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

Abstract

The present application provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. A polymeric component is at least one of (I) and (II): (I) containing a polymer [P] including a structural unit (A) derived from a diamine having a partial structure represented by formula (1) or a compound having a polymerizable unsaturated bond having a partial structure represented by formula (1), and a structural unit (B) having at least one selected from the group consisting of a nitrogen-containing heterocyclic structure and a partial structure represented by formula (2); and (II) containing a polymer [P1] including a structural unit (A), and a polymer [P2] including a structural unit (B).A 1 R is a monovalent chain hydrocarbon group having 5 or more carbon atoms, etc. 1 R is a hydrogen atom or a monovalent organic group. 2 R is a hydrogen atom or a monovalent organic group. 3 R is a hydrogen atom or a monovalent organic group.

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] Liquid crystal elements are used in a wide range of devices and applications, from large LCD TVs to small display devices such as smartphones. With the increasing versatility of these liquid crystal elements, there is a demand for higher quality liquid crystal elements. Various properties of liquid crystal alignment films that control the orientation of liquid crystal molecules have been explored in liquid crystal elements (for example, see Patent Document 1).

[0003] Patent Document 1 discloses that a liquid crystal alignment agent contains a polymer having a structure derived from a diamine having a carboxyl group and a polymer having a structure derived from a diamine having a tertiary nitrogen atom, thereby improving the friction resistance of the coating and the electrical properties of the liquid crystal alignment film.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2015-92222 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] In the liquid crystal alignment agent of Patent Document 1, it is believed that the charge transfer efficiency in the liquid crystal alignment film is well achieved through the acid-base interaction between the carboxyl groups of the polymer and the tertiary nitrogen atoms, thereby suppressing the accumulation of residual charge in the liquid crystal element caused by the application of DC voltage. However, in this case, there is a tendency for the polymer to easily aggregate due to the acid-base interaction between the carboxyl groups and the tertiary nitrogen atoms, which raises concerns about reduced coatability.

[0009] The present invention was made in view of the above-mentioned problems, and its main objective is to provide a liquid crystal alignment agent for liquid crystal elements that has high solubility of polymers, excellent coatability, and can suppress the accumulation of residual charge.

[0010] [Technical means to solve the problem]

[0011] The inventors conducted diligent research to solve the aforementioned problems, and discovered that these problems can be solved by using polymers having specific structural units, thus completing the present invention. Specifically, the following means are provided according to the present invention.

[0012] <1> A liquid crystal alignment agent comprising a polymeric component, said polymeric component being at least one of the following (I) and (II):

[0013] (I) A polymer [P] comprising a structural unit (A) and a structural unit (B), wherein the structural unit (A) is derived from a diamine having a partial structure represented by the following formula (1) or a compound having a partial structure represented by the following formula (1), and the structural unit (B) has at least one selected from the group consisting of a nitrogen-containing heterocyclic structure and a partial structure represented by the following formula (2);

[0014] (II) Contains an aggregate [P1] containing the structural unit (A) and an aggregate [P2] containing the structural unit (B).

[0015] [Chemistry 1]

[0016]

[0017] (In formula (1), A) 1 A monovalent chain hydrocarbon group or alicyclic hydrocarbon group having 5 or more carbon atoms, or a monovalent group having 3 or more carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group or alicyclic hydrocarbon group. 1 "This indicates a bond formed with a carbon atom."

[0018] [Chemistry 2]

[0019]

[0020] (In equation (2), R) 1 It can be a hydrogen atom or a monovalent organic group. 2 "and"* 3 "These represent the bonds formed with carbon atoms."

[0021] <1-1> A liquid crystal alignment agent comprising a polymer [P] including structural unit (A) and structural unit (B), wherein the structural unit (A) is derived from a diamine having a partial structure represented by the formula (1), and the structural unit (B) has at least one selected from the group consisting of a nitrogen-containing heterocyclic structure and a partial structure represented by the formula (2).

[0022] <2> A liquid crystal alignment film formed using the liquid crystal alignment agent of <1>.

[0023] <3> A liquid crystal element comprising the liquid crystal alignment film of <2>.

[0024] [The effects of the invention]

[0025] The liquid crystal alignment agent of the present invention exhibits high solubility and excellent coatability of the polymer. Furthermore, the liquid crystal alignment agent according to the present invention enables the acquisition of liquid crystal elements in which the accumulation of residual charge is suppressed. Detailed Implementation

[0026] The following describes the components contained in the liquid crystal alignment agent disclosed herein, as well as other components that may be arbitrarily added as needed.

[0027] Furthermore, in this specification, the term "hydrocarbon group" encompasses chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that consists only of a chain structure and does not contain a ring structure. It can be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as its ring structure and does not contain an aromatic ring structure. It does not necessarily have to consist solely of an alicyclic hydrocarbon structure; it also includes groups with a chain structure in a portion thereof. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. It does not necessarily have to consist solely of an aromatic ring structure; it may also contain a chain structure or an alicyclic hydrocarbon structure in a portion thereof. "Aromatic ring" encompasses both aromatic hydrocarbon rings and aromatic heterocycles. "Organic group" refers to a group of atoms formed by removing any hydrogen atoms from a carbon-containing compound (i.e., an organic compound).

[0028] Liquid crystal alignment agent

[0029] The liquid crystal alignment agent disclosed herein is a polymer composition containing polymeric components. The polymeric components satisfy at least one of (I) and (II) below.

[0030] (I) Containing a polymer [P], said polymer [P] comprising: a structural unit (hereinafter referred to as structural unit (A)) derived from a diamine having a partial structure represented by the following formula (1) or a compound having a partial structure represented by the following formula (1); and a structural unit (hereinafter referred to as structural unit (B)) having at least one of the group consisting of a nitrogen-containing heterocyclic structure and a partial structure represented by the following formula (2).

[0031] (II) Contains an aggregate [P1] containing structural unit (A) and an aggregate [P2] containing structural unit (B).

[0032] [Chemistry 3]

[0033]

[0034] (In formula (1), A) 1 A monovalent chain hydrocarbon group or alicyclic hydrocarbon group having 5 or more carbon atoms, or a monovalent group having 3 or more carbon atoms with -O- between carbon-carbon bonds in the chain hydrocarbon group or alicyclic hydrocarbon group. 1 "This indicates a bond formed with a carbon atom."

[0035] [Chemistry 4]

[0036]

[0037] (In equation (2), R) 1 It can be a hydrogen atom or a monovalent organic group. 2 "and"* 3 "These represent the bonds formed with carbon atoms."

[0038] Hereinafter, the form of (I) as the first embodiment will be described first, and the form of (II) as the second embodiment will be described next. In addition, the liquid crystal alignment agent of this disclosure may also satisfy both (I) and (II). That is, the liquid crystal alignment agent of this disclosure may also include polymer [P], polymer [P1] and polymer [P2].

[0039] [First Implementation]

[0040] The liquid crystal alignment agent of the first embodiment contains a polymer [P] comprising a structural unit (A) and a structural unit (B), wherein the structural unit (A) is derived from a monomer having a partial structure represented by the following formula (1), and the structural unit (B) has at least one selected from the group consisting of a nitrogen-containing heterocyclic structure and a partial structure represented by the following formula (2). The monomer constituting the structural unit (A) is a diamine or a compound containing polymerizable unsaturated bonds.

[0041] <Aggregate [P]>

[0042] • Structural Unit (A)

[0043] The partial structure represented by equation (1) is heated (post-baked) during film formation, and A 1 Detachment occurs, generating a carboxyl group. In formula (1), when A... 1 When the hydrocarbon group is a monovalent chain with 5 or more carbon atoms, the chain group can be linear or branched. From the viewpoint of obtaining a polymer with excellent solubility, when A 1 When the hydrocarbon group is a chain-like hydrocarbon group, the number of carbon atoms in the chain-like hydrocarbon group is 5 or more. Furthermore, from the viewpoints of achieving good in-plane uniformity of the liquid crystal alignment film and reducing residual charge accumulation in the liquid crystal element, A 1 When the group is a chain-like hydrocarbon group, the number of carbon atoms is preferably 20 or less, more preferably 15 or less, and even more preferably 12 or less. When A 1 When it is a chain hydrocarbon group, A exhibits good thermal descaling properties. 1 Preferably alkyl, and particularly preferably tertiary alkyl.

[0044] When A 1 When the alicyclic hydrocarbon group has 5 or more carbon atoms, the alicyclic hydrocarbon group may be saturated or unsaturated, but is preferably saturated. When A 1When the alicyclic hydrocarbon group is used, from the viewpoint of obtaining a polymer exhibiting good solubility, the alicyclic hydrocarbon group has 5 or more carbon atoms, preferably 6 or more. Furthermore, from the viewpoint of achieving good in-plane uniformity of the liquid crystal alignment film and reducing the charge accumulated in the liquid crystal element, A 1 When the group is an alicyclic hydrocarbon group, the number of carbon atoms is preferably 20 or less, and more preferably 15 or less.

[0045] When A in the above formula (1) 1 When the hydrocarbon group is a monovalent chain hydrocarbon group with 5 or more carbon atoms or an alicyclic hydrocarbon group, the partial structure represented by the formula (1) is preferably the partial structure represented by the formula (Y-1) below, in terms of good thermal descaling properties.

[0046] [Chemistry 5]

[0047]

[0048] (In formula (Y-1), R) 3 and R 4 Each is independently an alkyl group, or represents R. 3 With R 4 Combine with R 3 and R 4 A ring structure with 4 or more carbon atoms formed by the bonded carbon atoms. R 5 It is an alkyl group. Wherein, in R... 3 and R 4 When both are methyl, R 5 It has 2 or more carbon atoms. "*" indicates a bond.

[0049] As specific examples of the partial structure represented by the above formula (Y-1), the structures represented by the following formulas (M-1) to (M-20) can be listed respectively.

[0050] [Chemistry 6]

[0051]

[0052] (In formulas (M-1) to (M-20), "*" indicates a bond formed with a carbon atom.)

