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, and a liquid crystal display element. The liquid crystal alignment agent comprises a polymer (A). Polymer (A) is selected from at least one polymer selected from the group consisting of polyimide precursors and amided polymers of polyimide precursors, wherein the polyimide precursor comprises a structure shown by formula (I). The liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent, under no voltage application, has a 3-fold standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured at 0.0095 or less.

Description

Technical Field

[0001] This invention relates to an alignment agent, an alignment film, and a display element, and more particularly to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. 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 twisted nematic (TN) and vertical alignment (VA), and transverse electric field methods such as in-plane switching (IPS) and fringe field switching (FFS).

[0003] Currently, the most common 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 inhomogeneities within the alignment treatment surface. As an alternative to friction treatment, photoalignment methods are known, which impart alignment capability to the liquid crystal by irradiating 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. Furthermore, the increasingly frequent use of electronic products results in them undergoing frequent cycles of rapid temperature increases and decreases. Such 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] Therefore, how to improve the contrast of liquid crystal alignment films after experiencing multiple high and low temperature extreme environments (i.e., high and low temperature shock contrast) is a problem that those skilled in the art urgently want to solve. Summary of the Invention

[0007] The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film formed by the liquid crystal alignment agent, and a liquid crystal display element comprising the liquid crystal alignment film, wherein the liquid crystal display element has good high and low temperature shock contrast (i.e., the liquid crystal display element has high high and low temperature shock contrast).

[0008] The present invention provides a liquid crystal alignment agent comprising: a polymer (A) selected from at least one polymer selected from the group consisting of a polyimide precursor and a amide polymer of the polyimide precursor, wherein the polyimide precursor comprises a structure represented by the following formula (I). Formula (I) In formula (I), X1 represents at least one of the structures shown in equations (I-1) to (I-7) below; X 2 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A1 represents a divalent organic group. Formula (I-1) Formula (I-2) Formula (I-3) Formula (I-4) Formula (I-5) Formula (I-6) Formula (I-7) In formula (I-1), X11, X12, X13, and X14 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; * indicates a bond position, and at least one of X11, X12, X13, and X14 is not a hydrogen atom; In equations (I-2) to (I-6), * indicates the location of the bond; In formula (I-7), X15 and X16 each independently represent a hydrogen atom or a methyl group, and * indicates the bond position. The standard deviation (3σ) of the distribution of intra-pixel ellipticity retardation of a liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent is less than 0.0095 when no voltage is applied.

[0009] In one embodiment of the present invention, the liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent, under no voltage application, has a three-times standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured to be 0.0085 or less.

[0010] In one embodiment of the present invention, X1 above represents the structure shown by formula (I-1-1), Formula (I-1-1) The asterisk (*) indicates the location of the bond.

[0011] In one embodiment of the present invention, A1 above represents at least one selected from the group consisting of the structures shown in formula (II-1) and formula (II-2). Equation (II-1) In formula (II-1), A2 and A3 each independently represent a monovalent organic group; m and n each independently represent integers from 0 to 4; a represents an integer from 1 to 6; * indicates the location of the bond. Equation (II-2) In formula (II-2), A4 and A5 each independently represent a monovalent organic group; Ar represents a substituted or unsubstituted divalent aromatic ring group, wherein the aromatic ring in the divalent aromatic ring group is a benzene ring, biphenyl, or naphthalene ring; p and q each independently represent integers from 0 to 4; r and s each independently represent integers from 1 to 3; * indicates the location of the bond.

[0012] In one embodiment of the present invention, A1 above represents the structure shown by formula (II-1).

[0013] The present invention provides a liquid crystal alignment film for photoalignment, which is formed using the above-mentioned liquid crystal alignment agent.

[0014] The present invention provides a liquid crystal alignment film formed using the above-mentioned liquid crystal alignment agent.

[0015] The present invention provides a liquid crystal display element comprising: the liquid crystal alignment film described above.

[0016] Based on the above, the present invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. By limiting the three-fold standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay of the liquid crystal display element containing the liquid crystal alignment agent to 0.0095 or less under no voltage application, the liquid crystal display element containing the liquid crystal alignment agent has good high and low temperature shock contrast. Simple Explanation of the Diagram

[0017] none Implementation

[0018] [<] [Liquid crystal alignment agent] [>]

[0019] This embodiment provides a liquid crystal alignment agent, wherein the liquid crystal alignment agent comprises a polymer (A). Furthermore, the liquid crystal alignment agent may further comprise a polymer (B), a solvent (C), an additive (D), or a combination thereof.

[0020] In this embodiment, the standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay of the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent is less than 0.0095, preferably less than 0.0085, when no voltage is applied.

[0021] When the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has a three-times standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured under no voltage application, the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has good high and low temperature shock contrast and good display quality.

[0022] Conversely, when the distribution of elliptic polarization delay within pixels of a liquid crystal display element containing the liquid crystal alignment agent formed by the liquid crystal alignment film is measured under no voltage application and the three-fold standard deviation (3σ) is greater than 0.0095, the liquid crystal display element containing the liquid crystal alignment agent formed by the liquid crystal alignment film has low high and low temperature shock contrast and poor display quality.

[0023] When the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has a three-times standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured under no voltage application, 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) and better display quality.

[0024] In one embodiment, the liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent has a three-times standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured under no voltage application, which is greater than or equal to 0.

[0025] Specifically, the method for obtaining three times the standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay of a liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent is as follows: [(] [1] Fabrication of liquid crystal display elements

[0026] There are no particular limitations on the liquid crystal display elements to which the liquid crystal alignment film formed by the liquid crystal alignment agent in this embodiment is applicable. Liquid crystal display elements can be, for example, longitudinal electric field types such as twisted nematic (TN) and vertical alignment (VA), or transverse electric field types such as planar switching (IPS) and edge field switching (FFS). It is noteworthy that when the liquid crystal display element type differs, the three-times-standard-deviation (3σ) of the measured intra-pixel elliptic polarization delay distribution remains approximately the same. That is, the three-times-standard-deviation (3σ) of the intra-pixel elliptic polarization delay distribution does not substantially change due to the type of liquid crystal display element.

[0027] The following example only illustrates the application of a liquid crystal display element with a liquid crystal alignment film formed by a liquid crystal alignment agent in an in-plane switching (IPS) mode, but this embodiment is not limited to this. Specifically, the method for manufacturing the liquid crystal display element is as follows:

[0028] 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 having 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 comb-like shape, and the comb-like 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.

[0029] 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, a substrate with a liquid crystal alignment film is obtained. In this way, the first unit can be formed.

[0030] Similarly, an alignment film is formed on a counter substrate using the liquid crystal alignment agent prepared as described above, and an alignment treatment is applied. The counter substrate is a glass substrate without electrodes but having columnar spacers with a height of 4 μm. In this way, a second unit can be formed.

[0031] The first and second units are considered as a group. A sealant is printed on one of them, while the other is bonded together with the liquid crystal alignment film facing each other and aligned at 0°, separated by a spacer (cell gap). The sealant is then cured to obtain an empty cell. This empty cell is then injected with liquid crystal (e.g., MLC-2041 (manufactured by Merck)) using a depressurized injection method, and the injection hole is sealed to obtain a liquid crystal display element for testing.

[0032] From the projection of each element of the liquid crystal display element in the stacking direction, the liquid crystal display element has a first pixel region where pixel electrodes exist and a second pixel region where pixel electrodes do not exist. [(] [2] [Method for measuring the distribution of elliptic polarization delay within pixels]

[0033] The fabricated liquid crystal display element was placed on the measuring stage of an AxoStep device manufactured by AXOMETRICS. Without applying voltage, the distribution of elliptic polarization delay within the pixel (i.e., the distribution of elliptic polarization delay in the second pixel region) was measured at 550 nm. The elliptic polarization delay distribution map within the pixel was plotted using AxoStep Viewer software (X-axis: δ deg, elliptic polarization delay angle; Y-axis: N, cumulative number). The standard deviation (3σ) of the elliptic polarization delay distribution within the pixel was obtained. The cumulative number refers to the number of pixels of the AxoStep device in the manually selected test area (this is a different concept from the pixels of the liquid crystal display element). [polymer(] [A] [)]

[0034] The polymer (A) in this embodiment is selected from at least one polymer from the group consisting of polyimide precursors and amide polymers of the polyimide precursors.

[0035] The polyimide precursor comprises the structure shown in formula (I). Formula (I) In formula (I), X1 represents at least one of the structures shown in equations (I-1) to (I-7) below; X 2 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A1 represents a divalent organic group. Formula (I-1) Formula (I-2) Formula (I-3) Formula (I-4) Formula (I-5) Formula (I-6) Formula (I-7) In formula (I-1), X11, X12, X13, and X14 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group; * indicates a bond position, and at least one of X11, X12, X13, and X14 is not a hydrogen atom; In equations (I-2) to (I-6), * indicates the location of the bond; In formula (I-7), X15 and X16 each independently represent a hydrogen atom or a methyl group, and * indicates the bond position.

[0036] The above X1 represents the structure shown in equation (I-1-1). Formula (I-1-1) The asterisk (*) indicates the location of the bond.

[0037] When X1 represents the structure shown in Equation (I-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 (i.e., higher high and low temperature shock contrast).

