Liquid crystal alignment agent, liquid crystal alignment film and method for producing the same, liquid crystal element, and polymer

Abstract

To provide a liquid crystal alignment agent which can form a liquid crystal alignment membrane for making compatible both high-rubbing resistance and a favorable voltage holding characteristic, can suppress the generation of sublimation foreign matters when forming the liquid crystal alignment membrane by using an optical alignment method, and can obtain a liquid crystal element which is excellent in vibration resistance.SOLUTION: A polymer [P] selected from a group which is composed of a polyamic acid, polyamic acid ester and polyimide, and having a partial structure expressed by a formula (1) as a main chain is contained in a liquid crystal alignment agent. In the formula, R1 and R2 are a hydrogen atom or a monovalent organic group independently. X1 is a single-bond or divalent organic group. D 1 is a monovalent group which is replaced to a hydrogen atom by at least any of heat, light, an acid and a base. "*" expresses a bonding hand for bonding atoms constituting a polymer main chain.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a method for producing the same, and a liquid crystal element. and polymerization On the body Regarding. [Background technology]

[0002] Liquid crystal elements are widely used in various devices such as televisions, mobile devices, and various monitors. In liquid crystal elements, the alignment of liquid crystal molecules in a liquid crystal cell is controlled by a liquid crystal alignment film, which is an organic film formed on a substrate. Conventional methods for obtaining an organic film with liquid crystal alignment control power include a method of subjecting an organic film formed using a polymer composition to a rubbing treatment, a method of obliquely depositing silicon oxide, a method of forming a monomolecular film having a long-chain alkyl group, and a method of irradiating a photosensitive organic film with light (photoalignment method).

[0003] The rubbing method is commonly used because it is simple and provides good alignment of liquid crystal molecules. On the other hand, the photo-alignment method can impart uniform liquid crystal alignment to a photosensitive organic film while suppressing the generation of static electricity and dust, and also enables precise control of the liquid crystal alignment direction, so various studies have been conducted in recent years (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 176822 Summary of the Invention [Problem to be solved by the invention]

[0005] When liquid crystal alignment control using the rubbing method is adopted, it is necessary to prevent scraping of the liquid crystal alignment film during the rubbing process and to prevent degradation of display quality due to film scraping. On the other hand, there is often a trade-off between rubbing resistance and voltage holding ratio, and conventional liquid crystal alignment agents that have good resistance to scraping due to rubbing tend to have a low voltage holding ratio.

[0006] Furthermore, in the case of the photoalignment method, decomposition products generated by light irradiation of the organic film are usually removed by heating them in a heating furnace. In this decomposition product removal process, the decomposition products sublimated by heating tend to crystallize in the exhaust pipe of the heating furnace and adhere to the inside of the exhaust pipe as foreign matter (hereinafter also referred to as "sublimation products"). This requires cleaning the inside of the exhaust pipe to remove the sublimation foreign matter, which raises concerns about a decrease in the production efficiency of liquid crystal panels.

[0007] Furthermore, in recent years, there has been an increasing need for in-vehicle panels, and there is a demand for liquid crystal alignment films that suppress the occurrence of bright spots caused by loads such as vibrations when the liquid crystal panel is subjected to such loads.

[0008] The present invention has been made in view of the above circumstances, and one object of the present invention is to provide a liquid crystal alignment agent that can form a liquid crystal alignment film that can achieve both high rubbing resistance and good voltage retention characteristics, can suppress the generation of sublimated foreign matter when the liquid crystal alignment film is manufactured by a photoalignment method, and can obtain a liquid crystal element that has excellent vibration resistance. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by a liquid crystal aligning agent containing a polymer having a specific structure, thereby completing the present invention. Specifically, the present invention provides the following liquid crystal aligning agent, liquid crystal alignment film and manufacturing method thereof, liquid crystal element, polymer, and compound.

[0010] <1> A liquid crystal aligning agent comprising a polymer [P] selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and having a partial structure represented by the following formula (1) in its main chain: [ka] (In formula (1), R 1 and R 2 are each independently a hydrogen atom or a monovalent organic group. 1 is a single bond or a divalent organic group. 1 is a monovalent group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base. "*" represents a bond that bonds to an atom that constitutes the polymer main chain.

[0011] <2> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <3> the above <1> and a step of subjecting the coating film to a light irradiation treatment to impart liquid crystal aligning ability. <4> the above <2> A liquid crystal element comprising a liquid crystal alignment film.

[0012] A polymer having at least one selected from the group consisting of a partial structure represented by the following formula (2) and a partial structure represented by the following formula (3): [ka] (In formula (2) and formula (3), Y 1 is a tetravalent organic group. Y 2 R is a divalent group having a partial structure represented by the above formula (1). 3 and R 4 are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms.

[0013] A compound represented by the following formula (6): [ka] (In formula (6), A 1 and A 2are each independently a divalent aromatic ring group. 1 , B 2 and B 3 are each independently a single bond, -CO-NR 5 -, -NR 5 -CO-, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 -, -O-, -S-, a linear alkanediyl group having 1 to 12 carbon atoms, or any methylene group in a linear alkanediyl group having 2 to 12 carbon atoms is -CO-NR 5 -, -NR 5 -CO-, -NR 5 -, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 R is a divalent group in which R is replaced by -, -O-, or -S-. 5 and R 6 are each independently a hydrogen atom or a monovalent organic group. m is 0 or 1. R 1 , X 1 and R 2 is the same as the above formula (1). When m is 1, multiple R 1 , multiple X 1 and multiple R 2 are the same or different.) [Effects of the Invention]

[0014] The liquid crystal aligning agent of the present invention can form a liquid crystal alignment film that can achieve both high rubbing resistance and good voltage retention characteristics. Furthermore, when the liquid crystal alignment film is produced by a photoalignment method, the generation of sublimated foreign matter can be suppressed. Furthermore, a liquid crystal element with excellent vibration resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Liquid crystal alignment agent> The liquid crystal aligning agent of the present disclosure contains a polymer [P]. The liquid crystal aligning agent of the present disclosure may contain, together with the polymer [P], a component different from the polymer [P] (hereinafter also referred to as "other component"). The components contained in the liquid crystal aligning agent of the present disclosure and other components that are optionally blended as necessary will be described below.

