specific examples, the diamine compound represented by the aforementioned formula (A23-2) may include but is not limited to the diamine compounds represented by the following formulas (A23-2-1) to (A23-2-5).

[0102]

[0103]

[0104] The aforementioned diamine compounds (a2-3) may be used alone or in combination of two or more.

[0105] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-3) may be 0 mol to 80 mol, preferably 5 mol to 70 mol, and more preferably 10 mol to 60 mol.

[0106] Diamine compound (a2-4)

[0107] Based on the viewpoint of improving the voltage holding rate of the liquid crystal display element, the molecular structure of the polymer (A) may selectively have an -N(D)- group (wherein D represents a carbamate-based protecting group). The polymer (A) having an -N(D)- group can be obtained by using a monomer having an -N(D)- group as at least a part of the reaction raw material, or by using it as a capping agent as described later. In some specific examples, the monomer having an -N(D)- group may be, for example, a diamine compound (a2-4) having an -N(D)- group. For example, the carbamate-based protecting group may include, but is not limited to, a tert-butyloxycarbonyl group and a 9-fluorenylmethoxycarbonyl group.

[0108] Preferably, the diamine compound (a2-4) having an -N(D)- group includes a diamine compound having at least one aromatic group such as a benzene ring. More preferably, the diamine compound (a2-4) having an -N(D)- group includes a diamine compound having at least one aromatic group such as a benzene ring, and the residue other than the substituent (D) is a diamine compound having a carbon number of 6 to 30. In some specific examples, the diamine compound (a2-4) having an -N(D)- group may include but is not limited to the diamine compounds shown in the following formulas (A24-1) to (A24-10).

[0109]

[0110]

[0111] The aforementioned diamine compounds (a2-4) may be used alone or in combination of two or more.

[0112] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-4) may be 0 mol to 80 mol, preferably 5 mol to 70 mol, and more preferably 10 mol to 60 mol.

[0113] Diamine compound (a2-5)

[0114] The diamine compound (a2-5) of the present invention is a diamine compound represented by the following formula (A25).

[0115] H 2 NA 1 -Y 11 -L 1 -Y 11 -A 2 -NH 2 (A25)

[0116] In formula (A25), A 1 and A 2 Each independently represents a substituted or unsubstituted divalent aromatic ring group; Y 11 represents -O-, -S-, -COO- or -OCO-; L 1 It represents the structure represented by the following formula (L1-1).

[0117]

[0118] In formula (L1-1), K 1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; h is an integer from 0 to 4. When h is an integer from 2 to 4, K 1 Each independently has the above definition; j is an integer from 1 to 3, when j is 2 or 3, K 1 and h each independently have the above definitions, and “*” represents a bonding position.

[0119] In other words, the diamine compound (a2-5) of the present invention is a diamine compound represented by the following formula (A25′).

[0120]

[0121] In formula (A25'), A 1 , A 2 and Y 11 The definitions of are the same as those in formula (A25), and K 1 The definitions of h and j are the same as those in formula (L1-1).

[0122] In formula (A25) and formula (A25'), A1 and A 2 Each independently represents a substituted or unsubstituted divalent aromatic ring group, wherein the aforementioned divalent aromatic ring group is a group formed by removing two hydrogen atoms from the ring part of the aromatic ring, and the ring part may have a substituent. Examples of the aromatic ring include aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, biphenyl ring, etc.; nitrogen-containing heterocyclic rings such as pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, etc. The substituents that the aromatic ring may have include, for example, alkyl groups having 1 to 6 carbon atoms. In A 1 With A 2 In the same case, the diamine compound (a2-5) can be easily synthesized, and the liquid crystal alignment film formed by including the liquid crystal alignment agent can more effectively reduce the AC image sticking of the liquid crystal display element. 1 and A 2 In terms of further reducing AC image sticking in a liquid crystal display element, a group formed by removing two hydrogen atoms from a ring portion of a benzene ring, a biphenyl ring, a pyridine ring or a pyrimidine ring which may have a substituent is preferred.

[0123] In some embodiments, in the above formula (A25) and formula (A25'), A 1 and A 2 Each independently represents a substituted or unsubstituted 1,4-phenylene group. 1 and A 2 When each independently represents a substituted or unsubstituted 1,4-phenylene group, a liquid crystal alignment film formed by including a liquid crystal alignment agent can more effectively reduce AC image sticking of a liquid crystal display element.

[0124] In formula (A25), in formula (L1-1) and formula (A25'), K 1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms, and when h is an integer of 2 to 4, K 1 Each may be the same or different.

[0125] K in formula (A25) 1 In the above, the alkyl group with 1 to 6 carbon atoms may be linear or branched. In some specific examples, the alkyl group with 1 to 6 carbon atoms may include but is not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, etc.

[0126] K in formula (A25) 1In the above, the alkoxy group having 1 to 6 carbon atoms may include, but is not limited to, groups listed as the alkyl group having 1 to 6 carbon atoms bonded to an oxygen atom, and specifically, may include, for example, a methoxy group, an ethoxy group, and the like.

[0127] K in formula (A25) 1 In the above, the fluoroalkyl group having 1 to 6 carbon atoms may include, but is not limited to, groups obtained by replacing at least one hydrogen atom of the groups listed as the alkyl group having 1 to 6 carbon atoms with a fluorine atom.

[0128] When the diamine component (a2) includes the diamine compound (a2-5) represented by the formula (A25), the liquid crystal alignment film formed therefrom can effectively reduce the AC image sticking of the liquid crystal display element.

[0129] In one embodiment, when the diamine compound (a2-5) represented by formula (A25) has a structure represented by formula (A25-1), the liquid crystal alignment film formed by including the liquid crystal alignment agent can further reduce the AC image sticking of the liquid crystal display element.

[0130]

[0131] In formula (A25-1), A 1 , A 2 and Y 11 The definitions of are the same as those in formula (A25), and K 1 The definitions of , h and j are the same as those in formula (L1-1) and are not further elaborated here.

[0132] In the above formula (A25-1), h is an integer from 0 to 4, preferably an integer from 0 to 2, and more preferably 0.

[0133] In the above formula (A25-1), j is an integer from 1 to 3, preferably 1.

[0134] More preferably, the diamine compound (a2-5) represented by formula (A25) is a structure represented by the following formula (A25-2). In this case, in a liquid crystal display element having a liquid crystal alignment film, it is easy to cause interaction with the benzene rings possessed by the liquid crystal molecules, which can further reduce the AC image sticking of the liquid crystal display element.

[0135]

[0136] In formula (A25-2), Y 11 The definition of Y in formula (A25) 11 Same, K 1 The definitions of h and j are the same as those of K in formula (L1-1) 1 , h and j are the same and will not be described in detail here.

[0137] In formula (A25-2), K 2 Each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms. Each r independently represents an integer from 0 to 5, preferably 0. When r represents an integer from 2 to 5, K 2 Each independently has the above definition. n is an integer from 1 to 3. When n is 2 or 3, K 1 and h each independently have the above definition.

[0138] The phenyl group connected to the amino group in the above formula (A25-2) is preferably a substituted or unsubstituted 1,4-phenylene group. The liquid crystal alignment film formed by including the liquid crystal alignment agent can more effectively reduce the AC image sticking of the liquid crystal display element.

[0139] Specific examples of diamine compounds (a2-5) may include but are not limited to compounds shown in the following formulas (A25-3) to (A25-11), preferably compounds shown in formula (A25-3), compounds shown in formula (A25-4), compounds shown in formula (A25-10) and compounds shown in formula (A25-11).

[0140]

[0141] The diamine compound (a2-5) represented by the above formula (A25) or formula (A25′) can be produced by a common method of organic chemistry. The production method of the diamine compound (a2-5) is listed and described below, but the present invention is not limited thereto.

[0142] Specifically, Y 11 is O or S, j is 1, and A 1 With A 2 In the case of the same nitrobenzene derivative, as shown in the following reaction formula (1) or reaction formula (2), the intermediate product "dinitro compound" can be obtained by using a commercially available nitrobenzene derivative substituted with a leaving group (X) to react with a dihydroxycyclohexane derivative or a dithiolcyclohexane derivative. The leaving group (X) is preferably a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a p-toluenesulfonyl group (-OTs) and a methanesulfonyl group (-Oms). The following only lists the reaction formula (1) of the reaction of nitrobenzene derivatives with dihydroxycyclohexane derivatives and the reaction formula (2) of the reaction of nitrobenzene derivatives with dithiolcyclohexane derivatives, but this embodiment is not limited thereto. Among them, the nitrobenzene derivative can be substituted with a leaving group (X) according to A 1 With A 2 Depending on the difference, other nitro aromatic derivatives can be used as reaction raw materials, such as nitrobiphenyl derivatives, nitropyridine derivatives, etc.

