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

Abstract

To provide a liquid crystal element with good panel transmittance and a liquid crystal alignment agent with excellent coatability. [Solution] A liquid crystal alignment agent containing a polymer [P] which is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and which has at least one specific structure [S] selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure, or a liquid crystal alignment agent containing at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and a compound [A] having the specific structure [S] (excluding polymer [P]), and further containing at least one compound [D1] selected from the group consisting of a compound represented by formula (1), a compound represented by formula (2), a compound represented by formula (3), and a compound represented by formula (4).

Description

[Technical Field]

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. [Background technology]

[0002] In recent years, liquid crystal elements have been used not only in display devices such as personal computers, LCD televisions, car navigation systems, mobile phones, smartphones, and information displays, but also in a wide variety of other applications, such as optical compensation films and dimming films. With this increasing versatility, there is a demand for even higher quality liquid crystal elements, and improvements are being made to the driving method and element structure, as well as to the liquid crystal alignment film, which is one of the components of the liquid crystal element (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses that, in order to further improve the performance of liquid crystal elements, a polymer obtained using a diamine having a structure in which a carbazole structure and a benzene ring are bonded by an amino group is included in the liquid crystal alignment agent.

[0004] Patent Document 2 discloses obtaining a liquid crystal alignment film using a liquid crystal alignment agent containing a compound having a sulfur atom in its molecule and a polymer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2018 / 110354 [Patent Document 2] International Publication No. 2020 / 138112 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] It is conceivable that using a liquid crystal alignment agent containing a polymer having a polycyclic aromatic ring structure, such as the carbazole structure described in Patent Document 1, could increase the refractive index of the liquid crystal alignment film, thereby improving the panel transmittance of the liquid crystal element. However, since the carbazole structure is basic, acid-base interactions can occur between polymers in polymers with acidic groups, which can reduce the solubility of the polymer in the solvent. As a result, in-plane uniformity on the substrate and contact hole coating properties (hereinafter collectively referred to as "coating properties") may be poor.

[0007] Furthermore, compounds and polymers containing sulfur atoms exhibit good solubility in solvents. However, the bonds between sulfur atoms and other atoms can decompose due to heat, and the decomposition products resulting from this thermal decomposition can color the liquid crystal alignment film, raising concerns about a decrease in panel transmittance in liquid crystal elements. To meet the demand for even higher quality liquid crystal elements, it is necessary to satisfy these multiple characteristics simultaneously.

[0008] This invention has been made in view of the above problems, and one of its objectives is to provide a liquid crystal alignment agent that can obtain a liquid crystal element with good panel transmittance and has excellent coatability. [Means for solving the problem]

[0009] According to the present invention, the following liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal elements are provided.

[0010] [1] A polymer [P] having at least one specific structure [S] selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure, or a polymer [A] having the specific structure [S] (excluding polymer [P]), Furthermore, a liquid crystal aligning agent containing at least one compound [D1] selected from the group consisting of a compound represented by the following formula (1), a compound represented by formula (2), a compound represented by formula (3), and a compound represented by formula (4). [Chemical formula] (In formula (1), R , , , ,

[0011] and R 12 are each independently an alkyl group having 1 to 3 carbon atoms. R 13 is an alkyl group having 1 to 6 carbon atoms or a monovalent group in which some hydrogen atoms in an alkyl group having 1 to 6 carbon atoms are replaced by hydroxyl groups.) In formula (2), R 21 is an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 1 to 6 carbon atoms. R 22 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R 23 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 1 to 6 carbon atoms. However, R 22 and R 23 do not simultaneously become hydrogen atoms.) In formula (3), R 31 and R 32 are each independently an alkyl group having 1 to 6 carbon atoms, or R 31 and R 32 are combined with each other to represent a ring structure formed together with -CH2-CO-CH2- to which R 31 and R 32 are bonded.) In formula (4), R 41 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an acetyl group. R 42 is an alkanediyl group having 2 to 4 carbon atoms, and a plurality of R 42 are the same as or different from each other. R 43 is an alkyl group having 1 to 6 carbon atoms or an acetyl group. n is an integer of 2 to 4.)

[0011] [2] A liquid crystal alignment film formed using the liquid crystal aligning agent of [1] above. [3] A liquid crystal element including the liquid crystal alignment film of [2] above. [Effects of the Invention]

[0012] According to the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal element with good panel transmittance and excellent coatability. [Modes for carrying out the invention]

[0013] Liquid crystal alignment agent The liquid crystal alignment agent of this disclosure contains a compound having at least one structure selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure (hereinafter also referred to as "specific structure [S]"), and at least one compound selected from the group consisting of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (3), and the compound represented by formula (4) (hereinafter also referred to as "compound [D1]"). The specific structure [S] is thought to contribute to improving the packing properties of the polymer by engaging in intermolecular interactions (π-π interactions, etc.) with other specific structures [S] or with groups involved in polymer packing, and is considered effective in increasing the refractive index of the liquid crystal alignment film. As a result, it is thought that a liquid crystal element having a liquid crystal alignment film formed with the liquid crystal alignment agent of this disclosure was able to exhibit a high panel transmittance.

[0014] The compound having the specific structure [S] may be a polymer or a nonpolymer. Specific embodiments of the liquid crystal alignment agent of this disclosure include the following embodiments [1] and [2]. [Aspect 1] A liquid crystal alignment agent containing a polymer (hereinafter also referred to as "polymer [P]") having a specific structure [S], which is selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and compound [D1]. [Aspect 2] A liquid crystal alignment agent comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, a compound having a specific structure [S] and different from polymer [P] (hereinafter also referred to as "compound [A]"), and compound [D1].

[0015] In Embodiment 2, the at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide may be polymer [P] or a polymer different from polymer [P]. Furthermore, the liquid crystal alignment agent of each embodiment may further contain components different from the components described above. The components contained in the liquid crystal alignment agent of this disclosure, and other components that may be optionally added as needed, are described below. Unless otherwise specified, each component may be used alone or in combination of two or more.

[0016] Herein, in this specification, "hydrocarbon group" means a group of hydrocarbons that includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Linear hydrocarbon group" means a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure and consists only of a linear structure. However, linear hydrocarbon groups may be saturated or unsaturated. "Alicyclic hydrocarbon group" means a hydrocarbon group that contains only the structure of an alicyclic hydrocarbon as its ring structure and does not contain an aromatic ring structure. However, an alicyclic hydrocarbon group does not have to consist only of the structure of an alicyclic hydrocarbon, and may also include a linear structure as part of it. "Aromatic hydrocarbon group" means a hydrocarbon group that contains an aromatic ring structure as its ring structure. However, an aromatic hydrocarbon group does not have to consist only of an aromatic ring structure, and may also include a linear structure or an alicyclic hydrocarbon structure as part of it. "Aromatic ring" means an aromatic hydrocarbon ring and an aromatic heterocycle. "Organic group" means an atomic group obtained by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0017] The "main chain" of a polymer refers to the "trunk" portion of the polymer, which consists of the longest chain of atoms. This "trunk" portion may contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. "Side chains" refer to the parts of a polymer that branch off from the "trunk." "(meth)acrylic" is a term that encompasses acrylic and methacrylic, and "(meth)acryloyl" is a term that encompasses acryloyl and methacryloyl.

[0018] <Regarding Embodiment 1> [Polymer [P]] The polymer [P] has at least one specific structure [S] selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure. The polymer [P] may have the specific structure [S] in one or both of the main chain and / or side chains, but from the viewpoint of improving panel transmittance in liquid crystal elements, it is preferable that it be present in at least the main chain.

[0019] Specific examples of the specific structure [S] possessed by the polymer [P] include the structures represented by the following formulas (s-1), (s-2), (s-3), and (s-4). [ka] (In equations (s-1), (s-2), (s-3), and (s-4), Y 1 ~Y 6 Each of these is independently a halogen atom, a hydroxyl group, or a monovalent organic group. r1 is an integer from 0 to 6. r2 and r3 are independently integers from 0 to 8. r4 and r5 are independently integers from 0 to 4. r6 is 0 or 1. (* represents a bond.)

[0020] In the above equations (s-1) to (s-4), Y 1 ~Y 6 The monovalent organic group represented by is an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or an alkyl group having 2 to 20 carbon atoms or a halogenated alkyl group having 2 to 20 carbon atoms in which some methylene groups are -O-, -S-, -NR 1 -, -CO-, -COE-, -NR 1 -CO-, -NR 1 -CO-NR 2 - Examples include a monovalent group replaced by a divalent aromatic hydrocarbon ring group, a divalent aliphatic hydrocarbon ring group, or a divalent heterocyclic group.

[0021] R 1 and R 2Each of these is independently a hydrogen atom or a monovalent organic group. R 1 and R 2 Examples of monovalent organic groups represented by include alkyl groups having 1 to 10 carbon atoms or monovalent thermally detachable groups. Examples of monovalent thermally detachable groups include tert-butoxycarbonyl group (Boc group), benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group, 2-(trimethylsilyl)ethoxycarbonyl group, and 9-fluorenylmethyloxycarbonyl group. Of these, the Boc group is particularly preferred because it exhibits excellent thermal detachment properties and can reduce the amount of residual structure in the film after detachment.

[0022] Y 1 ~Y 6 From the viewpoint of improving the panel transmittance of the liquid crystal element, halogen atoms, hydroxyl groups and the above Y 1 ~Y 6 Among the monovalent organic groups represented by , monovalent groups having 1 to 6 carbon atoms are preferred, and halogen atoms, hydroxyl groups and the above Y 1 ~Y 6 Among the monovalent organic groups represented by , monovalent groups having 1 to 4 carbon atoms are more preferred.

[0023] r1 is preferably an integer between 0 and 4, and more preferably an integer between 0 and 2. r2 and r3 are preferably integers between 0 and 6, more preferably integers between 0 and 4, and even more preferably integers between 0 and 2. r4 and r5 are preferably integers between 0 and 2, and more preferably 0 or 1. r6 is preferably 0.