[0016] <Polymer [P]> The polymer [P] is a polymer selected from the group consisting of polyamic acids, polyamic acid esters, and polyimides, and has a partial structure represented by the following formula (1) in its main chain. [ka] (In formula (1), R 1 and R 2 are each independently a hydrogen atom or a monovalent organic group. 1 is a single bond or a divalent organic group. 1 is a monovalent group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base. "*" represents a bond that bonds to an atom that constitutes the polymer main chain.

[0017] Here, in this specification, the "main chain" of a polymer refers to the "trunk" portion of the polymer, which is the longest chain of atoms. It is permissible for this "trunk" portion to contain a ring structure. Therefore, "having a partial structure represented by formula (1) in the main chain" means that this partial structure constitutes a part of the main chain. The "side chain" of a polymer refers to a portion branched from the "trunk" of the polymer.

[0018] In formula (1), R 1 and R 2 The monovalent organic group represented by the formula (I) includes a substituted or unsubstituted monovalent hydrocarbon group, and a substituted or unsubstituted monovalent hydrocarbon group in which any methylene group is -O-, -CO-, -CO-O-, -O-CO-, -NR 15 -, -CO-NR 15 -or-NR 15 -CO-(However, R 15is a hydrogen atom or a monovalent organic group).

[0019] Here, in this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed only of a chain structure. However, the chain hydrocarbon group may be saturated or unsaturated. "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, an alicyclic hydrocarbon group does not necessarily have to be composed only of an alicyclic hydrocarbon structure, and also includes groups that have a chain structure as part of it. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, an aromatic hydrocarbon group does not necessarily have to be composed only of an aromatic ring structure, and may contain a chain structure or an alicyclic hydrocarbon structure as part of it.

[0020] R 1 and R 2 Specific examples of the monovalent hydrocarbon group represented by the formula (I) include, as chain hydrocarbon groups, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, hexyl, octyl, decyl, vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl groups; as alicyclic hydrocarbon groups, cyclopentyl, cyclohexyl, and bicyclohexyl groups; and as aromatic hydrocarbon groups, phenyl, xylyl, tolyl, biphenyl, naphthyl, benzyl, phenylethyl, cyclohexylphenyl, phenylcyclohexyl, alkylcyclohexylphenyl, and alkylphenylcyclohexyl groups.

[0021] R 1 and R 2Specific examples of when R is a monovalent substituted hydrocarbon group include groups in which some or all of the hydrogen atoms of the monovalent hydrocarbon groups exemplified above have been substituted with one or more of halogen atoms, hydroxyl groups, thiol groups, -OP(=O)(OR)2, -COOR, carboxy groups, phosphate groups, -COSR, amide groups (-CO-NH2), nitro groups, organoxy groups, organosilyl groups, organothio groups, acyl groups, pyrrole groups, imidazole groups, pyrazole groups, and alkoxycarbonylamino groups (wherein each R is independently a monovalent hydrocarbon group).

[0022] R 1 If R has a bulky structure, the liquid crystal alignment property of the resulting liquid crystal element tends to be reduced. 1 is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, even more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.

[0023] R 2 represents the nitrogen-containing group (—NR 2 D 1 From the viewpoint of the reactivity of R), it is preferable that R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. 2 is preferably a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and even more preferably a hydrogen atom or a methyl group.

[0024] In equation (1), D 1 is a monovalent group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base, and its structure is not particularly limited. 1 is preferably a monovalent organic group that is at least thermally eliminated, and examples thereof include a carbamate-based leaving group, an amide-based leaving group, an imide-based leaving group, and a sulfonamide-based leaving group. 1 Further specific examples of include groups represented by the following formulae (D-1) to (D-5). [ka] (In formulas (D-1) to (D-5), Ar 1 R is a monovalent aromatic ring group having 6 to 10 carbon atoms. 13 is an alkyl group having 1 to 12 carbon atoms. 14 is a monovalent organic group. "*" represents a bond bonded to a nitrogen atom.

[0025] In formula (D-2), Ar 1 is a group in which one hydrogen atom has been removed from the ring portion of a substituted or unsubstituted aromatic ring having 6 to 10 carbon atoms. 1 Specific examples of the group represented by the formula (I) include a phenyl group, a methylphenyl group, and a naphthyl group.

[0026] In formula (D-4), R 13 Examples of the alkyl group having 1 to 12 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, and these may be linear or branched.

[0027] In formula (D-5), R 14 Examples of the monovalent organic group represented by the formula (I) include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms. 14 is preferably an aryl group having 6 to 10 carbon atoms, and more preferably an aromatic ring group such as a phenyl group or a naphthyl group. The groups represented by the above formulas (D-1) to (D-5) can be eliminated not only by heat but also by light.

[0028] D 1 Among these, carbamate-based leaving groups are preferred, and specifically, groups represented by the following formula (5) are preferred. [ka] (In formula (5), R 7is a monovalent organic group having 1 to 20 carbon atoms. "*" represents a bond.

[0029] In equation (5), R 7 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (I) include an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a 2,2,2-trichloroethyl group, and a 2-(trimethylsilyl)ethyl group.

[0030] Specific examples of carbamate-based leaving groups include a tert-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 2-nitrobenzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, a 1,1-dimethyl-2-cyanoethyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group (Fmoc group), an allyloxycarbonyl group, and a 2-(trimethylsilyl)ethoxycarbonyl group.

[0031] D 1 Among them, a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group is preferred because of its high thermal elimination property. 1 A tert-butoxycarbonyl group is particularly preferred in that the compound derived from the group can be sufficiently discharged outside the membrane as a gas.

[0032] In formula (1), X 1 is a single bond or a divalent organic group. 1 When is a divalent organic group, specific examples include groups represented by the following formula (7). [ka] (In formula (7), R 7 R is a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms. 8 is a divalent hydrocarbon group having 1 to 20 carbon atoms. 4 is a single bond or a divalent linking group. 4 If is a single bond, R7 is a single bond. 1 " represents a bond to the carbon atom in formula (1), and "*" 2 " represents a bond to the nitrogen atom in formula (1).

