Liquid crystal alignment agent, manufacturing method thereof, liquid crystal alignment film and liquid crystal display assembly

Abstract

The invention provides a liquid crystal alignment agent, a preparation method thereof, a liquid crystal alignment film and a liquid crystal display assembly. The liquid crystal alignment agent comprises a polymer (A) and a solvent (C). The polymer (A) is prepared by reacting a specific tetracarboxylic acid derivative component (A1) and a diamine component (A2). The liquid crystal alignment film can be formed by the liquid crystal alignment agent, and the liquid crystal display component comprising the liquid crystal alignment film has low real-time flicker degree after driving.

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent suitable for forming a liquid crystal alignment film, and a liquid crystal alignment film formed by the liquid crystal alignment agent. The present invention relates to a method for forming a liquid crystal alignment film and a liquid crystal display component having the liquid crystal alignment film. Background Art

[0002] Liquid crystal display components used in liquid crystal televisions, liquid crystal monitors, etc., are usually provided with a liquid crystal alignment film inside the component for controlling the arrangement state of the liquid crystal. Currently, the most common method in the industry is to rub the surface of a film formed on an electrode substrate and formed of polyamic acid and / or polyimide imidized therefrom in one direction with a cloth such as cotton, nylon, polyester, etc., to produce the liquid crystal alignment film by so-called rubbing treatment.

[0003] During the alignment process of the liquid crystal alignment film, the film surface is rubbed to treat the film, which is a relatively easy method to produce in industry. However, with the increasing requirements for high performance, high precision and large-scale liquid crystal display components, during the rubbing treatment, the damage to the alignment film surface, flying dust, the influence of mechanical force and electrostatic force, and the unevenness on the alignment treatment surface become more and more obvious.

[0004] As a method to replace the friction treatment, there is currently known a photo-alignment method that uses polarized ultraviolet irradiation to impart alignment energy to the liquid crystal. The so-called photo-alignment method for liquid crystal alignment treatment includes substances that use photoisomerization reactions, substances that use photocrosslink reactions, substances that use photodecomposition reactions, etc. in the reaction mechanism. Furthermore, Japanese Patent Publication No. 9-297313 proposes that the photo-alignment method uses a polyimide film whose main chain has an alicyclic structure such as cyclobutane. When using polyimide as an alignment film for photo-alignment, because the heat resistance of this alignment film is higher than that of other types of alignment films, the applicability of this alignment film is optimistic. The optical alignment method is a method of alignment treatment without friction. In industry, it not only has the advantage of being manufactured using a simple process, but also in liquid crystal display components using lateral electric field effect technology (In-Plane-Switching; IPS) driving mode and boundary electric field switching wide viewing angle technology (Fringe Field Switching; FFS) driving mode, the contrast and viewing angle characteristics of the liquid crystal display components can be improved when the liquid crystal alignment film obtained by the optical alignment method is compared with the liquid crystal alignment film obtained by the friction treatment method. Therefore, the optical alignment method is a promising and highly anticipated liquid crystal alignment treatment method.

[0005] However, when the liquid crystal alignment film obtained by the photo-alignment method is applied to a liquid crystal display component, the obtained liquid crystal display component still has the problem of high real-time flicker after driving, that is, the accumulated charge of the liquid crystal alignment film after being illuminated is slowly eliminated, resulting in excessive residual charge, and then generating the problem of afterimage. As can be seen from the above, in order to meet the requirements of the current light-aligned IPS type liquid crystal display industry, providing a liquid crystal alignment agent that can form a liquid crystal display component with low real-time flicker after driving is the goal of the technical field. Summary of the invention

[0006] One aspect of the present invention is to provide a liquid crystal alignment agent, which comprises a polymer (A) and a solvent (C), and the liquid crystal alignment agent can selectively comprise a polymer (B). The liquid crystal alignment film prepared by using the liquid crystal alignment agent has good liquid crystal alignment and can effectively reduce the real-time flicker of the prepared liquid crystal display element after driving.

[0007] Another aspect of the present invention is to provide a method for preparing a liquid crystal alignment agent, which is formed by mixing a polymer (A) and a solvent (C), and can selectively mix a polymer (B) to prepare the liquid crystal alignment agent.

[0008] Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed by using the aforementioned liquid crystal alignment agent.

[0009] Another aspect of the present invention is to provide a liquid crystal display component, which includes the aforementioned liquid crystal alignment film.

[0010] According to the above aspect of the present invention, a liquid crystal alignment agent is provided. The liquid crystal alignment agent comprises a polymer (A) and a solvent (C), and the liquid crystal alignment agent may selectively comprise a polymer (B), which is described below.

[0011] Polymer (A)

[0012] The liquid crystal alignment agent of the present invention comprises a polymer (A), and the polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor having a structure represented by the following formula (a-1) and formula (a-2) at the end of the polymer main chain, and an imide compound (i.e., polyimide) of the polyimide precursor. Specific examples of such a polymer include a polyimide precursor having an imide precursor structure such as polyamic acid and polyamic acid ester, and the imide compound of the polyimide precursor is polyimide.

[0013]

[0014] In formula (a-1) and formula (a-2), M 1 Represents a single bond or a carbonyl group; M 2represents a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group as shown in the following formula (a-3).

[0015]

[0016] In formula (a-3), M 3 It is a group selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0017] By heat treatment, the terminal group containing an amic acid structure as shown in formula (a-1) can be converted into a terminal group containing a phthalimide structure as shown in formula (a-2).

[0018] When the end of the polymer main chain does not have the structure shown in formula (a-1) or formula (a-2), the resulting liquid crystal display component has a problem of excessively high real-time flicker after driving.

[0019] In formula (a-1) and formula (a-2), M 2 Preferably, M represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, and more preferably represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms. 3 It is preferably selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms.

[0020] When M of formula (a-1) and formula (a-2) 2 represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, and M of formula (a-3) 3 When M is selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, the real-time flicker of the liquid crystal display component after driving can be further reduced. 2 represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms, and M in formula (a-3) 3 When the group is selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, the real-time flicker of the liquid crystal display component after driving can be further reduced.

[0021] The aforementioned saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms may include, but is not limited to, methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, isoheptyl, octyl, isooctyl, nonyl, decyl or other suitable saturated aliphatic hydrocarbon groups.

[0022] The aforementioned alkyl group with a carbon number of 1 to 10 may include, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, octyl, nonyl, decyl or other appropriate alkyl groups. The aforementioned alkoxy group with a carbon number of 1 to 6 may include, but is not limited to, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy, neopentyloxy, hexyloxy or other appropriate alkoxy groups.

[0023] In formula (a-1) and formula (a-2), based on the viewpoint of easy availability, M 1 Preferably, it is a single bond.

[0024] In formula (a-1) and formula (a-2), based on the viewpoint of the ease of synthesis, M 2 Preferably, it may contain a methyl group or a phenyl group.

[0025] The polymer (A) may be an imidized polyimide precursor obtained by polymerizing a tetracarboxylic acid derivative component (A1) and a diamine component (A2), and during and / or after the polymerization reaction, a compound represented by the following formula (a-4) is added to the reaction solution so that the formed polymer (A) has terminal groups having structures represented by formulas (a-1) and (a-2).

[0026]

[0027] In formula (a-4), M 1 represents a single bond or a carbonyl group; M 2 represents a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group as shown in the following formula (a-3).

[0028]

[0029] In formula (a-3), M 3 It is a group selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0030] In some embodiments, M of formula (a-4) 2 represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms or an aromatic hydrocarbon group as shown in formula (a-3), and in formula (a-3), M 3 It is a group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0031] In other embodiments, M of formula (a-4) 2 represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms or an aromatic hydrocarbon group as shown in formula (a-3), and in formula (a-3), M 3It is a group selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.

[0032] In some specific examples, the compound represented by formula (a-4) may include but is not limited to the compounds represented by the following formulas (a-4-1) to (a-4-19).

[0033]

[0034]

[0035]

[0036]

[0037] Based on the usage amount of the diamine component (A2) being 100 mol%, the usage amount of the compound represented by formula (a-4) is 2 mol% to 60 mol%, preferably 3 mol% to 50 mol%, and more preferably 4 mol% to 40 mol%.

[0038] When the usage of the compound represented by formula (a-4) is within the aforementioned range, the prepared liquid crystal alignment film can effectively reduce the real-time flickering degree of the liquid crystal display component after being driven.

[0039] In some embodiments, the polymer (A) may include a structure as shown in the following formula (a-5).

[0040] *-R 1 -R 4 -R 2 -R 6 -R 5 -R 7 -R 3 -* (a-5)

[0041] In formula (a-5), R 1 , R 2 With R 3 Each independently represents a divalent organic group of a benzene ring or a pyridine ring; R 4 represents an oxygen atom or a sulfur atom; R 5 represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 30 carbon atoms; R 6 and R 7 Each independently represents a single bond, an oxygen atom, a sulfur atom or -NR 8 -, where R 6 and R 7 At least one of represents an oxygen atom, a sulfur atom or -NR 8 -, and R 8 represents a hydrogen atom or a methyl group; when R 1 , R2 With R 3 When any one of is a pyridine ring, R 6 and R 7 It does not represent a single bond; "*" represents the bond position.

