Liquid crystal alignment agent, liquid crystal alignment film and its manufacturing method, and liquid crystal element

Abstract

To provide a liquid crystal alignment agent capable of forming a liquid crystal alignment film excellent in adhesion with a substrate and producing a liquid crystal element excellent in a liquid crystal alignment property and touch panel resistance.SOLUTION: A liquid crystal alignment agent contains a polymer [P] having a partial structure represented by a formula (1). Ar1 and Ar2 represent divalent aromatic ring groups. X1 and X2 represent -NR3-, -O-, -S-, *1-NR3-CO-, or *1-O-CO-. "*1" represents a bond bonding to Ar1 or Ar2. R1 or R2 represents a divalent hydrocarbon group. A1 represents -NR4-, -NR4-CO-*2, -CO-NR4-*2, -NR4-CO-NR5-*2, -NR5-CO-NR4-*2, -CH2-O-CO-*2, -CO-O-CH2-*2 or -O-. If all of A1 in the formula (1) are -O-, X1 and X2 represent -NR3-, *1-NR3-CO- or *1-O-CO-.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a method for producing the same, and a liquid crystal device. [Background technology]

[0002] Liquid crystal elements are used in a wide range of applications, from relatively large display devices such as liquid crystal televisions and information displays to small display devices such as smartphones. The performance of a liquid crystal element is determined by various characteristics such as the alignment of the liquid crystal, the magnitude of the pretilt angle, and the voltage holding ratio. To improve the performance of liquid crystal elements, improvements have been made to liquid crystal materials as well as liquid crystal alignment films for aligning the liquid crystal in a certain direction (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses that a liquid crystal aligning agent containing a polyamic acid, which is a reaction product of a tetracarboxylic dianhydride and a diamine, and a derivative thereof, contains a polyamic acid obtained by using bis(4-aminophenoxy)adipamide as the diamine. Patent Document 2 discloses that a polyimide obtained by using di-tert-butyl adipoylbis[(4-aminophenethyl)carbamate] as the diamine is contained in a liquid crystal aligning agent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-132326 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-145954 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to further improve the quality of liquid crystal devices, the present inventors have conducted research and discovered that by producing a polyamic acid using a diamine having a partial structure in which an alkylene structure is bonded to an aromatic ring via a specific heteroatom-containing group, a liquid crystal alignment film that exhibits good liquid crystal alignment properties can be obtained whether the liquid crystal alignment film is produced by rubbing treatment or photo-alignment treatment. On the other hand, it has been found that imidization of polyamic acid can deteriorate the mechanical properties of the liquid crystal alignment film and / or reduce the adhesion of the liquid crystal alignment film to the substrate, leaving room for further improvement.

[0006] For example, in mobile applications such as smartphones and tablet PCs, efforts are being made to narrow the frame to achieve both a larger touch panel operating area and a smaller display device. One known method for narrowing the frame is to form a liquid crystal alignment film over the entire surface of the substrate, then apply a sealant to the liquid crystal alignment film and bond the substrates together. However, placing the sealant on the liquid crystal alignment film increases the likelihood of stress being applied to the alignment film where the sealant is applied. Therefore, if the liquid crystal alignment film has poor mechanical properties or poor adhesion to the substrate, there is a concern that the substrates may easily peel off from each other.

[0007] In recent years, liquid crystal display devices have rapidly spread to mobile and in-vehicle applications. Liquid crystal elements for smartphones and in-vehicle applications must not only have excellent display quality, but also be resistant to degradation of display quality due to exposure to external forces and have good touch panel characteristics, i.e., good touch panel durability (also known as keystroke durability).

[0008] The present invention has been made in consideration of the above-mentioned problems, and has as its main object to provide a liquid crystal alignment agent that can form a liquid crystal alignment film that has excellent adhesion to a substrate and can produce a liquid crystal element that has excellent liquid crystal alignment properties and touch panel resistance. [Means for solving the problem]

[0009] The present invention employs the following means to solve the above problems.

[0010] <1> A liquid crystal aligning agent comprising a polymer [P] having a partial structure represented by the following formula (1) in its main chain: [ka] (In formula (1), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. 1 and X 2 are each independently -NR 3 -, -O-, -S-, * 1 -NR 3 -CO- or * 1 -O-CO-. R 3 is a hydrogen atom or a monovalent organic group. 1 " is Ar 1 or Ar 2 Represents a bond with R. 1 and R 2 are each independently a divalent hydrocarbon group. 1 is -NR 4 -, -NR 4 -CO-* 2 , -CO-NR 4 -* 2 , -NR 4 -CO-NR 5 -* 2 , -NR 5 -CO-NR 4 -* 2 , -CH2-O-CO-* 2 , -CO-O-CH2-* 2 Or -O-. R 4 is a monovalent organic group. 5 is a hydrogen atom or a monovalent organic group. 2 " is R 2 However, all A in formula (1) 1 If -O-, then X 1 and X 2 are each independently -NR 3 -, * 1 -NR 3 -CO- or * 1-O-CO-. n is an integer of 1 to 3. When n is 2 or 3, multiple R 1 are the same or different, and multiple A 1 are the same or different. "*" represents a bond.) <2> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <3> the above <2> A liquid crystal element comprising the liquid crystal alignment film. [Effects of the Invention]

[0011] According to the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent adhesion to a substrate can be formed, and a liquid crystal device having excellent liquid crystal alignment properties and touch panel resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0012] Liquid crystal alignment agent Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that may be arbitrarily blended as necessary will be described.