[0033] In equation (7), R 7 and R 8 The divalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms. 7 is bonded to the main chain of the polymer. From the viewpoint of improving the liquid crystal alignment property of the liquid crystal element, R 7 is preferably a single bond or an alkanediyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms, more preferably a single bond or an alkanediyl group having 1 to 10 carbon atoms, and even more preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms. 8 is preferably an alkanediyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms, more preferably an alkanediyl group having 1 to 10 carbon atoms, and even more preferably an alkanediyl group having 1 to 3 carbon atoms.

[0034] B 4 Specific examples of the divalent linking group represented by the formula (B4-1) include groups represented by the following formulas (B4-1) to (B4-13), but are not limited to these. [ka] (In formulas (B4-1) to (B4-13), R 9 and R 10 are each independently a hydrogen atom or a monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. 11 and R 12 are each independently a hydrogen atom, a monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or a monovalent leaving group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base. "*" represents a bond.

[0035] In formulas (B4-1) to (B4-3), R 9 and R10 Specific examples of the monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the formula: 1 and R 2 Examples of the monovalent substituted or unsubstituted hydrocarbon group represented by the following formula can be used: R 9 and R 10 When R has a bulky structure such as an aromatic ring or an alicyclic structure, the liquid crystal alignment property tends to decrease. 9 and R 10 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.

[0036] In formulas (B4-9) to (B4-13), R 11 and R 12 Specific examples of the monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the formula: 1 and R 2 Examples of the monovalent substituted or unsubstituted hydrocarbon group represented by the following formula can be used: R 11 and R 12 Specific examples of the monovalent leaving group represented by the formula: D 1 Examples of groups represented by the following formulae can be used.

[0037] From the viewpoint of improving the liquid crystal alignment property of the liquid crystal element and suppressing the occurrence of a tilt angle that affects color shift within the liquid crystal panel surface, X in formula (1) 1 Among these, is preferably a single bond, or an alkanediyl group, alkenyl group, or alkynyl group having 1 to 10 carbon atoms, more preferably a single bond or an alkanediyl group having 1 to 5 carbon atoms, still more preferably a single bond, a methylene group, or an ethylene group, and still more preferably a single bond.

[0038] The polymer [P] can be produced by polymerization using at least one monomer selected from the group consisting of tetracarboxylic acid derivatives having a partial structure represented by the above formula (1) in their main chains and diamines having a partial structure represented by the above formula (1) in their main chains. In terms of the high degree of freedom in the selection of monomers, the polymer [P] is preferably produced by polymerization using a diamine having a partial structure represented by the above formula (1) in its main chain (hereinafter also referred to as a "specific diamine"). Specifically, the polymer [P] preferably has at least one selected from the group consisting of a partial structure represented by the following formula (2) and a partial structure represented by the following formula (3). [ka] (In formula (2) and formula (3), Y 1 is a tetravalent organic group. Y 2 R is a divalent group having a partial structure represented by the above formula (1). 3 and R 4 are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms.

[0039] In formula (2) and formula (3), Y 1 is a tetravalent organic group derived from a tetracarboxylic acid derivative. In this specification, the term "tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0040] Y 1 As the tetracarboxylic acid derivative which gives Y, a compound known as a tetracarboxylic acid derivative which can be used in the production of polyamic acid, polyamic acid ester, and polyimide can be used. 1 is preferably a tetravalent group having a cyclobutane ring structure, and more preferably has at least one substituent on the ring portion of the cyclobutane ring. Examples of the substituent on the cyclobutane ring include a halogen atom, an alkyl group, a halogenated alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, a thioalkyl group, and "-COR30 " (R 30 is an alkyl group having 1 to 6 carbon atoms, a fluorine-containing alkyl group, an alkoxy group, or a fluorine-containing alkoxy group. The number of substituents is not particularly limited, but 1 to 4 is preferred, and 1 or 2 is more preferred.

[0041] Y 1 is a tetravalent group having a cyclobutane ring structure, Y 1 is preferably a group represented by the following formula (8). [ka] (In formula (8), R 31 , R 32 and R 33 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thioalkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or "-COR 30 " (R 30 R is an alkyl group having 1 to 6 carbon atoms, a fluorine-containing alkyl group, an alkoxy group, or a fluorine-containing alkoxy group. 34 is a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thioalkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or "-COR 30 " However, R 31 ~R 34 Adjacent groups may be bonded to each other to form a ring structure. "*" represents a bond.)

[0042] In the above formula (2), R 3 and R 4 Examples of the monovalent organic group having 1 to 6 carbon atoms represented by the formula (I) include a monovalent hydrocarbon group having 1 to 6 carbon atoms. From the viewpoint of ease of imidization by heating, R 3 and R 4 is preferably a hydrogen atom or a methyl group.

[0043] In the above formulas (2) and (3), Y 2 Y may have a partial structure represented by the above formula (1), and other structures are not particularly limited. From the viewpoint of reducing the generation of sublimation foreign matter when a photo-alignment treatment is performed and obtaining a liquid crystal device with few bright spots even when vibration is applied, 2 is preferably a divalent group represented by the following formula (4). [ka] (In formula (4), A 1 and A 2 are each independently a divalent aromatic ring group. 1 , B 2 and B 3 are each independently a single bond, -CO-NR 5 -, -NR 5 -CO-, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 -, -O-, -S-, a linear alkanediyl group having 1 to 12 carbon atoms, or any methylene group in a linear alkanediyl group having 2 to 12 carbon atoms is -CO-NR 5 -, -NR 5 -CO-, -NR 5 -, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 R is a divalent group in which R is replaced by -, -O-, or -S-. 5 and R 6 are each independently a hydrogen atom or a monovalent organic group. m is 0 or 1. R 1 , X 1 and R 2 is the same as the above formula (1). When m is 1, multiple R 1 , multiple X 1 and multiple R 2 are the same or different. "*" represents a bond.)

[0044] In equation (4), A 1 and A 2 The divalent aromatic ring group represented by the formula (I) is a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, and an anthracene ring; nitrogen-containing aromatic heterocycles such as a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and an imidazole ring; and sulfur-containing aromatic heterocycles such as a thiophene ring. When the aromatic ring has a substituent, examples of the substituent include an alkyl group having 1 to 6 carbon atoms.

[0045] From the viewpoint of improving the liquid crystal alignment and voltage retention characteristics, A 1 and A 2 A preferably has a ring structure selected from the group consisting of a benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and an imidazole ring. 1 and A 2 Preferred specific examples of the group include groups represented by the following formulae (a-1) to (a-11). [ka] (In the formula, "*" represents a bond.)

