Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal element using same

Abstract

The invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element using the same. The liquid crystal aligning agent contains at least one polymer (K) selected from the group consisting of a polyamic acid, a polyamic acid ester and a polyimide, and the raw material composition of the polymer (K) contains at least one tetracarboxylic acid derivative represented by formula (I) and at least one diamine having a structure represented by formula (II).

Description

Technical Field

[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal elements using the same. Background Technology

[0002] Liquid crystal elements are known to cause optical phenomena such as refraction, scattering, and reflection of electromagnetic waves incident on the element by controlling or modulating the orientation state of the liquid crystal layer within the element. Specifically, in addition to the liquid crystal display elements described below, liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters are also known.

[0003] As liquid crystal display (LCD) elements, various driving methods are known, including TN (Twisted Nematic) mode, STN (SuperTwisted Nematic) mode, IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, and VA (Multi-domain Vertical Alignment) mode with vertical alignment. These LCD elements are used in image display devices of various electronic devices such as televisions and mobile phones, and have been developed with the goal of further improving display quality. Specifically, the performance improvement of LCD elements is achieved not only through improvements in driving methods and element structure, but also through the components used in the elements. Moreover, among the components used in LCD elements, the liquid crystal alignment film is one of the important materials involved in display quality, and research on this liquid crystal alignment film has been actively carried out to meet the requirements of high-quality LCD elements.

[0004] Patent document 1 discloses the use of polyamic acid with a Boc structure (Boc being tert-butoxycarbonyl) to form a liquid crystal alignment film, thereby improving liquid crystal alignment.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent document 1: Japanese Patent Application Publication No. 2023-155156. Summary of the Invention

[0008] In recent years, the applications of liquid crystal display (LCD) elements have expanded to many areas, including monitors for personal computers, LCD televisions, mobile phones, smartphone displays, and medical monitors. Furthermore, there is a growing demand for superior display quality, and image retention is a crucial characteristic affecting display quality. To improve image retention in liquid crystal alignment films, it is necessary to obtain liquid crystal alignment films that exhibit excellent liquid crystal alignment properties.

[0009] In order to further improve the quality of liquid crystal display elements, the inventors conducted research and obtained the following insights: by using a polymer of a diamine having the structure shown in formula (II) instead of the Boc structure, a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be obtained even when either a rubbing treatment or a photo-alignment treatment is used to fabricate the liquid crystal alignment film.

[0010] Therefore, the inventors have conducted in-depth research with the aim of providing a liquid crystal alignment film capable of forming a liquid crystal display element with good image retention characteristics and excellent display quality, and with the aim of providing an alignment liquid crystal alignment agent capable of forming such a liquid crystal alignment film.

[0011] To solve the above problems, the present invention employs the following methods.

[0012] [1] A liquid crystal alignment agent comprising a polymer (K), said polymer (K) being a polymer selected from at least one of the groups consisting of polyamic acid, polyamic acid ester and polyimide.

[0013] The raw material composition of the polymer (K) comprises at least one tetracarboxylic acid derivative of formula (I) and at least one diamine having the structure of formula (II).

[0014]

[0015] In formula (I), *1, *1', *2, and *2' are bonding bonds, each independently bonded to a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms. At least one of the groups *1 and *1' and *2 and *2' can bond to the same oxygen atom.

[0016] R b1 R b2 R b3 and R b4 Each is independently a hydrogen atom or a methyl group, with at least one being a methyl group.

[0017]

[0018] In formula (II), *3 and *4 are bonding bonds, each being a bonding bond between a hydrogen atom and a carbon atom, wherein one or both of *3 and *4 are bonding bonds between carbon atoms.

[0019] A 1 It is a monovalent hydrocarbon group with 5 or more carbon atoms, or a monovalent group with 5 or more carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group.

[0020] [2] According to the liquid crystal alignment agent described in [1], wherein, in the formula (II), A 1 It is a monovalent hydrocarbon group with 5 to 10 carbon atoms, or a monovalent group with 5 to 10 carbon atoms having -O- between carbon bonds of the hydrocarbon group.

[0021] [3] According to [2], the liquid crystal alignment agent further comprises a polymer (L), wherein the polymer (L) is a polymer selected from at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

[0022] The raw material composition of the polymer (L) does not contain diamines having the structure shown in formula (II).

[0023] [4] According to the liquid crystal alignment agent described in [3], wherein the structure shown in formula (II) is the structure shown in formula (III).

[0024]

[0025] In formula (III), *3 and *4 are bonding bonds, each independently a bonding bond between a hydrogen atom and a carbon atom, wherein one or both of *3 and *4 are bonding bonds between carbon atoms.

[0026] R a1 R a2 and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

[0027] [5] According to the liquid crystal alignment agent of [4], wherein the compound represented by formula (I) is the compound represented by formula (I-1).

[0028]

[0029] [6] According to the liquid crystal alignment agent of [5], the diamine having the structure shown in formula (III) includes at least one of the diamines shown in formulas (III-1) to (III-23).

[0030]

[0031]

[0032] In equations (III-1) to (III-23), e is an integer from 2 to 10, and D is the structure shown in equation (V) below.

[0033]

[0034] R a1 R a2 and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

[0035] [7] According to the liquid crystal alignment agent of [5], wherein the diamine having the structure shown in formula (III) includes at least one of the diamines shown in formulas (D-10) to (D-19).

[0036]

[0037] [8] According to the liquid crystal alignment agent of [5], wherein the raw material composition of the polymer (K) comprises at least one of the compounds represented by formula (DI-4-1), (DI-5-1) or (DI-13-1).

[0038]

[0039] In equation (DI-5-1), m is 2 or 4.

[0040] [9] A liquid crystal alignment agent, which is one of the liquid crystal alignment agents described in any one of [1] to [8], and is used for a transverse electric field type liquid crystal display element in a light alignment manner.

[0041]

[10] A liquid crystal alignment film formed from any one of [1] to [9].

[0042]

[11] A liquid crystal element having the liquid crystal alignment film described in

[10] .

[0043]

[12] A method for manufacturing a liquid crystal alignment film includes the following steps:

[0044] The liquid crystal alignment agent described in any one of [1] to [9] is applied to the substrate;

[0045] The substrate is fired; and

[0046] The substrate is irradiated with polarized ultraviolet light.

[0047] By using the liquid crystal alignment agent of the present invention, a liquid crystal alignment film capable of forming a liquid crystal display element with good image retention characteristics and excellent display quality can be obtained. Furthermore, by using this liquid crystal alignment film, the manufacture of a liquid crystal display element with good image retention characteristics and excellent display quality can be effectively achieved. Detailed Implementation

[0048] The present invention will now be described in detail. The descriptions of the constituent elements described below are sometimes based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. The "liquid crystal alignment agent" in the present invention is a liquid crystal alignment agent capable of imparting anisotropy by performing an alignment process after forming the film on a substrate. Furthermore, in the present invention, "tetracarboxylic acid derivative" refers to tetracarboxylic dianhydride, tetracarboxylic acid diester, or tetracarboxylic acid diester dihalide. Sometimes, tetracarboxylic acid diester and tetracarboxylic acid diester dihalide are collectively referred to as derivatives of tetracarboxylic dianhydride. Additionally, in the present invention, diamines and dihydrazides are sometimes referred to as "diamines". * in the chemical formulas of this specification indicates a bonding bond.

[0049] <The Liquid Crystal Alignment Agent for Alignment in this Invention>

[0050] The alignment liquid crystal alignment agent of the present invention is characterized in that it comprises a polymer (K), said polymer (K) being a polymer selected from at least one of the group consisting of polyamic acid, polyamic acid ester and polyimide, wherein the raw material composition of said polymer (K) comprises at least one tetracarboxylic acid derivative of formula (I) and at least one diamine having the structure of formula (II).

[0051] In this invention, polyamic acid derivatives refer to polyimide, some polyimide, polyamic acid ester, polyamic acid-polyamide copolymer, and polyamide-imide.

[0052] <Types of Polymers>

[0053] The following is a detailed description of polyamic acid and polyamic acid derivatives.

[0054] Here, polyamic acid is a polymer synthesized by the polymerization reaction of tetracarboxylic dianhydride (formula (AN)) and diamine (formula (DI)), and has the structural unit shown in formula (PAA). When the polyamic acid-containing liquid crystal alignment agent is heated and sintered during the process of forming a liquid crystal alignment film, the polyamic acid is imidized, enabling the formation of a polyimide liquid crystal alignment film having the structural unit shown in formula (PI).

[0055]

[0056] In equations (AN), (PAA), and (PI), X 1X is a tetravalent organic group. In formulas (DI), (PAA), and (PI), X 2 It is a divalent organic group. Regarding X... 1 For a preferred range and specific examples of the tetravalent organic groups in X, please refer to the corresponding structures of tetracarboxylic dianhydrides described in this specification. 2 For preferred ranges and specific examples of divalent organic groups, please refer to the description of the corresponding structures of diamines or dihydrazides in the diamines section of this specification.

[0057] Polyamic acid derivatives are compounds whose properties are altered by replacing a portion of polyamic acid with other atoms or groups, and substances that improve solubility in solvents used in liquid crystal alignment agents are particularly preferred. Specifically, examples of such polyamic acid derivatives include: 1) polyimides in which all amino and carboxyl groups of polyamic acid have undergone a dehydration ring-closure reaction; 2) partially dehydration ring-closure reactions of polyimides; 3) polyamic acid esters in which the carboxyl groups of polyamic acid are converted to esters; 4) polyamic acid-polyamide copolymers obtained by replacing a portion of the dianhydride contained in a tetracarboxylic acid dianhydride compound with an organic dicarboxylic acid and reacting the reaction; and 5) polyamic acid-polyamide copolymers obtained by undergoing a dehydration ring-closure reaction of a portion or all of the polyamic acid-polyamide copolymer. Among these derivatives, for example, substances having the structural units shown in the above formula (PI) can be cited as polyimides, and substances having the structural units shown in the following formula (PAE) can be cited as polyamic esters.