[0143]

[0144] In reaction formula (1) and reaction formula (2), X is a leaving group; K 1 and h are defined as K in the formula (L1-1) and formula (A25') of the above formula (A25). 1 The definition of K is the same as h; 2 and r is defined as K in the above formula (A25-2) 2 The definitions of and r are the same and will not be repeated here.

[0145] There is no particular limitation on the conduct of reaction formula (1) and reaction formula (2), and they can be conducted in the presence of a base. As long as the target product can be synthesized, the base used is not particularly limited, and examples thereof include inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, sodium hydride, and organic bases such as pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and tributylamine. Depending on the situation, when a palladium catalyst or a copper catalyst or a copper catalyst is used in combination, the yield can be increased. Specific examples of palladium catalysts include, but are not limited to, Bis(dibenzylideneacetone)palladium, Tris(dibenzylideneacetone)dipalladium, 1,1'-Bis(diphenylphosphino)ferrocene]dichloropalladium(II), etc. The above reaction solvent can be selected from polar aprotic solvents such as acetonitrile, dimethylformamide (DMF), acetone, and dimethylacetamide (DMAc). From the perspective of easy synthesis, the base is preferably potassium carbonate.

[0146] The reaction temperature of reaction formula (1) or reaction formula (2) can be appropriately set according to the reaction method, preferably -20°C to 200°C, more preferably 0°C to 150°C.

[0147] Next, as shown in the following reaction formula (3), the nitro group in the product of reaction formula (1) (i.e., the intermediate product "dinitro compound") is converted into an amine group by a reduction method to obtain the final product "diamine compound". The following is only an example, but the present invention is not limited thereto.

[0148]

[0149] Similarly, as shown in the following reaction formula (4), the nitro group in the product of reaction formula (2) (i.e., the intermediate product "dinitro compound") can also be converted into an amine group by a reduction method to obtain the final product "diamine compound". The following is only an example, but the present invention is not limited thereto.

[0150]

[0151] The reduction method of the dinitro compound is not particularly limited. For example, palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, carbon-supported platinum sulfide catalyst (PtS / C catalysts, Platinumsulfided on carbon) and the like can be used as catalysts, and the reduction is carried out by hydrogen, hydrazine and hydrogen chloride in solvents such as ethyl acetate, toluene, tetrahydrofuran, dioxane and alcohols. An autoclave can also be used as needed to carry out the reduction reaction under pressure. On the other hand, when the substituent structure of the hydrogen atom of the substituted benzene ring or saturated hydrocarbon group contains an unsaturated bond, when palladium carbon or platinum carbon is used, the unsaturated bond may be reduced to a saturated bond. Therefore, it is preferred to use a transition metal such as reduced iron, tin, tin chloride as a catalyst for the reduction condition.

[0152] The reaction temperature of reaction formula (3) and reaction formula (4) can be appropriately set according to the reaction method, preferably -20°C to 200°C, more preferably 0°C to 150°C.

[0153] When j is 2 or 3, the compound represented by the following formula (1-1) or formula (2-1) can be used to replace the dihydroxycyclohexane derivative and the dithiolcyclohexane derivative, respectively, to obtain the compound represented by the above formula (A25) (where Y 11 is O or S, and j is 2 or 3).

[0154]

[0155]

[0156] In formula (1-1) and formula (2-1), k is 0 or 1; K 1 and h are defined as K in the formula (L1-1) and formula (A25') of the above formula (A25). 1 The definition of and h is the same.

[0157] On the other hand, when Y 11 When Y is *-COO- or *-OCO- (wherein the bonding position of "*" is linked to the amine aromatic group), the diamine compound can be appropriately synthesized using a known method. 11When it is a diamine compound of *-COO-, it can be obtained by esterification of a dihydroxycyclohexane derivative (e.g., 1,4-cyclohexanediol) and a nitroaromatic formyl chloride derivative (e.g., nitrobenzoyl chloride), followed by reduction of the nitro group. 11 In the case of a diamine compound of *-OCO-, it can be obtained by subjecting a cyclohexanediacyl chloride derivative to an esterification reaction with a nitroaromatic phenol derivative (for example, nitrophenol), followed by reduction of the nitro group.

[0158] On the other hand, when A 1 and A 2 When Y is a different substituted divalent aromatic ring group, the diamine compound can be appropriately synthesized using a known method. 11 For example, a compound in which n is O or S and n is 1 is used as an example, a commercially available hydroxyl-nitro aromatic derivative is first reacted with a cyclohexane derivative having two leaving groups (X) to obtain a nitro compound containing one leaving group (X). The nitro compound containing one leaving group is then reacted with another hydroxyl-nitro aromatic derivative to obtain a dinitro compound, and then the nitro group is reduced to obtain a diamine compound.

[0159] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-5) may be 0 mol to 30 mol, preferably 5 mol to 25 mol, and more preferably 7 mol to 20 mol.

[0160] Other diamine compounds (a2-6)

[0161] In addition to the aforementioned diamine compound (a2-1) as represented by formula (A21), the diamine compound (a2-2) as represented by formula (A22), the diamine compound (a2-3), the diamine compound (a2-4) and the diamine compound (a2-5), the diamine component (a2) for obtaining the polymer (A) may selectively include other diamine compounds (a2-6). For example, the other diamine compound (a2-6) may include but is not limited to: 4,4′-diaminoazobenzene or diamine compounds represented by the following formulas (A26-1) to (A26-3) and other diamine compounds having a photo-alignment group; 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol or 4,6-diaminoresorcinol; 2,4- Diamine compounds having a carboxyl group, such as diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid or diamine compounds represented by the following formula (A26-4) to (A26-7); 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ketone, 1,4-bis(4-aminobenzyl)benzene, 4,4′-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine or 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamine compounds having a urea bond such as diamine compounds represented by the following formulas (A26-8) to (A26-10); diamine compounds having an amide bond such as diamine compounds represented by the following formulas (A26-11) to (A26-13); diamine compounds having a photopolymerizable group at the end such as methacrylate 2-(2,4-diaminophenoxy)ethyl or 2,4-diamino-N,N-diallylaniline; diamines having a siloxane bond, such as 3-bis(3-aminopropyl)-tetramethyldisiloxane; diamine compounds having a siloxane bond such as diamine compounds represented by the following formulas (A26-14) to (A26-15) A diamine compound with an oxazoline structure.

[0162]

[0163]

[0164]

[0165] In formula (A26-4), Y5 1 Represents a single bond, -CH 2 -、-C 2 H 4 -、-C(CH 3 ) 2 -、-CF 2 -、-C(CF 3 )2 -、-O-、-CO-、-NH-、-N(CH 3 )-、-CONH-、-NHCO-、-CH 2 O-、-OCH 2 -、-COO-、-OCO-、-CON(CH 3 )-or-N(CH 3 )CO-; m1 and m2 each independently represent an integer from 0 to 4, and (m1+m2) represents an integer from 1 to 4. In formula (A26-5), m3 and m4 each independently represent an integer from 1 to 5. In formula (A26-6), Y 52 represents a linear or branched alkyl group having 1 to 5 carbon atoms; m5 represents an integer from 1 to 5. In formula (A26-7), Y 53 and Y 54 Each independently represents a single bond, -CH 2 -、-C 2 H 4 -、-C(CH 3 ) 2 -、-CF 2 -、-C(CF 3 ) 2 -、-O-、-CO-、-NH-、-N(CH 3 )-、-CONH-、-NHCO-、-CH 2 O-、-OCH 2 -、-COO-、-OCO-、-CON(CH 3 )-or-N(CH 3 )CO-; m6 represents an integer from 1 to 4.

[0166] The above-mentioned other diamine compounds (a2-6) may be used alone or in combination of plural types.

[0167] Based on the total usage of the diamine component (a2) being 100 mol, the usage of the other diamine compounds (a2-6) may be 0 mol to 80 mol, preferably 5 mol to 70 mol, and more preferably 10 mol to 60 mol.

