Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NISSAN CHEM CORP
- Filing Date
- 2026-01-23
- Publication Date
- 2026-08-06
Smart Images
Figure JP2026002163_06082026_PF_FP_ABST
Abstract
Description
Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element
[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film.
[0002] Liquid crystal display elements are widely used in applications ranging from small devices such as mobile phones and smartphones to relatively large applications such as televisions and monitors. Furthermore, various driving methods have been developed that differ in electrode structure and the physical properties of the liquid crystal molecules used. For example, liquid crystal display elements using various modes such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), IPS (In-Plane Switching), and FFS (Fringe Field Switching) are known. These liquid crystal display elements generally have a liquid crystal alignment film, which is essential for controlling the arrangement of liquid crystal molecules. Polyamic acids and their derivatives (e.g., polyimides) are commonly used as materials for the liquid crystal alignment film.
[0003] In recent years, cost-effectiveness during manufacturing has become important for electronic devices, such as liquid crystal display elements. For example, defective substrates generated during the manufacturing of electronic devices are sometimes reused. Specifically, if defects such as foreign matter or uneven coating occur in the liquid crystal alignment film, or if defects occur in the orientation of the liquid crystal molecules, a process is sometimes carried out in which the liquid crystal alignment film is removed from the substrate using an organic solvent, and the substrate is recovered and reused (also called rework) (see Patent Document 1).
[0004] WO2018 / 062437 publication
[0005] Furthermore, with the increasing prevalence of large-screen, high-definition liquid crystal display elements, the demand for higher quality liquid crystal display elements has become more significant than ever before. For example, moisture can penetrate into the liquid crystal display element, potentially causing corrosion of the metal wiring within the element and deterioration of the drive circuit. Therefore, a liquid crystal alignment film with low hygroscopicity is sometimes required. The inventors' research has revealed that conventional technologies cannot produce a liquid crystal alignment film that satisfies these characteristics at a high level.
[0006] The object of the present invention is to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film that is easy to rework and has low hygroscopicity, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film.
[0007] The inventors of the present invention conducted diligent research to solve the above problems and, as a result, discovered that the above problems can be solved by using a specific polymer component, thus completing the present invention.
[0008] The present invention relates to a liquid crystal alignment agent characterized by containing the following polymer (A) and polymer (B), a liquid crystal alignment film obtained from the liquid crystal alignment agent, or a liquid crystal display element having the liquid crystal alignment film, wherein at least one of polymer (A) and polymer (B) has a substructure represented by the following formula (DB-1) as a diamine-derived structural unit. Polymer (A): A polymer selected from the group consisting of a polyimide precursor having a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor has a structural unit (a1) represented by the following formula (A1). Polymer (B): A polymer selected from the group consisting of a polyimide precursor having a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor has a structural unit (b1) represented by the following formula (B1) and a structural unit (b2) represented by the following formula (B2). (In formula (A1), X １ This represents a tetravalent organic group represented by the following formula (X-1) or (X-2). Y １ This represents a divalent organic group represented by the following formula (DA-a) and does not have the substructure represented by the above formula (DB-1). R and Z each independently represent a hydrogen atom or a monovalent organic group. Multiple R and Z groups each independently have the above definitions. (In formula (X-1), R １ ~R ４Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group, and R １ ~R ４ At least one of represents a group other than a hydrogen atom in the above definition. In Formula (X-1) and Formula (X-2), * represents a bond. ) -Ar-L ０ -Ar'- (DA-a) (In Formula (DA-a), Ar and Ar' each independently represent a divalent aromatic ring group. Any hydrogen atom on the rings of Ar and Ar' may be substituted with a monovalent group. L ０ represents a single bond, -(CH ２ ) ｎ -(n is an integer from 2 to 18), -COO-, -OCO-, -NR-CO-NR'', -NR-CO-, -NR-CO-, or -(CH ２ ) ｎ - represents a divalent organic group in which any -CH ２ - is replaced with a group selected from the following group (X), and when L ０ represents a single bond, Ar and Ar' represent aromatic hydrocarbon groups; Group (X): -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-NR'', a divalent cyclic hydrocarbon group, and a divalent heterocyclic group. (R and R'' each independently represent a hydrogen atom or a monovalent organic group. However, -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-NR'' are not adjacent to each other. Also, the divalent cyclic hydrocarbon group in Group (X) does not directly bond to Ar and Ar'.) (X １’ represents a tetravalent organic group represented by the following formula (X-3). Y １’ represents a divalent organic group. R' and Z' each independently represent a hydrogen atom or a monovalent organic group. A plurality of R' and Z' each independently have the above definition.) (* represents a bond.) (X２’ This represents a tetravalent organic group represented by any of the following formulas (X-4) to (X-5). ２’ Y １’ This represents a similar definition. R' and Z' each independently represent a hydrogen atom or a monovalent organic group. Multiple R' and Z' each independently have the above definition. (* indicates a bonding action.) (In formula (DB-1), A １１ This represents a divalent aromatic ring group. B １ is, -NR-A １２ - or -A １３ Represents -. A １２ This represents a divalent aromatic ring group, A １３ A represents a divalent heterocyclic group, and R represents a hydrogen atom or a monovalent organic group. １２ They may also form a ring together (however, -A １３ (Except in the case of a divalent heterocyclic group.) * represents a bond.) In this specification, * always represents a bond. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Boc represents a tert-butoxycarbonyl group.
[0009] According to the present invention, a liquid crystal alignment agent is obtained that is easy to rework and provides a liquid crystal alignment film with low hygroscopicity, the liquid crystal alignment film is obtained, and a liquid crystal display element having the liquid crystal alignment film is obtained.
[0010] The mechanism by which the above effects of the present invention are obtained is not entirely clear, but the following is considered to be one of the contributing factors. Specifically, it is thought that the steric hindrance in the structure of polymer (B) facilitates rework, and the high hydrophobicity in the structure of polymer (B) suppresses the hygroscopicity of the liquid crystal alignment film, thus achieving the above effects.
[0011] <Polymer (A)> The liquid crystal alignment agent of the present invention is a polymer selected from the group consisting of a polyimide precursor having a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor contains a polymer (hereinafter also referred to as polymer (A)) having a structural unit (a1) represented by the above formula (A1). In this specification, "structural unit derived from a diamine" refers to, using polymer (A) as an example, the diamine "H-N(Z)-Y １ -N(Z)-H(Y) １ The definition of Z is the same as above.) The group (Y1) obtained by removing the two hydrogen atoms present on the nitrogen atom is "-N(Z)-Y １ This represents a structural unit having "-N(Z)-". Furthermore, "structural unit derived from a tetracarboxylic acid derivative" is a structural unit having a tetravalent organic group obtained by removing two anhydride groups from a tetracarboxylic dianhydride, and represents a structural unit obtained by removing the above group (Y1) from the structural unit represented by the above formula (A1). The polyimide precursor in polymer (A) of the present invention is a polymer having a structural unit (a1) represented by the following formula (A1). Note that polymer (A) may be composed of one type or two or more types, and structural unit (A1) may be one type or two or more types. (In formula (A1), X １ X represents a tetravalent organic group represented by the following formula (X-1) or (X-2). From the viewpoint of the charge relaxation rate, which will be discussed later, X １ Compared to the following equation (X-1), (X-2) is preferable. １ This represents a divalent organic group represented by the following formula (DA-a) and does not have the substructure represented by the above formula (DB-1). R and Z each independently represent a hydrogen atom or a monovalent organic group. Multiple R and Z groups each independently have the above definitions. (R １ ~R ４Each independently represents a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, a C1-C6 alkoxy group, a C2-C6 alkoxyalkyl group, a C2-C6 alkyloxycarbonyl group, or a phenyl group, R １ ~R ４ At least one of the elements represents a group other than a hydrogen atom in the above definition. * represents a bond.) -Ar-L ０ -Ar'- (DA-a) (In formula (DA-a), Ar and Ar' each independently represent an aromatic ring group. Any hydrogen atom on the Ar and Ar' rings may be substituted with a monovalent group. L ０ is a single bond, -(CH ２ ) ｎ - (n is an integer from 2 to 18), -COO-, -OCO-, -NR-CO-NR''-, -NR-CO-, -NR-CO-, or -(CH ２ ) ｎ Any -CH in - ２ - represents a divalent organic group formed by replacing a group selected from the following group (X), L ０ When R represents a single bond, Ar and Ar' represent aromatic hydrocarbon groups; Group (X): A group consisting of -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-NR''-, divalent cyclic hydrocarbon groups, and divalent heterocyclic groups. (R and R'' each independently represent a hydrogen atom or a monovalent organic group. However, -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, and -NR-CO-NR''- are not adjacent to each other.)
[0012] R in the above formula (X-1) １ ~R ４ Specific examples of alkyl groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-pentyl group, etc. １ ~R ４Specific examples of the alkenyl group having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, include vinyl groups, propenyl groups, and butynyl groups, which may be linear or branched. １ ~R ４ Specific examples of the alkynyl group having 2 to 6 carbon atoms, preferably alkynyl group having 2 to 4 carbon atoms, include, for example, an ethynyl group, a 1-propynyl group, a 2-propynyl group, and the like. １ ~R ４ Examples of monovalent organic groups containing a fluorine atom, preferably monovalent organic groups containing a fluorine atom, having 1 to 6 carbon atoms, include fluoromethyl group, trifluoromethyl group, trifluoromethoxy group, 2,2,2-trifluoroethyl group, 2,2,2-trifluoroethoxy group, pentafluoroethyl group, and pentafluoropropyl group. １ ~R ４ Specific examples of alkoxy groups having 1 to 6 carbon atoms, alkoxyalkyl groups having 2 to 6 carbon atoms, and alkyloxycarbonyl groups having 2 to 6 carbon atoms include methoxy groups, ethoxy groups, methoxymethyl groups, ethoxymethyl groups, methyloxycarbonyl groups, ethyloxycarbonyl groups, or tert-butyloxycarbonyl groups.
