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

Abstract

This invention provides a liquid crystal alignment agent, a liquid crystal alignment film formed using this liquid crystal alignment agent, and a liquid crystal display element comprising this liquid crystal alignment film. The liquid crystal alignment agent of this invention comprises a polymer component (A) and a solvent (B). The polymer component (A) comprises a first polymer (A1), wherein the first polymer (A1) is selected from at least one polymer selected from the group consisting of polyimide precursors and amide polymers of polyimide precursors, and the polyimide precursor of the first polymer (A1) has a specific structure. The liquid crystal display element comprising the liquid crystal alignment film formed using this liquid crystal alignment agent exhibits good high and low temperature shock contrast.

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, and more particularly to a liquid crystal alignment agent, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display element comprising the liquid crystal alignment film. Prior Technology

[0002] Liquid crystal display (LCD) elements are widely used as display components in personal computers, smartphones, mobile phones, and television receivers. An LCD element may include a liquid crystal layer sandwiched between a substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of the liquid crystal molecules in the liquid crystal layer, and a thin-film transistor (TFT) that switches the electronic signals supplied to the pixel electrodes. Regarding the driving method of the liquid crystal molecules, known methods include longitudinal electric field methods such as TN (Twisted Nematic) and VA (Vertical Alignment), and transverse electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching).

[0003] Currently, the most widely used liquid crystal alignment film in industry is produced by rubbing the surface of a film formed on an electrode substrate, consisting of polyamide and / or polyimide obtained through amide modification, with a cloth such as cotton, nylon, or polyester along one direction. Friction treatment is a simple and highly productive industrial method. However, with the increasing performance, precision, and size of liquid crystal display elements, the alignment film surface is scratched by dust, mechanical force, and static electricity generated during friction treatment, leading to various problems such as inhomogeneity within the alignment surface. As an alternative to friction treatment, photoalignment methods are known, which impart alignment capability to the liquid crystal by irradiating it with polarized radiation. Regarding photoalignment methods, Japanese Patent Application Publication No. Hei 9-297313 discloses methods utilizing photoisomerization reactions, photocrosslinking reactions, or photodecomposition reactions.

[0004] However, with the widespread adoption of fast charging technology in smartphones, tablets, and other electronic products, charging voltage and current have increased by more than double compared to the past, causing a rapid rise in temperature during charging. Coupled with the increasingly frequent use of electronic products today, these products undergo frequent cycles of rapid temperature increases and decreases. These high-frequency temperature fluctuations inevitably affect the display quality of electronic products.

[0005] Experiments have shown that such high and low temperature shocks will affect the alignment structure stability of conventional liquid crystal alignment films prepared by photoalignment, thereby causing contrast variations in liquid crystal display elements made using such liquid crystal alignment films, which is related to a decrease in display quality.

[0006] The purpose of this invention is to provide a liquid crystal alignment film with high high and low temperature shock contrast, a liquid crystal alignment agent for obtaining the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film.

[0007] In order to achieve the above-mentioned objectives, the inventors of this invention conducted extensive research and discovered that liquid crystal alignment films formed by liquid crystal alignment agents of polymers that meet specific conditions are highly effective in achieving the above objectives, thus completing this invention. Summary of the Invention

[0008] In view of this, one aspect of the present invention is to provide a liquid crystal alignment agent comprising a first polymer (Al) having a specific structure. The liquid crystal alignment film formed using this liquid crystal alignment agent can exhibit high high and low temperature shock contrast.

[0009] Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed using the above-mentioned liquid crystal alignment agent.

[0010] Another aspect of the present invention is to provide a liquid crystal display element comprising the liquid crystal alignment film described above.

[0011] According to the above-described embodiments of the present invention, a liquid crystal alignment agent is provided. The liquid crystal alignment agent of the present invention comprises a polymer component (A) and a solvent (B). The polymer component (A) comprises a first polymer (A1), wherein the first polymer (A1) is selected from at least one group consisting of polyimide precursors and amide-modified polymers of polyimide precursors. The polyimide precursor of the first polymer (A1) comprises the structure shown in formula (I): (I).

[0012] In formula (I), X1 is selected from at least one of the groups consisting of structures shown in formulas (I-1) to (I-7), where "*" represents a bond position; X2 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7) In formula (I-1), X11, X12, X13, and X14 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 organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. In formula (I-7), X15 and X16 independently represent a hydrogen atom or a methyl group.

[0013] In equation (I), A1 and A2 independently represent divalent organic groups as shown in the following structures, and A1 and A2 do not have the same structure; "*" represents the bonding position; In the structure shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, methyl, hydroxyl, or methoxy group.

[0014] In formula (I), Y11 and Y11' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y12 and Y12' independently represent -O-, -S-, -OCO-, or -COO-; Y13 and Y13' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y11, Y11', Y13, and Y13' are not all single bonds; Z1 represents the structure shown in formula (Z1-1) below: (Z1-1). In formula (Z1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

[0015] According to some embodiments of the present invention, X1 above represents the structure shown in formula (I-1-1), and "*" represents the bond position: (I-1-1).

[0016] According to some embodiments of the present invention, Y13 and Y13' represent single bonds.

[0017] According to some embodiments of the present invention, A1 and A2 respectively independently represent divalent organic groups as shown in the following structures, and A1 and A2 do not have the same structure. In the structure shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, methyl, hydroxyl, or methoxy group.

[0018] According to some embodiments of the present invention, Z1 above represents the structure shown in formula (Z1-1-1): (Z1-1-1). In formula (Z1-1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

[0019] According to some embodiments of the present invention, the polymer component (A) further comprises a second polymer (A2), wherein the second polymer (A2) is selected from at least one of the group consisting of a polyimide precursor and a polyimide polymer of the polyimide precursor, and the second polymer (A2) does not contain the structure shown in formula (I).

[0020] According to some embodiments of the present invention, the polyimide precursor of the second polymer (A2) is obtained by reacting a tetracarboxylic dianhydride component (a2) and a diamine component (b2), wherein the diamine component (b2) comprises a diamine compound (b2-1) having a nitrogen-containing structure, and the nitrogen atom structure in the diamine compound (b2-1) having a nitrogen-containing structure is selected from at least one of the group consisting of nitrogen-containing heterocycles, secondary amine groups and tertiary amine groups.

[0021] According to some embodiments of the present invention, the above-mentioned liquid crystal alignment agent is configured to prepare a liquid crystal alignment film used in a photoalignment process.

[0022] Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed using the above-mentioned liquid crystal alignment agent.

[0023] Another aspect of the present invention is to provide a liquid crystal display element comprising the liquid crystal alignment film described above.

[0024] Based on the above, the present invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element, wherein the first polymer (A1) in the polymer component (A) contains the structure shown in formula (I), thereby enabling the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent to have good high and low temperature shock contrast. Simple Explanation of the Diagram

[0025] (none) Implementation

[0026] Liquid crystal alignment agent

[0027] In view of this, one aspect of the present invention provides a liquid crystal alignment agent comprising a polymer component (A) and a solvent (B); wherein the polymer component (A) comprises a first polymer (A1), and the first polymer (A1) is selected from at least one of the group consisting of polyimide precursors and amided polymers formed from polyimide precursors, characterized in that the polyimide precursor of the first polymer (A1) comprises the structure shown in formula (I). The liquid crystal alignment film formed using this liquid crystal alignment agent can effectively improve the high and low temperature shock contrast of liquid crystal display elements.

[0028] Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed using the above-mentioned liquid crystal alignment agent.

[0029] Another aspect of the present invention is to provide a liquid crystal display element comprising the aforementioned liquid crystal alignment film, which has a high high and low temperature shock contrast ratio.

[0030] Polymer component (A)

[0031] First polymer (A1)

[0032] The first polymer (A1) in this embodiment of the invention is selected from at least one polymer in the group consisting of polyimide precursors and polyimide polymers of polyimide precursors, wherein the polyimide precursors include polyamide, polyamide esters or combinations thereof.

[0033] The first polymer (A1) in this embodiment of the invention may be selected from at least one polymer in the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (b1), and a amide polymer of the polyimide precursor. For example, the first polymer (A1) is a polyimide precursor having a amide precursor structure such as polyamide acid and polyamide ester, or the first polymer (A1) is an amide polymer (i.e., polyimide) formed from the above-mentioned polyimide precursor, or the first polymer (A1) comprises the above-mentioned polyimide precursor and the above-mentioned amide polymer.

[0034] The polyimide precursor of the first polymer (A1) may contain the structure shown in formula (I): (I).

[0035] In formula (I), X1 represents at least one of the groups consisting of the structures shown in formulas (I-1) to (I-7), where "*" represents a bond position; X2 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7) In formula (I-1), X11, X12, X13, and X14 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 organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. In formula (I-7), X15 and X16 independently represent a hydrogen atom or a methyl group.

[0036] In one embodiment, X1 above represents the structure shown by equations (I-1-1) to (I-1-6): (I-1-1) (I-1-2) (I-1-3) (I-1-4) (I-1-5) (I-1-6). In equations (I-1-1) to (I-1-6), "*" represents the location of the bond.

[0037] In formula (I), X1 preferably represents the structure shown in formula (I-1), more preferably the structure shown in formula (I-1-1) or formula (I-1-6), and even more preferably the structure shown in formula (I-1-1). When X1 represents the structure shown in formula (I-1), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has better high and low temperature shock contrast (i.e., higher high and low temperature shock contrast). When X1 represents the structure shown in formula (I-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has even better high and low temperature shock contrast (i.e., even higher high and low temperature shock contrast).

[0038] In equation (I), A1 and A2 independently represent divalent organic groups as shown in the following structures, and A1 and A2 do not have the same structure; "*" represents the bonding position; . In the structure shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, methyl, hydroxyl, or methoxy group.

[0039] In some embodiments, A1 and A2 preferably each independently represent a divalent organic group as shown in the following structures, and A1 and A2 do not have the same structure. When A1 and A2 each independently represent a divalent organic group as shown in the following structures, the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has better high and low temperature shock contrast. In the structure shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, methyl, hydroxyl, or methoxy group.

[0040] In formula (I), Y11 and Y11' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y12 and Y12' independently represent -O-, -S-, -OCO- or -COO-; Y13 and Y13' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y11, Y11', Y13 and Y13' are not all single bonds at the same time.

[0041] In some embodiments, Y13 and Y13' preferably represent single bonds. When Y13 and Y13' represent single bonds, the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has better high and low temperature shock contrast.

[0042] Z1 represents the structure shown in equation (Z1-1): (Z1-1). In formula (Z1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

[0043] In some embodiments, Z1 represents the structure shown in equation (Z1-1-1): (Z1-1-1). In formula (Z1-1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

[0044] When Z1 represents the structure shown in formula (Z1-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has better high and low temperature shock contrast.