[0042] When the polymer (A) contains a structure as shown in formula (a-5), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0043] In some embodiments, the polymer (A) of the present invention may selectively include a structure represented by at least one of the following formulas (a-6), (a-7), and (a-8).

[0044]

[0045] *-D 1 -D 3 -D 5 -D 4 -D 2 -* (a-8)

[0046] In formula (a-6), Z 7 represents an oxygen atom or a sulfur atom; Z 3 With Z 4 Each independently represents an alkylene group having 1 to 3 carbon atoms; Z 1 With Z 2 Each independently represents a single bond, -O-, -S-, -OCO- or -COO-; and Z 5 With Z 6 Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a protective group substituted by a hydrogen atom by heat, wherein Z 5 With Z 6 At least one of represents a protecting group which is substituted with a hydrogen atom by heat.

[0047] In the above formula (a-7), A 1 , A 2 , A 3 With A 4 Each independently represents a monovalent hydrocarbon group, and A 1 , A 2 , A 3 With A 4 are the same or different; A5 each independently represents a divalent hydrocarbon group, and A 5 are the same or different; a represents an integer from 1 to 10.

[0048] In the above formula (a-8), D 1 With D 2represents a divalent aromatic ring group, the ring part of the aromatic ring group may have a substituent, and D 1 With D 2 are the same; D 3 Representative-ND 31 -, and D 31 represents a protecting group replaced by a hydrogen atom by heat; D 4 represents a single bond, oxygen atom or sulfur atom; D 5 represents a divalent group having at least one of a chain hydrocarbon structure having 1 to 15 carbon atoms and an alicyclic hydrocarbon structure having 3 to 15 carbon atoms; when D 4 When it is a sulfur atom, D 5 The carbon number is greater than and equal to 2.

[0049] When polymer (A) contains a structure as shown in at least one of formula (a-6), formula (a-7) and formula (a-8), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0050] Tetracarboxylic acid derivative component (A1)

[0051] The polyimide precursor contained in the liquid crystal alignment agent of the present invention is prepared by reacting the tetracarboxylic acid derivative component (A1) with the diamine component (A2), and the polyimide contained in the liquid crystal alignment agent of the present invention is prepared by imidization of the aforementioned polyimide precursor. The specific examples of the materials used and the preparation method will be described in detail below.

[0052] The tetracarboxylic acid derivative component (A1) may include at least one of the group consisting of alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) and other tetracarboxylic dianhydrides (a1-2).

[0053] Alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11)

[0054] The tetracarboxylic acid derivative component (A1) used for the reaction to obtain the polymer (A) may include an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof as shown in the following formula (A11). The alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof shown in formula (A11) may be composed of a single tetracarboxylic dianhydride or a derivative thereof, or may be composed of a plurality of tetracarboxylic dianhydrides or derivatives thereof. In the present invention, the alicyclic tetracarboxylic dianhydride (a1-1) may be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. However, none of the four carboxyl groups are bonded to an aromatic ring. Alternatively, it is not necessary to be composed only of an alicyclic structure, and a portion thereof may also have a chain hydrocarbon structure or an aromatic ring structure. The aromatic tetracarboxylic dianhydride may be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. However, it is not necessary to consist of only an aromatic ring structure, and a part of it may have a chain hydrocarbon structure or an alicyclic structure. Non-cyclic aliphatic tetracarboxylic dianhydride may be, for example, an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it is not necessary to consist of only a chain hydrocarbon structure, and a part of it may have an alicyclic structure or an aromatic ring structure.

[0055]

[0056] In formula (A11), X 1 At least one of the structures shown in the following formula (I-1) to (I-7) may be selected, and "*" represents a bonding position.

[0057]

[0058] In formula (I-1), X 11 , X 12 , X 13 With X 14 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. 15 With X 16 Each independently represents a hydrogen atom or a methyl group.

[0059] In some embodiments, X 1 The structures shown in the following formulae (I-1-1) to (I-1-6) may be represented.

[0060]

[0061]

[0062] The aforementioned alicyclic tetracarboxylic dianhydride (a1-1) may be used alone or in combination of plural types.

[0063] Other tetracarboxylic dianhydride derivatives (a1-2)

[0064] The other tetracarboxylic dianhydride derivative (a1-2) of the present invention may include a tetracarboxylic dianhydride compound represented by the following formula (A12) and a derivative thereof.

[0065]

[0066] In formula (A12), X 1 ' may represent the structures shown in the following formulas (A12-1) to (A12-32), wherein "*" represents the bonding position. In formulas (A12-5) and (A12-6), X 11 ′ and X 12 'respectively independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide, and 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 alignment, 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.

[0067]

[0068]

[0069]

[0070]

[0071] In some specific examples, the aforementioned formula (A12-5) and formula (A12-6) may include but are not limited to the structures shown below.

[0072]

[0073]

[0074] The above-mentioned other tetracarboxylic dianhydride derivatives (a1-2) may be used alone or in combination of plural kinds.

[0075] Diamine component (A2)

[0076] The diamine component (A2) of the present invention may include a diamine compound (a2-1) represented by formula (A21), a diamine compound (a2-2) and another diamine compound (a2-3).

[0077] The diamine component (A2) used for the reaction to obtain the polymer (A) may include a diamine compound (a2-1) represented by the following formula (A21).

[0078] H 2 NR 1 -R 4 -R 2 -R 6 -R 5 -R 7 -R 3 -NH 2 (A21)

[0079] In formula (A21), R 1 , R 2 and R 3 Each independently represents a divalent organic group of a benzene ring or a pyridine ring; R 4 represents an oxygen atom or a sulfur atom; R 5 represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 30 carbon atoms; R 6 and R 7 Each independently represents a single bond, an oxygen atom, a sulfur atom or -NR 8 -, where R 6 and R 7 At least one of represents an oxygen atom, a sulfur atom or -NR 8 -, and R 8 represents a hydrogen atom or a methyl group; when R 1 , R 2 and R 3 When any one of is a pyridine ring, R 6 and R 7 Does not represent a single bond.

[0080] The aforementioned R 5 Preferably, it represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 11 carbon atoms, and most preferably a straight chain alkylene group having 1 to 11 carbon atoms. 5 When it represents the aforementioned substituent, the obtained liquid crystal display component containing the liquid crystal alignment film formed by using the liquid crystal alignment agent can further reduce the real-time flicker after driving.

[0081] The aforementioned "chain hydrocarbon group" refers to a straight-chain or branched hydrocarbon group that does not contain a cyclic structure in the main chain and is only composed of a chain structure, which may be saturated or unsaturated. The aforementioned "alicyclic hydrocarbon group" refers to a hydrocarbon group containing an alicyclic structure and does not contain an aromatic ring structure. However, it does not have to be composed only of hydrocarbon groups with an alicyclic structure, and some of them may have a chain structure. In the specific example of a divalent chain hydrocarbon group with a carbon number of 1 to 30, these hydrocarbon groups may include saturated and unsaturated chain hydrocarbon groups. Saturated chain hydrocarbon groups may be saturated straight-chain or branched hydrocarbon groups. Saturated straight-chain hydrocarbon groups may be, for example, methylene, ethyl, propanediyl, butanediyl, pentanediyl, hexanediyl, heptanediyl, octanediyl, nonanediyl, decanediyl, dodecanediyl, tetradecanediyl, pentadecanediyl, hexadecanediyl, octadecanediyl, or other appropriate saturated straight-chain hydrocarbon groups. The saturated branched hydrocarbon group may be, for example, sec-butanediyl, t-butanediyl, isopentanediyl, t-pentanediyl, isooctanediyl, 2-ethylhexanediyl, t-octanediyl, isononanediyl, isodecanediyl, or other suitable saturated branched hydrocarbon groups.

[0082] 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. For example: ethylenediyl, heptenediyl, 2-butenediyl, 3-methyl-4-ethyl-1-hexenediyl, propynediyl, 2-hexynediyl, 3-methyl-1-pentynediyl, 3-ethyl-1-heptynediyl, 3,5-dimethyl-4-hexene-1-heptynediyl, or other suitable unsaturated chain hydrocarbon groups. Specific examples of alicyclic hydrocarbon groups having 3 to 30 carbon atoms may include cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, groups in which the hydrogen atoms on the aforementioned ring groups are substituted, or other suitable alicyclic hydrocarbon groups.

[0083] Specific examples of the diamine compound (a2-1) represented by the formula (A21) are described below in detail.

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] In the above formulae (A21-1), (A21-3), (A21-5), (A21-6), (A21-8), (A21-14) and (A21-24) to (A21-34), Ra represents a hydrogen atom or a methyl group, but is not limited thereto and may also represent other groups.

[0092] The aforementioned diamine compound (a2-1) may be used alone or in combination of two or more.