[0046] A: It is possible to form a liquid crystal alignment film with excellent liquid crystal alignment and voltage retention properties. 1 and A 2 Among the above, groups represented by formulae (a-1) to (a-6) are preferred, and groups represented by formula (a-1) or formula (a-6) are more preferred.

[0047] B 1 , B 2 and B 3Examples of the linear alkanediyl group having 1 to 12 carbon atoms represented by the formula (I) include a methylene group, a 1,2-ethylene group, a 1,3-propylene group, a 1,4-butylene group, a 1,5-pentylene group, a 1,6-hexylene group, a 1,9-nonylene group, a 1,12-dodecylene group, etc. Among these, from the viewpoint of achieving excellent liquid crystal alignment properties of a liquid crystal element while fully obtaining the effects of reducing the generation of sublimation foreign matter accompanying a photoalignment treatment and of making bright spots less likely to occur and degradation of display quality when a liquid crystal element is subjected to vibration, those having 1 to 6 carbon atoms are preferred, and those having 1 to 3 carbon atoms are more preferred.

[0048] B 1 , B 2 and B 3 In the formula (I), the group replacing any methylene group in the linear alkanediyl group having 2 to 12 carbon atoms is —CO—NR 5 -, -NR 5 -CO-, -NR 5 -, -CO-O-, -O-CO-, -O- or -S- is preferred, and -CO-NR 5 -, -NR 5 It is more preferably -CO-, -O- or -S-. When multiple methylene groups in a linear alkanediyl group having 2 to 12 carbon atoms are replaced, adjacent methylene groups are not replaced at the same time.

[0049] R 5 and R 6 Examples of the monovalent organic group represented by R include a monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, and a monovalent leaving group that is substituted with a hydrogen atom by at least one of heat, light, acid, and base. 5 and R 6 Specific examples of the monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the formula: 1 and R 2 Examples of the monovalent substituted or unsubstituted hydrocarbon group represented by the following formula can be used: R 5 and R 6 Specific examples of the monovalent leaving group represented by the formula: D 1From the viewpoint of improving the liquid crystal alignment property, R 5 and R 6 Among these, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a tert-butoxycarbonyl group is preferred.

[0050] B 1 , B 2 and B 3 In order to obtain the effects of preventing sublimation of foreign matter during photo-alignment treatment and preventing bright spots from occurring when the liquid crystal element is subjected to vibration, while also improving the liquid crystal alignment of the liquid crystal element, the compound is particularly preferably a linear alkanediyl group having 1 to 6 carbon atoms, or a linear alkanediyl group having 2 to 6 carbon atoms, in which any methylene group is -CO-NR 5 -, -NR 5 -CO-, -NR 5 -, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 From the above viewpoint, it is particularly preferred that the alkanediyl group is a linear alkanediyl group having 1 to 3 carbon atoms, or a linear alkanediyl group having 2 to 3 carbon atoms, in which any methylene groups are not adjacent to each other, and which is represented by -CO-NR 5 -, -NR 5 -CO-, -NR 5 -, -CO-O-, -O-CO-, -NR 5 -CO-NR 6 -, -NR 5 -CO-O-, -O-CO-NR 5 It is preferably a divalent group substituted with -, -O- or -S-.

[0051] B 1 , B 2 and B 3 Preferred specific examples of the group include groups represented by the following formulae (b-1) to (b-20). [ka]

[0052] m is 0 or 1, and is preferably 0 from the viewpoint of rubbing resistance. In equation (4), R 1 , R 2 , X 1 and D 1 The above explanations are applicable to specific examples and preferred examples.

[0053] In the polymer [P], the total content of the partial structure represented by formula (2) and the partial structure represented by formula (3) is preferably 3 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more. The content of the partial structures represented by formula (2) and formula (3) within the above range is advantageous in that it can achieve both rubbing resistance and voltage retention characteristics when liquid crystal alignment is controlled by rubbing treatment, it can reduce the generation of sublimated foreign matter when liquid crystal alignment is controlled by photoalignment, and it can provide a liquid crystal device with excellent vibration resistance. Furthermore, in the polymer [P], the total content of the partial structure represented by formula (2) and the partial structure represented by formula (3) may be 100 mol% or less, preferably 80 mol% or less, and more preferably 50 mol% or less.

[0054] The method for producing the polyamic acid, polyamic acid ester, and polyimide as the polymer [P] is not particularly limited, and they can be produced by appropriately combining standard methods in organic chemistry.

[0055] [Polyamic acid] The polyamic acid as the polymer [P] (hereinafter also referred to as "polyamic acid (P)") can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine.

[0056] (Tetracarboxylic acid dianhydride) Examples of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid (P) include aliphatic tetracarboxylic acid dianhydrides and aromatic tetracarboxylic acid dianhydrides. The aliphatic tetracarboxylic acid dianhydrides include chain tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides.

[0057] Specific examples of the chain tetracarboxylic dianhydride include butane tetracarboxylic dianhydride, etc. Specific examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutane tetracarboxylic 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, 3-oxabicyclo[3.2.1]octane-2,4-dione, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,3,5-tricarboxycyclopentylacetic dianhydride ... 6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid 2:3,5:6-dianhydride, 4,9-dioxatricyclo[5.3.1.0]octane-2,4,6,8-tetracarboxylic acid 2:3,5:6-dianhydride 2,6 ]undecane-3,5,8,10-tetraone, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, cyclopentanetetracarboxylic dianhydride, and the like.

[0058] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4'-biphthalic dianhydride. In addition to the above, the tetracarboxylic dianhydrides described in JP 2010-97188 A can be used as the tetracarboxylic dianhydride used in the synthesis of the polyamic acid (P). The tetracarboxylic dianhydrides used in the synthesis of the polyamic acid (P) can be used alone or in combination of two or more.