[0038] In one embodiment, A1 above represents at least one selected from the group consisting of the structure shown in formula (II-1) and the structure shown in formula (II-2), preferably representing the structure shown in formula (II-1). Equation (II-1) In formula (II-1), A2 and A3 each independently represent a monovalent organic group; m and n each independently represent integers from 0 to 4; a represents an integer from 1 to 6; * indicates the location of the bond. Equation (II-2) In formula (II-2), A4 and A5 each independently represent a monovalent organic group; Ar represents a substituted or unsubstituted divalent aromatic ring group, wherein the aromatic ring in the divalent aromatic ring group is a benzene ring, biphenyl, or naphthalene ring; p and q each independently represent integers from 0 to 4; r and s each independently represent integers from 1 to 3; * indicates the location of the bond.

[0039] When A1 represents at least one of the group consisting of the structures shown in formula (II-1) and formula (II-2) above, 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).

[0040] When A1 represents the structure shown in the above formula (II-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).

[0041] The polymer (A) in this embodiment can be selected from at least one polymer in the group consisting of polyimide precursors obtained by reacting tetracarboxylic dianhydride component (a1) and diamine component (a2), and amide polymers of polyimide precursors. For example, polymer (A) is a polyimide precursor having a amide precursor structure such as polyamide acid and polyamide ester, or polymer (A) is an amide polymer (i.e., polyimide) formed from the above-mentioned polyimide precursor, or polymer (A) comprises the above-mentioned polyimide precursor and the above-mentioned amide polymer.

[0042] 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 (a2-1). Furthermore, the polyimide precursor of polymer (A1) may further include, but is not limited to, other structural units other than those shown in formula (I) formed by any one of the tetracarboxylic dianhydrides (a1) and any one of the diamines (a2) described later, which will not be elaborated further here. Tetracarboxylic dianhydride component (a1)

[0043] In this embodiment, the tetracarboxylic dianhydride component (a1) reacting with the diamine component (a2) can be a tetracarboxylic dianhydride compound, or a tetracarboxylic dianhydride derivative such as a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide. The tetracarboxylic dianhydride component (a1) can be a single tetracarboxylic dianhydride compound or its derivative, or a combination of multiple compounds.

[0044] The tetracarboxylic dianhydride component (a1) may comprise an alicyclic tetracarboxylic dianhydride (a1-1). The tetracarboxylic dianhydride component (a1) may optionally further comprise other tetracarboxylic dianhydrides (a1-2). Alicyclic tetracarboxylic dianhydride (a1-1)

[0045] The tetracarboxylic dianhydride component (a1) used to react and obtain polymer (A) may comprise an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof represented by formula (A11). The alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof represented by formula (A11) may be composed of a single tetracarboxylic dianhydride or a derivative thereof, or may be composed of multiple tetracarboxylic dianhydrides or their derivatives. In this embodiment, the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) may, for example, be an acid dianhydride obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group bonded to an alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Alternatively, it may not be necessary to consist solely of an alicyclic structure; a portion of it may also have a chain hydrocarbon structure or an aromatic ring structure. Equation (A11) In equation (A11), X1 can be selected from at least one of the groups consisting of the structures shown in equations (I-1) to (I-7), and * indicates the bond position.

[0046] Formula (I-1) Formula (I-2) Formula (I-3) Formula (I-4) Formula (I-5) Formula (I-6) Formula (I-7)

[0047] In formula (I-1), X11, X12, X13, and X14 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organogroup having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and * indicates the bond position. It is worth noting that X11, X12, X13, and X14 may be the same or different, and at least one of X11, X12, X13, and X14 is not a hydrogen atom.

[0048] In equations (I-2) to (I-6), * indicates the location of the bond.

[0049] In formula (I-7), X15 and X16 each independently represent a hydrogen atom or a methyl group, and * indicates the bond position.

[0050] In some embodiments, X1 may represent the structure shown by equations (I-1-1) to (I-1-5). Formula (I-1-1) Formula (I-1-2) Formula (I-1-3) Formula (I-1-4) Formula (I-1-5)

[0051] In formula (A11), X1 preferably represents the structure shown in formula (I-1), and 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. Furthermore, 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.

[0052] When X 1 represents the group shown in formula (I-1-1), the alicyclic tetracarboxylic dianhydride (a1-1) is the tetracarboxylic dianhydride shown in formula (I-1-1a). Equation (I-1-1a)

[0053] The total amount of tetracarboxylic dianhydride component (a1) used is 100 mol, and the amount of alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11) used is 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0054] When the tetracarboxylic dianhydride component (a1) does not contain the alicyclic tetracarboxylic dianhydride (a1-1) shown in formula (A11), 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, resulting in poor display quality of the liquid crystal display element. Other tetracarboxylic dianhydrides (a1-2)

[0055] Other tetracarboxylic dianhydrides (a1-2) may include tetracarboxylic dianhydride compounds and their derivatives represented by the following formula (A12).

[0056] Equation (A12)

[0057] In equation (A12), X 1' can represent the structure shown in equations (A12-1) to (A12-32), where * indicates the bond position.

[0058] Equation (A12-1) In equation (A12-1), a1 represents an integer from 1 to 12. Equation (A12-2) Equation (A12-3) Equation (A12-4) Equation (A12-5) In formula (A12-5), X 11' represents a single bond, -O-, -CO-, -COO-, phenyl, sulfonyl, or amino group, and a1 represents an integer of 0 or 1. Equation (A12-6) In formula (A12-6), X11' and X12' each independently represent a single bond, -O-, -CO-, -COO-, phenyl, sulfonyl, or amino group, and multiple X12's may be the same or different from each other, and a1 represents an integer of 0 or 1. Equation (A12-7) Equation (A12-8) Equation (A12-9) Equation (A12-10) Equation (A12-11) In formula (A12-11), a1 represents an integer from 2 to 6. Equation (A12-12) Equation (A12-13) In equation (A12-13), a1 represents an integer of 1 or 2. Equation (A12-14) In formulas (A12-14), each 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 organogroup 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, X 13' preferably represents a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably represents a hydrogen atom or a methyl group. Equation (A12-15) Equation (A12-16) Equation (A12-17) Equation (A12-18) Equation (A12-19) Equation (A12-20) Equation (A12-21) Equation (A12-22) Equation (A12-23) Equation (A12-24) Equation (A12-25) Equation (A12-26) Equation (A12-27) Equation (A12-28) Equation (A12-29) Equation (A12-30) Equation (A12-31) Equation (A12-32)

[0059] In one embodiment, the structures shown in formula (A12-5) and formula (A12-6) may include, but are not limited to, the structures shown in formulas (A12-5-1) to (A12-5-9) and formulas (A12-6-1) to (A12-6-7).

[0060] The structure shown in formula (A12-5) is preferably the structure shown in formula (A12-5-1) or formula (A12-5-6). Equation (A12-5-1) Equation (A12-5-2) Formula (A12-5-3) Equation (A12-5-4) Formula (A12-5-5) Equation (A12-5-6) Formula (A12-5-7) Formula (A12-5-8) Equation (A12-6-1) Equation (A12-6-2) Equation (A12-6-3) Equation (A12-6-4) Equation (A12-6-5) Equation (A12-6-6) Equation (A12-5-9) Equation (A12-6-7)

[0061] The aforementioned other tetracarboxylic dianhydrides (a1-2) can be used alone or in combination.

[0062] The total amount of tetracarboxylic dianhydride component (a1) used is 100 mol, and the amount of other tetracarboxylic dianhydrides (a1-2) used is 0 to 70 mol, preferably 0 to 60 mol, and even more preferably 0 to 50 mol.

[0063] Based on the total mole count of the diamine component (a2) described later being 100 moles, the amount of the tetracarboxylic acid dianhydride component (a1) used can range from 20 moles to 200 moles, preferably from 30 moles to 120 moles. [Diamine component()] [a2] [)]

[0064] The diamine component (a2) may include diamine compound (a2-1). In addition to diamine compound (a2-1), the diamine component (a2) may optionally further include diamine compound (a2-2), diamine compound (a2-3), diamine compound (a2-4), other diamine compounds (a2-5), or combinations thereof. [Diamine compounds () [a2-1] [)]

[0065] The diamine compound (a2-1) may comprise at least one of the diamine compounds represented by formula (II-1a) and formula (II-2a). The diamine compound (a2-1) is preferably a diamine compound represented by formula (II-1a).

[0066] Equation (II-1a) In formula (II-1a), A2 and A3 each independently represent a monovalent organic group; m and n each independently represent integers from 0 to 4; a represents an integer from 1 to 6; * indicates the location of the bond.

[0067] Equation (II-2a) In formula (II-2a), A4 and A5 each independently represent a monovalent organic group; Ar represents a substituted or unsubstituted divalent aromatic ring group, wherein the aromatic ring in the divalent aromatic ring group is a benzene ring, biphenyl, or naphthalene ring; p and q each independently represent integers from 0 to 4; r and s each independently represent integers from 1 to 3; * indicates the location of the bond.

[0068] Specific examples of diamine compounds represented by formula (II-1a) may include at least one of the groups represented by formulas (II-1-1) to (II-1-4), preferably the groups represented by formulas (II-1-2) to (II-1-4).

[0069] Equation (II-1-1) Equation (II-1-2) Equation (II-1-3) Equation (II-1-4)

[0070] In formula (II-2a), the monovalent substituent group that Ar represents on the benzene ring, biphenyl ring, or naphthyl ring may be, for example, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 3 carbon atoms, a cyano group, or a nitro group, preferably a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

[0071] The monovalent substituents on the benzene ring bonded by the aforementioned two amino groups can be, for example, the monovalent substituents listed in the Ar group above, and the preferred embodiments are as described above.