[0013] In this specification, the term "hydrocarbon group" includes chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain-like hydrocarbon group" refers to a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed solely of a chain structure. However, it may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, it does not necessarily have to be composed solely of an alicyclic hydrocarbon structure and may also contain a chain structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not necessarily have to be composed solely of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it. The term "aliphatic hydrocarbon group" refers to a chain-like hydrocarbon group and an alicyclic hydrocarbon group. The term "aromatic ring" refers to an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The term "organic group" refers to an atomic group formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0014] The liquid crystal aligning agent of the present disclosure contains a polymer [P] having a partial structure represented by the following formula (1) (hereinafter also referred to as "partial structure (A)"). [ka] (In formula (1), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. 1 and X 2 are each independently -NR 3 -, -O-, -S-, * 1 -NR 3 -CO- or * 1 -O-CO-. R 3 is a hydrogen atom or a monovalent organic group. 1 " is Ar 1 or Ar 2 Represents a bond with R. 1 and R 2 are each independently a divalent hydrocarbon group. 1 is -NR 4 -, -NR 4 -CO-* 2 , -CO-NR 4 -* 2 , -NR 4 -CO-NR 5 -* 2 , -NR 5 -CO-NR 4 -* 2 , -CH2-O-CO-* 2 , -CO-O-CH2-* 2 Or -O-. R 4 is a monovalent organic group. 5 is a hydrogen atom or a monovalent organic group. 2 " is R 2 However, all A in formula (1) 1 If -O-, then X 1 and X 2 are each independently -NR 3 -, * 1 -NR 3 -CO- or * 1 -O-CO-. n is an integer of 1 to 3. When n is 2 or 3, multiple R1 are the same or different, and multiple A 1 are the same or different. "*" represents a bond.)

[0015] <Polymer [P]> Regarding substructure (A) In formula (1), Ar 1 and Ar 2 Examples of the divalent aromatic ring group represented by the formula (Ar) include a divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group. 1 and Ar 2 The aromatic ring constituting the divalent aromatic ring group represented by the formula (I) may be a single ring or a condensed ring, and may have a structure in which two or more single rings or condensed rings are connected by a single bond (for example, a biphenyl ring structure). 1 and Ar 2 The divalent aromatic ring group represented by the formula (I) may have a substituent at the aromatic ring portion. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom).

[0016] Ar 1 and Ar 2 Specific examples of when Ar is a divalent aromatic ring group include, as the divalent aromatic hydrocarbon group, a group obtained by removing any two hydrogen atoms bonded to carbon atoms constituting the ring in a benzene ring structure, a biphenyl ring structure, a naphthalene ring structure, or an anthracene ring structure, or a ring structure obtained by introducing a substituent into these rings; and as the divalent nitrogen-containing aromatic heterocyclic group, a group obtained by removing any two hydrogen atoms bonded to carbon atoms constituting the ring in a pyridine ring structure, a pyrimidine ring structure, a pyridazine ring structure, or a pyrazine ring structure, or a ring structure obtained by introducing a substituent into these rings. 1 and Ar 2 From the viewpoint of liquid crystal alignment properties and voltage retention characteristics, is preferably a divalent aromatic hydrocarbon group, and more preferably a divalent group having a benzene ring structure or a biphenyl ring structure.

[0017] X 1and X 2 The group represented by -NR 3 -or* 1 -NR 3 -CO-, R 3 Examples of the monovalent organic group represented by the formula (I) include monovalent hydrocarbon groups having 1 to 10 carbon atoms and monovalent thermally eliminable groups. Specific examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, and aryl groups having 6 to 10 carbon atoms. Of these, alkyl groups and phenyl groups having 1 to 3 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms are more preferred.

[0018] R 3 Specific examples of when the monovalent organic group represented by the formula (I) is a monovalent thermally detachable group include a tert-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group, a 2-(trimethylsilyl)ethoxycarbonyl group, etc. Among these, the Boc group is particularly preferred because it has excellent thermal detachment properties and can minimize the amount of the detached structure remaining in the film.

[0019] R 3 Of the above, is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a monovalent thermally detachable group, and more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a tert-butoxycarbonyl group.

[0020] X 1 and X 2 From the viewpoint of obtaining a liquid crystal device exhibiting good liquid crystal alignment, -NR 3 It is preferable that all A in formula (1) are -, -O- or -S-. 1 When n is 1, one A is 1 When n is 2 or 3, multiple A 1 If all of are -O-, then X 1 and X 2 are independent of each other, -NR 3 -, * 1 -NR 3-CO- or * 1 -O-CO- and -NR 3 - is preferred.