[0059] When imparting liquid crystal alignment ability to a coating film by photoalignment treatment, it is preferable to use a substituted cyclobutanetetracarboxylic dianhydride in synthesizing the polyamic acid (P), since the photoreactivity of the coating film can be increased in combination with a specific diamine. Specific examples of the substituted cyclobutanetetracarboxylic dianhydride include the compounds represented by the following formulas (t-1) to (t-6). [ka]

[0060] When a substituted cyclobutanetetracarboxylic dianhydride is used in synthesizing the polyamic acid (P), the proportion of the substituted cyclobutanetetracarboxylic dianhydride used is preferably 10 mol % or more, more preferably 30 mol % or more, and even more preferably 50 mol % or more, based on the total amount of the tetracarboxylic dianhydride used in the synthesis, from the viewpoint of sufficiently increasing the photoreactivity of the coating film.

[0061] (Diamine compounds) A specific diamine can be preferably used in synthesizing the polyamic acid (P). The specific diamine only needs to have the partial structure represented by the above formula (1), and other structures are not particularly limited. A preferred specific example of the specific diamine is a compound represented by the following formula (6): [ka] (In formula (6), R 1 , X 1 , R 2 , A 1 , A 2 , B 1 , B 2 , B 3 and m are defined as in formula (4) above.

[0062] A in the above formula (6) 1 , A 2 , B 1 , B 2 , B 3 , R 1 , R 2 Specific examples and preferred examples of X and D are the same as those described for formula (4). Specific examples of the specific diamine include compounds represented by the following formulas (d-1) to (d-28). In formula (d-14), n is an integer of 1 to 20. In the structural formulas, "Boc" represents a tert-butoxycarbonyl group, "Fmoc" represents a 9-fluorenylmethoxycarbonyl group, and "TMS" represents a trimethylsilyl group (the same applies hereinafter). The asymmetric carbons in the following formulas (d-1) to (d-25) do not specify a stereostructure, and may be either a single R-configuration or an S-configuration, or may be a mixture of R-configuration and S-configuration in any ratio. [ka] [ka] [ka]

[0063] Of these, the specific diamine is preferably a compound represented by each of formulas (d-1) to (d-21), more preferably a compound represented by each of formulas (d-1) to (d-12), still more preferably a compound represented by each of formulas (d-1) to (d-8), (d-20) and (d-21), and particularly preferably a compound represented by each of formulas (d-1), (d-7), (d-8), (d-20) and (d-21). The specific diamine may be used alone or in combination of two or more.

[0064] The specific diamine can be synthesized by appropriately combining standard methods in organic chemistry, such as synthesizing a dinitro intermediate having a nitro group instead of the primary amino group of a diamine having the partial structure represented by the above formula (1), and then amminating the nitro group of the obtained dinitro intermediate using an appropriate reduction system.

[0065] The method for synthesizing the dinitro intermediate can be appropriately selected depending on the target compound. For example, there can be mentioned a method of reacting a hydroxyl group-containing compound having the partial structure represented by the above formula (1) with a halogenated nitrobenzene, preferably in an organic solvent, if necessary, in the presence of a catalyst; a method of condensing an acid halide having the partial structure represented by the above formula (1) with an amino group-containing compound, preferably in an organic solvent, if necessary, in the presence of a catalyst; a method of condensing a carboxylic acid having the partial structure represented by the above formula (1) with an amino group-containing compound, preferably in an organic solvent, if necessary, in the presence of a catalyst;

[0066] The reduction reaction of the dinitro intermediate can be preferably carried out in an organic solvent using a catalyst (e.g., palladium-on-carbon, platinum oxide, zinc, iron, tin, nickel, etc.). Examples of the organic solvent used here include ethyl acetate, toluene, tetrahydrofuran, and alcohols. However, the synthesis procedure for the specific diamine is not limited to the above method.

[0067] The diamine compound used in the synthesis of the polyamic acid (P) may be the specific diamine alone, or the specific diamine may be used in combination with a diamine not having the partial structure represented by the above formula (1) (hereinafter also referred to as "other diamines").

[0068] Examples of other diamines include aliphatic diamines, aromatic diamines, diaminoorganosiloxanes, etc. Aliphatic diamines include chain diamines and alicyclic diamines.

[0069] Specific examples of other diamines include chain diamines such as m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and 1,3-bis(aminomethyl)cyclohexane; alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); Examples of aromatic diamines include dodecanoxydiaminobenzene, tetradecanoxydiaminobenzene, pentadecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostannyl diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1 ,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, N-(2,4-diaminophenyl)-4-(4-heptylcyclohexyl)benzamide, 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 a bond to the diaminophenyl group). 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. Directing group-containing diamines such as compounds represented by the formula: Paraphenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis(4-amino phenoxy)heptane, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, N,N-bis(4-aminophenyl)methylamine, N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, 4,4'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))dianiline, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoro Methyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzyl Zene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-piperazine, 3,5-diaminobenzoic acid, and compounds of the following formula (D-1): [ka] (In formula (D-1), R 41 and R 42 are each independently an alkanediyl group. 41 -COO-, -NR43 CO- or -NR 43 CONR 44 -R 43 and R 44 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group. n1 is an integer of 1 to 3. When n1 is 2 or 3, multiple X 41 are the same or different, and multiple R 42 are the same or different.) Compounds represented by the formula: Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the diamines described in JP-A-2010-97188 can also be used. As other diamines used in the synthesis of the polyamic acid (P), one type can be used alone, or two or more types can be appropriately selected and used.

[0070] In the above formula (E-1), "-X I -(R I -X II ) d The divalent group represented by "-" is preferably an alkanediyl group having 1 to 3 carbon atoms, *-O-, *-COO-, or *-O-C2H4-O- (wherein the bond marked with "*" is bonded to a diaminophenyl group). III The group represented by the formula (I) is preferably linear. The two amino groups in the diaminophenyl group are preferably in the 2,4-position or the 3,5-position relative to the other group.

[0071] Specific examples of the compound represented by the above formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). [ka]

[0072] Examples of the compound represented by the above formula (D-1) include compounds represented by the following formulas (D-1-1) to (D-1-5). [ka]

[0073] In synthesizing the polyamic acid (P), the proportion of the specific diamine used is preferably 3 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to the total amount of diamine compounds used in synthesizing the polyamic acid (P). A proportion of the specific diamine used within the above range is advantageous in that it can achieve both rubbing resistance and voltage retention characteristics when liquid crystal alignment is controlled by rubbing treatment, it can reduce the generation of sublimated foreign matter when liquid crystal alignment is controlled by photoalignment, and it can produce liquid crystal elements with excellent vibration resistance. Furthermore, in synthesizing the polyamic acid (P), the proportion of the specific diamine used may be 100 mol% or less, preferably 80 mol% or less, and more preferably 50 mol% or less, relative to the total amount of diamine compounds used in synthesizing the polyamic acid (P).