[0168] Polymer (B)

[0169] In addition to the aforementioned polymer (A), the liquid crystal alignment agent of the present invention may also selectively contain a polymer (B) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component (b1) and a diamine component (b2), and an imidized polymer (i.e., polyimide) of the polyimide precursor. For example, the polymer (B) may include, but is not limited to, at least one polymer selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component (b1) and a diamine component (b2) that does not contain the above-mentioned specific diamine compound and an imidized product (i.e., polyimide) of the polyimide precursor. Specific examples of the above-mentioned polyimide precursor may include, for example, polyamic acid or polyamic acid ester. The polymer (B) may be used alone or in combination.

[0170] The usage ratio of polymer (A) to polymer (B) (ie, the mass ratio of [polymer (A)] / [polymer (B)]) may be 10 / 90 to 90 / 10, preferably 20 / 80 to 90 / 10, and more preferably 20 / 80 to 80 / 20.

[0171] Tetracarboxylic acid derivative component (b1)

[0172] The tetracarboxylic acid derivative component (b1) used to obtain the polymer (B) may include, for example, but not limited to, a non-cyclic aliphatic tetracarboxylic dianhydride compound, an alicyclic tetracarboxylic dianhydride compound, an aromatic tetracarboxylic dianhydride compound, or derivatives of these compounds. Specific examples of non-cyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, and aromatic tetracarboxylic dianhydride compounds may include, for example, the tetracarboxylic dianhydride compounds exemplified for the aforementioned polymer (A). Preferably, the tetracarboxylic acid derivative component (b1) may include an alicyclic tetracarboxylic dianhydride or its derivative (a1-1) as shown in the above formula (A11), or as shown in the above formula (A12) and X 1 ' represents a tetracarboxylic dianhydride compound or a derivative thereof having a structure represented by formula (A12-1) to formula (A12-6). The tetracarboxylic acid derivative component (b1) can be used alone or in combination of plural kinds.

[0173] The tetracarboxylic acid derivative component (b1) preferably comprises a tetracarboxylic acid derivative as shown in the above formula (A12) and X 1 ' represents a tetracarboxylic dianhydride compound having a structure represented by the following formula (A12-33) (hereinafter referred to as a tetracarboxylic dianhydride compound (b1-1)).

[0174]

[0175] In the formula (A12-33), Z11 represents a single bond; and "*" represents a bonding position.

[0176] The aforementioned tetracarboxylic dianhydride compound (b1-1) may be used alone or in combination of two or more.

[0177] More preferably, the tetracarboxylic acid derivative component (b1) comprises a tetracarboxylic dianhydride compound represented by the following formula (B11).

[0178]

[0179] Based on 100 mol of the total usage of the tetracarboxylic acid derivative component (b1), the usage of the tetracarboxylic dianhydride compound (b1-1) may be 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0180] Diamine component (b2)

[0181] The diamine component (b2) used to obtain the polymer (B) may, for example, include but is not limited to the aforementioned diamine component (a2), or a diamine compound having at least one nitrogen-containing atom structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amine group and a tertiary amine group (hereinafter referred to as diamine compound (b2-1)), but the diamine component (b2) does not include the aforementioned diamine compound (a2-1).

[0182] The diamine component (b2) can be used alone or in combination of two or more.

[0183] Diamine compound (b2-1)

[0184] The diamine compound (b2-1) having the above-mentioned specific nitrogen-containing atom structure may have a nitrogen-containing heterocyclic ring, for example, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, tantalum, Pyridine Indole, benzimidazole, purine, quinoline, isoquinoline, Pyridine, quinone Linole three Carbazole, acridine, piperidine, piperidine Pyrrolidine or hexamethyleneimine, etc. Among them, pyridine, pyrimidine, pyrrolidine Piperidine, piperidine, quinoline, carbazole or acridine is preferred.

[0185] The diamine compound (b2-1) having the above-mentioned specific nitrogen atom-containing structure may include a secondary amine group and a tertiary amine group as represented by the following formula (B21).

[0186]

[0187] In formula (B21), Z represents a hydrogen atom or an alkyl group, a cycloalkyl group or an aryl group having 1 to 10 carbon atoms; "*" represents the bonding position of the hydrocarbon group.

[0188] The alkyl represented by Z may include, but not limited to, methyl, ethyl or propyl; the cycloalkyl represented by Z may include, but not limited to, cyclohexyl; the aryl represented by Z may include, but not limited to, phenyl or tolyl. Z is preferably a hydrogen atom or a methyl group.

[0189] Specific examples of diamine compounds (b2-1) having the above-mentioned specific nitrogen-containing atom structure may include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperidin, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamine compounds shown in the following formulas (B21-1) to (B21-8), or diamine compounds shown in the following formulas (B21-9) to (B21-26).

[0190]

[0191]

[0192]

[0193]

[0194] The diamine compound (b2-1) may be used alone or in combination of two or more.

[0195] Based on 100 mol of the total usage of the diamine component (b2), the usage of the diamine compound (b2-1) may be 15 mol to 100 mol, preferably 20 mol to 90 mol, and more preferably 25 mol to 80 mol.

[0196] Method for making polymer

[0197] The manufacture of polymer (A) or polymer (B) can be carried out by reacting the aforementioned diamine component and tetracarboxylic acid derivative component in a solvent (condensation polymerization). When a part of polymer (A) or polymer (B) has an amic acid structure, for example, by reacting the tetracarboxylic acid derivative component with the diamine component, a polymer (i.e., polyamic acid) having an amic acid structure is obtained. The aforementioned solvent is not particularly limited, and it only needs to be able to dissolve the formed polymer. For example, a specific example of the solvent may include but is not limited to N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone. In some specific examples, when the solvent solubility of the polymer is high, the solvent may include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent as shown in the following formula (D-1) to formula (D-3). In formula (D-1), Z 1 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-2), Z 2 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-3), Z 3 The substituent represents an alkyl group having 1 to 4 carbon atoms.

[0198]

[0199] The aforementioned solvents can be used alone or in combination. Secondly, even if the solvent is insoluble in the polymer, it can still be mixed with the above-mentioned solvent within the range that the generated polymer will not precipitate. When the diamine component and the tetracarboxylic acid derivative component react in the solvent, the reaction can be carried out at any concentration, but preferably 1wt% to 50wt%, and more preferably 5wt% to 30wt%. The reaction can also be carried out at a high concentration initially, and then additional solvent is added. When reacting, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid derivative component is preferably 0.8 to 1.2. Similar to the general polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the polymer (A) or polymer (B) formed.

[0200] The polymer having an amide ester structure can be obtained, for example, by the following known methods: (1) a method in which the polyamide acid obtained by the above method is further reacted with an esterifying agent, (2) a method in which a tetracarboxylic acid diester compound is reacted with a diamine compound, or (3) a method in which a tetracarboxylic acid diester dihalide is reacted with a diamine compound.

[0201] The imide compound in the polymer (A) or polymer (B) contained in the liquid crystal alignment agent of the present invention can be obtained, for example, by subjecting the polymer obtained above to a dead cycle. In the imide compound, the dead cycle rate (also referred to as the imidization rate) of the functional group possessed by the amic acid group or its derivative is not necessarily 100%, and the imidization rate can be arbitrarily adjusted according to the use and / or purpose.

[0202] The method for obtaining the imide product may be, for example, thermal imidization in which the polymer solution obtained by the above reaction is directly heated, or catalytic imidization in which a catalyst is added to the polymer solution. When thermal imidization is performed in the solution, the temperature is preferably 100° C. to 400° C., and more preferably 120° C. to 250° C. When thermal imidization is performed, it is preferred to discharge the water generated by the imidization reaction out of the system.

[0203] The aforementioned catalytic imidization can be carried out, for example, by adding an alkaline catalyst and anhydride to the polymer solution obtained by the reaction, preferably at -20°C to 250°C, and more preferably at 0°C to 180°C for stirring. The amount of alkaline catalyst added is preferably 0.5 to 30 moles of the amide acid group, and more preferably 2 to 20 moles; the amount of anhydride added is preferably 1 to 50 moles of the amide acid group, and more preferably 3 to 30 moles. Specific examples of alkaline catalysts may include but are not limited to pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is more ideal because it has a moderate alkalinity that allows the reaction to proceed. Specific examples of anhydrides may include but are not limited to acetic anhydride, trimellitic anhydride or benzene tetracarboxylic anhydride. Among them, if acetic anhydride is used, purification after the reaction is easier, so it is more ideal. The imidization rate of the catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature and / or reaction time. When the imide formed is recovered from the reaction solution of the above-mentioned imidization, the reaction solution is put into a solvent and precipitated. The solvent used for precipitation may include, but is not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene or water. After filtering and recovering the polymer precipitated by the solvent, it can be dried at normal pressure or reduced pressure, at room temperature or by heating. Alternatively, the polymer recovered by precipitation is dissolved in a solvent again, and reprecipitation is carried out for recovery, and this operation is repeated 2 to 10 times to reduce impurities in the polymer. The solvent used may be, for example, alcohols or ketone hydrocarbons. If used in three or more solvents selected therein, the efficiency of refining can be further improved, so it is more ideal.