[0021] R 1 and R 2 Examples of the divalent hydrocarbon group represented by the formula (I) include a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. 1 and R 2 is preferably a divalent aliphatic hydrocarbon group. Specific examples of the divalent aliphatic hydrocarbon group include a linear or branched divalent chain hydrocarbon group having 1 to 20 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0022] R 1 and R 2 Among these, the divalent hydrocarbon group represented by is preferably a linear or branched divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a linear or branched divalent chain hydrocarbon group having 1 to 10 carbon atoms. R 1 and R 2 It is particularly preferred that R is a linear alkanediyl group. 1 and R 2 The number of carbon atoms is preferably 8 or less, more preferably 5 or less, and even more preferably 3 or less, from the viewpoint of obtaining a liquid crystal element that exhibits good liquid crystal alignment properties while sufficiently improving the touch panel resistance and adhesion to the substrate.

[0023] A 1 The group represented by -NR 4 -, -NR 4 -CO-* 2 , -CO-NR 4 -* 2 , -NR 4 -CO-NR 5 -* 2 or -NR 5 -CO-NR 4 -* 2 If R4 and R 5 Examples of the monovalent organic group represented by the formula (I) include monovalent hydrocarbon groups having 1 to 10 carbon atoms and monovalent thermally detachable groups. Specific and preferred examples of the monovalent hydrocarbon groups having 1 to 10 carbon atoms and monovalent thermally detachable groups are given in the section R 3 The specific examples and preferred examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms and the monovalent thermally eliminable group described above as the monovalent organic group represented by the following formula are the same as those of the monovalent hydrocarbon group having 1 to 10 carbon atoms and the monovalent thermally eliminable group.

[0024] R 4 and R 5 is preferably an alkyl group having 1 to 3 carbon atoms or a monovalent thermally detachable group, more preferably an alkyl group having 1 to 3 carbon atoms or a tert-butoxycarbonyl group.

[0025] A 1 From the viewpoint of obtaining a liquid crystal device exhibiting good adhesion and liquid crystal alignment, -NR 4 -, -NR 4 -CO-* 2 , -CO-NR 4 -* 2 , -NR 4 -CO-NR 5 -* 2 , -NR 5 -CO-NR 4 -* 2 , -CH2-O-CO-* 2 or -CO-O-CH2-* 2 is preferred, and -NR 4 -, -CH2-O-CO-* 2 or -CO-O-CH2-* 2 More preferably, -CH2-O-CO-* 2 or -CO-O-CH2-* 2 is more preferred.

[0026] In addition, in order to obtain a liquid crystal alignment film having high adhesion to the substrate, the "-X 1 -(R 1 -A 1 ) n -R 2 -X 2The spacer length in the chain structure represented by "-" is preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more. The "spacer length" here refers to the number of X per one partial structure (A). 1 The number of (1) and X 2 The number of (1) and A 1 The number of (n) and R 1 and R 2 For example, the spacer length of the partial structure (A) in the compound represented by the following formula (4-1) is 8.

[0027] The method for producing polymer [P] is not particularly limited as long as it can introduce partial structure (A) into at least one of the main chain and side chain. It is preferable that polymer [P] have partial structure (A) in the main chain, as this can further improve the adhesion of the liquid crystal alignment film to the substrate, as well as the liquid crystal alignment property and touch panel resistance in liquid crystal elements. Here, the "main chain" of a polymer refers to the "trunk" portion of the polymer, which is the longest chain of atoms. Note that this "trunk" portion is allowed to contain a ring structure. In other words, "having partial structure (A) in the main chain" means that partial structure (A) constitutes a part of the main chain. Note that when polymer [P] has partial structure (A) in the main chain, partial structure (A) may be present not only in the main chain but also in the side chain. The "side chain" refers to the portion branched from the "trunk" of the polymer.

[0028] The polymer [P] is preferably produced by a method of polymerizing a monomer having the partial structure (A), since the partial structure (A) can be easily introduced into the polymer. The monomer having the partial structure (A) is preferably a diamine compound having the partial structure (A) (hereinafter also referred to as "specific diamine"), since it can form a liquid crystal alignment film having high affinity with liquid crystals and high mechanical strength, and there is a high degree of freedom in selecting the monomer.

[0029] The specific diamine may be a compound having the partial structure (A) and two primary amino groups, and the structure of the other parts is not particularly limited. A preferred specific example of the specific diamine is a compound represented by the following formula (2). That is, the polymer [P] preferably contains a structural unit derived from the compound represented by the following formula (2). [ka] (In formula (2), Ar 1 , Ar 2 , X 1 , X 2 , R 1 , R 2 , A 1 and n have the same meanings as in formula (1) above.

[0030] Specific examples of the specific diamine include compounds represented by the following formulas (4-1) to (4-34): In the formulas, "Boc" represents a tert-butoxycarbonyl group (the same applies hereinafter). [ka] [ka] [ka] [ka] [ka]

[0031] In the polymer [P], the content of the structural unit derived from a monomer having the partial structure (A) (hereinafter also referred to as "structural unit (a1)") is preferably 2 molar parts or more relative to 100 molar parts of the total amount of the monomer units contained in the polymer [P], from the viewpoint of obtaining a liquid crystal alignment film with high film density and a liquid crystal device exhibiting good liquid crystal alignment properties. The content of the structural unit (a1) is more preferably 5 molar parts or more, and even more preferably 10 molar parts or more, relative to 100 molar parts of the total amount of the monomer units contained in the polymer [P]. The content of the structural unit (a1) can be appropriately set depending on the main chain of the polymer [P], and is, for example, 50 molar parts or less relative to 100 molar parts of the total amount of the monomer units contained in the polymer [P]. The polymer [P] may contain only one type of structural unit (a1), or two or more types of structural units (a1).

