Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element
Patent Information
- Application Number
- TW111116747
- Authority / Receiving Office
- TW · TW
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2021-05-06
- Filing Date
- 2022-05-04
- Publication Date
- 2026-10-11
- Estimated Expiration
- 2042-05-03
AI Technical Summary
Existing liquid crystal display elements using negative type liquid crystals suffer from high display defects (line burn-in), poor stability of liquid crystal alignment, and accumulation of charges leading to afterimages, especially in high-brightness applications, and conventional alignment films fail to address these issues effectively.
A liquid crystal alignment agent comprising a specific composition of polyimide precursors, epoxy-based cross-linking compounds, and polymers that enhance stability and reduce charge accumulation, allowing for low-temperature calcination without significant film loss.
The solution results in a liquid crystal display element with reduced display defects, improved alignment stability, and rapid charge dissipation, ensuring high-quality display performance even under bright conditions.
Abstract
Description
Technical Field
[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal display elements. Prior Technology
[0002] Liquid crystal display (LCD) elements are constructed by sandwiching a liquid crystal layer between a transparent substrate and an electrode. Furthermore, in LCD elements, an organic film made of organic material is used as a liquid crystal alignment film to ensure the liquid crystal achieves a desired alignment state between the substrates. That is, the liquid crystal alignment film is a constituent component of the LCD element, formed on the surface of the substrate holding the liquid crystal and in contact with the liquid crystal, and is responsible for aligning the liquid crystal in a specific direction between the substrates. Moreover, the pretilt angle of the liquid crystal can be controlled by the liquid crystal alignment film. Methods for reducing the pretilt angle, primarily by selecting a polyimide structure, are known (see Patent Documents 1 and 2). In recent years, with the increasing performance of liquid crystal display elements, in addition to applications such as large-screen and high-resolution LCD TVs, they are also used in automotive applications, such as navigation systems, dashboards, surveillance cameras, and medical camera screens. Considering the need for viewing angle characteristics, the IPS and FFS methods with excellent viewing angle characteristics among the driving methods of liquid crystal molecules have been explored. Polyimide-based liquid crystal alignment films have also been proposed for rub alignment films (see Patent Document 3). Furthermore, in IPS and FFS liquid crystal display elements, static electricity easily accumulates within the liquid crystal cells. This accumulated charge can affect the display by disrupting liquid crystal alignment or causing image retention, significantly degrading the display quality. Therefore, there is a need for a liquid crystal alignment film that can reduce the generated charge in a short time and reduce the absolute value of the accumulated charge. In addressing these issues, Patent Document 4 proposes a liquid crystal alignment agent containing polyamide or polyimide with structural units having aromatic tetracarboxylic acid residues and alicyclic tetracarboxylic acid residues, while Patent Document 5 proposes a liquid crystal alignment agent containing a polyimide precursor with a diphenylamine backbone. In addition, in recent years, considering the need to improve design flexibility, some researchers have explored flexible liquid crystal elements using PET film and polycarbonate film as substrates, and proposed liquid crystal alignment film materials suitable for low-temperature calcination treatment when the substrate calcination temperature during the formation of the liquid crystal alignment film does not reach 200°C (see Patent Document 6). [Previous Technical Documents] [Patent Literature]
[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-188761 [Patent Document 2] Japanese Patent Application Publication No. 10-123532 [Patent Document 3] International Publication No. 2019-082975 [Patent Document 4] International Publication No. 02-033481 [Patent Document 5] International Publication No. 2014-010402 [Patent Document 6] International Publication No. 2018-124167 Summary of the Invention
[0004] (The problem the invention aims to solve)
[0005] Liquid crystal display elements using transverse electric field methods such as IPS driving and FFS driving have traditionally used positive liquid crystals. However, by using negative liquid crystals, the transmission loss at the top of the electrodes is reduced and the contrast is improved. Therefore, some people have recently been exploring liquid crystal display elements that use negative liquid crystals. However, after investigation, the inventors of this case learned that if negative liquid crystal is used as the liquid crystal material, the incidence of display defects (line burn-in) is high, making it impossible to obtain liquid crystal display elements with excellent display quality. Furthermore, in IPS and FFS liquid crystal cells, if the liquid crystal alignment stability is low, the liquid crystal will not return to its initial state during prolonged operation, leading to decreased contrast and image retention. Therefore, the stability of liquid crystal alignment is crucial. In addition, with the recent increase in backlight brightness in high-brightness liquid crystal display elements, the visibility of image retention caused by accumulated charge has also increased. Therefore, compared to the past, there is a greater need for liquid crystal alignment films that can reduce the absolute value of accumulated charge and reduce the charge generated in a short time. On the other hand, in order to address the aforementioned display defects and low-temperature calcination treatment, a liquid crystal alignment agent containing an epoxy compound with a tertiary amine structure, as described in Patent Document 6, was explored. However, it was found that the polyimide film was easily damaged during alignment treatment, and conventional technology could not solve all of these problems.
[0006] In view of the above, the object of the present invention is to provide a liquid crystal alignment agent that can produce a liquid crystal display element with a low incidence of display defects (line burn-in) even when using negative liquid crystal as the liquid crystal material. Furthermore, the present invention provides a liquid crystal alignment agent that can produce a liquid crystal alignment film with high stability of liquid crystal alignment, can reduce the absolute value of accumulated charge, and can reduce the charge generated in a short time. Moreover, the present invention provides a liquid crystal alignment agent that can produce a liquid crystal alignment film in which film loss is suppressed during low-temperature calcination treatment below 200°C.
[0007] In order to achieve the above objectives, the inventors conducted various studies and found that the following liquid crystal alignment agent is the most suitable for achieving the above objectives, thus completing the present invention. (Methods for solving problems)
[0008] Based on the above knowledge, the present invention has the following key points. A liquid crystal alignment agent comprising the following polymers (A), (B), and crosslinking compound (C). Polymer (A): Polyimide obtained by amide-imidizing the reaction product of a diamine containing a diamine represented by the following formula (d0) and a diamine represented by the following formula (dD) with a tetracarboxylic acid derivative, i.e., a polyimide precursor. Polymer (B): is a polyimide precursor resulting from the reaction of a diamine (dD'B) represented by "HN(R)-YD'-N(R)-H" (YD' represents a divalent organic group with an intramolecular "-N(D')-" (D' represents a protecting group that is removed and replaced by a hydrogen atom upon heating). R is synonymous with R in formula (dD).) and a diamine (dB) represented by the following formula (excluding diamine (dD'B)). However, this polyimide precursor does not possess a propylene ring structure. Crosslinking compound (C): An epoxy compound represented by the following formula (E n). [Chemistry 1] In formula (d 0), the two Ars each independently represent a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and any hydrogen atom on the aforementioned rings can also be replaced by a monovalent group. L o represents -O-(-Ar'-O-)n- (n is an integer from 0 to 3. Ar' represents a divalent benzene ring or biphenyl structure, and any hydrogen atom on the aforementioned ring can be replaced by a monovalent group. When there are multiple Ar's, they can be the same or different.), -(CH 2)n- (n is an integer from 2 to 18), or a group in which at least a portion of the -CH 2- of the -(CH 2)n- is replaced by any one of -O-, -C(=O)-, or -OC(=O)-. In formula (dD), YD represents a divalent organic group with the radical "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom due to heating). In formulas (d0) and (dD), each R independently represents a hydrogen atom or a monovalent organic group. [Chemistry 2] YB represents a divalent organic group that meets the following conditions (1) and (2). R is synonymous with R in the above formula (d 0). Condition (1): The structure does not contain nitrogen-containing atoms in the group consisting of heterocycles selected from nitrogen-containing atoms and secondary or tertiary amine groups (excluding amine groups from the group "-N(D')-" (D' represents a protecting group that is removed by heating and replaced by a hydrogen atom). Condition (2): It does not have a side chain group with more than 6 carbons. [Chemistry 3] a is an integer from 2 to 4, Ra is an a-valent organic group, and the bonding sites with a N are aliphatic carbon atoms.
[0009] Furthermore, in this specification, Boc represents the tert-butoxycarbonyl group. Halogen atoms may include fluorine, chlorine, bromine, and iodine. The amide ratio referred to in this specification is the proportion of amide groups in the total stoichiometry of amide and carboxyl groups (or their derivatives) of tetracarboxylic dianhydride or its derivatives. (Effects of the invention)
[0010] By using the liquid crystal alignment agent of this invention, a liquid crystal display element with a low incidence of display defects (line burn-in) can be obtained even when using negative liquid crystal as the liquid crystal material. Furthermore, a liquid crystal alignment film with high liquid crystal alignment stability, capable of reducing the absolute value of accumulated charge and reducing the generated charge in a short time, can be obtained. Moreover, since a liquid crystal alignment film with suppressed film loss during alignment processing at low temperatures below 200°C can be obtained, a liquid crystal display element with excellent display quality can be obtained. Implementation
[0011] <Polymer (A)> The liquid crystal alignment agent of this invention contains a polyimide polymer (A), which is obtained by amide imidizing a polyimide precursor, a reaction product containing a diamine represented by formula (d0) and a diamine represented by formula (dD) above, and a tetracarboxylic acid derivative. By achieving the above-described state, the high-temperature treatment necessary for thermoamide imidization is unnecessary. Furthermore, due to the presence of a specific diamine component, the obtained liquid crystal alignment film exhibits high stability in liquid crystal alignment, resulting in a liquid crystal display element with a low incidence of display defects (line burn-in). The aforementioned polymer (A) is obtained by amide-imidizing a polyimide precursor derived from a tetracarboxylic acid derivative containing tetracarboxylic acid dianhydride and a diamine containing a specific diamine. Regarding the amide-imidization rate of the polyimide in polymer (A), considering the viewpoint of reducing the incidence of defects, 10-100% is preferred. Furthermore, the lower limit of the amide-imidization rate is ideally 10%, 20% is better, 50% is better, and 70% is optimal; the upper limit of the amide-imidization rate is ideally 100%, 99% is better, and 95% is even better. Specific examples of materials used in the manufacture of polymer (A) and the manufacturing method are detailed below.