[0204] When the polymer solution is prepared into a solution with a concentration of 10wt% to 15wt%, the solution concentration of the polymer (A) or polymer (B) of the present invention is not particularly limited. Based on the viewpoint of easier operation, the solution concentration can be, for example, 10mPa·s to 1000mPa·s. The solution viscosity (mPa·s) of the polymer is a value measured at 25°C using a good solvent for the polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone, etc.) to prepare a polymer solution with a concentration of 10wt% to 15wt%.

[0205] The weight average molecular weight (Mw) of the polymer (A) or polymer (B) of the present invention measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 2,000 to 500,000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, and more preferably 10 or less. When the molecular weight of the polymer is within the above molecular weight range, it can ensure good orientation and stability of the liquid crystal display element.

[0206] When synthesizing the polymer (A) or polymer (B) of the present invention, the tetracarboxylic acid derivative component and the diamine component as described above can be used, and a suitable end-capping agent can be used to synthesize a terminal-sealed polymer. The terminal-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by the coating, and improving the sealing properties of the sealant and the liquid crystal alignment film. The end of the polymer (A) or polymer (B) of the present invention may, for example, contain an amine group, a carboxyl group, an anhydride group or a derivative thereof. An amine group, a carboxyl group, an anhydride group or a derivative thereof can be obtained by a general condensation reaction, or by using an end-capping agent described later to seal the end. Similarly, the aforementioned derivatives can be obtained, for example, using the following end-capping agent.

[0207] For example, the end-capping agent may include, but is not limited to, acetic anhydride, maleic anhydride, neddic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-((3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione or 4-ethynylphthalic anhydride; dibutyl dicarbonate or diallyl dicarbonate; Carbonic acid diester compounds; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride or nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine or n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate or naphthyl isocyanate, etc.

[0208] The blocking agents may be used alone or in combination of two or more.

[0209] Based on 100 mol parts of the total usage of the diamine component, the usage of the end-capping agent is preferably 0.01 mol parts to 20 mol parts, and more preferably 0.01 mol parts to 10 mol parts.

[0210] Other components in the liquid crystal alignment agent The liquid crystal alignment agent of the present invention may include a polymer (A) and a polymer (B) added as needed. In addition to the polymer (A) and the polymer (B), the liquid crystal alignment agent of the present invention may selectively include other polymers. The types of other polymers may include, for example, but are not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates.

[0211] Solvent (C)

[0212] Based on the viewpoint of forming a uniform film, the liquid crystal aligning agent takes the form of a coating liquid to make a liquid crystal aligning film. The liquid crystal aligning agent of the present invention is preferably a coating liquid containing the above-mentioned polymer component and an organic solvent (hereinafter referred to as solvent (C)). Among them, based on the set coating thickness to be formed, the polymer concentration in the liquid crystal aligning agent can be appropriately changed. Based on the viewpoint of forming a uniform and defect-free coating, the polymer concentration in the liquid crystal aligning agent is preferably more than 1wt%. Based on the viewpoint of the storage stability of the solution, the polymer concentration in the liquid crystal aligning agent is preferably less than 10wt%. The ideal polymer concentration can be 2wt% to 8wt%. The content of polymer (A) in the liquid crystal aligning agent can be appropriately changed by the coating method of the liquid crystal aligning agent and / or the film thickness of the desired liquid crystal aligning film, which is preferably 2wt% to 10wt%, and more preferably 3wt% to 7wt%. There is no particular restriction on the organic solvent contained in the liquid crystal aligning agent, and it only needs to be able to uniformly dissolve the aforementioned polymer. Specific examples thereof may include, but are not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone, etc., and the aforementioned organic solvents are also called good solvents. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide or γ-butyrolactone is preferred. Based on 100 wt % of the total amount of the solvent in the liquid crystal alignment agent, the amount of the good solvent may be 20 wt % to 99 wt %, preferably 20 wt % to 90 wt %, and more preferably 30 wt % to 80 wt %.

[0213] Secondly, the organic solvent in the liquid crystal alignment agent is preferably a mixed solvent of the aforementioned solvent and a solvent (also referred to as a poor solvent) that can improve the coating property of the liquid crystal alignment agent and the surface smoothness of the coating film. The specific poor solvent used in combination may be, for example, but not limited to, the solvent described below. Based on the total amount of solvent used in the liquid crystal alignment agent being 100wt%, the amount of the poor solvent used is preferably 1wt% to 80wt%, more preferably 10wt% to 80wt%, and particularly preferably 20wt% to 70wt%. The type and amount of the poor solvent used can be appropriately selected according to the coating device, coating conditions and / or coating environment of the liquid crystal alignment agent. For example, the poor solvent may be, for example, diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethyl carbonate, ethylene glycol monobutyl ether (butyl cellulose), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy) )-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isopentyl lactate, diethylene glycol monoethyl ether, or diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0214] Among them, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone is preferred.

[0215] The solvent combination of the good solvent and the poor solvent can be preferably, for example, but not limited to, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyl lactamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethyl Glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-Hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol diacetate alcohol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl carbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; or N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide and diisobutyl ketone, etc.

[0216] The aforementioned solvent (C) may be used alone or in combination of two or more.

[0217] Based on 100 parts by weight of the total amount of polymer (A) and polymer (B), the amount of solvent (C) is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

[0218] additive

[0219] The liquid crystal alignment agent of the present invention may also selectively add components other than the polymer component and the organic solvent (hereinafter referred to as additive components). These additive components may include, for example, but are not limited to: a bonding aid for improving the adhesion between the liquid crystal alignment film and the substrate or the adhesion between the liquid crystal alignment film and the sealant, a compound for improving the strength of the liquid crystal alignment film (hereinafter referred to as a cross-linking compound), a compound for promoting imidization, a dielectric or conductive material for adjusting the dielectric constant or resistance of the liquid crystal alignment film, etc.

[0220] The aforementioned adhesion aid may be, for example, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl diethoxymethyl silane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane, 3-ureidopropyl trimethoxysilane, 3-ureidopropyl triethoxysilane, N-ethoxycarbonyl-3-aminopropyl trimethoxysilane, N-ethoxycarbonyl-3-aminopropyl triethoxysilane, N-triethoxysilylpropyl triethyl triamine, N-trimethoxysilylpropyl triethyl triamine, vinyl triamine Silane coupling agents such as methoxysilane, vinyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-glycidoxypropyl methyl dimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, tris(3-trimethoxysilylpropyl) isocyanurate, or 3-isocyanate propyl triethoxysilane. When using an adhesion aid, from the viewpoint of exhibiting good resistance to AC sticking, the amount of the adhesion aid used is preferably 0.1 to 30 parts by weight, and more preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the total amount of the polymer used in the liquid crystal aligning agent.

[0221] Cross-linking compound For the aforementioned cross-linking compound, based on the viewpoint of exhibiting good resistance to AC image sticking and effectively improving film strength, it can be a compound having an ethylene oxide group, a propylene oxide group, at least one group selected from the group consisting of a group represented by the following formula (E1) and a group represented by the following formula (E2), or a compound selected from the compound represented by the following formula (E3).

[0222]

[0223] In formula (E1), G 1 and G 2 Each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH 2 -OH. In formula (E2), G 3 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. 4 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. 5 It represents a (g1+g2)-valent organic group containing an aromatic ring. 6 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. g1 represents an integer from 1 to 6, and g2 represents an integer from 0 to 4. In formula (E3), G 5 The (g1+g2)-valent organic group with an aromatic ring represented by the compound may be a (gl+g2)-valent aromatic hydrocarbon group with a carbon number of 6 to 30, an aromatic hydrocarbon group with a carbon number of 6 to 30 directly or through a linking group to form a (g1+g2)-valent organic group, or a (g1+g2)-valent group with an aromatic heterocycle. The aromatic hydrocarbon may be, for example, benzene or naphthalene. The aromatic heterocycle may be exemplified by the aromatic heterocycles of the above-mentioned specific nitrogen-containing atom structure. The linking group may be an alkylene group with a carbon number of 1 to 10 or a group that removes a hydrogen atom from the alkylene group, or a divalent or trivalent cyclohexane group. Among them, any hydrogen atom of the alkylene group may also be substituted by an organic group such as a fluorine atom or a trifluoromethyl group. In formula (E3), G 6 The alkyl group having 1 to 5 carbon atoms represented by the group may be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl or n-pentyl.