[0032] About the polymer [P] The main chain of the polymer [P] is not particularly limited. In terms of forming a highly reliable liquid crystal alignment film having high affinity with liquid crystals and mechanical strength, the polymer [P] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0033] (Polyamic acid) When the polymer [P] is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid [P]") can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

[0034] (Tetracarboxylic acid dianhydride) Examples of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid [P] include aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, and aromatic tetracarboxylic acid dianhydrides.

[0035] Specific examples of these include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-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, Examples of suitable tetracarboxylic dianhydrides include 4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, and 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride; aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-carbonyldiphthalic anhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride; and the tetracarboxylic dianhydrides described in JP 2010-97188 A can be used. Tetracarboxylic dianhydrides can be used alone or in combination.

[0036] The tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid [P] preferably contains at least one selected from the group consisting of aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides, and more preferably contains an alicyclic tetracarboxylic acid dianhydride, in order to obtain a liquid crystal alignment film that has high solubility and exhibits good liquid crystal alignment properties and electrical properties. The proportion of the alicyclic tetracarboxylic acid dianhydride used is preferably 10 mol % or more, more preferably 20 mol % or more, and even more preferably 40 mol % or more, based on the total amount of tetracarboxylic acid dianhydrides used in the synthesis of the polyamic acid [P].

[0037] (diamine compounds) The diamine compound used in the synthesis of the polyamic acid [P] may be the specific diamine alone, or may be a diamine not having the partial structure (A) (hereinafter also referred to as "other diamines") in addition to the specific diamine. Examples of other diamines include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes.

[0038] Specific examples of other diamines include aliphatic diamines such as metaxylylenediamine and hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); and aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, and 4,4'-diaminodiphenylmethane. azobenzene, 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, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, Bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'- Dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)bisaniline, 2,6-diaminopyridine, di(5-amino-2-pyridyloxy)pentane, bis(5-aminobenzimidazole)pentane, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, diphenylamine structure-containing monomers, and monomers represented by the following formula (D-1): [ka] (In formula (D-1), R 11 and R 12 are each independently an alkanediyl group. 13 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a protecting group. n1 is an integer of 1 to 3. When n1 is 2 or 3, multiple R 12are the same or different groups, and multiple R 13 are the same or different groups. Main chain diamines such as compounds represented by the following formula: Hexadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,5-diaminobenzene, Cholestanyloxy-3,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholestanyloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholestanyloxy-3,5-diaminobenzoate, Cholesteryl 3,5-diaminobenzoate , lanostannyl 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, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO- or *-OCO- (where "*" represents X I It shows the bond with R. I is an alkanediyl group having 1 to 3 carbon atoms. II R 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. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1, provided that 1≦a+b+c≦3. A side chain type diamine or the like, such as a compound represented by Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0039] Examples of the compound represented by formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-3). Examples of the compound represented by formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). As the other diamines, one type can be used alone, or two or more types can be used in combination. [ka]

[0040] In the synthesis of the polyamic acid [P], the proportion of the specific diamine used is preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 20 mol % or more, based on the total amount of the diamine compounds used in the synthesis of the polyamic acid [P], from the viewpoints of increasing the film density of the liquid crystal alignment film and obtaining a liquid crystal element that exhibits good liquid crystal alignment properties. As the specific diamine, one type may be used alone, or two or more types may be used in combination.

[0041] (Synthesis of polyamic acid) Polyamic acid [P] can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally with a molecular weight modifier. In the synthesis reaction of polyamic acid [P], the ratio of the tetracarboxylic dianhydride to the diamine compound is preferably such that 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride are present per equivalent of the amino group of the diamine compound. Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The molecular weight modifier is preferably used in an amount of 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound used.

[0042] The synthesis reaction of the polyamic acid [P] 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 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Specific examples of such solvents include one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols. Alternatively, a mixture of one or more of these solvents with another organic solvent (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.) is preferably used. The amount of organic solvent used is preferably such that the total amount of the tetracarboxylic dianhydride and diamine is 0.1 to 50% by mass based on the total amount of the reaction solution.

[0043] In this way, a polymer solution containing the polyamic acid [P] dissolved therein is obtained. This polymer solution may be used as is for preparing a liquid crystal aligning agent, or the polyamic acid [P] contained in the polymer solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0044] Polyamic acid ester When the polymer [P] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [P]") can be obtained, for example, by a method such as [I] reacting a polyamic acid [P] with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine, or [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. The polyamic acid ester [P] 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 [P] is dissolved may be used directly for preparing a liquid crystal aligning agent, or the polyamic acid ester [P] contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0045] Polyimide When the polymer [P] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [P]") can be obtained, for example, by imidizing the polyamic acid [P] synthesized as described above through dehydration and cyclization. The polyimide [P] may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid [P] have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide [P] preferably has an imidization rate of 20 to 99%, more preferably 30 to 90%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, some of the imide rings may be isoimide rings.