[0053] When A 1 When a monovalent group with 3 or more carbon atoms (-O-) exists between carbon-carbon bonds in a chain-like hydrocarbon group or an alicyclic hydrocarbon group, groups having an acetal structure of a carboxylic acid or a ketal structure of a carboxylic acid can be listed as the group represented by the formula (1). In A 1 From the viewpoint of achieving good in-plane uniformity of the liquid crystal alignment film and reducing the charge accumulated in the liquid crystal element, the number of carbons having a -O- monovalent group between the carbon-carbon bonds of the chain hydrocarbon group or alicyclic hydrocarbon group is preferably 20 or less, more preferably 15 or less.

[0054] As acetal ester structures of carboxylic acids, examples include those represented by formulas (X-1) and (X-2) respectively.

[0055] [Chemistry 7]

[0056]

[0057] (In formula (X-1), R) 4 and R 5 Each is independently an alkyl group having 1 to 15 carbon atoms, or a cycloalkyl group having 3 to 15 carbon atoms. In formula (X-2), r is an integer from 2 to 10. "*" indicates a bond formed with a carbon atom.

[0058] Specific examples of the group represented by formula (X-1) include: 1-methoxyethoxycarbonyl, 1-ethoxyethoxycarbonyl, 1-propoxyethoxycarbonyl, 1-butoxyethoxycarbonyl, 1-cyclopentyloxyethoxycarbonyl, 1-cyclohexyloxyethoxycarbonyl, 1-norbornyloxyethoxycarbonyl, (cyclohexyl)(methoxy)methoxycarbonyl, (cyclohexyl)(ethoxy)methoxycarbonyl, etc.

[0059] Examples of the groups represented by formula (X-2) include 2-tetrahydrofuranyloxycarbonyl and 2-tetrahydropyranyloxycarbonyl.

[0060] Examples of ketal ester structures of carboxylic acids include those represented by formulas (X-3) to (X-5).

[0061] [Chemistry 8]

[0062]

[0063] (In formula (X-3), R) 6 R is an alkyl group having 1 to 12 carbon atoms. 7 and R 8 Each is independently an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms. In formula (X-4), R 9 It is an alkyl group having 1 to 12 carbon atoms. t is an integer from 2 to 8. In formula (X-5), R 10 Alkyl groups having 1 to 12 carbon atoms. u is an integer from 2 to 8. "*" indicates a bond formed with a carbon atom.

[0064] Specific examples of the group represented by formula (X-3) include: 1-methyl-1-methoxyethoxycarbonyl, 1-methyl-1-ethoxyethoxycarbonyl, 1-methyl-1-propoxyethoxycarbonyl, 1-methyl-1-butoxyethoxycarbonyl, 1-methyl-1-cyclohexyloxyethoxycarbonyl, 1-methyl-1-norbornyloxyethoxycarbonyl, 1-cyclohexyl-1-methoxyethoxycarbonyl, 1-cyclohexyl-1-propoxyethoxycarbonyl, etc.

[0065] Specific examples of the group represented by formula (X-4) include, for example, 2-(2-methyltetrahydrofuranyl)oxycarbonyl, 2-(2-methyltetrahydropyranyl)oxycarbonyl, etc.

[0066] Examples of the groups represented by formula (X-5) include 1-methoxycyclopentyloxycarbonyl and 1-methoxycyclohexyloxycarbonyl.

[0067] Regarding the liquid crystal alignment agent that can uniformly exhibit the coating properties of the liquid crystal alignment agent, the in-plane uniformity of the liquid crystal alignment film, and the reduction effect of residual charge accumulated in the liquid crystal element, the partial structure represented by formula (1) in structural unit (A) is preferably selected from at least one of the group consisting of the structure represented by formula (Y-1), the acetal structure of carboxylic acid, and the ketal ester structure of carboxylic acid. The bonding bonds in formula (1) (*) 1 Preferably, it is a hydrocarbon structure bonded to a hydrocarbon group or forming a heterocycle, and more preferably, it is bonded to an aromatic hydrocarbon ring.

[0068] Among the monomers constituting structural unit (A), the diamine having a partial structure represented by formula (1) (hereinafter also referred to as the "first monomer") is any compound having a partial structure represented by formula (1) and two primary amino groups, and there is no particular limitation. Examples of first monomers include compounds represented by formula (4-1), compounds represented by formula (4-2), compounds represented by formula (4-3), and compounds represented by formula (4-4).

[0069] [Chemistry 9]

[0070]

[0071] (In equations (4-1) to (4-4), X) 3 and X 5 They are, independently, single bonds, alkyldiyl groups with 1 to 3 carbon atoms, fluoroalkyldiyl groups with 1 to 3 carbon atoms, -O-, -S-, -COO-, -CH2O-, and -NR-, respectively. 11 -or-CONR 11 -. R 11 It consists of hydrogen atoms or alkyl groups having 1 to 3 carbon atoms. X4 It is an alkyldiyl group having 1 to 5 carbon atoms. R 10 A monovalent group formed by substituting at least one hydrogen atom of an alkyl group having 1 to 10 carbon atoms, or the alkyl group having at least one hydrogen atom, with a group represented by formula (1). 1 With A in the above formula (1) 1 (These have the same meaning. m1 is an integer from 1 to 4. m2 is an integer from 0 to 4.)

[0072] In equations (4-1) to (4-4), m1 is preferably 1 or 2, more preferably 1. m2 is preferably 0 to 2, more preferably 0 or 1. Regarding A 1 The above explanation can be cited.

[0073] Among the monomers constituting structural unit (A), compounds containing polymerizable unsaturated bonds having a partial structure represented by formula (1) (hereinafter also referred to as "second monomers") are not particularly limited as long as they have a partial structure represented by formula (1) and polymerizable unsaturated bond groups. Examples of polymerizable unsaturated bond groups that can be included as second monomers include: (meth)acryloyl, maleimide, vinyl (including vinyl groups contained in alkenyl, vinylphenyl, vinyl ether, etc.). Specific examples of second monomers include, for example, compounds represented by formula (6-1), compounds represented by formula (6-2), and compounds represented by formula (6-3).

[0074] [Chemistry 10]

[0075]

[0076] (In equations (6-1) to (6-3), E) 1 It can be a hydrogen atom or a methyl group. E 2 and E 3 Each is an independent divalent hydrocarbon group. A 1 With A in the above formula (1) 1 (These have the same meaning. k is an integer from 1 to 4.)

[0077] In the polymer [P], from the viewpoint of sufficiently improving solubility and sufficiently reducing the accumulation of residual charge in the liquid crystal element, the content ratio of structural unit (A) is preferably 2.5 mol% or more relative to the total amount (100 mol%) of structural units derived from the monomer in the polymer [P]. The content ratio of structural unit (A) is more preferably 5 mol% or more relative to the total amount of structural units derived from the monomer in the polymer [P], and even more preferably 10 mol% or more, and even more preferably 15 mol% or more. Furthermore, from the viewpoint of making the ratio of structural unit (A) to structural unit (B) in the polymer [P] within a preferred range and more efficiently reducing the accumulation of residual charge, when structural unit (A) is a structural unit derived from the first monomer, the content ratio of structural unit (A) is preferably 40 mol% or less relative to the total amount of structural units derived from the monomer in the polymer [P], more preferably 35 mol% or less, even more preferably 30 mol% or less, and even more preferably 25 mol% or less. When the structural unit (A) is a structural unit derived from the second monomer, the content of the structural unit (A) is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, relative to the total amount of structural units derived from the monomer in the polymer [P]. Furthermore, the polymer [P] may contain only one type of structural unit (A), or it may contain two or more types.

[0078] • Structural Unit (B)

[0079] Structural unit (B) has at least one of the group consisting of nitrogen-containing heterocyclic structures and partial structures represented by the formula (2) (hereinafter also referred to as "specific nitrogen-containing structures").

[0080] The nitrogen-containing heterocyclic structure of structural unit (B) can be either an aromatic heterocyclic structure or a non-aromatic heterocyclic structure. Specific examples of nitrogen-containing aromatic heterocyclic structures include structures having a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a quinoline ring, a benzimidazole ring, a carbazole ring, and a pyrazine ring, as well as heterocyclic structures having substituents (e.g., methyl, ethyl, etc.) in these rings. Examples of nitrogen-containing non-aromatic heterocyclic structures include structures having a piperidine ring, a piperazine ring, a morpholine ring, and a hexamethyleneimine ring, as well as heterocyclic structures having substituents (e.g., methyl, ethyl, etc.) introduced into these rings. Preferably, the nitrogen-containing heterocyclic structure of structural unit (B) has at least one structure selected from the group consisting of a pyridine ring, a pyrimidine ring, a pyrazine ring, a piperidine ring, a piperazine ring, a quinoline ring, a benzimidazole ring, and a carbazole ring.

[0081] As part of the structure represented by formula (2), secondary amino and tertiary amino groups can be listed. In formula (2), R1 The monovalent organic group is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent desorbable group that can be desorbed by heat or light (hereinafter also simply referred to as a "desorbable group"). In R 1 When the monovalent hydrocarbon group is a alkyl group, it is preferably an alkyl group with 1 to 3 carbon atoms, a cyclohexyl group, or a phenyl group, and more preferably an alkyl group with 1 to 3 carbon atoms.

[0082] In R 1 In the case of a removable group, the removable group is preferably a monovalent group that can be removed by heat (hereinafter also referred to as a "thermally removable group"), such as carbamate-based protecting groups, amide-based protecting groups, imide-based protecting groups, sulfonamide-based protecting groups, etc. Among these, carbamate-based protecting groups are preferred in terms of high thermal removability, and specific examples include tert-butoxycarbonyl, benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, etc. Among these, tert-butoxycarbonyl (t-Boc(t-butyloxycarbonyl) group) is particularly preferred in terms of excellent thermal removability and the reduction of the amount of deprotected portion remaining in the film.

[0083] R 1 Preferably, it is a hydrogen atom, a monovalent hydrocarbon group having 1 to 12 carbon atoms, or a thermally detachable group; more preferably, it is a hydrogen atom, a monovalent hydrocarbon group having 1 to 6 carbon atoms, or a tert-butoxycarbonyl group. Of these, hydrogen atom, methyl, or ethyl is particularly preferred in terms of further improving the reduction effect of accumulated charge in the liquid crystal element. The two bonds in formula (2) (*) 2 、* 3 Preferably, it is a hydrocarbon structure bonded to a hydrocarbon group or forming a heterocycle, and more preferably, at least one of the two bonds is bonded to an aromatic ring (aromatic hydrocarbon ring or aromatic heterocycle).