[0072] For example, the divalent aromatic ring group represented by Ar may include, but is not limited to, 1,4-epimine, 1,3-epimine, 2-methyl-1,4-epimine, 2-ethyl-1,4-epimine, 2-propyl-1,4-epimine, 2-isopropyl-1,4-epimine, 2-methoxy-1,4-epimine, 2-ethoxy-1,4-epimine, 2-propoxy-1,4-epimine, 2-fluoro-1,4-epimine, 2,3-dimethyl-1,4-epimine, 4-methyl-1,3-epimine, 5-methyl-1,3-epimine, 4-fluoro-1,3-epimine, 2,3,5,6-tetramethyl-1,4-epimine, biphenyl-4,4'-diyl, 2-methylbiphenyl-4,4'-diyl, 2-ethylbiphenyl-4,4'-diyl, 2-Propylbiphenyl-4,4'-diyl, 2-methoxybiphenyl-4,4'-diyl, 2-ethoxybiphenyl-4,4'-diyl, 2-fluorobiphenyl-4,4'-diyl, 3-methylbiphenyl-4,4'-diyl, 3-ethylbiphenyl-4,4'-diyl, 3-propylbiphenyl-4,4'-diyl, 3-methoxybiphenyl-4,4'-diyl, 3-ethoxybiphenyl-4, 4'-diyl, 3-fluorobiphenyl-4,4'-diyl, 2,2'-dimethylbiphenyl-4,4'-diyl, 3,3'-dimethylbiphenyl-4,4'-diyl, biphenyl-3,3'-diyl, 5-methylbiphenyl-3,3'-diyl, 5,5'-dimethylbiphenyl-3,3'-diyl, 1,5-pennaphthyl, 2,6-pennaphthyl or 1-methyl-2,6-pennaphthyl.

[0073] Specific examples of diamine compounds represented by formula (II-2a) may include at least one of the groups represented by formulas (II-2-1) to (II-2-3), preferably at least one of the groups represented by formulas (II-1-1) and (II-1-2).

[0074] Equation (II-2-1) In equation (II-2-1), m and n each independently represent integers from 1 to 3. Equation (II-2-2) In equation (II-2-2), m and n each independently represent integers from 1 to 3. Equation (II-2-3) In equation (II-2-3), m and n each independently represent integers from 1 to 3.

[0075] In formulas (II-2-1) to (II-2-3), any hydrogen atom on the benzene ring bonded to the two amine groups, or any hydrogen atom on the divalent benzene ring, biphenyl, or naphthalene ring bonded to the alkyl group, can be replaced by a monovalent substituent group, such as the monovalent substituent group listed above as the Ar group, and the preferred embodiments are as described above. The definitions of m and n are as described above.

[0076] Specific examples of the diamine compounds represented by formula (II-2a) may include the diamine compounds represented by formula (II-2-4), the diamine compounds represented by formula (II-2-5), or combinations thereof. Equation (II-2-4) Equation (II-2-5)

[0077] For example, the diamine compound represented by formula (II-2-4) can be synthesized using the method disclosed in the journal article published on May 17, 2011, in Volume 994, Issue 1-3, pages 242-247; the diamine compound represented by formula (II-2-5) can be synthesized using the method disclosed in the journal article published on October 5, 2018, in Volume 1169, pages 46-58.

[0078] The aforementioned diamine compound (a2-1) can be used alone or in combination.

[0079] When the diamine compound (a2-1) includes at least one of the diamine compounds represented by formula (II-1a) and formula (II-2a), the liquid crystal display element comprising 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).

[0080] When the diamine compound (a2-1) is the diamine compound represented by formula (II-1a), 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).

[0081] When the diamine compound (a2-1) is a diamine compound represented by formula (II-1-2), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has particularly good high and low temperature shock contrast (i.e., particularly high high and low temperature shock contrast).

[0082] Based on the total amount of diamine component (a2) used being 100 mol, the amount of diamine compound (a2-1) used can be from 10 mol to 90 mol, preferably from 11 mol to 70 mol, and even more preferably from 12 mol to 60 mol. [Diamine compounds () [a2-2] [)]

[0083] The diamine compound (a2-2) may comprise a diamine compound represented by the following formula (A22). Equation (A22) In formula (A22), Z 31 and Z 31' each independently represent a chain-like hydrocarbon group or a single bond with 1 to 10 carbon atoms; Z 32 and Z 32' each independently represent -O-, -S-, -CO-, or -COO-; Z 33 and Z 33' each independently represent a chain hydrocarbon group or a single bond with 1 to 10 carbon atoms; Z 31, Z 31', Z 33, and Z 33' cannot all be single bonds; Ring Z represents an aromatic hydrocarbon ring, a diphenyl ether, or a nitrogen-containing heterocycle; B1 and B2 each independently represent one of the divalent organogroups selected from formulas (A22-a) to (A22-p) below, and B1 and B2 do not have the same structure. Equation (A22-a) Equation (A22-b) Equation (A22-c) Equation (A22-d) Equation (A22-e) Equation (A22-f) Formula (A22-g) Equation (A22-h) Equation (A22-i) Equation (A22-j) Equation (A22-k) Formula (A22-l) Equation (A22-m) Equation (A22-n) Equation (A22-o) Equation (A22-p) In equations (A22-a) to (A22-p), * indicates the bond position. In formula (A22-b), B3 represents an alkyl group with 1 to 5 carbon atoms or -O-; In formula (A22-n), B4 represents a hydrogen atom, methyl, hydroxyl, or methoxy group.

[0084] In some embodiments, the diamine compound (a2-2) represented by formula (A22) is selected from at least one of the groups consisting of the structures represented by formulas (A22-a) and (A22-b).

[0085] Equation (A22-1) Equation (A22-2)

[0086] The definitions of Z31 and Z31 in equations (A22-1) and (A22-2) are the same as those in equation (A22), and will not be repeated here.

[0087] The diamine compound (a2-2) may include, but is not limited to, compounds represented by formulas (A22-3) to (A22-5), preferably including compounds represented by formula (A22-4), compounds represented by formula (A22-5), or combinations thereof. Equation (A22-3) Equation (A22-4) Equation (A22-5)

[0088] The compounds represented by the aforementioned formula (A22-4) can be prepared by the following method.

[0089] Step 1: Add 13.9 g (0.1 mol) of reactant A (4-nitrophenol); The reactant was reacted with 26.4 g (0.1 mole) of product B (1,4-bis(bromomethyl)benzene). 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. ).

[0090] Step 2: 32.2 g (0.1 mol) of the first intermediate was reacted with 21.5 g (0.1 mol) of reactant C (4-nitro-4'-hydroxybiphenyl). Dissolve the product in 1 L of ACN, then add 27.6 g (0.2 mol) of potassium carbonate to form a mixture. Stir the mixture at 79 °C for 3 hours, and then filter after the reaction. Next, wash the reaction product at 50 °C for 1 hour with a mixed solution of 500 g water and 150 g methanol. Then, cool, filter, and vacuum dry to obtain the second intermediate product. ).

[0091] Step 3: Dissolve 45.6 g (0.1 mol) of the second intermediate in 2.5 L of a mixed solution containing THF and ethanol, 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 compound shown in formula (A22-4).

[0092] The compound shown in formula (A22-3) can be prepared using the same method and reactant ratio as the compound shown in formula (A22-4). The difference lies in the fact that reactant B used in the compound shown in formula (A22-3) is 1,4-bis(2-bromoethyl)benzene. Therefore, different first intermediate products are obtained. ) and the second intermediate ( ).

[0093] The compound shown in formula (A22-5) can be prepared using the same method and reactant ratio as the compound shown in formula (A22-4). The difference lies in the reactant C used in the compound shown in formula (A22-5), which is 4-(4-nitrophenoxy)phenol. Therefore, different second intermediate products are obtained. ).

[0094] The aforementioned diamine compound (a2-2) can be used alone or in combination.

[0095] Based on the total amount of diamine component (a2) used being 100 mol, the amount of diamine compound (a2-2) used can be from 0 mol to 90 mol, preferably from 12.5 mol to 80 mol, and even more preferably from 15 mol to 70 mol. [Diamine compounds () [a2-3] [)]

[0096] The diamine compound (a2-3) may comprise at least one of the diamine compounds shown in formulas (A23-1) and (A23-2). The diamine compound is preferably a diamine compound shown in formula (A23-1).

[0097] Equation (A23-1) Equation (A23-2)

[0098] In formula (A23-1), Y 31 represents a divalent organic group as shown in formula (A23-3). Each of the plurality of Y 32 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. In formula (A23-2), each of the plurality of Y 33 independently represents a divalent organic group as shown in formula (A23-3').

[0099] Equation (A23-3) Equation (A23-3')

[0100] In formula (A23-3), 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 may be substituted by a monovalent substituent or remain unsubstituted; Y 31' represents -(CH 2) n-, where n represents an integer from 2 to 18, and at least one -CH 2- in -(CH 2) n- may be substituted by -O-, -C(=O)-, or -OC(=O)- or remain unsubstituted; p1 represents an integer of 0 or 1; * represents the bond position. Formula (A23-3) excludes compounds where Ar represents a benzene ring, and Y 31' represents -(CH 2) n-, where n represents an integer from 3 to 18, and two -CH 2- in -(CH 2) n- are substituted by -O-.

[0101] In formula (A23-3'), 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 an integer of 0 or 1; * represents the bond position.

[0102] The monovalent substituents of the aforementioned benzene ring, biphenyl structure, or naphthalene ring may be, for example, halogen atoms, 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, the divalent organic group shown in formula (A23-3) preferably includes at least one of the groups shown in formula (A23-3-1) to formula (A23-3-13), where * indicates the bonding position.

