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

Abstract

The invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal element. The invention relates to a liquid crystal aligning agent, which contains a first polymer and a second polymer as imide polymers selected from a group consisting of polyamide acid, polyamide acid ester and polyimide, the first polymer contains a structural unit (I) derived from a diamine having a partial structure represented by formula (1) and a structural unit (T) derived from a substituted cyclobutane tetracarboxylic acid dianhydride, and the content ratio of the structural unit (T) is 75 mol% or more with respect to the total amount of structural units derived from a tetracarboxylic acid derivative contained in the first polymer. The second polymer is a polymer that is different from the first polymer and contains a structural unit (II) derived from a diamine having a partial structure represented by formula (2). And D1 and D2 independently represent a monovalent organic group having 5 or more carbon atoms. # imgabs0 #

Description

Technical Field

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

[0002] The liquid crystal element includes a liquid crystal alignment film having a function of controlling the alignment of liquid crystal molecules in the liquid crystal layer. The liquid crystal alignment film is generally formed on a substrate by applying a liquid crystal alignment agent prepared by dissolving a polymer in a solvent to a substrate surface and preferably heating the substrate.

[0003] In recent years, with the high precision or multi-purpose of liquid crystal elements, liquid crystal alignment films are required to be able to exhibit various properties such as optical properties such as liquid crystal orientation or transmittance, electrical properties such as voltage holding rate, and mechanical properties that are not damaged by physical pressure such as transmission or knocking in a well-balanced manner. In addition, in order to form a liquid crystal alignment film that can simultaneously exhibit multiple functions such as optical properties, electrical properties, and mechanical properties, the following contents are performed: a liquid crystal alignment agent is prepared by using a plurality of compounds having respective functions and combining these plurality of compounds (for example, refer to Patent Document 1).

[0004] In addition, in recent years, the following content has been proposed: by making the liquid crystal alignment agent contain a polyimide obtained by using a diamine having an amide bond or a urea bond, the liquid crystal orientation of the liquid crystal element is improved (for example, refer to Patent Document 2). Furthermore, the following content has been proposed: by making the liquid crystal alignment agent contain a polyimide obtained by using a diamine having a nitrogen-containing heterocyclic structure, the electrical characteristics of the liquid crystal element are improved (for example, refer to Patent Document 3).

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] International Publication No. 2020 / 158818

[0008] [Patent Document 2] Japanese Patent Application Publication No. 2018-200439

[0009] [Patent Document 3] International Publication No. 2018 / 062440 Summary of the invention

[0010] [Problems to be solved by the invention]

[0011] It is believed that by combining a polymer obtained by using a diamine (non-basic diamine) having an amide bond or a urea bond, and a polymer obtained by using a diamine (basic diamine) having an imidazole ring structure or a pyridine ring structure to prepare a liquid crystal alignment agent, the liquid crystal orientation and electrical properties are taken into account. However, in the case of combining these two polymers to prepare a liquid crystal alignment agent, the mechanical properties of the liquid crystal alignment film formed by the liquid crystal alignment agent are insufficient, and there is room for further improvement. In particular, in recent years, the mechanical properties of the film in the liquid crystal element have been valued, and it is required to improve the mechanical properties of the film together with the liquid crystal orientation and electrical properties as basic properties.

[0012] The present invention has been made in view of the above problems, and a main object of the present invention is to provide a liquid crystal aligning agent which can form a liquid crystal element having excellent liquid crystal orientation and electrical characteristics and obtain a liquid crystal aligning film having excellent mechanical characteristics.

[0013] [Technical means to solve the problem]

[0014] According to the present invention, the following means are provided.

[0015] [1] A liquid crystal aligning agent comprising a first polymer and a second polymer as imide polymers selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, wherein the first polymer comprises a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), wherein the content ratio of the structural unit (T) is 75 mol% or more relative to the total amount of structural units derived from tetracarboxylic acid derivatives contained in the first polymer, and the second polymer is a polymer different from the first polymer and comprises a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2).

[0016] [Chemistry 1]

[0017]

[0018] (In formula (1), D 1 It is a monovalent organic group having 5 or more carbon atoms. 1 is a single bond, -O- or -NR 3a -. R 2 is a single bond or -NR 3b -. R 3a and R 3b are independently a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. 4 and R 5 are independently substituted or unsubstituted divalent hydrocarbon groups or divalent heterocyclic groups. "*" represents a bond)

[0019] [Chemistry 2]

[0020]

[0021] (In formula (2), D 2 is a monovalent organic group having 5 or more carbon atoms. d is 1 or 2. When d is 1, R 6 and R 7 Independently of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atom to which it is bonded together forms a monocyclic or condensed heterocyclic structure. When d is 2, R 6 and R 7 Medium R 6 is ">C(R 10 )-* 1 " represents a trivalent group, a trivalent alicyclic group or a trivalent aromatic ring group (wherein "* 1 ” indicates the bond on the nitrogen side), R 7 For "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atoms bonded together form a monocyclic or condensed heterocyclic structure. 10 , R 11 and R 12 are independently a hydrogen atom, a monovalent hydrocarbon group or a substituent. 8 is a hydrogen atom or an organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1. Where a+b+c=2 is satisfied. 6 and R 7 Combined with R 6 and R 7 In the case of a monocyclic or condensed heterocyclic structure formed by the nitrogen atom to which the bond is attached, a=1, b=1 and c=0. "*" indicates a bond)

[0022] [Chemistry 3]

[0023]

[0024] (In formula (3), R 15 , R 16 , R 17 and R 18are independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and having a fluorine atom, or a phenyl group. 15 , R 16 , R 17 and R 18 at least one of which is a group different from a hydrogen atom)

[0025] [2] A liquid crystal alignment film formed using the liquid crystal aligning agent according to [1].

[0026] [3] A liquid crystal element comprising the liquid crystal alignment film according to [2].

[0027] [Effects of the Invention]

[0028] According to the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having excellent dynamic characteristics can be formed while making the liquid crystal orientation and electrical characteristics of a liquid crystal element excellent. DETAILED DESCRIPTION

[0029] Liquid crystal alignment agent

[0030] The liquid crystal aligning agent of the present disclosure contains two or more imide polymers selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. These two or more imide polymers include the first polymer and the second polymer shown below.

[0031] The first polymer is a polymer containing a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), wherein the content ratio of the structural unit (T) is 75 mol% or more relative to the total amount of the structural units derived from the tetracarboxylic acid derivative contained in the first polymer

[0032] The second polymer is a polymer that contains a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2) and is different from the first polymer.

[0033] [Chemistry 4]

[0034]

[0035] (In formula (1), D 1 It is a monovalent organic group having 5 or more carbon atoms. 1 is a single bond, -O- or -NR 3a -. R 2 is a single bond or -NR 3b -. R 3a and R 3bare independently a hydrogen atom or a monovalent organic group having 1 or more carbon atoms. 4 and R 5 are independently substituted or unsubstituted divalent hydrocarbon groups or divalent heterocyclic groups. "*" represents a bond)

[0036] [Chemistry 5]

[0037]

[0038] (In formula (2), D 2 is a monovalent organic group having 5 or more carbon atoms. d is 1 or 2. When d is 1, R 6 and R 7 Independently of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atom to which it is bonded together forms a monocyclic or condensed heterocyclic structure. When d is 2, R 6 and R 7 Medium R 6 is ">C(R 10 )-* 1 " represents a trivalent group, a trivalent alicyclic group or a trivalent aromatic ring group (wherein "* 1 ” indicates the bond on the nitrogen side), R 7 For "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atoms bonded together form a monocyclic or condensed heterocyclic structure. 10 , R 11 and R 12 are independently a hydrogen atom, a monovalent hydrocarbon group or a substituent. 8 is a hydrogen atom or an organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1. Where a+b+c=2 is satisfied. 6 and R 7 Combined with R 6 and R 7 In the case of a monocyclic or condensed heterocyclic structure formed by the nitrogen atom to which the bond is attached, a=1, b=1 and c=0. "*" indicates a bond)

[0039] [Chemistry 6]

[0040]

[0041] (In formula (3), R 15 , R 16 , R 17 and R 18 are independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and having a fluorine atom, or a phenyl group. 15 , R 16 , R 17 and R 18 at least one of which is a group different from a hydrogen atom)

[0042] Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure and the components arbitrarily formulated as needed (hereinafter also referred to as "other components") are described. In addition, in this specification, the numerical range described using "~" means that the numerical values ​​described before and after "~" are included as the lower limit and upper limit. Unless each component is specifically mentioned, one may be used alone or two or more may be used in combination.

[0043] Here, in this specification, the so-called "hydrocarbon group" means a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. The so-called "chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group that do not contain a cyclic structure but only a chain structure in the main chain. Among them, the chain hydrocarbon group may be saturated or unsaturated. The so-called "alicyclic hydrocarbon group" refers to a hydrocarbon group that only contains alicyclic hydrocarbon structures as a ring structure but does not contain aromatic ring structures. Among them, the alicyclic hydrocarbon group does not need to contain only alicyclic hydrocarbon structures, and also includes a group having a chain structure in a part thereof. The so-called "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. Among them, the aromatic hydrocarbon group does not need to contain only aromatic ring structures, and may also contain a chain structure or an alicyclic hydrocarbon structure in a part thereof. "Aromatic ring" means an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The so-called "organic group" refers to an atomic group formed by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound).

[0044] The so-called "main chain" of a polymer refers to the part of the "trunk" of the chain containing the longest atoms in the polymer. The part of the "trunk" may contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain of the polymer. The so-called "side chain" refers to the part branching from the "trunk" of the polymer. "Tetracarboxylic acid derivatives" are terms that include tetracarboxylic dianhydride, tetracarboxylic acid diesters and tetracarboxylic acid diester dihalides.

[0045] The liquid crystal alignment agent of the present disclosure contains two or more imide-based polymers selected from the group consisting of polyamic acid, polyamic acid ester and polyimide as polymer components. These two or more imide-based polymers can contain a polymer (first polymer) having a structural unit (I) and a polymer (second polymer) having a structural unit (II). Therefore, there is no particular limitation on the structural units other than the structural unit (I) in the structural unit constituting the first polymer and the structural units other than the structural unit (II) in the structural unit constituting the second polymer. For example, the first polymer may have structural unit (I) and structural unit (II) together. In addition, the second polymer may have structural unit (II) and structural unit (I) together. As long as the monomer compositions are different from each other, the first polymer and the second polymer may also have structural unit (I) and structural unit (II) together.

[0046] As preferable aspects of the first polymer and the second polymer contained in the liquid crystal aligning agent of the present disclosure, the following [1] and [2] can be mentioned.

[0047] [1] An aspect in which the first polymer has the structural unit (I) but does not have the structural unit (II), and the second polymer has the structural unit (II) and the content ratio of the structural unit (I) is not more than a predetermined value.

[0048] [2] An aspect in which the first polymer has the structural unit (I) and the structural unit (II), the second polymer has the structural unit (II), and the content ratio of the structural unit (I) is not more than a predetermined value.

[0049] Hereinafter, the first polymer and the second polymer will be described in detail respectively.

[0050] <First polymer>

[0051] The first polymer contains a structural unit (I) derived from a diamine (hereinafter also referred to as a "first specific diamine") having a partial structure represented by the formula (1). 1 The monovalent organic group having 5 or more carbon atoms represented by , includes a monovalent hydrocarbon group having 5 to 20 carbon atoms, a monovalent leaving group having 5 to 20 carbon atoms, etc. Among these, examples of the monovalent hydrocarbon group having 5 to 20 carbon atoms include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. 1 In the case of a monovalent hydrocarbon group having 5 to 20 carbon atoms, the above-mentioned alkyl group having 5 to 10 carbon atoms, cyclohexyl group or phenyl group is preferred.

[0052] D 1 The leaving group represented is a group that is detached by heat, light, etc. and replaced by a hydrogen atom. 1The represented detachable group is preferably a group that is detached by heat and replaced by a hydrogen atom (hereinafter also referred to as a "thermal detachable group"). Specific examples of the thermal detachable group include tert-butoxycarbonyl (Boc group), benzyloxycarbonyl, 1,1-dimethyl-2-halogenoethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, 9-fluorenylmethyloxycarbonyl (F-moc group), etc.