[0084] The polymer [P] may have a specific nitrogen-containing structure in the main chain or in the side chain portions. Here, in this specification, the term "main chain" of the polymer refers to the "stem" portion of the chain containing the longest atoms in the polymer. Furthermore, the "stem" portion may contain ring structures. That is, "having a specific nitrogen-containing structure in the main chain" means that the structure constitutes part of the main chain. The term "side chain" refers to a portion that branches off from the "stem" of the polymer.

[0085] There are no particular limitations on the method for obtaining a polymer containing structural unit (B). In terms of the ease with which the polymer [P] can be manufactured, it is preferable to use a monomer (hereinafter also referred to as "third monomer") having at least one of the group consisting of a nitrogen-containing heterocycle and a partial structure represented by the formula (2).

[0086] When the structural unit (A) is derived from the structural unit of the first monomer, from the viewpoint of easily obtaining a polymer containing both structural unit (A) and structural unit (B) within one molecule, the third monomer is preferably a diamine compound. Specifically, it is preferably at least one selected from the group consisting of compounds represented by formula (3-1), compounds represented by formula (3-2), and compounds represented by formula (3-3).

[0087] [Chemistry 11]

[0088]

[0089] (In equation (3-1), B) 1 and B 3 Each can be independently a divalent aromatic hydrocarbon group, a divalent nitrogen-containing heterocyclic group, or a -Z group. 1 -OZ 2 -(where Z) 1 and Z 2 Each is an independent divalent aromatic hydrocarbon group. B 2 It is a single bond, a divalent hydrocarbon group, or has a carbon-carbon bond selected from -O- or -NR between the carbon-carbon bonds of the hydrocarbon group. 2 -and-CO-NR 2 -(where R) 2 It is a divalent group consisting of at least one of the group consisting of a hydrogen atom or a monovalent organic group. 1 and X 2 Each can be a divalent nitrogen-containing heterocyclic group or a divalent group represented by formula (2). L 1 and L 2 Each can be a single bond or a divalent linker, independently. m is an integer from 0 to 2.

[0090] In equation (3-2), B 4 It is a divalent organogroup. Y 1 It is a monovalent group having at least one of the group consisting of a nitrogen-containing heterocycle and a partial structure represented by the formula (2).

[0091] In equation (3-3), B 5 It is a divalent nitrogen-containing aromatic ring group.

[0092] In the above equation (3-1), B is... 1 and B 3 Aromatic hydrocarbon groups can be categorized as those formed by removing two hydrogen atoms from aromatic hydrocarbon rings such as benzene, naphthalene, and anthracene. B 1 and B 3The aromatic hydrocarbon group in the ring may have substituents. Examples of such substituents include: alkyl groups such as methyl and ethyl; alkoxy groups such as methoxy and ethoxy; and halogen atoms. 1 and B 3 The nitrogen-containing heterocyclic group is preferably a group formed by removing two hydrogen atoms from an aromatic heterocycle. The aromatic heterocycle is preferably a pyridine ring, pyrimidine ring, pyrazine ring, or benzimidazole ring.

[0093] In B 2 In this context, as a divalent hydrocarbon group, examples include chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. As an R... 2 Monovalent organic groups can be listed as monovalent hydrocarbon groups with 1 to 10 carbon atoms, as well as deionized groups.

[0094] When X 1 X 2 When it is a divalent nitrogen-containing heterocyclic group, the nitrogen-containing heterocyclic group can be exemplified by removing two hydrogen atoms from a nitrogen-containing heterocyclic ring exemplified as the nitrogen-containing heterocyclic structure possessed by structural unit (B). When X 1 X 2 When it is a divalent nitrogen-containing heterocyclic group, X 1 X 2 Preferably, it is a group formed by removing two hydrogen atoms from a heterocycle that has a substituent (methyl, ethyl, etc.) introduced into the pyridine ring, pyrimidine ring, pyrazine ring, piperidine ring, piperazine ring, quinoline ring, benzimidazole ring, or carbazole ring, or a heterocycle into which a substituent (methyl, ethyl, etc.) has been introduced.

[0095] m is preferably 0 or 1.

[0096] L 1 L 2 Preferably, it is a single bond or an alkyl diene, more preferably a single bond.

[0097] In formula (3-2), the divalent organic group is preferably a group having an aromatic ring, more preferably a group in formula (3-2) where two primary amino groups are bonded to the same or different aromatic rings. The aromatic ring is preferably an aromatic hydrocarbon ring, more preferably a benzene ring.

[0098] When Y 1 When the nitrogen-containing heterocycle is a monovalent group having a nitrogen-containing heterocycle, examples of nitrogen-containing heterocycles exemplified as nitrogen-containing heterocycle structures possessed by structural unit (B) can be given. When Y 1 When it is a monovalent group having a nitrogen-containing heterocycle, where Y 1 Preferably, it is a heterocycle having a pyridine ring, pyrimidine ring, pyrazine ring, piperidine ring, piperazine ring, benzimidazole ring, or quinoline ring, or having a substituent (methyl, ethyl, etc.) introduced into these rings. These heterocycles can be related to B in formula (3-2). 4Direct bonding is possible, or bonding can be achieved via an n-valent linker (where n is an integer of 2 or more). Examples of n-valent linkers include: -O-, -NR-, -CO-NR-, n-valent chain hydrocarbon groups with 1 to 5 carbon atoms, and divalent groups formed by replacing any methylene group of the chain hydrocarbon group with -O-, -COO-, -NR-, or -CO-NR- (where R is a hydrogen atom or a monovalent organic group).

[0099] In the above equation (3-3), B is... 5 Examples of nitrogen-containing aromatic rings include: pyridine ring, pyrimidine ring, pyrazine ring, quinoline ring, carbazole ring, benzimidazole ring, etc.

[0100] When the third monomer is a diamine compound, specific examples of the third monomer include: 4,4'-diaminodiphenylamine, N-methyl-4,4'-diaminodiphenylamine, N-ethyl-4,4'-diaminodiphenylamine, N-phenyl-4,4'-diaminodiphenylamine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, and compounds represented by formulas (5-1) to (5-22) below.

[0101] [Chemistry 12]

[0102]

[0103] [Chemistry 13]

[0104]

[0105] [Chemistry 14]

[0106]

[0107] (In equations (5-1) to (5-22), t is an integer from 1 to 12. n is an integer from 1 to 5. t-Boc represents tert-butoxycarbonyl.)

[0108] When structural unit (A) is derived from the structural unit of the second monomer, from the viewpoint of easily obtaining a polymer containing both structural unit (A) and structural unit (B) within a single molecule, the third monomer is preferably a compound containing a polymerizable unsaturated bond. The compound containing the polymerizable unsaturated bond as the third monomer is not particularly limited as long as it has a specific nitrogen-containing structure and a polymerizable unsaturated bond group. Examples of polymerizable unsaturated bond groups that can be found in the third monomer include: (meth)acryloyl, maleimide, and vinyl groups (including vinyl groups contained in alkenyl, vinylphenyl, and vinyl ether groups).

[0109] When the third monomer is a compound containing a polymerizable unsaturated bond, specific examples of the third monomer include: 2-(dimethylamino)ethyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, 3-(dimethylamino)propyl (meth)acrylate, N-(4-dimethylaminophenyl)maleimide, N-(4-diethylaminophenyl)maleimide, 4-(dimethylamino)styrene, 4-(diethylamino)styrene, and the following formulas (N-1) to (N-9).

[0110] [Chemistry 15]

[0111]

[0112] The compounds represented respectively. In addition, R in formula (N-3) is a hydrogen atom or a methyl group.

[0113] In polymer [P], from the viewpoint of sufficiently improving solubility and sufficiently reducing the accumulation of residual charge, the content of structural unit (B) is preferably 0.25 mol% or more relative to the total amount of monomer-derived structural units in polymer [P]. The content of structural unit (B) is more preferably 0.5 mol% or more, and even more preferably 2.5 mol% or more, relative to the total amount of monomer-derived structural units in polymer [P]. Furthermore, when structural unit (A) is a structural unit derived from the first monomer, from the viewpoint of making the ratio of structural unit (A) to structural unit (B) in polymer [P] within a preferred range and more efficiently reducing the accumulation of residual charge, the content of structural unit (B) is preferably 45 mol% or less, more preferably 35 mol% or less, even more preferably 30 mol% or less, and even more preferably 25 mol% or less, relative to the total amount of monomer-derived structural units in polymer [P]. When the structural unit (A) is a structural unit derived from the second monomer, the content of structural unit (B) is preferably 50 mol% or less, more preferably 45 mol% or less, and even more preferably 40 mol% or less, relative to the total amount of structural units derived from the monomer in the polymer [P]. Furthermore, the polymer [P] may contain only one type of structural unit (B), or it may contain two or more types.

[0114] Regarding the ratio of structural units (A) and (B) in the polymer [P], from the viewpoint of fully obtaining the solubility of the polymer and the effect of reducing the accumulation of residual charge, the ratio of structural unit (A) to structural unit (B) is preferably 5 mol% to 40 mol% and the ratio of structural unit (B) is 0.25 mol% to 45 mol% relative to the total amount of structural units derived from the monomer in the polymer [P]. From this viewpoint, the ratio of structural units (A) to structural units (B) is more preferably 10 mol% to 40 mol% and the ratio of structural unit (B) is 0.5 mol% to 30 mol%, further preferably 10 mol% to 30 mol% and the ratio of structural unit (B) is 2.5 mol% to 30 mol%, and even more preferably 15 mol% to 25 mol% and the ratio of structural unit (B) is 2.5 mol% to 15 mol%.

[0115] Regarding the ratio of structural units (A) to structural units (B) in the polymer [P], from the viewpoint of fully obtaining the solubility of the polymer and the effect of reducing the accumulation of residual charge, a ratio of structural unit (A):structural unit (B) of 1:0.01 to 3 (molar ratio) is preferred. The ratio (molar ratio) of structural units (A) to structural units (B) in the polymer [P] is more preferably 1:0.025 to 3, further preferably 1:0.125 to 3, and even more preferably 1:0.15 to 3. When the first monomer is a diamine compound, the total amount of structural units (A) and structural units (B) in the polymer [P] is preferably 50 mol% or less relative to the total amount of structural units derived from the monomer. Furthermore, when the first monomer is a compound containing polymerizable unsaturated bonds, the total amount of structural units derived from the monomer in the polymer [P] is preferably 60 mol% or less, more preferably 50 mol% or less.