[0058]

[0059] In formula (PAE), X 1 X is a tetravalent organic group. 2 Y is a divalent organic group, and Y is independently an alkyl group. Regarding X... 1 X 2 For the preferred range and specific examples, please refer to the information about X in formula (PAA). 1 X 2 The description states that Y preferably contains straight-chain or branched alkyl groups having 1 to 6 carbon atoms, and more preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, or tert-butyl.

[0060] The tetracarboxylic dianhydride and diamine used in the synthesis of polyamic acid can be one or more of the same.

[0061] When the polyamic acid of the present invention is used to prepare a polyimide as a polyamic acid derivative, the polyimide can be obtained by subjecting the obtained polyamic acid solution to an anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride as a dehydrating agent, and a tertiary amine such as triethylamine, pyridine, or Collidine as a dehydration ring-closing catalyst, at a temperature of 20–150°C. Alternatively, the polyamic acid can be precipitated from the obtained polyamic acid solution using a large amount of unsuitable solvent (alcohol solvents such as methanol, ethanol, or isopropanol, or ethylene glycol solvents), and the precipitated polyamic acid can be subjected to an imidization reaction in a solvent such as toluene or xylene with the aforementioned dehydrating agent and dehydration ring-closing catalyst at a temperature of 20–150°C, thereby obtaining the polyimide.

[0062] In the imidization reaction, the ratio of dehydrating agent to dehydration ring-closing catalyst is preferably 0.1 to 10 (molar ratio). The total amount of dehydrating agent and dehydration ring-closing catalyst used is preferably 1.5 to 10 times the total molar amount of tetracarboxylic dianhydride used in the synthesis of the polyamic acid. By adjusting the amount of dehydrating agent, catalyst, reaction temperature, and reaction time used in the imidization reaction, the degree of imidization can be controlled, thereby obtaining partially imidized polyimides of only a portion of the polyamic acid. The obtained polyimide can be separated from the solvent used in the reaction and dissolved in another solvent for use as a liquid crystal alignment agent, or it can be used as a liquid crystal alignment agent without separation from the solvent.

[0063] Polyamates can be synthesized by reacting polyamic acid with hydroxyl-containing compounds, halides, epoxy-containing compounds, etc., or by reacting tetracarboxylic acid diesters or tetracarboxylic acid diester dichlorides derived from tetracarboxylic dianhydride with diamines. Tetracarboxylic acid diesters derived from tetracarboxylic dianhydride can be obtained, for example, by reacting tetracarboxylic acid dianhydride with 2 equivalents of an alcohol to open the ring, and tetracarboxylic acid diester dichlorides can be obtained by reacting tetracarboxylic acid diesters with 2 equivalents of a chlorinating agent (e.g., thionyl chloride). Furthermore, polyamates can have only an amide ester structure, or they can be partially esterified products containing both amide acid and amide ester structures.

[0064] The polyamic acid or its derivatives of the present invention can be manufactured in the same manner as known polyamic acids or their derivatives used in the formation of polyimide films. The total amount of tetracarboxylic acid derivatives is preferably 0.9 to 1.1 moles relative to the total amount of diamines per mole.

[0065] The liquid crystal alignment agent of the present invention may contain only one of these polyamic acids, polyamic esters, and polyimides obtained by imidizing them, or it may contain two or more.

[0066] The molecular weight of the polyamic acid or its derivatives of the present invention, expressed as a weight-average molecular weight (Mw) converted from polystyrene, is preferably 5,000 to 500,000, more preferably 5,000 to 50,000. The molecular weight of the polyamic acid or its derivatives can be determined by gel permeation chromatography (GPC).

[0067] The polyamic acid or its derivatives of the present invention can be confirmed by analyzing the solid components obtained by precipitation with a large amount of unsuitable solvent using IR (infrared spectroscopy) or NMR (nuclear magnetic resonance analysis). Furthermore, the monomer used can be identified by analyzing the extracts of the decomposition products of the polyamic acid or its derivatives formed from aqueous solutions of strong bases such as KOH and NaOH using GC (gas chromatography), HPLC (high-performance liquid chromatography), or GC-MS (gas chromatography-mass spectrometry).

[0068] <Tetracarboxylic acid derivatives>

[0069] The polymer (K) of the present invention comprises the compound shown in formula (I) as a raw material, and may also contain other tetracarboxylic acid derivatives. Specific examples of the compound shown in formula (I) and other tetracarboxylic acid derivatives are described below.

[0070] <Compounds represented by formula (I)>

[0071] The compound represented by formula (I) used in the raw materials of the polymer (K) of the present invention will be described.

[0072]

[0073] In formula (I), *1, *1', *2, and *2' are bonding bonds, each independently bonded to a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms. At least one of the groups *1 and *1' and *2 and *2' can be bonded to the same oxygen atom.

[0074] R b1 R b2 R b3 and R b4 Each is independently a hydrogen atom or a methyl group, with at least one being a methyl group.

[0075] Specific examples of alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, or tert-butoxy. From the perspective of ease of imidization, methoxy is preferred.

[0076] Formula (I) includes the following forms: a form in which all four bonds are bonded to any one of a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms; a form in which either *1 and *1' or *2 and *2' is bonded to the same oxygen atom, and the remaining two bonds are bonded to any one of a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms; and a form in which both *1 and *1' and *2 and *2' are bonded to the same oxygen atom. Preferably, the forms in which all four bonds are bonded to any one of a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms, and the forms in which both *1 and *1' and *2 and *2' are bonded to the same oxygen atom are preferred.

[0077] From the viewpoint of obtaining a liquid crystal alignment film with high liquid crystal alignment properties, R is preferred. b1 and R b4 Methyl, R b2 and R b3 It is a hydrogen atom.

[0078] Preferred examples of compounds represented by formula (I) are listed below.

[0079]

[0080] In the polymer (K) of the present invention, a liquid crystal alignment agent that can form a liquid crystal alignment film with high liquid crystal alignment properties through photo-alignment treatment can be obtained by using the compound shown in formula (I). Among the compounds shown in formula (I), the compound shown in formula (I-1) is preferred.

[0081] In the polymer (K) of the present invention, the compound represented by formula (I) preferably accounts for 50 mol% or more of the total amount of tetracarboxylic acid derivatives used, more preferably 80 mol% or more, and even more preferably 100 mol%. Multiple compounds represented by formula (I) may also be used in combination.

[0082] <Tetracarboxylic acid derivatives other than formula (I)>

[0083] Hereinafter, tetracarboxylic acid dianhydrides, as tetracarboxylic acid derivatives other than formula (I), will be described using formulas (AN-1) to (AN-9), (AN-10-1), (AN-10-2), (AN-11), (AN-12), (AN-15), and (AN-16-1) to (AN-16-19). These tetracarboxylic acid dianhydrides can also be derived into tetracarboxylic acid diesters and tetracarboxylic acid diester dichlorides for use as raw materials in polymers.

[0084] [Tetracarboxylic dianhydride represented by formula (AN-1)]

[0085]

[0086] In formula (AN-1), G 10 It is a single bond, an alkylene group with 1 to 12 carbon atoms, a 1,4-phenylene group, a 1,4-cyclohexylene group, or the formula (G10-1). R 11 It can be a hydrogen atom or a methyl group independently.

[0087]

[0088] In equation (G10-1), X is independently a single bond, -O-, -S-, or -NR. 1 -, R 1 The group is an alkyl group with 1 to 4 hydrogen atoms or carbon atoms, where n is an integer from 1 to 5 independently and m is an integer from 1 to 3. A group that does not have a fixed bonding position on any carbon atom of the ring indicates that it can bond to any of the bondable carbon atoms in the ring.

[0089] The following are examples of tetracarboxylic acid dianhydrides represented by formula (AN-1).

[0090]

[0091] In equations (AN-1-2) and (AN-1-5), m is an integer from 1 to 12, each independently.

[0092] [Tetracarboxylic dianhydride represented by formula (AN-2)]

[0093]

[0094] In formula (AN-2), G 11 It is a single bond, an alkylene group with 1 to 12 carbon atoms, a 1,4-phenylene group, or a 1,4-cyclohexylene group. X 11 It is a single bond or -CH2-. G 12 It can be any one of the following trivalent groups independently.

[0095]

[0096] When G 12 When G is >N-, 11 Not for single bonds and -CH2-, X 11 Not a single key.

[0097] The following are examples of tetracarboxylic acid dianhydrides represented by formula (AN-2).

[0098]

[0099] In equation (AN-2-1), m is an integer from 1 to 12.

[0100] [Tetracarboxylic dianhydride represented by formula (AN-3)]

[0101]

[0102] In formula (AN-3), ring A 11 It is a cyclohexane ring or a benzene ring.

[0103] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-3) include compounds represented by formulas (AN-3-2) and (AN-3-2).

[0104]

[0105] [Tetracarboxylic acid dianhydride represented by formula (AN-4)]

[0106]

[0107] In equation (AN-4), G 13 It is a single bond, -(CH2) m -, -O-, -S-, -C(CH3)2-, -SO2-, -CO-, -C(CF3)2-, or divalent groups as shown in the following formula (G13-1), where m is an integer from 1 to 12.

[0108] Ring A 11 Each can be independently a cyclohexane ring or a benzene ring. G 13 Can be used with ring A 11 Bonded at any position.