[0024] Here, from the viewpoint of improving the panel transmittance in liquid crystal elements, it is preferable that the specific structure [S] has substituents of a size that does not hinder the improvement of the polymer packing properties due to the specific structure [S], and it is particularly preferable that the specific structure [S] does not have substituents. In other words, Y 1 ~Y 6 It is preferable that the above-mentioned preferred conditions are met, and it is particularly preferable that r1 to r6 are 0.

[0025] From the viewpoint of improving the panel transmittance of the liquid crystal element, it is preferable that the "*" represents a bond with an atom constituting the main chain of the polymer.

[0026] The specific structure [S] of the polymer [P] is preferably at least one selected from the group consisting of naphthalene ring structures and fluorene ring structures, and more preferably at least one selected from the group consisting of structures represented by formulas (s-1), (s-2), and (s-3), respectively, from the viewpoint of obtaining good coating properties.

[0027] Preferred specific examples of the structures represented by equations (s-1) to (s-4) above include the structures represented by equations (g-1) to (g-8) below. [ka] (In equations (g-1) to (g-8), "*" represents a bond.)

[0028] When the specific structure [S] of the polymer [P] is a naphthalene ring structure, it is sufficient that each of the two benzene rings constituting the naphthalene ring is independently bonded to an organic group having a group involved in polymerization, and the bond position is not particularly limited. From the viewpoint of improving the panel transmittance in liquid crystal elements, the naphthalene-diyl group is preferably a naphthalene-2,6-diyl group (structure represented by the above formula (g-1)) or a naphthalene-1,5-diyl group (structure represented by the above formula (g-3)).

[0029] When the specific structure [S] of the polymer [P] is a fluorene ring structure, it is sufficient that each of the two benzene rings constituting the fluorene ring or the two aromatic monocycles included in the substituent of the fluorene ring structure is independently bonded to an organic group having a polymerization-reactive group, and the bond position is not particularly limited. From the viewpoint of improving the panel transmittance in liquid crystal elements, the fluoren-3,6-diyl group (structure represented by formula (g-4) above) and the structure represented by formula (g-6) above are preferred.

[0030] The polymer [P] is preferably a polymer containing structural units derived from monomers having a specific structure [S]. In the polymer [P], the structural units derived from monomers having a specific structure [S] are preferably 2 mol% or more, more preferably 5 mol% or more, and particularly preferably 10 mol% or more, relative to the total amount of structural units derived from monomers constituting the polymer [P], from the viewpoint of improving the panel transmittance of the liquid crystal element. Furthermore, from the viewpoint of obtaining good coatability, the structural units derived from monomers having a specific structure [S] are preferably 45 mol% or less, more preferably 40 mol% or less, and particularly preferably 35 mol% or less, relative to the total amount of structural units derived from monomers constituting the polymer [P].

[0031] The main skeleton of polymer [P] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The method for producing polyamic acid, polyamic acid ester, and polyimide as polymer [P] is not particularly limited and can be produced by appropriately combining standard organic chemistry methods. The details of polyamic acid, polyamic acid ester, and polyimide as polymer [P] will be described below.

[0032] [Polyamic acid] Methods for obtaining polyamic acid as polymer [P] (hereinafter also referred to as "polyamic acid (P)") include, for example, (1) a polymerization method using a tetracarboxylic dianhydride containing a tetracarboxylic dianhydride having a specific structure [S] (hereinafter also referred to as "specific acid dianhydride") and a diamine, (2) a polymerization method using a tetracarboxylic dianhydride and a diamine containing a diamine having a specific structure [S] (hereinafter also referred to as "specific diamine"), or a method combining method (1) and method (2).

[0033] (Tetracarboxylic acid dianhydride) The specific acid dianhydride only needs to have a specific structure [S], and other structures are not particularly limited. Preferred specific examples of the specific acid dianhydride include the compounds represented by the following formulas (st-1) and (st-2). [ka] (In equations (st-1) and (st-2), A 1 This is the structure represented by formula (s-1), the structure represented by formula (s-2), or the structure represented by formula (s-4). 1 and X 2 Each of these is independently a single bond or a divalent linking group. 1 and Ar 2 Each of these is independently a trivalent aromatic hydrocarbon ring group, a trivalent aliphatic hydrocarbon ring group, or a trivalent heterocyclic group. p1 and p2 are independently 0 or 1. 3 ~Y 5 And r3 to r5 are equivalent to the above equation (s-3).

[0034] In the above equations (st-1) and (st-2), X 1 and X 2 Examples of divalent linking groups represented by -O-, -S-, and -NR 3 -, -CO-, -COE-, -NR 3 -CO-, -NR 3 -CO-NR 4 - A part of the methylene group in an alkanediyl group having 1 to 20 carbon atoms, or an alkanediyl group having 2 to 20 carbon atoms, is -O-, -S-, -NR 3 -, -CO-, -COE-, -NR 3 -CO- or -NR 3 -CO-NR 4 Examples include divalent groups that have been replaced with -, such as -O-, -S-, and -NR. 3 -, -CO-, -COE-, -NR 3 -CO-, -NR 3 -CO-NR 4 - Alkanediyl groups with 1 to 5 carbon atoms, or some methylene groups in alkanediyl groups with 2 to 5 carbon atoms, are -O-, -S-, -NR 3-, -CO-, -COE-, -NR 3 -CO- or -NR 3 -CO-NR 4 A divalent group replaced with - is preferred. 3 and R 4 Regarding the above R 1 and R 2 The explanation applies.

[0035] Ar 1 and Ar 2 The trivalent aromatic hydrocarbon ring group, trivalent aliphatic hydrocarbon ring group, and trivalent heterocyclic group represented by are trivalent groups obtained by removing three hydrogen atoms from the ring portion of an aromatic hydrocarbon ring, aliphatic hydrocarbon ring, or heterocyclic ring. 1 and Ar 2 Preferably, the group is a trivalent aromatic hydrocarbon ring group or a trivalent aliphatic hydrocarbon ring group, more preferably a trivalent group obtained by removing three hydrogen atoms from the ring portion of a benzene ring, naphthalene ring, cyclopentane ring, or cyclohexane ring, and even more preferably a trivalent group obtained by removing three hydrogen atoms from the ring portion of a benzene ring or cyclohexane ring.

[0036] Specific examples of specific acid dianhydrides include the compounds represented by formulas (ta-1) to (ta-5), (tb-1) to (tb-4), (tc-1), and (tc-2), respectively. In the structural formulas, "Boc" represents a tert-butoxycarbonyl group (the same applies below). [ka] [ka] [ka]

[0037] Of these specific acidic dianhydrides, compounds having a fluorene ring structure are preferred in terms of ease of synthesis, and the compound represented by the above formula (st-2) is more preferred.

[0038] The tetracarboxylic dianhydride used in the synthesis of polyamic acid (P) may be a specific acid dianhydride only. Alternatively, the tetracarboxylic dianhydride used in the synthesis of polyamic acid (P) may be a specific acid dianhydride and a tetracarboxylic dianhydride that does not have the specific structure [S] (hereinafter also referred to as "other acid dianhydrides").

[0039] Other examples of acidic dianhydrides include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. Aliphatic tetracarboxylic dianhydrides include linear tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0040] Specific examples of linear tetracarboxylic dianhydrides include, for example, butanetetracarboxylic dianhydride. Specific examples of alicyclic tetracarboxylic dianhydrides include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, and 3-oxabicyclo[3.2.1]octane-2,4-dione. n-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid 2:3,5:6-dianhydride, 4,9-dioxatricyclo[5.3.1.0 2,6Examples include undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylenediaminetetraacetic acid dianhydride, and cyclopentanetetracarboxylic dianhydride.

[0041] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylenebis(trimellitic monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4'-biphthalic dianhydride. In addition to the above, tetracarboxylic dianhydrides described in Japanese Patent Publication No. 2010-97188 can be used as tetracarboxylic dianhydrides for the synthesis of polyamic acid (P).

[0042] The tetracarboxylic dianhydride used in the synthesis of polyamic acid (P) preferably contains at least one selected from the group consisting of linear tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and more preferably contains alicyclic tetracarboxylic dianhydride, in order to increase the solubility of the polymer and to obtain a liquid crystal alignment film exhibiting good electrical properties. The amount of alicyclic tetracarboxylic dianhydride used is preferably 20 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more, relative to the total amount of tetracarboxylic dianhydride used in the synthesis of polyamic acid (P).

[0043] In the synthesis of polyamic acid (P), the proportion of specific acid dianhydrides used is preferably 2 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to the total amount of tetracarboxylic dianhydrides used in the synthesis of polyamic acid (P). A proportion of specific acid dianhydrides within the above range is advantageous in terms of improving the panel transmittance in liquid crystal elements. Furthermore, all of the tetracarboxylic dianhydrides used in the synthesis of polyamic acid (P) may be specific acid dianhydrides. Also, when other acid dianhydrides are used to impart desired properties, the proportion of specific acid dianhydrides used is preferably 90 mol% or less, and more preferably 80 mol% or less, relative to the total amount of tetracarboxylic dianhydrides used in the synthesis of polyamic acid (P).

[0044] (Diamine) In the synthesis of polyamic acids (P), specific diamines can be preferably used. The specific diamine only needs to have a specific structure [S], and other structures are not particularly limited. Examples of specific diamines include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes. A preferred specific example of a specific diamine is a compound represented by the following formula (sa). [ka] (In formula (sa), A 2 This is the structure represented by formula (s-1), the structure represented by formula (s-2), the structure represented by formula (s-3), or the structure represented by formula (s-4). 3 and X 4 Each of these is independently a single bond or a divalent linking group. 3 and Ar 4 These are, independently, a single bond, a divalent aromatic hydrocarbon ring group, a divalent aliphatic hydrocarbon ring group, or a divalent heterocyclic group.