[0045] When the first polymer (A1) does not contain the structure shown in Formula (I), the high and low temperature shock contrast of the liquid crystal display element containing the liquid crystal alignment film formed therefrom is poor (that is, the high and low temperature shock contrast is too low), resulting in poor display quality.

[0046] When X1 in the structure shown in formula (I) is not selected from at least one of the groups consisting of the structures shown in formulas (I-1) to (I-7), the high and low temperature shock contrast of the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent is poor (that is, the high and low temperature shock contrast is too low), resulting in poor display quality of the liquid crystal display element.

[0047] When the group between the two NH in the structure shown in formula (I) is not -A 1-Y 13-Y 12-Y 11-Z 1-Y 11'-Y 12'-Y 13'-A 2-, the high and low temperature shock contrast of the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent is poor.

[0048] The first polymer (A1) in this embodiment of the invention may be selected from at least one polymer in the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (b1), and a amide polymer of the polyimide precursor. For example, the first polymer (A1) is a polyimide precursor having a amide precursor structure such as polyamide acid and polyamide ester, or the first polymer (A1) is an amide polymer (i.e., polyimide) formed from the above-mentioned polyimide precursor, or the first polymer (A1) comprises the above-mentioned polyimide precursor and the above-mentioned amide polymer.

[0049] It is worth noting that the structure shown in formula (I) above is formed by the reaction of the following alicyclic tetracarboxylic dianhydride (a1-1) with the following diamine compound (b1-1).

[0050] Furthermore, the polyimide precursor of the first polymer (A1) may further include, but is not limited to, other structural units other than those of formula (I) formed by any one of the tetracarboxylic dianhydrides (a1) and any one of the diamines (b1) described later, which will not be elaborated here.

[0051] Tetracarboxylic dianhydride component (a1)

[0052] In addition to tetracarboxylic dianhydride compounds, the tetracarboxylic dianhydride component (a1) can also use tetracarboxylic dianhydride derivatives such as tetracarboxylic dihalides, tetracarboxylic dialkyl esters, or tetracarboxylic dialkyl ester dihalides. The tetracarboxylic dianhydride component (a1) can be used alone or in combination with multiple tetracarboxylic dianhydride compounds or their derivatives.

[0053] Alicyclic tetracarboxylic dianhydride (a1-1)

[0054] In some embodiments of the present invention, the tetracarboxylic dianhydride component (a1) comprises an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof represented by formula (A11): (A11).

[0055] The alicyclic tetracarboxylic dianhydride or its derivatives shown in formula (A11) can be composed of a single tetracarboxylic dianhydride compound or its derivative, or a plurality of tetracarboxylic dianhydride compounds or their derivatives. The alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11) can, for example, contain at least one carboxyl group bonded to an alicyclic structure, obtained by intramolecular dehydration of the four carboxyl groups. However, none of these four carboxyl groups are bonded to an aromatic ring. Alternatively, it does not need to be composed solely of an alicyclic structure; a portion of it may also have a chain hydrocarbon structure or an aromatic ring structure. Aromatic tetracarboxylic dianhydrides are, for example, obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring. However, aromatic tetracarboxylic dianhydrides do not need to be composed solely of an aromatic ring structure; a portion of it may also have a chain hydrocarbon structure or an alicyclic structure. Acyclic alicyclic tetracarboxylic dianhydrides can, for example, be obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, acyclic aliphatic tetracarboxylic dianhydrides do not necessarily have to be composed solely of chain hydrocarbon structures; a portion of them may also have alicyclic or aromatic ring structures.

[0056] In equation (A11), X1 is selected from at least one of the groups consisting of the structures shown in equations (I-1) to (I-7), and "*" represents the bond position. (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7).

[0057] In formula (I-1), X11, X12, X13, and X14 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 organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. In formula (I-7), X15 and X16 independently represent a hydrogen atom or a methyl group.

[0058] In some embodiments of the present invention, the structure shown in formula (I-1) of X1 is selected from the structures shown in formulas (I-1-1) to (I-1-6), and "*" represents the bond position: (I-1-1) (I-1-2) (I-1-3) (I-1-4) (I-1-5) (I-1-6).

[0059] Preferably, X1 represents the structure shown in formula (I-1-1). When X1 represents the structure shown in formula (I-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has a higher high and low temperature shock contrast.

[0060] In some embodiments of the present invention, the total amount of the tetracarboxylic dianhydride component (a1) is 100 mol, and the amount of the alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11) is 30 to 100 mol, preferably 40 to 100 mol, and more preferably 50 to 100 mol.

[0061] When the tetracarboxylic acid dianhydride component (a1) does not contain the alicyclic tetracarboxylic acid dianhydride (a1-1) shown in formula (A11), the liquid crystal display element formed by the liquid crystal alignment film containing this liquid crystal alignment agent is prone to poor display quality due to low contrast caused by high and low temperature shocks.

[0062] Other tetracarboxylic dianhydrides (a1-2)

[0063] In some embodiments of the present invention, the tetracarboxylic dianhydride component (a1) further comprises other tetracarboxylic dianhydrides (a1-2).

[0064] In some embodiments of the present invention, other tetracarboxylic dianhydrides (a1-2) comprise tetracarboxylic dianhydride compounds and their derivatives as shown in formula (A12): (A12).

[0065] In equation (A12), X 1' represents the structure shown in equations (A12-1) to (A12-32), where "*" represents the bond position. (A12-1) (A12-2) (A12-3) (A12-4) (A12-5) (A12-6) (A12-7) (A12-8) (A12-9) (A12-10) (A12-11) (A12-12) (A12-13) (A12-14) (A12-15) (A12-16) (A12-17) (A12-18) (A12-19) (A12-20) (A12-21) (A12-22) (A12-23) (A12-24) (A12-25) (A12-26) (A12-27) (A12-28) (A12-29) (A12-30) (A12-31) (A12-32).

[0066] In formula (A12-1), a1 represents 1 to 12. In formula (A12-5), X11' represents a single bond, -O-, -CO-, -COO-, phenyl, sulfonyl, or amide group, and a1 represents 0 or 1. In formula (A12-6), X11' and X12' independently represent a single bond, -O-, -CO-, -COO-, phenyl, sulfonyl, or amide group, and multiple X12's may be the same or different from each other, and a1 represents 0 or 1. In formula (A12-11), a1 represents 2 to 6. In formula (A12-13), a1 represents 1 to 2. In formulas (A12-14), X 13' 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 containing a fluorine atom and having 1 to 6 carbon atoms, or a phenyl group, and multiple X 13's may be the same or different from each other. From the viewpoint of liquid crystal alignment, it is preferable that X 13' represents a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

[0067] In some embodiments, the aforementioned formulas (A12-5) and (A12-6) may include, but are not limited to, the structures shown below: .

[0068] The other tetracarboxylic dianhydrides (a1-2) mentioned above can be used alone or in combination. In some embodiments, based on the total amount of tetracarboxylic dianhydride component (a1) used being 100 mol, the amount of the other tetracarboxylic dianhydrides (a1-2) used can be from 0 mol to 70 mol, preferably from 0 mol to 60 mol, and more preferably from 0 mol to 50 mol.

[0069] Diamine component (b1)

[0070] The diamine component (b1) of the present invention may include diamine compound (b1-1), diamine compound (b1-2), diamine compound (b1-3) and other diamine compounds (b1-4).

[0071] Diamine compound (b1-1)

[0072] The diamine component (b1) of this invention comprises a diamine compound (b1-1) as shown in formula (IV): (IV).

[0073] In equation (IV), the definitions of A1, A2, Y11, Y11', Y12, Y12', Y13, Y13' and ring Z1 are as described above.

[0074] In formula (IV), A1 and A2 independently represent the divalent organic groups as shown in the following structures: .

[0075] The aforementioned A1 and A2 may further have substituents, such as alkyl groups having 1 to 6 carbon atoms.

[0076] In some embodiments, A1 and A2 are preferably selected from the divalent organic groups shown in the following structures, and A1 and A2 do not have the same structure. . In the structure shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, methyl, hydroxyl, or methoxy group. When A1 and A2 are selected from the above structures, the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has higher high and low temperature shock contrast.

[0077] In formula (IV), Y11 and Y11' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y12 and Y12' independently represent -O-, -S-, -OCO- or -COO-; Y13 and Y13' independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Y11, Y11', Y13 and Y13' are not all single bonds at the same time.

[0078] The aforementioned chain hydrocarbon groups refer to straight-chain or branched hydrocarbon groups that do not contain cyclic structures in the main chain, but are composed only of chain structures. They can be saturated or unsaturated.

[0079] In some specific examples, the chain hydrocarbon group having 1 to 10 carbon atoms may include both saturated and unsaturated chain hydrocarbon groups. The saturated chain hydrocarbon group may be a saturated straight-chain or branched chain hydrocarbon group. Examples of saturated straight-chain hydrocarbon groups include methylene, ethyl, propylene, butadiyl, pentyl, hexadiyl, heptadiyl, octyl, nonadiyl, or decadiyl. Examples of saturated branched hydrocarbon groups include dibutanediyl, debutanediyl, isopentanediyl, depentanediyl, isooctanediyl, 2-ethylhexanediyl, deoctanediyl, isononanediyl, or isodecanedanediyl. The unsaturated chain hydrocarbon group may include an unsaturated chain hydrocarbon group having unsaturated bonds (such as alkene bonds and / or alkyne bonds), and these groups may also be straight-chain or branched. For example, unsaturated chain hydrocarbon groups may be, for instance, ethylenediyl, heptenidyl, 2-butenidyl, 3-methyl-4-ethyl-1-hexenidyl, propynidyl, 2-hexynidyl, 3-methyl-1-pentynidyl, or 3-ethyl-1-hepynidyl.

[0080] Preferably, Y13 and Y13' each independently represent a single bond, and Y11 and Y11' cannot both be single bonds simultaneously. When Y13 and Y13' represent single bonds, the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has higher high and low temperature shock contrast.

[0081] In equation (IV), Z1 represents the structure shown in equation (Z1-1): (Z1-1). In formula (Z1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms.

[0082] Z1 represents R1 in formula (Z1-1), which represents an alkyl group having 1 to 6 carbon atoms. It can be linear or branched. Specifically, alkyl groups having 1 to 6 carbon atoms can include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, etc.

[0083] In formula (IV), Z 1 represents R 1 in formula (Z1-1), which represents an alkoxy group with 1 to 6 carbon atoms. These alkoxy groups can be listed as alkyl groups with 1 to 6 carbon atoms that are combined with an oxygen atom. Specifically, methoxy, ethoxy, etc. can be listed.