[0109]

[0110] In equation (G13-1), G 13a and G 13b Each group is a divalent group, independently represented by a single bond, -O-, -CONH-, or -NHCO-. The phenylene group is preferably 1,4-phenylene or 1,3-phenylene.

[0111] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-4) include compounds represented by formulas (AN-4-1) to (AN-4-31).

[0112]

[0113]

[0114] In equation (AN-4-17), m is an integer from 1 to 12.

[0115]

[0116]

[0117] [Tetracarboxylic dianhydride represented by formula (AN-5)]

[0118]

[0119] In equation (AN-5), R 11 Independently, it can be a hydrogen atom or a methyl group. Two Rs 11 R in the benzene ring 11 It bonds to any of the substituted positions on the benzene ring.

[0120] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-5) include compounds represented by formulas (AN-5-1) to (AN-5-3).

[0121]

[0122] [Tetracarboxylic dianhydride represented by formula (AN-6)]

[0123]

[0124] In equation (AN-6), X 11 Independently a single bond or -CH2-. X 12 It can be -CH2-, -CH2CH2-, or -CH=CH-. n is 1 or 2. When n is 2, the two X's are... 12 They can be the same or different.

[0125] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-6) include compounds represented by formulas (AN-6-1) to (AN-6-12).

[0126]

[0127] [Tetracarboxylic dianhydride represented by formula (AN-7)]

[0128]

[0129] In equation (AN-7), X 11 It is a single bond or -CH2-.

[0130] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-7) include compounds represented by formulas (AN-7-1) and (AN-7-2).

[0131]

[0132] [Tetracarboxylic dianhydride represented by formula (AN-8)]

[0133]

[0134] In equation (AN-8), X 11 It is a single bond or -CH2-. R 12 It can be a hydrogen atom, methyl, ethyl, or phenyl group. Ring A 12 It is a cyclohexane ring or a cyclohexene ring.

[0135] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-8) include compounds represented by formulas (AN-8-1) and (AN-8-2).

[0136]

[0137] [Tetracarboxylic dianhydride represented by formula (AN-9)]

[0138]

[0139] In equation (AN-9), r is 0 or 1 independently.

[0140] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-9) include compounds represented by formulas (AN-9-1) to (AN-9-3).

[0141]

[0142] [Tetracarboxylic acid dianhydrides represented by formulas (AN-10-1) and (AN-10-2)]

[0143]

[0144] [Tetracarboxylic dianhydride represented by formula (AN-11)]

[0145]

[0146] In formula (AN-11), ring A 11 It can be a cyclohexane ring or a benzene ring on its own.

[0147] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-11) include compounds represented by formulas (AN-11-1) to (AN-11-3).

[0148]

[0149] [Tetracarboxylic dianhydride represented by formula (AN-12)]

[0150]

[0151] In formula (AN-12), ring A 11 Each can be independently a cyclohexane ring or a benzene ring.

[0152] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-12) include compounds represented by formulas (AN-12-1) to (AN-12-3).

[0153]

[0154] [Tetracarboxylic dianhydride represented by formula (AN-15)]

[0155]

[0156] In equation (AN-15), w is an integer from 1 to 10.

[0157] Examples of tetracarboxylic acid dianhydrides represented by formula (AN-15) include compounds represented by formulas (AN-15-1) to (AN-15-3).

[0158]

[0159] [Tetracarboxylic dianhydrides represented by formulas (AN-16-1) to (AN-16-19)]

[0160] Other than the above-mentioned tetracarboxylic dianhydrides, examples include compounds shown in formulas (AN-16-1) to (AN-16-19).

[0161]

[0162]

[0163] <Diamines>

[0164] The polymer (K) of the present invention comprises at least one diamine having the structure shown in formula (II) as a raw material, and may also contain other diamines. Specific examples of diamines having the structure shown in formula (II) and other diamines are described below.

[0165] <Diamines having the structure shown in formula (II)>

[0166] The diamines having the structure shown in formula (II) used in the raw materials of the polymer (K) of the present invention will be described.

[0167]

[0168] In formula (II), *3 and *4 are bonding bonds, each independently a bonding bond between a hydrogen atom and a carbon atom, wherein one or both of *3 and *4 are bonding bonds between carbon atoms.

[0169] A 1It is a monovalent hydrocarbon group with 5 or more carbon atoms, or a monovalent group with 5 or more carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group, preferably a monovalent hydrocarbon group with 5 to 10 carbon atoms, or a monovalent group with 5 to 10 carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group.

[0170] From the perspective of liquid crystal alignment films with high liquid crystal alignment properties, the structure shown in formula (II) is preferably the structure shown in formula (III).

[0171]

[0172] In formula (III), *3 and *4 are bonding bonds, each independently a bonding bond between a hydrogen atom and a carbon atom, wherein one or both of *3 and *4 are bonding bonds between carbon atoms.

[0173] R a1 R a2 and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

[0174] The following describes specific examples of diamines having the structure shown in formula (III).

[0175]

[0176]

[0177] In formulas (III-1) to (III-23), e is an integer from 2 to 10, D is preferably the structure shown in formula (IV), more preferably the structure shown in formula (V), and even more preferably the structure shown in formulas (VI-1) to (VI-3).

[0178]

[0179] In equation (IV), A 1 It is a monovalent hydrocarbon group with 5 or more carbon atoms, or a monovalent group with 5 or more carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group, preferably a monovalent hydrocarbon group with 5 to 10 carbon atoms, or a monovalent group with 5 to 10 carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group.

[0180]

[0181] R a1 R a2and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

[0182]

[0183] <Other Diamines>

[0184] As raw materials for the polymer (K) of the present invention, specific examples of diamines that can be used in combination with diamines having the structure shown in formula (II) are described below.

[0185]

[0186] In equation (DI-1), G 20 It is an alkylene group or a group represented by formula (DI-1-a) having 1 to 12 carbon atoms. In G 20 When it is an alkylene group having 1 to 12 carbon atoms, at least one of -CH2- can be substituted by -NH- or -O- but they are not adjacent, and at least one hydrogen atom of -CH2- can be substituted by a hydroxyl or methyl group.

[0187]

[0188] In equation (DI-1-a), v is an integer from 1 to 6, which can be used independently.

[0189] In equations (DI-3), (DI-6), and (DI-7), G 21 Independently, it can be a single bond, -NH-, -NCH3-, -O-, -S-, -SS-, -SO2-, -CO-, -COO-, -CONCH3-, -CONH-, -C(CH3)2-, -C(CF3)2-, or -(CH2). m -、-O-(CH2) m -O-、-N(CH3)-(CH2) k -N(CH3)-、-(O-C2H4) m -O-, -O-CH2-C(CF3)2-CH2-O-, -O-CO-(CH2) m -CO-O-, -CO-O-(CH2) m -O-CO-、-(CH2) m -NH-(CH2) m -、-CO-(CH2) k -NH-(CH2) k-、-(NH-(CH2) m ) k -NH-, -CO-C3H6-(NH-C3H6) n -CO- or -S-(CH2)mS-, where m is an integer from 1 to 12, k is an integer from 1 to 5, and n is 1 or 2.

[0190] In equation (DI-4), s is an integer from 0 to 2.

[0191] In equation (DI-5), G 33 For single bonds, -NH-, -NCH3-, -O-, -S-, -SS-, -SO2-, -CO-, -COO-, -CONCH3-, -CONH-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -、-O-(CH2) m -O-、-(O-C2H4) m -O-, -O-CH2-C(CF3)2-CH2-O-, -O-CO-(CH2) m -CO-O-, -CO-O-(CH2) m -O-CO-、-(CH2) m -NH-(CH2) m -、-CO-(CH2) k -NH-(CH2) k -、-CO-C3H6-(NH-C3H6) n -CO- or -S-(CH2) m -S-、-N(Boc)-(CH2) e -、-(CH2) m -N(Boc)-CONH-(CH2) m -、-(CH2) m -N(Boc)-(CH2) m - or the group represented by the following formula (DI-5-a) or the following formula (DI-5-b), where m is independently an integer from 1 to 12, k is an integer from 1 to 5, e is an integer from 2 to 10, and n is 1 or 2. Boc is tert-butoxycarbonyl.

[0192]

[0193] In equation (DI-5-a), q is an independent integer from 0 to 6. R 44 It can be a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0194] In equations (DI-6) and (DI-7), G22 It can be independently a single bond, -O-, -S-, -CO-, -C(CH3)2-, -C(CF3)2-, or an alkylene group having 1 to 10 carbon atoms.

[0195] In formulas (DI-2) to (DI-7), at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted with a fluorine atom, a chlorine atom, an alkyl group having 1 to 3 carbon atoms, a methoxy group, a hydroxyl group, a trifluoromethyl group, a carboxyl group, a carbamoyl group, a phenylamino group, a phenyl group, or a benzyl group. Furthermore, in formula (DI-4), at least one hydrogen atom of the cyclohexane ring and the benzene ring may be substituted with one of the groups selected from any one of the groups shown in formulas (DI-4-a) to (DI-4-i). In formula (DI-5), in G… 33 When it is a single bond, at least one hydrogen atom of the benzene ring can be replaced by NHBoc or N(Boc)2.

[0196]

[0197] In equations (DI-4-a) and (DI-4-b), R 20 It can be a hydrogen atom or a methyl group independently. In formulas (DI-4-f) and (DI-4-g), m can be an integer from 0 to 12 independently, and Boc is a tert-butoxycarbonyl group.

[0198] In formulas (DI-2) to (DI-7), groups on the carbon atoms constituting the ring without fixed bonding positions indicate that the bonding positions of the ring are arbitrary.