[0093] In the synthesis of a fully obtained polymer (A) (such as polyamic acid (PAA)), based on the usage of the diamine component (A2) as 100 mol%, the usage of the diamine compound (a2-1) shown in the above formula (A21) is 5 mol% to 60 mol%, preferably 7 mol% to 50 mol%, and more preferably 10 mol% to 40 mol%.

[0094] When the amount of the diamine compound (a2-1) used is within the aforementioned range, the prepared liquid crystal alignment film can effectively reduce the real-time flickering of the liquid crystal display component after driving. The main synthesis method of the diamine compound (a2-1) is described in detail below. The following synthesis method is only an example, and the present invention is not limited thereto.

[0095] As shown in the following reaction formula (I), the diamine compound (a2-1) is obtained by reducing a dinitro compound to convert the nitro group into an amino group. This reaction formula records the diamine compound (a2-1) shown in the aforementioned formula (A21-7) in the embodiment, which is only used as an example.

[0096]

[0097] The reduction method of the dinitro compound is not particularly limited. Examples include palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, platinum sulfide carbon, etc., as catalysts, in solvents such as ethyl acetate, toluene, tetrahydrofuran, dioxane and alcohols, and reduction by hydrogen, hydrazine and hydrogen chloride. It is also possible to use an autoclave under pressure as needed. 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, or tin chloride as a catalyst for the reduction condition.

[0098] In the synthesis of dinitro compounds, as shown in the following reaction formula (II), a commercially available diphenyl ether derivative, phenoxypyridine derivative or bipyridine ether derivative can be reacted with a leaving group (R 1 ') substituted nitrobenzene or nitropyridine to obtain a dinitro compound. A preferred leaving group (R 1'), and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a toluenesulfonate (-OTs), and a mesylate (-OMs).

[0099]

[0100] The above reaction can be carried out in the presence of a base. The base used is not particularly limited as long as it can be synthesized, 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 the like; and organic bases such as pyridine, dimethylaminopyridine, trimethylamine, triethylamine, tributylamine, and the like. Depending on the situation, when a palladium catalyst or a copper catalyst such as dibenzylideneacetone palladium or diphenylphosphinoferrocene palladium is used in combination, the yield can be increased. From the viewpoint of easy synthesis, the method using potassium carbonate is preferred, but synthesis is also possible other than this method, so the synthesis method is not particularly limited.

[0101] When the diamine component (A2) contains at least the diamine compound (a2-1) represented by the above formula (A21), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0102] Diamine compound (a2-2)

[0103] The diamine component (A2) of the present invention may further include a diamine compound (a2-2), and the diamine compound (a2-2) includes at least one of a group consisting of a diamine compound (a2-2-1) shown in the following formula (A22-1), a diamine compound (a2-2-2) shown in the following formula (A22-2) and a diamine compound (a2-2-3) shown in the following formula (A22-3).

[0104] The diamine compound (a2-2-1) represented by the formula (A22-1)

[0105] The diamine compound (a2-2-1) of the present invention has a structure represented by the following formula (A22-1).

[0106]

[0107] In formula (A22-1), Z 7 represents an oxygen atom or a sulfur atom; Z 3 With Z 4 Each independently represents an alkylene group having 1 to 3 carbon atoms; Z 1 With Z 2 Each independently represents a single bond, -O-, -S-, -OCO- or -COO-; and Z 5 With Z 6 Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a protective group substituted by a hydrogen atom by heat, wherein Z5 With Z 6 At least one of represents a protecting group which is substituted with a hydrogen atom by heat.

[0108] When the aforementioned Z 5 With Z 6 When at least one of represents a group as shown in the following formula (i-1), the prepared liquid crystal alignment film can further reduce the real-time flicker of the prepared liquid crystal display element after driving.

[0109]

[0110] In formula (i-1), Z 8 A divalent organic group representing a single bond or a hydrocarbon group having 1 to 4 carbon atoms.

[0111] The aforementioned alkylene group having 1 to 3 carbon atoms may be a straight chain or branched chain alkylene group, and may be, for example, a methylene group, an ethylene group, a propylene group, a 1-methylethylene group, or a 2-methylethylene group. Among them, from the viewpoint of low real-time flicker after driving, it is preferred to select a structure having more free rotation parts and less steric hindrance. For example, the alkylene group having 1 to 3 carbon atoms may preferably be a methylene group, an ethylene group, or a propylene group.

[0112] In formula (A22-1), Z 1 With Z 2 In the case of low-drive real-time flicker, Z 1 With Z 2 It is better to use a structure with flexibility and small steric hindrance, so Z 1 With Z 2 Preferred is a single bond, -O- or -S-.

[0113] In order to form a film with high density and a liquid crystal alignment film with better alignment, the structure between the (thio)urea group and the benzene ring is preferably symmetrical based on the (thio)urea group as the center. 1 -Z 3 -and-Z 4 -Z 2 - preferably have the same structure. In addition, the diamine compound (a2-2-1) represented by formula (A22-1) may preferably be a compound represented by the following formulas (i-2) to (i-4). In the following formula (i-2), Z 31 and Z 41 represents an alkylene group having 1 to 3 carbon atoms, and each of them has the same carbon number; Z 5 With Z 6 The definition of is as described above. In the following formula (i-3), Z 32 and Z 42 represents an alkylene group having 1 to 3 carbon atoms, and each of them has a different carbon number; Z 5 With Z6 The definition of is as described above. In the following formula (i-4), Z 33 and Z 43 Each independently represents an alkylene group having 1 to 3 carbon atoms; Z 5 With Z 6 The definition of is as mentioned above.

[0114]

[0115] In formula (i-2) to formula (i-4), Z 5 With Z 6 At least one of represents a protecting group substituted by a hydrogen atom by heat. The protecting group substituted by a hydrogen atom by heat may be, for example, a carbamate protecting group, an amide protecting group, an imide protecting group or a sulfonamide protecting group, and specific examples thereof may include, for example, tert-butyloxycarbonyl, benzyloxycarbonyl, 1,1-dimethyl-2-haloethoxycarbonyl, 1,1-dimethyl-2-cyanoethoxycarbonyl, 9-fluorenylmethoxycarbonyl, allyloxycarbonyl, or 2-(trimethylsilyl)ethoxycarbonyl.

[0116] Specific examples of the diamine compound (a2-2-1) represented by the above formula (A22-1) include diamine compounds represented by the following formulae (A22-1-1) to (A22-1-40).

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124] In formula (A22-1-1) to formula (A22-1-40), Boc represents the structure represented by the aforementioned formula (i-1).

[0125] The aforementioned diamine compound (a2-2-1) may be used alone or in combination of two or more.

[0126] A diamine compound (a2-2-2) represented by formula (A22-2)

[0127] The diamine compound (a2-2-2) of the present invention has a structure represented by the following formula (A22-2).

[0128]

[0129] In formula (A22-2), A 1 , A 2 , A 3 and A 4 For the same or different, A 1 , A 2 , A 3 and A 4 A represents a monovalent hydrocarbon group 5 Can be the same or different, A 5 each independently represents a divalent hydrocarbon group; and a represents an integer of 1 to 10.

[0130] For example, specific examples of the diamine compound (a2-2-2) shown in formula (A22-2) may include but are not limited to 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(4-aminobutyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetraphenyldisiloxane, 1,3-bis(4-amino-3-methylphenyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(3-aminopropyl)-1,3-diphenyl-1,3-dimethyldisiloxane, 1,5-bis(3-aminopropyl)-1,3,3,5-tetraphenyl-1,5-dimethyltrisiloxane, other appropriate diamine compounds, or any mixture of the above diamine compounds. Preferably, the diamine compound (a2-2-2) may be 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetraphenyldisiloxane, or 1,5-bis(3-aminopropyl)-1,3,3,5-tetraphenyl-1,5-dimethyltrisiloxane.

[0131] The aforementioned diamine compound (a2-2-2) may be used alone or in combination of two or more.

[0132] The diamine compound (a2-2-3) represented by the formula (A22-3)

[0133] The diamine compound (a2-2-3) of the present invention has a structure represented by the following formula (A22-3).

[0134] H 2 ND 1 -D 3 -D 5 -D 4 -D 2 -NH 2 (A22-3)

[0135] In formula (A22-3), D 1 With D 2 represents a divalent aromatic ring group, the ring part of the aromatic ring group may have a substituent, and D 1 With D 2 are the same; D 3 Representative-ND 31 -, and D 31 represents a protecting group replaced by a hydrogen atom by heat; D 4 represents a single bond, an oxygen atom or a sulfur atom; D5 represents a divalent group having at least one of a chain hydrocarbon structure having 1 to 15 carbon atoms and an alicyclic hydrocarbon structure having 3 to 15 carbon atoms; when D 4 When D represents sulfur atom, 5 The carbon number is greater than or equal to 2.