[0012] The liquid crystal alignment agent of the present invention contains a diamine component used in the manufacture of the polyimide polymer (A), which contains a diamine represented by the following formula (d0) and a diamine represented by the following formula (dD). The diamine represented by the following formula (d0) and the diamine represented by the following formula (dD) can be used alone or in combination of two or more. [Chemistry 4] The definitions of each symbol in the formula are the same as those described above.
[0013] The hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring of Ar in formula (d0) and Ar' contained in Lo can also be replaced by, for example: halogen atoms, alkyl groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), alkenyl groups with 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms), alkoxy groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), fluoroalkyl groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), fluoroalkenyl groups with 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms), fluoroalkoxy groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), hydroxyl groups, alkoxycarbonyl groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), cyano groups, nitro groups, etc.
[0014] The diamine represented by the above formula (d0) is preferably selected from 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, and the following formula (d0-1)~(d Compounds represented by 0-10), 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)undecane, etc. At least one diamine from the group consisting of 1,12-bis(3-aminophenoxy)dodecane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthyl)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, and 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine is preferred. [Chemistry 5]
[0015] Regarding the diamine represented by the above formula (dD), from the viewpoint of ideally obtaining the effects of the present invention, it is preferable to list aromatic diamines (dn1) or aromatic diamines (dn2). Aromatic diamine (dn1) is an aromatic diamine having one aromatic ring in the molecule, wherein at least one of any hydrogen atoms on the aromatic ring is substituted by a monovalent group having a group "-N(D)-". Aromatic diamine (dn2) is an aromatic diamine having two aromatic rings in the molecule, wherein the two aromatic rings are selected from single bonds, -CH2-, -C(CH3)2-, -O-, -C(=O)-, -OC(=O)-, -NR-C(=O)- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a group "-D"), -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a group "-D"), an alkyl group having 2 to 20 carbon atoms, and any -CH group of the alkyl group. An aromatic diamine is an aromatic diamine consisting of a divalent group (Ln) linked by a divalent group substituted with -O-, -Si(CH3)2-, -C(=O)-, -OC(=O)-, -NR-C(=O)- (where R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), or -NR- (where R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), and satisfying at least one of the following conditions (i) or (ii): (i) any hydrogen atom on the aromatic ring is substituted with a monovalent group having "-N(D)-", and (ii) the aforementioned divalent group (Ln) has a radical "-N(D)-". The aforementioned aromatic ring, for example, is a benzene ring, a naphthalene ring, or an anthracene ring, preferably a benzene ring or a naphthalene ring, with a benzene ring being more preferred. Furthermore, any hydrogen atom on the aforementioned aromatic ring may be replaced by a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a carboxyl group, a halogen atom, a monovalent organic group having 1 to 5 carbon atoms containing a fluorine atom, or a monovalent organic group in which a portion of the hydrogen atoms on the aforementioned alkyl group having 1 to 5 carbon atoms is replaced by a hydroxyl group.
[0016] The D in the radical "-N(D)-" indicates a protecting group that is removed and replaced by a hydrogen atom upon heating. There are no particular restrictions on whether the organic group can be decomposed and transformed into the radical "-NH-" by heat. Examples of organic groups D that can be removed by heat include carbamate esters such as benzyloxycarbonyl, 9-pyromethoxycarbonyl, allyloxycarbonyl, and tertiary butoxycarbonyl. However, considering the good efficiency of heat-induced removal, the ability to remove at relatively low temperatures, and the release of harmless gases during removal, tertiary butoxycarbonyl is particularly preferred.
[0017] The diamine represented by the above formula (dD) is preferably selected from the diamines of the following formulas (dD-1) to (dD-7). [Chemistry 6] In formulas (dD-2), (dD-6), and (dD-7), R represents a hydrogen atom or a third butoxycarbonyl group.
[0018] The ideal content of diamine represented by the above formula (d 0) is preferably 50 to 95 mol% relative to the total content of the aforementioned diamine component used in the manufacture of polymer (A), and even more preferably 50 to 90 mol%.
[0019] The ideal content of the diamine in the above formula (d D) is preferably 5 to 50 mol% relative to the total content of the aforementioned diamine component used in the manufacture of polymer (A), and more preferably 10 to 50 mol%.
[0020] In addition to the diamines mentioned above, the diamines used in the manufacture of the polymer (A) in the liquid crystal alignment agent of this invention can be various diamines (hereinafter also referred to as other diamines 1) depending on the desired characteristics of the liquid crystal alignment agent. Each of the aforementioned other diamines 1 can be used alone, or two or more can be used in combination. Other diamines include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro- 4,4'-Diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5-diaminonaphthalene, 1, 6-Diaminonaphthalene, 1,7-Diaminonaphthalene, 2,5-Diaminonaphthalene, 2,6-Diaminonaphthalene, 2,7-Diaminonaphthalene, 3,3'-Diaminodiphenylmethane, 3,4'-Diaminodiphenylmethane, 4,4'-Diaminodiphenylmethane, 4,4'-Sulfodiphenylamine, 3,3'-Sulfodiphenylamine, bis(4-aminophenyl)silane, bis(3- (aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4'-thiodiphenylamine, 3,3'-thiodiphenylamine, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-extrinphenylbis(4-aminobenzoate), 1,4-extrinphenylbis(3-aminobenzoate), 1,3-extrinphenylbis(4-aminobenzoate), 1,3-extrinphenylbis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate; 4,4'-diaminoazobenzene or diaminodiphenylacetylene Diamines with photoaligning groups, such as diaminotolan; diamines with photopolymerizable groups at the end, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines with free radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone and 2-(4-(2-hydroxy-2-methylpropionic acid)phenoxy)ethyl-3,5-diaminobenzoate; diamines with amide bonds, such as 4,4'-diaminophenylaniline; and diamines with urea bonds, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenylethyl)urea.2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminodiphenyl ketone, 1,4-bis(4-aminobenzyl)benzene; 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, N-(3-(1H-imidazol-1-yl)propyl-3,5-diaminobenzylamine, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-azolyl]-aniline, or a heterocyclic diamine represented by formulas (z-1) to (z-13), or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N Diamines with a diphenylamine structure, such as N'-dimethylbenzidine or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, are represented by structures having at least one nitrogen-containing group (excluding amine groups derived from the radical "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom upon heating). These are also referred to below as specific nitrogen-containing structures. Examples include 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, and 4,4'-diamino-3,3'-dihydroxybiphenyl. Diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid, and other diamines containing a carboxyl group;1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamines with a steroid skeleton such as cholesteryloxy-3,5-diaminophenyl, cholesteryloxy-3,5-diaminophenyl, cholesteryloxy-2,4-diaminophenyl, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate, and 3,6-bis(4-aminophenyloxy)cholestan; the following formula ( Diamines represented by (V-1) to (V-2); diamines containing siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; noncyclic aliphatic diamines such as m-xylene diamine, 1,3-propane diamine, tetramethylene diamine, pentamethylene diamine, and hexamethylene diamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, and 4,4'-methylenebis(cyclohexylamine); and diamines with two amino groups bonded by any of the formulas (Y-1) to (Y-167) as described in International Publication No. 2018 / 117239. [Chemistry 7] [Chemistry 8] [Chemistry 9] In formula (V-1), m and n are integers from 1 to 3 (but satisfy 1 ≤ m + n ≤ 4), j is an integer of 0 or 1, X 1 represents -(CH 2) a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH 3)-, -NH-, -O-, -CH 2O-, -CH 2-OCO-, -COO-, or -OCO-, R 1 represents a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 3 to 10 carbon atoms, an alkoxy group with 3 to 10 carbon atoms, or an alkoxyalkyl group with 3 to 10 carbon atoms. In formula (V-2), X2 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R2 represents an alkyl group with 1 to 20 carbon atoms containing fluorine atoms, or an alkyl group with 3 to 20 carbon atoms. In the above formula, when there are two of m, n, X 1, and R 1, each of them has the above definition independently.
[0021] When using diamines of formulas (d0) and (dD) above, and also using other diamines 1, the amount of the other diamine 1 used is preferably 5 to 40 mol% relative to the total diamine content used in the manufacture of polymer (A), more preferably 10 to 40 mol%. Furthermore, the total content of diamines of formulas (d0) and (dD) above is preferably 95 mol% or less, and preferably 90 mol% or less, relative to the total diamine content used in the manufacture of polymer (A).
[0022] <Tetracarboxylic acid derivatives> The tetracarboxylic acid derivative component used in the manufacture of the polymer (A) of this invention can be not only tetracarboxylic dianhydride, but also its derivatives, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, tetracarboxylic acid dialkyl ester dihalides, etc. The aforementioned tetracarboxylic acid derivative component can be a single tetracarboxylic dianhydride or its derivative, or two or more can be used in combination.