[0053] Regarding D in the formula (1) 1 From the viewpoint of suppressing the separation of the first polymer and the second polymer contained in the liquid crystal alignment agent and obtaining a liquid crystal alignment film having excellent mechanical properties, a thermally detachable group is preferred. From the viewpoint of having excellent thermal detachability and being able to reduce the residual amount of the detached structure in the film, a Boc group is particularly preferred.

[0054] R 1 is a single bond, -O- or -NR 3a -, R 2 is a single bond or -NR 3b -. In R 3a or R 3b In the case of a monovalent organic group having 1 or more carbon atoms, examples of the monovalent organic group include monovalent hydrocarbon groups having 1 to 20 carbon atoms, monovalent leaving groups, and the like. Among these, examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. 3a or R 3b In the case of a monovalent hydrocarbon group having 1 to 20 carbon atoms, R 3a or R 3b R is preferably an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group or a phenyl group. 3a or R 3b Specific examples and preferred examples of the leaving group include: 1 In the case of a leaving group, R is the same group as described in the specific examples and preferred examples. 3a and R 3b Among the above, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, a phenyl group or a thermally detachable group is preferred, and a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a Boc group is more preferred.

[0055] R 1 Preferably a single bond or -NR 3a -. R 2 Preferred is a single bond.

[0056] R 4 and R 5 are substituted or unsubstituted divalent hydrocarbon groups or divalent heterocyclic groups. 4 or R 5In the case of a divalent hydrocarbon group (i.e., an unsubstituted divalent hydrocarbon group), examples of the divalent hydrocarbon group include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic hydrocarbon group having 6 to 20 carbon atoms. Specific examples of the chain hydrocarbon group having 1 to 20 carbon atoms include a linear or branched saturated chain hydrocarbon group, and a linear or branched unsaturated chain hydrocarbon group. 4 or R 5 In the case of having a substituent (i.e., in the case of a substituted divalent hydrocarbon group), examples of the substituent include a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, a nitro group, an alkoxy group, etc. In addition, the expression "substituted or unsubstituted divalent hydrocarbon group" refers to a divalent hydrocarbon group and a divalent group in which any hydrogen atom in the divalent hydrocarbon group is substituted.

[0057] A heterocyclic group is a group obtained by removing two hydrogen atoms from a substituted or unsubstituted heterocyclic ring. 4 or R 5 When it is a divalent heterocyclic group, the heterocyclic ring possessed by the heterocyclic group may be an aliphatic heterocyclic ring or an aromatic heterocyclic ring. From the viewpoint of obtaining a liquid crystal element showing good liquid crystal orientation and electrical characteristics, R 4 or R 5 The divalent heterocyclic group represented is preferably an aromatic heterocyclic group, and more preferably a nitrogen-containing aromatic heterocyclic group. Specific examples of the heterocyclic ring possessed by the nitrogen-containing aromatic heterocyclic group include a pyridine ring, a pyridazine ring, and a pyrimidine ring.

[0058] From the viewpoint of obtaining a liquid crystal element with further improved liquid crystal orientation, it is preferred that R in the formula (1) 4 and R 5 One or both of them have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group and R 1 or R 2 That is, preferably, in the formula (1), R 4 having a substituted or unsubstituted divalent chain hydrocarbon group, R 4 The chain hydrocarbon group and R 1 Bond, or R 5 having a substituted or unsubstituted divalent chain hydrocarbon group, R 5 The chain hydrocarbon group and R 2 In these cases, the chain hydrocarbon group is preferably an alkanediyl group, and more preferably a straight-chain alkanediyl group. 1 or R 2 The number of carbon atoms in the adjacent chain hydrocarbon groups is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 to 6.

[0059] From the viewpoint of further improving the liquid crystal orientation of the liquid crystal element, R 4 and R 5 have a substituted or unsubstituted divalent straight-chain hydrocarbon group, R 4 A substituted or unsubstituted divalent straight-chain hydrocarbon group and R 1 Bond, R 5 A substituted or unsubstituted divalent straight-chain hydrocarbon group and R 2 bond, and with "-R 1 -CO-ND 1 -R 2 The total number of carbon atoms of the substituted or unsubstituted divalent linear hydrocarbon groups adjacent to both ends of the group represented by "-" is 4 or more.

[0060] The first specific diamine may have only one "-R 1 -CO-ND 1 -R 2 The group represented by "-" may also include "-R" in the partial structure represented by the formula (1). 1 -CO-ND 1 -R 2 -" has two or more groups. Regarding the "-R 1 -CO-ND 1 -R 2 The number of groups represented by "-" includes the number of groups represented by "-R" in the partial structure represented by the formula (1). 1 -CO-ND 1 -R 2 The number of the groups represented by "-" is, for example, 1 to 4.

[0061] The first polymer may have a partial structure represented by the formula (1) in the main chain of the polymer or in the side chain. In terms of high improvement in liquid crystal orientation and electrical properties, it is preferred that the first polymer has a partial structure represented by the formula (1) in the main chain of the polymer.

[0062] Specific examples of the first specific diamine include compounds represented by the following formulae (1-1) to (1-9). In addition, "Boc" in the formula represents a tert-butoxycarbonyl group (Boc group) (the same applies hereinafter).

[0063] [Chemistry 7]

[0064]

[0065] The first polymer has a structural unit (T) derived from a compound represented by the formula (3) (hereinafter also referred to as "substituted cyclobutane tetracarboxylic dianhydride"). The first polymer has a structural unit derived from a substituted cyclobutane tetracarboxylic dianhydride, and a liquid crystal element showing good liquid crystal orientation and electrical properties can be obtained by a photo-alignment method while improving the solubility of the first polymer, which is preferred in terms of the above aspect.

[0066] Specific examples of substituted cyclobutanetetracarboxylic dianhydride include compounds represented by the following formulas (3-1) to (3-9). Among these, the compound represented by the following formula (3-2) (1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride) is particularly preferred because of excellent photo-alignment properties.

[0067] [Chemistry 8]

[0068]

[0069] Relative to the total amount of the structural unit derived from the tetracarboxylic acid derivative possessed by the first polymer, the ratio of the structural unit (T) in the first polymer is 75 mol% or more. If the ratio of the structural unit (T) in the first polymer is less than 75 mol%, in the case of the pretilt angle of the liquid crystal given by the photo-orientation method, the pretilt angle is insufficient, and it is feared that the orientation of the liquid crystal will be reduced. Relative to the total amount of the structural unit derived from the tetracarboxylic acid derivative possessed by the first polymer, the ratio of the structural unit (T) in the first polymer is more preferably 80 mol% or more, and further preferably 90 mol% or more, and further more preferably 95 mol% or more.

[0070] The method for synthesizing the first polymer is not particularly limited. The first polymer can be obtained, for example, by a method including the step of polycondensing a tetracarboxylic acid derivative including substituted cyclobutanetetracarboxylic dianhydride and a diamine compound including the first specific diamine.

[0071] (Polyamic acid)

[0072] When the first polymer is a polyamic acid, the polyamic acid can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound.

[0073] Tetracarboxylic dianhydride

[0074] When the first polymer is a polyamic acid, only substituted cyclobutane tetracarboxylic dianhydride may be used in the synthesis of the first polymer, or tetracarboxylic dianhydride different from substituted cyclobutane tetracarboxylic dianhydride (hereinafter also referred to as "other tetracarboxylic dianhydride") may be used. As other tetracarboxylic dianhydrides, for example, aliphatic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, etc. may be cited. Aliphatic tetracarboxylic dianhydride is a term that includes chain tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride.

[0075] As specific examples of other tetracarboxylic dianhydrides, as chain tetracarboxylic dianhydrides, 1,2,3,4-butanetetracarboxylic dianhydride and the like can be cited;

[0076] Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, and cyclohexanetetracarboxylic dianhydride.

[0077] Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol ditrimellityl anhydride, 4,4'-carbonyl diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride. In addition, as the tetracarboxylic dianhydride, the tetracarboxylic dianhydride described in Japanese Patent Application Laid-Open No. 2010-97188 can be used.

[0078] ·Diamine compounds

[0079] The diamine compound used in the synthesis of the first polymer may be the first specific diamine alone, or a diamine different from the first specific diamine (hereinafter also referred to as "first other diamine") may be used in combination. Examples of the first other diamine include aliphatic diamines, aromatic diamines, and diaminoorganosiloxanes. Aliphatic diamines include chain diamines and alicyclic diamines.

[0080] Specific examples of the first other diamine include, as chain diamines, meta-xylylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, etc.; as alicyclic diamines, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc.;

[0081] Examples of the aromatic diamine include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 4-aminophenyl-4-aminobenzoate, 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, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]adipic acid, 1,4-bis(4-aminophenyl)-piperazine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane , 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(phenylenediisopropylidene)dianiline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-[4,4'-propane-1,3-diylbis(piperidin-1,4-diyl)]diphenylamine, 4,4'-diaminobenzanilide, 4,4'-diaminostilbene, 1,4-bis(4-aminophenyl)-piperazine, bis[2-(4-aminophenyl)ethyl]adipic acid, 4,4'-diaminodiphenylethylurea, 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 and other main chain diamines;

[0082] Dodecyloxy-2,4-diaminobenzene, pentadecyloxy-2,4-diaminobenzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryloxy-3,5-diaminobenzoate, 3,5-diaminobenzoate Side chain diamines such as cholesteryl aminobenzoate, lanostanyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 5ξ-cholestane-3-yl 3,5-diaminobenzoate, and compounds represented by the following formula (E-1);

[0083] [Chemistry 9]

[0084]

[0085] (In formula (E-1), X I and X II Each independently represents a single bond, -O-, *-COO- or *-OCO- (wherein "*" represents a bond to the diaminophenyl side). I It is an alkanediyl group having 1 to 3 carbon atoms. II is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a1 is 0 or 1. b1 is an integer from 0 to 3. c1 is an integer from 0 to 2. d1 is 0 or 1. (where 1≦a1+b1+c1≦3)

[0086] Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and other diamines described in JP-A-2010-97188 can be used. In addition, as the first other diamine, a diamine having a partial structure represented by formula (2) can be used.

[0087] Examples of the compound represented by formula (E-1) include compounds represented by the following formulae (E-1-1) to (E-1-4), and the like.

[0088] [Chemistry 10]

[0089]

[0090] From the viewpoint of obtaining a liquid crystal element with excellent liquid crystal orientation, the first polymer preferably has 2 mol% or more of the structural unit (I) relative to the structural unit derived from the diamine compound possessed by the first polymer. The content ratio of the structural unit (I) is more preferably 5 mol% or more, and further preferably 10 mol% or more relative to the total amount of the structural unit derived from the diamine compound possessed by the first polymer. In addition, the content ratio of the structural unit (I) in the first polymer is preferably 80 mol% or less, more preferably 70 mol% or less, and further preferably 60 mol% or less relative to the total amount of the structural unit derived from the diamine compound possessed by the first polymer.

[0091] It is preferred that the first polymer includes structural units derived from four or more diamine compounds including structural units (I). By constituting the first polymer with four or more diamine compounds, the photodecomposition products generated by the light irradiation of the coating film or liquid crystal unit formed by the liquid crystal aligning agent can be suppressed from precipitating in the liquid crystal, and the liquid crystal orientation (orientation reliability, orientation uniformity) can be further improved. In the case where the first polymer includes structural units (I) and is composed of four or more diamine compounds, the diamine compound constituting the first polymer is preferably at least one selected from the group consisting of diamines having a partial structure represented by the following formula (5) and diamines having a partial structure represented by the formula (2) in addition to the first specific diamine. The diamine having a partial structure represented by the following formula (5) has high sensitivity to light, and by using it in combination with the compound represented by the formula (3) (substituted cyclobutane tetracarboxylic dianhydride), the sensitivity can be improved, which is preferred in terms of the above aspect.