[0045] In the above formula (sa), X 3 and X 4 Examples of divalent linking groups represented by -O-, -S-, and -NR 5-, -CO-, -COO-, -NR 5 -CO-, -NR 5 -CO-NR 6 -, -SO2-, -O-SO2-, an alkane diyl group having 1 to 20 carbon atoms, or some methylene groups in an alkane diyl group having 2 to 20 carbon atoms are -O-, -S-, -NR 5 -, -CO-, -COO-, -NR 5 -CO-, -NR 5 -CO-NR 6 - or a divalent group such as -SO2- that has been replaced. X 3 and X 4 As, a single bond, -O-, -S-, -NR 5 -, -CO-, -COO-, -NR 5 -CO-, -NR 5 -CO-NR 6 -, -SO2-, -O-SO2-, an alkane diyl group having 1 to 5 carbon atoms, or some methylene groups in an alkane diyl group having 2 to 5 carbon atoms are -O-, -S-, -NR 5 -, -CO-, -COO-, -NR 5 -CO-, -NR 5 -CO-NR 6 - or a divalent group replaced by -SO2- is preferred. R 5 and R 6 Regarding, the above R 1 and R 2 The description applies.

[0046] Ar 3 and Ar 4 For the divalent aromatic hydrocarbon ring group, divalent aliphatic hydrocarbon ring group, and divalent heterocyclic group represented by, except for the difference in valence, the description of the trivalent aromatic hydrocarbon ring group, trivalent aliphatic hydrocarbon ring group, and trivalent heterocyclic group represented by the above Ar 1 and Ar 2 applies. A 2 From the viewpoint of obtaining good coating properties, the structure represented by the above formula (s-1), the structure represented by the formula (s-2), or the structure represented by the formula (s-3) is preferred, and the structure represented by the formula (s-2) or the structure represented by the formula (s-3) is more preferred.

[0047] Specific examples of specific diamines include, for example, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3,5-dimethylphenyl)fluorene, 1,5-diaminonaphthalene, and compounds represented by the following formulas (da-1) to (da-10), (db-1) to (db-13), and (dc-1). [ka] [ka] [ka]

[0048] Of the specific diamines, those represented by formulas (da-1) to (da-8), (db-1) to (db-12), and (dc-1) are preferred in that they can improve the panel transmittance in liquid crystal elements. In particular, those represented by formulas (da-1) to (da-8) and (db-1) to (db-12) are preferred in that they can provide excellent coating properties for liquid crystal alignment agents, and those represented by formulas (da-1), (da-5), (da-8), and (db-5) are more preferred.

[0049] The diamine compound used in the synthesis of polyamic acid (P) may consist solely of a specific diamine. Alternatively, the diamine compound used in the synthesis of polyamic acid (P) may be a combination of a specific diamine and a diamine that does not have a specific structure [S] (hereinafter also referred to as "other diamines").

[0050] Other diamines include, for example, aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include linear diamines and alicyclic diamines.

[0051] Other specific examples of diamines include, as chain-like diamines, m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, etc. Examples of alicyclic diamines include 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); Aromatic diamines include, for example, dodecanoxydiaminobenzene, tetradecanoxydiaminobenzene, pentadecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostanyl diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1 ,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, N-(2,4-diaminophenyl)-4-(4-heptylcyclohexyl)benzamide, formula (E-1) [ka] (In formula (E-1), X I and X II These are, independently, a single bond, -O-, *-COO-, or *-OCO- (where "*" represents a bond with the diaminophenyl group). I This is an alkanediyl group with 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III(where a is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer between 0 and 3. c is an integer between 0 and 2. d is 0 or 1. However, 1 ≤ a + b + c ≤ 3.) Diamines containing directing groups, such as compounds represented by: Paraphenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis(4-aminophenoxy)heptane, bis(4-aminophenoxy) Su[2-(4-aminophenyl)ethyl]hexanediic acid, N,N-bis(4-aminophenyl)methylamine, N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, 4,4'-(2,2'-oxybis(ethane-1,2-diyl)bis(oxy))dianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-Bis[4-(4-aminophenoxy)phenyl]propane, 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-Bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)bisaniline, 1,4-Bis(4-aminophenoxy)benzene, 4,4'-Bis(4-aminophenoxy)biphenyl, 2,6-Diaminopyridine, 2,4-Diaminopyrimidine, 3,6-Diaminoacridin, 3,6-Diamino Minocarbazole, N-methyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-piperazine, 3,5-diaminobenzoic acid, 1-(4-aminophenoxy)-2-(4-(4'-aminophenyl)phenoxy)ethane, 3,5-diamino-N,N-bis(pyridine-3-ylmethyl)benzamide, formulas (de-1) to (de-19) below [ka] [ka] Diamines, etc., represented by each of the following; Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and diamines described in Japanese Patent Publication No. 2010-97188 can also be used.

[0052] In the above equation (E-1), "-X I -(R I -X II The divalent group represented by ")d-" is preferably an alkanediyl group having 1 to 3 carbon atoms, *-O-, *-COO-, or *-O-C2H4-O- (where the bond marked with "*" is bonded to a diaminophenyl group). III The group represented by is preferably linear. The two amino groups in the diaminophenyl group are preferably located at the 2,4- or 3,5-positions relative to the other group.

[0053] Specific examples of compounds represented by the above formula (E-1) include, for example, the compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0054] In the synthesis of polyamic acid (P), the proportion of specific diamine used is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P). A specific diamine usage within the above range is advantageous in that it can improve the panel transmittance in liquid crystal elements. Furthermore, all of the diamines used in the synthesis of polyamic acid (P) may be specific diamines. Also, when other diamines are used to impart desired properties, the proportion of specific diamine used is preferably 80 mol% or less, and more preferably 70 mol% or less, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P).

[0055] (Synthesis of polyamic acids) Polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound as described above, along with a molecular weight adjusting agent as needed. The ratio of tetracarboxylic dianhydride and diamine compound used in the synthesis reaction of polyamic acid (P) is preferably such that the acid anhydride groups of the tetracarboxylic dianhydride are in the proportion of 0.2 to 2 equivalents, and more preferably 0.3 to 1.2 equivalents, per 1 equivalent of amino groups of the diamine compound.

[0056] Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The proportion of molecular weight modifier used is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the total amount of tetracarboxylic dianhydride and diamine compound used.

[0057] The synthesis reaction of polyamic acid (P) is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0058] Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Of these organic solvents, it is preferable to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (organic solvents of group 1), or a mixture of one or more selected from the organic solvents of group 1 and one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (organic solvents of group 2). In the latter case, the proportion of organic solvents of group 2 used is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to the total amount of organic solvents of group 1 and group 2.

[0059] Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenol, or a mixture of one or more of these and other organic solvents within the above proportion range. The amount of organic solvent used (x) is preferably such that the total amount of tetracarboxylic dianhydride and diamine compound (y) is 0.1 to 50% by mass of the total amount of the reaction solution (x+y).

[0060] As described above, a reaction solution is obtained by dissolving polyamic acid (P). This reaction solution may be used as is for the preparation of the liquid crystal alignment agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamic acid (P) may be purified and then used for the preparation of the liquid crystal alignment agent. When dehydrating and cyclizing the polyamic acid (P) to obtain polyimide, the above reaction solution may be used as is for the dehydration and cyclization reaction, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the dehydration and cyclization reaction, or the isolated polyamic acid (P) may be purified and then used for the dehydration and cyclization reaction. The isolation and purification of polyamic acid (P) can be carried out according to known methods.

[0061] [Polyamic acid ester] Polyamic acid esters as polymers [P] can be obtained, for example, by [I] reacting the polyamic acid (P) obtained by the above synthesis reaction with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine compound, [III] reacting a tetracarboxylic acid dihalide with a diamine compound, etc.

[0062] In this specification, "tetracarboxylic acid diester" means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are carboxyl groups. "Tetracarboxylic acid diester dihalide" means a compound in which two of the four carboxyl groups of tetracarboxylic acid are esterified and the remaining two are halogenated.

[0063] Examples of esterifying agents used in Method [I] include hydroxyl group-containing compounds, acetal compounds, halides, and epoxy group-containing compounds. Specific examples include, as hydroxyl group-containing compounds, alcohols such as methanol, ethanol, and propanol, and phenols such as phenol and cresol; as acetal compounds, N,N-dimethylformamide diethyl acetal and N,N-diethylformamide diethyl acetal; as halides, methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, and 1,1,1-trifluoro-2-iodoethane; and as epoxy group-containing compounds, propylene oxide.

[0064] The tetracarboxylic acid diester used in Method [II] can be obtained, for example, by opening the ring of a tetracarboxylic acid dianhydride, as exemplified in the description of the synthesis of polyamic acid (P), using an alcohol such as methanol or ethanol. Furthermore, the specific acid dianhydride exemplified in the description of polyamic acid (P) may be used alone, or other acid dianhydrides may be used in combination. The tetracarboxylic acid derivative used in Method [II] may be a tetracarboxylic acid diester only, or tetracarboxylic acid dianhydrides may be used in combination. For the diamine compound, the specific diamine exemplified in the synthesis of polyamic acid may be used alone, or other diamines may be used in combination.

[0065] The reaction of method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. Examples of organic solvents include those used in the synthesis of polyamic acid (P). Examples of dehydration catalysts include 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium halide, carbonylimidazole, and phosphorus-based condensing agents. The reaction temperature is preferably -20 to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0066] The tetracarboxylic acid diester dihalides used in Method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride. The tetracarboxylic acid derivative used in Method [III] may be a tetracarboxylic acid diester dihalide alone, or a tetracarboxylic acid dianhydride may be used in combination. Furthermore, for the diamine compound, the specific diamine exemplified in the description of the synthesis of polyamic acid (P) may be used alone, or other diamines may be used in combination.