[0136] In formula (A22-3), D 1 and D 2 is a group formed by removing two hydrogen atoms from the ring part of an aromatic ring, and may also have a substituent on the ring part. For example, as an aromatic ring, D 1 and D 2 The aromatic ring may include, but is not limited to, an aromatic hydrocarbon ring such as a benzene ring, a naphthalene ring, an anthracene ring, or a biphenyl ring; or a nitrogen-containing heterocyclic ring such as a pyridine ring, a pyrimidine ring, a pyrazine ring, or a pyridazine ring. The substituent of the aromatic ring may be, for example, an alkyl group having 1 to 6 carbon atoms. 1 and D 2 Since the two monomers are the same, they can be easily synthesized to produce the monomer of polymer (A) and reduce the real-time flicker of the liquid crystal display component after driving. 1 and D 2 Preferably, the group is formed by removing two hydrogen atoms from the ring portion of a benzene ring, biphenyl ring, pyridine ring or pyrimidine ring having a substituent, so as to obtain a liquid crystal display component with lower real-time flicker after driving.

[0137] In formula (A22-3), when D 3 Representative-ND 31 -, D 31 represents a protecting group which is replaced by a hydrogen atom by heat, and D 4 When it represents a single bond, oxygen atom or sulfur atom, it can effectively reduce the real-time flicker of the liquid crystal display component after driving. 31 The representative protecting group is preferably a carbamate protecting group, an amide protecting group, an imide protecting group or a sulfonamide protecting group. 31The representative protecting group may be a functional group as shown in the following formula (ii-1), and the aforementioned protecting group is a high heat leaving group and reduces the residual group of the deprotected part in the liquid crystal alignment film. 31 When it represents a protecting group substituted with a hydrogen atom by heat, the real-time flickering degree after driving caused by the photodecomposition product can be further reduced.

[0138]

[0139] In formula (ii-1), D 3 1' represents a single bond or a divalent organic group of a hydrocarbon group having 1 to 4 carbon atoms.

[0140] In formula (A22-3), D 5 A divalent group representing at least one of a chain hydrocarbon structure having 1 to 15 carbon atoms and an alicyclic hydrocarbon structure having 3 to 15 carbon atoms. Here, the so-called "chain hydrocarbon structure" refers to a straight-chain hydrocarbon structure and a branched hydrocarbon structure that do not contain a cyclic structure but only contain a chain structure. The chain hydrocarbon structure may be saturated or unsaturated. The so-called "alicyclic hydrocarbon structure" refers to a hydrocarbon structure that only contains an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. The alicyclic hydrocarbon structure is not limited to a structure that only contains alicyclic hydrocarbons, and it may also contain a portion of alicyclic hydrocarbons with a chain structure. In some embodiments, when D 4 When D represents sulfur atom, 5 The carbon number of D is greater than or equal to 2. 5 When it represents the aforementioned divalent organic group, the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0141] Preferably, the diamine compound (a2-2-3) as shown in the above formula (A22-3) may include but is not limited to the diamine compound as shown in the following formula (ii-2).

[0142]

[0143] In formula (ii-2), D 1 and D 2 represents a divalent benzene ring, a divalent pyridine ring or a divalent pyrimidine ring having two substituents, and D 1 and D 2 are the same; D 3 Representative-ND 31 -, D 31 represents a protecting group replaced by a hydrogen atom by heat, D 4 represents a single bond, an oxygen atom or a sulfur atom, and d represents an integer from 1 to 5. 4 When D represents a sulfur atom, d represents an integer from 2 to 5. 1 and D2 represents the aforementioned divalent group, D 4 When D represents a sulfur atom and d represents an integer from 2 to 5, the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving. 3 Representative-ND 31 -, and D 4 When represents a single bond, an oxygen atom or a sulfur atom, the diamine compound represented by formula (ii-2) can reduce the crystallinity of the photodegradation product of the polymer (A), thereby reducing the real-time flickering degree of the liquid crystal display component after driving. 31 represents a protecting group that is replaced by a hydrogen atom by heat, and the protecting group is preferably a group that is decomposed by endothermic cleavage, and specific examples thereof include carbamate protecting groups, amide protecting groups, imide protecting groups, and sulfonamide protecting groups, and the protecting group D 31 represents the functional group represented by the above formula (ii-1).

[0144] Based on reducing the real-time flicker after driving the liquid crystal display component, relative to the nitrogen atom in formula (ii-2), D 3 and D 4 Bonded to D 1 and D 2 The diamine compound represented by formula (ii-2) is preferably a diamine compound represented by formula (ii-3).

[0145]

[0146] In formula (ii-3), D 61 and D 62 Each independently represents -CH= or a nitrogen atom. 3 , D 4 The definitions of and d are as described above and will not be repeated here.

[0147] For example, the diamine compound (a2-2-3) may include but is not limited to the diamine compounds shown in the following formulas (A22-3-1) to (A22-3-10). Specific examples of the diamine compound (a2-2-3) can be synthesized by appropriately combining general methods of organic chemistry. In the following formulas (A22-3-1) to (A22-3-10), Rb represents t-butyloxy carbonyl.

[0148]

[0149]

[0150] The aforementioned diamine compounds (a2-2-3) may be used alone or in combination of two or more.

[0151] Based on the usage amount of the diamine component (A2) as 100 mol%, the total usage amount of the diamine compound (a2-2-1) shown in formula (A22-1), the diamine compound (a2-2-2) shown in formula (A22-2) and the diamine compound (a2-2-3) shown in formula (A22-3) is 2 mol% to 95 mol%, preferably 2.5 mol% to 93 mol%, and more preferably 3 mol% to 90 mol%.

[0152] When the diamine component (A2) includes at least one of the group consisting of a diamine compound (a2-2-1) shown in formula (A22-1), a diamine compound (a2-2-2) shown in formula (A22-2) and a diamine compound (a2-2-3) shown in formula (A22-3), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0153] Other diamine compounds (a2-3)

[0154] The diamine component (A2) used to prepare the polyimide precursor may include a diamine compound represented by the following formula (A23).

[0155] In formula (A23), X 22 and X 23 Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms. 21 The structure of is not particularly limited. Preferably, X 21 For example, the structures may be those represented by the following formulae (A23-1) to (A23-170).

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167]

[0168]

[0169]

[0170]

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180]

[0181]

[0182]

[0183] In the above structure, Me represents a methyl group, and X' represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[0184] X 21Preferably, it can be formula (A23-7), formula (A23-8), formula (A23-16), formula (A23-17), formula (A23-18), formula (A23-20), formula (A23-21), formula (A23-22), formula (A23-28), formula (A23-35), formula (A23-38), formula (A23-43), formula (A23-48), formula (A23-55), Formula (A23-57), Formula (A23-62), Formula (A23-63), Formula (A23-66), Formula (A23-67), Formula (A23-70), Formula (A23-71), Formula (A23-72), Formula (A23-73), Formula (A23-146), Formula (A23-149), Formula (A23-150), Formula (A23-156), Formula (A23-157 ), formula (A23-158), formula (A23-159), formula (A23-161) or formula (A23-163), and more preferably formula (A23-7), formula (A23-8), formula (A23-16), formula (A23-17), formula (A23-18), formula (A23-21), formula (A23-22), formula (A23-28), formula (A23-38), formula (A23 -55), formula (A23-57), formula (A23-63), formula (A23-66), formula (A23-71), formula (A23-146), formula (A23-149), formula (A23-150), formula (A23-156), formula (A23-157), formula (A23-158), formula (A23-159), formula (A23-161) or formula (A23-163).

[0185] The above-mentioned other diamine compounds (a2-3) may be used alone or in combination of plural types.

[0186] Based on 100 mol% of the tetracarboxylic acid derivative component (A1), the diamine component (A2) is used in an amount of 10 mol% to 250 mol%, preferably 20 mol% to 200 mol%, and more preferably 30 mol% to 150 mol%.

[0187] Polymer (B)

[0188] 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 reacting 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 reacting a tetracarboxylic acid derivative component (B1) and a diamine component (B2), 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 of multiple types.

[0189] Tetracarboxylic acid derivative component (B1)

[0190] 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 a derivative thereof 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.

[0191] Diamine compound (b2-1)

[0192] The diamine component (B2) of the present invention may optionally contain a diamine compound (b2-1).

[0193] As the diamine compound (b2-1), other diamine compounds (a2-3) exemplified for the above-mentioned polymer (A) may be mentioned.

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

[0195] The amount of the diamine compound (b2-1) used is not particularly limited.

[0196] Based on 100 mol% of the tetracarboxylic acid derivative component (B1), the diamine component (B2) is used in an amount of 10 mol% to 250 mol%, preferably 20 mol% to 200 mol%, and more preferably 30 mol% to 150 mol%.

[0197] When synthesizing the polymer (B) of the present invention, the tetracarboxylic acid derivative component (B1) and the diamine component (B2) as described above can be used, and an appropriate end-capping agent can be used to synthesize an end-sealed polymer. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by using the coating, and improving the sealing properties of the sealant and the liquid crystal alignment film. The end of the polymer (B) of the present invention may, for example, contain an amine group, a carboxyl group, an anhydride group or a derivative thereof. The amine group, the carboxyl group, the anhydride group or a derivative thereof can be obtained by a general condensation reaction, or by using the end-capping agent described later to seal the end. Similarly, the aforementioned derivatives can be obtained, for example, using the following end-capping agent.