[0023] Specific examples of the aforementioned tetracarboxylic dianhydrides or their derivatives include acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or their derivatives. From the viewpoint of ideally achieving the effects of the present invention, it is preferable to contain tetracarboxylic dianhydrides or their derivatives having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring (hereinafter collectively referred to as tetracarboxylic acid derivatives having specific substructures), and even more preferably, tetracarboxylic dianhydrides or their derivatives having at least one substructure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. Furthermore, aromatic tetracarboxylic acid dianhydrides are acid dianhydrides obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group bonded to the aromatic ring. Acyclic aliphatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of the four carboxyl groups bonded by a chain hydrocarbon structure. However, they do not necessarily have to consist solely of a chain hydrocarbon structure; some may also have alicyclic or aromatic ring structures. Alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Furthermore, they do not necessarily consist solely of alicyclic structures; some may also possess chain hydrocarbon structures or aromatic ring structures. The tetracarboxylic acid derivative components that can be used in the synthesis of the above polymer (A) are preferably tetracarboxylic dianhydrides or their derivatives (hereinafter collectively referred to as specific tetracarboxylic acid derivatives).
[0024] Acyclic aliphatic tetracarboxylic anhydrides such as 1,2,3,4-butanetetracarboxylic anhydride; 1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3,4- Cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 4-(2,5-di-side-oxytetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic dianhydride, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2 [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclic [2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; benzopyrene dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalamide Aromatic tetracarboxylic acid dianhydrides include 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, ethylene glycol bis(triphenyl)carboxylic acid anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, 4,4'-carbonyldiphthalic acid anhydride, 4,4'-oxydi(1,4-epoxyphenyl)bis(phthalic acid) dianhydride, or 4,4'-methylenedi(1,4-epoxyphenyl)bis(phthalic acid) dianhydride; in addition, tetracarboxylic acid dianhydrides described in Japanese Patent Application Publication No. 2010-97188, etc.
[0025] More preferred examples of the aforementioned specific tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3- Difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 5-(2,5-disideloxytetrahydrofuran) 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic acid bicyclo[3.3.0]octane-2:4,6:8-dianhydride, benzopyrene dicarboxylic acid ... Anhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic anhydride, 3,3',4,4'-biphenyl ether tetracarboxylic anhydride, 1,4,5,8-naphthalene tetracarboxylic anhydride, 2,3,6,7-naphthalene tetracarboxylic anhydride, 3,3',4,4'-biphenyl ether tetracarboxylic anhydride, 3,3',4,4'-biphenyl tetracarboxylic anhydride, 2,2',3,3'-biphenyl tetracarboxylic anhydride, or derivatives thereof.
[0026] The ideal proportion of the above-mentioned tetracarboxylic acid derivatives with specific substructures or specific tetracarboxylic acid derivatives relative to the total tetracarboxylic acid derivative components used is 10 mol% or more, 20 mol% or more is better, and 50 mol% or more is even better.
[0027] <Polymer(B)> The liquid crystal alignment agent of this invention contains a polymer (B), which is a divalent organic group consisting of a diamine (dD'B) represented by "HN(R)-YD'-N(R)-H" (YD' represents a protecting group with an intramolecular "-N(D')-" (D' represents a protecting group that is removed and replaced by a hydrogen atom upon heating). R and R in formula (dD) are synonymous.) and a diamine (dD'B) represented by the above formula (dB) (excluding diamine (dD'B)) and a tetracarboxylic acid derivative component, which is a polyimide precursor. However, the above polymer (B) is a polyimide precursor that does not have a propylene ring structure. By including the aforementioned diamine (dD'B) in the diamine component used in the manufacture of polymer (B), when a liquid crystal alignment film is formed, polymer (B) can be concentrated in the polyimide layer from polymer (A). Therefore, the film strength of polymer (B) is improved, and film loss during alignment processing is suppressed. Furthermore, the diamine component used in the manufacture of polymer (B) includes the diamine represented by the above formula (dB). Here, the divalent organic group YB contained in the diamine (dB) meets the above conditions (1) and (2). By using the state under condition (1), the basicity of the polymer decreases, and the thermoimidization reaction of polymer (B) is suppressed, thus a liquid crystal alignment film with high film strength can be obtained. Furthermore, by using the state under condition (2), the alignment regulation force of liquid crystals in IPS and FFS methods is increased, and the alignment stability of the obtained liquid crystal alignment film can be improved. Here, a diamine with a structure consisting of a nitrogen-containing heterocycle selected from the group consisting of a nitrogen-containing atom and a secondary or tertiary amine group (excluding amine groups derived from the group "-N(D')-"), which has two groups "-NHR" (R is synonymous with R in the above formula (d B)). can be exemplified by other diamines of the above polymer (A) as an example of a diamine with a specific nitrogen-containing structure.
[0028] The diamine represented by the above formula (d B) is preferably an aromatic diamine (I) having one benzene ring; a diamine (II-a) having two benzene rings linked by a single bond; or an aromatic diamine (II-b) having two benzene rings linked by a divalent group, wherein the divalent group is an oxygen atom or an organic group having 1 to 3 carbon atoms, and the two benzene rings are linked by the same atom. However, the aromatic diamine (I), aromatic diamine (II-a), and aromatic diamine (II-b) are diamines other than the above-mentioned diamines (d D'B) and meet the above conditions (1) and (2). More ideal specific examples of diamines represented by the above formula (dB) can be listed as follows: diamines represented by the formula (dM) described below, compounds represented by formulas (d0-1) to (d0-10) above, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthoxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, and 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, etc. Phenylacetylbenzene, 1,4-Phenylbenzenebis(4-aminobenzoate), 1,4-Phenylbenzenebis(3-aminobenzoate), 1,3-Phenylbenzenebis(4-aminobenzoate), 1,3-Phenylbenzenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, the above-mentioned diamines with photoalignment groups, the above-mentioned diamines with amide bonds, the above-mentioned diamines with urea bonds, or 1,4-bis(4-aminobenzyl)benzene, etc.
[0029] Specific examples of the aforementioned diamines (dD'B), including ideal examples, can be listed. The aforementioned diamines (dD'B) can be used alone or in combination of two or more. Furthermore, specific examples of D' in the basis "-N(D')-", including ideal states, can be listed as structures exemplified by D in the basis "-N(D)-". The ideal content of diamine in the above formula (d D'B) is 5 to 40 mol% relative to the total diamine content of the diamine component used in the manufacture of polymer (B), and 10 to 40 mol% is even more ideal.
[0030] From the viewpoint of ideally achieving the effects of the present invention, the diamine component used in the manufacture of polymer (B) should preferably contain a diamine represented by the following formula (dM). [Chemistry 10] LM represents a single bond, -CH 2-, -CO-, -O-, or -C(CH 3) 2-. L M' represents a single bond or -(CH 2) m- (m is an integer from 1 to 2). Ar M represents a divalent benzene ring, and any hydrogen atom on the aforementioned ring can be substituted with a monovalent group. When multiple Ar Ms exist, they can be the same or different. Multiple Rs independently represent hydrogen atoms or monovalent organic groups. n is an integer from 0 to 1.
[0031] The hydrogen atoms on the benzene ring of Ar M can also be replaced by halogen atoms, alkyl groups with 1 to 5 carbon atoms, alkenyl groups with 2 to 5 carbon atoms, alkoxy groups with 1 to 5 carbon atoms, fluoroalkyl groups with 1 to 5 carbon atoms, fluoroalkenyl groups with 2 to 5 carbon atoms, fluoroalkoxy groups with 1 to 5 carbon atoms, hydroxyl groups, alkoxycarbonyl groups with 1 to 5 carbon atoms, hydroxyl groups, carboxyl groups, cyano groups, nitro groups, etc.
[0032] Ideal concrete examples of diamines represented by the above formula (dM) include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 3-aminobenzylamine, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino)ethyl)aniline, 4 -(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro- 4,4'-Diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 3,3'-diaminodiphenylmethane, 3,4'- Diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2'-bis(4-aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminodiphenyl ketone, and other diamines 1, the above-described carboxyl-containing diamines. Among them, p-phenylenediamine, m-phenylenediamine, 3-aminobenzylamine, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ketone, and 4,4'-diaminodiphenyl ether are more ideal.
[0033] The aforementioned diamines (dM) can be used alone or in combination of two or more. The ideal content of the diamine in the above formula (dM) is preferably 60-95 mol% of the total diamine component used in the manufacture of polymer (B), and even better if it is 60-90 mol%.
[0034] As a diamine component used in the manufacture of polymer (B), diamines other than the diamines (dD'B) and (dM) mentioned above (hereinafter also referred to as other diamines 2) may also be used. A specific example of other diamine 2 is a diamine used to obtain the polymer (A) mentioned above and meeting the conditions (1) and (2) above.
[0035] Specific examples of the tetracarboxylic acid derivative component used in the manufacture of polymer (B), including ideal examples, can be the same compounds as those exemplified in polymer (A). The tetracarboxylic acid derivative component used in the manufacture of polymer (B) is preferably the aforementioned tetracarboxylic acid derivative having a specific substructure or a specific tetracarboxylic acid derivative; ideally, a more ideal example of the aforementioned specific tetracarboxylic acid derivative should be used. Furthermore, the aforementioned tetracarboxylic acid derivative having a specific substructure or a specific tetracarboxylic acid derivative is preferably present in a concentration of 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more, relative to all the tetracarboxylic acid derivative components used in the manufacture of polymer (B). Furthermore, considering the viewpoint of obtaining a liquid crystal alignment film that reduces the absolute value of accumulated charge and can reduce the generated charge in a short time, it is preferable that the tetracarboxylic acid derivative component used in the manufacture of the above-mentioned polymer (B) contains the above-mentioned aromatic tetracarboxylic acid dianhydride or its derivative, wherein a tetracarboxylic acid dianhydride or its derivative having a benzene ring structure is preferred. More preferably, it is an aromatic tetracarboxylic acid dianhydride or its derivative exemplified by the above-mentioned specific tetracarboxylic acid derivative. The tetracarboxylic acid derivative used in the manufacture of polymer (A) may be the same as or different from the tetracarboxylic acid derivative used in the manufacture of polymer (B).