[0084] In formula (IV), Z 1 represents R 1 in formula (Z1-1), which represents a fluoroalkyl group having 1 to 6 carbon atoms, which can be obtained by replacing at least one hydrogen atom of the group having 1 to 6 carbon atoms with a fluorine atom.

[0085] In some embodiments, Z1 preferably represents the structure shown in equation (Z1-1-1): (Z1-1-1). In formula (Z1-1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

[0086] When Z1 in formula (IV) represents the structure shown in formula (Z1-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has a higher high and low temperature shock contrast.

[0087] In some embodiments, the diamine compound (b1-1) may comprise, but is not limited to, compounds represented by formulas (IV-1) to (IV-11): (IV-1) (IV-2) (IV-3) (IV-4) (IV-5) (IV-6) (IV-7) (IV-8) (IV-9) (IV-10) (IV-11).

[0088] The main synthetic method of the diamine compound (b1-1) is described in detail below. The method described below is only for illustrative purposes and the present invention is not limited thereto.

[0089] As shown in the following reaction formula (a), the diamine compound (b1-1) of the present invention is prepared by reducing a dinitro compound to convert the nitro group into an amino group. The reaction formula describes the diamine compound (IV-1) in the example, which is only for illustration. Reaction formula (A).

[0090] There are no particular limitations on the reduction methods for dinitro compounds. For example, palladium-carbon, platinum oxide, Raney nickel, platinum black, rhodium-alumina, and platinum sulfided on carbon (PtS / C catalysts) can be used as catalysts in solvents such as ethyl acetate, toluene, tetrahydrofuran, dioxane, and alcohols, with reduction carried out using hydrogen, hydrazine, and hydrogen chloride. Alternatively, an autoclave can be used to carry out the reduction reaction under pressure, if necessary. On the other hand, when the substituents of the hydrogen atoms in the substituted benzene ring or saturated hydrocarbon group contain unsaturated bonds, the unsaturated bonds may be reduced to saturated bonds when using palladium-carbon or platinum-carbon. Therefore, reduction conditions using transition metals such as reducing iron, tin, or tin chloride as catalysts are preferred.

[0091] The reaction temperature of reaction formula (A) can be set appropriately according to the reaction method, preferably from -20℃ to 200℃, and more preferably from 0℃ to 150℃.

[0092] In the synthesis of dinitro compounds, as shown in reaction formulas (B) and (C) below, a nitro compound containing a leaving group (X) can be obtained by reacting a commercially available nitrohydroxy aromatic derivative, nitrohydroxypyridine derivative, nitrohydroxypyrimidine derivative, or nitrohydroxydiphenyl ether derivative with a cyclohexane derivative substituted with a leaving group (X). The nitro compound containing the leaving group (X) is then reacted with another nitrohydroxy aromatic derivative, nitrohydroxypyridine derivative, nitrohydroxypyrimidine derivative, or nitrohydroxydiphenyl ether derivative to obtain the dinitro compound. Preferred leaving groups (X) include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, toluenesulfonates, and methanesulfonates. Reaction formula (B). Reaction formula (C).

[0093] The actions of reactions (B) and (C) are not particularly limited and can be carried out in the presence of a base. Furthermore, the base used is not particularly restricted as long as the target product can be synthesized; examples include inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, and sodium hydride; and organic bases such as pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and tributylamine. Depending on the circumstances, the yield can be increased when using palladium or copper catalysts in combination. Specific examples of palladium catalysts include, but are not limited to, Bis(dibenzylideneacetone)palladium, Tris(dibenzylideneacetone)dipalladium, and 1,1'-Bis(diphenylphosphino)ferrocene[dichloropalladium(II)]. The solvents used in the above reactions can be polar aprotic solvents, such as acetonitrile, dimethylformamide (DMF), acetone, and dimethylacetamide (DMAc). From the viewpoint of ease of synthesis, potassium carbonate is preferred as the base.

[0094] The reaction temperatures of reactions (B) and (C) are set appropriately according to the reaction method, preferably from -20°C to 250°C, and more preferably from 0°C to 200°C.

[0095] Based on the total amount of diamine component (b1) used being 100 mol, the amount of diamine compound (b1-1) as shown in formula (IV) used can be from 1 mol to 70 mol, preferably from 3 mol to 60 mol, and even more preferably from 5 mol to 50 mol.

[0096] If the diamine component (b1) does not contain the diamine compound (b1-1) shown in formula (IV), the liquid crystal display element formed by the liquid crystal alignment film containing this liquid crystal alignment agent is prone to problems such as low contrast due to high and low temperature shocks, resulting in poor display quality.

[0097] Diamine compound (b1-2)

[0098] The diamine component (b1) of this invention may comprise a diamine compound (b1-2), and the diamine compound (b1-2) is a diamine compound represented by formulas (A22-1) to (A22-2). (A22-1) (A22-2).

[0099] In formula (A22-1), Y 31 represents a divalent organic group as shown in formula (A22-3), and each of the plurality of Y 32 independently represents an alkyl group having 1 to 6 carbon atoms. In formula (A22-2), each of the plurality of Y 33 independently represents a divalent organic group as shown in formula (A22-3'). (A22-3) (A22-3').

[0100] In the divalent organic groups shown in formula (A22-3), Ar independently represents a divalent benzene ring, biphenyl structure, or naphthalene ring, and the hydrogen atoms of the benzene ring, biphenyl structure, or naphthalene ring can be substituted by a monovalent substituent or remain unsubstituted; Y 31' represents -(CH 2) n-, n represents an integer from 2 to 18, and at least one of the -CH 2- in -(CH 2) n- can be substituted by -O-, -C(=O)-, or -OC(=O)- or remain unsubstituted; p1 represents 0 or 1; "*" represents the bond position.

[0101] In the divalent organic groups shown in formula (A22-3'), Ar' independently represents a divalent benzene ring or biphenyl structure, and the hydrogen atoms of the benzene ring or biphenyl structure can be substituted by a monovalent substituent or remain unsubstituted; Y33' represents -(CH2)n-, where n represents an integer from 2 to 18, and at least one -CH2- in -(CH2)n- can be substituted by -O-, -C(=O)- or -OC(=O)- or remain unsubstituted; p2 represents 0 or 1; "*" represents the bond position.

[0102] In the divalent organic groups shown in formula (A22-3) and (A22-3'), the monovalent substituents of the benzene ring, biphenyl structure, or naphthyl ring are, for example, halogens, alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, fluoroalkyl groups having 1 to 10 carbon atoms, fluoroalkenyl groups having 2 to 10 carbon atoms, fluoroalkoxy groups having 1 to 10 carbon atoms, carboxyl groups, hydroxyl groups, alkoxycarbonyl groups having 1 to 10 carbon atoms, cyano groups, or nitro groups, etc.

[0103] From the viewpoint of improving liquid crystal alignment, preferably, the divalent organic group shown in formula (A22-3) is at least one of the groups shown in formulas (A22-3-1) to (A22-3-16), wherein "*" represents the bonding position. (A22-3-1) (A22-3-2) (A22-3-3) (A22-3-4) (A22-3-5) (A22-3-6) (A22-3-7) (A22-3-8) (A22-3-9) (A22-3-10) (A22-3-11) (A22-3-12) (A22-3-13) (A22-3-14) (A22-3-15) (A22-3-16).

[0104] In equation (A22-3-1), m is 0 to 1, and n is 1 to 6. In equation (A22-3-2), n is 1 to 6. In equation (A22-3-3), n is 2 to 6. In equation (A22-3-4), n is 1 to 6. In equation (A22-3-5), n is 1 to 6. In equation (A22-3-6), n is 2 to 6. In equation (A22-3-7), n is 1 to 6. In equation (A22-3-8), n is 1 to 6. In equation (A22-3-9), n is 2 to 6. In equation (A22-3-10), m is 1 to 3, and n is 1 to 4. In equation (A22-3-11), n ​​is 1 to 6. In equation (A22-3-12), n is 1 to 6. In equation (A22-3-13), m is 0 to 1, and n is 1 to 6. In equation (A22-3-14), m is 1 to 3, and n is 1 to 4.

[0105] From the viewpoint of improving the alignment of liquid crystals, it is preferable that the divalent organic group represented by formula (A22-3') is the group represented by formula (A22-3-7) to formula (A22-3-16).

[0106] When the diamine compound (b1-2) comprises a plurality of diamine compounds represented by formula (A22-1), preferably, Y 31 in formula (A22-1) represents a combination of diamine compounds of formulas (A22-3-1) to (A22-3-14) and Y 31 in formula (A22-1) represents a combination of diamine compounds of formulas (A22-3-15) to (A22-3-16).

[0107] In some embodiments of the present invention, the diamine compound represented by formula (A22-2) is, for example, but not limited to, the diamine compounds represented by formulas (A22-2-1) to (A22-2-5). (A22-2-1) (A22-2-2) (A22-2-3) (A22-2-4) (A22-2-5).

[0108] In equation (A22-2-1), m is 1 to 6, and n is 1 to 6. In equation (A22-2-2), m is 1 to 6, and n is 1 to 6. In equation (A22-2-3), m is 2 to 6, and n is 2 to 6.

[0109] The diamine compound (b1-1) can be used alone or in combination with other compounds. In some embodiments of the invention, based on a total amount of 100 mol of diamine component (b1), the amount of diamine compound (b1-2) used is 30 to 99 mol, preferably 40 to 97 mol, and more preferably 50 to 95 mol.

[0110] Diamine compounds (b1-3)

[0111] In some embodiments of the present invention, the diamine component (b1) further comprises diamine compounds (b1-3) having a -N(D)- group.

[0112] From the viewpoint of improving the voltage retention rate of liquid crystal display elements, the molecular structure of the first polymer (A1) may selectively have a -N(D)- group (where D represents a carbamate protecting group). The first polymer (A1) having the -N(D)- group can be obtained by using a monomer having the -N(D)- group as at least a portion of the reactants, or by using a monomer having the -N(D)- group as a capping agent as described below. In some specific examples, the monomer having the -N(D)- group is, for example, a diamine compound (b1-3) having the -N(D)- group. For example, the carbamate protecting group is, for example, but not limited to, terbutoxycarbonyl (Boc) or 9-pyromethoxycarbonyl.

[0113] Preferably, the diamine compound (b1-3) having the -N(D)- group comprises a diamine compound having at least one aromatic group (e.g., a benzene ring). More preferably, the diamine compound (b1-3) having the -N(D)- group comprises a diamine compound having at least one aromatic group and having residues other than the substituent (D) having 6 to 30 carbon atoms. In some specific examples, the diamine compound (b1-3) having the -N(D)- group is, for example, but not limited to, the diamine compounds shown in formulas (A23-1) to (A23-11). (A23-1) (A23-2) (A23-3) (A23-4) (A23-5) (A23-6) (A23-7) (A23-8) (A23-9) (A23-10) (A23-11).