[0074] (Synthesis of polyamic acid) The polyamic acid (P) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier. The ratio of the tetracarboxylic dianhydride and the diamine compound used in the synthesis reaction of the polyamic acid (P) is preferably such that 0.2 to 2 equivalents, and more preferably 0.3 to 1.2 equivalents, of the acid anhydride group of the tetracarboxylic dianhydride are used per equivalent of the amino group of the diamine compound.

[0075] Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The proportion of the molecular weight modifier used is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compounds used.

[0076] 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., more preferably 0 to 100° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

[0077] Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Among these organic solvents, it is preferable to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (Group 1 organic solvents), or a mixture of one or more selected from Group 1 organic solvents with one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (Group 2 organic solvents). In the latter case, the proportion of the Group 2 organic solvent used is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total amount of the Group 1 organic solvents and the Group 2 organic solvents.

[0078] Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols, or a mixture of one or more of these with other organic solvents in the above-mentioned proportions. The amount (x) of the organic solvent used is preferably an amount such that the total amount (y) of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 50 mass% relative to the total amount (x+y) of the reaction solution.

[0079] In this manner, a reaction solution containing the polyamic acid (P) dissolved therein is obtained. This reaction solution may be used directly for the preparation of a liquid crystal aligning agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the preparation of a liquid crystal aligning agent, or the isolated polyamic acid (P) may be purified and then used for the preparation of a liquid crystal aligning agent. When the polyamic acid (P) is subjected to dehydration ring closure to form a polyimide, the reaction solution may be used directly for the dehydration ring closure reaction, or the polyamic acid (P) contained in the reaction solution may be isolated and then used for the dehydration ring closure reaction, or the isolated polyamic acid (P) may be purified and then used for the dehydration ring closure reaction. The isolation and purification of the polyamic acid (P) can be carried out according to known methods.

[0080] [Polyamic acid ester] The polyamic acid ester as the polymer [P] can be obtained, for example, by [I] a method of reacting the polyamic acid (P) obtained by the above synthesis reaction with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine compound, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound.

[0081] In this specification, "tetracarboxylic acid diester" means a compound in which two of the four carboxy groups in a tetracarboxylic acid are esterified and the remaining two are carboxy groups. "Tetracarboxylic acid diester dihalide" means a compound in which two of the four carboxy groups in a tetracarboxylic acid are esterified and the remaining two are halogenated.

[0082] Examples of the esterifying agent used in the method [I] include hydroxyl group-containing compounds, acetal compounds, halides, epoxy group-containing compounds, etc. Specific examples of these include hydroxyl group-containing compounds such as alcohols (e.g., methanol, ethanol, propanol, etc.), and phenols (e.g., phenol, cresol, etc.); acetal compounds such as N,N-dimethylformamide diethyl acetal, N,N-diethylformamide diethyl acetal; halides such as methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane, etc.; and epoxy group-containing compounds such as propylene oxide, etc.

[0083] The tetracarboxylic acid diester used in Method [II] can be obtained by ring-opening the tetracarboxylic acid dianhydride exemplified in the description of the synthesis of polyamic acid (P) using an alcohol such as methanol or ethanol. The tetracarboxylic acid derivative used in Method [II] may be a tetracarboxylic acid diester alone, or may be used in combination with a tetracarboxylic acid dianhydride. Regarding the diamine compound, the specific diamine exemplified in the synthesis of polyamic acid may be used alone, or may be used in combination with other diamines.

[0084] The reaction of method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. Examples of the organic solvent include those exemplified as those used in the synthesis of polyamic acid (P). Examples of the dehydration catalyst include 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, and phosphorus-based condensing agents. The reaction temperature is preferably −20 to 150° C., more preferably 0 to 100° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

[0085] The tetracarboxylic acid diester dihalide used in Method [III] can be obtained, for example, by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride. The tetracarboxylic acid derivative used in Method [III] may be the tetracarboxylic acid diester dihalide alone, or may be used in combination with a tetracarboxylic acid dianhydride. Regarding the diamine compound, the specific diamines exemplified in the description of the synthesis of the polyamic acid (P) may be used alone or in combination with other diamines.

[0086] The reaction in method [III] is preferably carried out in an organic solvent in the presence of a suitable base. Examples of the organic solvent include those exemplified as those used in the synthesis of polyamic acid (P). Examples of the base that can be preferably used include tertiary amines such as pyridine and triethylamine; and alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, and potassium. The reaction temperature is preferably −20 to 150° C., more preferably 0 to 100° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

[0087] The polyamic acid ester contained in the liquid crystal aligning agent 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 may be used for preparing the liquid crystal aligning agent as is, or the polyamic acid ester contained in the reaction solution may be isolated and then used for preparing the liquid crystal aligning agent, or the isolated polyamic acid ester may be purified and then used for preparing the liquid crystal aligning agent. The isolation and purification of the polyamic acid ester may be carried out according to a known method.

[0088] [Polyimide] The polyimide as the polymer [P] can be obtained, for example, by dehydrating and cyclizing the polyamic acid (P) synthesized as described above to form an imidized polymer.

[0089] The polyimide may be a fully imidized product in which all amic acid structures contained in its precursor polyamic acid 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 used in the reaction preferably has an imidization rate of 20% or more, more preferably 30 to 99%, and even more preferably 40 to 99%. This 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.

[0090] The dehydration ring-closure of the polyamic acid is preferably carried out by heating the polyamic acid, or by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closure catalyst to the solution, and optionally heating the solution.

[0091] In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid, the dehydrating agent can 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 mol per mol of the amic acid structure of the polyamic acid. The dehydration ring-closing catalyst can be, for example, a tertiary amine such as pyridine, collidine, lutidine, triethylamine, or 1-methylpiperidine. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol per mol of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include the organic solvents exemplified as those used in the synthesis of polyamic acid. The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, more preferably 10 to 150°C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

[0092] In this way, a reaction solution containing a polyimide is obtained. This reaction solution may be used directly for the preparation of a liquid crystal aligning agent, or may be used for the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, or may be used for the preparation of a liquid crystal aligning agent after isolating the polyimide, or may be used for the preparation of a liquid crystal aligning agent after purifying the isolated polyimide. These purification operations can be performed according to known methods. Alternatively, polyimide can also be obtained by imidizing a polyamic acid ester.