[0224] Compounds with ethylene oxide

[0225] Specific examples of compounds having an ethylene oxide group include N,N,N′,N′-tetraepoxypropyl-m-xylene diamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N′,N′-tetraepoxypropyl-4,4′-diaminodiphenylmethane, N,N,N′,N′-tetraepoxypropyl-p-phenylenediamine, and compounds containing nitrogen atoms such as those shown in the following formulas (E4) to (E6).

[0226]

[0227]

[0228] Compounds having propylene oxide groups

[0229] Specific examples of the compound having an propylene oxide group include compounds represented by the following formula (E7) to formula (E16).

[0230]

[0231]

[0232]

[0233] In formula (E15), R represents The “*” represents the bonding position.

[0234] Compounds having a group represented by formula (E1)

[0235] Specific examples of the compound having a group represented by the formula (E1) include compounds represented by the following formulas (E1-1) to (E1-12).

[0236]

[0237]

[0238]

[0239] Compounds having a group represented by formula (E2)

[0240] Specific examples of the compound having a group represented by formula (E2) include compounds represented by the following formulas (E2-1) to (E2-4).

[0241]

[0242] Compounds having a group represented by formula (E3)

[0243] Specific examples of the compound having a group represented by formula (E3) include compounds represented by the following formulas (E3-1) to (E3-10).

[0244]

[0245]

[0246] In the liquid crystal alignment agent of the present invention, based on the total amount of the polymer in the liquid crystal alignment agent being 100 parts by weight, the amount of the cross-linking compound used is preferably 0.5 to 20 parts by weight. In particular, based on the viewpoint of the cross-linking reaction and the good resistance to AC residual image, the amount of the cross-linking compound used is more preferably 1 to 15 parts by weight.

[0247] Compounds that promote imidization

[0248] The aforementioned compound for promoting imidization is preferably a compound having a basic site (for example: a primary amine group, an aliphatic heterocycle (such as a pyrrolidine skeleton), an aromatic heterocycle (such as an imidazole ring or an indole ring), or a guanidine group, etc.) (except for the above-mentioned cross-linking compound and the close-fitting aid), or a compound that produces the basic site when calcined. More preferably, the compound that promotes imidization is a compound that produces the basic site when calcined, and a specific example thereof may be an amino acid in which a part or all of the basic sites possessed by the amino acid are protected. Specific examples of the above-mentioned amino acids include glycine, alanine, cysteine, methionine, asparagine, glutamic acid, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. For the purpose of promoting the imidization compound, a more preferable specific example is N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0249] The liquid crystal alignment film of the present invention is obtained from the aforementioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or vertical alignment type (VA type) liquid crystal alignment film, and it is a liquid crystal alignment film suitable for horizontal alignment type liquid crystal display elements such as IPS mode or FFS mode. The liquid crystal display element of the present invention has the above-mentioned liquid crystal alignment film. The liquid crystal display element of the present invention can be prepared, for example, by the following steps (1) to step (4) or steps (1) to step (2) and step (4).

[0250] Step (1): Applying a liquid crystal alignment agent on a substrate

[0251] The liquid crystal alignment agent of the present invention is applied on one side of a substrate provided with a patterned transparent conductive film by using an appropriate coating method such as roller coating, spin coating, printing or inkjet. There is no particular limitation on the substrate, which only needs to be a highly transparent substrate. A glass substrate or a silicon nitride substrate can also be used in combination with a plastic substrate such as an acrylic substrate or a polycarbonate substrate. Secondly, in a reflective liquid crystal display element, if only a single-sided substrate is used, an opaque object such as a silicon wafer can also be used, and the electrode used can also be a light-reflecting material such as aluminum. Furthermore, when making an IPS-type or FFS-type liquid crystal component, a comb-tooth type uses an electrode substrate composed of a patterned transparent conductive film or metal film and an opposing substrate without an electrode.

[0252] Examples of methods for coating a liquid crystal aligning agent on a substrate to form a film include screen printing, lithography, flexographic printing, inkjet printing, spray coating, etc. Among them, the film forming method is preferably coating by an inkjet method.

[0253] Step (2): Calcination of the coated liquid crystal alignment agent Step (2) is a step of calcining the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating means such as a hot plate, a heat circulation oven or an IR (infrared) oven, or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and calcining steps performed after the liquid crystal alignment agent of the present invention has been coated can select any temperature and time, and multiple drying or calcining steps can be performed. The drying temperature can be, for example, 40°C to 180°C. From the perspective of shortening the process, it can be performed at 40°C to 150°C. The drying time is not particularly limited, and it can be, for example, 1 minute to 10 minutes or 1 minute to 5 minutes. When thermal imidization of polyamic acid or polyamic acid ester is performed, after the aforementioned drying step, a calcination step can be further performed at a temperature of, for example, 150°C to 300°C or 150°C to 250°C. The calcination time is not particularly limited, and may be 5 to 40 minutes or 5 to 30 minutes. If the film after calcination is too thin, the reliability of the liquid crystal display element will be reduced, so the film thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm.

[0254] Step (3): Orienting the film obtained in step (2) Step (3) is to orient the film obtained in step (2) as appropriate. In other words, in a horizontally oriented liquid crystal display element such as an IPS mode or an FFS mode, the coating is subjected to an orientation treatment to impart an orientation capability. On the other hand, in a vertically oriented liquid crystal display element such as a VA mode or a PSA mode, the formed coating can be used directly as a liquid crystal orientation film, but the coating can also be subjected to an orientation treatment to impart an orientation capability. The orientation treatment of the liquid crystal orientation film can be listed as a friction treatment method or a photo-orientation treatment method, and the photo-orientation treatment method is preferably used. The photo-orientation treatment method can be listed as a method of irradiating the surface of the above-mentioned film-like object with radiation that has been deflected in a certain direction, and preferably heating it at a temperature of 150°C to 250°C as appropriate to impart liquid crystal orientation (also referred to as liquid crystal orientation capability). The radiation can use ultraviolet rays or visible light with a wavelength of 100nm to 800nm. Among them, the radiation is preferably ultraviolet light having a wavelength of 100 nm to 400 nm, and more preferably ultraviolet light having a wavelength of 200 nm to 400 nm.

[0255] The radiation dose can be 1mJ / cm 2 Up to 10,000mJ / cm 2 , preferably 100mJ / cm 2 Up to 5,000mJ / cm 2 , preferably 100 mJ / cm 2 Up to 1500mJ / cm 2 , and preferably 100 mJ / cm 2 Up to 1000mJ / cm 2 When using a general liquid crystal alignment agent, the light exposure for the alignment treatment is 100mJ / cm 2 Up to 5000mJ / cm 2 However, the liquid crystal orientation agent of the present invention can obtain a liquid crystal orientation film in which the variation (non-uniformity) of the liquid crystal orientation within the film surface is effectively suppressed even if the amount of light irradiation in the orientation treatment is reduced. When irradiating radiation, in order to improve the liquid crystal orientation, the substrate of the aforementioned film-like object can be heated at 50°C to 250°C while irradiating. The liquid crystal orientation film produced in this way can stably orient the liquid crystal molecules in a certain direction. Secondly, the liquid crystal orientation film that has been irradiated with polarized radiation in the aforementioned method can be contact-treated with a solvent, or the liquid crystal orientation film that has been irradiated with radiation can be heat-treated.

[0256] The solvent used in the above-mentioned contact treatment is not particularly limited, and it only needs to be able to dissolve the decomposition products generated from the film after irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellulose, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. Among them, based on the viewpoint of versatility and safety, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate are preferred, and water, 1-methoxy-2-propanol or ethyl lactate are more preferred. The solvent can be used alone or in combination. The temperature for heating the above-mentioned coating film irradiated with radiation is preferably 50°C to 300°C, and more preferably 120°C to 250°C. The heating treatment time is preferably 1 minute to 30 minutes.