[0013] The above formula (X-1) is preferably a tetravalent organic group selected from the group consisting of the following formulas (x1-1) to (x1-5).
[0014]
[0015] From the viewpoint of suitably obtaining the effects of the present invention, the structural units (a1) of the polyimide precursor in polymer (A) of the present invention are preferably 60 mol% or more, and more preferably 70 mol% or more, relative to 100 mol% of the total structural units of the polyimide precursor. Furthermore, the structural units (a1) of the polyimide precursor in polymer (A) of the present invention may be 100 mol% or less, 95 mol% or less, or 90 mol% or less, relative to 100 mol% of the total structural units of the polyimide precursor.
[0016] In the above formula (A1), the monovalent organic group R is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and the methylene group of the hydrocarbon group is -O-, -S-, -CO-, -COO-, -COS-, -NR ３ -, -CO-NR ３ -, -Si(R ３ ) ２ - (However, R ３ R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. ３ If there are multiple, each R ３ They may be the same or they may be different. ２ Examples include a monovalent group A obtained by substituting with -, etc., a monovalent group obtained by substituting at least one hydrogen atom bonded to the carbon atom of the monovalent group A with a halogen atom, hydroxyl group, alkoxy group, nitro group, amino group, mercapto group, nitroso group, alkylsilyl group, alkoxysilyl group, silanol group, sulfino group, phosphino group, carboxyl group, cyano group, sulfo group, acyl group, etc., or a monovalent group having a heterocycle. Examples of monovalent organic groups of Z in formula (A1) include groups similar to R in formula (A1), including preferred embodiments.
[0017] The diamine-derived structural units having a divalent organic group represented by the above formula (DA-a) may be 60 mol% or more, or 70 mol% or more, relative to 100 mol% of the total diamine-derived structural units in the polyimide precursor of polymer (A). Furthermore, the diamine-derived components having a divalent organic group represented by (DA-a) may be 100 mol% or less, 95 mol% or less, or 90 mol% or less, relative to 100 mol% of the total diamine-derived structural units in polymer (A). In the above formula (DA-a), Ar and Ar' each independently represent a divalent aromatic ring group. Any hydrogen atom on the rings of Ar and Ar' may be substituted with a monovalent group. Examples of the divalent aromatic ring groups of Ar and Ar' include divalent aromatic hydrocarbon groups and divalent aromatic heterocyclic groups. Examples of divalent aromatic heterocyclic groups include nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, and sulfur-containing aromatic heterocyclic groups, with nitrogen-containing aromatic heterocyclic groups being preferred. Ar and Ar' may have substituents on the aromatic ring portion. These substituents include halogen atoms; C1-C3 alkyl groups; C1-C3 alkyl groups in which at least some of the hydrogen atoms are substituted with halogen atoms or hydroxyl groups; C1-C3 alkoxy groups, C1-C3 alkoxy groups in which at least some of the hydrogen atoms are substituted with at least one of the above halogen atoms and hydroxyl groups; C2-C3 alkenyl groups; C2-C3 acyl groups; C1-C3 alkylsilyl groups; C1-C3 alkoxysilyl groups; -NH(Boc), -N(Boc) ２ Examples include hydroxyl groups, nitrile groups, and so on.
[0018] Specific examples of Ar and Ar' include, as divalent aromatic hydrocarbon groups, groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a benzene ring, naphthalene ring, biphenyl structure, or anthracene ring; as divalent nitrogen-containing aromatic heterocyclic groups, groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a pyridine ring, pyrimidine ring, pyridazine ring, or pyrazine ring, or groups obtained by removing any two hydrogen atoms bonded to carbon atoms or nitrogen atoms constituting a ring in a carbazole structure, indole structure, quinoline structure, isoquinoline structure, or benzimidazole structure; as divalent oxygen-containing aromatic heterocyclic groups, groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a furan ring; and as divalent sulfur-containing aromatic heterocyclic groups, groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a thiophene ring. From the viewpoint of improving the orientation of the liquid crystal alignment film, the divalent aromatic ring groups Ar and Ar' are preferably divalent aromatic hydrocarbon groups, and more preferably substituted phenylene groups or substituted biphenyldiyl groups. In the above formula (DA-a), L ０ no- (CH ２ ) ｎ In the above formula (DA-a), n is preferably 2 to 14, and more preferably 2 to 12, from the viewpoint of favorably obtaining the effects of the present invention. ０Examples of monovalent organic groups in -NR-, -CO-NR-, -NR-CO-, -NR-COO-, and -NR-CO-NR'' include C1-C3 alkyl groups, C1-C3 alkoxy groups, C2-C3 alkenyl groups, C2-C3 acyl groups, C1-C3 alkylsilyl groups, C1-C3 alkoxysilyl groups, Boc groups, or monovalent organic groups in which at least some of the hydrogen atoms of these groups are substituted with at least one of a halogen atom and a hydroxyl group. Examples of divalent cyclic hydrocarbon groups and divalent heterocyclic groups in the above group (X) include groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a cyclic hydrocarbon group such as a benzene ring, cyclopropane ring, cyclobutane ring, or cyclohexane ring; the above-mentioned divalent nitrogen-containing aromatic heterocyclic group; the above-mentioned divalent oxygen-containing aromatic heterocyclic group; the above-mentioned divalent sulfur-containing aromatic heterocyclic group; and groups obtained by removing any two hydrogen atoms bonded to carbon atoms or nitrogen atoms constituting other heterocyclic rings other than the above-mentioned nitrogen-containing aromatic heterocyclic rings, such as a piperidine ring, piperazine ring, pyrrolidine ring, hexamethyleneimine ring, oxazoline ring, or indoline ring.
[0019] From the viewpoint of suitably obtaining the effects of the present invention, the divalent organic group represented by the above formula (DA-a) is preferably a divalent organic group selected from the group consisting of divalent organic groups represented by the following formulas (h1-1) to (h1-21) and divalent organic groups derived from the following diamine group (1).
[0020] In formulas (h1-1) to (h1-13) and (h1-15) to (h1-21), the bonding positions of the benzene ring are preferably at positions 1 and 4, and the bonding positions of the naphthalene ring are preferably at positions 2 and 6.
[0021] In equations (h1-7), (h1-8), (h1-15), and (h1-16), the two values of m may be the same or different.
[0022] Furthermore, the hydrogen atoms on the benzene rings in the following formulas (h1-1) to (h1-13), (h1-15), (h1-16), (h1-18) to (h1-20) may be substituted with methyl groups, methoxy groups, or fluorine atoms.
[0023]
[0024]
[0025]
[0026] Diamine group (1): 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3-trifluoromethyl-4,4'-diaminobiphenyl, 2-trifluoromethyl-4,4'-diaminobiphenyl, 3-fluoro-4,4'-diaminobiphenyl, 2-fluoro-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-dia Minobiphenyl, 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, 4,4'-diamino-3,3'-dihydroxybiphenyl; Diamines having an amide bond, such as 4,4'-diaminobenzanilide and diamines represented by the following formulas (Am-1) to (Am-5); Diamines having a urea bond, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenethyl)urea; 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, and diamines selected from the following formulas (Am-6) to (Am-10); 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; 1,4-bis(4-aminobenzyl)benzene;1,4-bis(p-aminobenzyl)piperazine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine; 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3' Diamines having a carboxyl group, such as 4,4'-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'-diaminodiphenylethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; the following formula (d; Ｄａ -1) to (d Ｄａ -13) Diamines having a thermally detachable group (preferably a Boc group);
[0027] The structural units derived from the tetracarboxylic acid derivative of the polyimide precursor in polymer (A) may consist only of structural units derived from the tetracarboxylic acid derivative having a tetravalent organic group represented by the above formula (X-1) or / and (X-2), or they may also contain structural units derived from other tetracarboxylic acid derivatives. The structural units derived from the tetracarboxylic acid derivative having a tetravalent organic group represented by the above formula (X-1) or / and (X-2) may be 60 mol% or more, 70 mol% or more, or 100 mol% relative to 100 mol% of the total structural units derived from the tetracarboxylic acid derivative in the polyimide precursor in polymer (A). Furthermore, the structural units derived from the tetracarboxylic acid derivative having a tetravalent organic group represented by the above formula (X-1) or / and (X-2) may be 100 mol% or less, 95 mol% or less, or 90 mol% or less relative to 100 mol% of the total structural units derived from the tetracarboxylic acid derivative in the polyimide precursor in polymer (A). The structural units derived from other tetracarboxylic acid derivatives in the polyimide precursor of polymer (A) may be 5 mol% or more, or 10 mol% or more, relative to 100 mol% of the total structural units derived from tetracarboxylic acid derivatives in the polyimide precursor of polymer (A). Furthermore, the structural units derived from other tetracarboxylic acid derivatives in the polyimide precursor of polymer (A) may be 5 to 40 mol%, 10 to 40 mol%, or 10 to 30 mol%, relative to 100 mol% of the total structural units derived from tetracarboxylic acid derivatives in the polyimide precursor of polymer (A).Other specific examples of tetracarboxylic acid derivatives include 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, and 3,3',4,4'-perfluoroisopropylidene (phthalic anhydride). 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropanoic acid dianhydride, ethylene glycol bis-anhydrotrimellitate, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, 4,4'-carbonyl diphthalic acid anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic acid) Dianhydrides, 4,4'-methylenedi(1,4-phenylene)bis(phthalic acid) dianhydrides, or other aromatic tetracarboxylic dianhydrides such as tetracarboxylic dianhydrides represented by the following formulas [CA-2] to [CA-8], [CA-11] to [CA-13], [CA-16] to [CA-17], [CA-19] to [CA-20]; tetracarboxylic dianhydrides having a tetravalent organic group represented by the above formulas (X-3) to (X-4) and the following formulas (X-6) to (X-25) Other alicyclic tetracarboxylic dianhydrides, such as aqueous compounds; tetracarboxylic dianhydrides having a tetravalent organic group represented by the above formula (X-5), or acyclic aliphatic tetracarboxylic dianhydrides such as tetracarboxylic dianhydrides represented by the following formulas (AL-1) to (AL-7), tetracarboxylic dianhydrides represented by the following formulas [CA-10], [CA-14], [CA-21], [CA-23] to [CA-25], or derivatives thereof are preferred examples. Aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the aromatic ring. Alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of 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, it is not necessary to consist solely of alicyclic structures; it may also contain a chain-like hydrocarbon structure or an aromatic ring structure in part. Acyclic aliphatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups bonded to a chain-like hydrocarbon structure. However, it is not necessary to consist solely of chain-like hydrocarbon structures; it may also contain a chain-like hydrocarbon structure or an aromatic ring structure in part.