[0198] 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; dicarbonyl dicarbonate, diallyl dicarbonate or the like; 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.

[0199] The blocking agents may be used alone or in combination of two or more.

[0200] From the viewpoint of improving the orientation, the usage ratio of polymer (A) to polymer (B) (i.e., the mass ratio of [polymer (A)] / [polymer (B)]) can be 10 / 90 to 90 / 10, preferably 20 / 80 to 90 / 10, and more preferably 20 / 80 to 80 / 20.

[0201] Method for making polymer

[0202] The production of polymer (A) or polymer (B) can be carried out by reacting the aforementioned diamine component and tetracarboxylic acid derivative component in solvent (C) (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 having an amic acid structure (i.e., polyamic acid) is obtained.

[0203] Solvent (C)

[0204] The solvent (C) is not particularly limited, and it only needs to be able to dissolve the formed polymer. For example, specific examples of solvent (C) may include but are 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 (C) may include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent as shown in the following formula (C1) to formula (C3). In formula (C1), Q 1 represents an alkyl group having 1 to 3 carbon atoms. In formula (C2), Q 2 represents an alkyl group having 1 to 3 carbon atoms. In formula (C3), Q 3 The substituent represents an alkyl group having 1 to 4 carbon atoms.

[0205]

[0206]

[0207] The aforementioned solvent (C) may be used alone or in combination of two or more. Furthermore, even if the solvent is insoluble in the polymer, it may be mixed with the aforementioned solvent to the extent that the generated polymer does not precipitate.

[0208] 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.

[0209] When the diamine component and the tetracarboxylic acid derivative component react in the solvent (C), 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 the reaction is carried out, 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.

[0210] 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.

[0211] 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 does not necessarily have to be 100%, and the imidization rate can be arbitrarily adjusted according to the use and / or purpose. The method for obtaining the imide compound can 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 to the outside of the system.

[0212] 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.

[0213] Solution viscosity and molecular weight of polymers

[0214] When the solution is prepared into a concentration of 10 wt% to 15 wt%, 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, 10 mPa·s to 1000 mPa·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 10 wt% to 15 wt%.

[0215] The weight average molecular weight (M) of the polymer (A) or (B) of the present invention measured by gel permeation chromatography (GPC) in terms of polystyrene is w ) is preferably 1,000 to 500,000, and more preferably 2,000 to 500,000. w The number average molecular weight (M) of the polystyrene was measured by GPC.n ) ratio represents the molecular weight distribution (M w / M n ) is preferably less than 15, and more preferably less than 10. When the molecular weight of the polymer is within the aforementioned molecular weight range, it can ensure good orientation and stability of the liquid crystal display device.

[0216] Other ingredients (D)

[0217] The liquid crystal alignment agent of the present invention comprises a polymer (A), a polymer (B) and a solvent (C) added as needed. In addition to polymer (A) and polymer (B), the liquid crystal alignment agent of the present invention may selectively comprise 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(methyl)acrylates, etc. Based on the viewpoint of forming a uniform film, the liquid crystal alignment agent takes the form of a coating liquid to prepare a liquid crystal alignment film. The liquid crystal alignment agent of the present invention is preferably a coating liquid containing the above-mentioned polymer components and an organic solvent. Among them, based on the set coating thickness to be formed, the polymer concentration in the liquid crystal alignment agent can be appropriately changed. Based on the viewpoint of forming a uniform and defect-free coating film, the polymer concentration in the liquid crystal alignment agent is preferably above 1wt%. Based on the viewpoint of the storage stability of the solution, the polymer concentration in the liquid crystal alignment agent is preferably below 10wt%. The ideal polymer concentration can be 2wt% to 8wt%. The content of polymer (A) and polymer (B) in the liquid crystal alignment agent can be appropriately changed by the coating method of the liquid crystal alignment agent and / or the film thickness of the desired liquid crystal alignment film, and is preferably 2wt% to 10wt%, and more preferably 3wt% to 7wt%.

[0218] There is no particular limitation on the organic solvent contained in the liquid crystal alignment agent, and it only needs to be able to uniformly dissolve the aforementioned polymer. Specific examples thereof 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 solvent is also called a good solvent. 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 %.

[0219] 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 properties 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 based on the coating device, coating conditions and / or coating environment of the liquid crystal alignment agent.

[0220] 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.

[0221] 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.

[0222] The solvent combination of the good solvent and the poor solvent may preferably be, 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 ethylene glycol monobutyl ether; 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 Glycol 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.

[0223] 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 substance for adjusting the dielectric constant or resistance of the liquid crystal alignment film, etc.

[0224] 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 triethylene triamine, N-trimethoxysilylpropyl triethylene triamine, vinyl trimethoxysilane, Silane coupling agents include 3-(3-trimethoxysilyl)propyl)isocyanurate, 3-isocyanatepropyltriethoxysilane and the like. When using a bonding aid, based on the viewpoint of exhibiting good resistance to AC image sticking, the amount of the bonding aid used is preferably 0.1 to 30 parts by weight, and more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the total amount of the polymer used in the liquid crystal alignment agent.

[0225] For the aforementioned cross-linking compound, based on the viewpoint of exhibiting good resistance to AC image sticking and effectively improving film strength, it may 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 (D1) and a group represented by the following formula (D2), or a compound selected from the compounds represented by the following formula (D3).

[0226]

[0227] In formula (D1), G 1 and G2 Each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH 2 -OH. In formula (D2), 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 a carbon number of 1 to 5. g1 represents an integer of 1 to 6, and g2 represents an integer of 0 to 4. In formula (D3), G 5 The (g1+g2)-valent organic group with an aromatic ring represented by the compound may be a (g1+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, 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. 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 (D3), 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.

[0228] 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 (D4) to (D6).

[0229]

[0230]

[0231] Specific examples of the compound having an propylene oxide group include compounds represented by the following formula (D7) to formula (D16).

[0232]

[0233]

[0234]

[0235] In formula (D15), R represents The “*” represents the bonding position.

[0236] Specific examples of the compound having a group represented by the formula (D1) include compounds represented by the following formulas (D1-1) to (D1-12).

[0237]

[0238]

[0239]

[0240] Specific examples of the compound having a group represented by formula (D2) include compounds represented by the following formulas (D2-1) to (D2-4).

[0241]

[0242] Specific examples of the compound having a group represented by formula (D3) include compounds represented by the following formulas (D3-1) to (D3-10).

[0243]

[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 crosslinking compound used is preferably 0.5 parts by weight to 20 parts by weight. In particular, based on the viewpoint of the crosslinking reaction and the good resistance to AC image sticking, the amount of the crosslinking compound used is more preferably 1 part by weight to 15 parts by weight.

[0247] 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 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-methylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0248] Liquid crystal alignment film and method for manufacturing liquid crystal display component

[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 a vertical alignment type (VA type) liquid crystal alignment film, and it is a liquid crystal alignment film suitable for a horizontal alignment type liquid crystal display component such as an IPS mode or a FFS mode. The liquid crystal display component of the present invention has the aforementioned liquid crystal alignment film. The liquid crystal display component of the present invention can be produced, 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 onto a substrate

[0251] The liquid crystal alignment agent of the present invention is applied to 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 component, if only a single-sided substrate is used, an opaque material 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, the 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] The method of coating the liquid crystal alignment agent on the substrate to form a film may include screen printing, lithography, flexographic printing, inkjet method or spray coating method, etc. Among them, the film forming method is preferably coating by inkjet method.

[0253] Step (2): calcining the coated liquid crystal alignment agent

[0254] Step (2) is a step of calcining the liquid crystal alignment agent applied on the substrate to form a film. After the liquid crystal alignment agent is applied 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 applied 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 device will be reduced, so the film thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm.

[0255] Step (3): Alignment treatment of the film obtained in step (2) Step (3) is to perform alignment treatment on the film obtained in step (2) as appropriate. In other words, in a horizontal alignment type liquid crystal display component such as an IPS mode or an FFS mode, the coating film is subjected to an alignment treatment to impart alignment capability. On the other hand, in a vertical alignment type liquid crystal display component such as a VA mode or a PSA mode, the formed coating film can be used directly as a liquid crystal alignment film, but the coating film can also be subjected to an alignment treatment to impart alignment capability. The alignment treatment of the liquid crystal alignment film can include a friction treatment method or a photo alignment treatment method, preferably a photo alignment treatment method. The photo alignment treatment method can include a method in which the surface of the above-mentioned film-like object is irradiated with radiation that has been deflected in a certain direction, and, as appropriate, preferably heated at a temperature of 150°C to 250°C to impart liquid crystal alignment (also referred to as liquid crystal alignment 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.

[0256] 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 alignment agent of the present invention can obtain a liquid crystal alignment film in which the variation (non-uniformity) of the liquid crystal alignment within the film surface is effectively suppressed even if the amount of light irradiation in the alignment treatment is reduced. When irradiating radiation, in order to improve the liquid crystal alignment, the substrate of the aforementioned film-like object can be heated at 50°C to 250°C while irradiating. The liquid crystal alignment film produced in this way can stably align the liquid crystal molecules in a certain direction. Secondly, the liquid crystal alignment film that has been irradiated with polarized radiation in the aforementioned method can be contact-treated with a solvent, or the liquid crystal alignment film that has been irradiated with radiation can be heat-treated.