[0199]

[0200] In formula (DI-11), r is 0 or 1. In formulas (DI-8) to (DI-11), the amino groups bonded to the ring are at arbitrary positions.

[0201]

[0202] In formula (DI-12), R 21 and R 22 Each is independently an alkyl or phenyl group having 1 to 3 carbon atoms, G 23 Independently, it is an alkylene, phenylene, or alkyl-substituted phenylene with 1 to 6 carbon atoms, where w is an integer from 1 to 10.

[0203] In formula (DI-13), R 23 Each of the following is independently an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a chlorine atom, and each of p and q is independently an integer from 0 to 4.

[0204] In formula (DI-14), ring B is a monocyclic heterocyclic aromatic group, and R24 It can be a hydrogen atom, fluorine atom, chlorine atom, or an alkyl, alkoxy, alkenyl, or alkynyl group having 1 to 6 carbon atoms, where q is an independent integer from 0 to 4. When q is 2 or more, multiple R groups... 24 They can be the same or different. In formula (DI-15), ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In formula (DI-16), G... 24 It is a single bond, an alkylene group or a 1,4-phenylene group with 2 to 6 carbon atoms, and r is 0 or 1.

[0205] In formula (DI-17), R 23 Independently, it is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a chlorine atom, -NHBoc or -N(Boc)2, p is an integer from 0 to 4, and R 25 It is an alkyl or tert-butoxycarbonyl group consisting independently of a hydrogen atom and having 1 to 4 carbon atoms, where Z is a divalent group containing an alkylene group having 1 to 10 carbon atoms. Any position and any number of -CH2- groups in the alkylene group having 1 to 10 carbon atoms can be replaced by -NH- or -CO-, but -NH- or -CO- are not adjacent.

[0206] R 25 Preferred examples are methyl or Boc, more preferably Boc. A preferred example of the divalent group containing an alkylene group having 1 to 10 carbon atoms in Z is -(CH2). m -, -CO-(CH2)4-CO-, where m is an integer from 1 to 10. The preferred option is -(CH2). m -, further preferred are -(CH2)2-, -(CH2)4-, and -(CH2)6-.

[0207] In formulas (DI-13) to (DI-17), groups on the carbon atoms constituting the ring without fixed bonding positions indicate that the bonding positions of the ring are arbitrary. The bonding positions of the amino groups at both ends of the ring can be arbitrary, preferably para and meta, and more preferably para.

[0208]

[0209] In formula (DIH-1), G 25 It is a single bond, an alkylene group with 1 to 20 carbon atoms, and is -CO-, -O-, -S-, -SO2-, -C(CH3)2- or -C(CF3)2-.

[0210] In formula (DIH-2), ring D is cyclohexylene, phenylene, or naphthylene, and at least one hydrogen atom of this group may be substituted with methyl, ethyl, or phenyl.

[0211] In formula (DIH-3), each ring E is independently cyclohexylene or phenylene, and at least one hydrogen atom of this group can be substituted with methyl, ethyl, or phenyl. The two rings E can be the same or different. Y is a single bond, an alkylene group with 1 to 20 carbon atoms, and is -CO-, -O-, -S-, -SO2-, -C(CH3)2-, or -C(CF3)2-. In formulas (DIH-2) and (DIH-3), the bonding position of the -hydrazide group on the ring is arbitrary.

[0212] Examples of diamines represented by formula (DI-1) are shown in the following formulas (DI-1-1) to (DI-1-9).

[0213]

[0214] In equations (DI-1-7) and (DI-1-8), k is an independent integer from 1 to 3. In equation (DI-1-9), v is an independent integer from 1 to 6.

[0215] Examples of diamines represented by formulas (DI-2) to (DI-3) are shown in the following formulas (DI-2-1), (DI-2-2), (DI-3-1) to (DI-3-3).

[0216]

[0217] Examples of diamines represented by formula (DI-4) are shown in the following formulas (DI-4-1) to (DI-4-27).

[0218]

[0219]

[0220] In equations (DI-4-20) and (DI-4-21), m is an integer from 1 to 12, each independently.

[0221] The preferred raw material composition for the polymer (K) is of formula (DI-4-1).

[0222]

[0223] The following shows an example of a diamine represented by formula (DI-5).

[0224]

[0225] In formula (DI-5-1), m is an integer from 1 to 12. Preferably, the compound in formula (DI-5-1) with m being 2 or 4 is used as the raw material composition for the polymer (K).

[0226]

[0227] In equations (DI-5-12) and (DI-5-13), m is an integer from 1 to 12, each independently.

[0228]

[0229] In equation (DI-5-16), v is an integer from 1 to 6.

[0230]

[0231]

[0232] In equations (DI-5-35) to (DI-5-37), m is an integer from 1 to 12. In equation (DI-5-38), k is an integer from 1 to 5. In equation (DI-5-40), n is an integer of 1 or 2.

[0233]

[0234] In equation (DI-5-44), e is an integer from 2 to 10, and in equation (DI-5-45), R 43 It is a hydrogen atom, (tert-butoxycarbonyl)amino or bis(tert-butoxycarbonyl)amino.

[0235]

[0236]

[0237] Examples of diamines represented by formula (DI-6) are shown in formulas (DI-6-1) to (DI-6-7) below.

[0238]

[0239] Examples of diamines represented by formula (DI-7) are shown in the following formulas (DI-7-1) to (DI-7-11).

[0240]

[0241] In equations (DI-7-3) and (DI-7-4), m is an integer from 1 to 12, and n is 1 or 2.

[0242]

[0243] Examples of diamines represented by formula (DI-8) are shown in the following formulas (DI-8-1) to (DI-8-4).

[0244]

[0245] Examples of diamines represented by formula (DI-9) are shown in formulas (DI-9-1) to (DI-9-3) below.

[0246]

[0247] Examples of diamines represented by formula (DI-10) are shown in the following formulas (DI-10-1) and (DI-10-2).

[0248]

[0249] Examples of diamines represented by formula (DI-11) are shown in the following formulas (DI-11-1) to (DI-11-3).

[0250]

[0251] Examples of diamines represented by formula (DI-12) are shown in the following formula (DI-12-1).

[0252]

[0253] Examples of diamines represented by formula (DI-13) are shown in the following formulas (DI-13-1) to (DI-13-13).

[0254]

[0255] The preferred raw material composition for the polymer (K) is of formula (DI-13-1).

[0256] Examples of diamines represented by formula (DI-14) are shown in the following formulas (DI-14-1) to (DI-14-9).

[0257]

[0258] Examples of diamines represented by formula (DI-15) are shown in the following formulas (DI-15-1) to (DI-5-12).

[0259]

[0260] Examples of diamines represented by formula (DI-16) are shown in the following formula (DI-16-1).

[0261]

[0262] (DI-16-1)

[0263] The following shows an example of a diamine represented by formula (DI-17).

[0264]

[0265] In formulas (DI-17-1) and (DI-17-5), k is an integer from 1 to 6. In formulas (DI-17-2) to (DI-17-3), e is an integer from 1 to 10, and Boc is tert-butoxycarbonyl. In formula (DI-17-4), m is 1 or 2, and n is 1 or 2.

[0266] Examples of compounds represented by any of formulas (DIH-1) to (DIH-3) are shown in the following formulas (DIH-1-1), (DIH-1-2), (DIH-2-1) to (DIH-2-3), and (DIH-3-1) to (DIH-3-6).

[0267]

[0268] In equation (DIH-1-2), m is an integer from 1 to 12.

[0269]

[0270] In the polymer (K) of the present invention, the image retention properties can be improved by using diamines having the structure shown in formula (II). In the polymer (K) of the present invention, the total amount of diamines having the structure shown in formula (II) is preferably 10 mol% or more of the total amount of diamines used. Multiple diamines having the structure shown in formula (II) may also be used in combination.

[0271] In the polymer (L) of the present invention, the image retention properties can be improved by not using diamines having the structure shown in formula (II).

[0272] In the raw material composition used as the raw material for the polymer of the present invention, a portion of the diamine may be substituted with at least one selected from the group consisting of monoamines and monohydrazides. The substitution ratio is preferably in the range of 40 mol% or less of at least one selected from the group consisting of monoamines and monohydrazides relative to the diamine. Such substitution can terminate the polymerization reaction during the formation of polyamic acid and inhibit further polymerization. Therefore, through such substitution, the molecular weight of the resulting polymer (polyamic acid or its derivatives) can be easily controlled, for example, improving the coating properties of the liquid crystal alignment agent without impairing the effects of the present invention. The diamine that can be substituted with monoamines or monohydrazides may be one or more, provided that the effects of the present invention are not impaired. Examples of such monoamines include aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecanylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, p-aminophenyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

[0273] When the polymer of the present invention is polyamic acid or a derivative thereof, the raw material composition may further include a monoisocyanate compound as a monomer. By including a monoisocyanate compound in the monomer, the ends of the obtained polyamic acid or derivative thereof are modified, and the molecular weight is adjusted. By using the end-modified polyamic acid or derivative thereof, for example, the coating properties of the liquid crystal alignment agent can be improved without impairing the effects of the present invention. From the above viewpoint, the content of the monoisocyanate compound in the monomer is preferably 1 to 10 mol% relative to the total amount of diamine and tetracarboxylic dianhydride in the monomer. Examples of monoisocyanate compounds include phenyl isocyanate and naphthyl isocyanate.

[0274] The liquid crystal alignment agent of the present invention can be composed of the polymer (K) and polymer (L) of the present invention, or it can be a mixture of the polymer of the present invention and polymers other than the polymer of the present invention. Furthermore, in this specification, a liquid crystal alignment agent that mixes two or more of the described polymers is sometimes referred to as a mixed-type liquid crystal alignment agent.