[0028] At least one of the above polymers (A) and (B) has a substructure represented by the above formula (DB-1) as a diamine-derived structural unit. The diamine-derived structural unit having the substructure represented by the above formula (DB-1) may be 5 mol% or more, or 10 mol% or more, relative to 100 mol% of the total diamine-derived structural units in the polyimide precursor of polymer (A). Furthermore, the diamine-derived structural unit having the substructure represented by (DB-1) may be 40 mol% or less, or 30 mol% or less, relative to 100 mol% of the total diamine-derived structural units in polymer (A). The diamine-derived structural unit having the substructure represented by the above formula (DB-1) may be 5 mol% or more, or 10 mol% or more, relative to 100 mol% of the total diamine-derived structural units in the polyimide precursor of polymer (B). Furthermore, the diamine-derived portion having the substructure represented by (DB-1) may be 100 mol%, 95 mol% or less, or 90 mol% or less, relative to 100 mol% of the total diamine-derived structural units of polymer (B).
[0029] A in the above formula (DB-1) １１ and A １２Specific examples of divalent aromatic ring groups include groups obtained by removing any two hydrogen atoms bonded to carbon atoms constituting a benzene ring or naphthalene ring; divalent nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, sulfur-containing aromatic heterocyclic groups, or other heterocyclic groups. Preferred specific examples of divalent nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, sulfur-containing aromatic heterocyclic groups, and other heterocyclic groups include the structures described above. Note that A １１ and A １２ The ring portion may have substituents. Examples of such substituents include those exemplified by Ar and Ar' above. A in formula (DB-1) above １３ Specific examples of divalent heterocyclic groups include divalent nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, sulfur-containing aromatic heterocyclic groups; and other groups obtained by removing any two hydrogen atoms bonded to carbon or nitrogen atoms constituting a heterocyclic ring. The above-mentioned structures are preferred specific examples of divalent nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, sulfur-containing aromatic heterocyclic groups, and other heterocyclic rings. １３ The ring portion may have substituents. Examples of such substituents include those exemplified by Ar and Ar' above. １ NR-A １２ In this notation, R represents a hydrogen atom or a monovalent organic group. Examples of monovalent organic groups for R include C1-C3 alkyl groups, C1-C3 alkoxy groups, C2-C3 alkenyl groups, C2-C3 acyl groups, C1-C3 alkylsilyl groups, C1-C3 alkoxysilyl groups, Boc groups, phenyl groups, or monovalent organic groups in which at least some of the hydrogen atoms in these groups are substituted with at least one of a halogen atom and a hydroxyl group.
[0030] Preferred specific examples of the substructure represented by the above formula (DB-1) include the substructures represented by the following formulas (DB-1-1) to (DB-1-14). The hydrogen atoms on the ring in the following formulas (DB-1-1) to (DB-1-14) may be substituted with a monovalent organic group. (R in formulas (DB-1-1) to (DB-1-3), (DB-1-5), (DB-1-10), and R' in formula (DB-1-14) are -NR-A in formula (DB-1) １２ This is synonymous with R in (DB-1-3). Multiple Rs in (DB-1-3) may be the same or different.
[0031] Diamines having the substructure represented by the above formula (DB-1) include diamines in which H-N(Z)-(Z is the same as Z in formula (A1)) is bonded to both sides of the structures represented by the above formulas (DB-1-1) to (DB-1-2), (DB-1-10) to (DB-1-11), and the structures represented by the following formulas (DB-1-12) to (DB-1-27). (In (DB-1-18), Q represents a methyl group or a phenyl group.)
[0032] The diamine-derived structural units of the polyimide precursor in polymer (A) may be any of the following embodiments (1) to (3): (1) Composed only of diamine-derived structural units having a divalent organic group represented by the above formula (DA-a). (2) Composed only of diamine-derived structural units having a divalent organic group represented by the above formula (DA-a), in addition to diamine-derived structural units having a substructure represented by the above formula (DB-1). (3) Having other diamine-derived structural units other than the diamine having a divalent organic group represented by the above formula (DA-a) and the diamine having a substructure represented by the above formula (DB-1). The other diamine-derived structural units in the polyimide precursor in polymer (A) may be 5 mol% or more, or 10 mol% or more, relative to 100 mol% of the total diamine-derived structural units in the polyimide precursor in polymer (A).
[0033] The following diamines are specific examples of other diamines in the above embodiment (3). p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 1,4-diamino-2,5-dimethoxybenzene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, semi-aromatic diamines having a secondary amino group and a primary amino group (preferably 4-(2-(methylamino)ethyl)aniline) (where, a semi-aromatic diamine refers to a diamine in which one amino group is bonded to an aromatic ring and the other amino group is not bonded to an aromatic ring), 4-(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine, 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, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenyl] [Noxy)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;Diamines having photo-directing groups, such as aromatic diamines having a cinnamate structure, represented by 4,4'-diaminoazobenzene, diaminotran, 4,4-diaminochalcone, or [4-[(E)-3-[2-(2,4-diaminophenyl)ethoxy]-3-oxopropa-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate, or [4-[(E)-3-[[5-amino-2-[4-amino-2-[[(E)-3-[4-[4-(4,4,4-trifluorobutoxy)benzoyl]oxyphenyl]propa-2-enoyl]oxymethyl]phenyl]phenyl]methoxy]-3-oxopropa-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate; Diamines having photopolymerizable groups at their termini, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; diamines having radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl-3,5-diaminobenzoate; 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis(4-aminophenyl)silane, bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl) Nophenyl)silane, 4,4'-thiodianiline, 3,3'-thiodianiline, 4,4'-diaminobenzophenone; 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-imidazole-1-yl)propyl-3,5-diaminobenzamide, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol;2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, diamines represented by the following formulas (q-1) to (q-4); 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; diamines having siloxane bonds such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; metaxyl Acyclic aliphatic diamines such as relylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, and 4,4'-methylenebis(cyclohexylamine); and diamines in which two amino groups are bonded to a group represented by any of the formulas (Y-1) to (Y-167) described in WO2018 / 117239.
[0034] In the above formula (A1), the monovalent organic group R is preferably an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a t-butoxycarbonyl group, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.
[0035] From the viewpoint of suitably obtaining the effects of the present invention, the two Rs in formula (A1) above are each preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.
[0036] <Polymer (B)> The liquid crystal alignment agent of the present invention is a polymer selected from the group consisting of a polyimide precursor having structural units derived from a tetracarboxylic acid derivative and structural units derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor contains a polymer (hereinafter also referred to as polymer (B)) having structural units (b1) represented by the above formula (B1) and structural units (b2) represented by the following formula (B2).
[0037] The polymer (B) of the present invention has a structural unit (b1) represented by the following formula (B1) and a structural unit (b2) represented by the following formula (B2). (In formula (B1), X １’ This represents a tetravalent organic group represented by the following formula (X-3). Y １’ R' represents a divalent organic group. R' and Z' each independently represent a hydrogen atom or a monovalent organic group. Multiple R' and Z' each independently have the above definitions. (* indicates a bonding action.) (In formula (B2), X ２’ This represents a tetravalent organic group represented by any of the following formulas (X-4) to (X-5). ２’ Y １’ This represents a similar definition. R' and Z' each independently represent a hydrogen atom or a monovalent organic group. Multiple R' and Z' each independently have the above definition. (* indicates a bonding action.)
[0038] Y in the above formulas (B1) and (B2) １’ and Y ２’ Specific examples of divalent organic groups in this include a divalent organic group represented by the following formula (DA-a) (however, without having the substructure represented by the above formula (DB-1)), a divalent organic group having the substructure represented by the above formula (DB-1), or other divalent organic groups derived from diamines as exemplified in polymer (A). The divalent organic group represented by the above formula (DA-a) or the diamine-derived structural units having the divalent organic group derived from diamines as exemplified in polymer (A) may be 5 mol% or more, or 10 mol% or more, relative to 100 mol% of the total diamine-derived structural units in the polyimide precursor in polymer (B). Furthermore, the divalent organic group represented by the above formula (DA-a), or the diamine-derived structural unit having a divalent organic group derived from other diamines as exemplified in polymer (A), may be 100 mol%, 95 mol% or less, or 90 mol% or less, relative to 100 mol% of the total diamine-derived structural units contained in the polyimide precursor in polymer (B).