[0116] • Regarding polymers [P]

[0117] The main chain of polymer [P] is not particularly limited. However, in terms of forming a liquid crystal alignment film with high affinity for liquid crystal and high mechanical strength and reliability, and in terms of high freedom of monomer selection, polymer [P] is preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester, polyimide and addition polymers.

[0118] (Polyamic acid)

[0119] When the polymer [P] is polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid [P]") is preferably manufactured by reacting a tetracarboxylic dianhydride with a diamine compound containing a first monomer and a third monomer.

[0120] (Tetracarboxylic acid dianhydride)

[0121] Examples of tetracarboxylic dianhydrides used in the synthesis of polyamic acid [P] include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides. Specific examples of aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic acid dianhydride; examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, and 5-(2,5-dioxotetrahydrofuran-3-yl)-8- Methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic bicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, etc.; aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)phthalic anhydride, ethylene glycol bis(triphenylene)phthalic anhydride, 4,4'-carbonyl phthalic anhydride, etc., and other tetracarboxylic dianhydrides described in Japanese Patent Application Publication No. 2010-97188 may also be used. One tetracarboxylic dianhydride may be used alone or in combination of two or more.

[0122] In terms of obtaining liquid crystal alignment films with high solubility relative to solvents, exhibiting good electrical properties and low image retention, the tetracarboxylic dianhydride used in the synthesis of polyamic acid [P] is preferably at least one compound selected from the group consisting of aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, more preferably alicyclic tetracarboxylic dianhydrides. The proportion of alicyclic tetracarboxylic dianhydrides used relative to the total amount of tetracarboxylic dianhydrides used in the synthesis of polyamic acid [P] is preferably 20 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more.

[0123] (Diamine compounds)

[0124] The diamine compound used in the synthesis of polyamic acid [P] can be only the first monomer and the third monomer, or it can be combined with a diamine different from the first monomer and the third monomer (hereinafter also referred to as "other diamines"). Examples of other diamines include: aliphatic diamines, alicyclic diamines, aromatic diamines, diamino organosiloxanes, etc.

[0125] Specific examples of other diamines include aliphatic diamines such as m-xylenediamine and hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); and aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4-aminophenyl-4-aminobenzoic acid ester, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, and 1,6-bis( Main-chain diamines include 4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]adipic acid, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylene diisopropylidene)bisaniline, 1-amino-3-aminomethylbenzene, and 4,4'-bis(4-aminophenoxy)biphenyl.

[0126] Hexadecyloxy-2,4-diaminobenzene, Octadecyloxy-2,4-diaminobenzene, Octadecyloxy-2,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholesteryl 3,5-diaminobenzoate, Cholesterol 3,5-diaminobenzoate, 3,5-diaminobenzene Lanostane benzoate, 3,6-bis(4-aminobenzoyloxy)cholestan, 3,6-bis(4-aminophenoxy)cholestan, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, and the following formula (E-1)

[0127] [Chemistry 16]

[0128]

[0129] (In formula (E-1), X) I and X II Each can be used independently to represent a single bond, -O-, *-COO-, or *-OCO- (where "*" indicates a bond with X). I The bond structure. ). R I It is an alkyldiyl group having 1 to 3 carbon atoms. R II It is a single bond or an alkyldiyl group having 1 to 3 carbon atoms. R IIIIt can be an alkyl, alkoxy, fluoroalkyl, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer from 0 to 3. c is an integer from 0 to 2. d is 0 or 1. Where 1 ≤ a + b + c ≤ 3.

[0130] The compounds represented include side-chain diamines such as diamines with cinnamate ester structures in their side chains.

[0131] Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. Examples of compounds represented by formula (E-1) include those represented by formulas (E-1-1) to (E-1-4).

[0132] [Chemistry 17]

[0133]

[0134] When synthesizing polyamic acid [P], the proportion of other diamines used relative to the total amount of diamine compounds used in the synthesis of polyamic acid [P] is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. As other diamines, one or more may be used alone or in combination.

[0135] (Synthesis of polyamic acid)

[0136] Polyamic acid [P] can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, and optionally with a molecular weight adjuster. In the synthesis reaction of polyamic acid [P], the preferred ratio of tetracarboxylic dianhydride to diamine compound is 0.2 to 2 equivalents relative to the amino group of the diamine compound. Examples of molecular weight adjusters include: maleic anhydride, phthalic anhydride, itaconic anhydride, etc.; monoamine compounds such as aniline, cyclohexylamine, n-butylamine, etc.; and monoisocyanate compounds such as phenyl isocyanate, naphthyl isocyanate, etc. The ratio of the molecular weight adjuster to the total 100 parts by mass of the tetracarboxylic dianhydride and diamine compound used is preferably 20 parts by mass or less.

[0137] The synthesis reaction of polyamic acid [P] is preferably carried out in an organic solvent. The preferred reaction temperature is -20°C to 150°C, and the preferred reaction time is 0.1 hours to 24 hours. Examples of organic solvents used in the reaction include: aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Specific examples preferably include one or more solvents selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamine, m-cresol, xylenol, and halogenated phenols, or a mixture of these solvents with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of organic solvent used (a) is preferably set to be 0.1% to 50% by mass relative to the total amount of the reaction solution (a+b) of the combined amount of tetracarboxylic acid dianhydride and diamine.

[0138] A polymer solution containing dissolved polyamic acid [P] is obtained in the manner described above. The polymer solution can be used directly for the preparation of a liquid crystal alignment agent, or it can be used for the preparation of a liquid crystal alignment agent after the polyamic acid [P] contained in the polymer solution has been separated.

[0139] <Polyamic acid ester>

[0140] When polymer [P] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [P]") can be obtained, for example, by the following methods: [I] reacting polyamic acid [P] with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. Polyamic acid ester [P] may have only an amide ester structure, or it may be a partial esterification with both an amide acid structure and an amide ester structure. The reaction solution obtained by dissolving polyamic acid ester [P] can be directly used in the preparation of a liquid crystal alignment agent, or it can be used in the preparation of a liquid crystal alignment agent after separating the polyamic acid ester [P] contained in the reaction solution.

[0141] <Polyimide>

[0142] When the polymer [P] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [P]") can be obtained, for example, by dehydrating and ring-closing a polyamic acid [P] synthesized in the manner described above, and then imidizing it. The polyimide [P] can be a fully imidized product obtained by dehydrating and ring-closing all the amic acid structures possessed by the polyamic acid [P] as its precursor, or it can be a partially imidized product obtained by dehydrating and ring-closing only a portion of the amic acid structure, resulting in the coexistence of the amic acid structure and the imide ring structure. The polyimide [P] preferably has an imidization rate of 20% to 99%, more preferably 30% to 90%. Furthermore, the imidization rate is expressed as a percentage representing the proportion of the number of imide ring structures relative 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.

[0143] The dehydration and ring-closure of polyamic acid [P] is preferably carried out by dissolving polyamic acid [P] in an organic solvent, adding a dehydrating agent and a dehydration and ring-closure catalyst to the solution, and heating as needed. In this method, anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as dehydrating agents. The amount of dehydrating agent used is preferably 0.01 mol to 20 mol relative to 1 mol of the amic acid structure of polyamic acid [P]. Tertiary amines such as pyridine, trimethylpyridine, dimethylpyridine, and triethylamine can be used as dehydration and ring-closure catalysts. The amount of dehydration and ring-closure catalyst used is preferably 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. Examples of organic solvents used in the dehydration and ring-closure reaction include those used in the synthesis of polyamic acid [P]. The reaction temperature for the dehydration and ring-closure reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 h to 120 h. Furthermore, the reaction solution containing polyimide [P] can be used directly for the preparation of liquid crystal alignment agents, or it can be used for the preparation of liquid crystal alignment agents after the polyimide [P] is separated.

[0144] Regarding the solution viscosity of polymer [P], when preparing a 10% by mass solution, a solution viscosity of 10 mPa·s to 800 mPa·s is preferred, and a solution viscosity of 15 mPa·s to 500 mPa·s is more preferred. Furthermore, the solution viscosity (mPa·s) is a value obtained by measuring a 10% by mass polymer solution prepared using a type E rotational viscometer at 25°C with a good solvent for polymer [P] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0145] The weight-average molecular weight (Mw) of the polymer [P], as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 7 or less, more preferably 5 or less.

[0146] (Addition polymer)

[0147] When the polymer [P] is an addition polymer, the addition polymer (hereinafter also referred to as "addition polymer [P]") can be obtained by polymerizing a compound containing polymerizable unsaturated bonds comprising a second monomer and a third monomer. In terms of forming a liquid crystal alignment film with excellent liquid crystal alignment properties, the addition polymer [P] is preferably at least one selected from the group consisting of poly(meth)acrylates and maleimide polymers (including styrene-maleimide copolymers).

[0148] When synthesizing addition polymers [P], monomers other than the second and third monomers (hereinafter also referred to as "other compounds containing polymerizable unsaturated bonds") may be used. Examples of other compounds containing polymerizable unsaturated bonds include: (meth)acrylic acid compounds, styrene compounds, conjugated diene compounds, maleimide compounds, etc.

[0149] As specific examples of other compounds containing polymerizable unsaturated bonds, (meth)acrylic acid compounds include, for example, unsaturated carboxylic acid esters such as alkyl (meth)acrylates (e.g., methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cycloalkyl (meth)acrylate, benzyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 3,4-epoxycyclohexyl methyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 4-hydroxybutyl glycidyl (meth)acrylate.

[0150] Examples of styrene compounds include: styrene, methylstyrene, divinylbenzene, and 4-(glycidoxymethyl)styrene. Examples of conjugated diene compounds include: 1,3-butadiene and 2-methyl-1,3-butadiene. Examples of maleimide compounds include: N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(4-glycidoxyphenyl)maleimide, and N-glycidylmaleimide. In the synthesis of addition polymers [P], one or more unsaturated monomers can be used alone or in combination as other unsaturated monomers.