[0275] Furthermore, from the viewpoint of the coatability of the liquid crystal alignment agent and the adjustment of the concentration of the polyamic acid or its derivatives, the liquid crystal alignment agent of the present invention may further contain a solvent. The solvent can be any solvent capable of dissolving polymeric components without particular limitation. The solvent broadly includes solvents commonly used in the manufacturing processes and applications of polymeric components such as polyamic acid and soluble polyimide, and can be appropriately selected according to the intended use. The solvent may be one type or a mixture of two or more solvents.

[0276] Examples of solvents include the master solvent of the polyamic acid or its derivatives, and other solvents intended to improve coatability.

[0277] Examples of aprotic polar organic solvents that are solubilizing with respect to polyamic acid or its derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylimidazolium ketone, N-methylcaprolactam, N-methylpropionamide, N,N-dimethylacetamide, dimethyl sulfoxide, N,N-dimethylformamide, N,N-diethylformamide, diethylacetamide, N,N-dimethylisobutylamide, γ-butyrolactone, and γ-valerolactone. Among these, N-methyl-2-pyrrolidone, dimethylimidazolium ketone, γ-butyrolactone, or γ-valerolactone are preferred.

[0278] Examples of other solvents used to improve coatability include ethylene glycol monobutyl ether, ethylene glycol monotert-butyl ether and other ethylene glycol monoalkyl ethers, diethylene glycol monoethyl ether and other diethylene glycol monoalkyl ethers, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether and other diethylene glycol dialkyl ethers. Additionally, examples include propylene glycol monomethyl ether, 1-butoxy-2-propanol and other propylene glycol monoalkyl ethers, dipropylene glycol monomethyl ether and other dipropylene glycol monoalkyl ethers, triethylene glycol monoalkyl ethers, butyl cellosolve acetate, phenyl acetate, and ester compounds of these acetates. Examples also include dialkyl malonates such as diethyl malonate, alkyl lactates, diisobutyl ketone, diacetone alcohol, 3-methyl-3-methoxybutanol, 4-methyl-2-pentanol, diisobutylmethanol, tetrahydronaphthalene, and isophorone.

[0279] Among them, preferred ingredients include diisobutyl ketone, 4-methyl-2-pentanol, diisobutylmethanol, ethylene glycol monobutyl ether, ethylene glycol monotert-butyl ether, diethylene glycol monoethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, 1-butoxy-2-propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, or butyl cellosolve acetate.

[0280] The concentration of the solid component in the liquid crystal alignment agent of the present invention is not particularly limited, and the optimal value can be selected according to the various coating methods described below. Generally, in order to suppress unevenness, pinholes, etc. during coating, the concentration is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, relative to the weight of the varnish.

[0281] The viscosity of the liquid crystal alignment agent of the present invention varies depending on the coating method, the concentration of the polyamic acid or its derivative, the type of polyamic acid or its derivative used, and the type and proportion of the solvent. For example, when coating using a printing press, the viscosity is 5 to 100 mPa·s (more preferably 10 to 80 mPa·s). If the viscosity is 5 mPa·s or higher, it is easy to obtain a sufficient film thickness, and if it is 100 mPa·s or lower, it is easy to suppress printing unevenness. When coating using spin coating, a viscosity of 5 to 200 mPa·s (more preferably 10 to 100 mPa·s) is suitable. When coating using an inkjet coating apparatus, a viscosity of 5 to 50 mPa·s (more preferably 5 to 20 mPa·s) is suitable. The viscosity of the liquid crystal alignment agent is measured by rotational viscosity measurement, for example using a rotational viscometer (TVE-20L type viscometer manufactured by Toki Sangyo Co., Ltd.) (measurement temperature: 25°C).

[0282] The liquid crystal alignment agent of the present invention may further contain various additives. Various additives can be selected and used according to their respective purposes to improve the various properties of the liquid crystal alignment film. Examples are shown below.

[0283] <Alkenyl-substituted nadicimide compounds>

[0284] For example, for the purpose of stabilizing the electrical properties of the liquid crystal display element over a long period, the liquid crystal alignment agent of the present invention may further contain an alkenyl-substituted nadicimide compound. One alkenyl-substituted nadicimide compound may be used, or two or more may be used in combination. For the above-mentioned purpose, the content of the alkenyl-substituted nadicimide compound relative to polyamic acid or its derivatives is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 20% by weight. The alkenyl-substituted nadicimide compound is preferably a compound that can be dissolved in a solvent in which the polyamic acid or its derivatives used in the present invention are dissolved. Examples of preferred alkenyl-substituted nadicimide compounds include those disclosed in Japanese Patent Application Publication Nos. 2008-096979, 2009-109987, and 2013-242526. Examples of particularly preferred alkenyl-substituted nadicimide compounds include bis{4-(allylbicyclo[2.2.1]hept-5-en-2,3-dicarboxyimide)phenyl}methane, N,N'-m-xylyl-bis(allylbicyclo[2.2.1]hept-5-en-2,3-dicarboxyimide) or N,N'-hexamethylene-bis(allylbicyclo[2.2.1]hept-5-en-2,3-dicarboxyimide).

[0285] <Compounds with unsaturated double bonds that exhibit free radical polymerization>

[0286] For example, from the perspective of ensuring long-term stability of the electrical properties of liquid crystal display elements, the liquid crystal alignment agent of the present invention may further contain a compound having a radical polymerizable unsaturated double bond. The compound having a radical polymerizable unsaturated double bond may be one compound or two or more compounds. Furthermore, the compound having a radical polymerizable unsaturated double bond does not contain an alkenyl-substituted nadicimide compound. Preferred compounds having free radical polymerizable unsaturated double bonds include N,N'-methylenebisacrylamide, N,N'-dihydroxyethylene-bisacrylamide, ethylene diacrylate, 4,4'-methylenebis(N,N-dihydroxyethylene acrylate aniline), triallyl cyanurate, and compounds having free radical polymerizable unsaturated double bonds disclosed in Japanese Patent Application Publication Nos. 2009-109987, 2013-242526, International Publication No. 2014 / 119682, and International Publication No. 2015 / 152014. For the above-mentioned purposes, the content of the compound having free radical polymerizable unsaturated double bonds is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, relative to polyamic acid or its derivatives.

[0287] <Oxazine compounds>

[0288] For example, for the purpose of stabilizing the electrical properties of the liquid crystal display element over a long period of time, the liquid crystal alignment agent of the present invention may further contain an oxazine compound. The oxazine compound may be one compound or two or more compounds. For the above-mentioned purpose, the content of the oxazine compound relative to polyamic acid or its derivatives is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight.

[0289] Oxazine compounds are soluble in solvents that dissolve polyamic acid or its derivatives. Furthermore, oxazine compounds with ring-opening polymerization properties are preferred. Examples of preferred oxazine compounds include those shown in formulas (OX-3-1), (OX-3-9), and (OX-3-10), as well as those disclosed in Japanese Patent Application Publication Nos. 2007-286597 and 2013-242526.

[0290]

[0291] <Oxazolin compounds>

[0292] For example, from the purpose of stabilizing the electrical properties of the liquid crystal display element over a long period, the liquid crystal alignment agent of the present invention may further contain an oxazoline compound. An oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one compound or two or more compounds. For the above-mentioned purpose, the content of the oxazoline compound relative to polyamic acid or its derivatives is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight. Examples of preferred oxazoline compounds include those disclosed in Japanese Patent Application Publication No. 2010-054872 and Japanese Patent Application Publication No. 2013-242526. 1,3-bis(4,5-dihydro-2-oxazolyl)benzene is even more preferred.

[0293] <Epoxy Compounds>

[0294] For example, for the purpose of stabilizing the electrical properties of the liquid crystal display element over a long period, improving the hardness of the film, or improving adhesion with the sealant, the liquid crystal alignment agent of the present invention may further contain an epoxy compound. The epoxy compound may be one compound or two or more compounds. For the purposes described above, the content of the epoxy compound relative to polyamic acid or its derivatives is preferably 0.1 to 50% by weight, more preferably 1 to 20% by weight, and even more preferably 1 to 10% by weight.

[0295] As an epoxy compound, various compounds having one or more epoxy rings within the molecule can be used.

[0296] For the purpose of improving the hardness of the film or improving the adhesion with the sealant, compounds having two or more epoxy rings in the molecule are preferred, and compounds having three or four epoxy rings are more preferred.

[0297] Examples of epoxy compounds include those disclosed in Japanese Patent Application Publication No. 2009-175715, Japanese Patent Application Publication No. 2013-242526, Japanese Patent Application Publication No. 2016-170409, and International Publication No. 2017 / 217413. Preferred epoxy compounds include N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-epoxypropoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3,3',4,4'-diepoxy)biscyclohexyl, 1,4-butanediol glycidyl ether, tris(2,3-epoxypropyl) isocyanurate, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, or N,N,N',N'-tetraglycidyl-m-xylenediamine. More preferred compounds include 3-epoxypropoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. In addition to the above, oligomers or polymers containing epoxy rings can also be added. The oligomers or polymers containing epoxy rings may be those disclosed in Japanese Patent Application Publication No. 2013-242526.

[0298] <Silane compounds>

[0299] For example, to improve adhesion to the substrate and sealant, the liquid crystal alignment agent of the present invention may further contain a silane compound. For the purposes described above, the content of the silane compound relative to polyamic acid or its derivatives is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, and even more preferably 0.5 to 10% by weight.