[0039] The structural units derived from the tetracarboxylic acid derivative in the polyimide precursor of polymer (B) may include structural units derived from the tetracarboxylic acid derivative other than the tetravalent organic group represented by formulas (X-3) to (X-5) above. Examples of structural units derived from the tetracarboxylic acid derivative other than the tetravalent organic group represented by formulas (X-3) to (X-5) above include structural units derived from other tetracarboxylic acid derivatives exemplified in polymer (A) and structural units derived from tetracarboxylic acid derivatives having a tetravalent organic group represented by formula (X-2) above.
[0040] In the polyimide precursor of the polymer (B) described above, it is preferable that the content ratio of a structural unit derived from a tetracarboxylic acid derivative having a tetravalent organic group represented by formula (X-3) (hereinafter also referred to as "structural unit I") and a structural unit derived from a tetracarboxylic acid derivative having a tetravalent organic group represented by any of the formulas (X-4) to (X-5) (hereinafter also referred to as "structural unit II") is 90 / 10 to 20 / 80 in terms of the molar ratio of [structural unit I / structural unit II].
[0041] In the polyimide precursor of polymer (B), the combined content of structural unit I and structural unit II is preferably 40 to 100 mol% relative to 100 mol% of the total structural units derived from the tetracarboxylic acid derivative in the polyimide precursor of polymer (B). Structural units derived from the tetracarboxylic acid derivative other than the tetravalent organic group represented by formulas (X-3) to (X-5) may be 60 mol% or less relative to 100 mol% of the total structural units derived from the tetracarboxylic acid derivative in the polyimide precursor of polymer (B).
[0042] In one embodiment, the liquid crystal alignment agent of the present invention may have a content ratio of polymer (A) to polymer (B) of 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20 in terms of the mass ratio of [polymer (A) / polymer (B)].
[0043] <Production of Polyimide Precursor or Polyimide>In the polymer (A) contained in the liquid crystal aligning agent of the present invention, the polyamic acid in which at least one of R in the above formula (A1) is a hydrogen atom can be produced, for example, by the following method. The same applies to the polymer (B).
[0044] By reacting a tetracarboxylic dianhydride component and a diamine component, a polymer having an amic acid structure (polyamic acid) is obtained. When the polyamic acid has a structure represented by the above formula (A1), for example, as the diamine component, a diamine having a structure of -N(Z)-Y １ -N(Z)- (Y １ and Z are defined as above.) is used, and as the tetracarboxylic acid derivative component, X １ (X １ is defined as above.) is used. For the detailed synthesis method of the polyimide precursor and polyimide, reference can be made to, for example, WO2015 / 012368.
[0045] When producing the polyimide precursor and polyimide in the present invention, a terminal-capped polymer may be produced using an appropriate terminal capping agent together with a tetracarboxylic acid component containing a tetracarboxylic dianhydride or its derivative, and a diamine component containing a diamine. The terminal-capped polymer has the effects of improving the film hardness of the liquid crystal alignment film obtained by the coating film and improving the adhesion between the sealant and the liquid crystal alignment film.
[0046] Examples of the terminals of the polyimide precursor and polyimide in the present invention include an amino group, a carboxy group, an acid anhydride group, or a group derived from a terminal capping agent described later. The amino group, carboxy group, and acid anhydride group can be obtained by a normal condensation reaction or by capping the terminal using the following terminal capping agent.
[0047] Examples of end-capturing agents include acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, succinic anhydride, 1,2-cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; and chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride. Compounds; 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; and isocyanates having unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.
[0048] The proportion of end-capturing agent used is preferably 0.01 to 20 moles, and more preferably 0.01 to 10 moles, per 100 moles of the total diamine components used.
[0049] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, and 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) measured by GPC, is preferably 15 or less, and more preferably 10 or less. Being within this molecular weight range ensures good liquid crystal alignment of the liquid crystal display element. <Solution viscosity and molecular weight of polymer> The polymer (A) used in the present invention is preferably, from the viewpoint of workability, has a solution viscosity of, for example, 10 to 1,000 mPa·s when it is prepared as a solution with a concentration of 10 to 15% by mass. The solution viscosity (mPa·s) of the above polymer was measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10 to 15% by mass, prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).
[0050] The weight-average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and 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) measured by GPC in terms of polystyrene, is preferably 15 or less, and more preferably 10 or less. Being within this molecular weight range ensures good orientation and stability of the liquid crystal display element.
[0051] The liquid crystal alignment agent of the present invention may contain polymers other than polymer (A) and polymer (B). Specific examples of other polymers include polymers selected from the group consisting of polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-maleic anhydride) copolymer, poly(isobutylene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley Co., Ltd.), and GSM301 (manufactured by Gifu Ceratek Manufacturing Co., Ltd.). Specific examples of poly(isobutylene-maleic anhydride) copolymers include Isoban-600 (manufactured by Kuraray Co., Ltd.). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland Co., Ltd.).
[0052] Other polymers may be used individually or in combination of two or more. The content ratio of the other polymers is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass, per 100 parts by mass of polymer components contained in the liquid crystal alignment agent.
[0053] In this specification, the polymer component refers to the polymer (A), polymer (B), and other polymers other than polymer (A) and polymer (B) that are contained in the liquid crystal alignment agent as needed. If the only polymers contained in the liquid crystal alignment agent are polymer (A) and polymer (B), the polymer component refers to polymer (A) and polymer (B).
[0054] <Liquid Crystal Alignment Agent> The liquid crystal alignment agent of the present invention is used to produce a liquid crystal alignment film, and from the viewpoint of forming a uniform thin film, it takes the form of a coating solution. In the liquid crystal alignment agent of the present invention, it is preferable that it is a coating solution containing the polymer component described above and a solvent.
[0055] The content (concentration) of the polymer component contained in the liquid crystal alignment agent of the present invention can be appropriately changed depending on the desired thickness of the coating film to be formed. However, from the viewpoint of forming a uniform and defect-free coating film, it is preferable to have 1% by mass or more relative to the total amount of the liquid crystal alignment agent, and from the viewpoint of the storage stability of the solution, it is preferable to have 10% by mass or less.
[0056] From the viewpoint of suitably obtaining the effects of this disclosure, the content ratio of polymer components in the liquid crystal alignment agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50 parts by mass or more, based on 100 parts by mass of the total polymers contained in the liquid crystal alignment agent. When the liquid crystal alignment agent contains other polymers, the content ratio of polymer components is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass, based on 100 parts by mass of polymer components contained in the liquid crystal alignment agent.
[0057] The solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer components. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethyl Examples include lupropanamide, 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-(3-methoxypropyl)-2-pyrrolidone, N-(2-ethoxyethyl)-2-pyrrolidone, N-(4-methoxybutyl)-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone (collectively referred to as "good solvents"). Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-diethylacetamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone are preferred. The content of good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.
[0058] Furthermore, it is preferable to use a mixed solvent in which the solvent contained in the liquid crystal alignment agent is combined with a solvent (also called a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of poor solvents used in combination are listed below, but are not limited to these.
[0059] For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol Examples include 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, and diisobutyl ketone (2,6-dimethyl-4-heptanone). The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent are appropriately selected depending on the coating apparatus, coating conditions, and coating environment of the liquid crystal alignment agent.
[0060] Among these, diisobutylcarbinol, 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.
[0061] Preferred solvent combinations of good and poor solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, and N-methyl-2-pyrrolidone and γ- Examples include butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylcarbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; and N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether.
[0062] The liquid crystal alignment agent of the present invention may additionally contain components other than polymer components and solvents (hereinafter also referred to as additive components). Examples of such additive components include compounds for increasing the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds), adhesion aids 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, dielectrics and conductive materials for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film, or imidization accelerators for promoting imidization.
[0063] Examples of the above crosslinkable compounds include at least one crosslinkable compound selected from the group consisting of a crosslinkable compound (c-1) having at least one substituent selected from epoxy groups, oxetanyl groups, oxazoline structures, cyclocarbonate groups, blocked isocyanate groups, hydroxyl groups, and alkoxy groups, and a crosslinkable compound (c-2) having a polymerizable unsaturated group. Preferred specific examples of the above crosslinkable compounds (c-1) and (c-2) include the following compounds. Compounds containing epoxy groups 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, glycerin diglycidyl ether, dibromo neopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as Epicote 828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as Epicote 807 (manufactured by Mitsubishi Chemical Corporation), and hydrogenated bisphenol F epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation). Compounds in which a tertiary nitrogen atom is bonded to an aromatic carbon atom, such as phenol A type epoxy resin, biphenyl skeleton-containing epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), (o,m,p-) cresol novolac type epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), tetrakis(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, and N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane;N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl ) Compounds in which a tertiary nitrogen atom is bonded to an aliphatic carbon atom, such as cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, 1,3,5-tris(N,N-diglycidylaminomethyl)benzene, isocyanurate compounds such as triglycidyl isocyanurate (manufactured by Nissan Chemical Corporation), compounds described in paragraph
[0037] of Japanese Patent Publication No. 10-338880, and compounds described in WO2017 / 170483, etc. Compounds having an oxetanyl group include 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Aronoxetane OXT-121 (XDO)), bis[2-(3-oxetanyl)butyl] ether (Aronoxetane OXT-221 (DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), and compounds having two or more oxetanyl groups as described in paragraphs
[0170] to
[0175] of WO2011 / 132751; Compounds having an oxazoline structure include compounds such as 2,2'-bis(2-oxazoline) and 2,2'-bis(4-methyl-2-oxazoline), polymers and oligomers having an oxazoline group such as Epocross (trade name, manufactured by Nippon Shokubai Co., Ltd.), and compounds described in paragraph
[0115] of Japanese Patent Publication No. 2007-286597;Examples of compounds having a cyclocarbonate group include N,N,N',N'-tetra[(2-oxo-1,3-dioxolan-4-yl)methyl]-4,4'-diaminodiphenylmethane, N,N',-di[(2-oxo-1,3-dioxolan-4-yl)methyl]-1,3-phenylenediamine, and the compounds described in paragraphs
[0025] to
[0030] and
[0032] of WO2011 / 155577; Examples of compounds having blocked isocyanate groups include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.), compounds having two or more protected isocyanate groups as described in paragraphs
[0046] to
[0047] of Japanese Patent Publication No. 2014-224978, compounds having three or more protected isocyanate groups as described in paragraphs
[0119] to
[0120] of WO2015 / 141598, etc. Compounds having a hydroxyl group and / or alkoxy group include N,N,N',N'-tetrakis(2-hydroxyethyl)adipoamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, compounds described in WO2015 / 072554 and paragraph
[0058] of Japanese Patent Publication No. 2016-118753, compounds described in Japanese Patent Publication No. 2016-200798, compounds described in WO2010 / 074269, etc.Examples of crosslinkable compounds having polymerizable unsaturated groups include glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-compound mixture), glycerin tris(meth)acrylate, glycerol 1,3-diglycerolate di(meth)acrylate, pentaerythritol tri(meth)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, etc.