[0151] Addition polymers [P] can be obtained, for example, by polymerizing monomers in the presence of a polymerization initiator. Preferred polymerization initiators include, for example, azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), and 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile). The proportion of the polymerization initiator used is preferably set to 0.01 to 30 parts by mass relative to 100 parts by mass of all monomers used in the reaction.

[0152] The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds, with diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate being preferred. The reaction temperature is preferably set to 30°C to 120°C, and the reaction time is preferably set to 1 hour to 36 hours. The amount (a) of organic solvent used is preferably set to be 0.1% to 60% by mass relative to the total amount (b) of the monomers used in the reaction and the total amount (a+b) of the reaction solution.

[0153] For the addition polymer [P], the weight-average molecular weight (Mw) of polystyrene as determined by GPC is preferably 250 to 500,000, more preferably 500 to 100,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene as determined by GPC, is preferably 8 or less, more preferably 6 or less.

[0154] Relative to the total amount of solid components contained in the liquid crystal alignment agent (i.e., the total mass of the components of the liquid crystal alignment agent excluding the solvent), the content of polymer [P] in the liquid crystal alignment agent is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. Furthermore, when preparing the liquid crystal alignment agent, polymer [P] can be used alone or in combination of two or more types.

[0155] <Other Ingredients>

[0156] In addition to polymer [P], liquid crystal alignment agents may also contain components different from polymer [P] (hereinafter referred to as "other components") as needed.

[0157] (Other polymers)

[0158] The liquid crystal alignment agent disclosed herein may also contain a polymer (hereinafter also referred to as "other polymer (1)") that does not have at least one of structural unit (A) and structural unit (B) as a polymer component. The main framework of the other polymer (1) is not particularly limited. Examples of other polymers (1) include: polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamide-imide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic acid polymer, styrene polymer, maleimide polymer, or styrene-maleimide copolymer. Among these, in terms of high affinity with liquid crystal when used with polymer [P] and improved reliability of liquid crystal element, the other polymer (1) is preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and polymers containing structural units derived from monomers having carbon-carbon unsaturated bonds. The polymer comprising structural units derived from monomers having carbon-carbon unsaturated bonds is preferably selected from at least one group consisting of (meth)acrylic polymers, styrene polymers, maleimide polymers, and styrene-maleimide copolymers.

[0159] When the liquid crystal alignment agent contains other polymers (1), the content of other polymers (1) 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 polymer [P] and other polymers (1). As other polymers, one can be used alone or two or more can be used in combination.

[0160] (solvent)

[0161] The liquid crystal alignment agent disclosed herein is prepared in the form of a liquid composition of polymer [P] and other components used as needed, preferably dispersed or dissolved in a suitable solvent.

[0162] Organic solvents are preferred. Specific examples include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolone, 1,3-dimethyl-2-imidazolone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, and acetoacetic acid. Methyl ester, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisoamyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentane, cyclohexane, etc. They can be used alone or in combination.

[0163] Other components included in the liquid crystal alignment agent, besides those mentioned above, include, for example, crosslinking agents, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, and photosensitizers. The proportions of these other components can be appropriately selected based on the specific compound without compromising the effectiveness of the invention.

[0164] The concentration of solid components in the liquid crystal alignment agent (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) is appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1% to 10% by mass. If the solid component concentration is 1% by mass or more, the film thickness of the coating can be sufficiently ensured, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be easily obtained. On the other hand, if the solid component concentration is 10% by mass or less, the coating thickness can be appropriately achieved, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be easily obtained. In addition, the viscosity of the liquid crystal alignment agent becomes moderate, which tends to improve coatability.

[0165] [Second Implementation]

[0166] The liquid crystal alignment agent of the second embodiment contains a polymer [P1] comprising structural unit (A) and a polymer [P2] comprising structural unit (B). Regarding structural unit (A) and structural unit (B), the same applies as in the first embodiment, and the description of the first embodiment can be referenced.

[0167] Furthermore, polymer [P1] is a polymer that substantially does not have structural units (B), and polymer [P2] is a polymer that substantially does not have structural units (A). Here, in this specification, "substantially does not have" a specific structural unit means less than 0.5 mol% relative to the total amount of structural units derived from monomers in the polymer, and preferably less than 0.2 mol%, more preferably less than 0.1 mol%.

[0168] In liquid crystal alignment agents comprising polymers [P1] and [P2], the main chains of polymers [P1] and [P2] are not particularly limited. From the viewpoint of affinity with liquid crystals, mechanical strength, and reliability, polymers [P1] and [P2] are preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymers. Specifically, the following forms are listed as preferred examples.

[0169] <1> Polymers [P1] and [P2] are in the form of at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

[0170] <2> One of polymers [P1] and polymer [P2] is selected from at least one of the group consisting of polyamic acid, polyamic acid ester and polyimide, and the other is in the form of an addition polymer.

[0171] In polymers [P1] and [P2], the polymer that is a polyamic acid, polyamic ester, or polyimide is preferably a polymer having structural units derived from alicyclic tetracarboxylic dianhydrides. Examples and preferred proportions of alicyclic tetracarboxylic dianhydrides can be found in the description of the first embodiment.

[0172] In the liquid crystal alignment agent of the second embodiment, from the viewpoint of fully obtaining the solubility of the polymer and the effect of reducing the accumulation of residual charge, the ratio of polymer [P1] to polymer [P2] is preferably such that the ratio (molar ratio) of structural unit (A) to structural unit (B) in the liquid crystal alignment agent is structural unit (A): structural unit (B) = 1:0.01 to 3. The ratio (molar ratio) of structural unit (A) to structural unit (B) in the liquid crystal alignment agent is more preferably 1:0.025 to 3, more preferably 1:0.125 to 3, and more preferably 1:0.15 to 3.

[0173] In addition to polymers [P1] and [P2], the liquid crystal alignment agent of the second embodiment may also contain components different from polymers [P1] and [P2], depending on the need. Examples of such components include polymers that do not have either structural unit (A) or structural unit (B) (hereinafter also referred to as "other polymers (2)"), solvents, etc. Regarding the main framework of the other polymers (2), examples include the same main framework as the polymer exemplified as other polymers (1) in the first embodiment. Details regarding solvents, etc., are the same as in the first embodiment, and the above description is applicable.

[0174] Liquid crystal alignment films and liquid crystal elements

[0175] The liquid crystal alignment film of this disclosure can be manufactured using a liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of this disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA) (including vertical alignment-multi-domain vertical alignment (VA-MVA), vertical alignment-patterned vertical alignment (VA-PVA), etc.), in-plane switching (IPS), fringe field switching (FFS), optically compensated bend (OCB), and polymer-sustained alignment (PSA). Liquid crystal elements can be manufactured, for example, using a method comprising steps 1 to 3 below. Step 1 uses different substrates depending on the required operating mode. Steps 2 and 3 are common to all operating modes.

[0176] <Step 1: Coating Formation>

[0177] First, a liquid crystal alignment agent is coated onto a substrate, preferably by heating the coated surface to form a coating film on the substrate. Examples of substrates that can be used include: float glass, soda glass, etc.; and transparent substrates containing plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefins). As the transparent conductive film disposed on the substrate, NESA film (a registered trademark of PPG Industries, Inc.) containing tin oxide (SnO2) or indium tin oxide (ITO) film containing indium oxide-tin oxide (In2O3-SnO2) can be used. In the case of manufacturing TN, STN, or VA type liquid crystal elements, two substrates with patterned transparent conductive films are used. On the other hand, in the case of manufacturing IPS or FFS type liquid crystal elements, a substrate with electrodes patterned in a comb-like shape and an opposing substrate without electrodes are used.

[0178] There are no particular limitations on the method of applying liquid crystal alignment agent to the substrate. For example, it can be done by spin coating, printing (e.g., offset printing, flexographic printing), inkjet printing, slot coating, bar coating, extrusion die coating, direct gravure coating, chamber doctor coating, offset gravure coating, impregnation coating, MB coating, etc.

[0179] After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed to prevent sagging of the coated liquid crystal alignment agent. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Subsequently, the solvent is further removed, and a calcination (post-baking) process is performed as needed to thermally imidize the amyl acid structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The thickness of the formed film is preferably 0.001 μm to 1 μm.

[0180] <Step 2: Orientation Treatment>

[0181] In the manufacture of TN, STN, IPS, or FFS type liquid crystal elements, the coating film formed in step 1 is subjected to a process (alignment treatment) to impart liquid crystal alignment capability. This imparts the alignment capability of liquid crystal molecules to the coating film, forming a liquid crystal alignment film. Preferably, the alignment treatment involves rubbing the surface of the coating film formed on the substrate with cotton or the like, or photoalignment treatment by irradiating the coating film with light to impart liquid crystal alignment capability. In the manufacture of vertically aligned liquid crystal elements, the coating film formed in step 1 can be used directly as a liquid crystal alignment film; however, to further improve the liquid crystal alignment capability, an alignment treatment can also be performed on the coating film.

[0182] Light irradiation for photoorientation can be performed by methods such as: irradiating a coating after a post-baking process; irradiating a coating after a pre-baking process and before a post-baking process; or irradiating a coating during heating in at least one of the pre-baking and post-baking processes. As the radiation irradiating the coating, ultraviolet light and visible light with wavelengths from 150 nm to 800 nm can be used, for example. Ultraviolet light with wavelengths from 200 nm to 400 nm is preferred. When the radiation is polarized, it can be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these directions. For unpolarized radiation, the irradiation direction is set to an oblique direction.

[0183] Examples of light sources used include: low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The preferred radiation dose is 200 J / m². 2 ~30,000J / m 2 More preferably 500 J / m 2 ~10,000J / m 2 After light irradiation to impart orientation capability, the substrate surface may also be cleaned using, for example, water, organic solvents (e.g., methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or mixtures thereof, or the substrate may be heated.

[0184] <Step 3: Construction of the Liquid Crystal Cell>

[0185] Two substrates with liquid crystal alignment films formed as described above are prepared, and liquid crystal is disposed between the two substrates arranged facing each other, thereby manufacturing a liquid crystal cell. In manufacturing the liquid crystal cell, methods such as: arranging two substrates facing each other with the liquid crystal alignment films facing each other and a gap between them; bonding the peripheries of the two substrates together using a sealant; injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant and sealing the injection hole; or using a one-drop fill (ODF) method. As a sealant, for example, epoxy resin containing a hardener and alumina spheres as spacers can be used. As a liquid crystal, nematic liquid crystals and dish liquid crystals can be used, with nematic liquid crystals being preferred.