[0300] As silane compounds, silane coupling agents disclosed in Japanese Patent Application Publication No. 2013-242526, Japanese Patent Application Publication No. 2015-212807, Japanese Patent Application Publication No. 2018-173545, and International Publication No. 2018 / 181566 can be used. Preferred silane coupling agents include 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, p-aminophenyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-isocyanate-propyltriethoxysilane, or 3-ureidopropyltriethoxysilane.

[0301] In addition to the additives described above, compounds having cyclic carbonate groups, hydroxyalkylamide sites, or hydroxyl groups may be added to improve the strength of the liquid crystal alignment film or to ensure long-term stability of the electrical properties of the liquid crystal display element. Examples of specific compounds include those disclosed in Japanese Patent Application Publication No. 2016-118753 and International Patent Publication No. 2017 / 110976. Preferred compounds include those with formulas (HD-1) to (HD-4). These compounds are preferably present in amounts of 0.5 to 50% by weight, more preferably 1 to 30% by weight, and even more preferably 1 to 10% by weight relative to polyamic acid or its derivatives.

[0302]

[0303] Furthermore, when improved antistatic properties are required, antistatic agents can be used, and when imidization is performed at low temperatures, imidization catalysts can be used. As an imidization catalyst, the imidization catalyst disclosed in Japanese Patent Application Publication No. 2013-242526 can be cited as an example.

[0304] Liquid crystal alignment film

[0305] The liquid crystal alignment film of the present invention is formed by heating a coating of the liquid crystal alignment agent described above. The liquid crystal alignment film of the present invention can be obtained by conventional methods for producing liquid crystal alignment films using liquid crystal alignment agents. For example, the liquid crystal alignment film of the present invention can be obtained by a process of forming a coating of the liquid crystal alignment agent of the present invention, a process of heating and drying, and a process of heating and firing. For the liquid crystal alignment film of the present invention, an anisotropic treatment is performed. As a treatment, anisotropy can also be imparted by friction treatment, but it is preferable to impart anisotropy by light irradiation.

[0306] The method for forming the liquid crystal alignment film of the liquid crystal alignment agent of the present invention will be described below.

[0307] The coating can be formed in the same way as the conventional liquid crystal alignment film by coating the liquid crystal alignment agent of the present invention onto the substrate in the liquid crystal display element. Examples of substrates include those made of glass, silicon nitride, acrylic, polycarbonate, and polyimide, which can be provided with electrodes such as ITO (Indium Tin Oxide), IZO (In₂O₃-ZnO), and IGZO (In-Ga-ZnO₄), color filters, etc.

[0308] Commonly known methods for applying liquid crystal alignment agents to a substrate include spin coating, printing, dipping, drop casting, and inkjet printing. These methods are also applicable in this invention.

[0309] The heating and drying process is generally known to involve methods such as heating in an oven or infrared furnace, or heating on a heating plate. The heating and drying process is preferably carried out at a temperature within the range where the solvent can evaporate, and more preferably at a temperature lower than that in the heating and firing process. Specifically, the heating and drying temperature is preferably in the range of 30°C to 150°C, and more preferably in the range of 50°C to 120°C.

[0310] The heating and firing process can be carried out under conditions required for the imidization reaction of polyamic acid or its derivatives. Methods for firing coatings, such as heating in an oven or infrared furnace, or heating on a hot plate, are generally known. These methods are also applicable to this invention. It is generally preferred to carry out the process at a temperature of around 90–300°C, more preferably 120–280°C, and even more preferably 150–250°C. The firing time is not particularly limited, but is generally between 1 minute and 2 hours, and typically between 10 minutes and 40 minutes.

[0311] Heating can be done in multiple stages, or the temperature can be changed during this process.

[0312] To align the liquid crystal in one direction relative to the horizontal and / or vertical directions, a known optical alignment method can be preferably used as a means of imparting anisotropy to the liquid crystal alignment film.

[0313] The light used in the photo-alignment process can be, for example, ultraviolet or visible light with wavelengths of 150–800 nm. There are no particular limitations on the type of light, as long as it can impart liquid crystal alignment capability to the thin film. However, when it is desired that the liquid crystal exhibit strong alignment constraint, polarized light is preferred, and linearly polarized light is even more preferred.

[0314] The wavelength of the polarized light in the above-mentioned light irradiation process is preferably 150–400 nm, more preferably 200–400 nm, and even more preferably 200–300 nm. The irradiation dose of the polarized light is preferably 0.001–10 J / cm. 2 More preferably 0.1–5 J / cm 2 There is no particular limitation on the irradiation angle of the polarized light film surface. However, from the viewpoint of shortening the alignment processing time, it is preferable to irradiate the film surface as perpendicularly as possible to exhibit a strong alignment constraint force on the liquid crystal. Furthermore, by irradiating linearly polarized light, the liquid crystal alignment film of the present invention can align the liquid crystal in a direction perpendicular to the polarization direction of the linearly polarized light.

[0315] The light source used in the irradiation process can be any type of lamp without restriction, including ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, deep ultraviolet (Deep UV) lamps, halogen lamps, metal halide lamps, high-power metal halide lamps, xenon lamps, mercury xenon lamps, excimer lamps, KrF (krypton fluoride) excimer lasers, fluorescent lamps, LED (Light Emitting Diode) lamps, sodium lamps, microwave-excited electrodeless lamps, etc.

[0316] To improve the liquid crystal alignment capability of the liquid crystal alignment film, it can be heated while being irradiated with light. In this case, the heating temperature is preferably in the range of 50°C to 250°C.

[0317] The light irradiation process can be performed after the heating and drying process or after the heating and firing process, preferably after the heating and firing process. Alternatively, it can be performed simultaneously with the heating and drying process.

[0318] The liquid crystal alignment film of the present invention is preferably subjected to additional heating after the light irradiation process. The heating temperature is the same as or higher than the temperature of the heating and firing process, preferably 150-300°C, more preferably 150-250°C, and even more preferably 200-250°C. The additional heating time is preferably 5 minutes to 2 hours, more preferably 5-60 minutes, and even more preferably 5-30 minutes.

[0319] Alternatively, a washing process can be performed after the light irradiation process or after an additional heating process. Specifically, the liquid crystal alignment film is immersed in a solvent. The immersion temperature is preferably 10–80°C, more preferably 20–50°C. Ultrasonic treatment is also preferred. The treatment time is preferably 1 minute to 1 hour, more preferably 1 minute to 30 minutes. The solvent used is not particularly limited; it can be any solvent that dissolves the decomposition products generated by the liquid crystal alignment film under ultraviolet irradiation. Examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. From the viewpoint of versatility and safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred. After immersion, heating or rinsing is preferred. Alternatively, both methods can be used. The heating temperature is preferably 150–300°C, more preferably 200–230°C. The heating time is preferably 10 seconds–30 minutes, more preferably 1–10 minutes. The solvent used for rinsing is preferably a low-boiling-point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone.

[0320] The thickness of the liquid crystal alignment film of the present invention is not particularly limited, but is preferably 10-300 nm, more preferably 30-150 nm. The thickness of the liquid crystal alignment film of the present invention can be measured by known film thickness measuring devices such as a step difference meter and an ellipsometer.

[0321] The liquid crystal alignment film of the present invention is suitable for alignment control of liquid crystal compositions in liquid crystal display elements. Besides its application in the alignment of liquid crystal compositions in liquid crystal display elements, it can also be used for alignment control of liquid crystal materials in all other liquid crystal elements such as liquid crystal antennas, dimming windows, optical compensation materials, and variable phase shifters.

[0322] Liquid crystal display element

[0323] Next, the liquid crystal display element of the present invention will be described. The liquid crystal display element of the present invention is characterized by having the liquid crystal alignment film of the present invention, enabling it to achieve high display quality with suppression of bright spots caused by light decomposition products and good image retention characteristics.

[0324] The liquid crystal display element of the present invention will be described in detail. In the liquid crystal display element of the present invention, which has a pair of opposing substrates, electrodes formed on one or both of the opposing surfaces of each of the pair of substrates, a liquid crystal alignment film formed on the opposing surfaces of each of the pair of substrates, a liquid crystal layer formed between the pair of substrates, a pair of polarizing films disposed such that they sandwich the opposing substrates, a backlight, and a driving device, the liquid crystal alignment film is composed of the liquid crystal alignment film of the present invention.

[0325] There is no particular limitation as long as the electrode is formed on one side of the substrate. Examples of such electrodes include ITO and vapor-deposited metal films. Furthermore, the electrode can be formed on the entire surface of one side of the substrate, or it can be formed into a desired shape, such as a patterned shape. Desired electrode shapes include comb-shaped or serrated structures. The electrode can be formed on one of a pair of substrates, or it can be formed on both substrates. The method of electrode formation varies depending on the type of liquid crystal display element. For example, in the case of IPS-type liquid crystal display elements and FFS-type liquid crystal display elements (lateral electric field type liquid crystal display elements), the electrode is disposed on one side of the pair of substrates; in the case of other liquid crystal display elements, the electrode is disposed on both sides of the pair of substrates. The liquid crystal alignment film is formed on the substrate or the electrode.

[0326] The liquid crystal layer is formed by sandwiching a liquid crystal composition between a pair of substrates with opposite surfaces on which liquid crystal alignment films are formed. During the formation of the liquid crystal layer, spacers such as microparticles or resin sheets can be used to form appropriate intervals between the pair of substrates, as needed.

[0327] As methods for forming liquid crystal layers, vacuum injection and ODF (One Drop Fill) methods are known.