[0067] The reaction of method [III] is preferably carried out in an organic solvent in the presence of a suitable base. Examples of organic solvents include those exemplified for use in the synthesis of polyamic acid (P). Suitable bases include tertiary amines such as pyridine and triethylamine; and alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, and potassium. The reaction temperature is preferably -20 to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0068] The polyamic acid ester contained in the liquid crystal alignment agent may have only an amic acid ester structure, or it may be a partially esterified product in which both an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used directly in the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used in the preparation of the liquid crystal alignment agent, or the isolated polyamic acid ester may be purified and then used in the preparation of the liquid crystal alignment agent. The isolation and purification of the polyamic acid ester can be carried out according to known methods.

[0069] [Polyimide] Polyimides as polymers [P] can be obtained, for example, by dehydrating and cyclizing polyamic acid (P) synthesized as described above to form imidates.

[0070] Polyimide may be a fully imidized product obtained by dehydrating and cyclizing all of the amic acid structure present in its precursor, polyamic acid, or it may be a partially imidized product in which only a portion of the amic acid structure is dehydrated and cyclized, resulting in the coexistence of amic acid and imide ring structures. The polyimide used in the reaction preferably has an imidation rate of 20% or more, more preferably 30-99%, and even more preferably 40-99%. This imidation rate is expressed as a percentage of the ratio of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, a portion of the imide ring may be an isoimide ring.

[0071] Dehydration and ring closure of polyamic acid is preferably carried out by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration and ring closure catalyst to the solution, and heating as necessary.

[0072] In a method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid, the dehydrating agent can be an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid. As the dehydration ring-closing catalyst, a tertiary amine such as pyridine, colidine, lutidine, triethylamine, or 1-methylpiperidine can be used. The amount of dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include those exemplified as those used in the synthesis of polyamic acid. The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, more preferably 10 to 150°C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

[0073] In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as is for the preparation of the liquid crystal alignment agent, or the dehydrating agent and dehydration ring-closing catalyst may be removed from the reaction solution before preparing the liquid crystal alignment agent, or the polyimide may be isolated before preparing the liquid crystal alignment agent, or the isolated polyimide may be purified before preparing the liquid crystal alignment agent. These purification operations can be carried out according to known methods. In addition, polyimide can also be obtained by imidization of polyamic acid esters.

[0074] The polymer [P] obtained as described above preferably has a solution viscosity of 20 to 1,800 mPa·s when it is prepared as a 15% by mass solution, and more preferably has a solution viscosity of 50 to 1,500 mPa·s. The solution viscosity (mPa·s) of the polymer is the value measured at 25°C using an E-type rotational viscometer for a 15% by mass polymer solution prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0075] The weight-average molecular weight (Mw) of polymer [P] measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. Furthermore, for polymer [P], the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC, is preferably 8 or less, and more preferably 6 or less. By having Mw and Mw / Mn of polymer [P] within the above ranges, good liquid crystal alignment of the liquid crystal element can be ensured.

[0076] The content of polymer [P] in the liquid crystal alignment agent of Embodiment 1 is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total amount of solids contained in the liquid crystal alignment agent (components other than the solvent component of the liquid crystal alignment agent).

[0077] [Compound D1] The liquid crystal alignment agent of this disclosure contains compound [D1]. By using compound [D1] in combination with a liquid crystal alignment agent containing a compound having a specific structure [S] as a solvent component, a liquid crystal alignment agent exhibiting good coatability can be obtained, and a liquid crystal element with excellent panel transmittance can be obtained.

[0078] Compound [D1] is at least one selected from the group consisting of the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (3), and the compound represented by formula (4). [ka] (In formula (1), R 11 and R 12 Each of these is an alkyl group having 1 to 3 carbon atoms. 13 This refers to a monovalent group in which an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, has some of its hydrogen atoms replaced by hydroxyl groups. In formula (2), R 21 R is an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 1 to 6 carbon atoms. 22 R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 23 R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxyalkyl group having 1 to 6 carbon atoms. However, R 22 and R 23 They do not simultaneously become hydrogen atoms. In formula (3), R 31 and R 32 Each of these is independently either an alkyl group having 1 to 6 carbon atoms, or R 31 and R 32 When combined, R 31 and R 32 This represents a ring structure formed together with the -CH2-CO-CH2- bonded to it. In formula (4), R 41 R is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an acetyl group. 42 This is an alkanediyl group having 2 to 4 carbon atoms, and multiple R 42 They are either identical or different from each other. 43(where n is an alkyl group or acetyl group having 1 to 6 carbon atoms; n is an integer between 2 and 4.)

[0079] In the above equation (1), R 11 and R 12 The group is preferably a methyl group or an ethyl group, with a methyl group being more preferred. R 13 If it does not have a hydroxyl group, a methyl group or an ethyl group is preferred, and a methyl group is more preferred. 13 If the group has a hydroxyl group, a monovalent group in which some of the hydrogen atoms in the C4-C6 alkyl group are replaced by a hydroxyl group is preferred, and a monovalent group in which some of the hydrogen atoms in the isobutyl group are replaced by a hydroxyl group is more preferred.

[0080] In equation (2) above, R 21 The alkyl group is preferably a C1-C6 alkyl group, and more preferably a C1-C4 alkyl group. R 22 The component is preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group. R 23 The alkyl group is preferably a C1-C3 alkyl group, and more preferably a methyl group or an ethyl group.

[0081] In the above equation (3), R 31 and R 32 The alkyl group is preferably a C1-C6 alkyl group, and more preferably a C1-C3 alkyl group.

[0082] R 31 and R 32 When combined, R 31 and R 32 When referring to a ring structure formed together with the -CH2-CO-CH2- to which it is bonded, examples of such ring structures include cyclohexanone structures, 3-methylcyclohexanone structures, and 4-methylcyclohexanone structures.

[0083] In the above equation (4), R 41 The alkyl group is preferably a C1-C6 alkyl group, and more preferably a C1-C3 alkyl group. R42 The group is preferably an alkanediyl group having 2 or 3 carbon atoms, and more preferably an ethylene group or an isopropylene group. R 43 The alkyl group is preferably a C1-C6 alkyl group, and more preferably a C1-C3 alkyl group. n is preferably 2 or 3.

[0084] Specific examples of compound [D1] include the compounds represented by the following formulas: (D1-1-1), (D1-1-2), (D1-2-1) to (D1-2-14), (D1-3-1) to (D1-3-21), and (D1-4-1) to (D1-4-23). [ka] [ka] [ka] [ka]

[0085] As compound [D1], it is preferable to use the compounds represented by (D1-1-1), (D1-1-2), (D1-2-1), (D1-2-2), (D1-2-6), (D1-3-1), (D1-4-1), and (D1-4-7), respectively, and it is more preferable to use the compounds represented by (D1-1-1), (D1-2-1), (D1-3-1), and (D1-4-1), respectively.

[0086] In the liquid crystal alignment agent, the content of compound [D1] is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more, relative to the total amount of solvent components contained in the liquid crystal alignment agent, from the viewpoint of improving the coatability of the liquid crystal alignment agent. Furthermore, from the above viewpoint, the content of compound [D1] is preferably 80% by mass or less, even more preferably 75% by mass or less, and particularly preferably 70% by mass or less.

[0087] [Other ingredients] The liquid crystal alignment agent of Embodiment 1 may contain, in addition to the polymer [P] and compound [D1], other components as needed. Examples of other components include polymers that do not have a specific structure [S] (hereinafter also referred to as "polymer [Q]"), solvent components different from compound [D1] (hereinafter also referred to as "other solvents"), crosslinking agents, antioxidants, metal chelating compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, and the like. The content ratio of the other components can be appropriately selected according to each compound, within a range that does not impair the effects of the present invention.

[0088] [Polymer[Q]] Polymer [Q] is used, for example, to suppress a decrease in voltage retention or to improve liquid crystal alignment. The main skeleton of polymer [Q] is not particularly limited, but examples include polymers with polyamic acid, polyamic acid esters, polyimides, polyorganosiloxanes, polyesters, cellulose derivatives, polyacetals, and addition polymers as the main skeleton. Addition polymers are polymers that contain structural units derived from monomers having polymerizable unsaturated carbon-carbon bonds, and examples include styrene polymers, (meth)acrylic polymers, maleimide polymers, (meth)acrylic-styrene copolymers, (meth)acrylic-maleimide copolymers, (meth)acrylic-styrene-maleimide copolymers, and styrene-maleimide copolymers. Polymer [Q] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid esters, polyimides, polyorganosiloxanes, and addition polymers.

[0089] Furthermore, when used as a liquid crystal alignment agent for photo-alignment processing, polymer [P] may contain a photosensitive polymer, and polymer [Q] may contain a non-photosensitive polymer. Alternatively, polymer [P] may contain a non-photosensitive polymer, and polymer [Q] may contain a photosensitive polymer. In addition, both polymer [P] and polymer [Q] may contain photosensitive polymers.

[0090] When the liquid crystal alignment agent of embodiment 1 contains polymer [Q], the content ratio of polymer [Q] is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of polymer components contained in the liquid crystal alignment agent (i.e., the total amount of polymer [P] and polymer [Q]).

[0091] [Other solvents] In the liquid crystal alignment agent of Embodiment 1, compound [D1] alone may be used as the solvent component, but other solvents may be used to improve the solubility of the polymer component.

[0092] Other solvents that can be used include at least one solvent selected from the group consisting of aprotic polar solvents and phenolic solvents (hereinafter also referred to as "compound [D2]"). Specific examples of these include, as aprotic polar solvents, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, tetramethylurea, hexamethylphosphotriamide, propylene carbonate, 3-butoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-hexyloxy-N,N-dimethylpropanamide, isopropyloxy-N-isopropyl-propionamide, n-butoxy-N-isopropyl-propionamide, etc. Examples of phenolic solvents include m-cresol, xylenol, phenol, and halogenated phenols.