[0104] Equation (A23-3-1) In equation (A23-3-1), m is 0 to 1 and n is 1 to 6. Equation (A23-3-2) In formula (A23-3-2), n ranges from 1 to 6. Equation (A23-3-3) In formula (A23-3-3), n ranges from 2 to 6. Equation (A23-3-4) In formula (A23-3-4), n ranges from 1 to 6. Equation (A23-3-5) In formula (A23-3-5), n ranges from 1 to 6. Equation (A23-3-6) In formula (A23-3-6), n ranges from 2 to 6. Equation (A23-3-7) In formula (A23-3-7), n is 1 to 6. Formula (A23-3-8) In formula (A23-3-8), n ranges from 2 to 6. Equation (A23-3-9) In equation (A23-3-9), m is 1 to 3 and n is 1 to 4. Formula (A23-3-10) In formula (A23-3-10), n is 1 to 6. Equation (A23-3-11) In formula (A23-3-11), m is 1 to 3 and n is 1 to 4. Equation (A23-3-12) Equation (A23-3-13)

[0105] In one embodiment, the diamine compound represented by formula (A23-1) is preferably represented by Y 31, which represents the group represented by formula (A23-3-10) or the group represented by formula (A23-3-12), and more preferably by Y 31, which represents the group represented by formula (A23-3-10).

[0106] Specifically, when Y 31 represents the group shown in formula (A23-3-10), the diamine compound is, for example, the diamine compound shown in formula (A23-3-10a). Formula (A23-3-10a)

[0107] When Y 31 represents the group shown in formula (A23-3-12), the diamine compound is, for example, the diamine compound shown in formula (A23-3-12a). Equation (A23-3-12a)

[0108] When the diamine compound (a2-3) comprises a plurality of diamine compounds represented by formula (A23-1), it is preferably a combination formed by Y 31 in formula (A23-1) representing at least one of the diamine compounds of formulas (A23-3-1) to (A23-3-14) and Y 31 in formula (A23-1) representing at least one of the diamine compounds of formulas (A23-3-15) to (A23-3-16).

[0109] In one embodiment, the diamine compound represented by formula (A23-2) may include, but is not limited to, the diamine compounds represented by formulas (A23-2-1) to (A23-2-5), and the diamine compound represented by formula (A23-2) preferably includes the diamine compound represented by formula (A23-2-1). Equation (A23-2-1) In equation (A23-2-1), m is 1 to 6 and n is 1 to 6. Equation (A23-2-2) In formula (A23-2-2), m is 1 to 6 and n is 1 to 6. Equation (A23-2-3) In formula (A23-2-3), m is 2 to 6 and n is 2 to 6. Equation (A23-2-4) Equation (A23-2-5)

[0110] The aforementioned diamine compounds (a2-3) can be used alone or in combination.

[0111] Based on the total amount of diamine component (a2) used being 100 mol, the amount of diamine compound (a2-3) used can be from 0 mol to 90 mol, preferably from 10 mol to 85 mol, and even more preferably from 15 mol to 80 mol. [Diamine compounds () [a2-4] [)]

[0112] Based on the viewpoint of further reducing the number of bright spots in liquid crystal display elements, the molecular structure of polymer (A) can selectively have -N(D)- groups (where D represents a carbamate-based protecting group). In other words, when the molecular structure of polymer (A) has -N(D)- groups, the resulting liquid crystal alignment film has better hardness, thus resulting in a higher minimum number of friction cycles in abrasion resistance tests, which can further improve the bright spot problem caused by scratches on the liquid crystal alignment film in liquid crystal display elements.

[0113] The polymer (A) having a -N(D)- group can be obtained by using a monomer having a -N(D)- group as at least a portion of the reactants, or by using it as a capping agent as described later. In some specific examples, the monomer having a -N(D)- group can be, for example, a diamine compound (a2-4) having a -N(D)- group. For example, the carbamate protecting group may include, but is not limited to, a tributoxycarbonyl or a 9-pyromethoxycarbonyl. The carbamate protecting group is preferably a tributoxycarbonyl.

[0114] Preferably, the diamine compound (a2-4) having a -N(D)- group comprises a diamine compound having at least one aromatic group such as a benzene ring. More preferably, the diamine compound (a2-4) having a -N(D)- group comprises a diamine compound having at least one aromatic group such as a benzene ring, and the residues other than the substituent (D) are diamine compounds having 6 to 30 carbon atoms.

[0115] In some specific examples, the diamine compound (a2-4) having a -N(D)- group may include, but is not limited to, the diamine compounds shown in formulas (A24-1) to (A24-11). In formulas (A24-1) to (A24-11), Boc is t-butyloxy carbonyl. The diamine compound (a2-4) having a -N(D)- group is preferably the diamine compound shown in formula (A24-8). Equation (A24-1) Equation (A24-2) Equation (A24-3) Equation (A24-4) Equation (A24-5) Equation (A24-6) Equation (A24-7) Equation (A24-8) Equation (A24-9) Equation (A24-10)

[0116] The aforementioned diamine compounds (a2-4) can be used alone or in combination.

[0117] Based on the total amount of diamine component (a2) used being 100 mol, the amount of diamine compound (a2-4) used can be from 0 mol to 90 mol, preferably from 10 mol to 85 mol, and even more preferably from 15 mol to 80 mol. [Other diamine compounds() [a2-5] [)]

[0118] The diamine component (a2) may also selectively include other diamine compounds (a2-5). For example, other diamine compounds (a2-5) may include, but are not limited to: 4,4'-diaminoazobenzene or diamine compounds with photoalignment groups such as those shown in formulas (A25-1) to (A25-3); 2,4-diaminophenol, 2,5-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, or 4,6-diaminoresorcinol; 2 4-Diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds having a carboxyl group, such as diamine compounds of formulas (A25-4) to (A25-7); 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ketone, 1,4-bis(4-aminobenzyl)benzene, 4,4 '-Diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine or 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamine compounds having a urea bond, such as diamine compounds of formulas (A25-8) to (A25-10); diamine compounds having a urea bond, such as diamine compounds of formulas (A25-11) to (A25-13). Diamine compounds with amine bonds; diamine compounds with photopolymerizable groups at the end, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines having siloxane bonds, such as 3-bis(3-aminopropyl)-tetramethyldisiloxane; diamine compounds with an oxazoline structure, such as diamine compounds of formulas (A25-14) to (A25-15); or combinations thereof. Other diamine compounds (a2-5) are preferably diamine compounds of formula (A25-8).

[0119] Equation (A25-1) Equation (A25-2) Equation (A25-3) Equation (A25-4) In formula (A25-4), 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. Equation (A25-5) In equation (A25-5), m3 and m4 each independently represent integers from 1 to 5. Equation (A25-6) In formula (A25-6), Y 52 represents a straight-chain or branched alkyl group with 1 to 5 carbon atoms; m5 represents an integer from 1 to 5. Equation (A25-7) In formula (A25-7), Y53 and Y54 each independently represent a single bond, -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. Equation (A25-8) In equation (A25-8), n1 represents an integer from 0 to 6, and n2 represents an integer from 1 to 6. Equation (A25-9) In equation (A25-9), n1 represents an integer from 1 to 6, and n2 represents an integer from 1 to 6. Equation (A25-10) In equation (A25-10), n represents an integer from 1 to 6. Equation (A25-11) Equation (A25-12) In equation (A25-12), n represents an integer from 1 to 6. Equation (A25-13) In equation (A25-13), n1 represents an integer from 1 to 6, and n2 represents an integer from 1 to 6. Equation (A25-14) Equation (A25-15)

[0120] The other diamine compounds (a2-5) mentioned above can be used alone or in combination.

[0121] The total amount of diamine component (a2) used is 100 mol, and the amount of other diamine compounds (a2-5) used can be 0 mol to 90 mol, preferably 10 mol to 85 mol, and even more preferably 15 mol to 80 mol. [polymer(] [B] [)]

[0122] In some embodiments, the liquid crystal alignment agent further comprises a polymer (B).

[0123] Polymer (B) is selected from at least one of the group consisting of polyimide precursors formed by reacting a reaction composition comprising a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and amide polymers formed from the aforementioned polyimide precursors. It is noteworthy that polymer (B) does not contain the structure represented by formula (I) in polymer (A). For example, polymer (B) is a polyimide precursor having a polyamide and polyamide ester amide precursor structure, or polymer (B) is an amide polymer (i.e., polyimide) formed from a polyimide precursor, or polymer (B) comprises the aforementioned polyimide precursor and the aforementioned amide polymer, etc. Polymer (B) may be used alone or in combination.

[0124] In other embodiments, the weight ratio of polymer (A) to polymer (B) (i.e., the mass ratio of polymer (A) to polymer (B)) is 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and even more preferably 20 / 80 to 80 / 20. [Tetracarboxylic dianhydride component ()] [b1] [)]

[0125] The tetracarboxylic dianhydride component (b1) includes, but is not limited to, noncyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, aromatic tetracarboxylic dianhydride compounds, or derivatives of these compounds. Noncyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, and aromatic tetracarboxylic dianhydride compounds include, for example, tetracarboxylic dianhydride compounds in polymer (A). Preferably, the tetracarboxylic dianhydride component (b1) 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 X1' represents the structure shown in formulas (A12-1) to (A12-6). The above-described tetracarboxylic dianhydride component (b1) may be used alone or in combination.

[0126] Preferably, the tetracarboxylic dianhydride component (b1) comprises a tetracarboxylic dianhydride compound (a2-1) with the structure shown in formula (B1) and X1' having the structure shown in formula (B1-a). Equation (B1-a).

[0127] In equation (B1-a), Z 11 represents a single bond, and * represents the bond position.

[0128] Tetracarboxylic dianhydride (a2-1) can be used alone or in combination.