[0257] 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.

[0258] Step (4): Making liquid crystal cells

[0259] Two liquid crystal alignment film substrates formed as described above are prepared, and liquid crystal is arranged between the two substrates arranged facing each other. For example, the following two methods can be cited. In the first method, the two substrates are arranged facing each other with a gap (cell gap) between them in a manner that the liquid crystal alignment films face each other. Then, the peripheral portions of the two substrates are bonded together with a sealant, and then the liquid crystal composition is injected and filled into the cell gap separated by the substrate surface and the sealant, and after it contacts the film surface, the injection hole is sealed.

[0260] The second method is a method called ODF (One Drop Fill). A sealant such as a UV-curable sealant is applied to a predetermined position of one of the two substrates on which a liquid crystal alignment film has been formed, and then a liquid crystal composition is dripped at multiple predetermined positions on the surface of the liquid crystal alignment film. Then, the other substrate is attached in a manner that the liquid crystal alignment films face 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 alignment 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.

[0261] If necessary, a polarizing plate can be attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display device. The polarizing plate attached to the outer surface of the liquid crystal cell can be a polarizing film called "H film" that stretches 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.

[0262] 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

[0263] Preparation of the blocked compound shown in formula (a-4)

[0264] Synthesis Example A-4-1

[0265] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 54.8 g (0.30 mol) of 4-chlorophthalic anhydride, 125 g of toluene, 36.4 g (0.36 mol) of triethylamine and 0.31 g (0.45×10 -3 1 mol) of bistriphenylphosphine dichloropalladium and heated to 85°C. Then, 45.7 g (0.30 mol) of 8-methyl-1-decyne was added dropwise to react. After the reaction was completed, the precipitated 8-methyl-decynyl phthalic anhydride and triethylamine hydrochloride were separated by solid-liquid separation, and washed with 70 g of propionic acid to dissolve the triethylamine hydrochloride, and the compound shown in the above formula (a-4-4) of Synthesis Example A-4-1 was obtained. Among them, the purity of the target product 8-methyl-decynyl phthalic anhydride is 65%.

[0266] Synthesis Example A-4-2

[0267] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 54.8 g (0.30 mol) of 4-chlorophthalic anhydride, 125 g of toluene, 36.4 g (0.36 mol) of triethylamine and 0.31 g (0.45×10 -3 1-ethynyl-4-nonylbenzene was added to the mixture, and the mixture was heated to 75°C. Then, 68.5 g (0.30 mol) of 1-ethynyl-4-nonylbenzene was added dropwise to react. After the reaction was completed, the precipitated 4-nonylbenzene-ethynylphthalic anhydride and triethylamine hydrochloride were separated by solid-liquid separation, and washed with 40 g of propionic acid to dissolve the triethylamine hydrochloride, and the compound shown in the above formula (a-4-8) of Synthesis Example A-4-2 was obtained. Among them, the purity of the target product 4-nonylbenzene-ethynylphthalic anhydride was 80%.

[0268] Synthesis Example A-4-3

[0269] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 400 ml of toluene, 54.6 ml of triethylamine (0.39 mol), 100 ml of 1-ethynyl-4-nonylbenzene (0.39 mol and density 0.89 g / cm 3 ) and 75 g of trimellitic anhydride chloride (0.36 mol). Then, 0.16 g of palladium acetate (0.78 mmol) was added, and after stirring at room temperature for 1 hour, 16.5 ml of triethylamine (0.12 mol) was added.

[0270] After the mixture is stirred for 2 hours, the solid obtained is filtered, washed with 250 ml of toluene, and suspended in 600 ml of ethyl acetate. The mixture is heated to reflux for 15 minutes, and then filtered and purified with a silica gel bed. Then, the filtrate is further concentrated in vacuo, the precipitate obtained is filtered, and washed with toluene. The solid obtained is vacuum dried to obtain the compound shown in the above formula (a-4-17) of Synthesis Example A-4-3. Among them, the purity of the target product 4-nonylbenzene-ethynyl trimellitic anhydride is 65%.

[0271] Synthesis Example A-4-4

[0272] A stirrer, a thermometer, an upward condenser tube and a nitrogen inlet tube are set on a four-necked conical flask with a volume of 500 ml. Then, 63.2 grams (0.30 mole) of chlorinated trimellitic anhydride, 125 grams of toluene, 36.4 grams (0.36 mole) of triethylamine and 0.31 grams (0.45 millimoles) of bistriphenylphosphine dichloropalladium are added, and heated to 75°C. Then, 45.7 grams (0.30 mole) of 8-methyl-1-decyne are added dropwise to react. After the reaction is completed, the precipitated 8-methyl-decynyl trimellitic anhydride and triethylamine hydrochloride are separated by solid-liquid separation, and washed with 40 grams of propionic acid to dissolve the triethylamine hydrochloride, and the compound shown in the above formula (a-4-13) of Synthesis Example A-4-4 can be obtained. Wherein, the purity of the target product 8-methyl-decynyl trimellitic anhydride is 80%.

[0273] Synthesis Example A-4-5

[0274] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 68.1 g (0.30 mol) of 4-bromophthalic anhydride, 125 g of toluene, 36.4 g (0.36 mol) of triethylamine and 0.31 g (0.45×10 -3 1 mol) of bistriphenylphosphine dichloropalladium and heated to 75°C. Then, 28.9 g (0.30 mol) of 3-methyl-1-hexyne was added dropwise to react. After the reaction was completed, the precipitated 3-methyl-hexynyl phthalic anhydride and triethylammonium bromide were separated by solid-liquid separation, and washed with 40 g of propionic acid to dissolve the triethylammonium bromide, and the compound shown in the above formula (a-4-2) of Synthesis Example A-4-5 was obtained. Among them, the purity of the target product 3-methyl-hexynyl phthalic anhydride is 80%.

[0275] Synthesis Example A-4-6

[0276] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 54.8 g (0.30 mol) of 4-chlorophthalic anhydride, 125 g of toluene, 36.4 g (0.36 mol) of triethylamine and 0.31 g (0.45×10 -3 100 g (0.1 mol) of bistriphenylphosphine dichloropalladium was added and heated to 75°C. Then, 56.5 g (0.30 mol) of 4-ethynylphenylpentyl ether was added dropwise to react. After the reaction was completed, the precipitated phenylpentyl ether ethynylphthalic anhydride and triethylamine hydrochloride were separated by solid-liquid separation and washed with 40 g of propionic acid to dissolve the triethylamine hydrochloride, and the compound shown in the above formula (a-4-11) of Synthesis Example A-4-6 was obtained. Among them, the purity of the target product phenylpentyl ether ethynylphthalic anhydride was 80%.

[0277] Synthesis Example A-4-7

[0278] A stirrer, a thermometer, an upward condenser and a nitrogen inlet were set on a 500 ml four-necked conical flask. Then, 68.1 g (0.30 mol) of 4-bromophthalic anhydride, 125 g of toluene, 36.4 g (0.36 mol) of triethylamine and 0.31 g (0.45×10 -3 100 g (0.1 mol) of bis(triphenylphosphine) dichloropalladium was added and heated to 75°C. Then, 37.3 g (0.30 mol) of nonyne was added dropwise to react. After the reaction was completed, the precipitated nonynylphthalic anhydride and triethylammonium bromide were separated by solid-liquid separation and washed with 40 g of propionic acid to dissolve the triethylammonium bromide, thereby obtaining the compound shown in the above formula (a-4-3) of Synthesis Example A-4-7. The purity of the target product nonynylphthalic anhydride was 80%.

[0279] Preparation of diamine compound (a2-1)

[0280] Synthesis Example A2-1-1

[0281] Step 1:

[0282] 10.74 g (46.5 mmol) of 4-hydroxy-4′-nitrodiphenyl ether was dissolved in 40.0 g of DMF, 9.76 g (69.7 mmol) of potassium carbonate was added, and 40.0 g of DMF solution containing 17.15 g (69.7 mmol) of β-bromo-4-nitrophenyl ether was dropped into the solution to form a mixed solution.

[0283] The mixed solution was stirred at 70°C for 5 hours, 200 g of water was added, the precipitate was filtered, and washed with 200 g of MeOH. After the precipitate was dried under reduced pressure, 12.91 g (32.6 mmol) of 4-nitro-4′-(2-(4-nitrophenoxy)ethoxy)-1,1′-diphenyl ether was obtained.

[0284] The reaction of the aforementioned step 1 is shown in the following reaction formula.