[0093] As compound [D2], it is preferable to use an aprotic polar solvent, and more preferably to use at least one selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and γ-butyrolactone.

[0094] In the liquid crystal alignment agent of Embodiment 1, when compound [D2] is included, the content of compound [D2] is preferably 15% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more, based on the total amount of solvent components contained in the liquid crystal alignment agent, from the viewpoint of improving the solubility of the polymer components. Furthermore, from the viewpoint of not inhibiting the action of compound [D1], the content of compound [D2] is preferably 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 40% by mass or less, based on the total amount of solvent components contained in the liquid crystal alignment agent.

[0095] [Crosslinking agent] The liquid crystal alignment agent of embodiment 1 may contain a crosslinking agent. Examples of crosslinking agents include oxyranyl groups, oxetanyl groups, cyclic thioether groups, cyclic carbonate groups, hydroxyl groups, protected hydroxyl groups, methylol groups, protected methylol groups, mercapto groups, protected mercapto groups, amino groups, protected amino groups, isocyanate groups, protected isocyanate groups, alkoxysilyl groups, polymerizable carbon-carbon unsaturated bond groups (alkenyl groups, vinyl ether groups, vinylphenyl groups, maleimide groups, (meth)acryloyl groups, etc.), β-hydroxyalkylamide groups, β-alkoxyalkylamide groups, oxazoline groups, aldehyde groups, carbodiimide groups, protected carboxyl groups, and the group "-CR". 60 =CR 61 -R 62 -" However, R 60 R is a monovalent organic group that is eliminated by reaction with an amino group. 61 R is a hydrogen atom or an alkyl group.62 Compounds having two or more groups selected from the group consisting of electron-withdrawing groups, silanol groups, and alkoxysilyl groups are preferably used.

[0096] Specific examples of crosslinking agents include compounds represented by formulas (c-1) to (c-19) below. [ka] [ka] (In formula (c-8), Ac represents an acetyl group.) [ka] (In equations (c-10) and (c-11), R 93 (This is a tert-butoxy group.) [ka]

[0097] When a crosslinking agent is added to the liquid crystal alignment agent of Embodiment 1, the crosslinking agent content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent of Embodiment 1 (i.e., the total amount of polymer [P] and polymer [Q]). Furthermore, the crosslinking agent content is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, based on 100 parts by mass of the total amount of polymer components.

[0098] <Regarding the second aspect> The liquid crystal alignment agent of Embodiment 2 contains at least one polymer (hereinafter also referred to as "polymer [R]") selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, compound [A], and compound [D1]. The polymer [R] contained in the liquid crystal alignment agent of Embodiment 2 may be polymer [P], or at least one polymer [Q] selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The description in Embodiment 1 applies to the polymer [R], compound [D1], and other components contained in the liquid crystal alignment agent of Embodiment 2.

[0099] [Compound [A]] The liquid crystal alignment agent of embodiment 2 contains a compound [A] having a specific structure [S] (excluding polymer [P]). Compound [A] may be a nonpolymer or a polymer. This polymer is a polymer different from polymer [P] and polymer [Q] (hereinafter also referred to as "polymer [T]"), differing from polymer [P] in that its main skeleton is not polyamic acid, polyamic acid ester, and polyimide, and differing from polymer [Q] in that it has a specific structure [S].

[0100] If compound [A] is a nonpolymer, specific examples of the particular structure [S] that compound [A] possesses include the structures represented by formulas (s-5), (s-6), (s-7), and (s-8) below. [ka] (In equations (s-5), (s-6), (s-7), and (s-8), Y 7 ~Y 12 Each of these is independently a halogen atom or a monovalent organic group. r7 is an integer between 0 and 6. r8 is an integer between 0 and 8. r9 is an integer between 0 and 8. r10 and r11 are independently integers between 0 and 5. r12 is an integer between 0 and 3.

[0101] In equations (s-5) to (s-8) above, Y 7 ~Y 12The monovalent organic group represented by the above Y 1 ~Y 6 The explanation of a monovalent organic group represented by applies.

[0102] For r7, the explanation for r1 above applies. For r8 and r9, the explanations for r2 and r3 above apply. For r10 and r11, the explanations for r4 and r5 above apply. For r12, the explanation for r6 above applies.

[0103] If compound [A] is a nonpolymer, it is preferable that compound [A] further has crosslinkable groups within the molecule. When compound [A] has crosslinkable groups, it is effective in further increasing the refractive index of the liquid crystal alignment film by reacting with the functional groups of the polymer or by the crosslinkable groups of compound [A] reacting with each other, thereby further increasing the panel transmittance in the liquid crystal element. The number of crosslinkable groups that compound [A] has is preferably one or more, more preferably two or more in total, even more preferably 2 to 12 in total, and particularly preferably 2 to 10 in total.

[0104] The crosslinkable groups of compound [A] include the crosslinkable groups that the crosslinking agents of the other components mentioned above may have. Among these, from the viewpoint of improving the panel transmittance in liquid crystal elements, it is preferable that the crosslinkable group is at least one selected from the group consisting of oxyranyl group, oxetanyl group, hydroxyl group, protected hydroxyl group, methylol group, protected methylol group, alkoxysilyl group, polymerizable carbon-carbon unsaturated bond group, β-hydroxyalkylamide group, and alkoxysilyl group. Furthermore, from the viewpoint of achieving both panel transmittance and coatability in liquid crystal elements, it is even more preferable that the crosslinkable group is at least one selected from the group consisting of hydroxyl group, protected hydroxyl group, methylol group, protected methylol group, alkoxysilyl group, polymerizable carbon-carbon unsaturated bond group, β-hydroxyalkylamide group, and alkoxysilyl group.

[0105] As compound [A], it is preferable that the structure represented by each of the above formulas (s-5) to (s-8) has multiple crosslinking groups attached via single bonds or divalent organic groups. A specific example of such compound [A] is the compound represented by the following formula (sd). [ka] (In formula (sd), A 3 This is a group obtained by removing p3 hydrogen atoms from the structure represented by formula (s-5), formula (s-6), formula (s-7), or formula (s-8) above. 5 R is a single bond or a divalent organic group. 5 This is a crosslinking group. p3 is an integer between 2 and 12. Multiple X 5 and R 5 (These are either identical or different from each other.)

[0106] In the above formula (sd), X 5 Divalent organic groups represented by include substituted or unsubstituted divalent hydrocarbon groups having 1 to 20 carbon atoms, or substituted or unsubstituted hydrocarbon groups having 2 to 20 carbon atoms in which some methylene groups are -O-, -S-, -NR 8 -, -CO-, -COE-, -NR 8 -CO- or -NR 8 -CO-NR 9 Examples include divalent groups that have been replaced with -. Examples of divalent hydrocarbon groups having 1 to 20 carbon atoms include divalent linear hydrocarbon groups having 1 to 20 carbon atoms, divalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms. Examples of substituents introduced to hydrocarbon groups include alkoxy groups having 1 to 6 carbon atoms, halogen atoms, and crosslinking groups. The description of the crosslinking group possessed by compound [A] above applies to the crosslinking group. R 8 and R 9 Regarding the above R 1 and R 2 The explanation applies.

[0107] R 5The description of the crosslinking group possessed by compound [A] above applies to the crosslinking group represented by . p3 is preferably an integer between 2 and 10, more preferably an integer between 2 and 8, and particularly preferably an integer between 2 and 6. The compound represented by formula (sd) preferably has a total of 2 to 12 crosslinkable groups, and more preferably a total of 2 to 10.

[0108] Specific examples of compound [A] include, for example, the compounds of formulas (ad-1) to (ad-4), (bd-1) to (bd-4), and (cd-1) to (cd-5) shown below. [ka] [ka] [ka]

[0109] When compound [A] is a polymer [T], its main skeleton can be a polyorganosiloxane, polyester, cellulose derivative, polyacetal, or addition polymer. Among these, polyorganosiloxane and addition polymer are preferred. Specific examples of the specific structure [S] possessed by polymer [T] include the structures represented by formulas (s-1), (s-2), (s-3), and (s-4), which are specific examples of the specific structure [S] possessed by polymer [P], and the descriptions thereof apply. In polymer [T], the structures represented by formulas (s-1), (s-2), (s-3), and (s-4) are preferably included in the side chains of the polymer from the viewpoint of ease of introducing the specific structure [S] into the polymer.

[0110] In the liquid crystal alignment agent of embodiment 2, the content of compound [A] is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent (i.e., the total amount of polymer [P], polymer [Q], and polymer [T]). Setting the content of compound [A] within the above range is preferable from the viewpoint of improving the panel transmittance in the liquid crystal element. Furthermore, from the viewpoint of suppressing a decrease in the coatability of the liquid crystal alignment agent due to the addition of an excessive amount, the content of compound [A] is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent.

[0111] In particular, when compound [A] is a nonpolymer, the content of compound [A] is preferably 0.1 parts by mass or more, and more preferably 0.3 parts by mass or more, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent. Furthermore, the content of compound [A] is preferably 40 parts by mass or less, and more preferably 35 parts by mass or less, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent.

[0112] In particular, when compound [A] is a polymer [T], the content of compound [A] is preferably 1 part by mass or more, and more preferably 3 parts by mass or more, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent. Furthermore, the content of compound [A] is preferably 50 parts by mass or less, and more preferably 40 parts by mass or less, based on 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent.

[0113] The solid content concentration (the ratio of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) in the liquid crystal alignment agent of Embodiment 1 and Embodiment 2 is appropriately selected considering viscosity, volatility, etc., but is preferably in the range of 1 to 10% by mass. When the solid content concentration is 1% by mass or more, a sufficient film thickness of the coating can be secured, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties is easily obtained. On the other hand, when the solid content concentration is 10% by mass or less, the coating can be made of an appropriate thickness, a liquid crystal alignment film exhibiting good liquid crystal alignment properties is easily obtained, and the viscosity of the liquid crystal alignment agent tends to be appropriate, resulting in good coatability.