[0257] Step (4): Preparation of liquid crystal cells Prepare two liquid crystal alignment film substrates formed as described above, and arrange liquid crystal between the two substrates facing each other. For example, the following two methods can be cited. In the first method, the two substrates are arranged face to face with each other in a manner that the liquid crystal alignment films face each other, separated by a gap (cell gap). Then, the peripheral portions of the two substrates are bonded with a sealant, and then the liquid crystal composition is injected into the cell gap separated by the substrate surface and the sealant, and after it contacts the film surface, the injection hole is sealed.

[0258] The second method is called ODF (One Drop Fil1) method. A sealant such as UV-curable sealant is applied to a predetermined position of one of the two substrates on which a liquid crystal orientation film has been formed, and then a liquid crystal composition is dripped at multiple predetermined positions on the surface of the liquid crystal orientation film. Then, the other substrate is attached in a manner that the liquid crystal orientation film faces each other, and the liquid crystal composition is pushed on the entire surface of the substrate so that it contacts the film surface. Next, ultraviolet light is irradiated on the entire surface of the substrate to harden the sealant. When any of the aforementioned methods is performed, it is preferred to further heat the liquid crystal composition used to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature to remove the flow orientation during liquid crystal filling. Secondly, when the coating is subjected to friction treatment, the two substrates are arranged to face each other at a predetermined angle with the friction directions of each coating, for example, in a manner of orthogonal or antiparallel. The sealant may be, for example, an epoxy resin containing a hardener and aluminum oxide balls as spacers. The liquid crystal composition may include nematic liquid crystals and smectic liquid crystals, and nematic liquid crystals are preferred.

[0259] If necessary, a polarizing plate can be attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. The polarizing plate attached to the outer surface of the liquid crystal cell can be a polarizing film called "H film" which is made of stretched and oriented polyvinyl alcohol and absorbs iodine. It can be a polarizing plate sandwiched by a cellulose acetate protective film, or a polarizing plate composed of the H film itself.

[0260] The following embodiments are used to illustrate the application of the present invention, but they are not used to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. DETAILED DESCRIPTION

[0261] Preparation of diamine component (a2)

[0262] Synthesis Example A2-2

[0263] Synthesis Example A2-2 is a method for synthesizing a compound represented by the above formula (A21-4), which can be prepared by the following method.

[0264] Step 1: 13.9 g (0.1 mole) of reactant A (4-nitrophenol; ) and 26.4 g (0.1 mole) of reactant B (1,4-bis(bromomethyl)benzene; ) was dissolved in 0.3 L of acetonitrile (ACN), and 27.6 g (0.2 mole) of potassium carbonate was added to form a mixture. Then, the mixture was stirred at 77°C for 4 hours, filtered after the reaction, and the filtrate was collected and dried. Then, it was stirred and mixed with 1 L of methanol at 50°C for 1 hour, and the white solid was collected by filtration and drying to obtain the first intermediate product.

[0265] Step 2: 32.2 g (0.1 mole) of the first intermediate product and 21.5 g (0.1 mole) of reactant C (4-nitro-4′-hydroxy biphenyl; ) was dissolved in 1L of ACN, and then 27.6g (0.2mole) of potassium carbonate was added to form a mixture. The mixture was stirred at 79°C for 3 hours and filtered after the reaction. Then, the reaction product was washed with a mixed solution consisting of 500g of water and 150g of methanol at 50°C for 1 hour. Then, it was cooled, filtered, and vacuum dried to obtain the second intermediate product.

[0266] Step 3: Dissolve 45.6 g (0.1 mole) of the second intermediate product in 2.5 L of a mixed solution containing THF and ethanol, and then add 4 g (10 wt%) of palladium-carbon. Then, heat the mixture to 40°C, and then slowly titrate 20.0 g (0.4 mole) of hydrazinium hydroxide. After the titration is completed, heat the mixture to 60°C. After stirring for 3.5 hours, filter and collect the filtrate, and perform reduced pressure filtration and vacuum drying to obtain the diamine compound A2-2 shown in formula (A21-4).

[0267] Synthesis Example A2-1

[0268] Synthesis Example A2-1 is a method for synthesizing a compound as shown in formula (A21-3), which can be prepared by the same method and reactant molar ratio as the compound as shown in formula (A21-4). The difference between the two is that the reactant B used in the compound as shown in formula (A21-3) is 1,4-bis(2-bromoethyl)benzene Therefore, different first intermediate products are obtained With the second intermediate

[0269] Synthesis Example A2-3

[0270] Synthesis Example A2-3 is a method for synthesizing a compound as shown in Formula (A21-5), which can be prepared by the same method and reactant molar ratio as the compound as shown in Formula (A21-4). The difference between the two is that the reactant C used in the compound as shown in Formula (A21-5) is 4-(4-nitrophenoxy)phenol So a different second intermediate product is obtained

[0271] Synthesis Example A2-4

[0272] Synthesis Example A2-4 is a method for synthesizing a compound as shown in Formula (A21-6), which can be prepared using the same method and reactant molar ratio as the compound as shown in Formula (A21-4). The difference between the two is that the reactant B used in the compound as shown in Formula (A21-6) is 4,4'-Bis(bromomethyl)-1,1'-biphenvl( ), so different first intermediate products are obtained and the second intermediate

[0273] Synthesis Example A2-5

[0274] Synthesis Example A2-5 is a method for synthesizing a compound as shown in formula (A21-7), which can be prepared using the same method and reactant molar ratio as the compound as shown in formula (A21-4). The difference between the two is that the reactant B used in the compound as shown in formula (A21-7) is Bis(3-bromomethylphenyl)ether and reactant C is 4-[(4-Nitrophenyl)methyl]phenol Therefore, different first intermediate products are obtained and the second intermediate

[0275] Synthesis Example A2-6

[0276] Synthesis Example A2-6 is a method for synthesizing a compound as shown in Formula (A21-9), which can be prepared using the same method and reactant molar ratio as the compound as shown in Formula (A21-4). The difference between the two is that the reactant A used in the compound as shown in Formula (A21-9) is 4-Nitrobenzoic acid Reactant B is 2,7-Bis(bromomethyl)naphthalene And reactant C is 5-Nitro-2-pyridinecarboxylic acid Therefore, different first intermediate products are obtained and the second intermediate

[0277] Synthesis Example A2-7

[0278] Synthesis Example A2-7 is a method for synthesizing a compound represented by formula (A22-4), which can be synthesized by the method disclosed in an article published on May 17, 2011 in Journal of Molecular Structure, Vol. 994, No. 1-3, pp. 242 to 247.

[0279] Synthesis Example A2-8

[0280] Synthesis Example A2-8 is a method for synthesizing a compound represented by formula (A22-5), which can be synthesized by the method disclosed in an article published on October 5, 2018 in Journal of Molecular Structure, Volume 1169, Pages 46 to 58.

[0281] Synthesis Example A2-9

[0282] Synthesis Example A2-9 is a method for synthesizing a compound represented by formula (A22-6), which can be prepared by the following method.

[0283] Step 1: 13.9 g (0.1 mole) of reactant A (4-nitrophenol; ) and 31.4 g (0.1 mole) of reactant B (2,7-Bis(bromomethyl)naphthalene; ) was dissolved in 0.3 L of acetonitrile (ACN), and 27.6 g (0.2 mol) of potassium carbonate was added to form a mixture. Then, the mixture was stirred at 77° C. for 4 hours, and filtered after the reaction to collect the white precipitate. Then, the white solid was collected by filtration and drying to obtain the first intermediate product.

[0284] Step 2: Dissolve 43.0 g (0.1 mole) of the first intermediate product in 2.5 L of tetrahydrofuran (THF), and then add 4 g (10% by weight) of palladium-carbon to form a mixture. Heat the mixture to 40°C, and then slowly drop 20.0 g (0.4 mole) of hydrazine hydroxide. After the titration is completed, heat to 60°C and stir for 3.5 hours, then filter, collect the filtrate, and perform reduced pressure filtration and vacuum drying to obtain the product.

[0285] Synthesis Example A2-12

[0286] Synthesis Example A2-12 is a method for synthesizing a compound represented by formula (A25-3), which can be prepared by the following method, and the reaction flow is shown in the following reaction flow 1.

[0287] Reaction Scheme 1

[0288]

[0289] Step 1-1: 11.6 g (0.1 mol) of 1,4-cyclohexanediol and 35.3 g (0.25 mol) of 1-fluoro-4-nitrobenzene were dissolved in 0.2 L of DMAc, and 56.1 g (0.4 mol) of potassium carbonate was added to form a mixture. The mixture was stirred at 180° C. for 3 hours, and filtered after the reaction. Then, the reaction product was washed with a mixed solution composed of 200 g of methanol at 50° C. for 1 hour, cooled and filtered, and vacuum dried to obtain intermediate product 1 (dinitro compound).