[0129] More preferably, the above-mentioned tetracarboxylic dianhydride component (b1) includes the tetracarboxylic dianhydride compound shown in formula (B1-a-1), the tetracarboxylic dianhydride compound shown in formula (B1-a-2), or a combination thereof.

[0130] Equation (B1-a-1) Equation (B1-a-2).

[0131] In one embodiment, based on the total amount of tetracarboxylic acid dianhydride component (b1) being 100 mol, the amount of 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.

[0132] Based on the total mole count of the diamine component (b2) described later being 100 moles, the amount of the tetracarboxylic acid dianhydride component (b1) used can range from 20 moles to 200 moles, preferably from 30 moles to 120 moles. [Diamine component()] [b2] [)]

[0133] The diamine component (b2) is, for example, a diamine compound (a2-2), diamine compound (a2-3), diamine compound (a2-4), other diamine compounds (a2-5), diamine compound (b2-1) having a nitrogen-containing structure, or a combination thereof, in the diamine component (a2) of polymer (A), excluding diamine compound (a1-1). The diamine component (b2) described above can be used alone or in combination. [Diamine compounds () [b2-1] [)]

[0134] 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.

[0135] 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 aforementioned nitrogen-containing heterocycle is pyridine, pyrimidine, pyridine, piperidine, piperidine, quinoline, carbazole, or acridine.

[0136] The nitrogen-containing structure of the diamine compound (b2-1) with nitrogen-containing atomic structures is represented by secondary and tertiary amino groups as shown in formula (B21). Formula (B21).

[0137] In formula (B21), Z represents hydrogen, alkyl, cycloalkyl or aryl with 1 to 10 carbon atoms; * represents the bond position.

[0138] The alkyl groups having 1 to 10 carbon atoms are, for example, but not limited to, methyl, ethyl, or propyl. The cycloalkyl groups are, for example, but not limited to, cyclohexyl. The aryl groups are, for example, but not limited to, phenyl or tolyl. Preferably, Z is hydrogen or methyl.

[0139] The diamine compound (b2-1) having a nitrogen-containing structure is, for example, but 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). The diamine compound (b2-1) having a nitrogen-containing structure is preferably the diamine compound of formula (B21-1). Equation (B21-1) Equation (B21-2) Equation (B21-3) Equation (B21-4) Equation (B21-5) In equation (B21-5), n represents 1 to 4. Equation (B21-6) In equation (B21-6), n represents 1 to 4. Equation (B21-7) Equation (B21-8) Equation (B21-9) Equation (B21-10) Equation (B21-11) Equation (B21-12) Equation (B21-13) Equation (B21-14) Equation (B21-15) Equation (B21-16) Equation (B21-17) Equation (B21-18) Equation (B21-19) Formula (B21-20) Equation (B21-21) Equation (B21-22) Equation (B21-23) Equation (B21-24) Equation (B21-25) Equation (B21-26)

[0140] Diamine compounds (b2-1) with nitrogen-containing structures can be used alone or in combination.

[0141] In one embodiment, the diamine compound (b2-1) having a nitrogen-containing atomic structure is preferably the diamine compound shown in formula (B21-1), and is used in combination with the diamine compound shown in formula (B14-3-15a).

[0142] In one embodiment, based on the total amount of the above-mentioned diamine component (b2) being 100 mol, 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. [polymer(] [A] [) and polymers (] [B] Preparation method of [ )

[0143] Polymer (A) can be prepared by carrying out a (condensation polymerization) reaction of the aforementioned tetracarboxylic dianhydride component (a1) and diamine component (a2) in a solvent. Polymer (B) can be prepared by carrying out a (condensation polymerization) reaction of the aforementioned diamine component (b1) and tetracarboxylic dianhydride component (b2) in a solvent. When a portion of polymer (A) or polymer (B) 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 polymer formed. For example, specific examples of solvents may include, but are not limited to, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or 1,3-dimethyl-2-imidazolidineone. A preferred example of a solvent is N-methyl-2-pyrrolidone. In one embodiment, when the polymer has high solvent solubility, the solvent may include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by formulas (AS-1) to (AS-3).

[0144] Formula (AS-1) In formula (AS-1), Z1 represents an alkyl group having 1 to 3 carbon atoms. Formula (AS-2) In formula (AS-2), Z2 represents an alkyl group having 1 to 3 carbon atoms. Formula (AS-3) In formula (AS-3), Z 3 represents an alkyl group having 1 to 4 carbon atoms.

[0145] The aforementioned solvents can be used alone or in combination. Furthermore, even solvents that cannot dissolve the polymer can still be mixed with the aforementioned solvents within a range where the resulting polymer will not precipitate. When the diamine component and the tetracarboxylic dianhydride component react in the solvent, the reaction can proceed at any concentration, but preferably from 1 wt% to 50 wt%, and more preferably from 5 wt% to 30 wt%. The reaction can also be initially carried out at a high concentration, with additional solvent added later. During the reaction, the ratio of the total moles of the diamine component to the total moles of the tetracarboxylic dianhydride component is preferably 0.8 to 1.2. Similar to general polycondensation reactions, the closer this mole ratio is to 1.0, the larger the molecular weight of the resulting polymers (A) and (B).

[0146] Polymers having a polyamide ester structure can be obtained, for example, by conventional methods such as: (1) reacting the polyamide obtained by the above method 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.

[0147] The amide compound in polymer (A) or polymer (B) contained in the liquid crystal alignment agent of this embodiment can be obtained, for example, by cyclizing the aforementioned polymer. In the above-mentioned amide compound, the cyclization rate (also known as the amide ratio) of the functional groups of the amide group or its derivatives does not necessarily have to be 100%, and its amide ratio can be arbitrarily adjusted according to the application and / or purpose.

[0148] Methods for obtaining amides include, for example, thermal amide amide by directly heating the polymer solution obtained from the above reaction, or catalytic amide amide by adding a catalyst to the polymer solution. When thermal amide amide is carried out in solution, the temperature is preferably between 100°C and 400°C, and more preferably between 120°C and 250°C. During thermal amide amide amide, it is preferable to remove the water generated by the amide amide reaction from the system.

[0149] The aforementioned catalytic acetylation can be carried out, for example, by adding a basic catalyst and an acid anhydride to the polymer solution obtained from the reaction, preferably at a temperature of -20°C to 250°C, and more preferably at a temperature of 0°C to 180°C with stirring. The amount of basic catalyst added is preferably 0.5 to 30 times the molar equivalent of the acetic acid groups, and more preferably 2 to 20 times; the amount of acid anhydride added is preferably 1 to 50 times the molar equivalent of the acetic acid groups, and more preferably 3 to 30 times. Specific examples of basic catalysts include, but are not limited to, pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine. Pyridine is preferred because it has a moderately basic nature that allows the reaction to proceed. Specific examples of acid anhydrides include, but are not limited to, acetic anhydride, trimellitic anhydride, or phenylmethyltetrahydroquinone. Acetic anhydride is preferred because purification after the reaction is easier. The amide rate of catalytic amide can be controlled by adjusting the amount of catalyst, reaction temperature, and / or reaction time.

[0150] When recovering the amide formed from the above-mentioned amide reaction solution, the reaction solution is added to a solvent and precipitated. The solvent used for precipitation may include, but is not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, or water. After filtering and recovering the polymer precipitated in the solvent, it can be dried at room temperature or under normal or reduced pressure. Alternatively, the polymer recovered from precipitation can be dissolved again in a solvent and reprecipitated; this operation can be repeated 2 to 10 times to reduce impurities in the polymer. The solvent used may be, for example, alcohols or ketone hydrocarbons. Using three or more of the selected solvents can further improve the purification efficiency, which is ideal. [Polymer solution viscosity and molecular weight]

[0151] When preparing a solution with a concentration of 10 wt% to 15 wt%, the solution viscosity of polymer (A) or polymer (B) in this embodiment 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 type E rotational viscometer after preparing a polymer solution with a concentration of 10 wt% to 15 wt% using a good solvent for the above polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone).

[0152] In this embodiment, the weight-average molecular weight (Mw) of polymer (A) or polymer (B), as measured by gel permeation chromatography (GPC) and converted from polystyrene, is preferably from 1,000 to 500,000, and more preferably from 2,000 to 500,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene as measured by GPC, is preferably 15 or less, and more preferably 10 or less. When the molecular weight of the polymer is within the aforementioned range, good alignment and stability of the liquid crystal display element can be ensured. [End-capping agent]

[0153] When synthesizing polymer (A) or polymer (B) of this embodiment, the tetracarboxylic dianhydride component and diamine component as described above can be used, and an end-sealed polymer can be synthesized using a suitable end-sealing agent. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating, and improving the adhesion properties between the sealant and the liquid crystal alignment film. The ends of polymer (A) or polymer (B) of this embodiment may, for example, contain amine groups, carboxyl groups, anhydride groups, or derivatives thereof. Amine 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 later. Similarly, the aforementioned derivatives can be obtained, for example, using the end-sealing agent described below.

[0154] For example, the capping agent may include, but is not limited to, acid anhydrides such as 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-ethynyl phthalic anhydride; and dibutyl dicarbonate or diallyl dicarbonate, etc. Acrylic acid diester compounds; chlorocarbonyl compounds such as acrylonitrile chloride, methacrylamide chloride, or nicotinamide chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, or n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, or naphthyl isocyanate, etc.

[0155] The capping agent can be used alone or in combination.