[0114] <Liquid crystal alignment films and liquid crystal elements> The liquid crystal alignment film of this disclosure is formed from a liquid crystal alignment agent prepared as described above. The liquid crystal element of this disclosure comprises a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operating mode of the liquid crystal in the liquid crystal element is not particularly limited and can be applied to various modes such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe Field Switching) type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured by a method including, for example, the following steps 1 to 3. In step 1, the substrate used differs depending on the desired operating mode. Steps 2 and 3 are common to each operating mode.

[0115] <Step 1: Formation of the coating> First, a liquid crystal alignment agent is applied to the substrate, and preferably the applied surface is heated to form a coating on the substrate. For example, transparent substrates made of glass such as float glass or soda glass, or resins such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin) can be used as the substrate. As the transparent conductive film provided on one surface of the substrate, NESA films (registered trademark of PPG, Inc., USA) made of tin oxide (SnO2), ITO films made of indium oxide-tin oxide (In2O3-SnO2), etc., can be used. When manufacturing TN, STN, or VA type liquid crystal elements, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS type liquid crystal elements, a substrate with comb-shaped patterned electrodes and a counter substrate without electrodes are used. The liquid crystal alignment agent is applied to the substrate on the electrode formation surface, preferably by offset printing, flexographic printing, spin coating, roll coating, or inkjet printing.

[0116] After applying the liquid crystal alignment agent, preheating (pre-bake) is preferably performed to prevent dripping of the applied liquid crystal alignment agent. The pre-bake temperature is preferably 30 to 200°C, and the pre-bake time is preferably 0.25 to 10 minutes. Subsequently, a firing (post-bake) process is performed to further remove the solvent. The firing temperature (post-bake temperature) at this time is preferably 80 to 250°C, more preferably 80 to 200°C. The post-bake time is preferably 5 to 200 minutes. The film thickness of the film formed in this way is preferably 0.001 to 1 μm.

[0117] <Step 2: Orientation Treatment> When manufacturing TN, STN, IPS, or FFS type liquid crystal elements, a process (alignment treatment) is performed to impart liquid crystal alignment ability to the coating film formed in step 1 above. This imparts the liquid crystal molecule alignment ability to the coating film, making it a liquid crystal alignment film. As an alignment treatment, methods such as rubbing, in which the coating film formed on the substrate is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or photo-alignment, in which light is irradiated onto the coating film formed on the substrate to impart liquid crystal alignment ability to the coating film, can be used. On the other hand, when manufacturing vertical alignment (VA) type liquid crystal elements, the coating film formed in step 1 above can be used as is as a liquid crystal alignment film, but an alignment treatment may be applied to the coating film to further enhance its liquid crystal alignment ability. A liquid crystal alignment film suitable for vertical alignment type liquid crystal elements is also suitable for PSA type liquid crystal elements.

[0118] In the photo-alignment process, light irradiation can be performed by methods such as irradiating the coating film after the post-bake process, irradiating the coating film after the pre-bake process but before the post-bake process, or irradiating the coating film while it is being heated in at least one of the pre-bake or post-bake processes. As radiation to irradiate the coating film, for example, ultraviolet light and visible light including light with wavelengths of 150 to 800 nm can be used. Preferably, ultraviolet light including light with wavelengths of 200 to 400 nm is used. If the radiation is polarized, it may be linearly polarized or partially polarized. If the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. In the case of unpolarized radiation, the irradiation direction should be oblique.

[0119] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The radiation dose to the substrate surface is preferably 400 to 50,000 J / m². 2 And more preferably 1,000 to 20,000 J / m 2In addition, after light irradiation to impart orientation ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or a mixture thereof, or the substrate may be heated.

[0120] <Step 3: Liquid Crystal Cell Construction> Two substrates with liquid crystal alignment films formed on them as described above are prepared, and a liquid crystal cell is manufactured between the two substrates so that liquid crystal is arranged adjacent to the liquid crystal alignment film. To manufacture the liquid crystal cell, for example, two substrates are placed opposite each other with a gap in between so that the liquid crystal alignment films face each other, the periphery of the two substrates is bonded together with a sealant, and liquid crystal is injected and filled into the cell gap surrounded by the substrate surface and the sealant, sealing the injection hole, or an ODF method can be used. As the sealant, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as spacers can be used. As the liquid crystal, nematic liquid crystal and smectic liquid crystal can be used, and among these, nematic liquid crystal is preferred. In PSA mode, after the construction of the liquid crystal cell, a voltage is applied between the conductive films of the pair of substrates, and the liquid crystal cell is irradiated with light.

[0121] PSA-type liquid crystal elements can be manufactured by a method that includes the following steps. A step of forming a coating film by applying the liquid crystal alignment agent of this disclosure onto the conductive film of each of a pair of substrates having a conductive film. A process for constructing a liquid crystal cell by arranging a pair of substrates coated with a liquid crystal alignment agent so that the coating films face each other with a liquid crystal layer in between. • A process of applying a voltage between conductive films and irradiating a liquid crystal cell with light.

[0122] Specifically, a liquid crystal cell is constructed in the same manner as in steps 1 to 3 above, except that a photopolymerizable monomer is injected or dropped together with the liquid crystal between a pair of substrates having a conductive film. Conventionally known compounds can be used as the photopolymerizable monomer injected or dropped together with the liquid crystal. Preferably, it is a polyfunctional (meth)acrylic monomer.

[0123] In the manufacturing of PSA-type liquid crystal elements, after constructing the liquid crystal cell, a voltage is applied between the conductive films of a pair of substrates, and the liquid crystal cell is irradiated with light. The applied voltage can be, for example, 5 to 50 V DC or AC. As the irradiated light, ultraviolet light and visible light including wavelengths of 150 to 800 nm can be used. Of these, ultraviolet light including wavelengths of 300 to 400 nm is preferred. As the light source for the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. The amount of light irradiated is preferably 1,000 to 200,000 J / m 2 More preferably, 1,000 to 100,000 J / m 2 That is the case.

[0124] For each mode of liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as needed to form a liquid crystal element. Examples of polarizing plates include a polarizing plate 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 a polarizing plate made of the H film itself.

[0125] The liquid crystal elements of this disclosure can be effectively applied to a variety of uses. Specifically, they can be used, for example, in various display devices such as watches, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, as well as in dimming devices, phase difference films, and the like.

[0126] According to this disclosure, the following means are provided: [Method 1] A liquid crystal alignment agent comprising a polymer [P] selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, having at least one specific structure [S] selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure, or a liquid crystal alignment agent comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and a compound [A] having the specific structure [S] (excluding polymer [P]), and further comprising at least one compound [D1] selected from the group consisting of a compound represented by the following formula (1), a compound represented by formula (2), a compound represented by formula (3), and a compound represented by formula (4). [Method 2] The liquid crystal alignment agent according to [Method 1], wherein the compound [A] has a total of two or more crosslinkable groups. [Method 3] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer [P] contains 2 to 45 mol% of structural units derived from monomers having the specific structure [S] relative to the total amount of structural units derived from monomers constituting the polymer [P]. [Method 4] A liquid crystal alignment agent according to any one of [Method 1] to [Method 3], wherein the specific structure [S] of the polymer [P] is represented by formula (s-1), formula (s-2), formula (s-3), or formula (s-4). [Method 5] The liquid crystal alignment agent according to any one of [Method 1] to [Method 4], wherein the content ratio of compound [A] is 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent. [Method 6] The liquid crystal alignment agent according to any one of [Method 1] to [Method 5], wherein the content of compound [D1] is 1 to 80% by mass relative to the total amount of solvent contained in the liquid crystal alignment agent. [Method 7] A liquid crystal alignment agent according to any one of [Method 1] to [Method 6], further comprising at least one compound [D2] selected from the group consisting of aprotic polar solvents and phenolic solvents. [Method 8] The liquid crystal alignment agent according to [Method 7], wherein the content of compound [D2] is 25% by mass or more relative to the total amount of solvent contained in the liquid crystal alignment agent. [Method 9] A liquid crystal alignment agent according to any one of [Method 1] to [Method 8], comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer, which does not have the specific structure [S]. [Method 10] A liquid crystal alignment film formed using a liquid crystal alignment agent described in any of [Method 1] to [Method 9]. [Method 11] A liquid crystal element comprising the liquid crystal alignment film described in [Method 10]. [Examples]

[0127] The present invention will be described in detail below with reference to examples, but it is not limited to the following examples.

[0128] In the following example, the imidization rate of polyimide was measured by the following method. <Imidification rate of polyimides> A polyimide solution was added to pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. Then it was dissolved in deuterated dimethyl sulfoxide, with tetramethylsilane as the reference substance, at room temperature. 1 1H-NMR measurements were performed. 1 The imidization rate [%] was determined from the 1H-NMR spectrum using the following formula (1). Imidization rate [%] = (1 - (β 1 / ( β 2 ×α)))×100 …(1) (In formula (1), β 1 This represents the peak area originating from the proton of the NH group, appearing around a chemical shift of 10 ppm, and β 2 α represents the peak area derived from other protons, and α is the ratio of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0129] The abbreviations for the compounds used in the examples below are shown below. For convenience, the compound represented by formula (X) may be simply referred to as "compound (X)" below.

[0130] <Tetracarboxylic acid dianhydride> [ka]

[0131] <Diamine> [ka] [ka] [ka] [ka] [ka]

[0132] <Other monomers and reactive compounds> [ka] [ka]

[0133] <Additives> [ka]

[0134] <Solvent> NMP:N-methyl-2-pyrrolidone NEP:N-ethyl-2-pyrrolidone GBL: γ-Butyrolactone [ka]

[0135] <Synthesis of polymers> 1. Synthesis of polyamic acids [Synthesis Example 1] 100 moles of compound (CB-1) as a tetracarboxylic dianhydride, and 70 moles of compound (DB-2) and 30 moles of compound (DE-2) as diamine compounds were dissolved in N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at 60°C for 6 hours to obtain a solution containing 20% ​​by mass of polyamic acid (referred to as polymer (p-1)).