[0328] In the vacuum injection method, gaps (cell gaps) are set with the liquid crystal alignment film surfaces facing each other, leaving an injection port for the liquid crystal. A sealant is then printed, and the substrate is bonded. Liquid crystal is injected into the cell gaps defined by the substrate surface and the sealant using a vacuum differential pressure. The injection port is then sealed to manufacture a liquid crystal display element.

[0329] In the ODF method, a sealant is printed on the outer periphery of one liquid crystal alignment film surface of a pair of substrates. Liquid crystal is then dropped onto the area inside the sealant, and the other substrate is bonded with the liquid crystal alignment film surfaces facing each other. The liquid crystal is then spread across the entire surface of the substrate, and the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, thus manufacturing a liquid crystal display element.

[0330] In addition to UV (Ultraviolet) curable sealants, thermosetting sealants are also known for use in bonding substrates. Sealants can be printed, for example, using screen printing.

[0331] There are no particular limitations on the liquid crystal composition; various liquid crystal compositions with positive or negative dielectric anisotropy can be used. Among the preferred liquid crystal compositions with positive dielectric anisotropy are Japanese Patent No. 3086228, Japanese Patent No. 2635435, Japanese Patent No. 5-501735, Japanese Patent No. 8-157826, Japanese Patent No. 8-231960, Japanese Patent No. 9-241644 (EP885272A1), Japanese Patent No. 9-302346 (EP806466A2), and Japanese Patent No. 8-199168 (EP72). Liquid crystal compositions disclosed in Japanese Patent Application Publication No. 2998A1, Japanese Patent Application Publication No. 9-235552, Japanese Patent Application Publication No. 9-255956, Japanese Patent Application Publication No. 9-241643 (EP885271A1), Japanese Patent Application Publication No. 10-204016 (EP844229A1), Japanese Patent Application Publication No. 10-204436, Japanese Patent Application Publication No. 10-231482, Japanese Patent Application Publication No. 2000-087040, and Japanese Patent Application Publication No. 2001-48822.

[0332] Preferred examples of the liquid crystal compositions exhibiting negative dielectric constant anisotropy include Japanese Patent Publication Nos. 57-114532, 2-4725, 4-224885, 8-40953, 8-104869, 10-168076, 10-168453, and 10-236989. Japanese Patent Publication No. 10-236990, Japanese Patent Publication No. 10-236992, Japanese Patent Publication No. 10-236993, Japanese Patent Publication No. 10-236994, Japanese Patent Publication No. 10-237000, Japanese Patent Publication No. 10-237004, Japanese Patent Publication No. 10-237024, Japanese Patent Publication No. 10-237035, Japanese Patent Publication No. 10-237075, etc. Japanese Patent Publication No. 10-237076, Japanese Patent Publication No. 10-237448 (EP967261A1), Japanese Patent Publication No. 10-287874, Japanese Patent Publication No. 10-287875, Japanese Patent Publication No. 10-291945, Japanese Patent Publication No. 11-029581, Japanese Patent Publication No. 11-080049, Japanese Patent Publication No. 2000-256307, Japanese Patent Publication No. 2001 Liquid crystal compositions disclosed in Japanese Patent Application Publication No. -019965, Japanese Patent Application Publication No. 2001-072626, Japanese Patent Application Publication No. 2001-192657, Japanese Patent Application Publication No. 2010-037428, International Publication No. 2011 / 024666, International Publication No. 2010 / 072370, Japanese Patent Application Publication No. 2010-537010, Japanese Patent Application Publication No. 2012-077201, and Japanese Patent Application Publication No. 2009-084362.

[0333] It can also be used by adding one or more optically active compounds to liquid crystal compositions with positive or negative dielectric anisotropy.

[0334] Furthermore, from the viewpoint of improving orientation, for example, the liquid crystal composition used in the liquid crystal display element of the present invention can be further supplemented with additives. Such additives include photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, polymerization inhibitors, etc. Preferred photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, defoamers, polymerization initiators, and polymerization inhibitors include compounds disclosed in International Publication No. 2015 / 146330, etc.

[0335] To suit liquid crystal display elements in PSA (polymer sustained alignment) mode, polymerizable compounds can be incorporated into the liquid crystal composition. Preferred examples of polymerizable compounds are compounds with polymerizable groups, such as acrylates, methacrylates, vinyl compounds, vinyloxy compounds, propylene ethers, epoxy compounds (ethylene oxide, oxetane), and vinyl ketones. Examples of preferred compounds include those disclosed in International Publication No. 2015 / 146330, etc.

[0336] [Example]

[0337] The present invention will be described below through examples. Furthermore, the evaluation methods and compounds used in the examples are as follows.

[0338] In the synthesis example, the viscosity of the polymer solution was measured using a rotational viscometer (Toki Sangyo TVE-20L type) with a sample volume of 1.1 mL at a temperature of 25°C.

[0339] <Imidification rate of polyimide>

[0340] The polyimide solution was added to pure water, and the resulting precipitate was dried under reduced pressure at room temperature and then dissolved in deuterated dimethyl sulfoxide. ¹H-NMR was measured at room temperature using tetramethylsilane as a reference. The imidization rate [%) was calculated from the obtained ¹H-NMR spectrum using the following mathematical formula (1).

[0341] Imidification rate [%] = (1 - α × A1 / A2) × 100…(1)

[0342] In mathematical formula (1), A1 is the peak area of ​​the proton originating from the NH group that appears near the chemical shift of 10 ppm, A2 is the peak area of ​​the proton originating from other protons, and α is the ratio of the number of other protons to the number of 1 NH group proton in the polymer precursor (polyamic acid).

[0343] <Tetracarboxylic acid derivatives>

[0344]

[0345] <Diamine>

[0346]

[0347]

[0348] <Additives>

[0349]

[0350] Solvent

[0351] NMP: N-methyl-2-pyrrolidone

[0352] GBL: γ-Butyrolactone

[0353] BC: Butyl cellosolve (ethylene glycol monobutyl ether)

[0354] Synthesis of varnish

[0355] [Synthesis example 1]

[0356] Synthesis of Varnish A1

[0357] In a 100 mL three-necked flask equipped with a stirring blade and a nitrogen inlet tube, 1.49 g of the compound shown in formula (D-3) and 2.18 g of the compound shown in formula (D-8) were added, along with 54.0 g of NMP, and the mixture was stirred. Under a nitrogen atmosphere, 2.32 g of the compound shown in formula (T-1) was added to the solution, and the mixture was stirred at room temperature for 12 hours. Then, 20.0 g of GBL and 20.0 g of BC were added, and the solution was heated and stirred at 60 °C until the viscosity of the polymer in the solute reached the desired viscosity, yielding a polyamic acid solution, i.e., varnish A1, with a solute viscosity of approximately 30 mPa·s and a resin component concentration (solid component concentration) of 6% by weight.

[0358] [Synthetic Examples 2 to 9, 11 to 14]

[0359] Synthesis of varnishes A2-A9, A11 and B1-B4

[0360] The compounds used as diamines and tetracarboxylic dianhydrides were changed as shown in Tables 1 and 2. Otherwise, polyamic acid solutions, namely varnishes A2–A9, A11, and B1–B4, with a solid content concentration of 6% by weight and a viscosity of about 30 mPa·s, were synthesized in the same manner as in Synthesis Example 1. The values ​​in square brackets represent weights, and empty columns indicate that the corresponding compound was not used.

[0361] [Synthesis Example 10]

[0362] Synthesis of varnish A10

[0363] In a 100 mL three-necked flask equipped with a stirring blade and a nitrogen inlet tube, 0.98 g of compound (D-1), 0.77 g of compound (D-2), 0.26 g of compound (D-4), and 1.28 g of compound (D-8) were added, along with 44.0 g of NMP and stirred. Under a nitrogen atmosphere, 2.72 g of compound (T-1) was added to this solution and stirred at room temperature for 12 hours. Then, 0.96 g of pyridine and 3.73 g of acetic anhydride were added to this solution, and the mixture was heated at 60 °C for 4 hours to carry out a dehydration and ring-closure reaction. After the dehydration and ring-closing reaction, the solvent in the system was replaced to make the new NMP 34.0g. 50.0g of GBL and 10.0g of BC were added to it. The solution was heated and stirred at 60°C until the viscosity of the polymer of the solute reached the desired viscosity, and a polyamic acid solution with a solute viscosity of about 30mPa·s, a resin component concentration (solid component concentration) of 6% by weight, and an imidization rate of about 60% was obtained, namely varnish A10.

[0364] [Table 1]

[0365]

[0366] [Table 2]

[0367]

[0368] Varnish adjustment

[0369] [Example 1]

[0370] Varnish A1 and varnish B1 were mixed at a weight ratio of 3:7, and then diluted with an NMP / GBL / BC mixed solution (NMP / GBL / BC = 6 / 2 / 2 weight ratio) to a solid content of 4% by weight. After stirring, the mixture was filtered through a 0.2 μm filter to prepare liquid crystal alignment agent 1. The prepared liquid crystal alignment agent was spin-coated onto a glass substrate with an FFS electrode and a glass substrate with pillar spacers. After coating, the substrate was heated at 60°C for 80 seconds to evaporate the solvent, and then fired at 230°C for 30 minutes to form a liquid crystal alignment film. Linearly polarized ultraviolet light (Ushio Electric Co., Ltd.) was irradiated onto the substrate from the vertical direction through a polarizer with a polarization band of 230 nm to 310 nm using a high-pressure mercury lamp. At this point, the exposure energy was measured using a UIT-150 UV cumulative photometer (receiver: UVD-S254) manufactured by Ushio Electric Co., Ltd., and the exposure time of the linearly polarized light was adjusted to achieve 0.4 ± 0.05 J / cm at a wavelength of 254 nm. 2 Then, an additional heating process is performed at 230°C for 30 minutes.