[0064] The above compounds are examples of crosslinkable compounds and are not limited thereto. For example, other components disclosed on pages 53
[0105] to 55
[0116] of WO2015 / 060357 can be cited. Furthermore, two or more crosslinkable compounds may be combined.
[0065] When a crosslinkable compound is used, the content of the crosslinkable compound in the liquid crystal alignment agent is preferably 0.5 to 20 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.
[0066] Examples of the adhesion aids mentioned above include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, and N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-3-triethoxysilylpropyltriethylenetetramine, N-3-trimethoxysilylpropyltriethylenetetramine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3-aminopropyltrimethoxysilane, N- Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxy Examples of silane coupling agents include silane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane.
[0067] When an adhesion aid is used, the content of the adhesion aid in the liquid crystal alignment agent is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.
[0068] Examples of dielectric or conductive materials include monoamines having nitrogen-containing aromatic heterocycles, such as 3-picolylamine.
[0069] When a dielectric or conductive material is used, the content of the dielectric or conductive material in the liquid crystal alignment agent is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. As a compound for promoting the above imidation, a compound having a basic site (e.g., a primary amino group, an aliphatic heterocycle (e.g., a pyrrolidine skeleton), an aromatic heterocycle (e.g., an imidazole ring, an indole ring), or a guanidino group, etc.) is preferred (however, the above crosslinking compound and compounds for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film are excluded), or a compound that generates the above basic site during firing. More preferably, a compound that generates the above basic site during firing is preferred, and a preferred specific example is an amino acid in which some or all of the basic site of the amino acid is protected. As a protecting group for the basic site of the above amino acid, a carbamate protecting group such as a Boc group is recommended. Specific examples of the above amino acids include glycine, alanine, cysteine, methionine, asparagine, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, and ornithine. More preferred specific examples of compounds for promoting imidation include N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine, or N-α-(tert-butoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine. The content of the above imidation-promoting compound contained in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 5 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.
[0070] (Liquid crystal alignment film) The liquid crystal alignment film of the present invention is formed using the liquid crystal alignment agent of the present invention described above. A method for manufacturing the liquid crystal alignment film of the present invention includes, for example, applying the liquid crystal alignment agent described above to a substrate, firing it, and irradiating the resulting film with polarized radiation.
[0071] A preferred embodiment of the method for manufacturing a liquid crystal alignment film of the present invention includes, for example, a step of coating the above-mentioned liquid crystal alignment agent onto a substrate (step (1)), a step of firing the coated liquid crystal alignment agent (step (2)), and optionally, a step of performing an alignment treatment on the film obtained in step (2) (step (3)). <Step (1)> The substrate on which the liquid crystal alignment agent used in the present invention is coated is not particularly limited as long as it is a highly transparent substrate, and glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates and other plastic substrates can be used. In this case, it is preferable to use a substrate on which ITO (Indium Tin Oxide) electrodes for driving the liquid crystal are formed, from the viewpoint of simplifying the process. In addition, in the case of a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one side of the substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrodes. Furthermore, when manufacturing IPS-driven or FFS-driven liquid crystal display elements, a substrate is used that has electrodes made of a comb-shaped patterned transparent conductive film or metal film, and a counter substrate is used that does not have electrodes.
[0072] Methods for coating a substrate with a liquid crystal alignment agent and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray printing. Among these, the inkjet method for coating and forming a film is particularly suitable. <Step (2)> Step (2) is a step of firing the liquid crystal alignment agent coated on the substrate to form a film. After coating the substrate with the liquid crystal alignment agent, the solvent can be evaporated or the amic acid or amic acid ester in the polymer can be thermally imidized using a heating means such as a hot plate, a hot air circulation oven, or an IR (infrared) oven. The drying and firing steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and may be performed multiple times. The temperature at which the solvent of the liquid crystal alignment agent is evaporated can be, for example, 40 to 180°C as the temperature of the heating means, but from the viewpoint of shortening the process, it may be performed at 40 to 150°C. The firing time is not particularly limited, but for example it is 1 to 10 minutes, preferably 1 to 5 minutes. If, in addition to the step of evaporating the solvent, a step of thermal imidation of the amic acid in the polymer is performed, then after the step of evaporating the solvent, a further firing step can be performed at a temperature range of, for example, 150 to 300°C, preferably 150 to 250°C, using a heating means. The firing time in the thermal imidation step is not particularly limited, but is for example 5 to 40 minutes, preferably 5 to 30 minutes.
[0073] If the film-like material after firing is too thin, the reliability of the liquid crystal display element may decrease, so a thickness of 5 to 300 nm is preferred, and 10 to 200 nm is more preferred. <Step (3)> Step (3) is a step of orientation treatment on the film obtained in step (2). As a method of orientation treatment for the liquid crystal alignment film, a rubbing method or a photo-alignment method can be used, but the photo-alignment method is preferred. As a photo-alignment method, the surface of the above-mentioned film-like material is irradiated with radiation polarized in a certain direction, and if necessary, heat treatment is performed to impart liquid crystal alignment properties (also called liquid crystal alignment ability). As radiation, ultraviolet light or visible light having a wavelength of 100 to 800 nm can be used. Among these, ultraviolet light having a wavelength of 100 to 400 nm is preferred, and more preferably 200 to 400 nm.
[0074] The radiation doses mentioned above range from 1 to 400 mJ / cm². ２ Preferably, 10 to 300 mJ / cm ２ More preferably, 50 to 250 mJ / cm ２ That is even more preferable.
[0075] As a light source for illumination, for example, low-pressure mercury lamps, high-pressure mercury lamps, deep UV lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, mercury xenon lamps, excimer lasers (e.g., KrF excimer lasers), fluorescent lamps, LED lamps, halogen lamps (e.g., sodium lamps), microwave-excited electrodeless lamps, etc., can be used.
[0076] Furthermore, when polarized light is used as the irradiating light, a higher extinction ratio of the polarized light can impart greater anisotropy. For example, in the case of ultraviolet light, a extinction ratio of polarized ultraviolet light of 10:1 or higher is more preferable, and 20:1 or higher is even more preferable.
[0077] Furthermore, when irradiating with radiation, the substrate having the above-mentioned film-like material may be irradiated while being heated at 50 to 250°C in order to improve the liquid crystal alignment properties. The liquid crystal alignment film produced in this manner can stably align liquid crystal molecules in a certain direction.
[0078] Furthermore, using the method described above, the liquid crystal alignment film irradiated with polarized radiation can be brought into contact with these materials using a solvent, or the irradiated liquid crystal alignment film can be heat-treated.
[0079] The heat treatment of the irradiated coating film is preferably performed at 50 to 300°C for 1 to 30 minutes, and more preferably at 120 to 250°C for 1 to 30 minutes.
[0080] (Liquid Crystal Display Element) The liquid crystal display element of the present invention has the liquid crystal alignment film of the present invention. The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for transverse electric field type liquid crystal display elements such as the IPS method and the FFS method, from the viewpoint of obtaining high liquid crystal alignment properties, and is particularly useful as a liquid crystal alignment film for FFS type liquid crystal display elements.
[0081] A liquid crystal display element can be manufactured by first obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention, then fabricating a liquid crystal cell by a known method, and finally arranging liquid crystal within the liquid crystal cell. Specifically, the following two methods can be mentioned.
[0082] The first method involves first arranging two substrates opposite each other with a gap (cell gap) in between so that their respective liquid crystal alignment films face each other. Next, the periphery of the two substrates is bonded together using a sealant, and the liquid crystal composition is injected and filled into the cell gaps partitioned by the substrate surface and the sealant, making contact with the film surface, and then the injection holes are sealed.
[0083] The second method is called the ODF (One Drop Fill) method. In this method, a UV-curable sealant is applied to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed, and then liquid crystal composition is dropped onto several predetermined locations on the surface of the liquid crystal alignment film. After that, the other substrate is bonded together so that the liquid crystal alignment films face each other, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant.