[0092] [Chemistry 11]

[0093]

[0094] (In formula (5), Ar 3 and Ar 4 Z is independently substituted or unsubstituted phenylene, naphthalene diyl, biphenylene, pyridine diyl, pyrimidine diyl or pyrazine diyl. 1 and Z 2 are independently single bonds, -NR 20 -、-O-、-S-、-CO-、* 1 -NH-CO-,* 1 -CO-NH-,* 1 -NH-CO-NH-, * 1 -CO-O- or * 1 -O-CO-. Among them, Z 1 and Z 2 It will not become a single bond at the same time. 20 It is a hydrogen atom or a monovalent organic group. 1 " indicates that the 3 or Ar 4 The bonding key. 1 For-NR 22 -、-O-、-S-、-CO-、* 2 -NH-CO-,* 2 -CO-NH-, -NH-CO-NH-, * 2 -CO-O- or * 2 -O-CO-. R 22 It is a hydrogen atom or a monovalent organic group. 2 " indicates that1 The bond of B 1 It is a divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. 2 is a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms. n is an integer of 0 to 3. When n is 2 or 3, a plurality of B 1 Same or different, multiple L 1 Same or different. "*" indicates a bond)

[0095] In the formula (5), Z 1 or Z 2 For-NR 20 -In the case of R 20 The monovalent organic group represented by R includes a monovalent hydrocarbon group having 1 to 10 carbon atoms and a monovalent leaving group. 20 A hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group is preferred, and a thermally detachable group is more preferred.

[0096] From the viewpoint of improving the photoreactivity of the first polymer when a photo-alignment site (preferably a substituted cyclobutane ring structure) is introduced into the main chain of the first polymer, Z 1 and Z 2 It is preferred to increase the adjacent aromatic group (Ar 3 ,Ar 4 ) is an electron-donating group with an electron density of . Specifically, Z 1 and Z 2 At least one of them is -O-, -S- or -NR 24 -(R 24 is a hydrogen atom or a monovalent organic group), more preferably -O- or -NR 24 -. In addition, from the above viewpoint, Z is more preferably 1 and Z 2 Both are -O-, -S- or -NR 24 -, and more preferably -O- or -NR 24 -. R 24 A hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group is preferred, and a thermally detachable group is more preferred.

[0097] As B 1 Examples of the divalent aliphatic hydrocarbon group represented by include a chain hydrocarbon group having 1 to 20 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. 2 Examples of the divalent aliphatic hydrocarbon group include a chain hydrocarbon group having 3 to 20 carbon atoms and an alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0098] In terms of being able to form a liquid crystal alignment film with high improvement effects on mechanical properties and electrical properties, B 1The divalent aliphatic hydrocarbon group represented is preferably a divalent straight-chain or branched hydrocarbon group having 1 to 10 carbon atoms, more preferably a straight-chain alkanediyl group having 1 to 5 carbon atoms, and still more preferably a straight-chain alkanediyl group having 1 to 3 carbon atoms.

[0099] From the viewpoint of obtaining a liquid crystal element showing good liquid crystal orientation, B 2 The divalent aliphatic hydrocarbon group represented is preferably a divalent linear or branched chain hydrocarbon group having 3 to 10 carbon atoms. In terms of forming a liquid crystal alignment film having a high effect of improving mechanical properties and electrical properties, B 2 More preferably, it is a linear alkanediyl group having 3 to 10 carbon atoms. From the viewpoint of obtaining a liquid crystal element showing good liquid crystal orientation, B 2 The carbon number of is preferably 8 or less, more preferably 6 or less, and further preferably 5 or less.

[0100] In L 1 For-NR 22 -In the case of R 22 Specific examples and preferred examples of the monovalent organic group represented by include the following: 20 The same group as described in the monovalent organic group represented by L 1 Preferably -NR 22 -、-O-、* 2 -NH-CO-, -NH-CO-NH-, * 2 -CO-O- or * 2 -O-CO-, more preferably -NR 22 -.

[0101] n is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.

[0102] Specific examples of the diamine having a partial structure represented by the above formula (5) include compounds represented by the following formulas (5-1) to (5-11), respectively.

[0103] [Chemistry 12]

[0104]

[0105] (In formula (5-1) to formula (5-11), k is an integer of 3 to 10)

[0106] When a diamine having a partial structure represented by the formula (5) is used in the synthesis of the first polymer, the content ratio of the structural unit derived from the diamine having the partial structure represented by the formula (5) (hereinafter also referred to as "structural unit (III)") in the first polymer is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more, relative to the total amount of structural units derived from diamine compounds possessed by the first polymer. In addition, the content ratio of the structural unit (III) in the first polymer is preferably 90 mol% or less, more preferably 80 mol% or less, relative to the total amount of structural units derived from diamine compounds possessed by the first polymer. In addition, the compounds represented by the formula (5-3), the formula (5-6), the formula (5-7) and the formula (5-9) are also equivalent to the diamine having the partial structure represented by the formula (2).

[0107] When a diamine having a partial structure represented by the formula (2) is used in the synthesis of the first polymer, the content of the structural unit (II) in the first polymer is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more, relative to the total amount of structural units derived from the diamine compound in the first polymer. In addition, the content of the structural unit (II) in the first polymer is preferably 50 mol% or less, more preferably 40 mol% or less, relative to the total amount of structural units derived from the diamine compound in the first polymer.

[0108] Synthesis of polyamic acid

[0109] Polyamic acid can be obtained by reacting the tetracarboxylic dianhydride as described above with a diamine compound and a molecular weight modifier as needed. The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of polyamic acid is preferably a ratio in which the anhydride group of the tetracarboxylic dianhydride is 0.2 to 2 equivalents relative to 1 equivalent of the amino group of the diamine compound. As a molecular weight modifier, for example, acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate, etc. The ratio of the molecular weight modifier used is preferably set to 20 parts by mass or less relative to a total of 100 parts by mass of the tetracarboxylic dianhydride and the diamine compound used.

[0110] The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, and the reaction time is preferably 0.1 hour to 24 hours.

[0111] As the organic solvent used in the reaction, for example, there can be mentioned: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. Particularly preferred organic solvents are preferably selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamide, metacresol, dimethyl phenol and halogenated phenol as solvents, or a mixture of one or more of these and other organic solvents (for example, butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount (a) of the organic solvent used is preferably set to an amount that makes the total amount (b) of the tetracarboxylic dianhydride and the diamine compound 0.1 mass % to 50 mass % relative to the total amount (a+b) of the reaction solution.

[0112] In this manner, a reaction solution in which the polyamic acid is dissolved is obtained. The reaction solution may be directly used for the preparation of the liquid crystal aligning agent, or the polyamic acid contained in the reaction solution may be separated and then used for the preparation of the liquid crystal aligning agent.

[0113] (Polyamic acid ester)

[0114] When the first polymer is polyamic acid ester, the polyamic acid ester as the first polymer can be obtained, for example, by the following method, etc.: [I] a method of reacting a polyamic acid having a structural unit (I) with an esterifying agent; [II] a method of reacting a tetracarboxylic acid diester with a diamine compound containing a first specific diamine; [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a first specific diamine. The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester is dissolved can be directly used for the preparation of a liquid crystal aligning agent, or the polyamic acid ester contained in the reaction solution can be separated and used for the preparation of a liquid crystal aligning agent.

[0115] (Polyimide)

[0116] When the first polymer is a polyimide, the polyimide as the first polymer can be obtained, for example, by dehydrating and ring-closing a polyamic acid having the structural unit (I) and imidizing it. The imidization rate of the polyimide is preferably 20% to 90%, more preferably 30% to 85%. In addition, the imidization rate is expressed as a percentage of the ratio of the number of imide ring structures to the total number of amic acid structures and the number of imide ring structures of the polyimide.

[0117] The dehydration ring-closure of polyamic acid is preferably carried out by the following method: dissolving polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and heating as needed. In the method, as a dehydrating agent, for example, anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. Relative to 1 mol of the amic acid structure of polyamic acid, the amount of the dehydrating agent used is preferably set to 0.01 mol to 20 mol. As a dehydration ring-closure catalyst, for example, tertiary amines such as pyridine, trimethylpyridine, dimethylpyridine, and triethylamine can be used. Relative to 1 mol of the dehydrating agent used, the amount of the dehydration ring-closure catalyst used is preferably set to 0.01 mol to 10 mol.

[0118] As the organic solvent used in the dehydration ring-closure reaction, the organic solvent exemplified as the organic solvent used in the synthesis of polyamic acid can be cited. The reaction temperature of the dehydration ring-closure reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 hour to 120 hours. In addition, the reaction solution containing polyimide can be directly used in the preparation of a liquid crystal alignment agent. In addition, polyimide can also be separated from the reaction solution, and the separated polyimide can be used in the preparation of a liquid crystal alignment agent. Polyimide can also be obtained by dehydration ring-closure of polyamic acid esters.

[0119] <Second polymer>

[0120] The second polymer contains a structural unit (II) derived from a diamine having a partial structure represented by the formula (2) (hereinafter also referred to as a "second specific diamine"). In the formula (2), D 2 Specific examples and preferred examples of the monovalent organic group having 5 or more carbon atoms represented by include the following: 1 The specific examples and preferred examples shown in the description are the same as those in the above description.

[0121] When d is 1, R 6 or R 7 For "-C(R 11 )(R 12 )-”, R 11 or R 12 The monovalent hydrocarbon group represented by is preferably an alkyl group having 1 to 3 carbon atoms. 11 or R 12 Examples of the substituent represented by R include an alkoxy group having 1 to 3 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a primary amino group, a cyano group, a nitro group, a hydroxyl group, and a carboxyl group. 11 and R 12 It is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a halogen atom or a hydroxyl group, and more preferably a hydrogen atom.

[0122] R 6 or R 7The divalent alicyclic group represented is a group formed by removing two hydrogen atoms from the ring part of a substituted or unsubstituted aliphatic ring. Examples of the aliphatic ring include saturated or unsaturated hydrocarbon rings having 3 to 12 carbon atoms. Among these, a cyclopentane ring or a cyclohexane ring is preferred.

[0123] R 6 or R 7 The divalent aromatic ring group represented is a group formed by removing two hydrogen atoms from the ring part of a substituted or unsubstituted aromatic ring. The aromatic ring is preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocyclic ring. Specific examples of these include, as aromatic hydrocarbon rings, benzene rings, naphthalene rings, anthracene rings, etc.; as nitrogen-containing aromatic heterocyclic rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, triazine rings, imidazole rings, benzimidazole rings, carbazole rings, etc.

[0124] In R 6 or R 7 When the alkyl group is a divalent alicyclic group or an aromatic ring group and a substituent is bonded to the ring portion, examples of the substituent include an alkyl group having 1 to 3 carbon atoms and a carbon atom having the same carbon atom as R. 11 or R 12 The substituent represented by is the same as the group exemplified in the above. 6 The bond (*) and R 7 The bond (*) of may be a bond to any one of the two primary amino groups of the second specific diamine.

[0125] As d is 2, R 6 is ">C(R 10 )-* 1 " (i.e., a group represented by the following formula (6)), a trivalent alicyclic group, or a trivalent aromatic ring group 6 Specific examples include "-C(R 11 )(R 12 )-"Remove R 12 A group formed by removing one hydrogen atom from a ring portion of a divalent alicyclic group or a divalent aromatic ring group. 7 For "-C(R 11 )(R 12 )-”, a divalent alicyclic group or a divalent aromatic ring group 7 Specific examples of include the same groups as the specific examples when d is 1.

[0126] [Chemistry 13]

[0127]

[0128] (In formula (6), R 10 is a hydrogen atom, a monovalent hydrocarbon group or a substituent. "*1 " indicates a bond on the nitrogen side. "*" indicates a bond)

[0129] In the expression R 6 and R 7 Combined with R 6 and R 7 In the case of a monocyclic or condensed heterocyclic structure formed by the nitrogen atom bonded thereto, the heterocyclic structure is preferably a nitrogen-containing aromatic heterocyclic structure. Specific examples thereof include: 6 or R 7 In the description of a divalent aromatic ring group, the ring structure exemplified as the nitrogen-containing aromatic heterocycle may be included.

[0130] R 8 is a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms. When the partial structure represented by the formula (2) is condensed with other groups in the same molecule by heating during film formation to form a nitrogen-containing aromatic heterocyclic structure containing the nitrogen atom in the formula (2) in the ring skeleton, R is preferably 0.05 in terms of reducing steric hindrance and facilitating the formation of a ring structure. 8 It is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and still more preferably a hydrogen atom. In addition, from the viewpoint of further improving the basicity after ring formation by heating during film formation and improving the reliability with respect to the electrical characteristics of the liquid crystal element, R 8 An alkyl group having 1 to 3 carbon atoms is preferred.