[0036] From the viewpoint of ideally obtaining the effects of the present invention, the content ratio of polymer (A) to polymer (B), in terms of the mass ratio of [polymer (A)] / [polymer (B)], is ideally 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and even more preferably 20 / 80 to 80 / 20.
[0037] <Manufacturing methods of polymer (A) and polymer (B)> The polyimide precursors such as polyamide or polyamide ester used in the manufacture of polymer (A) and polymer (B) contained in the liquid crystal alignment agent of the present invention can be synthesized, for example, by the following methods.
[0038] (Synthesis of polyamides) The synthesis of polyacrylic acid is carried out by reacting a diamine containing the aforementioned diamine with a tetracarboxylic acid derivative containing the aforementioned tetracarboxylic dianhydride or its derivative in an organic solvent. The ideal ratio of tetracarboxylic dianhydride to diamine in the polyacrylic acid synthesis reaction is 0.5 to 2 equivalents of anhydride groups relative to 1 equivalent of the amino groups of the diamine, more preferably 0.8 to 1.2 equivalents. Similar to conventional polycondensation reactions, the closer the equivalent of the anhydride groups in the tetracarboxylic dianhydride is to 1 equivalent, the larger the molecular weight of the resulting polyacrylic acid becomes. In the synthesis of polyacrylic acid, the ideal reaction temperature is -20~150℃, and 0~100℃ is even more ideal. Furthermore, the ideal reaction time is 0.1~24 hours, and 0.5~12 hours is even more ideal. The synthesis reaction of polyamide can be carried out at any concentration, preferably 1-50% by mass, more preferably 5-30% by mass. The reaction can be carried out at a high concentration initially, and then additional solvent can be added.
[0039] Specific examples of the aforementioned organic solvents include cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidineone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.
[0040] (Synthesis of polyamides) Polyamide esters can be obtained, for example, by the following known methods: [I] reacting the polyamide obtained by the above methods with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, [III] reacting a tetracarboxylic acid diester dihalide with a diamine, etc.
[0041] (Synthesis of polyimide) Polyimide can be obtained by cyclizing (nimidizing) the above-mentioned polyimide precursor. Methods for nimidizing polyimide precursors include thermal nimidization by directly heating a solution of the polyimide precursor or catalytic nimidization by adding a catalyst to a solution of the polyimide precursor.
[0042] The temperature at which the polyimide precursor is thermally amided in solution is typically 100-400°C, preferably 120-250°C. It is preferable to remove the water generated during the amided reaction from the system.
[0043] Catalytic amide imidization of polyimide precursors can be carried out by adding an alkaline catalyst and an acid anhydride to a solution of the polyimide precursor, preferably at -20 to 250°C, more preferably at 0 to 180°C with stirring. The amount of alkaline catalyst is preferably 0.5 to 30 moles of the amide group, more preferably 2 to 20 moles, and the amount of acid anhydride is preferably 1 to 50 moles of the amide group, more preferably 3 to 30 moles. Examples of alkaline catalysts include pyridine and triethylamine. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and phenylmethyltetracycline anhydride. The amide imidization rate resulting from catalytic amide imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.
[0044] When recovering the polyimide precursor or polyimide generated from the reaction solution of the polyimide precursor or polyimide, the reaction solution is simply added to a solvent to allow precipitation. Solvents used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butylceryl ketone, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water.
[0045] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good alignment of the liquid crystal display element can be ensured.
[0046] <End-capping agent> In this invention, when synthesizing polyimide precursors and polyimides, tetracarboxylic acid derivative components containing tetracarboxylic dianhydride or its derivatives, and diamine components containing the aforementioned diamines, can be used, along with appropriate end-capping agents, to synthesize end-sealed polymers. End-sealed polymers have the effect of increasing the film hardness of liquid crystal alignment films obtained by coating and improving the adhesion between the sealant and the alignment film. In this invention, examples of the polyimide precursor and the terminal groups of the polyimide include amine, carboxyl, anhydride, or groups derived from the capping agent described later. Amine, carboxyl, and anhydride groups can be obtained using conventional condensation reactions or by sealing the ends using the capping agents described below.
[0047] End-capping agents, such as acetic anhydride, maleic anhydride, naphthalic 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, 4-ethynylphthalic anhydride, etc.; dibutyl dicarbonate, diallyl dicarbonate, etc.; acrylonitrile chloride, methacrylic chloride, fumes... Chlorocarbonyl compounds such as alkali, chloroacetyl, and chloroacetyl; 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, and n-octylamine; isocyanates with unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.
[0048] The preferred ratio of the capping agent to the total 100 moles of diamine used is 0.01 to 20 moles, and even better is 0.01 to 10 moles.
[0049] <Liquid crystal alignment agent> The liquid crystal alignment agent of the present invention contains polymer (A) and polymer (B) and a crosslinking compound (C) described later. In addition to polymer (A) and polymer (B), the liquid crystal alignment agent of the present invention may also contain other polymers. Examples of other polymers include polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene or its derivatives, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates. Other polymers can be used alone or in combination of two or more. Ideally, the proportion of other polymers relative to the total number of polymers in the liquid crystal alignment agent should be less than 30 parts by mass, 1 to 25 parts by mass is better, and 1 to 20 parts by mass is even better.
[0050] Liquid crystal alignment agents are used to fabricate liquid crystal alignment films. Considering the formation of a uniform thin film, they are typically in the form of a coating liquid. The liquid crystal alignment agent of this invention is preferably in the form of a coating liquid containing the aforementioned polymer components and an organic solvent.
[0051] The organic solvents contained in the above coating solution are not particularly limited as long as the polymer components can be uniformly dissolved, such as: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionic acid, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinedione, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N- Dimethylpropanediolamine, 3-butoxy-N,N-dimethylpropanediolamine, 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, N-cyclohexyl-2-pyrrolidone (these are also collectively referred to as "good solvents"), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanediolamine, 3-butoxy-N,N-dimethylpropanediolamine, or γ-butyrolactone are preferred. The content of good solvent is preferably 20-99% by mass of the total solvent contained in the liquid crystal alignment agent, 20-90% by mass is even better, and 30-80% by mass is especially good.
[0052] Furthermore, for the organic solvents contained in the liquid crystal alignment agent, it is preferable to use a mixed solvent that, in addition to the solvents mentioned above, also includes solvents that improve the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent (also known as undesirable solvents). Specific examples of undesirable solvents used are as follows, but are not limited to these. The content of undesirable solvents is ideally 1-80% by mass of the total solvents contained in the liquid crystal alignment agent, 10-80% by mass is better, and 20-70% by mass is especially preferred. The type and content of undesirable solvents can be appropriately selected according to the coating equipment, coating conditions, coating environment, etc. of the liquid crystal alignment agent.
[0053] Unsuitable solvents, such as: 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, propyl carbonate, ethyl carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2 1-Propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, 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, cyclohexyl acetate, 4-methyl-2-pentyl 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, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.
[0054] 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.
[0055] Ideal solvent combinations of good and bad solvents include: N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone with propylene glycol diacetate, N,N-dimethyllactamine with diisobutyl ketone, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate, and N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and dipropylene glycol monomethyl ether. N-Ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone with dipropylene glycol dimethyl ether, N,N-dimethyllactamine with ethylene glycol monobutyl ether, N,N-dimethyllactamine with propylene glycol diacetate, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol monoethyl ether and butylceroxose acetate, N-methyl-2-pyrrolidone with diethylene glycol monomethyl ether and butylceroxose acetate, N,N-Dimethyllactic acid with diethylene glycol diethyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monobutyl ... N-methyl-2-pentanone with propylene glycol diacetate, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol dimethyl ether, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutyl ketone, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutylmethanol, N-methyl-2-pyrrolidone with γ-butyrolactone with dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone with propylene glycol monobutyl ether with... Dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether with dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with propylene glycol diacetate, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with diisobutyl ketone, N-ethyl-2-pyrrolidone with γ-butyrolactone with diisobutyl ketone, N-ethyl-2-pyrrolidone with N,N-dimethyllactamidine with diisobutyl ketone, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether with ethylene glycol monobutyl ether acetate, γ-butyrolactone with ethylene glycol monobutyl ether acetate with dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate with propylene glycol dimethyl ether N-methyl-2-pyrrolidone with 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with cyclohexyl acetate and diacetone alcohol, cyclohexanone with propylene glycol monomethyl ether, cyclopentanone with propylene glycol monomethyl ether, N-methyl-2-pyrrolidone with cyclohexanone with propylene glycol monomethyl ether, tetramethylurea with 4-hydroxy-4-methyl-2-pentanone, tetramethylurea with propylene glycol diacetate, N,N-dimethylpropionic acid with propylene glycol monobutyl ether, tetramethylurea with propylene glycol monobutyl ether, tetramethylurea with cyclohexanone with propylene glycol monomethyl ether, N,N-dimethylpropionic acid with propylene glycol monomethyl ether, N,N-dimethylpropionic acid with ethylene glycol monobutyl ether acetate, N,N-dimethylpropionic acid with ethylene glycol monobutyl ether, tetramethylurea with propylene glycol monomethyl ether, N,N-Dimethylpropionic acid with cyclohexanone and diethylene glycol diethyl ether, N,N-diethylmethionic acid with propylene glycol monomethyl ether, N,N-diethylmethionic acid with 4-hydroxy-4-methyl-2-pentanone, N,N-diethylmethionic acid with propylene glycol monomethyl ether, etc.