[0186] In PSA mode, the following process is performed: a polymeric compound (e.g., a polyfunctional (meth)acrylate compound, etc.) is filled into the cell gaps along with liquid crystal, and after the liquid crystal cells are constructed, the liquid crystal cells are irradiated with light while a voltage is applied between the conductive films of a pair of substrates. When manufacturing PSA-type liquid crystal elements, the proportion of the polymeric compound used relative to 100 parts by mass of the total liquid crystal is, for example, 0.01 to 3 parts by mass, preferably 0.05 to 1 part by mass.

[0187] In the manufacture of a liquid crystal display device, a polarizing plate is then attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. Examples of polarizing plates include polarizing plates made by sandwiching a polarizing film called an "H-film" with a cellulose acetate protective film, or polarizing plates containing an H-film itself, wherein the "H-film" is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0188] Furthermore, the reason why a liquid crystal alignment agent containing a polymer [P] can achieve good coatability and reduce the accumulation of residual charge is still uncertain, but it is believed to be as follows. Based on a polymer containing structural units having carboxyl groups and structural units having basic groups, it is believed that charge transfer in the liquid crystal alignment film can be efficiently carried out through the acid-base interaction between the carboxyl groups and basic groups, thereby reducing the charge accumulated in the liquid crystal element. On the other hand, in a liquid crystal alignment agent containing a polymer containing structural units having carboxyl groups and structural units having basic groups, it is believed that the polymer tends to aggregate due to the acid-base interaction between the carboxyl groups and basic groups, resulting in reduced coatability. In contrast, the liquid crystal alignment agent of the first embodiment contains a polymer [P], which has a structural unit (A) as a structural unit having carboxyl groups and a structural unit (B) as a structural unit having basic groups. According to the liquid crystal alignment agent of the first embodiment, it is believed that by utilizing the appropriately sized groups (A... 1 To protect the carboxyl group, steric hindrance can be created; additionally, it can reduce the number of groups A that detach.1 The amount remaining in the film thus helps the coatability of the liquid crystal alignment agent and reduces the accumulation of residual charge.

[0189] Furthermore, it is believed that the same applies when a blending system is formed, consisting of a polymer [P1] having structural unit (A) and a polymer [P2] having structural unit (B). That is, in polymers containing structural units with carboxyl groups and polymers containing structural units with basic groups, it is believed that the polymer components tend to aggregate due to the acid-base interaction between the carboxyl and basic groups. In contrast, according to the liquid crystal alignment agent of the second embodiment containing polymers [P1] and [P2], it is believed that by utilizing groups (A) of appropriate size… 1 To protect the carboxyl group, steric hindrance can be created; additionally, it can reduce the number of groups A that detach. 1 The amount of residue in the film thus improves coatability while reducing the accumulation of residual charge.

[0190] The liquid crystal element of this invention can be effectively applied to a variety of uses. Specifically, it can be used in various display devices or dimming devices, such as clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, etc., as well as retardation films.

[0191] [Example]

[0192] The following describes the implementation methods in more detail based on the embodiments, but the invention is not to be construed as limited by the following embodiments. Furthermore, unless otherwise specified, "parts" and "%" in the embodiments and comparative examples are quality standards.

[0193] In the following examples, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer, the imidization rate of the polyimide in the polymer solution, and the solution viscosity of the polymer solution were determined by the following methods. The required amounts of the starting materials and polymers used in the following examples were ensured by repeating the synthesis at the scale shown in the following synthesis examples as needed.

[0194] [Weight-average molecular weight Mw and quantity-average molecular weight Mn]

[0195] The weight-average molecular weight Mw and the number-average molecular weight Mn are polystyrene conversion values ​​determined by GPC under the following conditions.

[0196] Tube column: Manufactured by Tosoh (stock), TSKgelGRCXLII

[0197] Solvent: Tetrahydrofuran

[0198] Temperature: 40℃

[0199] Pressure: 68 kgf / cm 2

[0200] [Imidification rate of polyimide]

[0201] A solution of polyimide was added to pure water, and the resulting precipitate was dried under reduced pressure at room temperature. It was then dissolved in dimethyl sulfoxide (DMSO), and tetramethylsilane was used as a reference. The 1H NMR spectrum was measured at room temperature. 1 H-nuclear magnetic resonance, 1 H-NMR). Based on the obtained 1 The imidization rate [%) was determined using the following formula (1) from the H-NMR spectrum.

[0202] Imidification rate [%] = (1-(A) 1 / (A 2 ×α)))×100…(1)

[0203] (In equation (1), A 1 It is the peak area of ​​protons originating from NH groups that appears near a chemical shift of 10 ppm, A 2 It is the peak area derived from other protons, and α is the ratio of the number of other protons to the number of 1 proton of the NH group in the polymer precursor (polyamic acid).

[0204] [Solution viscosity of polymer solution]

[0205] The solution viscosity of the polymer was measured using an E-type viscometer at 25°C.

[0206] The compounds used in the following examples and comparative examples are referred to by the following abbreviations. Furthermore, hereinafter, compounds represented by formula (X) are sometimes simply referred to as "compound (X)".

[0207] [Chemistry 18]

[0208]

[0209] [Chemistry 19]

[0210]

[0211] [Chemistry 20]

[0212]

[0213] [Chemistry 21]

[0214]

[0215] [Chemistry 22]

[0216]

[0217] [Chemistry 23]

[0218]

[0219] [Chemistry 24]

[0220]

[0221] <Synthesis of Polymers>

[0222] 1. Synthesis of polyamic acid

[0223] [Synthesis example 1]

[0224] 20 moles of cyclobutane-1,2:3,4-tetracarboxylic dianhydride, 50 moles of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, and 30 moles of pyromellitic dianhydride, along with 5 moles of compound (d-1) as a diamine, 45 moles of 4,4'-diaminodiphenylmethane, 20 moles of cholesteroloxy-2,4-diaminobenzene, and 30 moles of compound (d-14), were dissolved in N-methyl-2-pyrrolidone (NMP). The reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (designated as polymer (PA-1)). A small amount of the solution was aliquoted, and NMP was added to prepare a 10% by mass solution, which was then measured. The viscosity of the solution was 100 mPa·s.

[0225] [Synthesis Example 2 to Synthesis Example 16]

[0226] The types and amounts of tetracarboxylic dianhydride and diamine compounds used were changed as described in Table 1 below. Otherwise, the same operation as in Synthesis Example 1 was performed to obtain polyamic acid (polymer (PA-2) to polymer (PA-16)).

[0227] 2. Synthesis of polyimide

[0228] [Synthesis Example 17]

[0229] 100 moles of 2,3,5-tricarboxycyclopentylacetic acid dianhydride (as a tetracarboxylic acid dianhydride), 30 moles of compound (d-2) (as a diamine compound), 30 moles of cholesterololoxy-2,4-diaminobenzene, and 40 moles of compound (d-15) were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid.

[0230] Subsequently, NMP was added to the obtained polyamic acid solution to prepare a 10% by mass solution of polyamic acid. Pyridine and acetic anhydride were then added, and a dehydration and ring-closure reaction was carried out at 60°C for 4 hours. After the dehydration and ring-closure reaction, the solvent in the system was replaced with fresh NMP, thereby obtaining a solution containing 10% by mass of polyimide with an imidization rate of 80% (designated as polymer (PI-1)). The viscosity of the obtained polymer solution was 100 mPa·s.

[0231] [Synthesis Example 18]

[0232] The types and amounts of the tetracarboxylic dianhydride and diamine compounds used were changed as described in Table 1, and the same procedures as in Synthesis Example 17 were performed to obtain a polyimide (designated as polymer (PI-2)). The imidization rate of the obtained polymer (PI-2) was 50%.

[0233] [Table 1]

[0234]

[0235] 3. Synthesis of Polyorganosiloxanes

[0236] [Synthesis Example 19]

[0237] 90.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were placed in a 1000 ml three-necked flask and mixed at room temperature. Then, 100 g of deionized water was added dropwise through a dropping funnel over 30 minutes, and the mixture was stirred under reflux at 80 °C for 6 hours. After the reaction was complete, the organic layer was removed and washed with a 0.2% ammonium nitrate aqueous solution until the washing water was neutral. The solvent and water were then removed by distillation under reduced pressure. A suitable amount of methyl isobutyl ketone was added to obtain a 50% solution of an epoxy-containing polyorganosiloxane polymer (ESSQ-1).

[0238] In a 500 ml three-necked flask, 6.28 g of compound (CA-1) (20 mol% epoxy group content relative to polymer (ESSQ-1), 3.44 g of compound (CA-2) (10 mol% epoxy group content relative to polymer (ESSQ-1), 2.00 g of tetrabutylammonium bromide, 80 g of a solution containing polymer (ESSQ-1), and 239 g of methyl isobutyl ketone were added. The mixture was stirred at 90 °C for 18 hours. After cooling to room temperature, the mixture was subjected to 10 separate washing operations using distilled water. The organic layer was then recovered, and the solution was concentrated twice using a rotary evaporator and diluted with NMP. The NMP solution of polymer (PS-1) was then adjusted to a solids concentration of 10% by mass using NMP.

[0239] 4. Synthesis of addition polymers (styrene-maleimide polymers)

[0240] [Synthesis Example 20]

[0241] Under nitrogen atmosphere, 10 moles of compound (MA-1) and compound (MA-2) as monomers, 35 moles of methacrylic acid, and 45 moles of glycidyl methacrylate, 2 moles of 2,2'-azobis(2,4-dimethylpentanones) as a free radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent were added to a 100 mL two-necked flask. Polymerization was carried out at 70 °C for 5 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain the target polymer (PM-1). The weight-average molecular weight (Mw) determined by GPC and converted to polystyrene was 30,000, and the molecular weight distribution (Mw / Mn) was 2.

[0242] [Synthesis Example 21 to Synthesis Example 24]

[0243] The types and amounts of monomers used were changed as described in Table 2 below, and the same operation as in Synthesis Example 20 was performed to obtain addition polymers (polymers (PM-2) to (PM-5)).