[0131] When b is 1, R 6 and R 7 At least one of R is preferably a group different from the aromatic ring group. 6 and R 7 When all of them are aromatic ring groups, the basicity of the partial structure represented by the formula (2) decreases, and the effect of improving the reliability of the electrical characteristics of the liquid crystal element tends to decrease. Specifically, from the perspective of sufficiently improving the effect of improving the reliability of the electrical characteristics of the liquid crystal element, R 6 and R 7 Preferably, when d is 1, R 6 and R 7 At least one of them is "-C(R 11 )(R 12 )-", or R 6 and R 7 Combined with R 6 and R 7 In addition, when d is 2, R 6 is ">C(R 10 )-*1 ”, R 7 For "-C(R 11 )(R 12 )-", or satisfies both of these, or indicates R 6 and R 7 Combined with R 6 and R 7 The nitrogen atoms to which the ring is bonded together form a monocyclic or condensed heterocyclic structure.

[0132] The second polymer may have at least a part of the partial structure represented by the formula (2) in the main chain of the polymer, and may also have the partial structure represented by the formula (2) in the side chain. In addition, in the second polymer, the nitrogen atom in the formula (2) may constitute a part of the main chain of the polymer, and may also be contained in the side chain. From the viewpoint of further improving the reliability with respect to the electrical characteristics of the liquid crystal element, it is preferred that the nitrogen atom in the formula (2) constitutes a part of the main chain of the polymer, or is bonded to a carbon atom constituting a part of the main chain of the polymer.

[0133] By formulating the second polymer, good liquid crystal orientation is maintained in the liquid crystal element, and the effect of improving the reliability relative to the electrical characteristics of the liquid crystal element is further improved. From this point of view, the structural unit (II) is preferably selected from the group consisting of the structural unit (II-1) and the structural unit (II-2) shown below.

[0134] Structural unit (II-1): derived from a compound having a nitrogen atom in the formula (2) bonded with "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 "The diamine structural unit of the partial structure

[0135] Structural unit (II-2): A structural unit derived from a diamine having a nitrogen-containing aromatic heterocycle or having a partial structure that forms a nitrogen-containing aromatic heterocycle upon heating

[0136] Hereinafter, each structural unit will be described.

[0137] Structural unit (II-1)

[0138] By having a structural unit (II-1) in the second polymer, a site with high basicity is introduced into the polymer. Thus, the improvement effect of reliability relative to the electrical characteristics of the liquid crystal element can be further improved. In addition, the partial structure represented by the formula (2) easily shows cross-linking, which can help improve the mechanical properties of the liquid crystal alignment film, and is preferred in terms of the above aspect. The diamine providing the structural unit (II-1) is preferably a partial structure represented by the following formula (2A).

[0139] [Chemistry 14]

[0140]

[0141] (In formula (2A), D 2A is a monovalent thermally detachable group. d is 1 or 2. When d is 1, R 6 and R 7 Independently of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group. 6 and R 7 At least one of them is "-C(R 11 )(R 12 )-". In the case where d is 2, R 6 and R 7 Medium R 6 is ">C(R 10 )-* 1 " represents a trivalent group, a trivalent alicyclic group or a trivalent aromatic ring group (wherein "* 1 ” indicates the bond on the nitrogen side), R 7 For "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group. 6 When R is a trivalent alicyclic group or a trivalent aromatic ring group, 7 For "-C(R 11 )(R 12 )-”, in R 7 When R is a divalent alicyclic group or a divalent aromatic ring group, 6 is ">C(R 10 )-* 1 " represents a trivalent radical. 11 and R 12 R is independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a substituent. 8 is a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms. a is 1 or 2. b is 0 or 1. c is 0 or 1. Where a+b+c=2 is satisfied. When b is 0, R 6 For "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 ". " " indicates a bond)

[0142] Specific examples of the partial structure represented by the formula (2A) include partial structures represented by the following formulae (2A-1) to (2A-8), respectively.

[0143] [Chemistry 15]

[0144]

[0145] (In formula (2A-1) to formula (2A-8), "*" represents a bonding bond)

[0146] About R when b is 1 6 and R 7 From the viewpoint of further improving the reliability of the electrical characteristics of the liquid crystal element by introducing the alkaline site, when d is 1, R 6 and R 7 All are "-C(R 11 )(R 12 )-", when d is 2, preferably R 6 is ">C(R 10 )-* 1 " and R 7 For "-C(R 11 )(R 12 )-". Specifically, the partial structure represented by the formula (2A) is preferably the formula (2A-3) to the formula (2A-5) among the formulas (2A-1) to (2A-5), and more preferably the formula (2A-3).

[0147] Specific examples of preferred diamines for providing structural unit (II-1) include compounds represented by the following formula (4) in that a liquid crystal element having excellent reliability and further excellent mechanical properties can be obtained.

[0148] [Chemistry 16]

[0149]

[0150] (In formula (4), Ar 1 and Ar 2 are independently a divalent aromatic ring group. 1 and X 2 Each of them is independently a divalent chain hydrocarbon group or a divalent group in which a part of the methylene groups in the chain hydrocarbon group is substituted with -O-, -S-, -CO- or -COO-. 1 and Y 2 are independently a group having a "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 "The base of the partial structure. 3is a divalent organic group. r is an integer from 0 to 3. When r is 2 or 3, the multiple X 3 , Y 2 Same or different from each other)

[0151] In the formula (4), Ar 1 or Ar 2 The divalent aromatic ring group represented by can be exemplified as 6 or R 7 In the case of a divalent aromatic ring group, the groups are the same as those exemplified in the specific examples. 1 or Ar 2 It is preferably an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and among them, it is preferably a group having a benzene ring, a naphthalene ring or a pyridine ring. 1 or Ar 2 The ring part may have a substituent. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms and a 11 or R 12 In the case of a substituent, it is the same group as exemplified.

[0152] As X 1 or X 2 The divalent chain hydrocarbon group represented by may be an alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 1 to 20 carbon atoms, etc. Among these, an alkanediyl group having 1 to 10 carbon atoms is preferred, and a linear alkanediyl group having 1 to 5 carbon atoms is more preferred. 1 or X 2 In the case of a divalent group in which a part of the methylene groups in the chain hydrocarbon group is substituted with -O-, -S-, -CO- or -COO-, the chain hydrocarbon group is preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably a linear alkanediyl group having 2 to 6 carbon atoms.

[0153] As X 3 The divalent organic group represented by the present invention includes a divalent chain hydrocarbon group having 1 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent group in which a part of the methylene groups in the chain hydrocarbon group having 2 to 20 carbon atoms are substituted with -O-, -S-, -CO- or -COO-, and a hydrocarbon group or a group in which a part of the hydrogen atoms of the divalent group are substituted with a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, a carboxyl group, and the like.

[0154] Y 1 or Y 2 Preferably, it has a partial structure represented by the above formula (2A), and specifically, it includes groups having partial structures represented by the above formulas (2A-1) to (2A-8). 1 or Y 2Preferably, the nitrogen atom in the formula (2) forms part of the main chain, or the nitrogen atom in the formula (2) is bonded to a carbon atom forming part of the main chain (for example, the partial structures represented by the formulas (2A-1) to (2A-7)). 1 or Y 2 With this structure, the reliability of the liquid crystal element can be further improved.

[0155] r is preferably 0-2, more preferably 0 or 1.

[0156] Structural unit (II-2)

[0157] The second polymer has a structural unit (II-2), which can improve the reliability of the electrical characteristics of the liquid crystal element and make the liquid crystal orientation good, which is preferred in terms of the above aspects. As the nitrogen-containing aromatic heterocyclic ring possessed by the diamine providing the structural unit (II-2), there can be listed: pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring, imidazole ring, benzimidazole ring, carbazole ring, etc., among which, imidazole ring, pyridine ring, pyrimidine ring, benzimidazole ring or carbazole ring is preferred. The nitrogen-containing aromatic heterocyclic ring formed by heating is preferably a benzimidazole ring.

[0158] Specific examples of the diamine providing the structural unit (II-2) include: a diamine having a partial structure in which a nitrogen-containing aromatic heterocyclic group is bonded to the nitrogen atom in the formula (2) (hereinafter also referred to as a "first heterocyclic diamine"); a diamine having R in the formula (2) 6 and R 7 Combined with R 6 and R 7 A diamine having a nitrogen-containing aromatic heterocyclic structure of a monocyclic or condensed ring type composed of the nitrogen atom bonded thereto (hereinafter also referred to as the "second heterocyclic diamine"); a diamine having a partial structure capable of forming a nitrogen-containing aromatic heterocyclic structure containing the nitrogen atom in the formula (2) in the ring skeleton by heating (hereinafter also referred to as the "third heterocyclic diamine");

[0159] Examples of the first heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-1) to (2B-6). Examples of the second heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-7) to (2B-10). Examples of the third heterocyclic diamine include compounds having partial structures represented by the following formulae (2B-11) to (2B-14).

[0160] [Chemistry 17]

[0161]

[0162] (In formula (2B-1) to formula (2B-14), "*" represents a bonding bond)

[0163] As a specific example of the 2nd specific diamine, the compound etc. represented by following formula (2-1) - formula (2-30) are mentioned.

[0164] [Chemistry 18]

[0165]

[0166] [Chemistry 19]

[0167]

[0168] [Chemistry 20]

[0169]

[0170] [Chemistry 21]

[0171]

[0172] In terms of high contribution to the reliability of the electrical characteristics of the liquid crystal element and the effect of the liquid crystal orientation, the second specific diamine preferably includes a compound having "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 " is a diamine having a partial structure, more preferably a diamine represented by the formula (4). In addition, in the formulas (2-1) to (2-30), the compounds represented by the formulas (2-1) to (2-10) and (2-29) are diamines that provide structural units (II-1). In addition, the compounds represented by the formulas (2-11) to (2-23) and (2-30) are diamines that provide structural units (II-2).

[0173] In order to obtain a liquid crystal element having high reliability and mechanical properties with respect to electrical properties of the liquid crystal element and showing good liquid crystal orientation, the second polymer preferably contains the following structural unit as structural unit (II), wherein the structural unit is derived from a structure having "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 ". Among them, the diamine having the following partial structure is particularly preferred: a diamine having a partial structure in which "-C(R 11 )(R 12 )-" or ">C(R10 )-* 1 ", and the nitrogen atom in the formula (2) constitutes a part of the main chain, or the nitrogen atom in the formula (2) is bonded to a carbon atom constituting a part of the main chain.

[0174] In the second polymer, from the viewpoint of fully obtaining the effect of improving the reliability with respect to the electrical characteristics of the liquid crystal element, the content ratio of the structural unit (II) relative to the total amount of the structural unit derived from the diamine compound possessed by the second polymer is preferably 2 mol% or more, more preferably 5 mol% or more, and further preferably 10 mol% or more. In addition, when a structural unit different from the structural unit (II) is introduced into the polymer to adjust various characteristics such as voltage holding ratio or liquid crystal orientation, the content ratio of the structural unit (II) in the second polymer is, for example, 95 mol% or less relative to the total amount of the structural unit derived from the diamine compound possessed by the second polymer.

[0175] In addition, the synthesis method of the second polymer is also not particularly limited. The second polymer can be obtained by a method including a process of polycondensing a tetracarboxylic acid derivative with a diamine compound. For example, in the case of obtaining polyamic acid as the second polymer, it can be obtained by reacting a tetracarboxylic dianhydride exemplified as a tetracarboxylic dianhydride that can be used in the synthesis of the first polymer with a diamine compound containing a second specific diamine. At this time, as a diamine compound, only the second specific diamine can be used, or a diamine compound different from the second specific diamine (hereinafter, also referred to as "the second other diamine") can be used in combination. As the second other diamine, the diamines identical to the first specific diamine and the first other diamine exemplified in the description of the first polymer can be cited. For details of the synthesis method of the second polymer, the description of the first polymer is applied.

[0176] Among them, from the viewpoint of promoting the phase separation of the first polymer and the second polymer in the liquid crystal alignment film, the content ratio of the structural unit (I) in the second polymer is preferably equal to or less than the content ratio of the structural unit (I) in the first polymer. Specifically, the content ratio of the structural unit (I) in the second polymer is preferably 20 mol% or less, more preferably 15 mol% or less, further preferably 10 mol% or less, and further more preferably 5 mol% or less, relative to the total amount of the structural unit derived from the diamine compound possessed by the second polymer.