[0156] Based on the total amount of diamine components used being 100 mol, the amount of capping agent used is preferably from 0.01 mol to 20 mol, and more preferably from 0.01 mol to 10 mol. [Other polymers]

[0157] The liquid crystal alignment agent of this embodiment may optionally include other polymers (A3). Other polymers may include, for example, but are not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates, etc. [solvent() [C] [)]

[0158] The liquid crystal alignment agent of this embodiment may optionally further include solvent (C). From the viewpoint of forming a uniform thin film, the liquid crystal alignment agent is taken in the form of a coating liquid to produce a liquid crystal alignment film. The liquid crystal alignment agent of this embodiment is preferably a coating liquid containing the aforementioned polymer (A) and solvent (C). The concentration of polymer (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 polymer (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 polymer (A) in the liquid crystal alignment agent is preferably 10 wt% or less. Ideally, the concentration of polymer (A) can be from 2 wt% to 8 wt%. The content of polymer (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, and is preferably from 2 wt% to 10 wt%, and more preferably from 3 wt% to 7 wt%.

[0159] The solvent (C) in the liquid crystal alignment agent is, for example, an organic solvent, and there are no particular limitations on the solvent (C) contained in the liquid crystal alignment agent, as long as it can uniformly dissolve the aforementioned polymer. Specific examples may include, but are 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. The solvents mentioned above include 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, and N-cyclohexyl-2-pyrrolidone, etc., and these organic solvents are also called good solvents. Among them, 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. The total amount of solvent used in the liquid crystal alignment agent is 100 wt%, and the amount of good solvent used can be from 20 wt% to 99 wt%, preferably from 20 wt% to 90 wt%, and even more preferably from 30 wt% to 80 wt%.

[0160] Secondly, the organic solvent in the liquid crystal alignment agent is preferably a mixed solvent, using the aforementioned solvent and a solvent that can improve the coatability and surface smoothness of the coating film during liquid crystal alignment agent coating (also known as a lean solvent). The specific solvents used may include, but are not limited to, those described later. Based on a total solvent usage of 100 wt% in the liquid crystal alignment agent, the amount of lean solvent used is preferably 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 lean solvent can be appropriately selected based on the coating apparatus, coating conditions, and / or coating environment of the liquid crystal alignment agent.

[0161] For example, lean solvents may include: 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 ceroxysulfate, ethylene glycol n-butyl ether), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxy) 2-(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.

[0162] Among them, 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 are preferred.

[0163] A preferred solvent combination of good and poor solvents may include, but is 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-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 dipropylene 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.

[0164] Specific examples of solvent (C) are preferably N-methyl-2-pyrrolidone (NMP), ethylene glycol n-butyl ether, N,N-dimethylacetamide, or combinations thereof.

[0165] The aforementioned solvent (C) can be used alone or in combination.

[0166] Based on 100 parts by weight of polymer (A) and 800 to 4000 parts by weight of solvent (C), preferably 900 to 3500 parts by weight, and even more preferably 1000 to 3000 parts by weight. [additive(] [D] [)]

[0167] In this embodiment, the liquid crystal alignment agent may also selectively contain components other than polymers and organic solvents (hereinafter referred to as additives (D)). These additives (D) may include, for example, but are not limited to: an adhesion promoter (D-1) for improving the adhesion between the liquid crystal alignment film and the substrate or between the liquid crystal alignment film and the sealant; a crosslinking compound for improving the strength of the liquid crystal alignment film (hereinafter referred to as crosslinking compound (D-2)); a compound for promoting amide imidization (D-3); and a dielectric or conductive material for adjusting the dielectric constant or resistance of the liquid crystal alignment film. Sealing agent (D-1)

[0168] The aforementioned sealing aid (D-1) may be, for example, 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, vinyltrimethoxysilane, etc. Silane coupling agents including methoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, or 3-isocyanate propyltriethoxysilane.

[0169] The aforementioned sealing agent (D-1) can be used alone or in combination.

[0170] The amount of binding agent (D-1) used is preferably from 0.1 to 30 parts by weight, and more preferably from 0.1 to 20 parts by weight, relative to the total amount of polymer (A) used in the liquid crystal alignment agent being 100 parts by weight. Cross-linking compound (D-2)

[0171] For the aforementioned crosslinking compounds, based on the viewpoint of exhibiting good resistance to AC remnants and effectively improving film strength, they may be compounds having ethylene oxide, propylene oxide, at least one group selected from the group consisting of the group shown in formula (d2-a) and the group shown in formula (d2-b), or compounds selected from the compounds shown in formula (d2-c).

[0172] Equation (d2-a) In formula (d2-a), G1 and G2 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH2-OH. Equation (d2-b) In formula (d2-b), 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. Equation (d2-c) In formula (d2-c), G5 represents an organic group with an aromatic ring and a (g1+g2) valence. G6 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms, g1 represents an integer from 1 to 6, and g2 represents an integer from 0 to 4.

[0173] In formula (d2-c), the (g1+g2) valence organic group represented by G 5 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 (d2-c), the alkyl group represented by G 6 with 1 to 5 carbon atoms can be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, dibutyl, terbutyl, or n-pentyl. [Compounds containing ethylene oxide]

[0174] 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 (d2-1) to (d2-3).

[0175] Equation (d2-1) Equation (d2-2) Equation (d2-3) [Compounds containing propylene oxide]

[0176] Specific examples of compounds having an alkylene oxide group can be listed as compounds represented by formulas (d2-4) to (d2-13).

[0177] Equation (d2-4) Equation (d2-5) Equation (d2-6) Equation (d2-7) Equation (d2-8) Equation (d2-9) Equation (d2-10) Equation (d2-11) Equation (d2-12) Equation (d2-13)

[0178] In formula (d2-12), R represents the group shown in formula (d2-12-1), where * indicates the bond position.

[0179] Equation (d2-12-1) [Has the expression ()] [d2-a] Compounds with groups indicated by [)

[0180] Specific examples of compounds having the group shown in formula (d2-a) can be the compounds shown in formulas (d2-a-1) to (d2-a-12). Equation (d2-a-1) Equation (d2-a-2) Equation (d2-a-3) Equation (d2-a-4) Equation (d2-a-5) Equation (d2-a-6) Equation (d2-a-7) Equation (d2-a-8) Equation (d2-a-9) Equation (d2-a-10) Equation (d2-a-11) Equation (d2-a-12) [Has the expression ()] [d2-b] Compounds with groups indicated by [)

[0181] Specific examples of compounds having the group shown in formula (d2-b) can be the compounds shown in formulas (d2-b-1) to (d2-b-4). Equation (d2-b-1) Equation (d2-b-2) Equation (d2-b-3) Equation (d2-b-4) [Has the expression ()] [d2-c] Compounds with groups indicated by [)

[0182] Specific examples of compounds having the group shown by formula (d2-c) can be the compounds shown by formulas (d2-c-1) to (d2-c-10). Equation (d2-c-1) Equation (d2-c-2) Equation (d2-c-3) Equation (d2-c-4) Equation (d2-c-5) Equation (d2-c-6) Equation (d2-c-7) Equation (d2-c-8) Equation (d2-c-9) Equation (d2-c-10)

[0183] The aforementioned cross-linking compound (D-2) can be used alone or in combination.

[0184] In this embodiment of the liquid crystal alignment agent, based on the total amount of polymer used in the liquid crystal alignment agent being 100 parts by weight, the amount of crosslinking compound (D-2) 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 (D-2) used is more preferably 1 part by weight to 15 parts by weight. Compounds that promote aceimination (D-3)

[0185] The aforementioned compound (D-3) for promoting aceimination is preferably a compound 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 compound (D-2) and binding aid (D-1)), or a compound that generates the basic site upon heating. More preferably, the compound (D-3) for promoting aceimination is a compound that generates the basic site upon heating, 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, histamine, lysine, or ornithine. For the purpose of promoting aceimination of compounds (D-3), a more specific example can be listed as N-α-(9-enylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0186] The aforementioned compound (D-3) that promotes aceiminization can be used alone or in combination. < [Fabrication methods of liquid crystal alignment films and liquid crystal display elements]

[0187] This embodiment provides a liquid crystal alignment film formed using the liquid crystal alignment agent as described above.

[0188] This embodiment also provides a liquid crystal alignment film for photoalignment, formed using the above-described liquid crystal alignment agent.

[0189] This embodiment provides a liquid crystal display element, comprising the liquid crystal alignment film as described above.

[0190] The liquid crystal alignment film of this embodiment is obtained from the aforementioned liquid crystal alignment agent. The liquid crystal alignment film of this embodiment can be 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 this embodiment includes the aforementioned liquid crystal alignment film. The liquid crystal display element of this embodiment can be manufactured, for example, by the following steps (1) to (4) or steps (1) to (2) and (4).

[0191] Step (1): Apply liquid crystal alignment agent to the substrate.

[0192] The liquid crystal alignment agent of this embodiment 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 coating. 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.

[0193] Methods for coating liquid crystal alignment agents onto a substrate to form a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray coating. Among these, inkjet coating is the preferred method for film formation.

[0194] Step (2): Heat the coated liquid crystal alignment agent

[0195] Step (2) is to heat 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 or the polyamide or polyamide ester can be thermally amided using heating means such as a hot plate, a thermal cycling oven, or an infrared (IR) oven. The drying and heating steps performed after coating the liquid crystal alignment agent of this embodiment can be selected at any temperature and time, and multiple drying or heating 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 amided polyamide or polyamide ester, after the aforementioned drying step, a heating 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 heating time, which can be listed as 5 to 40 minutes or 5 to 30 minutes. If the heated 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.

[0196] Step (3): Perform alignment treatment on the membrane obtained in step (2).