[0244] [Table 2]

[0245]

[0246] 5. Preparation and evaluation of liquid crystal alignment agents

[0247] [Example 1: PSA type liquid crystal display element]

[0248] (1) Preparation of liquid crystal alignment agent (AL-1)

[0249] To a solution containing 100 parts by mass of the polymer (PA-1) obtained in Synthesis Example 1, a solution containing 10 parts by mass of the polymer (PS-1) obtained in Synthesis Example 19, 5 parts by mass of compound (Ad-1), and NMP and butyl cellosolve (BC) as solvents were added to prepare a solution with a solvent composition of NMP / BC = 50 / 50 (mass ratio) and a solid content concentration of 4.0% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0250] (2) Evaluation of solubility

[0251] The liquid crystal alignment agent (AL-1) prepared in (1) was stored in a freezer at -15°C for 7 days. After thawing to room temperature, the number of particles in the thawed liquid crystal alignment agent was measured to evaluate the solubility of the polymer. The particle count was determined using a liquid particle sensor (Rion KL-20A). The number of particles larger than 1.0 μm was measured twice in 10 ml of the liquid crystal alignment agent, and the average value was taken as the particle count. The measurement was performed under the following conditions: light source wavelength: 780 nm; sample aspiration rate: 10 ml / min.

[0252] In the evaluation, a particle count of 5 or less per ml was designated as "Good (○)", a count of 6 or more but less than 10 per ml was designated as "Acceptable (△)", and a count of 11 or more per ml was designated as "Poor (×)". In the above embodiment, the evaluation indicates good solubility.

[0253] (3) Preparation of liquid crystal compositions

[0254] To obtain liquid crystal composition LC1, 5% by mass of a liquid crystal compound represented by formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by formula (L2-1) were added to 10g of nematic liquid crystal (Merck, MLC-6608) and mixed.

[0255] [Chemistry 25]

[0256]

[0257] (4) Manufacturing of PSA type liquid crystal display elements

[0258] Using a liquid crystal alignment film printing machine (manufactured by Nippon Shashin Printing Co., Ltd.), the liquid crystal alignment agent (AL-1) prepared above was coated onto the electrode surfaces of two glass substrates, each having a conductive film containing ITO electrodes. The solvent was removed by heating (pre-baking) on ​​a hot plate at 80°C for 1 minute. Afterwards, the substrates were baked at 230°C for 30 minutes in a clean oven under nitrogen atmosphere to form a coating with an average film thickness of 0.1 μm, thus obtaining a pair (two) of substrates with liquid crystal alignment films. Furthermore, the electrode pattern used is the same as the electrode pattern in the PSA mode.

[0259] Next, on the outer edge of the surface of one of the two substrates with the liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 5.5 μm is applied. The substrates are then overlapped and pressed together with the liquid crystal alignment film surfaces facing each other, and the adhesive is allowed to harden. Then, the liquid crystal composition LC1 prepared above is filled between the two substrates through the liquid crystal injection port, and the liquid crystal injection port is sealed using an acrylic photocurable adhesive, thereby manufacturing a liquid crystal cell. Afterwards, under liquid crystal driving conditions with 60 Hz AC 10V applied between the conductive films of the liquid crystal cell, an ultraviolet irradiation device using a metal halide lamp as a light source is used at 100,000 J / m². 2 The substrate is irradiated with ultraviolet light at a specific irradiation level. This irradiation level is measured using a photometer with a wavelength of 365 nm as the reference. Then, polarizing plates are attached to the outer surfaces of the substrate with their polarization directions orthogonal to each other and at a 45° angle to the projection direction of the ultraviolet light axis of the liquid crystal alignment film onto the substrate surface, thereby manufacturing a PSA-type liquid crystal display element.

[0260] (5) Evaluation of residual DC / resistance

[0261] The liquid crystal display element manufactured in (4) was subjected to a 5V voltage at 60°C for 5 minutes, followed by a 1-second short circuit, and then kept open for 10 minutes. The charge accumulated in the liquid crystal display element during this period was measured by dielectric absorption method. In the evaluation, a voltage value of less than 0.20V was designated as "good (○)", a value greater than 0.21V and less than 0.50V was designated as "acceptable (△)", and a value greater than 0.51V was designated as "bad (×)". In the above embodiment, a low voltage value (i.e., less charge accumulated in the liquid crystal display element) was considered a good evaluation.

[0262] (6) Evaluation of coating properties (in-plane uniformity)

[0263] The liquid crystal alignment agent (AL-1) prepared in (1) was stored in a freezer at -15°C for 7 days. After thawing the liquid crystal alignment agent to room temperature, the coating properties (in-plane uniformity) were evaluated using the thawed liquid crystal alignment agent. The evaluation was performed using a JET-CM continuous inkjet printer (manufactured by Kishu Giken Kogyo Co., Ltd.). The thawed liquid crystal alignment agent was continuously coated onto an ITO substrate with a dry film thickness of 0.1 μm. The time required from the start of the liquid crystal alignment agent coating to the completion of the coating on the entire surface of the substrate and the subsequent calcination was 10 minutes. The obtained alignment film coated substrate was pre-baked on a hot plate at 80°C for 1 minute, and then baked in a clean oven at 230°C for 30 minutes under nitrogen atmosphere. The peripheral and central portions of the liquid crystal alignment film were then observed using a 20x microscope. At this point, the absence of pinholes and uneven coating (uneven film thickness) is judged as "good (○)", and the presence of at least one of pinholes and uneven coating is judged as "bad (×)".

[0264] [Examples 6-13, Comparative Examples 1-9]

[0265] The composition of the liquid crystal alignment agent was modified as shown in Table 3, except that the liquid crystal alignment agent was prepared with the same solvent composition and solid component concentration as in Example 1. Furthermore, using each liquid crystal alignment agent, the solubility and coatability were evaluated in the same manner as in Example 1, and PSA-type liquid crystal display elements were manufactured to evaluate the residual DC / resistance. The results are shown in Table 3. In Table 3, the values ​​in parentheses for each component in the alignment agent composition indicate the amount prepared (parts by mass).

[0266] [Example 2: Vertical-angle liquid crystal display element]

[0267] (1) Preparation of liquid crystal alignment agent and evaluation of its solubility and coatability

[0268] The composition of the liquid crystal alignment agent was modified as shown in Table 3. Except for this, the liquid crystal alignment agent (AL-2) was prepared with the same solvent composition and solid content concentration as in Example 1. Furthermore, the solubility and coatability of the liquid crystal alignment agent (AL-2) were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0269] (2) Manufacturing of vertical liquid crystal display elements

[0270] The liquid crystal alignment agent (AL-2) prepared above was coated onto the transparent electrode surface of a glass substrate with a transparent electrode containing an ITO film using a spinner, and pre-baked at 80°C for 1 minute. Then, the coating was heated at 230°C for 1 hour in an oven purged with nitrogen to form a coating film with a thickness of 0.1 μm. Subsequently, the coating surface was irradiated with 1,000 J / m of polarized ultraviolet light containing bright lines of 313 nm from a direction tilted 40° relative to the substrate normal using an Hg-Xe lamp and a Glan-Taylor prism. 2 This imparts the ability to align liquid crystals. The same operation is repeated to produce a pair (two pieces) of substrates with liquid crystal alignment films.

[0271] On the outer periphery of the surface of one substrate with a liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is screen-printed. The liquid crystal alignment film surfaces of a pair of substrates are then faced together, and pressed together with the projection directions of the ultraviolet light axes of each substrate onto the substrate surface antiparallel. The adhesive is then thermosetting at 150°C for 1 hour. Next, negative liquid crystal (Merck, MLC-6608) is filled into the gap between the substrates from the liquid crystal injection port, and the liquid crystal injection port is sealed using an epoxy adhesive. Furthermore, to remove the flow alignment during liquid crystal injection, it is heated at 130°C and then slowly cooled to room temperature. Finally, polarizing plates are attached to the outer surfaces of the substrate with their polarization directions orthogonal to each other and at a 45° angle to the projection direction of the ultraviolet light axes of the liquid crystal alignment film onto the substrate surface, thereby manufacturing a vertically aligned liquid crystal display element.

[0272] (3) Evaluation of residual DC / resistance

[0273] For the vertical liquid crystal display element manufactured in (2), the residual DC / resistance was evaluated in the same manner as in (5) of Example 1. The results are shown in Table 3.

[0274] [Example 3]

[0275] The composition of the liquid crystal alignment agent was modified as shown in Table 3. Except for this, the liquid crystal alignment agent (AL-3) was prepared with the same solvent composition and solid content as in Example 2. Furthermore, using the liquid crystal alignment agent (AL-3), the solubility and coatability were evaluated in the same manner as in Example 1, and a vertically aligned liquid crystal display element was manufactured to evaluate the residual DC / resistance. The results are shown in Table 3.

[0276] [Example 4: FFS type liquid crystal display element using photo-alignment method]

[0277] (1) Preparation of liquid crystal alignment agent and evaluation of its solubility and coatability

[0278] The composition of the liquid crystal alignment agent was changed as shown in Table 3. Except for this, the liquid crystal alignment agent (AL-4) was prepared with the same solvent composition and solid content as in Example 1. Furthermore, the solubility and coatability of the liquid crystal alignment agent (AL-4) were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0279] (2) Manufacturing of FFS type liquid crystal display elements using photo-alignment method

[0280] A glass substrate (first substrate) with a planar electrode, an insulating layer, and a comb-shaped electrode sequentially stacked on one side, and a glass substrate (second substrate) without electrodes, facing each other, were prepared. A liquid crystal alignment agent (AL-4) was then applied to the electrode forming surface of the first substrate and one of the substrate surfaces of the second substrate using a spinner, and pre-baked at 80°C for 1 minute. Afterward, the substrate was dried (post-baked) for 30 minutes in a 230°C oven with nitrogen purging, resulting in a coating with an average thickness of 0.1 μm. The obtained coating was then irradiated with 1,000 J / m² of ultraviolet light containing linearly polarized 254 nm bright rays from the substrate normal direction using an Hg-Xe lamp. 2 The photo-alignment process is then performed. Furthermore, the irradiation amount is measured using a photometer with a wavelength of 254 nm as the reference. Subsequently, the photo-aligned coating is heat-treated by heating it in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film.