[0177] From the viewpoint of further enhancing the effect of improving the electrical properties, the second other diamine preferably includes a diamine selected from the group consisting of diamines capable of converting * 3 -CO-NH-* 3 or* 3 -NH-CO-NH-* 3 The diamine introduced into the polymer backbone (wherein, “*3 " represents a bond with an aliphatic hydrocarbon group or an aromatic hydrocarbon group), capable of converting *-Ar 5 -N(R 13 )-Ar 6 - The partial structure represented by * is introduced into the diamine of the polymer main chain (wherein Ar 5 and Ar 6 are independently divalent aromatic ring groups, R 13 is a hydrogen atom or a monovalent hydrocarbon group. "*" represents a bond), and at least one of the group consisting of diamines capable of introducing a nitrogen-containing aromatic condensed ring structure into the polymer main chain (hereinafter also referred to as "diamine (D2)").

[0178] As a way to 3 -CO-NH-* 3 or* 3 -NH-CO-NH-* 3 Examples of the diamine introduced into the main chain of the polymer include compounds represented by the following formula.

[0179] [Chemistry 22]

[0180]

[0181] As a 5 -N(R 13 )-Ar 6 Examples of the diamine in which the partial structure represented by -* is introduced into the polymer main chain include compounds represented by the following formulas.

[0182] [Chemistry 23]

[0183]

[0184] Examples of the diamine capable of introducing a nitrogen-containing aromatic fused ring structure into the polymer main chain include compounds represented by the following formula.

[0185] [Chemistry 24]

[0186]

[0187] When a diamine (D2) is used in the synthesis of the second polymer, the content ratio of the structural unit derived from the diamine (D2) in the second polymer is preferably 2 mol% or more, more preferably 5 mol% or more, relative to the total amount of the structural unit derived from the diamine compound in the second polymer. In addition, the content ratio of the structural unit derived from the diamine (D2) in the second polymer is preferably 80 mol% or less, more preferably 70 mol% or less, relative to the total amount of the structural unit derived from the diamine compound in the second polymer.

[0188] From the viewpoint of being able to fully demonstrate the effect of improving the liquid crystal alignment brought about by the formulation of the first polymer and the effect of improving the reliability with respect to electrical characteristics brought about by the formulation of the second polymer, and obtaining a liquid crystal alignment film having excellent mechanical characteristics, D in the formula (1) is 1 And D in the formula (2) 2 Preferably, it is a monovalent thermally detachable group. 1 And D in the formula (2) 2 When D is a monovalent thermally detachable group, it is believed that the separation of polymer chains can be suppressed, thereby improving the mechanical properties. From the perspective of reducing the amount of the structure detached by heat in the film and suppressing the reduction in the mechanical properties or performance of the film, D in the formula (1) is 1 And D in the formula (2) 2 A Boc group is preferred.

[0189] When a solution having a concentration of 10% by mass is prepared, the solution viscosity of the first polymer and the second polymer is preferably 10mPa·s to 800mPa·s, and more preferably 15mPa·s to 500mPa·s. In addition, the solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a polymer solution having a concentration of 10% by mass prepared using a good solvent (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) for the first polymer and the second polymer.

[0190] The first polymer and the second polymer preferably have a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 7 or less, more preferably 5 or less.

[0191] Relative to the total amount of 100 parts by mass of the first polymer and the second polymer contained in the liquid crystal alignment agent, the content ratio of the first polymer in the liquid crystal alignment agent is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more. In addition, relative to the total amount of 100 parts by mass of the first polymer and the second polymer contained in the liquid crystal alignment agent, the content ratio of the first polymer is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and further preferably 50 parts by mass or less. In other words, relative to the total amount of 100 parts by mass of the first polymer and the second polymer contained in the liquid crystal alignment agent, the content ratio of the second polymer is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and further preferably 50 parts by mass or more. In addition, relative to the total amount of 100 parts by mass of the first polymer and the second polymer contained in the liquid crystal alignment agent, the content ratio of the second polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and further preferably 85 parts by mass or less. By setting the content ratio of the first polymer and the second polymer in the liquid crystal alignment agent to the range, a liquid crystal element having a good balance between liquid crystal orientation and electrical properties can be obtained.

[0192] From the viewpoint of obtaining a liquid crystal element with a good balance between liquid crystal orientation and electrical properties, the total content of the first polymer and the second polymer in the liquid crystal alignment agent is preferably 50 mass % or more, more preferably 60 mass % or more, and even more preferably 70 mass % or more, relative to the total amount of solid components contained in the liquid crystal alignment agent (i.e., the total mass of components other than the solvent of the liquid crystal alignment agent).

[0193] <Other ingredients>

[0194] As other components mix|blended in the liquid crystal aligning agent of this indication, the polymer different from a 1st polymer and a 2nd polymer (it is also called "other polymer" hereinafter), a crosslinking agent, etc. are mentioned, for example.

[0195] Other polymers

[0196] As long as other polymers are polymers that do not have any of the structural units (I) and the structural units (II), their main skeletons are not particularly limited. As other polymers, for example, polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamide-imide, polybenzoxazole precursor, polybenzoxazole, cellulose derivatives, polyacetal, addition polymers, etc. can be cited. From the perspective of obtaining a liquid crystal element with high reliability of various performances such as electrical properties or liquid crystal orientation, other polymers are preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester, polyimide, polyurea, polyamide-imide, polyorganosiloxane and addition polymers, and more preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane and addition polymers.

[0197] The content of other polymers in the liquid crystal aligning agent of the present disclosure is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less, relative to the total amount of the first polymer, the second polymer, and other polymers.

[0198] Cross-linking agent

[0199] Examples of the crosslinking agent include compounds having at least one crosslinking group selected from the group consisting of a group having a polymerizable carbon-carbon bond, a cyclic ether group, a cyclic thioether group, an isocyanate group, a protected isocyanate group, a hydroxymethyl group, a protected hydroxymethyl group, a hydroxyalkylamide group, a protected hydroxyalkylamide group, a cyclic carbonate group, a group "-CR 31 =CR 32 -R 33 -”(where R 31 It is a monovalent organic group that is released by reaction with an amino group. 32 is a hydrogen atom or an alkyl group, R 33 is an electron-withdrawing group), a silanol group, an amino group, a protected amino group and an alkoxysilyl group.

[0200] Among the crosslinking groups, groups having polymerizable carbon-carbon bonds include (meth)acryloyl, maleimide, alkenyl, vinylphenyl, vinyl ether, 3-methylenetetrahydrofuran-2(3H)-one-5-yl, etc. As the crosslinking agent, the compound having a functional group capable of reacting with an amino group or a carboxyl group can be preferably used, and among them, the compound having a total of two or more selected from the group consisting of a cyclic ether group, a hydroxyalkylamide group, a protected hydroxyalkylamide group, a hydroxymethyl group, a protected hydroxymethyl group, a protected isocyanate group, an amino group, a protected amino group, and an alkoxysilyl group in one molecule can be preferably used.

[0201] From the viewpoint of improving the liquid crystal orientation, voltage holding characteristics and film strength of the liquid crystal element in a well-balanced manner, the number of crosslinking groups in one molecule of the crosslinking agent is preferably 2 to 12, more preferably 2 to 10. From the viewpoint of ensuring good storage stability, the molecular weight of the crosslinking agent is preferably 2,000 or less, more preferably 1,000 or less, and further preferably 800 or less.

[0202] Specific examples of the crosslinking agent include compounds having a cyclic ether group, such as N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N-diglycidyl-aminomethylcyclohexane, N,N-diglycidyl-cyclohexylamine, cyclic siloxanes having two or more glycidyl groups, and epoxidation reaction products of pentaerythritol tetraallyl ether and hydrogen peroxide.

[0203] Examples of the compound having a hydroxyalkylamide group or a protected hydroxyalkylamide group include compounds represented by the following formulas (c-1) to (c-3);

[0204] Examples of the compound having a hydroxymethyl group or a protected hydroxymethyl group include compounds represented by the following formulae (c-4) to (c-9);

[0205] Examples of the compound having a protected isocyanate group include compounds represented by the following formulae (c-10) to (c-14);

[0206] Examples of the compound having an amino group or a protected amino group include compounds represented by the following formula (c-15) to (c-18);

[0207] Examples of the compound having an alkoxysilyl group include glycidyloxypropyltrimethoxysilane, glycidyloxypropyltriethoxysilane, and 3-aminopropyltrimethoxysilane.

[0208] [Chemistry 25]

[0209]

[0210] [Chemistry 26]

[0211]

[0212] (In formula (c-8), Ac is an acetyl group)

[0213] [Chemistry 27]

[0214]

[0215] (In formula (c-10) and formula (c-11), R 34 is tert-butoxy)

[0216] [Chemistry 28]

[0217]

[0218] In the case of deploying a crosslinking agent in the liquid crystal alignment agent of the present disclosure, from the viewpoint of making the liquid crystal orientation and voltage holding characteristics better, the content ratio of the crosslinking agent is preferably 0.5 parts by mass or more relative to the total amount of the polymer components contained in the liquid crystal alignment agent (i.e., the total amount of the first polymer, the second polymer and other polymers) 100 parts by mass. Relative to the total amount of 100 parts by mass of the polymer component, the content ratio of the crosslinking agent is more preferably 1 part by mass or more, and more preferably 2 parts by mass or more. In addition, from the viewpoint of ensuring the liquid crystal orientation and voltage holding characteristics of the liquid crystal element and the storage stability of the liquid crystal alignment agent, the content ratio of the crosslinking agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less relative to the total amount of 100 parts by mass of the polymer component.

[0219] Solvent

[0220] The liquid crystal alignment agent disclosed in the present invention is prepared in the form of a liquid composition, and the liquid composition is prepared by dispersing or dissolving the first polymer, the second polymer, and other components used as required in an appropriate solvent.

[0221] As the solvent, an organic solvent can be preferably used. Specific examples thereof include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 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, 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 (propylene glycol monomethyl ether, PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (propylene glycol monomethyl ether acetate, PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. As the solvent, one kind may be used alone or two or more kinds may be used in mixture.

[0222] As other components contained in the liquid crystal alignment agent, in addition to the above, for example, antioxidants, metal chelate compounds, hardening accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The blending ratio of other components can be appropriately selected according to each compound within the range that does not impair the effects of the present disclosure.

[0223] The solid content concentration of the liquid crystal alignment agent (the ratio of the total mass of the components of the liquid crystal alignment agent other than the solvent to the total mass of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal alignment agent is preferably in the range of 1% by mass to 10% by mass. If the solid content concentration is 1% by mass or more, the film thickness of the coating can be fully ensured, and a liquid crystal alignment film showing better liquid crystal orientation can be obtained, which is preferred in this respect. On the other hand, if the solid content concentration is 10% by mass or less, there is a tendency as follows: the coating can be set to a moderate thickness, and a liquid crystal alignment film showing good liquid crystal orientation can be easily obtained. In addition, the viscosity of the liquid crystal alignment agent becomes moderate, which can make the coating property good.

[0224] 《Liquid crystal alignment film and its manufacturing method》

[0225] The liquid crystal alignment film of the present disclosure can be formed by the liquid crystal alignment agent prepared in the above manner. The liquid crystal alignment film can be manufactured by a method including the following film forming process. In addition, the liquid crystal alignment film of the present disclosure can also be subjected to a liquid crystal alignment treatment on the organic film obtained by the film forming process by the following alignment treatment process, thereby imparting liquid crystal alignment ability.

[0226] · Film forming process

[0227] When manufacturing a liquid crystal alignment film, first, a liquid crystal alignment agent is coated on a substrate, and preferably the coated surface is heated to form a coating film on the substrate. As the substrate, for example, a transparent substrate containing the following materials can be used: glass such as float glass and soda glass; plastics such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, poly (alicyclic olefin) and the like.

[0228] The method for applying the liquid crystal alignment agent to the substrate is not particularly limited. The liquid crystal alignment agent can be applied to the substrate by, for example, spin coating, printing (e.g., offset printing, flexographic printing, etc.), inkjet, slit coating, rod coating, extrusion die, direct gravure coater, chamber doctor coater, offset gravure coater, impregnation coater, MB coater, etc.