[0084] In either the first or second method, it is desirable to further remove the flow orientation during liquid crystal filling by heating the liquid crystal composition to a temperature at which it forms an isotropic phase, and then slowly cooling it to room temperature.
[0085] When a rubbing treatment is performed on the coating film, the two substrates are positioned opposite each other so that the rubbing directions in each coating film are at a predetermined angle to each other, for example, orthogonal or antiparallel. Similarly, when a photo-alignment treatment is performed, the substrates are positioned opposite each other so that their orientation directions are at a predetermined angle to each other, for example, orthogonal or antiparallel.
[0086] As a sealant, for example, an epoxy resin containing aluminum oxide spheres as a curing agent and spacer can be used. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.
[0087] The liquid crystal composition is not particularly limited and is a composition containing at least one liquid crystal compound (liquid crystal molecule). Either a liquid crystal composition with positive dielectric anisotropy (also called a positive-type liquid crystal composition or positive-type liquid crystal) or a liquid crystal composition with negative dielectric anisotropy (also called a negative-type liquid crystal composition or negative-type liquid crystal) may be used, but a negative-type liquid crystal material is preferred.
[0088] The above liquid crystal composition may contain liquid crystal compounds having a fluorine atom, a hydroxyl group, an amino group, a fluorine atom-containing group (e.g., a trifluoromethyl group), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, and may also contain compounds having two or more rigid sites (mesogenic skeletons) that exhibit liquid crystallinity within the molecule (for example, a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by alkyl groups). The liquid crystal composition may be a liquid crystal composition exhibiting a nematic phase, a liquid crystal composition exhibiting a smectic phase, or a liquid crystal composition exhibiting a cholesteric phase.
[0089] Furthermore, the above liquid crystal composition may contain additional additives from the viewpoint of improving liquid crystal alignment. Examples of such additives include photopolymerizable monomers such as compounds having polymerizable groups as described below, optically active compounds (e.g., S-811 from Merck), antioxidants, ultraviolet absorbers, dyes, defoamers, polymerization initiators, or polymerization inhibitors.
[0090] Examples of positive-type LCDs include the ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081, all manufactured by Merck.
[0091] Examples of negative-type liquid crystal displays include Merck's MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, or MLC-7029; and DIC's NA-1559.
[0092] In addition, in PSA mode, Merck's MLC-3023 is an example of a liquid crystal containing a polymerizable compound.
[0093] Next, the polarizing plates are installed. Specifically, a pair of polarizing plates are attached to the sides of the two substrates opposite to the liquid crystal layer. Examples of polarizing plates include polarizing plates made by sandwiching a polarizing film called an "H film," which is made by stretching and oriented polyvinyl alcohol while absorbing iodine, between cellulose acetate protective films, or polarizing plates made of the H film itself.
[0094] The present invention will be further described in detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring each physical property are as follows: (Organic solvents) NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: Butyl cellosolve (Tetracarboxylic acid dianhydrides) TC-1 to TC-8: Compounds represented by the following formulas (TC-1) to (TC-8), respectively (Diamines) DA-1 to DA-11: Compounds represented by the following formulas (DA-1) to (DA-11), respectively. (Additives) AD-1 to AD-2: Compounds represented by the following formulas (AD-1) to (AD-2), respectively.
[0095] <Viscosity Measurement> Viscosity was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, using a cone rotor TE-1 (1°34', R24) at a temperature of 25°C.
[0096] [Synthesis of Polymers] <Synthesis Example 1> DA-1 (18.9 g, 66.0 mmol) and NMP (170 g) were added to a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. After cooling to 15°C, TC-1 (14.2 g, 63.4 mmol) and NMP (69.6 g) were added, and the mixture was stirred at 40°C for 3 hours to obtain a solution of polyamic acid (A-1) with a solid content of 12% by mass (viscosity: 550 mPa·s).
[0097] <Synthesis Example 2> In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-2 (1.62 g, 15.0 mmol), DA-3 (5.49 g, 22.5 mmol), DA-4 (7.20 g, 22.5 mmol), DA-5 (5.97 g, 15.0 mmol), TC-1 (15.9 g, 71.1 mmol), and NMP (264 g) were added and stirred at 40°C for 20 hours to obtain a solution of polyamic acid (A-2) with a solid content of 12% by mass (viscosity: 400 mPa·s).
[0098] <Synthesis Example 3> DA-1 (20.6 g, 72.0 mmol) and NMP (185 g) were added to a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-2 (15.1 g, 69.5 mmol) and NMP (76.8 g) were added, and the mixture was stirred at 50°C for 15 hours to obtain a solution of polyamic acid (A-3) with a solid content of 12% by mass (viscosity: 530 mPa·s).
[0099] <Synthesis Example 4> DA-6 (2.29 g, 5.50 mmol) and NMP (16.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-2 (1.15 g, 5.27 mmol) and NMP (8.10 g) were added, and the mixture was stirred at 50°C for 18 hours to obtain a solution of polyamic acid (A-4) with a solid content of 12% by mass (viscosity: 241 mPa·s).
[0100] <Synthesis Example 5> DA-6 (3.00 g, 7.20 mmol), DA-7 (0.710 g, 1.79 mmol), and NMP (33.4 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-2 (1.87 g, 8.57 mmol) and NMP (7.50 g) were added, and the mixture was stirred at 50°C for 18 hours to obtain a solution of polyamic acid (A-5) with a solid content of 12% by mass (viscosity: 224 mPa·s).
[0101] <Synthesis Example 6> DA-8 (0.800 g, 4.01 mmol), DA-3 (0.980 g, 4.01 mmol), and NMP (10.9 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.160 g, 0.816 mmol) and NMP (6.50 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. After cooling to room temperature (25°C), TC-4 (2.08 g, 6.79 mmol) and NMP (5.40 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-6) with a solid content of 15% by mass (viscosity: 282 mPa·s).
[0102] <Synthesis Example 7> DA-8 (1.30 g, 6.52 mmol), DA-3 (1.59 g, 6.51 mmol), and NMP (23.3 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.637 g, 3.25 mmol) and NMP (5.20 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. After cooling to room temperature (25°C), TC-4 (2.73 g, 8.92 mmol) and NMP (6.90 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-7) with a solid content of 15% by mass (viscosity: 298 mPa·s).
[0103] <Synthesis Example 8> DA-8 (1.40 g, 7.03 mmol), DA-3 (1.71 g, 7.00 mmol), and NMP (25.1 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (2.14 g, 6.99 mmol) and NMP (4.60 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-3 (1.19 g, 6.07 mmol) and NMP (6.40 g) were added, and the mixture was stirred at room temperature (25°C) for 18 hours to obtain a solution of polyamic acid (A-8) with a solid content of 15% by mass (viscosity: 281 mPa·s).
[0104] <Synthesis Example 9> DA-8 (1.30 g, 6.52 mmol), DA-3 (1.59 g, 6.51 mmol), and NMP (21.1 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (1.00 g, 3.27 mmol) and NMP (4.80 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-3 (1.63 g, 8.29 mmol) and NMP (5.20 g) were added, and the mixture was stirred at room temperature (25°C) for 18 hours to obtain a solution of polyamic acid (A-9) with a solid content of 15% by mass (viscosity: 287 mPa·s).
[0105] <Synthesis Example 10> DA-8 (0.890 g, 4.47 mmol), DA-3 (1.09 g, 4.46 mmol), and NMP (11.2 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (1.36 g, 4.44 mmol) and NMP (4.00 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-5 (0.800 g, 4.04 mmol) and NMP (8.20 g) were added, and the mixture was stirred at 50°C for 18 hours to obtain a solution of polyamic acid (A-10) with a solid content of 15% by mass (viscosity: 244 mPa·s).
[0106] <Synthesis Example 11> DA-9 (0.510 g, 1.21 mmol), DA-8 (0.480 g, 2.41 mmol), DA-3 (1.03 g, 4.22 mmol), DA-10 (0.830 g, 4.19 mmol), and NMP (20.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.240 g, 1.22 mmol) and NMP (6.90 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.17 g, 10.4 mmol) and NMP (7.70 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-11) with a solid content of 15% by mass (viscosity: 299 mPa·s).
[0107] <Synthesis Example 12> DA-9 (1.39 g, 3.30 mmol), DA-10 (1.53 g, 7.72 mmol), and NMP (21.4 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.220 g, 1.12 mmol) and NMP (6.80 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (2.94 g, 9.60 mmol) and NMP (6.20 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-12) with a solid content of 15% by mass (viscosity: 410 mPa·s).
[0108] <Synthesis Example 13> DA-11 (1.54 g, 3.90 mmol), DA-10 (1.80 g, 9.10 mmol), and NMP (24.5 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.260 g, 1.33 mmol) and NMP (7.90 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.43 g, 11.2 mmol) and NMP (7.40 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-13) with a solid content of 15% by mass (viscosity: 345 mPa·s).
[0109] <Synthesis Example 14> DA-3 (0.977 g, 4.00 mmol), DA-8 (0.797 g, 4.00 mmol), and NMP (10.1 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-6 (1.50 g, 6.00 mmol) and NMP (8.50 g) were added, and the mixture was stirred at 50°C for 2 hours. After cooling to room temperature (25°C), TC-7 (0.494 g, 1.68 mmol) and NMP (2.80 g) were added, and the mixture was stirred at 50°C for 15 hours to obtain a solution of polyamic acid (A-14) with a solid content of 15% by mass (viscosity: 321 mPa·s).