[0093] The polymer [P] obtained as described above preferably has a solution viscosity of 20 to 1,800 mPa·s, and more preferably 50 to 1,500 mPa·s, when made into a 15% by mass solution. The solution viscosity (mPa·s) of the polymer is a value measured at 25°C using an E-type rotational viscometer for a 15% by mass polymer solution prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0094] 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) of the polymer [P], expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 5 or less, more preferably 3.5 or less. Having the Mw and Mw / Mn of the polymer [P] within the above ranges ensures good alignment and stability of the liquid crystal display device.

[0095] <Other ingredients> The liquid crystal aligning agent of the present disclosure may contain components (other components) other than the polymer [P]. Examples of other components include a polymer not having the partial structure represented by the above formula (1) in its main chain (hereinafter also referred to as "other polymers"), a crosslinkable group-containing compound, a functional silane compound, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, an acid generator, a base generator, and a radical generator. The blending ratio of these components can be appropriately selected depending on each compound, as long as the effects of the present disclosure are not impaired.

[0096] (Other polymers) The other polymers are used for the purposes of suppressing a decrease in voltage holding ratio and improving liquid crystal alignment. The main skeleton of the other polymers is not particularly limited, but examples include polymers having a main skeleton of polyamic acid, polyimide, polyamic acid ester, polyorganosiloxane, polyester, cellulose derivative, polyacetal, or addition polymer. The addition polymer is a polymer containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond, such as a styrene-based polymer, a (meth)acrylic polymer, a maleimide-based polymer, or a styrene-maleimide-based copolymer. Of these, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and addition polymer.

[0097] In addition, when the liquid crystal alignment agent is used for photo-alignment treatment, the polymer [P] may contain a photosensitive polymer and the other polymer may contain a non-photosensitive polymer. Alternatively, the polymer [P] may contain a non-photosensitive polymer and the other polymer may contain a photosensitive polymer. Furthermore, both the polymer [P] and the other polymer may contain a photosensitive polymer.

[0098] When other polymers are contained in the liquid crystal aligning agent, the content ratio of the other polymers is preferably 1 to 95 mass %, more preferably 5 to 90 mass %, and even more preferably 15 to 80 mass %, relative to the total amount of polymers in the liquid crystal aligning agent.

[0099] (Crosslinkable group-containing compound) The crosslinkable group-containing compound is used for the purpose of further improving rubbing resistance and vibration resistance. Examples of the crosslinkable group contained in the crosslinkable group-containing compound include groups that can form a crosslinked structure by reacting with the same type of group or with a functional group contained in the polymer [P] to form a covalent bond, such as an epoxy group, a carboxy group, a cyclic carbonate group, a methylol group, or a maleimide group. The number of crosslinkable groups contained in the crosslinkable group-containing compound is preferably 2 or more, more preferably 3 or more, and even more preferably 3 to 8.

[0100] When the liquid crystal aligning agent contains a crosslinkable group-containing compound, the proportion of the crosslinkable group-containing compound is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the total amount of polymer components in the liquid crystal aligning agent. Furthermore, from the viewpoint of suppressing performance degradation due to the addition of an excessive amount, the proportion of the crosslinkable group-containing compound is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of polymer components in the liquid crystal aligning agent. The crosslinkable group-containing compound may be used alone or in combination of two or more.

[0101] <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.

[0102] Examples of the organic solvent to be used include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, and 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, etc. These can be used alone or in combination of two or more.

[0103] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent of 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 %. That is, the liquid crystal aligning agent is applied to the surface of a substrate as described below, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film. In this case, if the solid content concentration is 1 mass % or more, the coating film can have a sufficient thickness, and a good liquid crystal alignment film tends to be easily obtained. If the solid content concentration is 10 mass % or less, the coating film thickness does not become too large, and an increase in the viscosity of the liquid crystal aligning agent can be suppressed, tending to improve the coatability.

[0104] The particularly preferred range of solid content varies depending on the application of the liquid crystal aligning agent and the method used to apply the liquid crystal aligning agent to a substrate. For example, when applying a liquid crystal aligning agent for a liquid crystal display device to a substrate by a spinner method, the solid content (the ratio of the total mass of all components in the liquid crystal aligning agent other than the solvent to the total mass of the liquid crystal aligning agent) is particularly preferably in the range of 1.5 to 4.5 mass%. When using a printing method, the solid content is particularly preferably in the range of 3 to 9 mass%, thereby adjusting the solution viscosity to a range of 12 to 50 mPa·s. When using an inkjet method, the solid content is particularly preferably in the range of 1 to 5 mass%, thereby adjusting the solution viscosity to a range of 3 to 15 mPa·s. The temperature when preparing the liquid crystal aligning agent is preferably 10 to 50°C, more preferably 20 to 30°C. In addition, with regard to the liquid crystal aligning agent for the retardation film, from the viewpoint of the applicability of the liquid crystal aligning agent and the thickness of the coating film to be formed being appropriate, the solid content concentration of the liquid crystal aligning agent is preferably in the range of 0.2 to 10 mass %, more preferably in the range of 3 to 10 mass %.

[0105] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is formed 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 operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and various modes such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment) (including VA-MVA, VA-PVA, etc.), IPS (In-Plane Switching), FFS (Fringe Field Switching), OCB (Optically Compensated Bend), and PSA (Polymer Sustained Alignment) can be applied. 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.

[0106] (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. The substrate may be a transparent substrate made of glass such as float glass or soda glass, or plastic such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, or poly(alicyclic olefin). The transparent conductive film provided on one side of the substrate may be a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO2), or an ITO film made of indium oxide-tin oxide (In2O3-SnO2). When manufacturing a TN-, STN-, VA-, or PSA-type liquid crystal device, two substrates each having a patterned transparent conductive film are used. On the other hand, when manufacturing an IPS- or FFS-type liquid crystal device, one substrate has an electrode made of a transparent conductive film or metal film patterned into a comb-tooth shape, and another substrate has no electrode. The metal film may be a film made of a metal such as chromium. The liquid crystal alignment agent is preferably applied to the electrode-forming surface of the substrate by offset printing, spin coating, roll coating, or inkjet printing.