[0285]

[0286] Step 2:

[0287] 5.19 g (13.1 mmol) of 4-nitro-4′-(2-(4-nitrophenoxy)ethoxy)-1,1′-diphenyl ether was dissolved in 100.0 g of tetrahydrofuran, and 0.1 g (5 weight percent) of palladium-carbon was added. After stirring at room temperature for 1 hour under hydrogen, the reaction solution was dissolved in 1200.0 g of tetrahydrofuran, and the catalyst was removed by filtration. Then, the filtrate was concentrated, and the precipitated solid was washed with 200.0 g of heptane. After drying, 2.86 g (8.5 mmol) of the diamine compound (a2-1-1) of Synthesis Example A2-1-1 shown in the aforementioned formula (A21-7) was obtained.

[0288] The reaction of the aforementioned step 2 is shown in the following reaction formula.

[0289]

[0290] Synthesis Example A2-1-2

[0291] The preparation of the diamine compound (a2-1-2) of Synthesis Example A2-1-2 is carried out using the same method and reactant molar ratio as the preparation method of the aforementioned diamine compound (a2-1-1), except that the preparation of the diamine compound (a2-1-2) is carried out using 2-(4-hydroxy-phenoxy)-5-nitropyridine in step 1. Substitute 4-hydroxy-4′-nitrodiphenyl ether with α-chloro-1-ethoxy-4-nitrobenzene Substitute β-bromo-4-nitrophenyl ether to obtain a structure of Then, it is substituted for 4-nitro-4′-(2-(4-nitrophenoxy)ethoxy)-1,1′-diphenyl ether in step 2 to obtain the diamine compound (a2-1-2) of synthesis example A2-1-2 shown in the aforementioned formula (A21-24).

[0292] Synthesis Example A2-1-3

[0293] The preparation of the diamine compound (a2-1-3) of Synthesis Example A2-1-3 is carried out using the same method and reactant molar ratio as the preparation method of the aforementioned diamine compound (a2-1-1), except that the preparation of the diamine compound (a2-1-3) is carried out in step 1 using 1-(3-chloro-cyclohexyl)-4-nitrobenzene Substitute β-bromo-4-nitrophenyl ether to obtain a structure of Then, it is substituted for 4-nitro-4′-(2-(4-nitrophenoxy)ethoxy)-1,1′-diphenyl ether in step 2 to obtain the diamine compound (a2-1-3) of synthesis example A2-1-3 shown in the above formula (A21-11).

[0294] Preparation of polymer (A)

[0295] Synthesis Example A-1-1

[0296] 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, 4.2 g (0.0125 mol) of the diamine compound (a2-1-1) obtained in Synthesis Example A2-1-1, 4.98 g (0.0125 mol) of the diamine compound (a2-2-1-1) shown in formula (A22-1-7), 1.24 g (0.005 mol) of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (a2-2-2-1), 6.94 g (0.02 mol) of the diamine compound (a2-2-3-1) shown in formula (A22-3-1) and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) were added, and stirred at room temperature until dissolved. Next, 8.97 g (0.04 mol) of compound (a1-1-1) and 20 g of NMP were added and reacted at room temperature for 2 hours. Then, 4.97 g (0.02 mol) of 4-phenylethynylphthalic anhydride (a-4-8; manufactured by Tokyo Chemical Industry Co., Ltd.) was added and reacted overnight at room temperature. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer, the obtained polymer was filtered, and the steps of washing and filtering were repeated three times with methanol. After that, the product was placed in a vacuum oven and dried at a temperature of 60°C to obtain the polymer (A-1-1) of Synthesis Example A-1-1, the formula of which is shown in Table 1.

[0297] Synthesis Example A-1-2 to Synthesis Example A-1-38 and Synthesis Comparative Examples A-1-39 to Synthesis Example A-1-38

[0298] Synthesis Examples A-1-2 to A-1-38 and Comparative Synthesis Examples A-1-39 to A-1-38 use the same preparation method as the method for making the polymer (A-1-1) in Synthesis Example A-1-1, with the difference being that Synthesis Examples A-1-2 to A-1-38 and Comparative Synthesis Examples A-1-39 to A-1-38 change the type and amount of raw materials in the polymer, and their formulas are shown in Tables 1 and 2, respectively, and are not described in detail here.

[0299] Synthesis Example A-2-1 to Synthesis Example A-2-6

[0300] Synthesis Examples A-2-1 to A-2-6 use the same preparation method as the preparation method of the polymer (A-1-1) of Synthesis Example A-1-1, except that the types and amounts of raw materials in the polymers are changed in Synthesis Examples A-2-1 to A-2-6, and their formulations are shown in Table 3, which are not described in detail here. Among them, Tables 1 to 3 use the same types of raw materials.

[0301]

[0302]

[0303]

[0304] Preparation of polymer (B)

[0305] Synthesis Example B-1-1

[0306] A nitrogen inlet, agitator, a condenser and a thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, 9.95 grams (0.05 mole) of diamine compound (B2-1) and 80 grams of NMP are added, and stirred at room temperature until dissolved. Next, 9.8 grams (0.05 mole) of tetracarboxylic dianhydride compound (B1-1) and 20 grams of NMP are added, and reacted 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, filter the obtained polymer, and repeat the steps of washing and filtering with methanol three times. Afterwards, the product is placed in a vacuum oven and dried at a temperature of 60°C to obtain the polymer (B-1-1) of Synthesis Example B-1-1, and its formula is shown in Table 4.

[0307] Synthesis Example B-1-2 to Synthesis Example B-2-3

[0308] Synthesis Examples B-1-2 to B-2-3 use the same preparation method as the preparation method of the polymer (B-1-1) in Synthesis Example B-1-1, the difference is that Synthesis Examples B-1-2 to B-2-3 change the type and amount of raw materials in the polymer, and their formulas are shown in Table 4, which are not further described here.

[0309] Table 4

[0310]

[0311]

[0312] Preparation of liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component

[0313] Example 1

[0314] 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-1-3) prepared in Synthesis Example B-1-3, 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.

[0315] 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 are respectively in 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.

[0316] 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 film 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.

[0317] 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 alignment 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 component of Example 1. The obtained liquid crystal display component is evaluated in the following evaluation method, and the results are shown in Table 3, wherein the detection method of the real-time flicker after driving will be described later.

[0318] Examples 2 to 46 and Comparative Examples 1 to 4

[0319] Examples 2 to 46 and Comparative Examples 1 to 4 use the same preparation method for the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component as Example 1. The difference is that Examples 2 to 46 and Comparative Examples 1 to 4 change the type and usage of raw materials in the liquid crystal alignment agent. Their formulas and evaluation results are shown in Tables 5 and 6, respectively, and are not further described here.

[0320]

[0321] Table 6

[0322]

[0323] Evaluation method

[0324] Real-time flicker after driving

[0325] The prepared liquid crystal display component is placed between two polarizing plates with polarization axes arranged in a vertically crossed manner, and the LED backlight is lit without applying voltage. The configuration angle of the liquid crystal display component is adjusted to minimize the brightness of the transmitted light. Then, an AC voltage with a frequency of 30 Hz is applied to the liquid crystal display component, and the VT curve (voltage-transmittance curve) is measured at the same time. The AC voltage with a relative transmittance of 23% is calculated as the driving voltage.

[0326] The method for measuring the flicker after driving is to turn off the lit LED backlight under the temperature condition of the liquid crystal display component at 23°C, place it in a dark place for 72 hours, and then light it again. At the same time as the backlight starts to light up, an AC voltage with a relative transmittance of 23% and a frequency of 30Hz is applied to the liquid crystal display component for 60 minutes, and the amplitude of the flicker is tracked. The flicker amplitude is the brightness value of the liquid crystal display component passing through two polarizing plates and between them using a data acquisition / data recording switching device 34970A (manufactured by Agilent technologies) connected to a photodiode and an IV conversion amplifier. The flicker (FL) is calculated according to the following formula (III). The lower the flicker, the better the quality of the liquid crystal display component made with this liquid crystal alignment agent.

[0327]

[0328] In formula (III), z is the brightness value read when the device 34970A is driven by an AC voltage of 30 Hz with a relative transmittance of 23%.

[0329] ※: FL<2%.

[0330] ◎:3%>FL≥2%.

[0331] ○: 4%>FL≥3%.

[0332] △: 5%>FL≥4%.

[0333] ×: FL≥5%.

[0334] From the results of Tables 5 and 6, it can be seen that if the main chain end of the polymer (A) of the liquid crystal alignment agent of the present invention does not have a structure as shown in formula (a-1) or formula (a-2), the obtained liquid crystal display device has too high a real-time flicker after driving. When the main chain end of the polymer (A) has a structure as shown in formula (a-1) or formula (a-2), if the M of formula (a-1) and formula (a-2)2 represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, and M of formula (a-3) 3 is a group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, the real-time flicker of the obtained liquid crystal display component after driving can be further reduced; if M of formula (a-1) and formula (a-2) 2 represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms, and M in formula (a-3) 3 The group is selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms. The real-time flicker of the liquid crystal display component after driving can be further reduced.

[0335] Secondly, when the amount of the compound represented by formula (a-4) as the end-capping compound is 2 mol% to 60 mol%, the prepared liquid crystal alignment film can effectively reduce the real-time flicker of the liquid crystal display component after driving.