[0197] 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 above-mentioned 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 Polymer Stabilized Alignment (PSA) mode, the formed coating can be used directly as a liquid crystal alignment film, but these coatings 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 (also known as "photoalignment method"), with photoalignment treatment being preferred. Photoalignment treatment can include irradiating the surface of the above-mentioned 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 property (also known as liquid crystal alignment capability). The radiation may be ultraviolet light or visible light with wavelengths from 100 nm to 800 nm. Preferably, the radiation is ultraviolet light with wavelengths from 100 nm to 400 nm, and more preferably ultraviolet light with wavelengths from 200 nm to 400 nm.

[0198] The irradiation dose of the aforementioned radiation can be from 1 mJ / cm² to 10,000 mJ / cm², preferably from 100 mJ / cm² to 5,000 mJ / cm², 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 general liquid crystal alignment agent, the irradiation dose of the alignment treatment is from 100 mJ / cm² to 5000 mJ / cm². During irradiation, to improve the liquid crystal alignment, the substrate of the aforementioned film can be heated at 50°C to 250°C simultaneously with the irradiation. The liquid crystal alignment film prepared in this manner allows the liquid crystal molecules to be stably aligned in a certain direction. Furthermore, the liquid crystal alignment film irradiated with polarized radiation in the aforementioned method can be contacted with a solvent or subjected to heat treatment.

[0199] 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. 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. One solvent or a mixture of several solvents can be used alone.

[0200] The preferred temperature for heat treatment of the aforementioned irradiated coating is 50°C to 300°C, and more preferably 120°C to 250°C. The preferred heat treatment time is 1 minute to 30 minutes.

[0201] Step (4): Fabrication of liquid crystal cells

[0202] 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 spacer (intercellular space). Then, bond the peripheral portions 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.

[0203] 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. Then, liquid crystal composition is dropped onto multiple predetermined positions on the liquid crystal alignment film surface. Next, the other substrate is bonded with the liquid crystal 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. Then, 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 used to a temperature that becomes isotropic, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling. Furthermore, when performing a rubbing treatment on the coating, the two substrates are arranged facing each other at a predetermined angle with the rubbing directions of each coating, for example, orthogonal or antiparallel. The sealant can be, for example, epoxy resin containing a hardener and alumina spheres as spacers. The liquid crystal used, i.e., liquid crystal compound or liquid crystal composition, is not particularly limited here. Liquid crystal components may include nematic liquid crystals and lamellar liquid crystals, with nematic liquid crystals being more preferred.

[0204] 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.

[0205] The present invention will be further illustrated by the following experimental examples, but it should be understood that these experimental examples are for illustrative purposes only and should not be construed as limiting the implementation of the present invention. [polymer(] [A] [Example of synthesis of (polyamide)] [Synthesis example] [A-1-1]

[0206] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.0075 mol (50 mol%) of diamine compound (a2-a), 0.00225 mol (15 mol%) of diamine compound (a2-f), 0.00075 mol (5 mol%) of diamine compound (a2-h), 0.003 mol (20 mol%) of diamine compound (a2-i), and 0.0015 mol (10 mol%) of diamine compound (a2-j), along with 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), were added and stirred at room temperature until dissolved. Next, 0.015 mol (100 mol%) of a1-a and 20 g of NMP, which are tetracarboxylic dianhydrides, were added, and the reaction was carried out at room temperature for 2 hours. 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 washed with methanol and filtered three times. Afterward, the polymer was placed in a vacuum oven and dried at 60°C to obtain polymer (A-1-1). Here, polymer (A-1-1) is a polyimide precursor (i.e., polyamic acid (PAA)), and the tetracarboxylic dianhydride and diamine components of the synthesized polymer (A-1-1) are shown in Table 1. [Synthesis example] [A-1-2] to [A-1-10]

[0207] The polymers (A-1-2) to (A-1-10) of Synthetic Examples A-1-2 to A-1-10 were prepared using the same steps as in Synthetic Example A-1-1, except that the types and amounts of the diamine and tetracarboxylic dianhydride components in Synthetic Example A-1-1 were changed (as shown in Table 1). In Table 1, the amount of each component is expressed in "moles %", and the actual number of moles used is calculated by setting 0.015 moles to 100 moles %. For detailed usage ratios, please refer to Synthetic Example A-1-1. The compounds corresponding to the abbreviations in Table 1 are shown in Table 2. It is worth noting that in Table 2, a1-a' are compounds used as comparative examples. [polymer(] [A] Synthesis example of (polyimide) [Synthesis example] [A-2-1]

[0208] A nitrogen inlet, stirrer, condenser, and thermometer were installed on a 500 mL four-necked conical flask, and nitrogen gas was introduced. Then, 0.0075 mol (50 mol%) of diamine compound (a2-a), 0.00225 mol (15 mol%) of diamine compound (a2-f), 0.00075 mol (5 mol%) of diamine compound (a2-h), 0.003 mol (20 mol%) of diamine compound (a2-i), and 0.0015 mol (10 mol%) of diamine compound (a2-j), along with 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), were added and stirred at room temperature until dissolved. Next, 0.015 mol (100 mol%) of a1-a, which is a tetracarboxylic dianhydride component, 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 mixture was heated to 60 °C and stirred continuously for 2 hours to carry out the amide reaction. After the amide reaction was completed, the reaction solution was poured into 1500 mL of water to allow the polymer to precipitate. The obtained polymer was then filtered and washed with methanol and filtered three times. The polymer was then placed in a vacuum oven and dried at 60 °C to obtain polymer (A-2-1). Here, polymer (A-2-1) is a polyamide, and the tetracarboxylic acid dianhydride and diamine components of the synthesized polymer (A-2-1) are shown in Table 1. [Synthesis example] [A-2-2]

[0209] The polymer (A-2-2) of Synthetic Example A-2-2 was prepared by the same steps as that of Synthetic Example A-2-1, except that the types and amounts of the diamine and tetracarboxylic acid dianhydride components of Synthetic Example A-2-1 were changed (as shown in Table 1). [polymer(] [A'] Comparative synthetic examples of [ ] (polyamide)

[0210] The polymers (A'-1) to (A'-2) of the comparative synthetic examples A'-1 to A'-2 were prepared using the same steps as those of synthetic example A-1-1, except that the types and amounts of the diamine and tetracarboxylic dianhydride components in synthetic example A-1-1 were changed (as shown in Table 1).

[0211] Table 1 Ingredients (Unit: moles%) Synthesis example Comparative Synthesis Examples Synthesis example A-1-1 A-1-2 A-1-3 A-1-4 A-1-5 A-1-6 A-1-7 A-1-8 A-1-9 A-1-10 A'-1 A'-2 A-2-1 A-2-2 Tetracarboxylic acid dianhydride component (A1) a1-a 100 100 50 100 100 100 50 100 100 50 100 100 a1-a' 100 50 a1-b 50 50 50 a1-c 50 diamine component (A2) a2-a 50 30 10 50 50 a2-b 50 a2-c 30 30 a2-d 25 a2-e 15 a2-f 15 15 30 50 15 15 15 15 a2-g 25 25 30 30 15 15 25 a2-h 5 20 5 20 50 20 45 15 5 15 5 20 a2-i 20 25 10 20 25 20 5 20 25 40 20 40 20 25 a2-j 10 80 10 25 10 15 10 15 10

[0212] Table 2 Abbreviation compound Tetracarboxylic dianhydride component (a1) a1-a Equation (I-1-1a) 1,3-Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride a1-a' 1,2,3,4-Cyclobutane-1,2,3,4-Tetracarboxylic dianhydride a1-b Pyromellitic dianhydride a1-c 3,3',4,4'-benzophenone tetracarboxylic dianhydride (3,3',4,4'-benzophenone tetracarboxylic dianhydride) Diamine component (a2) a2-a Equation (II-1-2) a2-b Equation (II-1-4) a2-c Equation (II-1-3) a2-d Equation (II-2-4) a2-e Equation (II-2-5) a2-f Equation (A22-4) a2-g Equation (A22-5) a2-h a2-i Equation (A24-8a) a2-j Equation (A25-8a) [polymer(] [B] Example of synthesis of [)] [Example of polyacrylic acid synthesis] [B-1-1] to [B-1-2]

[0213] The second polymers (B-1-1) to (B-1-2) of Synthetic Examples B-1-1 to B-1-2 were prepared using the same steps as in Synthetic Example A-1-1, except that the types and amounts of the diamine and tetracarboxylic dianhydride components used in Synthetic Example A-1-1 were changed (as shown in Table 3). In Table 3, the amount of each component is expressed in "moles %", and the actual number of moles used is calculated by setting 0.015 moles as 100 moles %. The compounds corresponding to the abbreviations in Table 3 are shown in Table 4. [Example of polyimide synthesis] [B-2-1] to [B-2-2]

[0214] The second polymers (B-2-1) to (B-2-2) of Synthetic Examples B-2-1 to B-2-2 were prepared using the same steps as in Synthetic Example A-2-1, except that the types and amounts of the diamine and tetracarboxylic dianhydride components used in Synthetic Example A-2-1 were changed (as shown in Table 3). In Table 3, the amount of each component is expressed in "moles %", and the actual number of moles used is calculated by setting 0.015 moles as 100 moles %. The compounds corresponding to the abbreviations in Table 3 are shown in Table 4.