[0114] In equation (A23-1), n ​​is 1 to 6. In equation (A23-2), n is 1 to 6. In equation (A23-4), m is 1 to 6, and n is 1 to 6. In equation (A23-7), m is 1 to 6, and n is 1 to 6. In equation (A23-9), n is 1 to 6. In equation (A23-11), n ​​is 1 to 6.

[0115] The diamine compound (b1-3) having the -N(D)- group can be used alone or in combination. Based on a total amount of 100 mol of diamine component (b1), the amount of diamine compound (b1-3) used can be from 10 mol to 99 mol, preferably from 12 mol to 97 mol, and even more preferably from 15 mol to 95 mol.

[0116] Other diamine compounds (b1-4)

[0117] In some embodiments of the present invention, the diamine component (b1) also includes other diamine compounds (b1-4).

[0118] Other diamine compounds (b1-3) include, but are not limited to, diamine compounds having photoalignment groups, 4-amino-N-methylphenethylamine, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, diamine compounds having carboxyl groups, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane Diamine diphenyl ketone, 1,4-bis(4-aminobenzyl)benzene, 4,4'-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, diamine compounds with urea bonds, diamine compounds with amide bonds, diamine compounds with photopolymerizable groups at the ends, diamine compounds with siloxane bonds, or diamine compounds with acezoline structures, etc.

[0119] The aforementioned diamine compounds having photoalignment groups include, but are not limited to, 4,4'-diaminoazobenzene, or diamine compounds represented by formulas (A24-1) to (A24-3), etc. (A24-1) (A24-2) (A24-3).

[0120] The aforementioned diamine compounds having a carboxyl group include, but are not limited to, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds of formulas (A24-4) to (A24-7), etc. (A24-4) (A24-5) (A24-6) (A24-7).

[0121] In formula (A24-4), Y 51 represents a single bond, -CH 2-, -C 2H 4-, -C(CH 3) 2-, -CF 2-, -C(CF 3) 2-, -O-, -CO-, -NH-, -N(CH 3)-, -CONH-, -NHCO-, -CH 2O-, -OCH 2-, -COO-, -OCO-, -CON(CH 3)-, or -N(CH 3)CO-; m1 and m2 each independently represent integers from 0 to 4, and (m1+m2) represents integers from 1 to 4. In formula (A24-5), m3 and m4 each independently represent integers from 1 to 5. In formula (A24-6), Y 52 represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms; m5 represents integers from 1 to 5. In equation (A24-7), Y53 and Y54 independently represent single bonds, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-; m6 represents an integer from 1 to 4.

[0122] The aforementioned diamine compounds containing urea bonds include, but are not limited to, the diamine compounds shown in formulas (A24-8) to (A24-10). (A24-8) (A24-9) (A24-10).

[0123] In equation (A24-8), n1 is 0 to 6, and n2 is 1 to 6. In equation (A24-9), n1 is 1 to 6, and n2 is 1 to 6. In equation (A24-10), n is 1 to 6.

[0124] The aforementioned diamine compounds having amide bonds are, for example, but not limited to, the diamine compounds having amide bonds shown in formulas (A24-11) to (A24-13). (A24-11) (A24-12) (A24-13).

[0125] In equation (A24-12), n is 1 to 6. In equation (A24-13), n1 is 1 to 6, and n2 is 1 to 6.

[0126] The aforementioned diamine compounds with photopolymerizable groups at the ends include, but are not limited to, 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline.

[0127] The diamine compounds with siloxane bonds mentioned above include, but are not limited to, 3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0128] The aforementioned diamine compounds having an acezoline structure include, but are not limited to, the diamine compounds shown in formulas (A24-14) to (A24-15), etc. (A24-14) (A24-15).

[0129] The aforementioned other diamine compounds (b1-4) may be used alone or in combination. In some embodiments of the present invention, based on a total amount of 100 mol of diamine component (b1), the amount of other diamine compounds (b1-4) may be from 10 mol to 99 mol, preferably from 12 mol to 97 mol, and more preferably from 15 mol to 95 mol.

[0130] Second polymer (A2)

[0131] In some embodiments of the present invention, polymer component (A) further includes a second polymer (A2).

[0132] The second polymer (A2) is selected from at least one of the group consisting of a polyimide precursor formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (a2) and a diamine component (b2) and a amide polymer formed from the polyimide precursor, and the second polymer (A2) does not contain the structure shown in formula (I) of the first polymer (A1). For example, the second polymer (A2) is a polyimide precursor having a polyamide and polyamide ester amide precursor structure, or the second polymer (A2) is an amide polymer (i.e., polyimide) formed from the polyimide precursor, or the second polymer (A2) comprises the polyimide precursor and the amide polymer, etc. The second polymer (A2) can be used alone or in combination with several others.

[0133] In some embodiments, the weight ratio of the first polymer (A1) to the second polymer (A2) [i.e., the mass ratio of the first polymer (A1) to the second polymer (A2)] is 10 / 90 to 90 / 10, preferably 20 / 80 to 90 / 10, and more preferably 20 / 80 to 80 / 20.

[0134] When polymer component (A) includes a second polymer (A2), the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has a higher high and low temperature shock contrast.

[0135] Tetracarboxylic dianhydride component (a2)

[0136] The tetracarboxylic dianhydride component (a2) is, for example, but not limited to, acyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, aromatic tetracarboxylic dianhydride compounds, or derivatives of these compounds. The acyclic aliphatic tetracarboxylic dianhydride compound, the alicyclic tetracarboxylic dianhydride compound, and the aromatic tetracarboxylic dianhydride compound are, for example, tetracarboxylic dianhydride compounds in the first polymer (A1). Preferably, the tetracarboxylic dianhydride component (a2) comprises an alicyclic tetracarboxylic dianhydride or a derivative thereof as shown in formula (A11), or a tetracarboxylic dianhydride compound or a derivative thereof as shown in formula (A12) above, where X 1' represents the structure shown in formulas (A12-1) to (A12-6). The tetracarboxylic dianhydride component (a2) may be used alone or in combination of multiple components.

[0137] Preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound (a2-1) with the structure shown in formula (A12) and X1' having the structure shown in formula (III). (III).

[0138] In equation (III), Z 11 represents a single bond, and "*" represents the bond position.

[0139] The aforementioned tetracarboxylic acid dianhydride compound (a2-1) can be used alone or in combination of multiple compounds.

[0140] More preferably, the tetracarboxylic dianhydride component (a2) comprises a tetracarboxylic dianhydride compound as shown in formula (IV): (IV).

[0141] In some embodiments of the present invention, based on the total amount of the tetracarboxylic acid dianhydride component (a2) being 100 mol, the amount of the tetracarboxylic acid dianhydride compound (a2-1) used is 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0142] Diamine component (b2)

[0143] The diamine component (b2) may be, for example, but not limited to, the diamine component (b1) of the first polymer (A1), or a diamine compound (b2-1) having a nitrogen-containing structure, but the diamine component (b2) does not contain a diamine compound (b1-1) having the structure shown in formula (IV). The diamine component (b2) may be used alone or in combination of multiple types.

[0144] Diamine compound (b2-1)

[0145] The nitrogen-containing structure of the diamine compound (b2-1) having a nitrogen-containing structure is selected from at least one of the group consisting of nitrogen-containing heterocycles, secondary amine groups and tertiary amine groups.

[0146] The nitrogen-containing heterocycle of the diamine compound (b2-1) having a nitrogen-containing atom structure includes, but is not limited to, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridine, indole, benzimidazole, purine, quinoline, isoquinoline, acetidine, quinoline, pyridine, triazole, carbazole, acridine, piperidine, piperidine, pyrrolidine, or hexamethyleneimine, etc. Preferably, the nitrogen-containing heterocycle is pyridine, pyrimidine, pyridine, piperidine, piperidine, quinoline, carbazole, or acridine.

[0147] The nitrogen-containing structure of the diamine compound (b2-1) with nitrogen-containing atom structure described above is a secondary amine group and a tertiary amine group as shown in formula (B21). (B21).

[0148] In formula (B21), Z represents a hydrogen atom or an alkyl, cycloalkyl, or aryl group having 1 to 10 carbon atoms; "*" represents a bond position.

[0149] The alkyl group having 1 to 10 carbon atoms is, for example, but not limited to, methyl, ethyl, or propyl; the cycloalkyl group is, for example, but not limited to, cyclohexyl; the aryl group is, for example, but not limited to, phenyl or tolyl. Z is preferably a hydrogen atom or a methyl group.

[0150] The aforementioned diamine compounds having a nitrogen-containing structure (b2-1) include, but are not limited to: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamine compounds of formulas (B21-1) to (B21-8), or diamine compounds of formulas (B21-9) to (B21-26). (B21-1) (B21-2) (B21-3) (B21-4) (B21-5) (B21-6) (B21-7) (B21-8) (B21-9) (B21-10) (B21-11) (B21-12) (B21-13) (B21-14) (B21-15) (B21-16) (B21-17) (B21-18) (B21-19) (B21-20) (B21-21) (B21-22) (B21-23) (B21-24) (B21-25) (B21-26).

[0151] In formula (B21-5), n represents 1 to 4. In formula (B21-6), n represents 1 to 4. The diamine compound (b2-1) having a nitrogen-containing structure can be used alone or in combination.

[0152] When the diamine component (b2) contains the above-mentioned diamine compound (b2-1) having a nitrogen-containing atom structure, the liquid crystal display element formed by the liquid crystal alignment film containing this liquid crystal alignment agent has a higher high and low temperature shock contrast.

[0153] In some embodiments of the present invention, the total amount of the diamine component (b2) used is 100 mol, and the amount of the diamine compound (b2-1) having a nitrogen-containing atom structure used is from 15 mol to 100 mol, preferably from 20 mol to 90 mol, and more preferably from 25 mol to 80 mol.

[0154] Preparation methods of the first polymer (A1) and the second polymer (A2)

[0155] The first polymer (A1) and the second polymer (A2) can be manufactured by performing a (condensation polymerization) reaction between the aforementioned diamine component and tetracarboxylic dianhydride component in a solvent. When a portion of the first polymer (A1) and the second polymer (A2) has an acetic acid structure, for example, by reacting the tetracarboxylic dianhydride component with the diamine component, a polymer with an acetic acid structure (i.e., polyacetic acid) can be obtained. The aforementioned solvent is not particularly limited, as long as it can dissolve the formed polymer. For example, solvents 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-imidazolidinedione. In some embodiments of the present invention, when the polymer has high solvent solubility, the solvent is, for example, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents as shown in formulas (D-1) to (D-3). (D-1) (D-2) (D-3)

[0156] In formula (D-1), Z1 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-2), Z2 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-3), Z3 represents an alkyl group having 1 to 4 carbon atoms.