[0056] <Crosslinked compound (C)> The liquid crystal alignment agent of this invention contains the aforementioned crosslinking compound (C). Because of this state, the crosslinking reaction with the epoxy crosslinking agent occurs during calcination, thus suppressing the thermoiminization reaction, that is, suppressing the thermoiminization reaction of the amide precursor contained in the polymer (B) component. Therefore, the amount of amide-iminized structure in the obtained liquid crystal alignment film is reduced, resulting in a liquid crystal alignment film with a lower absolute value of accumulated charge and the ability to reduce the generated charge in a short time. In the liquid crystal alignment agent of the present invention, the content of the crosslinking compound (C) is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 1 to 15 parts by mass. Specific examples of the aforementioned crosslinking compound (C) include N,N,N',N'-tetracyclooxypropyl-1,2-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,3-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,4-diaminocyclohexane, bis(N,N-dicyclooxypropyl-4-aminocyclohexyl)methane, bis(N,N-dicyclooxypropyl-2-methyl-4-aminocyclohexyl)methane, and bis(N,N-dicyclooxypropyl-2-methyl-4-aminocyclohexyl)methane. Compounds such as propyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,4-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,4-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)benzene, and compounds represented by the formulas (EN-1) to (EN-5). Crosslinking compounds (C) can be used alone or in combination of two or more.
[0057] [Chemistry 11]
[0058] The liquid crystal alignment agent of the present invention may also contain additional components other than polymers (A), (B) and crosslinking compounds (C) (hereinafter also referred to as additive components). Such additive components include: adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant; compounds other than crosslinking compounds (C) for improving the strength of the liquid crystal alignment film (hereinafter also referred to as other crosslinking compounds); dielectric or conductive materials for adjusting the dielectric constant and resistance of the liquid crystal alignment film; amide imidization promoters, etc.
[0059] Other crosslinking compounds mentioned above may be selected from at least one crosslinking compound from the following groups: crosslinking compounds other than crosslinking compound (C) that have an ethylene oxide group, namely crosslinking compound (C1); crosslinking compounds that have at least one substituent selected from oxetane, terminal isocyanate group, oxazolinyl group, cyclic carbonate group, hydroxyl and alkoxy group, namely crosslinking compound (C2); and crosslinking compounds that have a polymerizable unsaturated group, namely crosslinking compound (C3).
[0060] Specific examples of the aforementioned crosslinking compounds (C1) include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetracyclooxypropyl-2,4-hexanediol, bisphenol A type epoxy resins such as jER828 (manufactured by Mitsubishi Chemical Corporation), and jER807 (manufactured by Mitsubishi Chemical Corporation). This text appears to be a list of epoxy resins and names, possibly related to bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins (e.g., YX-8000, YX6954BH30, YX6954BH30, EPPN-201, phenolic varnish epoxy resins), cresol varnish epoxy resins (e.g., ortho, meta, para), triepoxypropyl isocyanurate (e.g., TEPIC), and CELLOXIDE. A more coherent and accurate translation would require the full context of each type of epoxy resin. Compounds include alicyclic epoxy resins such as 2021P (manufactured by Daicel Chemical Industry Co., Ltd.), N,N,N',N'-tetracyclooxypropyl-1,4-phenylenediamine, N,N,N',N'-tetracyclooxypropyl-2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(N,N-dicyclooxypropyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane, and tetra(epoxypropoxymethyl)methane. In addition, compounds described in paragraph
[0037] of Japanese Patent Application Publication No. 10-338880 and compounds described in International Patent Publication No. 2017 / 170483 may be listed. Specific examples of the aforementioned crosslinkable compounds (C2) and (C3) include: compounds having two or more oxocyclic butyl groups as described in paragraphs
[0170] to
[0175] of International Publication No. 2011 / 132751; compounds having capped isocyanate groups such as CORONATEAP Stable M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATEMS-50 (all manufactured by Tosoh Corporation), TAKENATEB-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals Corporation). Compounds; compounds containing an acezoline group, such as 2,2'-bis(2-acezoline), 2,2'-bis(4-methyl-2-acezoline), 2,2'-bis(5-methyl-2-acezoline), 1,2,4-tris(2-acezoline-2)-benzene, and EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); as described in paragraphs
[0025] to
[0030] and
[0032] of International Publication No. 2011 / 155577. Compounds containing cyclic carbonate groups; N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane and other compounds containing hydroxyl and alkoxy groups; glycerol mono(meth)acrylate, glycerol di(meth)acrylate (1,2-,1,3-mixture), glycerol tri(meth)acrylate, glycerol 1,3-diglycerol di(meth)acrylate, neopentyl tert-methyl acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate.
[0061] The above-mentioned compounds are examples of cross-linking compounds, but are not limited to these. For example, other components disclosed in International Publication No. 2015 / 060357, pages 53
[0105] to 55
[0116] . Furthermore, cross-linking compounds may also be a combination of two or more.
[0062] In the liquid crystal alignment agent of the present invention, the content of crosslinking compounds (C1) to (C3) is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of polymer components contained in the liquid crystal alignment agent, and more preferably 1 to 15 parts by mass.
[0063] The aforementioned sealing aids include, 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxy Functional silane compounds such as methylpropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanate propyltriethoxysilane. When using functional silane compounds, it is preferable that their content is 0.1 to 30 parts by mass relative to 100 parts by mass of polymer components contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.
[0064] The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected considering viscosity, volatility, etc., preferably 0.5 to 15% by mass, more preferably in the range of 1 to 10% by mass. The ideal range of solid content concentration depends on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, a solid content concentration of 1.5 to 4.5% by mass is preferred. When using printing, a solid content concentration of 3 to 9% by mass is preferred, thereby achieving a solution viscosity of 12 to 50 mPa·s. When using inkjet printing, a solid content concentration of 1 to 5% by mass is preferred, thereby achieving a solution viscosity of 3 to 15 mPa·s.
[0065] <Liquid crystal alignment film, liquid crystal display element> The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be a horizontally aligned or vertically aligned (VA type) liquid crystal alignment film, especially suitable for horizontally aligned liquid crystal display elements such as IPS or FFS types. The liquid crystal display element of the present invention includes the above-mentioned liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured by, for example, a method including the following steps (1) to (3). (1) Step of coating liquid crystal alignment agent onto substrate On one side of a substrate having a patterned transparent conductive film, the liquid crystal alignment agent of the present invention is applied using a suitable coating method such as roll coating, spin coating, printing, or inkjet coating. Here, the substrate material is not particularly limited as long as it is a highly transparent substrate; acrylic substrates, polycarbonate substrates, and other plastic substrates can be used together with glass substrates and silicon nitride substrates. Furthermore, for reflective liquid crystal display elements, if it is a single-sided substrate, an opaque material such as a silicon wafer can also be used; in this case, the electrodes can also be made of light-reflecting materials such as aluminum. Moreover, when manufacturing IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and a counter substrate without electrodes are used. (2) The step of calcining the coating film. After the liquid crystal alignment agent is coated, to prevent dripping of the coated liquid crystal alignment agent, it is preferable to first perform preheating (pre-baking). The pre-baking temperature is preferably 30~200℃, more preferably 40~150℃, and even more preferably 40~100℃. The pre-baking time is preferably 0.25~10 minutes, more preferably 0.5~5 minutes. It is also preferable to further perform a heating (post-baking) step. The subsequent baking temperature is preferably 80~200℃, more preferably 120~180℃. The post-baking time is preferably 5~200 minutes, more preferably 10~100 minutes. The film thickness formed in this way is ideally 5~300nm, and more preferably 10~200nm.
[0066] The coating formed by the above steps (1) or (2) can be used directly as a liquid crystal alignment film, or the coating can be subjected to alignment capability imparting treatment. Alignment capability imparting treatments can include: friction treatment, for example, rubbing the coating in a certain direction with a roller wound with a cloth made of fibers such as nylon, silk, or cotton; and photoalignment treatment, irradiating the coating with polarized or unpolarized radiation.
[0067] In photoalignment processing, the radiation used to irradiate the coating can be, for example, ultraviolet light or visible light containing wavelengths of 150-800 nm. When the radiation is polarized, it can be linearly polarized or partially polarized. Furthermore, when using linearly polarized or partially polarized radiation, irradiation can be performed perpendicular to the substrate surface, obliquely, or a combination thereof. When irradiating with unpolarized radiation, the irradiation direction is oblique. (3) Steps for fabricating liquid crystal cells Prepare two substrates with liquid crystal alignment films formed as described above, and place a liquid crystal composition between the two opposing substrates. Specifically, the following two methods can be listed. First, the two substrates are first arranged facing each other with their respective liquid crystal alignment films facing each other, separated by a gap (cell gap). Then, the peripheries of the two substrates are bonded together using a sealant. Liquid crystal composition is injected into the cell gaps separated by the substrate surfaces and the sealant until it contacts the film surface, and then the injection holes are sealed.