[0110] <Synthesis Example 15> DA-8 (1.30 g, 6.52 mmol), DA-3 (1.59 g, 6.51 mmol), and NMP (25.9 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (1.99 g, 6.50 mmol) and NMP (4.00 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-6 (1.49 g, 5.95 mmol) and NMP (6.10 g) were added, and the mixture was stirred at 50°C for 18 hours to obtain a solution of polyamic acid (A-15) with a solid content of 15% by mass (viscosity: 351 mPa·s).
[0111] <Synthesis Example 16> DA-8 (0.860 g, 4.32 mmol), DA-3 (1.05 g, 4.30 mmol), and NMP (15.4 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (1.32 g, 4.30 mmol) and NMP (2.80 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-8 (0.860 g, 3.84 mmol) and NMP (4.90 g) were added, and the mixture was stirred at 50°C for 18 hours to obtain a solution of polyamic acid (A-16) with a solid content of 15% by mass (viscosity: 264 mPa·s).
[0112] <Synthesis Example 17> DA-8 (1.25 g, 6.27 mmol), DA-3 (1.53 g, 6.26 mmol), and NMP (24.9 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (1.91 g, 6.24 mmol) and NMP (3.80 g) were added, and the mixture was stirred at 40°C for 4 hours. After cooling to room temperature (25°C), TC-7 (1.62 g, 5.50 mmol) and NMP (6.90 g) were added, and the mixture was stirred at 70°C for 18 hours to obtain a solution of polyamic acid (A-17) with a solid content of 15% by mass (viscosity: 348 mPa·s).
[0113] <Synthesis Example 18> DA-8 (1.20 g, 6.02 mmol), DA-3 (1.45 g, 5.94 mmol), and NMP (17.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-4 (3.50 g, 11.4 mmol) and NMP (17.1 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-18) with a solid content of 15% by mass (viscosity: 308 mPa·s).
[0114] <Synthesis Example 19> DA-8 (1.67 g, 8.40 mmol), DA-3 (2.05 g, 8.40 mmol), and NMP (27.3 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (2.73 g, 13.9 mmol) and NMP (9.30 g) were added, and the mixture was stirred at room temperature (25°C) for 18 hours to obtain a solution of polyamic acid (A-19) with a solid content of 15% by mass (viscosity: 317 mPa·s).
[0115] <Synthesis Example 20> DA-8 (1.00 g, 5.02 mmol), DA-3 (1.22 g, 4.99 mmol), and NMP (8.90 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-5 (1.91 g, 9.64 mmol) and NMP (14.5 g) were added, and the mixture was stirred at 70°C for 18 hours to obtain a solution of polyamic acid (A-20) with a solid content of 15% by mass (viscosity: 288 mPa·s).
[0116] <Synthesis Example 21> DA-3 (1.95 g, 7.98 mmol) and NMP (12.0 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.780 g, 3.98 mmol) and NMP (4.80 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (1.04 g, 3.40 mmol) and NMP (4.60 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-21) with a solid content of 15% by mass (viscosity: 286 mPa·s).
[0117] <Synthesis Example 22> DA-10 (2.58 g, 13.0 mmol) and NMP (18.9 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.260 g, 1.33 mmol) and NMP (6.60 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.49 g, 11.4 mmol) and NMP (10.3 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-22) with a solid content of 15% by mass (viscosity: 334 mPa·s).
[0118] <Synthesis Example 23> DA-8 (1.91 g, 9.59 mmol), DA-10 (0.480 g, 2.42 mmol), and NMP (17.5 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.240 g, 1.22 mmol) and NMP (6.10 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.14 g, 10.3 mmol) and NMP (9.10 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-23) with a solid content of 15% by mass (viscosity: 315 mPa·s).
[0119] <Synthesis Example 24> DA-9 (1.52 g, 3.61 mmol), DA-2 (0.910 g, 8.42 mmol), and NMP (17.8 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.240 g, 1.22 mmol) and NMP (6.20 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.19 g, 10.4 mmol) and NMP (9.20 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-24) with a solid content of 15% by mass (viscosity: 419 mPa·s).
[0120] <Synthesis Example 25> DA-9 (0.550 g, 1.30 mmol), DA-2 (0.630 g, 5.83 mmol), DA-10 (1.16 g, 5.85 mmol), and NMP (17.2 g) were added to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature (25°C) while supplying nitrogen. Then, TC-3 (0.260 g, 1.33 mmol) and NMP (6.20 g) were added, and the mixture was stirred at room temperature (25°C) for 2 hours. Then, TC-4 (3.48 g, 11.4 mmol) and NMP (11.1 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a solution of polyamic acid (A-25) with a solid content of 15% by mass (viscosity: 312 mPa·s).
[0121] Table 1 shows the types and amounts of tetracarboxylic acid and diamine components used in the above synthesis examples 1 to 25. In Table 1, the values for tetracarboxylic acid and diamine components represent the proportion (moles) of each compound used relative to 100 moles of the total amount of diamine components used in the synthesis of each polyamic acid. In Table 1, the specific tetracarboxylic acid TB1 is represented by X in the above formula (B1). １’ It is a compound that can constitute part of the above formula (B2). The specific tetracarboxylic acid TB2 is X ２’ It is a compound that can constitute part of the above formula (A1). The specific tetracarboxylic acid TA is X １ It is a compound that can constitute part of the above formula (A1). Specific diamine DS is a compound having the structure of formula (DB-1) above. Specific diamine DA is a compound having the Y in formula (A1) above.１ It is a compound that can constitute the portion of
[0122]
[0123] [Preparation of Liquid Crystal Alignment Agent] <Example 1> To a solution (0.88 g) of the polyamic acid (A-1) obtained in Synthesis Example 1, a solution (2.10 g) of the polyamic acid (A-6) obtained in Synthesis Example 6, NMP (0.86 g), GBL (3.94 g), BCS (3.60 g), AD-1 (1 mass% GBL solution, 0.42 g), and AD-2 (10 mass% NMP solution, 0.21 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain the liquid crystal alignment agent (AL-1) of the present invention.
[0124] <Examples 2 to 26 and Comparative Examples 1 to 10> The liquid crystal alignment agents (AL-2) to (AL-24) of Examples 2 to 24 and the liquid crystal alignment agents (AL-C1) to (AL-C10) of Comparative Examples 1 to 10 of the present invention were obtained by operating in the same manner as in Example 1 above, except that the types and amounts of the polymer solution, solvent, and additives used were changed as shown in Table 2.
[0125]
[0126] In Table 2, the mass ratios of polyamic acid 1, polyamic acid 2, additive 1, and additive 2 represent the ratios (parts by mass) of each polyamic acid and each additive to a total of 100 parts by mass of the polyamic acid component.
[0127] <Evaluation of Reworkability> The liquid crystal alignment agent obtained above was applied to a 3cm x 4cm rectangular glass substrate with a thickness of 1.1mm using the spin-coating method. After drying on a hot plate at 80°C for 2 minutes, it was baked in a hot air circulating oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film thickness of 100nm. Subsequently, the substrate with the liquid crystal alignment film was immersed in a rework agent (PK-SFR7500, manufactured by Parker Corporation) heated to 45°C for 60 seconds for development, and then washed with ultrapure water for 30 seconds. After that, it was air-blown and the remaining film thickness was measured. Reworkability was evaluated by the ratio of film thickness before and after treatment with the rework agent. Specifically, the residual film percentage was calculated using the following formula, and it was evaluated as "A" if the residual film percentage was 40% or less, and as "C" if the residual film percentage was greater than 40%. Residual film percentage (%) = (Film thickness after treatment with rework agent / Film thickness before treatment with rework agent) × 100
[0128] <Evaluation of the film's hygroscopic properties> The liquid crystal alignment agent obtained above was applied to a 10 cm x 10 cm square ITO substrate with a thickness of 1.1 mm using a spin-coating method. After drying on a hot plate at 80°C for 2 minutes, it was baked in a hot air circulating oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film with a thickness of 200 nm. Subsequently, this liquid crystal alignment film was stored in a constant humidity and temperature chamber at 85°C and 85% relative humidity for 18 hours, and then removed from the chamber and left at room temperature and 45% relative humidity for 5 hours. The liquid crystal alignment film was cut and peeled off from the ITO substrate using a knife, and the mass of the obtained peeled film was weighed using a precision balance. Subsequently, the peeled film was dried in a hot air circulating oven at 100°C for 20 minutes, and its mass was weighed again using a precision balance to measure the change in mass before and after drying. As an evaluation criterion, a grade of "A" was assigned if the decrease in mass of the peeled film after drying was 7.90% or less compared to the mass of the peeled film before drying, and a grade of "C" was assigned if the decrease in mass was greater than 7.90%.
[0129] <Fabrication of FFS-driven liquid crystal cell> A liquid crystal cell with an FFS mode liquid crystal display element configuration was fabricated. First, a substrate with electrodes was prepared. The substrate was a 30 mm x 50 mm rectangular glass substrate with a thickness of 0.7 mm. A patterned ITO electrode, which functions as a common electrode, was formed over the entire surface as the first layer. On top of the first layer common electrode, a SiN (silicon nitride) film deposited by CVD (chemical vapor deposition) was formed as the second layer. The thickness of the second SiN film was 300 nm, and it was a thickness that functioned as an interlayer insulating film. On top of the second SiN film, a comb-shaped pixel electrode formed by patterning the ITO film was arranged as the third layer, forming two pixels, the first and second pixels, with each pixel measuring 10 mm vertically and 5 mm horizontally. This electrode-equipped substrate had a structure in which the first layer common electrode and the third layer pixel electrode were insulated by the second layer SiN film. The third layer of pixel electrodes had a comb-like shape, with the central portion bent at an internal angle of 160°, and multiple electrode lines with a width of 3 μm arranged parallel to each other at intervals of 6 μm. Each pixel was formed by multiple electrode lines and had a first region and a second region separated by a line connecting the bends.