[0281] Next, for one of the pair of substrates with a liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is screen-printed onto the outer edge of the surface with the liquid crystal alignment film. Then, the substrates are overlapped and pressed together so that the projection direction of the polarization axis on the substrate surface during light irradiation is antiparallel, and the adhesive is thermosetting at 150°C for 1 hour. Subsequently, negative liquid crystal (manufactured by Merck, MLC-6608) is filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port is sealed using an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove the flow alignment during liquid crystal injection, it is heated at 120°C and then slowly cooled to room temperature. Then, a polarizing plate is attached to the outer sides of the substrate of the liquid crystal cell to obtain a liquid crystal display element. Additionally, the post-baked ultraviolet irradiation dose is 100 J / m². 2 ~10,000J / m 2The series of operations are performed by changing the range of UV exposure, thereby producing three or more liquid crystal display elements with different UV exposure amounts. The liquid crystal display element with the best exposure amount (optimal exposure amount) that shows the best orientation characteristics is used for the following evaluation.

[0282] (3) Evaluation of residual DC / resistance

[0283] For the optical FFS type liquid crystal display element manufactured in (2), the residual DC / resistance was evaluated in the same manner as in (5) of Example 1. The results are shown in Table 3.

[0284] [Example 5: FFS type liquid crystal display element using the triboelectric method]

[0285] (1) Preparation of liquid crystal alignment agent and evaluation of its solubility and coatability

[0286] The composition of the liquid crystal alignment agent was changed as shown in Table 3. Except for this, the liquid crystal alignment agent (AL-5) was prepared with the same solvent composition and solid content concentration as in Example 1. Furthermore, the solubility and coatability of the liquid crystal alignment agent (AL-5) were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0287] (2) Manufacturing of FFS type liquid crystal display element using the friction method

[0288] A glass substrate (first substrate) with a planar electrode, an insulating layer, and a comb-shaped electrode sequentially stacked on one side, and a glass substrate (second substrate) without electrodes, are prepared facing each other. Then, a liquid crystal alignment agent (AL-5) prepared above is applied to the electrode forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and pre-baked at 80°C for 1 minute. Afterwards, a coating film with a thickness of 0.1 μm is formed by heating at 230°C for 1 hour in an oven with nitrogen purging. The coating film is then rubbed using a friction machine with rollers wound with nylon cloth, at a roller speed of 1000 rpm, a platform movement speed of 2.5 cm / sec, and a bristle indentation length of 0.4 mm. Afterwards, it is ultrasonically cleaned in ultrapure water for 1 minute, and then dried in a clean oven at 100°C for 10 minutes, thereby obtaining a pair of substrates with a liquid crystal alignment film.

[0289] On the outer periphery of the side of one of the pair of substrates with the liquid crystal alignment film, an epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is screen-printed onto it. The substrates are then overlapped and pressed together with their respective liquid crystal alignment film surfaces facing each other, and the adhesive is allowed to harden. Next, nematic liquid crystal (manufactured by Merck, MLC-6608) is filled between the two substrates through the liquid crystal injection port. The liquid crystal injection port is then sealed using an acrylic photocurable adhesive, and polarizing plates are attached to both outer surfaces of the substrates, thereby manufacturing a triboelectric FFS type liquid crystal display element.

[0290] (3) Evaluation of residual DC / resistance

[0291] For the triboelectric FFS type liquid crystal display element manufactured in (2), the residual DC / resistance was evaluated in the same manner as in (5) of Example 1. The results are shown in Table 3.

[0292] [Table 3]

[0293]

[0294] As is clear from Table 3, in Examples 1 to 8, 12, and 13, which used liquid crystal alignment agents containing polymer [P], the solubility, residual DC properties, and coatability of the polymers were all good or acceptable. Among them, any evaluation of Examples 1 to 6 was good and particularly excellent compared to Example 7, which used a polymer (PA-7) containing thermally detachable groups in structural units (B), and Example 8, which used a polymer (PA-8) with an increased ratio of structural units (B) relative to structural units (A).

[0295] Furthermore, in Examples 9 to 11, which used liquid crystal alignment agents comprising polymers [P1] and [P2], the solubility, residual DC properties, and coatability of the polymers were all good or acceptable. Among these, the residual DC properties of the liquid crystal alignment agents in Examples 9 to 11 were deemed acceptable. Based on these results, it can be said that the morphology of the same polymer comprising both structural unit (A) and structural unit (B) is significantly better than that of polymers [P1] containing structural unit (A) and polymers [P2] containing structural unit (B) separately, demonstrating a higher and superior improvement in residual DC properties.

[0296] In contrast, in Comparative Examples 1 to 7, which used polymers that did not contain either structural unit (A) or structural unit (B), at least one of the following evaluations was unsatisfactory: solubility, low residual DC properties, and coatability. Specifically, in Comparative Example 1, which used a polymer that did not contain a structural unit with a basic group, the residual DC properties were unsatisfactory; in Comparative Example 2, which used a polymer that did not contain a structural unit with an acidic group, all evaluations were unsatisfactory. Furthermore, in Comparative Examples 3 and 7, which used polymers containing structural units with unprotected carboxyl groups, and in Comparative Example 4, which used polymers containing structural units with carboxyl groups protected by tert-butoxycarbonyl groups, coatability was unsatisfactory. Moreover, in Comparative Examples 5 and 6, which used polymers containing structural units with carboxyl groups protected by bulky groups, both residual DC properties and coatability were unsatisfactory. It was also considered that when a relatively small group, such as a tert-butoxycarbonyl group, was used as a protecting group, the volume exclusion effect was insufficient, resulting in a slight decrease in the solubility of the polymer and insufficient coatability. Furthermore, it is believed that when a large-volume base is used as a protective base (Comparative Example 5, Comparative Example 6), the charge transport caused by acid-base interaction is insufficient. In addition, due to the influence of the detached protective base, the residual DC properties and coatability are insufficient.

[0297] In addition, in Comparative Examples 8 and 9, which are liquid crystal alignment agents comprising polymers including polymers having unprotected carboxyl groups and polymers having structural units (B) [P2], the solubility and low residual DC properties of the polymers were rated as acceptable, while the coatability was rated as poor.

[0298] Based on the above, it is clear that by using a liquid crystal alignment agent that contains structural units (A) and (B) in the polymer composition, a liquid crystal alignment film with good solubility, low residual DC properties, and good coatability of the polymer can be manufactured.

Claims

1. A liquid crystal alignment agent comprising a polymeric component, the polymeric component is at least any one of the following (I) and (II): (I) comprising a polymer [P] containing a structural unit (A) having at least one selected from the group consisting of a structure represented by the following formula (Y-1), an acetal ester structure of a carboxylic acid, and a ketal ester structure of a carboxylic acid as a partial structure represented by the following formula (1), and a structural unit (B) derived from at least one selected from the group consisting of a compound represented by the following formula (3-1), a compound represented by the following formula (3-2), and a compound represented by the following formula (3-3); (II) comprising a polymer [P1] containing the structural unit (A), and a polymer [P2] containing the structural unit (B), In formula (1), A 1 is a carbon number 5 or more monovalent chain hydrocarbon group or alicyclic hydrocarbon group, or a carbon number 3 or more monovalent group having -O- between carbon-carbon bonds of the chain hydrocarbon group or alicyclic hydrocarbon group; "represents a bond to a carbon atom, In formula (Y-1), R 3 and R 4 are each independently an alkyl group, or represent R 3 and R 4 are combined with each other and the carbon atom to which R 3 and R 4 are bonded together form a ring structure having 4 or more carbons; R 5 is an alkyl group; wherein, In the case where R 3 and R 4 are both methyl groups, R 5 is a carbon number of 2 or more. " indicates a bond. In equation (3-1), B 1 and B 3 Each can be independently a divalent aromatic hydrocarbon group, a divalent nitrogen-containing heterocyclic group, or a -Z group. 1 -OZ 2 -, where Z 1 and Z 2 Each is independently a divalent aromatic hydrocarbon group; B 2 It is a single bond, a divalent hydrocarbon group, or has a carbon-carbon bond selected from -O- or -NR between the carbon-carbon bonds of the hydrocarbon group. 2 -、-CO-NR 2 -and-NR 2 -CO-, where R 2 A divalent group consisting of at least one of the group consisting of a hydrogen atom or a monovalent organic group; X 1 and X 2 Each is independently a divalent nitrogen-containing heterocyclic group, or a divalent group represented by formula (2); L 1 and L 2 Each can be a single bond or a divalent linker, and each can be an integer from 0 to 2. In formula (3-2), B 4 is a divalent organic group; Y 1 is a monovalent group having at least one selected from the group consisting of a nitrogen-containing heterocycle and a moiety represented by the formula (2). In formula (3-3), B 5 is a divalent nitrogen-containing aromatic ring group.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer [P] is at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, a polyimide, and an addition polymer.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the polymer [P1] and the polymer [P2] are at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, a polyimide, and an addition polymer.

4. The liquid crystal aligning agent according to claim 3, wherein the polymer [P1] and the polymer [P2] are at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide.

5. The liquid crystal aligning agent according to claim 3, wherein one of the polymer [P1] and the polymer [P2] is at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide, and the other is an addition polymer.

6. The liquid crystal aligning agent according to claim 1 or 2, wherein the total amount of the structural unit (A) and the structural unit (B) possessed by the polymer [P] is 50 mol% or less relative to the total amount of structural units derived from monomers possessed by the polymer [P], the ratio of the structural unit (A) and the structural unit (B) possessed by the polymer [P] is 1:0.025 to 3 in terms of a molar ratio of structural unit (A):structural unit (B).

7. The liquid crystal aligning agent according to claim 1 or 2, wherein the structural unit (A) is a structural unit derived from a diamine having a partial structure represented by the formula (1), the polymer [P] has a structural unit derived from an alicyclic tetracarboxylic dianhydride.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein at least one of the polymer [P1] and the polymer [P2] is at least one selected from the group consisting of a polyamic acid, a polyamic acid ester, and a polyimide, and has a structural unit derived from an alicyclic tetracarboxylic dianhydride.

9. A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 8.

10. A liquid crystal element comprising the liquid crystal alignment film according to claim 9.

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