[0136] [Synthesis Examples 2, 4-13, 15 and 16] The same procedure as in Synthesis Example 1 was carried out, except that the types and amounts of tetracarboxylic dianhydride and diamine compounds used were changed as shown in Table 1, to obtain polyamic acids (these were designated as polymers (p-2), (p-4) to (p-13), (p-15), and (p-16)).

[0137] 2. Synthesis of polyimides [Synthesis Example 3] Except for changing the types and amounts of tetracarboxylic dianhydride and diamine compounds used as shown in Table 1, the same procedure as in Synthesis Example 1 was carried out to obtain a solution containing 20% ​​by mass of polyamic acid. Next, NMP was added to the obtained polyamic acid solution to make a 10% by mass solution of polyamic acid, and pyridine and acetic anhydride were added to carry out a dehydration and cyclization reaction at 80°C for 4 hours. After the dehydration and cyclization reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide (referred to as polymer (p-3)) with an imidization rate of approximately 65%.

[0138] [Synthesis Example 14] The procedure was the same as in Synthesis Example 3, except that the types and amounts of tetracarboxylic dianhydride and diamine compounds used were changed as shown in Table 1, to obtain a polyimide with an imidization rate of approximately 60% (this was designated as polymer (p-14)).

[0139] In Table 1, the values ​​for tetracarboxylic dianhydrides (acid dianhydrides 1-4) represent the molar ratio of each compound to 100 moles of the total amount of tetracarboxylic dianhydrides used in the synthesis of the polymer. The values ​​for diamine compounds (diamines 1-6) represent the molar ratio of each compound to 100 moles of the total amount of diamine compounds used in the synthesis of the polymer.

[0140] [Table 1]

[0141] 3. Synthesis of polyorganosiloxanes [Synthesis Example 17] 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (S-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were charged into a 1000 mL three-necked flask and mixed at room temperature. Then, 100 g of deionized water was added dropwise from a dropping funnel over 30 minutes, and the reaction was carried out at 80°C for 6 hours while mixing under reflux. After the reaction was complete, the organic layer was removed and washed with 0.2% by mass aqueous solution of ammonium nitrate until the water after washing was neutral, and then the solvent and water were removed under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by mass solution of polymer (ESSQ-1), which is a polyorganosiloxane having epoxy groups. In a 500 mL three-necked flask, 3.10 g of compound (c-1) (20 mol% relative to the amount of epoxy groups in polymer (ESSQ-1)), 3.24 g of compound (c-2) (10 mol% relative to the amount of epoxy groups in polymer (ESSQ-1)), 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added, and the mixture was stirred at 90°C for 18 hours. After cooling to room temperature, the solution was subjected to 10 separate washes with distilled water. The organic layer was then collected, concentrated and diluted twice using a rotary evaporator, and then adjusted using NMP to a solid content concentration of 10% by mass to obtain an NMP solution of polyorganosiloxane (referred to as polymer (PSQ-1)).

[0142] 4. Synthesis of Styrene-Maleimide Copolymer [Synthesis Example 18] Under nitrogen, 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and 2.26 g of compound (M-4) as polymerization monomers, 0.39 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 mL of NMP as a solvent were added to a 100 mL two-neck flask, and polymerization was carried out at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum dried at room temperature for 8 hours to obtain a styrene-maleimide copolymer (designated as polymer (MI-1)).

[0143] [Synthesis Example 19] The same procedure as in Synthesis Example 18 was carried out except that 8.10 g of compound (M-5), 5.50 g of compound (M-6), 7.70 g of compound (M-7), and 3.10 g of compound (M-8) were used as polymerization monomers to obtain a styrene-maleimide copolymer (designated as polymer (MI-2)).

[0144] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: Rubbing Horizontal Type Liquid Crystal Display Element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 100 parts by mass of the polymer (p-1) obtained in Synthesis Example 1 was diluted with NMP, butyl cellosolve (BC), and compound (SD-1) to obtain a solution having a solvent composition of NMP / BC / SD-1 = 45 / 45 / 10 (mass ratio) and a solid content concentration of 3.5 mass%. A liquid crystal alignment agent (AL-1) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

[0145] 2. Manufacture of Rubbing Horizontal Type Liquid Crystal Display Element The liquid crystal alignment agent (AL-1) prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. Then, it was heated in an oven with nitrogen purging at 230°C for 1 hour to form a coating with a thickness of 0.1 μm. This coating was then rubbed using a rubbing machine with a roll wrapped in rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / second, and a pile insertion length of 0.1 mm. After that, it was ultrasonically cleaned in ultrapure water for 1 minute, and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. By repeating this series of operations, a pair (2 sheets) of substrates with a liquid crystal alignment film was prepared. Next, an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was screen printed onto the outer circumference of one of the substrates having a liquid crystal alignment film. Then, the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, and they were pressed together so that the projection direction of the ultraviolet optical axis of each substrate onto the substrate surface was horizontal. The adhesive was then heat-cured at 150°C for 1 hour. Next, positive-type liquid crystal (Merck, MLC-7028-100) was filled into the gap between the substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with epoxy adhesive. Furthermore, to remove the flow orientation during liquid crystal injection, it was heated at 130°C and then slowly cooled to room temperature. Next, polarizing plates were bonded to both outer surfaces of the substrates so that their polarization directions were orthogonal to each other and formed a 90° angle with the projection direction of the ultraviolet optical axis of the liquid crystal alignment film onto the substrate surface, thereby manufacturing a liquid crystal display element.

[0146] 3. Evaluation of panel transmittance The absorption spectrum in the ultraviolet and visible light region was measured for the liquid crystal display element fabricated in step 2 above using an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, product name "V-670"). The incident angle on the liquid crystal display element was set to 0°. A transmittance of 89% or higher in the wavelength range of 380 to 800 nm was rated as "Good (○)", 88% or higher but less than 89% was rated as "Acceptable (△)", and less than 88% was rated as "Poor (×)". As a result, the panel transmittance of this example was evaluated as "Good (○)".

[0147] 4. Evaluation of in-plane uniformity The liquid crystal alignment agent (AL-1) prepared in step 1 above was stored in a refrigerator at 4°C for one month. After returning the liquid crystal alignment agent to room temperature, its in-plane uniformity was evaluated. For the evaluation, the liquid crystal alignment agent was continuously coated onto an ITO substrate using a JET-CM continuous inkjet printer (manufactured by Kishu Giken Kogyo Co., Ltd.) at a volume that resulted in a dry film thickness of 0.1 μm. The time required from the start of application of the liquid crystal alignment agent to the completion of coating the entire substrate and baking was 10 minutes. The resulting alignment film coated substrate was pre-baked on a hot plate at 80°C for 1 minute, and then post-baked at 230°C for 30 minutes in a clean oven under a nitrogen atmosphere. After that, the peripheral and central parts of the liquid crystal alignment film were observed with a 20x microscope. At this time, if there were no pinholes or coating irregularities (film thickness irregularities, etc.), it was judged as "good (○)", and if at least one of the pinholes or coating irregularities was observed, it was judged as "poor (×)". As a result, the in-plane uniformity of this embodiment was rated as "good (○)".

[0148] 5. Evaluation of contact hole coating properties The liquid crystal alignment agent (AL-1) prepared in step 1 above was stored in a refrigerator at 4°C for one month. After returning the liquid crystal alignment agent to room temperature, it was loaded into a Shibaura inkjet device, and inkjet coating was performed on a glass substrate having contact holes (C / H) and an ITO layer. The contact holes were formed by applying a photosensitive resin to the glass substrate to form a resin layer with a thickness of 3.5 μm, exposing it through a mask to create a hole diameter of 25 μm and an inter-hole distance of 200 μm, and then developing the material. After the contact holes were formed, the ITO layer was formed on the contact hole formation surface of the glass substrate by sputtering. After applying the liquid crystal alignment agent (AL-1), the material was pre-baked on a hot plate at 80°C for 1 minute. Subsequently, it was heated in an oven with nitrogen purging at 200°C for 1 hour to form a liquid crystal alignment film with a thickness of 0.1 μm. 200 of these liquid crystal alignment films were visually counted using a scanning electron microscope (SEM) at 50x magnification, and the coating performance was evaluated by the percentage of contact holes where the liquid crystal was properly coated without any defects (coating rate α[%]). α[%] = [(Number of contact holes successfully coated) / 200] × 100 The evaluation criteria were as follows: a coating rate α of 95% or higher was rated as "exceptionally good (◎)", 90% or more but less than 95% was rated as "good (○)", 80% or more but less than 90% was rated as "acceptable (△)", and less than 80% was rated as "poor (×)". As a result, the contact hole coating performance of this example was rated as "exceptionally good (◎)".

[0149] [Example 16] Except for the changes in the compound composition and solvent composition as shown in Table 2, the liquid crystal alignment agent (AL-16) was prepared with the same solid content concentration as in Example 1. Using this liquid crystal alignment agent, the in-plane uniformity and contact hole coating properties were evaluated in the same manner as in Example 1, and a rubbing horizontal liquid crystal display element was manufactured to evaluate the panel transmittance. The evaluation results are shown in Table 2.

[0150] [Example 2: PSA-type liquid crystal display element] 1. Preparation of liquid crystal alignment agent A solution containing 100 parts by mass of polymer (p-7) obtained in Synthesis Example 7 and 20 parts by mass of compound (BD-1) were diluted with NMP, BC, and compound (SP-1) to prepare a solution with a solvent composition of NMP / BC / SP-1 = 25 / 25 / 50 (mass ratio) and a solid content concentration of 3.5% by mass. Liquid crystal alignment agent (AL-2) was prepared by filtering this solution through a pore size filter of 0.2 μm.