[0157] The aforementioned solvents can be used alone or in combination. Furthermore, even solvents that cannot dissolve the polymer can be mixed with the aforementioned solvents within a range that will not cause the resulting polymer to precipitate. When the diamine component and the tetracarboxylic dianhydride component react in the solvent, the reaction can proceed at any concentration; preferably, the concentration is 1 wt% to 50 wt%, more preferably 5 wt% to 30 wt%. The reaction can also be initially carried out at a high concentration, followed by the addition of additional solvent. During the reaction, preferably, the ratio of the total moles of the diamine component to the total moles of the tetracarboxylic dianhydride component is 0.8 to 1.2. Similar to general polycondensation reactions, the closer the ratio of the total moles of the diamine component to the total moles of the tetracarboxylic dianhydride component is to 1.0, the larger the molecular weight of the first polymer (A1) or the second polymer (A2) formed.

[0158] Polymers having a polyamide ester structure can be obtained, for example, by conventional methods, which are (1) reacting the polyamide obtained by the above methods with an esterifying agent, (2) reacting a tetracarboxylic acid diester compound with a diamine compound, or (3) reacting a tetracarboxylic acid diester dihalide with a diamine compound.

[0159] The amide polymer in the first polymer (A1) or second polymer (A2) of the liquid crystal alignment agent of the present invention can be obtained, for example, by cyclizing the polymer having an amide ester structure. In the amide polymer, the cyclization rate (also called the amide ratio) of the functional groups of the amide group or its derivatives is not necessarily 100%, and the amide ratio of the amide polymer can be arbitrarily adjusted according to the application and / or purpose.

[0160] Methods for obtaining amide-imidized polymers include, for example, thermal amide imidization by directly heating a solution containing a polymer having an amide ester structure, or catalytic amide imidization by adding a catalyst to the solution. When thermal amide imidization is carried out in the solution, the temperature is preferably between 100°C and 400°C, more preferably between 120°C and 250°C. During thermal amide imidization, it is preferable to simultaneously remove water generated during the amide imidization reaction from the system.

[0161] The aforementioned catalytic acetylation is carried out, for example, by adding an alkaline catalyst and an acid anhydride to the solution. Preferably, the reaction is carried out at a temperature of -20°C to 250°C, more preferably at a temperature of 0°C to 180°C. Preferably, the amount of alkaline catalyst added is 0.5 to 30 times the molar equivalent of the acetic acid group, more preferably 2 to 20 times. Preferably, the amount of acid anhydride added is 1 to 50 times the molar equivalent of the acetic acid group, more preferably 3 to 30 times. The alkaline catalyst is, for example, but not limited to, pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine. Among these, pyridine is preferred because it has a moderate alkalinity that allows the reaction to proceed. The acid anhydride is, for example, but not limited to, acetic anhydride, trimellitic anhydride, or phenylmethyltetrahydroquinone. Among these, the use of acetic anhydride makes purification after the reaction easier, which is preferred. The amide rate of catalytic amide can be controlled by adjusting the amount of catalyst, reaction temperature, and / or reaction time.

[0162] When recovering the amided polymer from the amided reaction solution described above, the reaction solution is added to a solvent and allowed to precipitate. Solvents used for precipitation include, but are 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 in the solvent, it can be dried at room temperature or under normal or reduced pressure. Alternatively, the recovered polymer can be dissolved in a solvent and reprecipitated; this process can be repeated 2 to 10 times to reduce impurities in the polymer. Solvents used can be, for example, alcohols or ketone hydrocarbons. Using three or more of the selected solvents can further improve the purification efficiency, making it ideal.

[0163] The solution viscosity and molecular weight of polymers

[0164] When prepared into solutions with a concentration of 10 wt% to 15 wt%, the solution viscosity of the first polymer (A1) or the second polymer (A2) of the present invention is not particularly limited. From the viewpoint of ease of operation, its solution viscosity can be, for example, from 10 mPa·s to 1000 mPa·s. The solution viscosity (mPa·s) of the polymer is the value measured at 25°C using a rotational viscometer at a concentration of 10 wt% to 15 wt% prepared using a good solvent for the polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone).

[0165] Preferably, the weight-average molecular weight (Mw) of the first polymer (A1) or the second polymer (A2) of the present invention, as measured by gel permeation chromatography (GPC) based on polystyrene, is between 1,000 and 500,000, more preferably between 2,000 and 500,000. Secondly, more preferably, the molecular weight distribution (Mw / Mn) expressed by the ratio of Mw to the number-average molecular weight (Mn) of polystyrene measured by GPC is 15 or less, more preferably 10 or less. When the molecular weight of the polymer is within the above-mentioned range, good alignment and stability of the liquid crystal display element can be ensured.

[0166] End capping agent

[0167] When synthesizing the first polymer (A1) or the second polymer (A2) of the present invention, the tetracarboxylic acid dianhydride component and the diamine component as described above can be used, and an end-sealing polymer can be synthesized using a suitable end-sealing agent. The end-sealing polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating, and improving the adhesion properties of the sealant and the liquid crystal alignment film. The ends of the first polymer (A1) or the second polymer (A2) of the present invention can be, for example, amino groups, carboxyl groups, anhydride groups, or derivatives thereof. Amino groups, carboxyl groups, anhydride groups, or derivatives thereof can be obtained by a general condensation reaction, or by sealing the ends using the end-sealing agent described below. Similarly, the above-mentioned derivatives can be obtained, for example, using the end-sealing agent described below.

[0168] The capping agents are, for example, but not limited to, acid anhydrides, dicarbonate ester compounds, chlorocarbonyl compounds, monoamine compounds, or monoisocyanate compounds. The aforementioned acid anhydrides are, for example, but not limited to, acetic anhydride, maleic anhydride, nalidixic 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. The aforementioned dicarbonate ester compounds are, for example, but not limited to, ditert-butyl dicarbonate or diallyl dicarbonate. The aforementioned chlorocarbonyl compounds are, for example, but not limited to, acrylonitrile chloride, methacrylonitrile chloride, or nicotinic acid chloride. The aforementioned monoamine compounds include, but are not limited to, 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. The aforementioned monoisocyanate compounds include, but are not limited to, ethyl isocyanate, phenyl isocyanate, or naphthyl isocyanate.

[0169] The capping agent can be used alone or in combination with several others. In some embodiments of the invention, preferably, based on a total amount of 100 moles of diamine components, the amount of capping agent used is 0.01 to 20 moles, and more preferably 0.01 to 10 moles.

[0170] Other polymers

[0171] The polymer component (A) of the liquid crystal alignment agent of the present invention may optionally also include other polymers. These other polymers are, for example, but not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or derivatives thereof, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates, etc.

[0172] Solvent (B)

[0173] From the viewpoint of forming a uniform thin film, the liquid crystal alignment agent is taken in the form of a coating solution to produce a liquid crystal alignment film. Preferably, the liquid crystal alignment agent of the present invention is a coating solution containing a polymer component (A) and a solvent (B). The concentration of the polymer component (A) in the liquid crystal alignment agent can be appropriately varied based on the desired coating thickness. From the viewpoint of forming a uniform and defect-free coating film, the concentration of the polymer component (A) in the liquid crystal alignment agent is preferably 1 wt% or more. From the viewpoint of the storage stability of the solution, the concentration of the polymer component (A) in the liquid crystal alignment agent is preferably 10 wt% or less. Ideally, the concentration of the polymer component (A) is 2 wt% to 8 wt%. The content of the polymer component (A) in the liquid crystal alignment agent can be appropriately varied by the coating method of the liquid crystal alignment agent and / or the desired film thickness of the liquid crystal alignment film, preferably 2 wt% to 10 wt%, more preferably 3 wt% to 8 wt%.

[0174] The solvent (B) in the liquid crystal alignment agent is, for example, an organic solvent, and there are no particular limitations on the solvent (B), as long as it can uniformly dissolve the polymer component (A). The solvent (B) includes, but is not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidineone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionic acid, and 3-butoxy-N,N-dimethylpropionic acid. Solvents such as 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 are preferred. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, or γ-butyrolactone are preferred. In some embodiments of the present invention, the total amount of solvent (B) in the liquid crystal alignment agent is 100 wt%, and the amount of good solvent used is 20 wt% to 99 wt%, preferably 20 wt% to 90 wt%, and more preferably 30 wt% to 80 wt%.

[0175] Secondly, preferably, the solvent (B) in the liquid crystal alignment agent includes the aforementioned good solvent, as well as a lean solvent that can improve the coatability and surface smoothness of the coating film during liquid crystal alignment agent coating. Preferably, based on the total amount of solvent (B) in the liquid crystal alignment agent being 100 wt%, the amount of the lean solvent used is 1 wt% to 80 wt%, more preferably 10 wt% to 80 wt%, and even more preferably 20 wt% to 70 wt%. The type and amount of the lean solvent can be appropriately selected according to the coating apparatus, coating conditions, and / or coating environment of the liquid crystal alignment agent.

[0176] The lean solvents mentioned include, but are not limited to, diisopropyl ether, diisobutyl ether, diisobutylmethanol (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, propenyl carbonate, propenyl carbonate, ethylene glycol monobutyl ether (butyl ceroxox), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, and 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, isoamyl lactate, diethylene glycol monoethyl ether, or diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0177] Preferably, the lean solvent is diisobutylmethanol, 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, etc.

[0178] Preferably, solvent combinations of good and poor solvents include, but are 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-dimethyllactamine 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-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-ethyl ... Diol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyllactamine and ethylene glycol monobutyl ether; N,N-dimethyllactamine and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyllactamine 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 monobutyl ether Diol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylmethanol; 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-dimethyllactamine and diisobutyl ketone, etc.

[0179] The aforementioned solvent (B) can be used alone or in combination with other solvents. In some embodiments of the present invention, based on a total amount of 100 parts by weight of polymer component (A), the amount of solvent (B) used is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

[0180] Additive ingredients

[0181] The liquid crystal alignment agent of the present invention also includes additives. These additives include, but are not limited to, adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate or the liquid crystal alignment film and the sealant, crosslinking compounds for improving the strength of the liquid crystal alignment film, compounds for promoting amide imidization, and dielectrics or conductive materials for adjusting the dielectric constant or resistance of the liquid crystal alignment film.