[0336] Furthermore, when the diamine component (A2) of the polymer (A) contains at least the diamine compound (a2-1) shown in the above formula (A21), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving. Among them, when the usage amount of the diamine compound (a2-1) is 5 mol% to 60 mol%, the prepared liquid crystal alignment film can more effectively reduce the real-time flicker of the liquid crystal display component after driving.

[0337] When polymer (A) contains a structure as shown in at least one of formula (a-6), formula (a-7) and formula (a-8), the liquid crystal alignment film prepared by the liquid crystal alignment agent can further reduce the real-time flicker of the liquid crystal display component after driving.

[0338] 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 and its preparation method, liquid crystal alignment film and liquid crystal display component 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 to this. Without departing from the spirit and scope of the present invention, the liquid crystal alignment agent and its preparation method, liquid crystal alignment film and liquid crystal display component of the present invention may also use other compounds, compositions, reaction conditions, processes, analysis methods or instruments.

[0339] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Include: A polymer (A), wherein the polymer (A) is at least one polymer selected from a polyimide precursor and a polyimide, wherein the polymer main chain ends have structures represented by the following formulas (a-1) and (a-2): In formula (a-1) and formula (a-2), M1 represents a single bond or a carbonyl group; M2 represents a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group as shown in the following formula (a-3); In formula (a-3), M3 is a group selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms; and A solvent (C).

2. The liquid crystal alignment agent according to claim 1, characterized in that: M2 in formula (a-1) and formula (a-2) represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, and M3 in the aromatic hydrocarbon group represented by formula (a-3) is a group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

3. The liquid crystal alignment agent according to claim 1 or 2, characterized in that: M2 in formula (a-1) and formula (a-2) represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms, and M3 in the aromatic hydrocarbon group represented by formula (a-3) is a group selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.

4. The liquid crystal alignment agent according to claim 1, characterized in that: The polymer (A) comprises a structure represented by the following formula (a-5): *--R1-R4-R2-R6-R5-R7-R3-*(a-5) In formula (a-5), R1, R2 and R3 each independently represent a divalent organic group of a benzene ring or a pyridine ring; R4 represents an oxygen atom or a sulfur atom; R5 represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 30 carbon atoms; R6 and R7 each independently represent a single bond, an oxygen atom, a sulfur atom or -NR8-, wherein at least one of R6 and R7 represents an oxygen atom, a sulfur atom or -NR8-, and R8 represents a hydrogen atom or a methyl group; when any one of R1, R2 and R3 is a pyridine ring, R6 and R7 do not represent a single bond; "*" represents a bonding position.

5. The liquid crystal alignment agent according to claim 1, characterized in that: The polymer (A) comprises a structure represented by at least one of the following formulas (a-6), (a-7) and (a-8): In formula (a-6), Z7 represents an oxygen atom or a sulfur atom; Z3 and Z4 each independently represent an alkylene group having 1 to 3 carbon atoms; Z1 and Z2 each independently represent a single bond, -O-, -S-, -OC O- or -CO O-; and Z5 and Z6 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a protecting group substituted by a hydrogen atom by heat, wherein at least one of Z5 and Z6 represents a protecting group substituted by a hydrogen atom by heat; In formula (a-7), A1, A2, A3 and A4 each independently represent a monovalent hydrocarbon group, and A1, A2, A3 and A4 are the same or different; A5 each independently represent a divalent hydrocarbon group, and A5 are the same or different; a represents an integer from 1 to 10; *-D1-D3-D5-D4-D2-* (a-8) In formula (a-8), D1 and D2 represent a divalent aromatic ring group, the ring part of the aromatic ring group may have a substituent, and D1 and D2 are the same; D3 represents -ND 31 -, and D 31 represents a protecting group substituted by a hydrogen atom by heat; D4 represents a single bond, an oxygen atom or a sulfur atom; D5 represents a divalent group having at least one of a chain hydrocarbon structure having 1 to 15 carbon atoms and an alicyclic hydrocarbon structure having 3 to 15 carbon atoms; when D4 is a sulfur atom, the carbon number of D5 is greater than and equal to 2.

6. A liquid crystal alignment film, characterized in that: The liquid crystal alignment agent is formed by using the liquid crystal alignment agent as claimed in any one of claims 1 to 5.

7. A liquid crystal display component, characterized in that: It comprises the liquid crystal alignment film as claimed in claim 6.

8. A method for preparing a liquid crystal alignment agent, characterized in that: Include: A polymer (A) and a solvent (C) are mixed to prepare the liquid crystal alignment agent, wherein the polymer (A) is an imidized polyimide precursor obtained by a polymerization reaction of a tetracarboxylic acid derivative component (A1) and a diamine component (A2), and During and / or after the polymerization reaction, adding a compound represented by the following formula (a-4) to a reaction solution; In formula (a-4), M1 represents a single bond or a carbonyl group; M2 represents a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group as shown in formula (a-3); In formula (a-3), M3 is a group selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

9. The method for preparing a liquid crystal alignment agent according to claim 8, characterized in that: M2 in formula (a-4) represents a saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms or an aromatic hydrocarbon group as shown in formula (a-3): In formula (a-3), M3 is a group selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

10. The method for preparing a liquid crystal alignment agent according to claim 8, characterized in that: M2 in formula (a-4) represents a saturated aliphatic hydrocarbon group having 1 to 3 carbon atoms or an aromatic hydrocarbon group as shown in formula (a-3): In formula (a-3), M3 is a group selected from a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.

11. The method for preparing a liquid crystal alignment agent according to claim 8, wherein: Based on a usage amount of the diamine component (A2) of 100 mol%, a usage amount of the compound represented by formula (a-4) is 2 mol% to 60 mol%.

12. The method for preparing a liquid crystal alignment agent according to claim 8, wherein: The diamine component (A2) comprises at least a diamine compound (a2-1) represented by the following formula (A21): H2N-R1-R4-R2-R6-R5-R7-R3-NH2 (A21) In formula (A21), R1, R2 and R3 each independently represent a divalent organic group of a benzene ring or a pyridine ring; R4 represents an oxygen atom or a sulfur atom; R5 represents a divalent chain hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon group having 3 to 30 carbon atoms; R6 and R7 each independently represent a single bond, an oxygen atom, a sulfur atom or -NR8-, wherein at least one of R6 and R7 represents an oxygen atom, a sulfur atom or -NR8-, and R8 represents a hydrogen atom or a methyl group; when any one of R1, R2 and R3 is a pyridine ring, R6 and R7 do not represent a single bond.

13. The method for preparing a liquid crystal alignment agent according to claim 12, characterized in that: Based on a usage amount of the diamine component (A2) of 100 mol%, a usage amount of the diamine compound (a2-1) as shown in formula (A21) is 5 mol% to 60 mol%.

14. The method for preparing a liquid crystal alignment agent according to claim 8, characterized in that: The diamine component (A2) comprises at least one of a diamine compound (a2-2-1) represented by the following formula (A22-1), a diamine compound (a2-2-2) represented by the following formula (A22-2), and a diamine compound (a2-2-3) represented by the following formula (A22-3): In formula (A22-1), Z7 represents an oxygen atom or a sulfur atom; Z3 and Z4 each independently represent an alkylene group having 1 to 3 carbon atoms; Z1 and Z2 each independently represent a single bond, -O-, -S-, -OCO- or -COO-; and Z5 and Z6 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a protecting group substituted by a hydrogen atom by heat, wherein at least one of Z5 and Z6 represents a protecting group substituted by a hydrogen atom by heat; In formula (A22-2), A1, A2, A3 and A4 each independently represent a monovalent hydrocarbon group, and A1, A2, A3 and A4 are the same or different; A5 each independently represent a divalent hydrocarbon group, and A5 are the same or different; a represents an integer from 1 to 10; H2N-D1-D3-D5-D4-D2-NH2 (A22-3) In formula (A22-3), D1 and D2 represent a divalent aromatic ring group, the ring part of the aromatic ring group may have a substituent, and D1 and D2 are the same; D3 represents -ND 31 -, and D 31 represents a protecting group substituted by a hydrogen atom by heat; D4 represents a single bond, an oxygen atom or a sulfur atom; D5 represents a divalent group having at least one of a chain hydrocarbon structure having 1 to 15 carbon atoms and an alicyclic hydrocarbon structure having 3 to 15 carbon atoms; when D4 is a sulfur atom, the carbon number of D5 is greater than or equal to 2.

15. The method for preparing a liquid crystal alignment agent according to claim 14, characterized in that: Based on a usage amount of the diamine component (A2) of 100 mol%, a usage amount of the diamine compound (a2-2-1) shown in formula (A22-1), a usage amount of the diamine compound (a2-2-2) shown in formula (A22-2), and a total usage amount of the diamine compound (a2-2-3) shown in formula (A22-3) is 2 mol% to 95 mol%.

16. A liquid crystal alignment film, formed by using a liquid crystal alignment agent, characterized in that: The liquid crystal alignment agent is prepared by the preparation method according to any one of claims 8 to 15.

17. A liquid crystal display component, characterized in that: Comprising a liquid crystal alignment film as described in claim 16.

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