[0371] Next, two substrates on which these liquid crystal alignment films are formed are placed face-to-face with the substrate on which the liquid crystal alignment films are formed, and a gap for injecting liquid crystal composition is formed between the face-to-face liquid crystal alignment films and they are then bonded together. At this time, the polarization directions of the linearly polarized light irradiating each liquid crystal alignment film are made parallel. A negative liquid crystal composition A is injected into this unit to fabricate a liquid crystal unit (liquid crystal display element) with a unit thickness of 4 μm.

[0372] <Negative Liquid Crystal Composition A>

[0373]

[0374] (Physical property values)

[0375] Phase transition temperature NI: 75.7℃, dielectric constant anisotropy Δε: -4.1, refractive index anisotropy Δn: 0.101, viscosity η: 14.5mPa·s.

[0376] <Evaluation of AC (Alternating Current) Image Retention Using Negative Liquid Crystal Composition A>

[0377] AC image retention was measured according to the method described in International Publication No. 2000 / 43833. Specifically, the luminance-voltage characteristic (BV characteristic) of the manufactured liquid crystal cell was measured and taken as the luminance-voltage characteristic before stress application: B(before). Then, after applying 4.5V, 30Hz AC to the liquid crystal cell for 20 minutes, the luminance-voltage characteristic (BV characteristic) was measured again. This was taken as the luminance-voltage characteristic after stress application: B(after). Here, the luminance change rate ΔB(%) was calculated using the luminance at the voltage of 1.3V for each measured luminance-voltage characteristic as the characteristic values ​​of B(before) and B(after). The smaller the value of ΔB(%), the better the AC image retention characteristic is. If ΔB is less than 3%, it is evaluated as "good"; if it is 3% or more, it is evaluated as "poor".

[0378] ΔB(%)={[B(after)-B(before)] / B(before)}×100

[0379] [Example 2, Comparative Example 1]

[0380] The liquid crystal alignment agent 2 was prepared in the same manner as in Example 1, except that the varnishes shown in Table 3 were used instead of varnishes A1 and B1, and the mixing ratios were changed to those shown in Table 3. The AC image retention was evaluated using the prepared liquid crystal alignment agent in the same manner as in Example 1. The varnishes used, the mixing ratios, and the results are shown in Table 3.

[0381] [Example 3]

[0382] Varnish A3 and varnish B3 were mixed in a weight ratio of 6:4, and then diluted with an NMP / GBL / BC mixed solution (NMP / GBL / BC = 6 / 2 / 2 weight ratio) to achieve a solids concentration of 4% by weight. A compound of formula (Ad-1) was added to this solution at an amount equivalent to 5% by weight of the solids in the solution. After stirring at room temperature for 2 hours, the mixture was filtered through a 0.2 μm filter to prepare liquid crystal alignment agent 5. Except for the method of adjusting the liquid crystal alignment agent, the AC image retention was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0383] [Examples 4-16]

[0384] Liquid crystal alignment agents 4 to 16 were prepared in the same manner as in Example 3, except that the varnishes and additives shown in Table 3 were used instead of varnishes A3 and B3, and the mixing ratios were changed to those shown in Table 3. The AC image retention was evaluated using the prepared liquid crystal alignment agents in the same manner as in Example 1. The varnishes used, the mixing ratios, and the results are shown in Table 3.

[0385] [Example 17]

[0386] Varnish A10 and varnish B2 were mixed in a weight ratio of 4:6, and then diluted with an NMP / GBL / BC mixed solution (NMP / GBL / BC = 4 / 5 / 1 weight ratio) to a solid content concentration of 4% by weight. After stirring, the mixture was filtered through a 0.2 μm filter to prepare liquid crystal alignment agent 17. The prepared liquid crystal alignment agent was used to evaluate AC image retention in the same manner as in Example 1. The varnishes used, mixing ratios, and results are shown in Table 3.

[0387] [Table 3]

[0388]

[0389] In Examples 1-17, the AC afterimage was good. On the other hand, in Comparative Example 1, the AC afterimage was poor.

[0390] [Example 18]

[0391] Instead of negative liquid crystal composition A, positive liquid crystal composition B was used. Except for the other aspects, liquid crystal cells (liquid crystal display elements) with a cell thickness of 4 μm were fabricated in the same manner as in Example 1.

[0392] <Positive Liquid Crystal Composition B>

[0393]

[0394] (Physical property values)

[0395] Phase transition temperature NI: 100.1℃, dielectric constant anisotropy Δε: 5.1, refractive index anisotropy Δn: 0.093, viscosity η: 25.6mPa·s.

[0396] [Comparative Example 2]

[0397] Except for replacing liquid crystal alignment agent 1 with comparison alignment agent 1, a liquid crystal cell (liquid crystal display element) with a cell thickness of 4 μm is fabricated in the same manner as in Example 18.

[0398] <Evaluation of AC image retention using positive liquid crystal composition B>

[0399] AC image retention was measured according to the method described in International Publication No. 2000 / 43833. Specifically, the luminance-voltage characteristic (BV characteristic) of the manufactured liquid crystal cell was measured and taken as the luminance-voltage characteristic before stress application: B(before). Then, after applying 4.5V, 30Hz AC to the liquid crystal cell for 20 minutes, the luminance-voltage characteristic (BV characteristic) was measured again. This was taken as the luminance-voltage characteristic after stress application: B(after). Here, the luminance change rate ΔB(%) was calculated using the luminance at the voltage of 1.3V for each measured luminance-voltage characteristic as the characteristic values ​​of B(before) and B(after). The smaller the value of ΔB(%), the better the AC image retention characteristic is. If ΔB is less than 5%, it is evaluated as "good"; if it is 5% or more, it is evaluated as "poor". The evaluation results are shown in Table 4.

[0400] ΔB(%)={[B(after)-B(before)] / B(before)}×100

[0401] [Table 4]

[0402]

[0403] In Example 18, the AC afterimage was good. On the other hand, in Comparative Example 2, the AC afterimage was poor.

[0404] Industrial application

[0405] If the liquid crystal alignment agent of the present invention is used, a liquid crystal alignment film that can form a liquid crystal display element with good image retention characteristics and excellent display quality can be manufactured.

Claims

1. A liquid crystal alignment agent comprising a polymer (K), said polymer (K) being at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The raw material composition of the polymer (K) comprises at least one tetracarboxylic acid derivative of formula (I) and at least one diamine having the structure of formula (II). In formula (I), *1, *1', *2, and *2' are bonding bonds, each independently bonded to a hydroxyl group, a chlorine atom, or an alkoxy group having 1 to 6 carbon atoms. At least one of the groups *1 and *1' and *2 and *2' can bond to the same oxygen atom. R b1 R b2 R b3 and R b4 Each is independently a hydrogen atom or a methyl group, with at least one being a methyl group. In formula (II), *3 and *4 are bonding bonds, each independently a bonding bond between a hydrogen atom and a carbon atom. One or both of *3 and *4 are bonding bonds to carbon atoms. A 1 It is a monovalent hydrocarbon group with 5 or more carbon atoms, or a monovalent group with 5 or more carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group.

2. The liquid crystal alignment agent according to claim 1, wherein, In the above formula (II), A 1 It is a monovalent hydrocarbon group with 5 to 10 carbon atoms, or a monovalent group with 5 to 10 carbon atoms having -O- between carbon-carbon bonds of the hydrocarbon group.

3. The liquid crystal alignment agent according to claim 2, wherein, The liquid crystal alignment agent further comprises a polymer (L), wherein the polymer (L) is a polymer selected from at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester and polyimide. The raw material composition of the polymer (L) does not contain diamines having the structure shown in formula (II).

4. The liquid crystal alignment agent according to claim 3, wherein, The structure shown in formula (II) is the same as the structure shown in formula (III). In formula (III), *3 and *4 are bonding bonds, each independently a bonding bond between a hydrogen atom and a carbon atom, wherein one or both of *3 and *4 are bonding bonds between carbon atoms. R a1 R a2 and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

5. The liquid crystal alignment agent according to claim 4, wherein, The compound represented by formula (I) is the same as the compound represented by formula (I-1).

6. The liquid crystal alignment agent according to claim 5, wherein, Diamines having the structure shown in formula (III) include at least one of the diamines shown in formulas (III-1) to (III-23). In equations (III-1) to (III-23), e is an integer from 2 to 10, and D is the structure shown in equation (V) below. R a1 R a2 and R a3 Each is independently a monovalent chain hydrocarbon group having 1 to 7 carbon atoms, or a monovalent group having 1 to 7 carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group, wherein R a1 R a2 and R a3 The total number of carbon atoms is 4 to 9.

7. The liquid crystal alignment agent according to claim 5, wherein, Diamines having the structure shown in formula (III) include at least one of the diamines shown in formulas (D-10) to (D-19).

8. The liquid crystal alignment agent according to claim 5, wherein, The starting material composition of the polymer (K) comprises at least one compound of formula (DI-4-1), (DI-5-1), or (DI-13-1). In equation (DI-5-1), m is 2 or 4.

9. A liquid crystal alignment agent, which is a liquid crystal alignment agent for a transverse electric field type liquid crystal display element in a light alignment manner, among the liquid crystal alignment agents of any one of claims 1 to 8.

10. A liquid crystal alignment film formed from any one of claims 1 to 9.

11. A liquid crystal element having the liquid crystal alignment film of claim 10.

12. A method for manufacturing a liquid crystal alignment film, comprising the following steps: The liquid crystal alignment agent according to any one of claims 1 to 9 is coated on the substrate; The substrate is fired; and The substrate is irradiated with polarized ultraviolet light.

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