[0229] After applying the liquid crystal alignment agent, it is preferred to perform preheating (prebaking) for the purpose of preventing the applied liquid crystal alignment agent from sagging. The prebaking temperature is preferably 30°C to 200°C, and the prebaking time is preferably 0.25 minutes to 10 minutes. Afterwards, the solvent is completely removed, and a calcination (post-baking) process is performed as needed for the purpose of thermal imidization of the amide acid structure present in the polymer. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 280°C, and more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001μm to 1μm.

[0230] Orientation treatment process

[0231] In the orientation treatment process, it is preferred to apply the liquid crystal orientation agent to the substrate, and after the application, it is preferably subjected to a heat treatment, and then a friction treatment or a light irradiation treatment is performed to impart liquid crystal orientation ability. In the friction treatment, a roller wound with a cloth containing fibers such as nylon, rayon, and cotton is used to rub the coating formed on the substrate in a certain direction, thereby imparting liquid crystal orientation ability to the coating. In the light orientation treatment, the coating formed on the substrate is irradiated with light to impart liquid crystal orientation ability to the coating.

[0232] In the photo-alignment treatment, light irradiation can be carried out by the following methods, etc.: a method of irradiating the coating after the post-baking process, a method of irradiating the coating after the pre-baking process and before the post-baking process, and a method of irradiating the coating during the heating process of the coating in at least any one of the pre-baking process and the post-baking process. As radiation irradiated to the coating, for example, ultraviolet rays and visible light containing light with a wavelength of 150nm to 800nm ​​can be used. Preferably, ultraviolet rays containing light with a wavelength of 200nm to 400nm are used. In the case where the radiation is polarized, it can be linearly polarized or partially polarized. In the case where the radiation used is linearly polarized or partially polarized, the irradiation can be carried out from a direction perpendicular to the substrate surface, from an inclined direction, or in combination of these directions. The irradiation direction in the case of non-polarized radiation is set to an inclined direction.

[0233] Examples of the light source include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and an excimer laser. The radiation dose is preferably 400 J / m 2 ~50,000J / m 2 , more preferably 1,000 J / m 2 ~20,000J / m 2 After irradiation with light for imparting alignment ability, the substrate surface may be cleaned using, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0234] Liquid Crystal Element

[0235] The liquid crystal element disclosed herein includes a liquid crystal alignment film formed using the liquid crystal alignment agent described in the description. The driving mode of the liquid crystal in the liquid crystal element is not particularly limited, for example, it can be applied to twisted nematic (Twisted Nematic, TN) type, super twisted nematic (Super Twisted Nematic, STN) type, vertical alignment (Vertical Alignment, VA) type (including vertical alignment-multi-domain vertical alignment (Vertical Alignment-Multi-domain Vertical Alignment, VA-MVA) type, vertical alignment-patterned vertical alignment (Vertical Alignment-PatternedVertical Alignment, VA-PVA) type, etc.), in-plane switching (In Plane Switching, IPS) type, fringe field switching (Fringe Field Switching, FFS) type, optically compensated bending (Optically Compensated Bend, OCB) type, polymer stabilized alignment (Polymer Sustained Alignment, PSA) type and other modes. The liquid crystal element can be manufactured, for example, by a method including the coating formation process and the orientation treatment process, and the following unit construction process.

[0236] The substrate used in the coating film forming process is different depending on the desired operating mode. For example, in the case of manufacturing a TN type, STN type or VA type liquid crystal element, two substrates provided with a patterned transparent conductive film are used. In the case of manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with electrodes patterned into a comb-shaped shape and an opposing substrate without electrodes are used. As a transparent conductive film, a NESA film (registered trademark of PPG Company, USA) containing tin oxide (SnO2), an indium tin oxide (Indium Tin Oxide, ITO) film containing indium oxide-tin oxide (In2O3-SnO2), etc. can be used.

[0237] In addition, in the case of manufacturing the liquid crystal cell of TN type, STN type, IPS type or FFS type, the process (orientation treatment) of giving liquid crystal orientation ability to the film obtained by the film forming process is implemented. Thus, the orientation ability of liquid crystal molecules is given to the film and becomes a liquid crystal alignment film. On the other hand, in the case of manufacturing the liquid crystal cell of vertical orientation (VA) type, the film obtained by the film forming process can be directly used as a liquid crystal alignment film. In addition, in order to further improve the liquid crystal orientation ability, the film can also be subjected to orientation treatment. The preferred liquid crystal alignment film for the liquid crystal cell of vertical orientation type is also preferred for the liquid crystal cell of PSA type.

[0238] Unit construction process

[0239] Prepare two substrates formed with liquid crystal alignment films in the manner described above, and manufacture a liquid crystal unit in a manner that liquid crystals are arranged adjacent to the liquid crystal alignment films between the two substrates. When manufacturing a liquid crystal unit, for example, the following methods can be cited: two substrates are arranged opposite to each other with a gap in a manner that the liquid crystal alignment films face each other, the peripheral portions of the two substrates are bonded together using a sealant, and a method of injecting and filling liquid crystals into the cell gap surrounded by the substrate surface and the sealant and sealing the injection hole, a method using a liquid crystal drop (One Drop Fill, ODF) method, etc. As a sealant, for example, an epoxy resin containing a hardener and alumina balls as a spacer can be used. As liquid crystals, nematic liquid crystals and disc-shaped liquid crystals can be cited, among which nematic liquid crystals are preferred. In the PSA mode, after constructing a liquid crystal unit, the liquid crystal unit is subjected to light irradiation treatment while a voltage is applied between the conductive films of a pair of substrates.

[0240] The PSA type liquid crystal element can be produced by a method including the following steps.

[0241] A step of applying the liquid crystal aligning agent of the present disclosure onto the conductive film of each of a pair of substrates having a conductive film to form a coating film.

[0242] A step of constructing a liquid crystal cell by arranging a pair of substrates coated with a liquid crystal aligning agent so that the coated films face each other with a liquid crystal layer interposed therebetween.

[0243] A step of irradiating the liquid crystal cell with light while a voltage is applied between the conductive films.

[0244] Specifically, first, a liquid crystal and a photopolymerizable monomer are injected or dropped between a pair of substrates having a conductive film, and a liquid crystal cell is constructed in the same manner as in the above steps 1 to 3 except for the above aspects. As the photopolymerizable monomer injected or dropped with the liquid crystal, a conventionally known compound can be used. Preferably, a multifunctional (meth)acrylic monomer is used.

[0245] In the manufacture of a PSA type liquid crystal element, after constructing a liquid crystal unit, the liquid crystal unit is irradiated with light while a voltage is applied between the conductive films of a pair of substrates. The applied voltage can be set to, for example, a direct current or alternating current of 5V to 50V. As the irradiated light, for example, ultraviolet rays and visible rays containing wavelengths of 150nm to 800nm ​​can be used. Among these, ultraviolet rays containing wavelengths of 300nm to 400nm are preferred. As the light source of the irradiated light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. As the irradiation amount of light, 1,000J / m 2 ~200,000J / m2 , more preferably 1,000 J / m 2 ~100,000J / m 2 .

[0246] For each mode of the liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as needed to prepare a liquid crystal element. Examples of the polarizing plate include a polarizing plate obtained by sandwiching a polarizing film called "H film" in which polyvinyl alcohol is stretched and oriented and iodine is absorbed by cellulose acetate protective films, or a polarizing plate including the H film itself.

[0247] As liquid crystal, any of positive type and negative type can be used. When negative type liquid crystal is used in IPS type and FFS type liquid crystal elements, the transmission loss of the upper part of the electrode can be reduced, and the contrast can be improved, which is preferred in terms of the above aspects. As liquid crystal, nematic liquid crystal and smectic liquid crystal can be listed, among which nematic liquid crystal is preferred.

[0248] The liquid crystal element disclosed in the present invention can be effectively applied to various purposes. Specifically, for example, it can be used as various display devices such as clocks, portable game consoles, word processors, notebook personal computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smart phones, various monitors, liquid crystal televisions, information displays, or dimming devices, phase difference films, etc.

[0249] The present disclosure described above provides the following means.

[0250] [Means 1] A liquid crystal alignment agent, comprising a first polymer and a second polymer as imide polymers selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, wherein the first polymer contains a structural unit (I) derived from a diamine having a partial structure represented by the formula (1) and a structural unit (T) derived from a compound represented by the formula (3), and the content ratio of the structural unit (T) relative to the total amount of structural units derived from tetracarboxylic acid derivatives possessed by the first polymer is 75 mol% or more, and the second polymer is a polymer different from the first polymer and contains a structural unit (II) derived from a diamine having a partial structure represented by the formula (2).

[0251] [Means 2] The liquid crystal alignment agent according to [Means 1], wherein D in the formula (1) 1 And D in the formula (2) 2 It is a monovalent thermally detached group.

[0252] [Means 3] The liquid crystal alignment agent according to [Means 1] or [Means 2], wherein R in the formula (1) 4 and R 5 One or both of them have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group and R in the formula (1) 1 or R 2 Bond.

[0253] [Means 4] The liquid crystal alignment agent according to any one of [Means 1] to [Means 3], wherein the first polymer has a partial structure represented by the formula (1) in the main chain.

[0254] [Means 5] The liquid crystal alignment agent according to any one of [Means 1] to [Means 4], wherein the first polymer has structural units derived from four or more diamine compounds including the structural unit (I).

[0255] [Means 6] A liquid crystal alignment agent according to any one of [Means 1] to [Means 5], wherein the nitrogen atom in the formula (2) constitutes a part of the main chain of the second polymer, or the nitrogen atom in the formula (2) is bonded to a carbon atom constituting a part of the main chain of the second polymer.

[0256] [Means 7] A liquid crystal alignment agent according to any one of [Means 1] to [Means 6], wherein the second polymer comprises a structural unit (II-1) derived from a diamine as the structural unit (II), and the diamine has a "-C(R 11 )(R 12 )-" or ">C(R 10 )-* 1 "Part of the structure.

[0257] [Means 8] The liquid crystal aligning agent according to [Means 7], wherein the structural unit (II-1) is a structural unit derived from a diamine represented by the formula (4).

[0258] [Means 9] The liquid crystal aligning agent according to any one of [Means 1] to [Means 8], further comprising a crosslinking agent.

[0259] [Means 10] A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of [Means 1] to [Means 9].

[0260] [Means 11] A liquid crystal element comprising the liquid crystal alignment film according to [Means 10].

[0261] [Example]

[0262] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not to be limitedly interpreted by the following Examples.

[0263] In the following examples, the imidization ratio of the polyimide in the polymer solution was measured by the following method.

[0264] [Imidization ratio of polyimide]

[0265] The polyimide solution was added to pure water, the obtained precipitate was fully dried under reduced pressure at room temperature, and then dissolved in deuterated dimethyl sulfoxide. Hydrogen nuclear magnetic resonance (H-NMR) was performed at room temperature using tetramethylsilane as a reference substance. 1 H-Nuclear Magnetic Resonance, 1 H-NMR) determination. 1 The imidization ratio [%] was determined by using the following formula (1) based on the H-NMR spectrum.

[0266] Imidization rate [%] = (1-(A 1 / (A 2 ×α)))×100···(1)

[0267] (In equation (1), A 1 A is the peak area of ​​the proton origin of the NH group that appears near the chemical shift of 10 ppm. 2 is the peak area of ​​other proton sources. α is the ratio of the number of other protons in the polymer precursor (polyamic acid) to one proton of the NH group)

[0268] In the following examples, the necessary amounts of raw material compounds and polymers were ensured by repeating the synthesis on the synthesis scale shown in the following synthesis examples as necessary. In addition, "parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

[0269] The abbreviations of the compounds are as follows: In addition, hereinafter, the compound represented by the formula (X) may be simply referred to as "compound (X)".

[0270] (Tetracarboxylic dianhydride)

[0271] [Chemistry 29]

[0272]

[0273] (Diamine compound)·First specific diamine

[0274] [Chemistry 30]

[0275]

[0276] ·Second specific diamine

[0277] [Chemistry 31]

[0278]

[0279] Other diamines

[0280] [Chemistry 32]

[0281]

[0282] [Chemistry 33]

[0283]

[0284] [Chemistry 34]

[0285]

[0286] (additive)

[0287] [Chemistry 35]

[0288]

[0289] <Polymer Synthesis>

[0290] 1. Synthesis of polyamic acid

[0291] [Synthesis example 1]

[0292] 100 mol parts of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (compound (b-1)) as a tetracarboxylic dianhydride, 20 mol parts of compound (DA-1) as a diamine compound, 10 mol parts of compound (a-1), 20 mol parts of compound (a-4), and 50 mol parts of compound (a-7) were dissolved in N-methyl-2-pyrrolidone (NMP), and reacted at 40° C. for 6 hours to obtain a solution containing 15% by mass of a polyamic acid (referred to as polymer (PAA-1)).