[0046] The dehydration ring closure of the polyamic acid [P] is preferably carried out by dissolving the polyamic acid [P] in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as needed. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid [P]. The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring closure reaction include the organic solvents exemplified for use in the synthesis of the polyamic acid [P]. The reaction temperature for the dehydration ring closure reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide [P] may be used for preparing a liquid crystal aligning agent as it is, or the polyimide [P] may be isolated and then used for preparing a liquid crystal aligning agent.

[0047] The solution viscosity of the polymer [P] used to prepare the liquid crystal alignment agent is preferably 10 to 800 mPa·s when made into a 10% by mass solution, and more preferably 15 to 500 mPa·s. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer [P] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0048] The weight average molecular weight (Mw) of the polymer [P] measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 7 or less, more preferably 5 or less.

[0049] The content of the polymer [P] in the liquid crystal aligning agent is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the total amount of solids contained in the liquid crystal aligning agent (i.e., the total mass of the components other than the solvent of the liquid crystal aligning agent). In preparing the liquid crystal aligning agent, one type of polymer [P] may be used alone, or two or more types may be used in combination.

[0050] <Other ingredients> The liquid crystal aligning agent may contain, in addition to the polymer [P], components different from the polymer [P] (hereinafter also referred to as "other components"), if necessary.

[0051] Polymer [Q] The liquid crystal aligning agent of the present disclosure may further contain a polymer (hereinafter also referred to as "polymer [Q]") not having the partial structure (A) as a polymer component. The main skeleton of the polymer [Q] is not particularly limited. Examples of the polymer [Q] include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic polymer, styrene polymer, maleimide polymer, styrene-maleimide copolymer, etc. From the viewpoint of obtaining a highly reliable liquid crystal device, the polymer [Q] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and polymers containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond. Examples of polymers containing structural units derived from monomers having polymerizable unsaturated carbon-carbon bonds include (meth)acrylic polymers, styrene polymers, maleimide polymers, and styrene-maleimide copolymers. Among these, it is particularly preferable that the polymer [Q] be at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, in terms of facilitating localization of the polymer [P] in the upper layer, sufficiently enhancing the effect of improving the liquid crystal alignment, and facilitating adjustment of the electrical properties.

[0052] When the polymer [Q] is contained in the liquid crystal aligning agent, the content of the polymer [Q] is preferably 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the total amount of the polymer [P] and the polymer [Q]. The content of the polymer [Q] is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, per 100 parts by mass of the total amount of the polymer [P] and the polymer [Q]. The polymer [Q] may be used singly or in combination of two or more.

[0053] ·solvent The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition obtained by dispersing or dissolving the polymer [P] and other components used as needed in a suitable solvent.

[0054] As the solvent, an organic solvent is preferably used, specific examples of which 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, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of suitable solvents include ethylene glycol 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, diisopentyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. The solvent may be used alone or in combination of two or more.

[0055] In addition to the above, other components contained in the liquid crystal aligning agent include, for example, a crosslinking agent, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, etc. The blending ratio of the other components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0056] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent in the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %. A solid content concentration of 1 mass % or more is preferable in that it ensures a sufficient coating film thickness and allows a liquid crystal alignment film exhibiting better liquid crystal alignment properties to be obtained. On the other hand, a solid content concentration of 10 mass % or less allows the coating film to have an appropriate thickness, and tends to make it easier to obtain a liquid crystal alignment film exhibiting good liquid crystal alignment properties. In addition, the viscosity of the liquid crystal aligning agent becomes appropriate, which tends to improve coatability.

[0057] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is manufactured using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The liquid crystal driving method in the liquid crystal element is not particularly limited, and can be applied to various modes, such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0058] <Step 1: Formation of coating film> First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include transparent substrates made of glass, such as float glass or soda glass; or plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, one substrate with comb-shaped patterned electrodes and a counter substrate without electrodes are used. Examples of transparent conductive films that can be used include NESA films (registered trademark of PPG, USA) made of tin oxide (SnO2), and ITO films made of indium oxide-tin oxide (In2O3-SnO2).

[0059] The method for applying the liquid crystal aligning agent to the substrate is not particularly limited. The liquid crystal aligning agent can be applied to the substrate by, for example, a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coating method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, etc.

[0060] After the liquid crystal aligning agent is applied, preliminary heating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and if necessary, a baking (post-baking) step is carried out for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 280°C, more preferably 80 to 250°C. The post-baking time is preferably 5 to 200 minutes. The thickness of the film formed is preferably 0.001 to 1 μm.

[0061] <Step 2: Alignment Treatment> When producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal device, the coating film formed in step 1 is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton, nylon, or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability is preferably used. When producing a vertical alignment type liquid crystal device, the coating film formed in step 1 may be used as is as a liquid crystal alignment film, or the coating film formed in step 1 may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability.

[0062] Light irradiation for photoalignment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake step and the post-bake step. The radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is used, the irradiation direction is an oblique direction.