[0182] Sealing agent

[0183] The aforementioned sealing aids include, but are not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethyleneethyltriamine, N-trimethoxysilylpropyltriethyleneethyltriamine, and vinyltrimethylsilyl... Silane coupling agents including oxysilanes, vinyltriethoxysilanes, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilanes, 3-epoxypropoxypropylmethyldimethoxysilanes, 3-epoxypropoxypropyltrimethoxysilanes, 3-epoxypropoxypropylmethyldiethoxysilanes, 3-epoxypropoxypropyltriethoxysilanes, 3-methacryloxypropylmethyldimethoxysilanes, 3-methacryloxypropylmethyldiethoxysilanes, 3-methacryloxypropylmethyldiethoxysilanes, 3-methacryloxypropyltriethoxysilanes, 3-propenyloxypropyltrimethoxysilanes, tris(3-trimethoxysilylpropyl)isocyanurate, or 3-isocyanate propyltriethoxysilane. When using an adhesive additive, based on the viewpoint of exhibiting good resistance to AC image retention, it is preferable that the amount of adhesive additive used is 0.1 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to the total amount of polymer component (A) used in the liquid crystal alignment agent being 100 parts by weight.

[0184] Cross-linked compounds

[0185] For the aforementioned crosslinking compounds, based on the viewpoint of exhibiting good resistance to AC residue and effectively improving film strength, they can be compounds having ethylene oxide, propylene oxide, at least one group selected from the group composed of the group shown in formula (E1) and the group shown in formula (E2), or compounds selected from the compound shown in formula (E3). (E1) (E2) (E3).

[0186] In formula (E1), G1 and G2 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH2-OH. In formula (E2), G3 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. G4 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. In formula (E3), G5 represents an organic group with a (g1+g2) valence containing an aromatic ring. G6 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. g1 represents an integer from 1 to 6, and g2 represents an integer from 0 to 4.

[0187] In formula (E3), the (g1+g2) valence organic group represented by G5 can include (g1+g2) valence aromatic hydrocarbon groups with 6 to 30 carbon atoms, (g1+g2) valence organic groups formed by direct or inter-linking groups of aromatic hydrocarbon groups with 6 to 30 carbon atoms, or (g1+g2) valence groups having aromatic heterocycles. The aromatic hydrocarbon can be, for example, benzene or naphthalene. The aromatic heterocycle can be exemplified by the specific nitrogen-containing structures described above. The linking group can be an alkyl group with 1 to 10 carbon atoms or a group from which one hydrogen atom is removed, or divalent or trivalent cyclohexane, etc. Any hydrogen atom of the alkyl group can also be replaced by a fluorine atom or an organic group such as trifluoromethyl. In formula (E3), the alkyl group represented by G6 with 1 to 5 carbon atoms can be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, dibutyl, terbutyl or n-pentyl.

[0188] Compounds containing ethylene oxide

[0189] Specific examples of compounds containing ethylene oxide include N,N,N',N'-tetracyclooxypropylmethylenediamine, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetracyclooxypropyl-p-phenylenediamine, and compounds containing nitrogen atoms as shown in formulas (E4) to (E6). (E4) (E5) (E6).

[0190] Compounds containing propylene oxide

[0191] Specific examples of compounds containing propylene oxide are shown in the following formulas (E7) to (E16): (E7) (E8) (E9) (E10) (E11) (E12) (E13) (E14) (E15) (E16).

[0192] In equation (E15), R represents , where "*" represents the location of the bond.

[0193] Compounds having groups as shown in formula (E1)

[0194] Specific examples of compounds having groups as shown in formula (E1) are listed below, as shown in formulas (E1-1) to (E1-12): (E1-1) (E1-2) (E1-3) (E1-4) (E1-5) (E1-6) (E1-7) (E1-8) (E1-9) (E1-10) (E1-11) (E1-12).

[0195] Compounds having groups as shown in formula (E2)

[0196] Specific examples of compounds having groups as shown in formula (E2) are listed below, as shown in formulas (E2-1) to (E2-4): (E2-1) (E2-2) (E2-3) (E2-4).

[0197] Compounds having groups as shown in formula (E3)

[0198] Specific examples of compounds having groups as shown in formula (E3) are compounds shown in formulas (E3-1) to (E3-10): (E3-1) (E3-2) (E3-3) (E3-4) (E3-5) (E3-6) (E3-7) (E3-8) (E3-9) (E3-10).

[0199] In the liquid crystal alignment agent of the present invention, the total amount of polymer used in the liquid crystal alignment agent is 100 parts by weight, and the amount of crosslinking compound used is preferably 0.5 parts by weight to 20 parts by weight. Furthermore, based on the viewpoint of promoting the crosslinking reaction and exhibiting good resistance to AC image retention, the amount of crosslinking compound used is more preferably 1 part by weight to 15 parts by weight.

[0200] Compounds that promote acetylation

[0201] The aforementioned compounds used to promote aceimination are preferably compounds having a basic site (e.g., a primary amino 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 aforementioned crosslinking compounds and binding aids), or compounds that produce the basic site upon calcination. More preferably, the compound promoting aceimination is a compound that produces the basic site upon calcination, and specific examples may be, for example, amino acids in which part or all of the basic site is protected. Specific examples of the aforementioned amino acids include glycine, alanine, cysteine, methionine, aspartic acid, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. For the purpose of promoting aceimination, a better specific example is N-α-(9-enylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0202] Fabrication method of liquid crystal alignment film and liquid crystal display element

[0203] 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 horizontally aligned or vertically aligned (VA type) liquid crystal alignment film, and it is suitable for horizontally aligned liquid crystal display elements such as IPS or FFS types. The liquid crystal display element of the present invention includes the aforementioned liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by the following steps (1) to (4) or steps (1) to (2) and (4).

[0204] Step (1): Apply liquid crystal alignment agent to the substrate.

[0205] The liquid crystal alignment agent of this invention is coated onto one side of a substrate having a patterned transparent conductive film using a suitable coating method such as roll coating, spin coating, printing, or inkjet printing. The substrate is not particularly limited; it only needs to be a highly transparent substrate. Glass substrates or silicon nitride substrates can be used in combination with plastic substrates such as acrylic substrates or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if only a single-sided substrate is used, opaque materials such as silicon wafers can be used, and the electrodes can be made of light-reflective materials such as aluminum. Moreover, when manufacturing IPS or FFS type liquid crystal elements, the comb-type uses an electrode substrate composed of a patterned transparent conductive film or metal film and an opposing substrate without electrodes.

[0206] Methods for coating liquid crystal alignment agents onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray coating. Among these, inkjet coating is considered the best method for film formation.

[0207] Step (2): Calcination of the coated liquid crystal alignment agent

[0208] Step (2) is the step of calcining the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated by heating means such as a hot plate, a thermal cycling oven, or an IR (infrared) oven, or the polyamide or polyamide ester can be thermally amided. The drying and calcination steps performed after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and multiple drying or calcination steps can be performed. The drying temperature can be, for example, 40°C to 180°C. From the viewpoint of shortening the processing time, it can be performed at 40°C to 150°C. The drying time is not particularly limited, and can be, for example, 1 minute to 10 minutes or 1 minute to 5 minutes. When performing thermal amide of polyamide or polyamide ester, 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. There is no particular limitation on the calcination time, which can be listed as 5 to 40 minutes or 5 to 30 minutes. If the calcined film is too thin, the reliability of the liquid crystal display element will be reduced. Therefore, the film thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm.

[0209] Step (3): Perform alignment treatment on the membrane obtained in step (2).

[0210] Step (3) involves performing alignment treatment on the film obtained in step (2), depending on the circumstances. In other words, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to alignment treatment to impart alignment capability. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA, the formed coating can be used directly as a liquid crystal alignment film, but it can also be subjected to alignment treatment to impart alignment capability. Alignment treatment of liquid crystal alignment films can include rubbing treatment or photoalignment treatment, with photoalignment treatment being preferred. Photoalignment treatment can include irradiating the surface of the film with radiation that has been deflected in a certain direction, and, depending on the circumstances, heating it at a temperature of 150°C to 250°C to impart liquid crystal alignment properties (also known as liquid crystal alignment capability). The radiation can be ultraviolet light or visible light with a wavelength of 100 nm to 800 nm. The radiation is preferably ultraviolet light with a wavelength of 100 nm to 400 nm, and more preferably ultraviolet light with a wavelength of 200 nm to 400 nm.

[0211] The aforementioned radiation exposure can be from 1 mJ / cm² to 10,000 mJ / cm², more preferably from 100 mJ / cm² to 5,000 mJ / cm², even more preferably from 100 mJ / cm² to 1500 mJ / cm², and even more preferably from 100 mJ / cm² to 1000 mJ / cm². When using a conventional liquid crystal alignment agent, the light exposure for alignment treatment is from 100 mJ / cm² to 5000 mJ / cm². However, the liquid crystal alignment agent of this invention, even with a reduced light exposure for alignment treatment, can still produce a liquid crystal alignment film where variations (non-uniformity) in the liquid crystal alignment within the film surface are effectively suppressed. During radiation irradiation, to improve liquid crystal alignment, the substrate of the aforementioned film can be heated at 50°C to 250°C simultaneously with irradiation. The liquid crystal alignment film produced in this manner allows liquid crystal molecules to be stably aligned in a specific direction. Secondly, in the aforementioned method, the liquid crystal alignment film that has been irradiated with polarized radiation can be contacted with a solvent, or the liquid crystal alignment film that has been irradiated with radiation can be heated.

[0212] There are no particular limitations on the solvents used in the aforementioned contact treatment, as long as they can dissolve the decomposition products generated from the film after radiation irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl ceroxysulfate, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate, etc. Among these, based on the viewpoint of versatility and safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred, and more preferably water, 1-methoxy-2-propanol, or ethyl lactate. The solvent can be used alone or in combination.

[0213] The temperature for heat treatment of the aforementioned irradiated coating is preferably 50°C to 300°C, and more preferably 120°C to 250°C. The heat treatment time is preferably 1 minute to 30 minutes.

[0214] Step (4): Fabrication of liquid crystal cells

[0215] Prepare two liquid crystal alignment film substrates as described above, and place liquid crystal between the two substrates facing each other. For example, the following two methods can be listed. In the first method, firstly, place the two substrates facing each other with their respective liquid crystal alignment film surfaces facing each other, separated by a gap (intercellular space). Then, bond the peripheries of the two substrates together with a sealant, and then inject the liquid crystal composition to fill the intercellular space separated by the substrate surface and the sealant. After it contacts the film surface, seal the injection hole.

[0216] The second method is called ODF (One Drop Fill). A UV-curable sealant is applied to predetermined positions on one of two substrates with a pre-formed liquid crystal alignment film. Liquid crystal composition is then dropped onto multiple predetermined positions on the alignment film surface. The other substrate is then bonded with the alignment films facing each other, pressing the liquid crystal composition onto the entire surface of the substrate, bringing it into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to harden the sealant. When performing any of the aforementioned methods, it is preferable to further heat the liquid crystal composition to a temperature that achieves isotropic properties, and then slowly cool it to room temperature to remove flow alignment issues during liquid crystal filling. Furthermore, when performing a friction treatment on the coating, the two substrates are arranged facing each other at predetermined angles along the friction directions of their respective coatings, for example, orthogonal or antiparallel. The sealant can be, for example, epoxy resin containing a hardener and alumina balls as spacers. Liquid crystal components may include nematic liquid crystals and lamellar liquid crystals, with nematic liquid crystals being more preferred.