[0293] [Synthesis Example 2 to Synthesis Example 55]

[0294] The same operation as in Synthesis Example 1 was performed except that the types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as described in Table 1, thereby obtaining polyamic acids (polymers (PAA-2) to (PAA-48) and polymers (PA-1) to (PA-7)). In addition, the numerical values ​​of tetracarboxylic dianhydride (acid dianhydride 1 to acid dianhydride 3) in Table 1 represent the ratio (molar ratio) of each compound relative to 100 parts by mole of the total amount of tetracarboxylic dianhydride used in the synthesis of each polyamic acid. The numerical values ​​of diamine compounds (diamine 1 to diamine 4) represent the ratio (molar ratio) of each compound relative to 100 parts by mole of the total amount of diamine compounds used in the synthesis of each polyamic acid.

[0295] [Table 1]

[0296]

[0297] 2. Synthesis of polyimide

[0298] [Synthesis Example 56]

[0299] The same operation as in Synthesis Example 1 was performed to obtain a solution containing 15% by mass of the polymer (PAA-1). Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was performed at 60° C. for 4 hours. After the dehydration ring-closure reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 15% by mass of a polyimide (hereinafter referred to as polymer (PI-1)) having an imidization rate of about 80%.

[0300] [Synthesis Example 57]

[0301] The same operation as in Synthesis Example 56 was performed except that the amount of pyridine and acetic anhydride added was set to 0.6 times the amount used in Synthesis Example 56, thereby obtaining a solution containing 15% by mass of a polyimide (referred to as polymer (PI-2)) having an imidization rate of approximately 60%.

[0302] [Synthesis Example 58]

[0303] The same operation as in Synthesis Example 4 was performed to obtain a solution containing 15% by mass of a polymer (PAA-4). Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was performed at 60° C. for 4 hours. At this time, the amount of pyridine and acetic anhydride added was adjusted to 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closure reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 15% by mass of a polyimide (referred to as polymer (PI-3)) having an imidization rate of about 60%.

[0304] [Synthesis Example 59]

[0305] The same operation as in Synthesis Example 11 was performed to obtain a solution containing 15% by mass of a polymer (PAA-11). Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was performed at 60° C. for 4 hours. At this time, the amount of pyridine and acetic anhydride added was adjusted to 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closure reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 15% by mass of a polyimide (referred to as polymer (PI-4)) having an imidization rate of about 50%.

[0306] [Synthesis Example 60]

[0307] The same operation as in Synthesis Example 12 was performed to obtain a solution containing 15% by mass of a polymer (PAA-12). Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was performed at 60° C. for 4 hours. At this time, the amount of pyridine and acetic anhydride added was adjusted to 0.6 times the amount used in Synthesis Example 56. After the dehydration ring-closure reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 15% by mass of a polyimide (which was designated as polymer (PI-5)) having an imidization rate of about 50%.

[0308] [Synthesis Example 61]

[0309] 70 mol parts of compound (b-1) and 30 mol parts of compound (b-2) as tetracarboxylic dianhydride, 20 mol parts of compound (DA-1) as diamine compound, 20 mol parts of compound (DA-11) and 60 mol parts of compound (a-7) were dissolved in NMP, and reacted at 40°C for 6 hours to obtain a solution containing 15% by mass of polyamic acid. Subsequently, NMP was added to the obtained polyamic acid solution to prepare a solution with a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closure reaction was carried out at 60°C for 4 hours. After the dehydration ring-closure reaction, the solvent in the system was replaced with new NMP, thereby obtaining a solution containing 15% by mass of polyimide (which is set to polymer (pii-1)) with an imidization rate of about 80%.

[0310] <Preparation and evaluation of liquid crystal alignment agents>

[0311] [Example 1: Light FFS Type Liquid Crystal Display Element]

[0312] 1. Preparation of Liquid Crystal Alignment Agent

[0313] A solution containing a polymer (PAA-1) obtained in Synthesis Example 1 with a solid content of 30 parts by mass, a solution containing a polymer (PAA-14) obtained in Synthesis Example 17 with a solid content of 70 parts by mass, 2 parts by mass of the compound (N-1), and 1 part by mass of the compound (N-3) were mixed, and diluted with NMP, N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (BL), and butyl cellosolve (BC) to prepare a solution having a solvent composition of NMP / NEP / BL / BC = 15 / 45 / 20 / 20 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered with a filter having a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-1).

[0314] 2. Manufacture of FFS-type liquid crystal display element using photo-alignment method

[0315] Prepare a glass substrate (set as the first substrate) on which a flat electrode (bottom electrode), an insulating layer and a comb-shaped electrode (top electrode) are sequentially stacked on a single surface, and a glass substrate (set as the second substrate) without an electrode. Then, use a rotator to apply a liquid crystal alignment agent (AL-1) on the electrode forming surface of the first substrate and one of the substrate surfaces of the second substrate, respectively, and heat (pre-bake) on a hot plate at 80°C for 1 minute. After that, dry (post-bake) for 30 minutes in a 230°C oven in which nitrogen is replaced in the chamber to form a coating with an average film thickness of 0.1 μm. For the obtained coating, use a Hg-Xe lamp to irradiate 5,000 J / m of ultraviolet rays containing a linearly polarized bright line of 254 nm from the normal direction of the substrate. 2 The photo-alignment treatment was performed. The irradiation amount was a value measured using a light meter with a wavelength of 254 nm as a reference. Then, the coating film subjected to the photo-alignment treatment was heated in a clean oven at 230° C. for 30 minutes to perform a heat treatment, thereby forming a liquid crystal alignment film.

[0316] Next, for one of the pair of substrates on which a liquid crystal orientation film is formed, an epoxy resin adhesive containing alumina balls with a diameter of 3.5 μm is applied by screen printing to the outer edge of the surface having the liquid crystal orientation film. After that, the substrates are overlapped and crimped in such a way that the projection direction of the polarization axis toward the substrate surface becomes antiparallel when irradiated with light, and the adhesive is thermally cured at 150°C for 1 hour. Subsequently, a negative liquid crystal (MLC-6608 manufactured by Merck) is filled between a pair of substrates from the liquid crystal injection port, and the liquid crystal injection port is sealed with an epoxy adhesive to obtain a liquid crystal unit. Furthermore, in order to remove the flow orientation during the injection of the liquid crystal, it is heated at 120°C and then slowly cooled to room temperature. In addition, by respectively adjusting the ultraviolet irradiation amount after post-baking to 100 J / m 2 ~10,000J / m 2 The series of operations are implemented by making changes within a range to manufacture three or more liquid crystal units with different ultraviolet irradiation amounts, and the liquid crystal unit with the exposure amount (optimal exposure amount) showing the best orientation characteristics is used for the following evaluation of liquid crystal orientation, orientation uniformity and VHR reliability.

[0317] 3. Evaluation of liquid crystal orientation based on retardation change rate

[0318] The liquid crystal cell manufactured in 2. was set at 27,000 cd / m 2The liquid crystal orientation is evaluated by standing on a high-brightness backlight for 500 hours. The rate of change of the delay before and after the backlight irradiation is used to evaluate the liquid crystal orientation. First, for the liquid crystal unit manufactured in 2., the delay is measured using Axoscan manufactured by Opto Science, and the rate of change of the delay before and after the backlight irradiation is calculated using the following formula (z-1). The smaller the rate of change α, the more stable the liquid crystal orientation and the better the reliability. The case where the rate of change α is less than 1% is set to "good (○)", the case where it is greater than 1% and less than 2% is set to "acceptable (△)", and the case where it is greater than 2% is set to "poor (×)".

[0319] α=Δθ / θ1···(z-1)

[0320] (In formula (z-1), Δθ represents the retardation difference before and after irradiation, and θ1 represents the retardation value before irradiation)

[0321] As a result, the evaluation of the liquid crystal orientation (orientation stability) of the above-mentioned Example was "good (○)".

[0322] 4. Evaluation of orientation uniformity

[0323] Using the liquid crystal unit manufactured in 2., the delay was measured at any 20 points in one pixel surface by Axoscan manufactured by Opto Science, and the standard deviation was calculated. Regarding the evaluation, the case where the standard deviation of the delay was 0.05 or less was set as "good (○)", the case where it was greater than 0.05 and less than 0.07 was set as "acceptable (△)", and the case where it was greater than 0.07 was set as "poor (×)". As a result, the alignment uniformity of the embodiment was evaluated as "good (○)".

[0324] 5. Evaluation of VHR reliability

[0325] For the liquid crystal unit manufactured in 2. above, the reliability of the voltage holding ratio is evaluated. The evaluation is performed as follows. First, after applying a voltage of 1V for 60 microseconds to the liquid crystal unit, the voltage holding ratio (VHR1) is measured 1670 milliseconds after the application is released. Then, after irradiating the liquid crystal unit with a cold cathode fluorescent lamp (CCFL) (backlight) for one week at 60°C, it is left to stand at room temperature and naturally cool to room temperature. After cooling, after applying a voltage of 1V for 60 microseconds to the liquid crystal unit, the voltage holding ratio (VHR2) is measured 1670 milliseconds after the application is released. In addition, the measuring device uses a VHR measuring device "VHR-1" manufactured by Toyo Technica Corporation. The rate of change of VHR at this time (ΔVHR) is calculated based on the difference between VHR1 and VHR2 (ΔVHR=VHR1-VHR2), and the VHR reliability is evaluated based on ΔVHR. The case where ΔVHR was less than 15% was judged as "good (○)", the case where ΔVHR was between 15% and 20% was judged as "acceptable (△)", and the case where ΔVHR was greater than 20% was judged as "poor (×)". As a result, the VHR reliability of the embodiment was evaluated as "acceptable (△)".

[0326] 6. Evaluation of film strength (adhesion to substrate)

[0327] Use a spinner to apply the liquid crystal alignment agent (AL-1) prepared in 1. on a glass substrate, pre-bake for 2 minutes on a hot plate at 80°C, and then heat for 30 minutes in a 230°C oven in which the air in the chamber has been replaced with nitrogen (post-bake), thereby forming a coating with an average film thickness of 0.10 μm. Two glass substrates with a coating are prepared by repeating the same operation as described above. On the coating of one glass substrate with a coating, an ODF sealant (manufactured by Sekisui Chemical Co., Ltd., S-WB42) is applied in such a way that the width of the sealant becomes 1 mm, and the coating of the other glass substrate is bonded in such a way that it contacts the ODF sealant. Thereafter, irradiate with 30,000 J / m using a metal halide lamp. 2 After being exposed to light at 365 nm, the film was heated in an oven at 120°C for 1 hour. After heating, the adhesion strength was measured using a tensile compression tester (model: SDWS-0201-100SL) manufactured by Imada Manufacturing Co., Ltd. to evaluate the adhesion of the film to the substrate. For the evaluation, the adhesion strength was 200 N / cm 2 The above cases were rated as "good (○)", and 100 N / cm 2 Above and less than 200N / cm 2 If the value is less than 100 N / cm, set it as “OK (△)”. 2 The case of "bad (×)" was set as "bad (×)". As a result, the adhesion force in the embodiment was 212 N / cm2 , which is rated as “good (○)”.

[0328] 7. Evaluation of film strength (friction resistance)

[0329] The liquid crystal alignment agent (AL-1) prepared in 1. is applied to a glass substrate using a rotator and heated (pre-baked) on a hot plate at 110°C for 3 minutes. Afterwards, it is dried (post-baked) for 30 minutes in an oven at 230°C where nitrogen is replaced in the warehouse to form a coating having an average film thickness of 0.08 μm. For the coating, the haze value of the coating is measured using a haze meter. Subsequently, the coating is subjected to 5 friction treatments at a roller speed of 1000 rpm, a stage moving speed of 3 cm / second, and a hair pressing length of 0.3 mm using a friction machine having a roller wound with cotton cloth. Afterwards, the haze value of the liquid crystal alignment film is measured using a haze meter, and the difference (haze change value) from the haze value before the friction treatment is calculated. When the haze value of the film before the friction treatment is set to Hz1 (%) and the haze value of the film after the friction treatment is set to Hz2 (%), the haze change value is expressed by the following formula (z-2).