[0151] 2. Preparation of liquid crystal composition To 10 g of nematic liquid crystal (Merck MLC-6608 negative liquid crystal), 5% by mass of a liquid crystalline compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added and mixed to obtain liquid crystal composition LC1. [ka]

[0152] 3. Manufacturing of PSA-type liquid crystal display elements The liquid crystal alignment agent (AL-2) prepared in step 1 above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner. After pre-baking on an 80°C hot plate for 1 minute, the solvent was removed by heating in a nitrogen-purged oven at 200°C for 1 hour to form a coating film (liquid crystal alignment film) with a thickness of 0.08 μm. This coating film was then rubbed using a rubbing machine with a roll wrapped in rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / second, and a pile insertion length of 0.1 mm. Subsequently, ultrasonic cleaning was performed in ultrapure water for 1 minute, and then drying in a 100°C clean oven for 10 minutes to obtain a substrate with a liquid crystal alignment film. This operation was repeated to obtain a pair (2 sheets) of substrates with a liquid crystal alignment film. This rubbing process was a weak rubbing process performed to control the tilting of the liquid crystals and to perform alignment division in a simple manner. An epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was screen printed onto the outer periphery of one of the substrates having a liquid crystal alignment film. Then, the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, overlapped, and pressed together. The adhesive was then heat-cured at 150°C for 1 hour. Next, the liquid crystal composition LC1 was filled into the gap between the substrates through the liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy adhesive, and then, to remove the flow orientation during liquid crystal injection, it was heated at 150°C for 10 minutes and then slowly cooled to room temperature. Next, a 10V AC current with a frequency of 60Hz is applied between the electrodes of the obtained liquid crystal cell, and while the liquid crystal is in operation, ultraviolet light of 50,000 J / m² is irradiated using an ultraviolet irradiation device with a metal halide lamp as the light source. 2It was irradiated with the irradiation dose. This irradiation dose is a value measured using a light meter measured based on a wavelength of 365 nm. Thereby, a PSA type liquid crystal display element was manufactured.

[0153] 4. Evaluation Regarding the liquid crystal aligning agent (AL-2) prepared in 1. above and the PSA type liquid crystal display element manufactured in 3. above, evaluation of panel transmittance, in-plane uniformity, and contact hole coating property was performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0154] [Examples 3 to 6, 10 to 14, 17, 19 to 21 and Comparative Examples 1 to 4] Liquid crystal aligning agents (AL-3) to (AL-6), (AL-10) to (AL-14), (AL-17), (AL-19) to (AL-21) and (AR-1) to (AR-4) were prepared at the same solid content concentration as in Example 2, except that the blending composition and solvent composition were changed as shown in Table 2. Further, using each liquid crystal aligning agent, in-plane uniformity and contact hole coating property were evaluated in the same manner as in Example 2, and a PSA type liquid crystal display element was manufactured to evaluate the panel transmittance. The evaluation results are shown in Table 2.

[0155] [Example 7: Optical VA type liquid crystal display element] 1. Preparation of liquid crystal aligning agent A solution containing 100 parts by mass of the polymer (p-9) obtained in Synthesis Example 9 and 30 parts by mass of the compound (AD-1) was diluted with NMP, BC, and the compound (SD-2) to obtain a solution having a solvent composition of NMP / BC / SD-2 = 45 / 20 / 35 (mass ratio) and a solid content concentration of 3.5% by mass. The liquid crystal aligning agent (AL-7) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

[0156] 2. Manufacture of optical VA type liquid crystal display element The liquid crystal alignment agent (AL-7) prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. Then, it was heated in an oven with nitrogen purging at 230°C for 1 hour to form a coating with a thickness of 0.1 μm. Next, the surface of this coating was exposed to polarized ultraviolet light containing a 313 nm emission line at 1,000 J / m using a Hg-Xe lamp and a Gran-Taylor prism. 2 The substrate was irradiated from a direction tilted 40° from the substrate normal to impart liquid crystal alignment capability. The same operation was repeated to create a pair (2 substrates) of substrates with a liquid crystal alignment film. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen printed onto the outer periphery of one of the substrates having a liquid crystal alignment film. Then, the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, and they were pressed together so that the projection direction of the ultraviolet light axis of each substrate onto the substrate surface was opposite parallel. The adhesive was then heat-cured at 150°C for 1 hour. Next, negative liquid crystal (Merck MLC-6608) was filled into the gap between the substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with epoxy adhesive. Furthermore, to remove the flow orientation during liquid crystal injection, it was heated at 130°C and then slowly cooled to room temperature.

[0157] 3. Evaluation The liquid crystal alignment agent (AL-7) prepared in 1. above and the optical VA-type liquid crystal display element manufactured in 3. above were evaluated for panel transmittance, in-plane uniformity, and contact hole coating properties in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0158] [Examples 8, 9, 15, and 18] Liquid crystal alignment agents (AL-8), (AL-9), (AL-15), and (AL-18) were prepared with the same solid content concentrations as in Example 7, except that the compound composition and solvent composition were changed as shown in Table 2. Furthermore, the in-plane uniformity and contact hole coating properties were evaluated using each liquid crystal alignment agent in the same manner as in Example 7, and a VA-type optical liquid crystal display element was manufactured to evaluate panel transmittance. The evaluation results are shown in Table 2.

[0159] [Table 2]

[0160] In Table 2, the "Overall Evaluation" was determined using the following criteria: "○" if all three evaluation items received a good (○) or higher rating; "△" if none of the three evaluation items received a poor (×) rating, but one or more received a good (△) rating; and "×" if any one of the three evaluation items received a poor (×) rating.

[0161] As shown in Table 2, the liquid crystal alignment agents of Examples 1 to 21 were evaluated as particularly good (◎), good (○), or acceptable (△) in terms of panel transmittance, in-plane uniformity, and contact hole coating properties, indicating a good balance of various properties. In contrast, Comparative Examples 1 to 3, which did not contain either polymer [P] or compound [A] in the liquid crystal alignment agent, were evaluated as "poor (×)" in one or more of the panel transmittance, in-plane uniformity, or contact hole coating properties. Furthermore, Comparative Example 4, which did not contain compound [D1] in the solvent, had "poor (×)" contact hole coating properties.

[0162] From the above results, it has become clear that the liquid crystal alignment agent of this disclosure can be used to obtain a liquid crystal display element with excellent coatability and panel transmittance.

Claims

1. It contains a polymer [P] having at least one specific structure [S] selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and selected from the group consisting of a naphthalene ring structure, a fluorene ring structure, and a triazine ring structure, or it contains at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, and a compound [A] having the specific structure [S] (excluding polymer [P]), Furthermore, a liquid crystal alignment agent containing at least one compound [D1] selected from the group consisting of a compound represented by formula (1), a compound represented by formula (2), a compound represented by formula (3), and a compound represented by formula (4). 【Chemistry 1】 (In formula (1), R １１ and R １２ Each of these is an alkyl group having 1 to 3 carbon atoms. １３ This is a monovalent group in which an alkyl group having 1 to 6 carbon atoms or some of the hydrogen atoms in an alkyl group having 1 to 6 carbon atoms are replaced by hydroxyl groups. In formula (2), R ２１ R is an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 1 to 6 carbon atoms. ２２ R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ２３ R is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxyalkyl group having 1 to 6 carbon atoms. However, R ２２ and R ２３ They do not simultaneously become hydrogen atoms. In formula (3), R ３１ and R ３２ are each independently an alkyl group having 1 to 6 carbon atoms, or R ３１ and R ３２ are combined with each other, and R ３１ and R ３２ are bonded to -CH ２ -CO-CH ２ - to represent a ring structure formed together. In formula (4), R ４１ R is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an acetyl group. ４２ This is an alkanediyl group having 2 to 4 carbon atoms, and multiple R ４２ They are either identical or different from each other. ４３ (where n is an alkyl group or acetyl group having 1 to 6 carbon atoms; n is an integer between 2 and 4.)

2. The liquid crystal alignment agent according to claim 1, wherein the compound [A] has a total of two or more crosslinkable groups.

3. The liquid crystal alignment agent according to claim 1, wherein the polymer [P] contains 2 to 45 mol% of structural units derived from monomers having the specific structure [S] relative to the total amount of structural units derived from monomers constituting the polymer [P].

4. The liquid crystal alignment agent according to claim 1, wherein the specific structure [S] of the polymer [P] is represented by the following formula (s-1), formula (s-2), formula (s-3), or formula (s-4). 【Chemistry 2】 (In equations (s-1), (s-2), (s-3), and (s-4), Y １ ~Y ６ Each of these is independently a halogen atom, a hydroxyl group, or a monovalent organic group. r1 is an integer from 0 to 6. r2 and r3 are independently integers from 0 to 8. r4 and r5 are independently integers from 0 to 4. r6 is 0 or 1. (* indicates a bond with an atom constituting the main chain of the polymer.)

5. The liquid crystal alignment agent according to claim 1, wherein the content of compound [A] is 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of polymer components contained in the liquid crystal alignment agent.

6. The liquid crystal alignment agent according to claim 1, wherein the content of the compound [D1] is 1 to 80% by mass relative to the total amount of solvent contained in the liquid crystal alignment agent.

7. The liquid crystal alignment agent according to claim 1, further comprising at least one compound [D2] selected from the group consisting of aprotic polar solvents and phenolic solvents.

8. The liquid crystal alignment agent according to claim 7, wherein the content of the compound [D2] is 25% by mass or more relative to the total amount of solvent contained in the liquid crystal alignment agent.

9. The liquid crystal alignment agent according to claim 1, comprising at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer, which does not have the specific structure [S].

10. A liquid crystal alignment film formed using the liquid crystal alignment agent described in any one of claims 1 to 9.

11. A liquid crystal element comprising the liquid crystal alignment film described in claim 10.

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