[0068] Furthermore, the second method is called the ODF (One Drop Fill) method. A UV-curable sealant, for example, is applied to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed. Then, liquid crystal composition is dropped onto a predetermined number of locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded together with the liquid crystal alignment film faces facing each other, pressing the liquid crystal composition onto the entire substrate so that it contacts the film surface. Then, the entire substrate is irradiated with UV light to harden the sealant. In either case, it is further heated until the liquid crystal composition reaches the temperature of the isotropic phase, and then slowly cooled to room temperature to remove flow alignment issues during liquid crystal filling for a more ideal result. Furthermore, when the coating is subjected to friction treatment, the two substrates are arranged at a predetermined angle to each other with the friction direction of each coating, for example, in an orthogonal or antiparallel manner. The sealant may include, for example, epoxy resin containing a hardener and alumina spheres as spacers. There are no particular limitations on the liquid crystal composition; it may be a composition containing at least one liquid crystal compound (liquid crystal molecule), and examples include liquid crystal compositions exhibiting a nematic phase (hereinafter also referred to as nematic liquid crystals), liquid crystals exhibiting a smectic phase, or liquid crystal compositions exhibiting a cholesteric phase, with nematic liquid crystals being preferred. Furthermore, various liquid crystal compositions with positive or negative dielectric anisotropy may be used. Hereinafter, liquid crystal compositions with positive dielectric anisotropy are also referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are also referred to as negative liquid crystals. The aforementioned liquid crystal composition may also include liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloalkenes, steroid skeletons, benzene rings, or naphthalene rings. It may also include compounds having two or more rigid sites (mesogen skeletons) exhibiting liquid crystal properties within the molecule (e.g., rigid biphenyl structures, or biphenyl structures linked by alkyl groups to form a dual mesogen compound). Furthermore, considering the need to improve the alignment of the liquid crystal, the aforementioned liquid crystal composition may contain more additives. Examples of such additives include photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., Merck S-811); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors. Positive LCDs include those manufactured by Merck such as ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081. Negative liquid crystal displays, such as MLC-6608, MLC-6609, MLC-6610, MLC-7026, or MLC-7026-100 manufactured by Merck. Furthermore, an example of a liquid crystal containing a compound with a polymerizable group is MLC-3023 manufactured by Merck.
[0069] Furthermore, depending on the need, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: polarizing plates made of a polarizing film called "H film" by extending polyvinyl alcohol to absorb iodine through a cellulose acetate protective film holding the edges, or polarizing plates composed of the H film itself.
[0070] The liquid crystal alignment film of this invention, in addition to the liquid crystal alignment film for the purposes described above, can be applied to various other applications, such as liquid crystal alignment films for phase retardation films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission and scattering type liquid crystal dimming elements. Furthermore, it can also be used for applications other than liquid crystal alignment films, such as: protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, and motor insulating films (gate insulating films for flexible displays).
[0071] The liquid crystal display element of this invention can be effectively applied to devices with various functions, such as clocks, portable games, word processors, laptops, navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various screens, LCD TVs, information displays, and other display devices. [Example]
[0072] The following examples illustrate the invention in more detail, but the invention is not limited thereto. The abbreviations of the compounds and the methods for determining their properties are described below. (Diamine) [Chemistry 12]
[0073] (Tetracarboxylic acid dianhydride) [Chemistry 13]
[0074] (Cross-linked compounds) [Chemistry 14]
[0075] (Sealing agent) [Chemistry 15]
[0076] (End-capping agent) [Chemistry 16]
[0077] (Organic solvents) NMP: N-methyl-2-pyrrolidone GBL: γ-Butyrolactone BCS: Butylcerox (ethylene glycol monobutyl ether)
[0078] <Determination of acetilimation rate> 20 mg of polyimide powder was placed in an NMR sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Scientific Co., Ltd.)), and 0.53 mL of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) was added. The solution was then dissolved completely by ultrasound. The solution was measured at 500 MHz using an NMR spectrometer (JNW-ECA500) (manufactured by Nippon Electronics Data Corporation). The amide ratio was determined using protons from structures that remained unchanged before and after amide amide amide amide amide amide as reference protons. The cumulative peak value of this proton, along with the cumulative peak value of protons from the NH group of amide acid appearing around 9.5 ppm to 10.0 ppm, was calculated using the following formula. Acrylimide rate (%) = (1 - α·x / y) × 100 In the above formula, x is the cumulative value of the proton peak from the NH group of acetic acid, y is the cumulative value of the reference proton peak, and α is the ratio of the number of reference protons to 1 NH proton of acetic acid when polyacetic acid (aceimide content is 0%).
[0079] [Polymer Synthesis] <Synthesis example 1> 8.60 g of DA-2 (35.2 mmol), 5.34 g of DA-4 (9.59 mmol), and 7.65 g of DA-3 (19.1 mmol) were measured into a 300 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. NMP was added to bring the solid concentration to 12% by mass, and the solution was dissolved by stirring while introducing nitrogen. While stirring this diamine solution under water cooling, 9.32 g of CA-1 (41.6 mmol) was added, followed by the addition of NMP to bring the solid concentration to 15% by mass. The solution was stirred at 40°C under nitrogen for 3 hours. Then, 2.82 g of CA-2 (14.3 mmol) was added, and NMP was added again to bring the solid concentration to 15% by mass. The solution was stirred at 23°C under nitrogen for 4 hours to obtain a polyacrylic acid solution (PAA-A-1). 80.0 g of the polyamide solution (PAA-A-1) obtained above was taken into a 300 mL Erlenmeyer flask equipped with a stir bar. 70.0 g of NMP, 6.97 g of acetic anhydride, and 1.80 g of pyridine were added. The mixture was stirred at room temperature for 30 minutes, and then reacted at 55 °C for 3 hours. This reaction solution was added to 560 g of methanol, and the precipitate was obtained by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 °C to obtain polyimide powder. The amide content of this polyimide was 75%. Take 9.00 g of the polyimide powder into a 300 mL Erlenmeyer flask equipped with a stir bar, add 6.0 g of NMP3, and stir at 50 °C for 20 hours to dissolve it, thereby obtaining a solution of polyimide (PI-A-1) with a solid content of 20% by mass. Table 1 shows the types and amounts of diamines and tetracarboxylic acid derivatives used in preparing the solution of poly(PI-A-1) obtained in Synthetic Example 1, the presence or absence of E-1, and the amide ratio.
[0080] <Synthesis example 2> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 8.04 g of DA-1 (40.2 mmol), 4.36 g of DA-3 (10.9 mmol), and 12.2 g of DA-4 (21.9 mmol) were measured and added. 98.4 g of NMP was added, and the mixture was stirred while being supplied with nitrogen to dissolve the DA-1. While stirring this diamine solution under water cooling, 9.40 g of CA-3 (47.4 mmol) was added, followed by 37.6 g of NMP. The mixture was stirred at 50°C for 2 hours under nitrogen. Then, 4.65 g of CA-2 (23.7 mmol) and 18.6 g of NMP were added, and the mixture was stirred at 23°C for 2 hours under nitrogen to obtain a polyacrylic acid solution (PAA-A-2). Take 100g of the obtained polyacrylic acid solution into a 200mL Erlenmeyer flask equipped with a stir bar, add 1.24g of E-1 (5.68mmol), and stir at 40℃ for 15 hours to obtain a solution of end-capped polyacrylic acid (PAA-A-3). 100 g of the above (PAA-A-3) solution was taken into a 200 mL Erlenmeyer flask equipped with a stir bar, and 6.7 g of NMP, 14.2 g of acetic anhydride, and 4.70 g of pyridine were added. The mixture was stirred at room temperature for 30 minutes, and then reacted at 60 °C for 4 hours. This reaction solution was added to 650 g of methanol, and the precipitate was obtained by filtration. The precipitate was washed with methanol and dried under reduced pressure at 80 °C to obtain polyimide powder (imidization rate: 89%). Furthermore, 9.60 g of the polyimide powder was taken into a 100 mL Erlenmeyer flask equipped with a stir bar, 0.4 g of NMP was added, and the mixture was stirred at 70 °C for 24 hours to dissolve it, thereby obtaining a polyimide (PI-A-2) solution with a solid content of 12% by mass. The types and amounts of diamines and tetracarboxylic acid derivatives used in preparing the solution of poly(PI-A-2) obtained in Synthetic Example 2, the presence or absence of E-1, and the amide ratio are shown in Table 1.
[0081] <Synthesis example 3> 38.26 g of DA-3 (96.0 mmol) and 44.41 g of DA-8 (224.0 mmol) were measured into a 1 L four-necked flask equipped with a stirrer and a nitrogen inlet tube. 606.2 g of NMP was added to bring the solid concentration to 12% by mass, and the mixture was stirred while being supplied with nitrogen to dissolve it. While stirring this diamine solution under water cooling, 48.32 g of CA-2 (246.4 mmol) and 166.1 g of NMP were added, and the mixture was stirred under water cooling for 2 hours under nitrogen atmosphere. Then, 18.83 g of CA-4 (64.0 mmol) and 76.6 g of NMP were added, and the mixture was stirred at 50°C under nitrogen atmosphere for 15 hours to obtain a polyacrylic acid (PAA-B-1) solution with a solid concentration of 15% by mass.
[0082] <Synthesis Examples 4~7> Using the diamine and tetracarboxylic acid derivatives shown in Table 2 below, and using the same organic solvent as in Synthesis Example 3, and following the same procedure as in Synthesis Example 3, solutions of polyamides (PAA-B-2) to (PAA-B-5) as shown in Table 2 below were obtained.