[0290] Step 1-2: Dissolve 35.8 g (0.1 mol) of the intermediate product 1 in a mixed solution of 1 L of tetrahydrofuran (THF) and ethanol (volume ratio 2.5:1), and then add 7 g (10% by weight) of palladium-carbon. Heat the mixture to 40°C, then slowly titrate 20.0 g (0.4 mol) of hydrazine hydrate. After the titration is completed, heat to 60°C and stir for 3.5 hours, then filter and collect the filtrate and perform reduced pressure filtration and vacuum drying to obtain the product (the compound shown in formula (A25-3)).

[0291] Synthesis Example A2-13

[0292] Synthesis Example A2-13 is a method for synthesizing a compound represented by formula (A25-4), which can be prepared by the following method, and the reaction flow is shown in the following reaction flow 2.

[0293] Reaction Scheme 2

[0294]

[0295] In reaction process 2, the processes and molar numbers of reactants of step 2-1 and step 2-2 are substantially the same as those of step 1-1 and step 1-2, respectively, except that 11.6 g (0.1 mol) of 1,4-cyclohexanediol in step 1-1 is replaced by 13.0 g (0.1 mol) of 2-methyl-1,4-cyclohexanediol having the same molar number.

[0296] Synthesis Example A2-14

[0297] Synthesis Example A2-12 is a method for synthesizing a compound represented by formula (A25-11), which can be prepared by the following method, and the reaction flow is shown in the following reaction flow 3.

[0298] Reaction Scheme 3

[0299]

[0300] In reaction process 3, the processes and molar numbers of reactants in step 3-1 and step 3-2 are substantially the same as those in step 1-1 and step 1-2, respectively, except that 35.3 g (0.25 mol) of 1-fluoro-4-nitrobenzene in step 1-1 is replaced by 35.3 g (0.25 mol) of 1-fluoro-3-nitrobenzene having the same molar number.

[0301] Preparation of polymer (A)

[0302] Synthesis Example A-1-1

[0303] A nitrogen inlet, a stirrer, a condenser and a thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, 2.544 grams (0.006 mol) of the diamine compound (A2-1) shown in formula (A21-3), 1.922 grams (0.006 mol) of the diamine compound (A2-7) shown in formula (A22-4) and 1.946 grams (0.003 mol) of the diamine compound (A2-10) and 80 grams of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) are added, and stirred at room temperature until dissolved. Then, 3.36 grams (0.015 mol) of the compound (A1-1) and 20 grams of NMP are added, and the reaction is carried out at room temperature for 2 hours. After the reaction is completed, the reaction solution is poured into 1500 ml of water to precipitate the polymer, the obtained polymer is filtered, and the steps of washing and filtering are repeated three times with methanol. Afterwards, the product was placed in a vacuum oven and dried at 60° C. to obtain the polymer (A-1-1) of Synthesis Example A-1-1, the formula of which is shown in Table 1.

[0304] Synthesis Examples A-1-2 to A-1-13 and Comparative Synthesis Examples A′-1-1 to A′-1-3

[0305] Synthesis Examples A-1-2 to A-1-13 and Comparative Synthesis Examples A′-1-1 to A′-1-3 use the same preparation method as the method for making the polymer (A-1-1) of Synthesis Example A-1-1, the difference being that Synthesis Examples A-1-2 to A-1-13 and Comparative Synthesis Examples A′-1-1 to A′-1-3 change the type and amount of raw materials in the polymer, and the formula is shown in Table 1 and will not be further described here.

[0306] Synthesis Example A-2-1

[0307] A nitrogen inlet, a stirrer, a condenser and a thermometer were set on a 500 ml four-necked conical flask, and nitrogen was introduced. Then, 2.544 g (0.006 mol) of the diamine compound (A2-1) represented by the formula (A21-3), 1.922 g (0.006 mol) of the diamine compound (A2-7) represented by the formula (A22-4), 1.946 g (0.003 mol) of the diamine compound (A2-10) and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) were added, and stirred at room temperature until dissolved. Next, 3.36 g (0.015 mol) of the compound (A1-1) and 20 g of NMP were added. After reacting at room temperature for 6 hours, 97 g of NMP, 2.55 g of acetic anhydride and 19.75 g of pyridine were added, the temperature was raised to 60°C, and stirring was continued for 2 hours to carry out imidization reaction. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the obtained polymer was filtered, and the washing and filtering with methanol were repeated three times, and placed in a vacuum oven and dried at a temperature of 60°C to obtain a polymer (A-2-1), the formula of which is shown in Table 1.

[0308] Synthesis Example A-2-2

[0309] Synthesis Example A-2-2 uses the same preparation method as the preparation method of the polymer (A-2-1) in Synthesis Example A-2-1, the difference is that Synthesis Example A-2-2 changes the type and amount of raw materials in the polymer. Its formula is shown in Table 1 and is not further described here.

[0310]

[0311]

[0312] Preparation of polymer (B)

[0313] Synthesis Example B-1-1 to Synthesis Example B-1-3

[0314] Synthesis Examples B-1-1 to B-1-3 are prepared using the same method as the method for preparing the polymer (A-1-1) of Synthesis Example A-1-1, except that the types and amounts of raw materials used in the polymers are changed in Synthesis Examples B-1-1 to B-1-3. The formulas are shown in Table 2, and are not described here. Synthesis Examples B-2-1 to B-2-3

[0315] Synthesis Examples B-2-1 to B-2-3 are prepared by the same method as the method for preparing the polymer (A-2-1) of Synthesis Example A-2-1, except that the types and amounts of raw materials used in the polymers are changed in Synthesis Examples B-2-1 to B-2-3. The formulas are shown in Table 2, which are not described in detail here.

[0316] Table 2

[0317]

[0318]

[0319] Preparation of Liquid Crystal Alignment Agent, Liquid Crystal Alignment Film and Liquid Crystal Display Element Example 1

[0320] Weigh 100 parts by weight of the polymer (A-1-1) prepared in Synthesis Example A-1-1, 100 parts by weight of the polymer (B-1-1) prepared in Synthesis Example B-1-1, and 800 parts by weight of NMP (C-1), and stir and mix them at room temperature to obtain the liquid crystal alignment agent of Example 1.

[0321] The liquid crystal alignment agent prepared above is spin-coated on a glass substrate, and a pixel electrode is formed on the glass substrate, wherein the pixel electrode is an IPS driving electrode having a pair of ITO electrodes (electrode width is 10 μm, electrode interval is 10 μm, and electrode height is 50 nm), and the pair of ITO electrodes have a comb-like shape, and the comb-like parts of each other are configured in a separated and biting manner. Then, the glass substrate coated with the liquid crystal alignment agent is dried on a hot plate at 80°C for 3 minutes, and then baked in a hot air circulation oven at 250°C for 30 minutes to form a coating film with a thickness of 100 nm.

[0322] After irradiating the coating surface with ultraviolet light having a wavelength of 254 nm through a polarizing plate, the substrate was baked in a hot air circulation oven at 250° C. for 30 minutes to obtain a substrate having a liquid crystal alignment film. Similarly, a coating was formed on an opposing substrate and an alignment treatment was applied, wherein the opposing substrate was a glass substrate having no electrode formed thereon but having a columnar spacer having a height of 4 μm.

[0323] The above two substrates are a set, and a sealant is printed on one of them, and the other is bonded in a manner that it faces the liquid crystal alignment film and the orientation direction is 0°, and then the sealant is hardened to obtain an empty cell. This empty cell is injected with liquid crystal MLC-2041 (Merck) by a reduced pressure injection method, and the injection port is sealed to obtain the liquid crystal display element of Example 1. The obtained liquid crystal display element is evaluated by the following evaluation method, and the results are shown in Table 3, among which the detection method of charge relaxation speed and AC residual image will be described later.

[0324] Examples 2 to 15 and Comparative Examples 1 to 3

[0325] Examples 2 to 15 and Comparative Examples 1 to 3 use the same preparation method as the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of Example 1, the difference is that Examples 2 to 15 and Comparative Examples 1 to 3 change the type and usage of raw materials in the liquid crystal alignment agent. The formulas and evaluation results are shown in Table 3, which will not be further described here.