[0063] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, etc. The radiation dose is preferably 200 to 30,000 J / m 2 and more preferably 500 to 10,000 J / m 2After the light irradiation for imparting alignment ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0064] <Step 3: Construction of liquid crystal cell> Two substrates with liquid crystal alignment films formed thereon are prepared as described above, and a liquid crystal cell is produced by disposing a liquid crystal between the two substrates arranged opposite each other. Examples of methods for producing a liquid crystal cell include disposing two substrates with a gap between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole, and using the ODF method. Examples of sealants that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

[0065] In the PSA mode, a polymerizable compound (e.g., a polyfunctional (meth)acrylate compound) is filled into the cell gap together with the liquid crystal, and after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. In producing a PSA mode liquid crystal element, the proportion of the polymerizable compound used is 0.01 to 3 parts by mass, preferably 0.1 to 1 part by mass, per 100 parts by mass of the total liquid crystal.

[0066] When manufacturing a liquid crystal display device, a polarizing plate is subsequently attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0067] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, various display devices such as clocks, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control devices, retardation films, and the like. [Example]

[0068] Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited by the following examples.

[0069] In the following examples, the imidization rate of polyimide in the polymer solution was measured by the following method. [Imidization rate of polyimide] The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was carried out. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (F-1). Imidization rate [%] = (1 - (A 1 / (A 2 ×α)))×100 …(F-1) (In formula (1), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm, and A 2 is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0070] The abbreviations for the compounds are as follows: In the following, the "compound represented by formula (X)" may be simply referred to as "compound (X)".

[0071] (Tetracarboxylic acid dianhydride) [ka]

[0072] (diamine compounds) [ka] [ka]

[0073] <Polymer synthesis> 1. Synthesis of polyamic acid [Synthesis Example 1] 100 parts by mole of compound (TA-2) as a tetracarboxylic dianhydride and 100 parts by mole of compound (DA-1) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was allowed to react at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (referred to as polymer (PA-1)).

[0074] [Synthesis Examples 2 to 14] Polyamic acids (polymers (PA-2) to (PA-14)) were obtained by the same procedure as in Synthesis Example 1, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Tables 1 and 2. In Tables 1 and 2, the numerical values ​​for the acid dianhydrides (acid dianhydride 1 and acid dianhydride 2) represent the proportion (parts by mole) of each compound used relative to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of each polymer. The numerical values ​​for the diamines (diamine 1 and diamine 2) represent the proportion (parts by mole) of each compound used relative to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of each polymer.

[0075] [Table 1]

[0076] [Table 2]

[0077] 2. Polyimide Synthesis [Synthesis Example 15] 80 mole parts of compound (TA-2) and 20 mole parts of compound (TA-3) as tetracarboxylic dianhydrides, and 100 mole parts of compound (DA-1) as a diamine compound were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15 mass% polyamic acid. Next, NMP was added to the obtained polyamic acid solution to obtain a solution with a polyamic acid concentration of 10 mass%, and pyridine and acetic anhydride were added, followed by a dehydration ring-closing reaction at 60 °C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15 mass% polyimide (referred to as polymer (PI-1)) with an imidization rate of approximately 60%.

[0078] [Synthesis Examples 16-26] Polyimides (polymers (PI-2) to (PI-12)) were synthesized by varying the type and amount of tetracarboxylic dianhydride and diamine compound used as shown in Table 3, and adjusting the amount of pyridine and acetic anhydride to change the imidization rate as shown in Table 3. In Table 3, the values ​​for the dianhydrides (dianhydride 1 and dianhydride 2) represent the proportion (in parts by mole) of each compound used relative to 100 parts by mole of the total amount of tetracarboxylic dianhydrides used in the synthesis of each polymer. The values ​​for the diamines (diamine 1, diamine 2, and diamine 3) represent the proportion (in parts by mole) of each compound used relative to 100 parts by mole of the total amount of diamine compounds used in the synthesis of each polymer.

[0079] [Table 3]

[0080] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: Optical FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent The solution of the polymer (PA-1) obtained in Synthesis Example 1 was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solid content of 3.5 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0081] 2. Fabrication of FFS-type LCD elements using the photoalignment method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side, and a glass substrate (referred to as the second substrate) without an electrode were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. This was followed by drying (post-baking) for 30 minutes in an oven at 230°C with the interior substituted with nitrogen, forming a coating film with an average thickness of 0.1 μm. The resulting coating film was irradiated with 1,000 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2 The coating film was then irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The irradiation dose was measured using an actinometer measuring at a wavelength of 254 nm. The photo-aligned coating film was then heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer edge of the surface bearing the liquid crystal alignment film. The substrates were then stacked and pressed together so that the projection directions of the polarization axes on the substrate surfaces during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove flow alignment during liquid crystal injection, the liquid crystal cell was heated to 120°C and then slowly cooled to room temperature. Polarizing plates were then attached to both outer surfaces of the substrates in the liquid crystal cell to obtain a liquid crystal display device. The above series of operations was also performed with a post-baking UV exposure dose of 100 to 10,000 J / m. 2 Three or more liquid crystal display elements with different amounts of ultraviolet light irradiation were manufactured by changing the exposure amount within the range of , and the liquid crystal display element with the exposure amount (optimum exposure amount) that showed the best alignment characteristics was used for the following evaluation.