[0083] <Synthesis example 8> Measure 39.65 g of DA-8 (200.0 mmol) and 42.66 g of DA-5 (200.0 mmol) into a 1 L four-necked flask equipped with a stirrer and a nitrogen inlet tube. Add 603.6 g of NMP to make the solid content concentration 12% by mass, and stir while introducing nitrogen gas to dissolve it. While stirring this diamine solution under water cooling, add 74.52 g of CA-2 (380.0 mmol) and 285.1 g of NMP, and stir for 4 hours under nitrogen and water cooling to obtain a polyacrylic acid (PAA-B-6) solution with a solid content concentration of 15% by mass. The types and amounts of diamines and tetracarboxylic acid derivatives used in preparing the polyacrylic acid (PAA-B-6) solution obtained in Synthetic Example 8 are shown in Table 2.
[0084] [Table 1]
[0085] [Table 2]
[0086] [Preparation of Liquid Crystal Alignment Agents] <Examples 1-4, Comparative Examples 1-5> Weigh out the amounts of polyamide and polyimide solutions obtained in Synthesis Examples 1-8 as shown in Table 3 into 200 mL Erlenmeyer flasks. While stirring, add NMP, GBL, NMP solution containing 10% by mass of crosslinking compound, GBL solution containing 1% by mass of binding agent, and BCS in sequence. Stir at room temperature for 2 hours to obtain liquid crystal alignment agents (1)-(9).
[0087] [Table 3]
[0088] [Fabrication of Liquid Crystal Display Components Using FFS Method] A liquid crystal cell comprising a liquid crystal display element having a fringe field switching (FFS) mode. First, prepare the substrate for the electrodes. The substrate is a glass substrate measuring 30mm × 35mm and 0.7mm thick. An ITO electrode with a patterned surface, constituting the first opposing electrode, is formed on the substrate. A SiN (silicon nitride) film, formed using CVD, is formed on top of the first opposing electrode. The second SiN film has a thickness of 500nm and acts as an interlayer insulating film. A comb-shaped pixel electrode, formed by patterning the ITO film, is placed on top of the second SiN film as the third layer, forming two pixels, the first and second pixels. Each pixel is approximately 10mm long and 5mm wide. The first opposing electrode and the third pixel electrode are electrically insulated by the second SiN film.
[0089] The third layer of pixel electrodes has a comb-like shape formed by multiple electrode elements with a width of 3μm that bend at an inner angle of 160° in the central part and are arranged in parallel with a 6μm interval. Each pixel has a first region and a second region, with the line connecting the bends of multiple electrode elements as the boundary.
[0090] Comparing regions 1 and 2 of each pixel, the formation directions of the electrode elements constituting them are different. That is, when taking the direction of the bend connecting the aforementioned electrode elements as a reference, in region 1 of the pixel, the electrode elements are formed at an 80° clockwise angle, and in region 2 of the pixel, the electrode elements are formed at an 80° counterclockwise angle. In other words, regions 1 and 2 of each pixel are configured such that the direction of the rotational movement (in-plane switching) of the liquid crystal within the substrate surface caused by the voltage applied between the pixel electrode and the opposing electrode is opposite to each other.
[0091] Then, the liquid crystal alignment agents (1) to (9) were filtered through a filter with a pore size of 1.0 μm and then spin-coated onto the prepared substrate with the above-mentioned electrode. After drying on a hot plate at 80°C for 5 minutes, the substrate was calcined in an IR oven at 150°C for 20 minutes to obtain a polyimide film with a thickness of 60 nm. The polyimide film was then rubbed with a cloth (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 30 mm / sec, push-in length: 0.3 mm, rubbing direction: 180° relative to the direction of the folded portion of the above-mentioned multiple electrode elements connecting the pixel electrode of the third layer), and then washed with pure water by ultrasonic irradiation for 1 minute, and water droplets were removed by blowing. After drying at 80°C for 15 minutes, a substrate with a liquid crystal alignment film was obtained. Furthermore, for a glass substrate with a 4μm high columnar spacer and an ITO electrode formed on the back side of the opposing substrate, the same process was performed to obtain a substrate with a liquid crystal alignment film that had undergone alignment treatment. These two substrates with liquid crystal alignment films were grouped together. A sealant (Mitsui Chemicals XN-1500T) was printed on one substrate, retaining the liquid crystal injection port, and the other substrate was attached, so that the liquid crystal alignment film surfaces faced each other and the friction direction was antiparallel. Then, a heat treatment at 150°C for 60 minutes was performed to harden the sealant, creating a 4μm intercellular spacer. Negative liquid crystal MLC-7026-100 (Merck) was injected into this vacant cell using a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-type liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour, placed at 23°C overnight, and used for evaluating liquid crystal alignment.
[0092] Fabrication of liquid crystal cells for voltage retention measurement After filtering the liquid crystal alignment agents (1) to (9) through a 1.0 μm filter, they were spin-coated onto a substrate with electrodes (a glass substrate with dimensions of 30 mm x 40 mm and a thickness of 1.1 mm, on which a rectangular ITO electrode with a width of 10 mm x a length of 40 mm and a thickness of 35 nm had already been formed). After drying on a hot plate at 50 °C for 5 minutes, the substrate was calcined in an IR oven at 150 °C for 20 minutes to form a coating with a thickness of 60 nm, thus obtaining a substrate with a liquid crystal alignment film. The liquid crystal alignment film was then subjected to friction alignment treatment with a helical cloth (YA-20R manufactured by Yoshikawa Chemical) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 30 mm / sec, push-in length: 0.3 mm), and then washed with ultrasonic irradiation in pure water for 1 minute. After removing water droplets by blowing air, the substrate was dried at 80 °C for 15 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with liquid crystal alignment films were prepared. On one substrate, 4μm spacers were dispersed on the surface of the liquid crystal alignment film. A sealant (Mitsui Chemicals XN-1500T) was then printed onto the film, and the other substrate was attached to it with the rubbing direction opposite and the film surfaces facing each other. The substrate was then heated at 150°C for 60 minutes to harden the sealant, thus creating a void. This void was then injected with negative liquid crystal MLC-7026-100 (Merck) using a depressurized injection method. The injection port was sealed to obtain the liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight to obtain a liquid crystal cell for voltage retention measurement.
[0093] [evaluate] 1. Orientation stability evaluation driven by long-term communication Liquid crystal cells manufactured for use in the fabrication of liquid crystal display elements using the aforementioned FFS method. Using this liquid crystal cell, an AC voltage of ±10V at a frequency of 60Hz was applied for 168 hours over a high-brightness backlight (light source: LED, brightness: 20000cd / m2) with a surface temperature of 50°C. Afterward, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature for one day. After placement, the liquid crystal cell is positioned between two polarizing plates orthogonal to the polarizing axis. The backlight is then illuminated without applied voltage, and the arrangement angle of the liquid crystal cell is adjusted to minimize the transmitted light brightness. The rotation angle required to bring the liquid crystal cell from the angle at which the second region of the first pixel becomes darkest to the angle at which the first region of the first pixel becomes darkest is calculated and defined as angle Δ. The same angle Δ is calculated for the second pixel by comparing the second and first regions. Regarding the stability of liquid crystal alignment, a value less than 0.4° is defined as "good" and rated as "poor" when the angle Δ is greater than 0.4°. The evaluation results are shown in Table 4.
[0094] 2. Measurement of the easing time of accumulated charge A liquid crystal cell, fabricated in the same manner as described above (for FFS-type liquid crystal display elements), is placed between two polarizing plates arranged with their polarization axes perpendicular to each other. With the pixel electrode and the opposing electrode short-circuited and at the same potential, LED backlight is shone from below the two polarizing plates. The angle of the liquid crystal cell is adjusted to minimize the brightness of the LED backlight transmitted light measured above the two polarizing plates. Then, while applying an AC voltage of 60Hz to the liquid crystal cell, the VT curve (voltage-transmittance curve) is measured. The AC voltage at which the relative transmittance reaches 23% is defined as the driving voltage. To evaluate image retention, an AC voltage of 60 Hz with a relative transmittance of 23% was applied to drive the liquid crystal cells, while a DC voltage of 1 V was simultaneously applied for 120 minutes. Afterward, the DC voltage was stopped, and the cells were driven solely by the AC voltage for 15 minutes. If the relative transmittance gradually decreases to below 25% within 10 minutes from the point when the DC voltage is stopped, it is defined as "good". If it takes more than 10 minutes for the relative transmittance to decrease to below 25%, it is defined as "bad". Furthermore, the image retention evaluation using the above method was conducted at a temperature of 40°C for the liquid crystal cells. The evaluation results are shown in Table 4.
[0095] 3. Evaluation of the amount of charge accumulated due to AC drive A liquid crystal cell, fabricated in the same manner as described above (for FFS-type liquid crystal display elements), is placed between two polarizing plates arranged with their polarization axes perpendicular to each other. With the pixel electrode and the opposing electrode short-circuited and at the same potential, LED backlight is shone from below the two polarizing plates. The angle of the liquid crystal cell is adjusted to minimize the brightness of the LED backlight transmitted light measured above the two polarizing plates. Then, while applying an AC voltage of 60Hz to the liquid crystal cell, the VT curve (voltage-transmittance curve) is measured. The AC voltage at which the relative transmittance reaches 23% is defined as the driving voltage. For image retention evaluation, an AC voltage of 60 Hz with a relative transmittance of 100% was applied to drive the liquid crystal cells for 60 minutes. Then, an AC voltage with a relative transmittance of 23% was applied, and the applied voltage at which the flicker energy was minimized was measured while scanning the DC voltage. The absolute value of this applied voltage at which the flicker energy was minimized was taken as the charge accumulation. A value exceeding 100 mV was defined as "poor," and a value below 100 mV was defined as "good." Furthermore, the image retention evaluation using the above method was conducted at a temperature of 40°C for the liquid crystal cells. The evaluation results are shown in Table 4.