[0215] Table 3 Ingredients (Unit: moles%) Synthesis example Synthesis example B-1-1 B-1-2 B-2-1 B-2-2 Tetracarboxylic acid dianhydride component (B1) b1-a 100 100 b1-b 100 100 diamine component (B2) b2-a 100 100 b2-b 100 100

[0216] Table 4 Abbreviation compound Tetracarboxylic dianhydride component (b1) b1-a 4,4'-oxydiphthalic anhydride b1-b 3,3',4,4'-Biphenyltetracarboxylic anhydride Diamine component (b2) b2-a 4,4'-Diaminodiphenylamine b2-b p-phenylenediamine [Examples and Comparative Examples of Liquid Crystal Alignment Agents]

[0217] The following describes experimental examples 1 to 14 and comparative examples 1 to 2 of liquid crystal alignment agents: [Experimental Example] [1] [a.] [Liquid crystal alignment agent]

[0218] Weigh 50 parts by weight of polymer (A-1-1), 50 parts by weight of polymer (B-1-1), 1000 parts by weight of N-methyl-2-pyrrolidone (referred to as C-1), and 450 parts by weight of ethylene glycol n-butyl ether (referred to as C-2), and mix them by stirring at room temperature to form the liquid crystal alignment agent of Experimental Example 1. [b.] Liquid crystal display element

[0219] 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 having 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 comb-like shape, and the comb-like 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.

[0220] 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, a substrate with a liquid crystal alignment film is obtained. In this way, the first unit can be formed.

[0221] Similarly, an alignment film is formed on a counter substrate using the liquid crystal alignment agent prepared as described above, and an alignment treatment is applied. The counter substrate is a glass substrate without electrodes but having columnar spacers with a height of 4 μm. In this way, a second unit can be formed.

[0222] The first and second units are considered as a group. A sealant is printed on one of them, while the other is bonded together with the liquid crystal alignment film facing each other and aligned at 0°, separated by a spacer (cell gap). The sealant is then cured to obtain an empty cell. This empty cell is injected into liquid crystal MLC-2041 (manufactured by Merck) using a depressurized injection method, and the injection hole is sealed to obtain the liquid crystal display element of Example 1.

[0223] The liquid crystal display element of Experiment Example 1 was evaluated using the evaluation methods described below, and the results are shown in Table 5. [Experimental Example] [2] [To the experimental example]

[14] [And comparative examples] [1] [To the comparative example] [2]

[0224] The liquid crystal alignment agents and liquid crystal display elements of Experimental Examples 2 to 14 and Comparative Examples 1 to 2 were prepared using the same steps as in Experimental Example 1, except that the types and amounts of the components were changed, as shown in Table 5. The liquid crystal display elements prepared in Experimental Examples 2 to 14 and Comparative Examples 1 to 2 were evaluated using the evaluation methods described below, and the results are shown in Table 5. The compounds corresponding to the abbreviations in Table 5 are shown in Table 6.

[0225] Table 5 Ingredients Unit: parts by weight Example (PAA) Example (PI) Examples (PAA and PI) Comparative example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 combination (A) A-1-1 50 twenty five twenty five A-1-2 50 twenty five A-1-3 50 A-1-4 50 A-1-5 50 A-1-6 50 A-1-7 50 A-1-8 50 A-1-9 50 A-1-10 50 A-2-1 50 twenty five A-2-2 50 combination (A') A'-1 50 A'-2 50 combination (B) B-1-1 50 50 50 50 50 50 twenty five 50 50 B-1-2 50 50 50 50 50 B-2-1 50 25 B-2-2 50 solvent (C) C-1 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 100 100 500 1000 1000 C-2 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 C-3 900 900 500 Three times the standard deviation (3σ) of the elliptic polarization delay within a pixel. 0.006 0.005 0.005 0.008 0.007 0.008 0.007 0.009 0.009 0.009 0.006 0.005 0.007 0.005 0.018 0.02 High and low temperature shock contrast ※ ※ ※ ◎ ◎ ◎ ◎ ○ ○ ○ ※ ※ ◎ ※ X X

[0226] Table 6 Abbreviation Element A-1-1 Polymer (A-1-1) A-1-2 Polymer (A-1-2) A-1-3 Polymer (A-1-3) A-1-4 Polymer (A-1-4) A-1-5 Polymer (A-1-5) A-1-6 Polymer (A-1-6) A-1-7 Polymer (A-1-7) A-1-8 Polymer (A-1-8) A-1-9 Polymer (A-1-9) A-1-10 Polymer (A-1-10) A'-1 Polymer (A'-1) A'-2 Polymer (A'-2) A-2-1 Polymer (A-2-1) A-2-2 Polymer (A-2-2) B-1-1 Polymer (B-1-1) B-1-2 Polymer (B-1-2) B-2-1 Polymer (B-2-1) B-2-2 Polymer (B-2-2) C-1 N-Methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) C-2 Ethylene glycol n-butyl ether (ethylene glycol n-butyl ether,BCS, CAS No.:111-76-2 C-3 γ-Butyrolactone (gamma-Butyrolactone,GBL,CAS No.:96-48-0) [[] [Evaluation Method] []] [a.] [Obtained from the distribution of elliptical polarization delay within pixels] [3] [Multiple standard deviations ()] [3σ] [)]

[0227] The method for obtaining the 3x standard deviation (3σ) obtained from the detailed distribution of elliptical polarization delay within pixels is as described above and will not be repeated here. [b.] [High and Low Temperature Shock Contrast]

[0228] 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 in an experimental cycle. This experimental cycle was repeated 24 times to obtain a liquid crystal display element after high and low temperature shock.

[0229] 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.

[0230] 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 (%) --------- Mathematical formula (1)

[0231] ※: 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%. [[] [Evaluation Results] []]

[0232] As shown in Table 5, when the standard deviation (3σ) of the distribution of intrapixel elliptic polarization delay of the liquid crystal display element containing the liquid crystal alignment agent formed under no voltage application is greater than 0.0095 (Comparative Examples 1 to 2), the high and low temperature shock contrast of the liquid crystal display element containing the liquid crystal alignment agent formed is poor.

[0233] Compared to polymers (A') in liquid crystal alignment agents that do not contain the structure shown in Formula (I) (Comparative Examples 1 to 2), when polymers (A) in liquid crystal alignment agents are limited to containing the structure shown in Formula (I) (Experimental Examples 1 to 14), liquid crystal display elements containing liquid crystal alignment films formed by liquid crystal alignment agents have good high and low temperature shock contrast.

[0234] When the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has a three-fold standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured under no voltage application (Examples 1 to 7 and Examples 11 to 14), 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.

[0235] When A1 in formula (I) of polymer (A) represents at least one of the group consisting of the structures shown in formula (II-1) and formula (II-2) (Examples 1 to 7 and 11 to 14), 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.

[0236] When A1 in formula (I) of polymer (A) is the structure shown by formula (II-1) (Experimental Examples 1 to 3 and Experimental Examples 11, 12 and 14), 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.

[0237] In summary, this embodiment provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. By defining polymer (A) in polymer (A) as including the structure shown in formula (I) and the structure shown in formula (II), the liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent has good high and low temperature shock contrast.

[0238] none

Claims

1. A liquid crystal alignment agent comprising: a polymer (A) selected from at least one polymer selected from the group consisting of a polyimide precursor and acetamipridated polymers of the polyimide precursor, the polyimide precursor comprising the structure shown in formula (I); and a polymer (B) selected from at least one polymer selected from the group consisting of a polyimide precursor and acetamipridated polymers of the polyimide precursor, and not comprising the structure shown in formula (I), Formula (I) In formula (I), X1 represents the structure shown in formula (I-1-1); X2 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A1 represents at least one selected from the group consisting of the structures shown in formula (II-1) and formula (II-2), Formula (I-1-1) In formula (I-1-1), * represents a bond position; Formula (II-1) In formula (II-1), A2 and A3 each independently represent a monovalent organic group; m and n each independently represent an integer from 0 to 4; a represents an integer from 1 to 6; * represents a bond position. In formula (II-2), A4 and A5 each independently represent a monovalent organic group; Ar represents a substituted or unsubstituted divalent aromatic ring group, wherein the aromatic ring in the divalent aromatic ring group is a benzene ring, biphenyl, or naphthalene ring; p and q each independently represent an integer from 0 to 4; r and s each independently represent an integer from 1 to 3; * represents a bond position. The 3-fold standard deviation (3σ) of the distribution of elliptic polarization delay within pixels of a liquid crystal display element containing the liquid crystal alignment film formed by the liquid crystal alignment agent, measured under no voltage application, is 0.0095 or less. The 3-fold standard deviation (3σ) of the distribution of elliptic polarization delay within pixels is measured by the following method: A first unit formation step involves coating the liquid crystal alignment agent onto a first substrate having pixel electrodes to form a liquid crystal alignment film, thereby forming the first unit; a second unit formation step involves coating the liquid crystal alignment agent onto a second substrate without electrodes to form a liquid crystal alignment film, thereby forming the second unit; a sealing step involves printing a sealant onto one of the first unit and the second unit, while bonding and injecting liquid crystal onto the other of the first unit and the second unit such that the liquid crystal alignment films face each other and the alignment direction is 0°, to obtain the liquid crystal display element; and a measurement step involves measuring the distribution of elliptic polarization delay in a second pixel region of the liquid crystal display element where the pixel electrodes are not present without applying voltage, and plotting its elliptic polarization delay distribution map to obtain three times the standard deviation (3σ) of the distribution of elliptic polarization delay within the pixel.

2. The liquid crystal alignment agent as claimed in claim 1, wherein the liquid crystal display element comprising the liquid crystal alignment film formed by the liquid crystal alignment agent, under no voltage application, has a three-fold standard deviation (3σ) of the distribution of intra-pixel elliptic polarization delay measured to be 0.0085 or less.

3. The liquid crystal alignment agent as claimed in claim 1, wherein A1 represents the structure shown in formula (II-1).

4. A liquid crystal alignment film for photoalignment, formed using a liquid crystal alignment agent as described in any one of claims 1 to 3.

5. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 3.

6. A liquid crystal display element comprising: a liquid crystal alignment film as described in claim 4 or claim 5.

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