[0217] A polarizing plate can be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. The polarizing plate attached to the outer surface of the liquid crystal cell can be a polarizing film that extends and aligns with polyvinyl alcohol while simultaneously absorbing iodine, and is called an "H-film". It can be a polarizing plate sandwiched between a cellulose acetate protective film, or a polarizing plate composed of the H-film itself.

[0218] The following examples illustrate the application of the present invention, but are not intended to limit the invention. Anyone skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention.

[0219] Preparation of diamine compound (b1-1) as shown in diamine formula (IV)

[0220] Synthetic example b1-a

[0221] Synthetic Example b1-a synthesizes the compound shown in formula (IV-1) above, which can be prepared by the following method.

[0222] Step 1: Add 13.9 g (0.1 mol) of reactant A (4-nitrophenol); ) with 29.8 g (0.1 mole) of reactant B (1,4-bis(2-bromomethyl)cyclohexane); The first intermediate product ( ) was dissolved in 0.3 L of acetonitrile (ACN), and then 27.6 g (0.2 mol) of potassium carbonate was added to form a mixture. The mixture was then stirred at 77 °C for 4 hours, filtered, and the filtrate was collected and dried. Next, the mixture was stirred and mixed with 1 L of methanol at 50 °C for 1 hour, filtered, dried, and the white solid was collected. ).

[0223] Step 2: 34.2 g (0.1 mol) of the first intermediate was reacted with 21.5 g (0.1 mol) of reactant C (4-nitro-4'-hydroxybiphenyl); The product was dissolved in 1 L of ACN, and then 27.6 g (0.2 mol) of potassium carbonate was added to form a mixture. The mixture was stirred at 79 °C for 3 hours, and then filtered after the reaction. Next, the reaction product was washed at 50 °C for 1 hour with a mixed solution of 500 g water and 150 g methanol. Then, it was cooled, filtered, and vacuum dried to obtain the second intermediate product. ).

[0224] Step 3: Dissolve 49.1 g (0.1 mol) of the second intermediate in 2.5 L of a mixed solution containing THF and ethanol, and then add 4 g (10 wt%) of palladium-carbon. The mixture is then heated to 40 °C, followed by slow titration of 20.0 g (0.4 mol) of hydrazinium hydroxide. After titration, the temperature is raised to 60 °C. After stirring for 3.5 hours, the mixture is filtered, and the filtrate is collected and subjected to reduced pressure filtration and vacuum drying to obtain the diamine compound (b1-a) as shown in formula (IV-1).

[0225] Synthetic example b1-b

[0226] Synthetic Examples b1-b series synthesize compounds as shown in formula (IV-2) using the same preparation method and reactant molar ratio as compounds shown in formula (IV-1). The difference lies in the reactant B series used in compounds shown in formula (IV-2), which is 1,4-bis(2-bromoethyl)cyclohexane. Therefore, different first intermediate products are obtained. ) and the second intermediate ( Thus, a diamine compound (b1-b) as shown in formula (IV-2) can be prepared.

[0227] Synthetic example b1-c

[0228] Synthetic Examples b1-c synthesize compounds as shown in Formula (IV-3) using the same preparation method and reactant molar ratio as compounds shown in Formula (IV-2). The difference lies in the reactant A used in compounds shown in Formula (IV-3), which is 4-nitrobenzoic acid. Therefore, different first intermediate products are obtained. ) and the second intermediate ( Thus, diamine compounds (b1-c) as shown in formula (IV-3) can be prepared.

[0229] Synthetic example b1-d

[0230] Synthetic Examples b1-d synthesize compounds as shown in Formula (IV-7) using the same preparation method and reactant molar ratio as compounds as shown in Formula (IV-1). The difference lies in the reactant B used in compounds as shown in Formula (IV-7), which is 1,3-bis(bromomethyl)cyclohexane. Therefore, different first intermediate products are obtained. ) and the second intermediate product ( Thus, diamine compounds (b1-d) as shown in formula (IV-7) can be prepared.

[0231] Synthetic example b1-e

[0232] Synthetic Examples b1-e series synthesize compounds as shown in formula (IV-8) using the same preparation method and reactant molar ratio as compounds shown in formula (IV-7). The difference lies in the reactant C series used in compounds shown in formula (IV-8): 6-(4-nitrophenyl)-3-pyridinol. Therefore, a different second intermediate product is obtained. Thus, diamine compounds (b1-e) as shown in formula (IV-8) can be prepared.

[0233] Preparation of the first polymer (A1)

[0234] Synthesis example A1-1-1

[0235] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.02 mol (40 mol%) of diamine compound (b1-a), 0.015 mol (30 mol%) of diamine compound (b1-i), and 0.015 mol (30 mol%) of diamine compound (b1-m), along with 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), were added and stirred at room temperature until dissolved. Next, 0.05 mol (100 mol%) of tetracarboxylic acid dianhydride compound (a1-a) and 20 g of NMP were added, and the reaction was carried out at room temperature for 2 hours. 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 washing and filtration steps were repeated three times with methanol. The product was then placed in a vacuum oven and dried at 60°C to obtain the polymer (A1-1-1) of synthetic example A1-1-1, the formulation of which is shown in Table 1.

[0236] Synthetic Examples A1-1-2 to A1-1-9 and Comparative Synthetic Examples A'1-1-1 to A'1-1-4

[0237] Synthetic Examples A1-1-2 to A1-1-9 and Comparative Synthetic Examples A'1-1-1 to A'1-1-4 used the same preparation method as the polymer (A1-1-1) in Synthetic Example A1-1-1. The difference lies in the type and amount of raw materials used in the polymer. Their formulations are shown in Tables 1 and 2, respectively, and will not be described further here. The compounds corresponding to the numbers in Tables 1 and 2 are shown in Table 3.

[0238] Synthesis example A1-2-1

[0239] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.02 mol (40 mol%) of diamine compound (b1-a), 0.015 mol (30 mol%) of diamine compound (b1-i), and 0.015 mol (30 mol%) of diamine compound (b1-m), along with 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), were added and stirred at room temperature until dissolved. Next, 0.05 mol (100 mol%) of tetracarboxylic acid dianhydride compound (a1-a) and 20 g of NMP were added. After reacting at room temperature for 6 hours, 97 g of NMP, 2.55 g of acetic anhydride, and 19.75 g of pyridine were added, and the temperature was raised to 60 °C and stirred continuously for 2 hours to carry out the acetylation reaction. After the reaction was complete, the reaction solution was poured into 1500 mL of water to allow the polymer to precipitate. The obtained polymer was then filtered, and the washing and filtration with methanol were repeated three times. The polymer was then placed in a vacuum oven and dried at 60°C to obtain polymer (A1-2-1), the formulation of which is shown in Table 1. The compounds corresponding to the numbers in Table 1 are shown in Table 3.

[0240] Synthesis example A1-2-2

[0241] Synthesis Example A1-2-2 uses the same preparation method as the polymer (A1-2-1) in Synthesis Example A1-2-1, except that the types and amounts of raw materials in the polymer are changed. The formulation is shown in Table 1, and will not be described again here. The compounds corresponding to the numbers in Table 1 are shown in Table 3.

[0242] Table 1 Ingredients (Unit: mole%) serial number Synthesis example A1-1-1 A1-1-2 A1-1-3 A1-1-4 A1-1-5 A1-1-6 A1-1-7 A1-1-8 A1-1-9 A1-2-1 A1-2-2 Tetracarboxylic acid dianhydride component (a1) a1-1 Alicyclic tetracarboxylic dianhydride a1-a 100 100 100 100 50 100 50 100 100 a1-b 50 100 a1-2 Other tetracarboxylic dianhydrides a1-c 50 50 a1-d 50 diamine component (b1) b1-1 diamine compounds b1-a 40 15 40 15 b1-b 55 20 b1-c 40 b1-d 40 30 20 b1-e 40 1 40 b1-f b1-g b1-h b1-2 diamine compounds b1-i 30 30 30 30 30 29 30 30 b1-j 30 30 35 b1-3 diamine compounds b1-k 30 40 20 30 10 30 30 b1-l 20 10 b1-4 Other diamine compounds b1-m 30 30 10 30 20 30

[0243] Table 2 Ingredients (Unit: mole%) serial number Synthetic Comparative Example A'1-1-1 A'1-1-2 A'1-1-3 A'1-1-4 Tetracarboxylic acid dianhydride component (a1) a1-1 Alicyclic tetracarboxylic dianhydride a1-a 100 a1-b a1-2 Other tetracarboxylic dianhydrides a1-c 100 100 100 a1-d diamine component (b1) b1-1 diamine compounds b1-a b1-b b1-c b1-d b1-e b1-f 40 b1-g 40 b1-h 40 40 b1-2 diamine compounds b1-i 30 30 30 b1-j 35 b1-3 diamine compounds b1-k 30 b1-l b1-4 Other diamine compounds b1-m 30 30 30

[0244] Table 3 serial number compound Tetracarboxylic dianhydride component (a1) a1-a 1,3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride a1-b 1,2,3,4-Cyclobutane-1,2,3,4-Tetracarboxylic dianhydride a1-c Pyromellitic dianhydride a1-d 3,3',4,4'-benzophenone tetracarboxylic dianhydride (3,3',4,4'-benzophenone tetracarboxylic dianhydride) Diamine component (b1) b1-a (IV-1) b1-b (IV-2) b1-c (IV-3) b1-d (IV-7) b1-e (IV-8) b1-f b1-g b1-h b1-i b1-j b1-k Boc represents t-butyloxy carbonyl. b1-l Boc represents t-butyloxy carbonyl. b1-m

[0245] Preparation of the second polymer (A2)

[0246] Synthesis Examples A2-1-1 to A2-1-3

[0247] Synthetic Examples A2-1-1 to A2-1-3 are prepared using the same method as the polymer (A1-1-1) in Synthetic Example A1-1-1, except that the types and amounts of raw materials in the polymers are changed in Synthetic Examples A2-1-1 to A2-1-3. Their formulations are shown in Table 4, and will not be elaborated further here. The compounds corresponding to the numbers in Table 4 are shown in Table 5.

[0248] Synthesis Examples A2-2-1 to A2-2-2

[0249] Synthetic Examples A2-2-1 to A2-2-2 are prepared using the same method as that used for the polymer (A1-2-1) in Synthetic Example A1-2-1, except that the types and amounts of raw materials used in the polymer are changed. Their formulations are shown in Table 2, and will not be repeated here. The compounds corresponding to the numbers in Table 4 are shown in Table 5.