[0096] 4. Stability evaluation of voltage retention rate under backlighting The liquid crystal cell used for the voltage retention rate determination was subjected to a voltage of 1V for 60μsec at a temperature of 60°C. The voltage after 167ms was measured, and the voltage that could be maintained was calculated and defined as the voltage retention rate. This was taken as the initial voltage retention rate. Then, regarding the backlight resistance test, the liquid crystal cell was placed under high-brightness backlight (light source: LED, brightness: 20000 cd / m²) with a surface temperature of 50°C for 168 hours. The voltage retention rate of the liquid crystal cell was measured in the same manner as above. This voltage retention rate was taken as the voltage retention rate after the resistance test. Regarding the backlight withstand capability for voltage retention rate, a value obtained by subtracting the withstand capability test value from the initial value is rated as "good" if it is less than 5%, and as "poor" if it is more than 5%. The evaluation results are shown in Table 4.
[0097] 5. Evaluation of Friction Resistance Liquid crystal alignment agents (1) to (9) were spin-coated onto an ITO substrate. After drying on a hot plate at 60°C for 1 minute and 30 seconds, the substrate was calcined in an IR oven at 150°C for 20 minutes to form a coating with a thickness of 100 nm. The liquid crystal alignment film was then subjected to two consecutive rounds of rubbing with a spinning cloth (Yoshikawa Chemical YA-20R) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, pushing length: 0.5 mm). The surface of the film was observed using a confocal laser microscope. The presence of scratches was defined as "defective", and the absence of scratches was defined as "good". The evaluation results are shown in Table 4.
[0098] The evaluation results of the liquid crystal display elements using the liquid crystal alignment agents of Examples 1-4 and Comparative Examples 1-5 described above are shown in Table 4 below. [Table 4] Liquid crystal alignment agent Orientation stability under long-term driving force The easing time of charge accumulation Charge accumulation in AC drive Voltage holding rate stability Friction resistance Example 1 (1) good good good good good Example 2 (2) good good good good good Example 3 (3) good good good good good Example 4 (4) good good good good good Comparative Example 1 (5) good bad good good bad Comparative Example 2 (6) good good bad good bad Comparative Example 3 (7) bad good good good bad Comparative Example 4 (8) good good good good bad Comparative Example 5 (9) bad good bad bad good [Industrial applicability]
[0099] The liquid crystal alignment agent of this invention is useful for the formation of liquid crystal alignment films in a wide range of liquid crystal display elements, such as those using IPS driving mode and FFS driving mode.
[0100] Furthermore, the entire contents of the specification, scope of application and abstract of Japanese Patent Application No. 2021-078636, filed on May 6, 2021, are hereby cited and incorporated as disclosures in the specification of this invention.
Claims
1. A liquid crystal alignment agent, characterized by comprising the following polymer (A), polymer (B), and crosslinking compound (C), wherein polymer (A) is a polyimide obtained by amide imidizing a diamine component containing a diamine represented by formula (d0) and a diamine represented by formula (dD) with a tetracarboxylic acid derivative component; polymer (B) is a diamine component composed of a diamine (dD'B) represented by "HN(R)-YD'-N(R)-H" (YD' represents a diamine component containing a diamine (dD'B) represented by "-N(D')-" (D' represents a protecting group that is removed and replaced by a hydrogen atom upon heating), R and R in formula (dD) are synonymous) and a tetracarboxylic acid derivative component, wherein the reaction product is a polyimide precursor containing a diamine component containing a diamine represented by formula (d0) and a diamine represented by formula (dD) (excluding diamine (dD'B)). The product is a polyimide precursor, but this polyimide precursor does not have an imide ring structure. The tetracarboxylic acid derivative is an acyclic aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride, or derivatives thereof. The alicyclic tetracarboxylic dianhydride is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, or a tetracarboxylic dianhydride having at least one substructure selected from the group consisting of cyclopentane ring structures and cyclohexane ring structures. Crosslinking compound (C): An epoxy compound represented by the following formula (En), in formula (d0), each of the two Ars independently represents a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and any hydrogen atom on the ring can be replaced by a monovalent group; Lo represents -O-(-Ar'-O-)n- (n is an integer from 0 to 3, Ar' represents a divalent benzene ring or a biphenyl structure, and any hydrogen atom on the ring can be replaced by a monovalent group; when there are multiple Ar's, most of the Ar's can be the same or different), -(CH2)n- (n is an integer from 2 to 18), or a group in which at least a portion of the -CH2- of the -(CH2)n- has been replaced by any one of -O-, -C(=O)-, or -OC(=O)-; in formula (dD), YD represents a divalent organic group with the group "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom due to heating) within the molecule. In formulas (d0) and (dD), each R independently represents a hydrogen atom or a monovalent organic group, YB represents a divalent organic group that meets the following conditions (1) and (2), R is synonymous with R in the aforementioned formula (d0), Condition (1): It does not have a structure consisting of nitrogen-containing atoms selected from heterocycles containing nitrogen atoms and secondary or tertiary amine groups (excluding amine groups from the group "-N(D')-" (D' represents a protecting group that is removed by heating and replaced by a hydrogen atom), Condition (2): It does not have a side chain group with more than 6 carbon atoms, a is an integer from 2 to 4, Ra is an a-valent organic group, and the bonding site with a N is an aliphatic carbon atom.
2. The liquid crystal alignment agent as claimed in claim 1, wherein, The polyimide in polymer (A) has an imidization rate of 10-100%.
3. The liquid crystal alignment agent as requested in item 1 or 2, wherein, In the polymer (B), the diamine component contains a diamine represented by the following formula (dM): LM represents a single bond, -CH2-, -CO-, -O-, or -C(CH3)2-; LM' represents a single bond or -(CH2)m- (m is an integer from 1 to 2); ArM represents a divalent benzene ring, and any hydrogen atom on the ring can be substituted by a monovalent group; when multiple ArMs are present, the multiple ArMs can be the same or different; multiple Rs each independently represent a hydrogen atom or a monovalent organic group; n is an integer from 0 to 1.
4. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The content of the diamine represented by formula (d0) is 50 to 95 moles relative to the total content of the diamine component used in the manufacture of polymer (A).
5. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The content of the diamine represented by the formula (dD) is 5 to 50 moles relative to the total content of the diamine component used in the manufacture of polymer (A).
6. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The tetracarboxylic acid derivative component used in the manufacture of polymer (A) contains acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, or derivatives thereof.
7. The liquid crystal alignment agent as claimed in claim 6, wherein, The tetracarboxylic acid derivative component used in the manufacture of polymer (A) contains a tetracarboxylic acid dianhydride or a derivative thereof having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.
8. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The diamine represented by formula (d0) is selected from 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, compounds represented by formulas (d0-1) to (d0-10) below, 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)decane, and 1,11-bis(4-aminophenoxy)decane. At least one diamine from the group consisting of monoalkyl, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthyloxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, and 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine.
9. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The diamine represented by formula (dD) is an aromatic diamine (dn1) or an aromatic diamine (dn2). Aromatic diamine (dn1) is an aromatic diamine having one aromatic ring within the molecule, wherein at least one of the hydrogen atoms on the aromatic ring is substituted with a monovalent group having the radical "-N(D)-". Aromatic diamine (dn2) is an aromatic diamine having two aromatic rings within the molecule, wherein the two aromatic rings are selected from single bonds, -CH2-, -C(CH3)2-, -O-, -C(=O)-, -OC(=O)-, -NR-C(=O)- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), an alkyl group having 2 to 20 carbon atoms, and any -CH2- of the alkyl group is replaced by -O-, -Si(CH3)-. The divalent group (Ln) consisting of divalent groups substituted with 2-, -C(=O)-, -OC(=O)-, -NR-C(=O)- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), or -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a radical "-D"), and satisfying at least one of the following conditions: (i) any hydrogen atom on the aromatic ring is substituted by a monovalent group having "-N(D)-", or (ii) the divalent group (Ln) above has a radical "-N(D)-".
10. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The ratio of polymer (A) to polymer (B) is 10 / 90 to 90 / 10 by mass ratio of [polymer (A)] to [polymer (B)].
11. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The crosslinking compound (C) is selected from N,N,N',N'-tetracyclooxypropyl-1,2-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,3-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,4-diaminocyclohexane, bis(N,N-dicyclooxypropyl-4-aminocyclohexyl)methane, bis(N,N-dicyclooxypropyl-2-methyl-4-aminocyclohexyl)methane, and bis(N,N-dicyclooxypropyl-3-methyl-4-aminocyclohexyl)methane. The group consisting of at least one compound represented by the following formulas: alkyl, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,4-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,4-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)benzene, and compounds represented by formulas (EN-1) to (EN-5).
12. The liquid crystal alignment agent of claim 1 or 2 further contains crosslinking compounds and / or binding agents other than crosslinking compound (C).
13. A liquid crystal alignment film obtained from a liquid crystal alignment agent as claimed in any one of claims 1 to 12.
14. The liquid crystal alignment film in request item 13 is of the horizontal alignment type.
15. A liquid crystal display element comprising a liquid crystal alignment film as claimed in claim 13 or 14.
Citation Information
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