[0082] 3. Evaluation of liquid crystal alignment (evaluation by retardation change rate) The LCD device manufactured in 2 above was 27,000 cd / m 2 The liquid crystal alignment was evaluated by the retardation change rate before and after backlight irradiation. First, the retardation of the liquid crystal display element manufactured in 2. above was measured using an Axoscan manufactured by Optoscience, and the retardation change rate α before and after backlight irradiation was calculated using the following formula (z-1). The smaller the change rate α, the less likely the liquid crystal alignment to deteriorate with backlight irradiation, and the better the liquid crystal alignment. A change rate α of 0.5% or less was rated "excellent (◎)," a change rate α of more than 0.5% and less than 1% was rated "good (○)," a change rate α of more than 1% and less than 2% was rated "fair (△)," and a change rate α of more than 2% was rated "poor (×)." α=Δθ / θ1 …(z-1) (In formula (z-1), Δθ represents the difference in retardation before and after irradiation, and θ1 represents the retardation value before irradiation.) As a result, the liquid crystal alignment property of this example was evaluated as "good (◯)".

[0083] 4. Evaluation of liquid crystal alignment after keystroke test (evaluation by number of bright spots) The liquid crystal display element manufactured in 2 above was evaluated for its liquid crystal alignment after a keystroke test. The evaluation was performed as follows. A silicone rubber pen 3R (manufactured by Touch Panel Laboratory Co., Ltd.) with a 3 mm radius tip was set on the keystroke section (solenoid type) of a keystroke tester (Touch Panel Laboratory Co., Ltd.), and the pen tip was positioned so that it was at the center of the liquid crystal display element. After 10,000 keystrokes with a load of 500 g and 10 Hz using the silicone rubber pen, the liquid crystal display element was observed under a microscope (100x magnification) to evaluate the liquid crystal alignment after the keystroke test. A case in which the number of bright spots was less than 50 was rated as "good (○)," a case in which the number was 50 to 100 was rated as "fair (△)," and a case in which the number was 100 or more was rated as "poor (×)." As a result, this example was rated as "good (○)."

[0084] 5. Evaluation of adhesion The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a glass substrate using a spinner, pre-baked for 2 minutes on a hot plate at 80°C, and then heated (post-baked) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average thickness of 0.10 μm. By repeating the same procedure, two glass substrates with coating films were produced. An ODF sealant (S-WB42, manufactured by Sekisui Chemical Co., Ltd.) was applied to the coating film of one of the glass substrates with a coating film formed thereon to a width of 1 mm, and the other glass substrate was then bonded together so that the coating film and ODF sealant were in contact. A metal halide lamp was then used to apply 30,000 J / m 2 After irradiating the film with light (equivalent to 365 nm), the film was heated in an oven at 120°C for 1 hour. The adhesion strength was then measured using a tension and compression tester (model number: SDWS-0201-100SL) manufactured by Imada Seisakusho, and the adhesion of the film to the substrate was evaluated. The evaluation was conducted when the adhesion strength was 175 N / cm 2 If it is above 125N / cm, it is considered "Good (○)" 2 More than 175N / cm 2 If it is less than 125N / cm, it is marked as "Fair (△)". 2 If the adhesive strength was less than 175 N / cm, it was rated as "poor (x)". 2 The adhesion was evaluated as "good (○)."

[0085] [Examples 2 to 13 and Comparative Examples 1 to 5] A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal display element was produced by a photoalignment method in the same manner as in Example 1, and the liquid crystal alignment property, alignment property after a keystroke test, and adhesion were evaluated. The results are shown in Table 4. In Examples 2, 4, 5, 8, 9, 11, and 13 and Comparative Examples 2 to 4, two types of polymers were used as the polymer component, and in Examples 6, 10, and 12, three types of polymers were used as the polymer component. In Table 4, the numerical values ​​for the polymers (Polymer 1, Polymer 2, and Polymer 3) represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0086] [Table 4]

[0087] As shown in Table 4, Examples 1 to 13, which used a liquid crystal alignment agent containing polymer [P], exhibited a good balance of liquid crystal alignment after backlight irradiation, liquid crystal alignment after a keystroke test, and adhesion, and showed favorable results, compared to Comparative Examples 1 to 5, which used a liquid crystal alignment agent not containing polymer [P]. Among them, Examples 1 to 9, 11, and 12 were all evaluated as "○" or "◎", and Examples 3 to 9 were particularly excellent, with the liquid crystal alignment being evaluated as "◎".

[0088] [Example 14: Rubbed FFS-type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 20 parts by mass of the polymer (PA-1) obtained in Synthesis Example 1 and a solution containing 80 parts by mass of the polymer (PA-10) obtained in Synthesis Example 10 were mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-19).

[0089] 2. Fabrication of FFS-type LCD elements using the rubbing method A first substrate and a second substrate similar to those in Example 1 were prepared. Next, a liquid crystal alignment agent (AL-19) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and then heated (pre-baked) on a hot plate at 110°C for 3 minutes. This was followed by drying (post-baking) for 30 minutes in a nitrogen-purged oven at 230°C, forming a coating film with an average film thickness of 0.08 μm. Next, the coating film surface was subjected to a rubbing treatment using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile indentation length of 0.3 mm. This was followed by ultrasonic cleaning in ultrapure water for 1 minute and then drying for 10 minutes in a clean oven at 100°C, yielding a pair of substrates with liquid crystal alignment films. Next, a pair of substrates with liquid crystal alignment films were screen-printed with an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. The substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled into the gap between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrates were heated to 120°C and then slowly cooled to room temperature to produce a liquid crystal cell. When stacking the pair of substrates, the rubbing directions of each substrate were set antiparallel. Polarizing plates were then attached to both outer surfaces of the substrates in the liquid crystal cell to obtain an FFS-mode liquid crystal display device.