[0330] Haze change value (%) = Hz2-Hz1···(z-2)

[0331] The case where the haze change value of the liquid crystal alignment film is less than 0.5 is evaluated as "good (○)", the case where the haze change value is greater than 0.5 and less than 1.5 is evaluated as "acceptable (△)", and the case where it is greater than 1.5 is evaluated as "poor (×)". If the haze change value is less than 1.5 (more preferably less than 0.5), it can be said that the film strength is sufficiently high and the friction resistance is high, that is, the mechanical properties of the film are good. As a result, the evaluation is "good (○)" in the embodiment.

[0332] [Example 2 to Example 70 and Comparative Examples 1 to 8]

[0333] The composition of the liquid crystal aligning agent is changed as shown in Table 2 and Table 3, and the liquid crystal aligning agent is prepared in the same manner as in Example 1. In addition, using the obtained liquid crystal aligning agent, an FFS type liquid crystal unit is manufactured by a photo-alignment method in the same manner as in Example 1, and various evaluations are performed. The results are shown in Table 2 and Table 3. In addition, the numerical value in the mass ratio column represents the blending ratio (mass parts) of each compound (polymer, additive) in terms of solid content relative to 100 parts by mass of the total amount of the polymer component used in the preparation of the liquid crystal aligning agent.

[0334] [Table 2]

[0335]

[0336] [Table 3]

[0337]

[0338] As shown in Tables 2 and 3, in Examples 1 to 70 using a liquid crystal alignment agent containing an imide polymer (first polymer) and an imide polymer (second polymer), the balance of liquid crystal orientation (orientation stability and orientation uniformity), VHR reliability, and film strength (film adhesion and friction resistance) is well improved compared to Comparative Examples 1 to 8 using a liquid crystal alignment agent that does not contain at least one of the first polymer and the second polymer. The imide polymer (first polymer) contains a structural unit (I) derived from a diamine having a partial structure represented by the formula (1) and has a structural unit (T) derived from a compound represented by the formula (3) in a specified proportion or more, and the imide polymer (second polymer) contains a structural unit (II) derived from a diamine having a partial structure represented by the formula (2).

[0339] Among them, in Examples 2 to 6, 9 to 21, 24 to 32, 41, 50 to 51 in Examples 1 to 70, the liquid crystal orientation, VHR reliability and film strength were evaluated as "good (○)", showing that the electrical properties (VHR reliability) and film strength can be improved while maintaining the liquid crystal orientation. It is believed that this is because the first polymer containing the structural unit (I) is a polymer obtained by using four or more diamine compounds, which can further improve the liquid crystal orientation and film strength, and the second polymer containing the structural unit (II) has a strongly basic nitrogen-containing group protected by a leaving group, which can improve the electrical properties while maintaining the liquid crystal orientation.

[0340] [Example 71: Rubbing FFS Type Liquid Crystal Display Element]

[0341] 1. Preparation of Liquid Crystal Alignment Agent

[0342] A solution containing a polymer (PAA-1) obtained in Synthesis Example 1 with a solid content of 40 parts by mass, a solution containing a polymer (PAA-14) obtained in Synthesis Example 17 with a solid content of 60 parts by mass, 2 parts by mass of the compound (N-1), and 1 part by mass of the compound (N-3) were mixed, and diluted with NMP, NEP, and butyl cellosolve (BC) to prepare a solution having a solvent composition of NMP / NEP / BC = 20 / 40 / 40 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered with a filter having a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-79).

[0343] 2. Manufacture of FFS-type liquid crystal display elements using the rubbing method

[0344] Prepare a glass substrate (set as the first substrate) on which a flat electrode (bottom electrode), an insulating layer and a comb-shaped electrode (top electrode) are sequentially stacked on a single surface, and a glass substrate (set as the second substrate) without an electrode. Then, a liquid crystal alignment agent (AL-79) is applied to the electrode forming surface of the first substrate and the single surface of the second substrate using a rotator, and heated (pre-baked) for 3 minutes using a hot plate at 110°C. After that, it is dried (post-baked) for 30 minutes in a 230°C oven in which nitrogen is replaced in the warehouse to form a coating with an average film thickness of 0.08μm. Then, for the surface of the coating, a friction machine having a roller wound with a rayon cloth is used to perform friction treatment at a roller speed of 1000rpm, a stage moving speed of 3cm / second, and a hair pressing length of 0.3mm. After that, ultrasonic cleaning is performed in ultrapure water for 1 minute, followed by drying in a 100°C clean oven for 10 minutes, thereby obtaining a pair of substrates with a liquid crystal alignment film.

[0345] Then, for a pair of substrates having a liquid crystal alignment film, a liquid crystal injection port is reserved at the edge of the surface on which the liquid crystal alignment film is formed, and an epoxy resin adhesive containing alumina balls with a diameter of 3.5 μm is applied by screen printing. After that, the substrates are overlapped and crimped, and the adhesive is thermally cured at 150°C for 1 hour. Then, after a negative liquid crystal (Merck, MLC-6608) is filled into the gap between a pair of substrates from the liquid crystal injection port, the liquid crystal injection port is sealed with an epoxy adhesive. Furthermore, in order to remove the flow orientation during liquid crystal injection, it is heated at 120°C and then slowly cooled to room temperature to produce a liquid crystal unit. In addition, when a pair of substrates are overlapped, the rubbing directions of each substrate are made antiparallel.

[0346] 3. Evaluation

[0347] The liquid crystal cell produced in 2. was evaluated for liquid crystal orientation by the same method as in Example 1. In addition, using a liquid crystal aligning agent (AL-79), film strength (adhesion and abrasion resistance of the film) was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0348] [Example 72 to Example 82 and Comparative Example 9 to Comparative Example 12]

[0349] The composition of the liquid crystal alignment agent was changed as shown in Table 4, and the liquid crystal alignment agent was prepared in the same manner as in Example 71. In addition, using the obtained liquid crystal alignment agent, an FFS type liquid crystal unit was manufactured by a friction method in the same manner as in Example 71, and various evaluations were performed. The results are shown in Table 4. In addition, the numerical values ​​in the mass ratio column in Table 4 represent the blending ratio (mass parts) of each compound (polymer, additive) in terms of solid content relative to 100 parts by mass of the total amount of the polymer component used in the preparation of the liquid crystal alignment agent.

[0350] [Table 4]

[0351]

[0352] As shown in Table 4, in Examples 71 to 82 using a liquid crystal alignment agent containing an imide polymer (first polymer) and an imide polymer (second polymer), the balance of liquid crystal orientation (orientation stability and orientation uniformity), VHR reliability, and film strength (film adhesion and friction resistance) is well improved compared to Comparative Examples 9 to 12 using a liquid crystal alignment agent that does not contain at least one of the first polymer and the second polymer. The imide polymer (first polymer) contains a structural unit (I) derived from a diamine having a partial structure represented by the formula (1) and has a structural unit (T) derived from a compound represented by the formula (3) in a specified proportion or more, and the imide polymer (second polymer) contains a structural unit (II) derived from a diamine having a partial structure represented by the formula (2).

[0353] It is clear from the above results that a liquid crystal orientation agent comprising an imide polymer, i.e., an imide polymer containing a structural unit (I) derived from a diamine having a partial structure represented by the formula (1) and having a structural unit (T) derived from a compound represented by the formula (3) in a predetermined proportion or more, and an imide polymer, i.e., an imide polymer containing a structural unit (II) derived from a diamine having a partial structure represented by the formula (2), can obtain a liquid crystal element having excellent liquid crystal orientation (orientation stability, orientation uniformity) and VHR reliability, and can form a liquid crystal orientation film having excellent mechanical properties.

Claims

1. A liquid crystal alignment agent, comprising a first polymer and a second polymer as imide polymers selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, The first polymer contains a structural unit (I) derived from a diamine having a partial structure represented by the following formula (1) and a structural unit (T) derived from a compound represented by the following formula (3), wherein the content ratio of the structural unit (T) is 75 mol% or more relative to the total amount of the structural units derived from the tetracarboxylic acid derivative contained in the first polymer, The second polymer is a polymer different from the first polymer and contains a structural unit (II) derived from a diamine having a partial structure represented by the following formula (2). In formula (1), D 1 is a monovalent organic group with a carbon number of 5 or more; R 1 is a single bond, -O- or -NR 3a -; R 2 is a single bond or -NR 3b -; R 3a and R 3b are independently a hydrogen atom or a monovalent organic group having 1 or more carbon atoms; R 4 and R 5 are independently substituted or unsubstituted divalent hydrocarbon groups or divalent heterocyclic groups; "*" represents a bond; In formula (2), D 2 is a monovalent organic group having 5 or more carbon atoms; d is 1 or 2; when d is 1, R 6 and R 7 Independently of each other, 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atom to which it is bonded together forms a monocyclic or condensed heterocyclic structure; when d is 2, R 6 and R 7 Medium R 6 is ">C(R 10 )-* 1 " represents a trivalent group, a trivalent alicyclic group or a trivalent aromatic ring group, wherein "* 1 " indicates the bond on the nitrogen side, R 7 "-C(R 11 )(R 12 )-", a divalent alicyclic group or a divalent aromatic ring group, or represents R 6 and R 7 Combined with R 6 and R 7 The nitrogen atom to which it is bonded together forms a monocyclic or condensed heterocyclic structure; R 10 , R 11 and R 12 are independently a hydrogen atom, a monovalent hydrocarbon group or a substituent; R 8 is a hydrogen atom or an organic group having 1 to 4 carbon atoms; a is 1 or 2; b is 0 or 1; c is 0 or 1; wherein a+b+c=2 is satisfied; in the case of R 6 and R 7 Combined with R 6 and R 7 In the case of a monocyclic or condensed heterocyclic structure formed by the nitrogen atom to which the bond is attached, a=1, b=1 and c=0; "*" represents a bonding bond; In formula (3), R 15 , R 16 , R 17 and R 18 are independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent group having 1 to 6 carbon atoms and having a fluorine atom, or a phenyl group; wherein R 15 , R 16 , R 17 and R 18 At least one of the groups is a group different from a hydrogen atom.

2. The liquid crystal alignment agent according to claim 1, wherein D in the formula (1) 1 And D in the formula (2) 2 It is a monovalent thermally detached group.

3. The liquid crystal alignment agent according to claim 1, wherein R in the formula (1) 4 and R 5 One or both of them have a substituted or unsubstituted divalent chain hydrocarbon group, and the chain hydrocarbon group and R in the formula (1) 1 or R 2 Bond. 4 . The liquid crystal alignment agent according to claim 1 , wherein the first polymer has a partial structure represented by the formula (1) in a main chain. 5 . The liquid crystal alignment agent according to claim 1 , wherein the first polymer includes four or more structural units derived from a diamine compound, including the structural unit (I). 6 . The liquid crystal alignment agent according to claim 1 , wherein the nitrogen atom in the formula (2) constitutes a part of the main chain of the second polymer, or the nitrogen atom in the formula (2) is bonded to a carbon atom constituting a part of the main chain of the second polymer.

7. The liquid crystal alignment agent according to claim 1, wherein the second polymer comprises a structural unit (II-1) derived from a diamine as the structural unit (II), wherein the diamine has a "-C(R 11 )(R 12 )-”or”>C(R 10 )-* 1 "Part of the structure.

8. The liquid crystal alignment agent according to claim 7, wherein the structural unit (II-1) is a structural unit derived from a diamine represented by the following formula (4): In formula (4), Ar 1 and Ar 2 are independently divalent aromatic ring groups; X 1 and X 2 are independently a divalent chain hydrocarbon group or a divalent group in which a part of the methylene groups in the chain hydrocarbon group is substituted with -O-, -S-, -CO- or -COO-; 1 and Y 2 are independently a group having a "-C(R 11 )(R 12 )-”or”>C(R 10 )-* 1 "The base of the partial structure; X 3 is a divalent organic group; r is an integer from 0 to 3; when r is 2 or 3, the multiple X 3 and multiple Y 2 Same as or different from each other. 9 . The liquid crystal aligning agent according to claim 1 , further comprising a cross-linking agent. 10 . A liquid crystal alignment film formed using the liquid crystal alignment agent according to claim 1 . A liquid crystal element comprising the liquid crystal alignment film according to claim 10 .

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