[0130] Next, the liquid crystal alignment agent obtained above was filtered through a filter with a pore size of 1.0 μm, and then applied by spin coating to the electrode-equipped substrate (hereinafter referred to as the electrode substrate) and a glass substrate having a columnar spacer with a height of 4 μm and an ITO film deposited on its back surface (hereinafter referred to as the opposing substrate). After drying on a hot plate at 80°C for 2 minutes, the coating was baked in a hot air circulating oven at 230°C for 20 minutes to form a coating with a thickness of 60 nm. The coatings using the liquid crystal alignment agents of Examples 1-5, Examples 9-26, Comparative Examples 1-7, and Comparative Examples 9-10 were subjected to rubbing alignment treatment with a rayon cloth (Hyperflex, HY-5318) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, travel speed: 20 mm / sec, pressing length: 0.4 mm). Subsequently, the substrates were cleaned by ultrasonic irradiation in pure water for 1 minute, water droplets were removed by air blowing, and then dried at 80°C for 10 minutes to obtain substrates with liquid crystal alignment films. The coated surfaces of the liquid crystal alignment agents used in Examples 6-8 and Comparative Example 8 were irradiated with polarized ultraviolet light through a 254 nm bandpass filter and polarizer at an exposure dose of 300 mJ / cm2, and then baked in an IR oven at 230°C for 30 minutes to perform photoalignment treatment and obtain substrates with liquid crystal alignment films. The liquid crystal alignment films formed on the electrode substrates were oriented so that the direction dividing the inner angle of the pixel bending portion was parallel to the orientation direction of the liquid crystals, and the liquid crystal alignment films formed on the opposing substrates were oriented so that the orientation direction of the liquid crystals on the electrode substrate matched the orientation direction of the liquid crystals on the opposing substrate when fabricating the liquid crystal cells. The two substrates described above were used as a pair. A sealant (Mitsui Chemicals XN-1500T) was printed onto the substrate using a dispenser, and the other substrate was bonded to it so that the orientation direction of the liquid crystal alignment films was 0° and facing each other. The bonded substrates were then pressed together and heated in a 150°C hot air circulating oven for 60 minutes to cure the sealant and create an empty cell. Negative liquid crystal NA-1559 (DIC Corporation) was injected into this empty cell by a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left overnight at 23°C, and then used for evaluation.
[0131] [Evaluation of Liquid Crystal Cell Characteristics] The characteristics of the FFS-driven liquid crystal cell fabricated as described above were evaluated as follows.
[0132] <Measurement of Relaxation Rate of Accumulated Charge> The FFS-driven liquid crystal cell fabricated above was placed between two polarizing plates arranged so that their polarization axes were orthogonal. With the pixel electrode and common electrode short-circuited to the same potential, an LED backlight was shone from below the two polarizing plates, and the angle of the FFS-driven liquid crystal was adjusted so that the brightness of the LED backlight transmitted light measured on the two polarizing plates was minimized. Next, the temperature of the FFS-driven liquid crystal cell was set to 45°C, and the V-T curve (voltage-transmittance curve) was measured while applying an AC voltage of 30 Hz to this liquid crystal cell, and the AC voltage at which the relative transmittance was 23% was calculated as the driving voltage. Furthermore, while driving the FFS-driven liquid crystal cell with an AC voltage of 30 Hz at which the relative transmittance was 23%, a DC voltage of 1 V was simultaneously applied and the cell was driven for 30 minutes. After that, only the application of the DC voltage was stopped, and the cell was driven for another 15 minutes with only the AC voltage. As an evaluation criterion, the decrease in transmittance 15 minutes after the DC voltage application was stopped was expressed as a percentage. A larger decrease in transmittance indicated a greater rate of accumulated charge relaxation, i.e., a better performance.
[0133] Table 3 shows the evaluation results for the reworkability, hygroscopicity, and accumulated charge relaxation rate of each liquid crystal alignment film using the liquid crystal alignment agents described in Examples 1 to 26 and Comparative Examples 1 to 10. In Table 3, the numbers in parentheses for polymers represent the blending ratio (parts by mass) of each polymer (solid content) when the total content of polymers (solid content) contained in the liquid crystal alignment agent is set to 100 parts by mass.
[0134]
[0135] As shown in Table 3, the liquid crystal alignment films obtained from the liquid crystal alignment agent using the specific polymer (B) exhibited better hygroscopicity and reworkability compared to the liquid crystal alignment films obtained from the liquid crystal alignment agent without the specific polymer (B) (comparison between Examples 1-11 and Comparative Examples 1-8, and comparison between Examples 12-26 and Comparative Examples 9-10). Furthermore, the liquid crystal alignment films obtained from the liquid crystal alignment agent of the present invention exhibited a good rate of accumulated charge relaxation. The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2025-011910, filed on January 28, 2025, are incorporated herein by reference as disclosure of the present invention.
Claims
1. A liquid crystal alignment agent comprising the following polymer (A) and polymer (B), wherein at least one of polymer (A) and polymer (B) has a substructure represented by the following formula (DB-1) as a structural unit derived from a diamine. Polymer (A): A polymer selected from the group consisting of a polyimide precursor having a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor has a structural unit (a1) represented by the following formula (A1). Polymer (B): A polymer selected from the group consisting of a polyimide precursor having a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine, and a polyimide which is an imidized product of the polyimide precursor, wherein the polyimide precursor has a structural unit (b1) represented by the following formula (B1) and a structural unit (b2) represented by the following formula (B2). (In formula (A1), X １ This represents a tetravalent organic group represented by the following formula (X-1) or (X-2). Y １ This represents a divalent organic group represented by the following formula (DA-a) and does not have the substructure represented by the above formula (DB-1). R and Z each independently represent a hydrogen atom or a monovalent organic group. Multiple R and Z groups each independently have the above definitions. (In formula (X-1), R １ ~R ４ Each independently represents a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, a C1-C6 alkoxy group, a C2-C6 alkoxyalkyl group, a C2-C6 alkyloxycarbonyl group, or a phenyl group, R １ ~R ４ At least one of the elements represents a group other than a hydrogen atom in the above definition. In formulas (X-1) and (X-2), * represents a bond. ) -Ar-L ０ -Ar'- (DA-a) (In formula (DA-a), Ar and Ar' each independently represent a divalent aromatic ring group. Any hydrogen atom on the rings of Ar and Ar' may be substituted with a monovalent group. L ０ is a single bond, -(CH ２ ), ｎ -(n is an integer from 2 to 18), -COO-, -OCO-, -NR-CO-NR'', -NR-CO-, -NR-CO-, or -(CH ２ ), ｎ in which any -CH ２ - is replaced by a divalent organic group selected from the following group (X), and when L ０ represents a single bond, Ar and Ar' represent aromatic hydrocarbon groups; Group (X): -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-NR'', a divalent cyclic hydrocarbon group, and a divalent heterocyclic group. (R and R'' each independently represent a hydrogen atom or a monovalent organic group. However, -O-, -S-, -COO-, -OCO-, -NR-, -NR-CO-, -CO-NR-, -NR-CO-NR'' are not adjacent to each other. Also, the divalent cyclic hydrocarbon group in group (X) does not directly bond to Ar and Ar').) (In formula (B1), X １’ represents a tetravalent organic group represented by the following formula (X-3). Y １’ represents a divalent organic group. R' and Z' each independently represent a hydrogen atom or a monovalent organic group. A plurality of R' and Z' each independently have the above definitions.) (* represents a bond.) (In formula (B2), X ２’ represents a tetravalent organic group represented by any of the following formulas (X-4) to (X-5). Y ２’ represents the same definition as Y １’ . R' and Z' each independently represent a hydrogen atom or a monovalent organic group. A plurality of R' and Z' each independently have the above definitions.) (* represents a bond.) (In formula (DB-1), A １１ represents a divalent aromatic ring group. B １ is, -NR-A １２ - or -A １３ Represents -. A １２ This represents a divalent aromatic ring group, A １３ A represents a divalent heterocyclic group, and R represents a hydrogen atom or a monovalent organic group. １２ They may also form a ring together. (* represents a bonding hand.) 2. The liquid crystal alignment agent according to claim 1, wherein the content ratio of the polyimide precursor of polymer (B) to the structural unit derived from a tetravalent organic group having a tetravalent organic group represented by formula (X-3) and the structural unit derived from a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic group having a tetravalent organic unit 3. The liquid crystal alignment agent according to claim 1, wherein the total content of structural units derived from a tetracarboxylic acid derivative having a tetravalent organic group represented by formula (X-3) and structural units derived from a tetracarboxylic acid derivative having a tetravalent organic group represented by any of formulas (X-4) to (X-5) in the polyimide precursor of polymer (B) is 40 to 100 mol% with respect to 100 mol% of the total amount of structural units derived from tetracarboxylic acid derivatives in the polyimide precursor of polymer (B).
4. X in the above formula (A1) １ The liquid crystal alignment agent according to claim 1, wherein the tetravalent organic group is selected from the group consisting of the following formulas (x1-1) to (x1-5).
5. A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent according to any one of claims 1 to 4 to a substrate, firing it, and performing an alignment treatment on the resulting film.
6. A liquid crystal alignment film formed from a liquid crystal alignment agent according to any one of claims 1 to 4.
7. A liquid crystal display element comprising the liquid crystal alignment film described in claim 6.
8. The liquid crystal display element according to claim 7, which is driven by an IPS drive system or an FFS drive system.