[0326]

[0327] Evaluation method

[0328] Charge relaxation rate: The liquid crystal display element prepared by the above-mentioned embodiment and comparative example is placed on a light source, and the VT characteristics (voltage-pass rate characteristics) at a temperature of 25°C are measured, and then the pass rate (Ta) of the liquid crystal cell under the state of applying a rectangular wave of ±3V / 120Hz is measured. After that, at a temperature of 25°C, a rectangular wave of ±3V / 120Hz is applied for 10 minutes, and then a DC of 2V is superimposed and driven for 60 minutes. The DC voltage is cut off, and the pass rate (Tb) of the liquid crystal cell when driven by AC for 60 minutes is measured, and the difference between the pass rate (Ta) and the initial pass rate (ΔT=Tb-Ta) is used to calculate the difference in pass rate caused by the residual voltage in the liquid crystal display element. Among them, the smaller the difference in pass rate (ΔT), the faster the charge relaxation rate, and the charge relaxation rate is evaluated according to the following criteria.

[0329] ※:ΔT≤0.5.

[0330] ◎:0.5<ΔT≤1.

[0331] ○: 1<ΔT≤1.5.

[0332] ×: ΔT>1.5.

[0333] AC Afterimage

[0334] After the liquid crystal display elements prepared in each embodiment and comparative example were driven for 30 hours by applying an AC voltage of 10V, the brightness change rate (%) under 1.5V driving represented by the following formula (II) was measured using a device having a polarizer and an analyzer arranged between the light source and the light intensity detector.

[0335]

[0336] In formula (II), β(0) is the light transmittance of the liquid crystal display element under 1.5V drive before the driving stress is sandwiched between the polarizer and the analyzer under orthogonal Nicols, and β(30hr) is the light transmittance of the liquid crystal display element under 1.5V drive after being sandwiched between the polarizer and the analyzer under orthogonal Nicols for 30 hours.

[0337] AC image sticking is expressed by the grayscale at 1.5V driving 30 hours before AC voltage driving and the brightness change rate at 1.5V driving 30 hours after AC voltage driving. The smaller the change rate, the lower the AC image sticking. Among them, AC image sticking is evaluated according to the following criteria.

[0338] ◎: Brightness change rate ≤ 1% under 1.5V driving.

[0339] ○: 1%<1.5V driving brightness change rate ≤2%.

[0340] △: 2%<1.5V driving brightness change rate ≤3%.

[0341] ×: Brightness change rate under 1.5V driving>3%.

[0342] From the results of Table 3, it can be seen that if the diamine component (a2) of the liquid crystal alignment agent of the present invention does not include the diamine compound (a2-1) shown in formula (A21), the liquid crystal display element containing the liquid crystal alignment film prepared therefrom will have a slower charge relaxation rate and a higher AC afterimage. Among them, if the ring Z of formula (A21) represents a phenyl group, the liquid crystal alignment film prepared therefrom can further improve the charge relaxation rate of the liquid crystal display element. Secondly, when the diamine compound (a2-1) shown in formula (A21) includes at least one of the compounds shown in formula (A21-1) and formula (A21-2), the liquid crystal alignment film prepared can also further improve the charge relaxation rate of the liquid crystal display element. When the diamine component (a2) comprises at least one of a diamine compound (a2-2) as shown in formula (A22) and a diamine compound (a2-5) as shown in formula (A25), the resulting liquid crystal alignment film can more effectively reduce the AC image sticking of the liquid crystal display element. In addition, if the tetracarboxylic acid derivative component (a1) of the liquid crystal alignment agent comprises an alicyclic tetracarboxylic dianhydride compound (a1-1) as shown in formula (A11), the resulting liquid crystal alignment film can more effectively reduce the AC image sticking of the liquid crystal display element.

[0343] It should be added that, although the present invention uses specific compounds, compositions, reaction conditions, processes, analysis methods or specific instruments as examples to illustrate the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of the present invention, anyone with common knowledge in the technical field to which the present invention belongs can know that the present invention is not limited thereto. Without departing from the spirit and scope of the present invention, the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element of the present invention may also be carried out using other compounds, compositions, reaction conditions, processes, analysis methods or instruments.

[0344] Although the present invention has been disclosed as above in the form of an implementation method, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A liquid crystal alignment agent, characterized in that: Include: The polymer (A) has a structure shown in the following formula (I): In formula (I), X1 and X1′ each independently represent a chain hydrocarbon group having 1 to 10 carbon atoms or a single bond; X2 and X2′ each independently represent —O—, —S—, —CO— or —COO—; X3 and X3′ each independently represent a chain hydrocarbon group having 1 to 10 carbon atoms or a single bond; X1, X1′, X3 and X3′ cannot all be single bonds; Ring Z represents an aromatic hydrocarbon ring, diphenyl ether or a nitrogen-containing heterocycle; B1 and B2 each independently represent a divalent organic group as shown in the following structure, and B1 and B2 do not have the same structure; “*” represents a bonding position; In the above structure, R4 represents an alkylene group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, a methyl group, a hydroxyl group or a methoxy group.

2. The liquid crystal alignment agent according to claim 1, characterized in that: X3 and X3' each independently represent a single bond.

3. The liquid crystal alignment agent according to claim 1, characterized in that: The structure represented by formula (I) is at least one selected from the group consisting of the structures represented by the following formula (I-1) and formula (I-2):

4. The liquid crystal alignment agent according to claim 1, characterized in that: The ring Z represents a phenylene group.

5. The liquid crystal alignment agent according to claim 1, characterized in that: The polymer (A) is at least one selected from the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic acid derivative component (a1) with a diamine component (a2), and an imidized polymer of the polyimide precursor, wherein the diamine component (a2) comprises a diamine compound (a2-1) represented by the following formula (A21): In formula (A21), X1, X1′, X2, X2′, X3, X3′, B1, B2 and ring Z are as defined above.

6. The liquid crystal alignment agent according to claim 5, characterized in that: The diamine compound (a2-1) represented by formula (A21) is at least one selected from the group consisting of the structures represented by the following formula (A21-1) and formula (A21-2):

7. The liquid crystal alignment agent according to claim 5, characterized in that: The diamine component (a2) comprises at least one of the group consisting of a diamine compound (a2-2) represented by the following formula (A22) and a diamine compound (a2-5) represented by the following formula (A25): In formula (A22), Ar represents a divalent aromatic group of a benzene ring, a biphenyl ring or a naphthalene ring, and the hydrogen atoms of the benzene ring or the biphenyl structure may be substituted by a monovalent substituent or may not be substituted; m and n each independently represent an integer from 1 to 3; any hydrogen atom on the benzene ring to which the two terminal amine groups are bonded may be substituted by a monovalent substituent or may not be substituted; H2N-A 1 -Y 11 -L 1 -Y 11 -A 2 -NH2 (A25) In formula (A25), A 1 and A 2 Each independently represents a substituted or unsubstituted divalent aromatic ring group; Y 11 represents -O-, -S-, .COO- or -OCO-; L 1 represents the structure represented by the following formula (L1-1); In formula (L1-1), K 1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; h is an integer from 0 to 4. When h is an integer from 2 to 4, K 1 Each independently has the above definition; j is an integer from 1 to 3, when j is 2 or 3, K 1 and h each independently have the above definitions, and “*” represents a bonding position.

8. The liquid crystal alignment agent according to claim 7, characterized in that: The diamine compound (a2-2) represented by formula (A22) is at least one selected from the group consisting of the structures represented by the following formulas (A22-1) to (A22-3):

9. The liquid crystal alignment agent according to claim 7, characterized in that: The diamine compound (a2-5) shown in formula (A25) has a structure shown in formula (A25-1): In formula (A25-1), A 1 , A 2 and Y 11 The definitions of are the same as those in formula (A25), and K 1 The definitions of , h and j are the same as those in formula (L1-1).

10. The liquid crystal alignment agent according to claim 5, characterized in that: The tetracarboxylic acid derivative component (a1) comprises an alicyclic tetracarboxylic dianhydride compound or a derivative thereof (a1-1) represented by the following formula (A11): In formula (A11), R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, R1 to R4 may be the same or different, and at least one of R1, R2, R3 and R4 is not a hydrogen atom.

11. The liquid crystal alignment agent according to any one of claims 1 to 10, characterized in that: The liquid crystal alignment agent is configured to prepare a liquid crystal alignment film used in a photo-alignment treatment method.

12. A liquid crystal alignment film, characterized in that: The liquid crystal alignment agent is formed using any one of claims 1 to 11.

13. A liquid crystal display element, characterized in that: It comprises the liquid crystal alignment film as claimed in claim 12.

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