[0090] 3. Evaluation The liquid crystal display element manufactured in 2. above was evaluated for liquid crystal alignment property and liquid crystal alignment property after a keystroke test in the same manner as in Example 1. In addition, using the liquid crystal alignment agent (AL-19) prepared in 1. above, the adhesion of the liquid crystal alignment film to the substrate was evaluated in the same manner as in Example 1. These results are shown in Table 5.

[0091] [Examples 15 to 21 and Comparative Example 6] A liquid crystal alignment agent was prepared in the same manner as in Example 14, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal display element was manufactured by the rubbing method in the same manner as in Example 14, and the liquid crystal alignment property, alignment property after a keystroke test, and adhesion were evaluated. The results are shown in Table 5. In Examples 15, 18, and 20, two types of polymers were used as the polymer component, and in Examples 16 and 21, three types of polymers were used as the polymer component. In Table 5, the numerical values ​​in the polymer column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0092] [Table 5]

[0093] As shown in Table 5, among Examples 14 to 21, which used a liquid crystal alignment agent containing polymer [P], Examples 14 to 18, 20, and 21 were all evaluated as "○" for liquid crystal alignment, liquid crystal alignment after the tapping test, and adhesion, demonstrating a good balance of various properties. Furthermore, Example 19 was evaluated as "△" for liquid crystal alignment after the tapping test, but the liquid crystal alignment and adhesion were evaluated as "○". In contrast, Comparative Example 6, which used a liquid crystal alignment agent not containing polymer [P], was evaluated as "×" for liquid crystal alignment and adhesion after the tapping test.

[0094] From the above results, it was revealed that a liquid crystal alignment agent containing polymer [P] can form a liquid crystal alignment film with excellent adhesion to the substrate, and can also produce liquid crystal elements with good liquid crystal alignment properties and alignment after keystroke tests.

Claims

1. A liquid crystal aligning agent comprising a polymer [P] having at least one selected from the group consisting of a partial structure represented by the following formula (1) (excluding the partial structure represented by the following formula R-DA-1, the partial structure represented by the following formula R-DA-2, the partial structure represented by the following formula R-DA-3, the partial structure represented by the following formula T-DA-1, and the partial structure represented by the following formula T-DA-2), a structural unit derived from a compound represented by the following formula (DA-2), a structural unit derived from a compound represented by the following formula (DA-3), and a structural unit derived from a compound represented by the following formula (DA-4). 【Chemical 1】 (In formula (1), Ar １ and Ar ２ are each independently a divalent aromatic ring group, and when the aromatic ring group has a substituent on the ring portion, the substituent is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom. １ and X ２ are each independently -NR ３ -, -O-, -S-, * １ -NR ３ -CO- or * １ -O-CO-. ３ is a hydrogen atom or a monovalent organic group. １ " is Ar １ or Ar ２ Represents a bond with R. １ and R ２ are each independently a divalent aliphatic hydrocarbon group. １ is -NR ４ -, -NR ４ -CO-* ２ , —CO—NR ４ -* ２ , -NR ４ -CO-NR ５ -* ２ , -NR ５ -CO-NR ４ -* ２ , -CH ２ -O-CO-* ２ , —CO—O—CH ２ -* ２ Or -O-. ４ is a monovalent organic group. ５ is a hydrogen atom or a monovalent organic group. ２ " is R ２ In the formula (1), all A １ When is -O-, X １ and X ２ are each independently -NR ３ -, * １ -NR ３ -CO- or * １ n is an integer of 1 to 3. When n is 2 or 3, multiple R １ are the same or different, and multiple A １ are the same or different. "*" represents a bond.) 【Chemistry 3】 (In the formula, "*" represents a bond.) 【Chemistry 4】

2. The polymer [P] is a compound represented by the following formula (2) (excluding compounds represented by the following formulas S-DA-1, S-DA-2, S-DA-3, U-DA-1, and U-DA-2), a compound represented by the formula (DA-2), a compound represented by the formula (DA-3), and a compound represented by the formula (DA-4). The liquid crystal aligning agent according to claim 1, having a structural unit derived from at least one selected from the group consisting of: 【Chemistry 2】 (In formula (2), Ar １ , Ar ２ , X １ , X ２ , R １ , R ２ , A １ and n have the same meanings as in formula (1) above. 【Chemistry 5】

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

4. The liquid crystal aligning agent according to any one of claims 1 to 3, further comprising a polymer [Q] different from the polymer [P].

5. The liquid crystal aligning agent according to claim 4 , wherein the polymer [Q] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

6. A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 5.

7. A method for producing a liquid crystal alignment film, comprising forming a coating film using the liquid crystal aligning agent according to any one of claims 1 to 5, and then subjecting the coating film to a light irradiation treatment to impart liquid crystal alignment ability.

8. A liquid crystal device comprising the liquid crystal alignment film according to claim 6 .

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