[0250] Table 4 Ingredients (Unit: mole%) serial number Synthesis example Synthesis example A2-1-1 A2-1-2 A2-1-3 A2-2-1 A2-2-2 Tetracarboxylic acid dianhydride component (a2) a2-a 100 50 100 a2-b 100 50 100 diamine component (b2) b2-a 100 50 100 b2-b 100 50 100

[0251] Table 5 serial number compound Tetracarboxylic dianhydride component (a2) a2-a a2-b Diamine component (b2) b2-a b2-b

[0252] Preparation of liquid crystal alignment agents, liquid crystal alignment films and liquid crystal display elements

[0253] Example 1

[0254] Weigh 50 parts by weight of the polymer (A1-1-1) obtained from synthesis example A1-1-1, 50 parts by weight of the polymer (A2-1-1) obtained from synthesis example A2-1-1, 2000 parts by weight of NMP (B-1), and 500 parts by weight of ethylene glycol n-butyl ether (B-2), and stir and mix them at room temperature to obtain the liquid crystal alignment agent of Example 1.

[0255] The aforementioned liquid crystal alignment agent was spin-coated onto a glass substrate, and a pixel electrode was formed on the glass substrate. The pixel electrode was an IPS driving electrode with a pair of ITO electrodes (electrode width 10 μm, electrode spacing 10 μm, and electrode height 50 nm). The pair of ITO electrodes each had a serrated shape, and the serrated portions of each other were arranged in a separated and interlocking manner. Then, the glass substrate coated with the liquid crystal alignment agent was dried on a heating plate at 80°C for 3 minutes, and then baked in a hot air circulating oven at 250°C for 30 minutes to form a coating film with a thickness of 100 nm.

[0256] A substrate with a liquid crystal alignment film is prepared by irradiating the coated surface with ultraviolet light at a wavelength of 254 nm through a polarizing plate and then baking it in a hot air circulating oven at 250°C for 30 minutes. Similarly, an alignment treatment is applied to a counter substrate, which is a glass substrate without electrodes but with columnar spacers of 4 μm in height.

[0257] The two substrates described above form a set. A sealant is printed on one substrate, and the other substrate is bonded to the other with the liquid crystal alignment film facing each other at 0° alignment. The sealant is then cured to create an empty cell. This empty cell is injected into a liquid crystal MLC-2041 (manufactured by Merck) using a reduced-pressure injection method, and the injection port is sealed to obtain the liquid crystal display element of Example 1. The resulting liquid crystal display element was evaluated using the following methods, and the results are shown in Table 6. The methods for detecting charge mitigation speed and AC image retention will be described later.

[0258] Examples 2 to 12 and Comparative Examples 1 to 4

[0259] Examples 2 to 12 and Comparative Examples 1 to 4 were prepared using the same methods as those used in Example 1 for liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element. The difference was that Examples 2 to 12 and Comparative Examples 1 to 4 changed the types and amounts of raw materials in the liquid crystal alignment agent. Their formulations and evaluation results are shown in Table 6, and will not be repeated here.

[0260] Table 6 Ingredients Unit: parts by weight Example Comparative example 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 First polymer (A1) A1-1-1 50 25 A1-1-2 50 25 A1-1-3 50 A1-1-4 50 A1-1-5 50 A1-1-6 50 A1-1-7 50 A1-1-8 50 A1-1-9 50 A'1-1-1 50 A'1-1-2 50 A'1-1-3 50 A'1-1-4 50 A1-2-1 50 A1-2-2 50 Second polymer (A2) A2-1-1 50 50 50 50 50 50 50 50 A2-1-2 50 50 50 A2-1-3 50 50 50 A2-2-1 50 A2-2-2 50 solvent (B) B-1 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 B-2 500 500 500 500 500 500 500 500 500 500 500 500 500 500 B-3 500 500 High and low temperature shock contrast ※ ※ ※ ◎ ◎ ○ ○ ○ ○ ※ ※ ※ ╳ ╳ ╳ ╳

[0261] Table 7 serial number Element B-1 N-methyl-2-pyrrolidone (NMP) B-2 Ethylene glycol n-butyl ether B-3 N,N-dimethylacetamide

[0262] Evaluation method

[0263] High and low temperature shock contrast

[0264] The manufactured liquid crystal display element was placed in an environment of 60°C and 90% humidity for 1 hour, and then placed in an environment of -20°C for 1 hour. This experimental cycle was repeated 24 times to obtain the desired result.

[0265] Next, using a device with a polarizer and an analyzer positioned between the light source and the light quantity detector, the light transmittance T0 of the blank was measured under crossed nicols / polars conditions; the light transmittance T100 of the blank was measured under parallel nicols conditions; a liquid crystal display element subjected to high and low temperature shocks was positioned between the aforementioned polarizer and analyzer, and the light transmittance B of the liquid crystal display element was measured under crossed nicols conditions.

[0266] The high and low temperature shock dark state relative transmittance (%) is calculated using the above conditions, expressed by the following mathematical formula (1). A lower high and low temperature shock dark state relative transmittance indicates a higher high and low temperature shock contrast ratio, that is, a higher high and low temperature shock contrast ratio indicates better display quality. The high and low temperature shock contrast ratio is evaluated based on the following criteria. Relative transmittance in dark state under high and low temperature impact (%) = (BT 0) / (T 100-T 0)×100(%) (1) ※: Relative transmittance in the dark state under high and low temperature impact (%) ≦ 0.5%. ◎: 0.5% < Relative transmittance in dark state under high and low temperature impact (%) ≦ 0.7%. ○: 0.7% < Relative transmittance in dark state under high and low temperature impact (%) ≦ 1%. ╳: High and low temperature shock dark state relative transmittance (%) > 1%.

[0267] As shown in Table 6, when the first polymer (A1) in Comparative Examples 1 to 4 does not contain the structure shown in Formula (I), the liquid crystal display elements containing the liquid crystal alignment film formed therefrom exhibit poor high and low temperature shock contrast. In contrast, when the first polymer (A1) in Examples 1 to 12 contains the structure shown in Formula (I), the liquid crystal display elements containing the liquid crystal alignment film formed therefrom exhibit good high and low temperature shock contrast.

[0268] When X1 in formula (I) represents the structure shown in formula (I-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has an even higher high and low temperature shock contrast. Secondly, when A1 and A2 in formula (I) are specific divalent organic groups, the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has an even higher high and low temperature shock contrast. When Z1 in formula (I) represents the structure shown in formula (Z1-1-1), the liquid crystal display element containing the liquid crystal alignment film formed by this liquid crystal alignment agent has an even higher high and low temperature shock contrast.

[0269] It should be added that although the present invention uses specific compounds, compositions, reaction conditions, processes, analytical methods, or specific instruments as examples to illustrate the liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element of the present invention, it is clear to anyone with ordinary knowledge in the art that the present invention is not limited thereto. Without departing from the spirit and scope of the present invention, the liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element of the present invention may also be made using other compounds, compositions, reaction conditions, processes, analytical methods, or instruments.

[0270] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the art to which this invention pertains may make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0271] (none)

[0272] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A liquid crystal alignment agent, comprising: a polymer component (A) comprising a first polymer (A1), wherein the first polymer (A1) is selected from at least one of the group consisting of a polyimide precursor and a amide polymer of the polyimide precursor; and a solvent (B), wherein the polyimide precursor of the first polymer (A1) comprises the structure shown in formula (I): (I) In formula (I), X1 is selected from at least one of the group consisting of the structures shown in formulas (I-1) to (I-7), wherein "*" represents a bonding position; X2 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7) In formula (I-1), X11, X12, X13, and X14 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 organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; and in formula (I-7), X15 and X16 independently represent a hydrogen atom or a methyl group; in formula (I), A1 and A2 independently represent divalent organogroups as shown in the following structures, and A1 and A2 do not have the same structure; "*" represents a bond position; in the structures shown above, R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; R5 represents a hydrogen atom, a methyl group, a hydroxyl group, or a methoxy group; In formula (I), Y11 and Y11' independently represent a chain hydrocarbon group or a single bond having 1 to 10 carbon atoms; Y12 and Y12' independently represent -O-, -S-, -OCO-, or -COO-; Y13 and Y13' independently represent a chain hydrocarbon group or a single bond having 1 to 10 carbon atoms; Y11, Y11', Y13, and Y13' are not simultaneously single bonds; Z1 represents the structure shown in formula (Z1-1); (Z1-1) In formula (Z1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 independently has the above definition; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m independently have the above definition; "*" represents the bond position.

2. The liquid crystal alignment agent as described in claim 1, wherein X1 represents the structure shown in formula (I-1-1), and "*" represents the bonding position: (I-1-1).

3. The liquid crystal alignment agent as described in claim 1, wherein Y13 and Y13' represent single bonds.

4. The liquid crystal alignment agent as claimed in claim 1, wherein A1 and A2 each independently represent a divalent organic group as shown in the following structure, and A1 and A2 do not have the same structure, wherein R4 represents an alkyl group having 1 to 5 carbon atoms or -O-; and R5 represents a hydrogen atom, methyl, hydroxyl or methoxy.

5. The liquid crystal alignment agent as described in claim 1, wherein Z1 represents the structure shown in the following formula (Z1-1-1): (Z1-1-1) In this formula (Z1-1-1), R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms; m is an integer from 0 to 4, and when m is an integer from 2 to 4, R1 has the above definition independently; n is an integer from 1 to 3, and when n is 2 or 3, R1 and m have the above definition independently; "*" represents the bond position.

6. The liquid crystal alignment agent as claimed in claim 1, wherein the polymer component (A) further comprises a second polymer (A2), the second polymer (A2) being selected from at least one of the group consisting of a polyimide precursor and a polyimide polymer of the polyimide precursor, and the second polymer (A2) not comprising the structure shown in formula (I).

7. The liquid crystal alignment agent as claimed in claim 6, wherein the polyimide precursor of the second polymer (A2) is obtained by reacting a tetracarboxylic dianhydride component (a2) and a diamine component (b2), the diamine component (b2) comprising a diamine compound (b2-1) having a nitrogen-containing structure, and the nitrogen atom structure in the diamine compound (b2-1) having a nitrogen-containing structure is selected from at least one of the group consisting of nitrogen-containing heterocycles, secondary amine groups and tertiary amine groups.

8. The liquid crystal alignment agent as described in any one of claims 1 to 7, wherein the liquid crystal alignment agent is configured to prepare a liquid crystal alignment film used in a photoalignment process.

9. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 8.

10. A liquid crystal display element comprising a liquid crystal alignment film as described in claim 9.

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