[0107] After applying the liquid crystal aligning agent, preheating (pre-baking) is preferably carried out to prevent 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, if necessary, a baking (post-baking) step is carried out to completely remove the solvent or thermally imidize the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 300°C, and the post-baking time is preferably 5 to 200 minutes. The film thus formed preferably has a thickness of 0.001 to 1 μm. After applying the liquid crystal aligning agent to the substrate, the organic solvent is removed to form a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film.

[0108] (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, resulting in a liquid crystal alignment film. Examples of alignment treatments include a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, and a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability. In particular, the liquid crystal aligning agent of the present disclosure is preferably used as a photo-alignment agent in which a coating film formed using the liquid crystal aligning agent is subjected to a photo-irradiation treatment to impart liquid crystal alignment ability. On the other hand, when producing a vertical alignment type (VA type) liquid crystal device, the coating film formed in step 1 can be used as a liquid crystal alignment film as is, or the coating film may be subjected to an alignment treatment. A liquid crystal alignment film suitable for a vertical alignment type liquid crystal device can also be preferably used for a PSA type liquid crystal device.

[0109] The light irradiation in the photo-alignment treatment 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 and post-bake steps. In the photo-alignment treatment, 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. Furthermore, 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 irradiating with unpolarized radiation, the irradiation direction is an oblique direction.

[0110] The light source used may be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, or a meta Examples of the radiation that can be used include an argon resonance lamp, a xenon lamp, and an excimer laser. The radiation dose is preferably 400 to 20,000 J / m 2 and more preferably 1,000 to 5,000 J / m2 The coating film may be irradiated with light while being heated in order to enhance the reactivity.

[0111] In producing a liquid crystal alignment film, the coating film that has been subjected to light irradiation treatment may be heated within a temperature range of 120°C or higher and 280°C or lower. Such a heat treatment is preferable in that it further improves the liquid crystal alignment (thermal reorientation) and results in a liquid crystal device with improved display quality. This heating may be post-baking, or may be a heat treatment that is performed separately from post-baking and after post-baking. In the heat treatment of the coating film that has been subjected to light irradiation treatment, the heating temperature is preferably 140°C or higher, more preferably 150°C to 250°C, from the viewpoint of promoting reorientation of molecular chains by heating. The heating time is preferably 5 to 200 minutes, more preferably 10 to 60 minutes.

[0112] The production of a liquid crystal alignment film may further include a step of contacting the light-irradiated coating film with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. Examples of water-soluble organic solvents include methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone. Among these, water, isopropanol, and mixtures thereof are preferred as the solvent used in this step. Examples of methods for contacting the coating film with the solvent include, but are not limited to, spraying, showering, immersion, and puddling. The contact time between the coating film and the solvent is not particularly limited, but is, for example, 5 seconds to 15 minutes. After contact with the solvent, the coating film may be subjected to a heat treatment.

[0113] (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 fabricated by placing a liquid crystal between the two substrates facing each other. Examples of methods for fabricating a liquid crystal cell include: (1) placing the two substrates facing each other with a spacer 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 substrate surfaces and the cell gap defined by the sealant, and then sealing the injection hole; and (2) applying a sealant to a predetermined location on one substrate with a liquid crystal alignment film, dropping liquid crystal at several predetermined locations on the liquid crystal alignment film, and then bonding the other substrate so that the liquid crystal alignment film faces each other, and spreading the liquid crystal over the entire surface of the substrate (ODF method). The fabricated liquid crystal cell is preferably further heated to a temperature at which the liquid crystal used assumes an isotropic phase and then slowly cooled to room temperature to remove the flow alignment that occurred during liquid crystal filling.

[0114] Examples of sealing agents that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of spacers that can be used include photospacers and bead spacers. Examples of liquid crystals that can be used include nematic liquid crystals and smectic liquid crystals. Among these, nematic liquid crystals are preferred, and examples that can be used include Schiff-based liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenylcyclohexane liquid crystals, pyrimidine liquid crystals, dioxane liquid crystals, bicyclooctane liquid crystals, and cubane liquid crystals. Furthermore, cholesteric liquid crystals, chiral agents, ferroelectric liquid crystals, and the like may be added to these liquid crystals.

[0115] 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 liquid crystal element, the proportion of the polymerizable compound used is, for example, 0.01 to 3 parts by mass, preferably 0.05 to 1 part by mass, per 100 parts by mass of the total liquid crystal.

[0116] Next, if necessary, a polarizing plate is 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, or a polarizing plate made of the H film itself. This produces a liquid crystal device.

[0117] The liquid crystal element of the present disclosure can be effectively applied to various uses, for example, various display devices such as watches, 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 films, etc. Furthermore, a liquid crystal element formed using the liquid crystal aligning agent of the present disclosure can also be applied to a retardation film.

[0118] According to the present disclosure described above, the following means are provided. [Means 1] A liquid crystal aligning agent containing a polymer [P] selected from the group consisting of polyamic acid, polyamic acid ester and polyimide, and having a partial structure represented by the above formula (1) in the main chain. [Means 2] The liquid crystal aligning agent according to [Means 1], wherein the polymer [P] has at least one selected from the group consisting of a partial structure represented by the above formula (2) and a partial structure represented by the above formula (3). [Means 3] The Y 2 is a divalent group represented by the above formula (4), [Means 4] Said X 1 The liquid crystal aligning agent according to any one of [Means 1] to [Means 3], wherein is a single bond. [Means 5] The R 1 The liquid crystal aligning agent according to any one of [Means 1] to [Means 4], wherein is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. [Means 6] The above D 1 The liquid crystal aligning agent according to any one of [Means 1] to [Means 5], wherein is a group represented by the above formula (5). [Means 7] The liquid crystal aligning agent according to any one of [Means 1] to [Means 6], further comprising a polymer not having the partial structure represented by the above formula (1) in the main chain. [Means 8] A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of [Means 1] to [Means 7]. [Means 9] A method for producing a liquid crystal alignment film, comprising: a step of forming a coating film using the liquid crystal aligning agent according to any one of [Means 1] to [Means 7]; and a step of subjecting the coating film to a light irradiation treatment to impart liquid crystal alignment ability. [Means 10] The method for producing a liquid crystal alignment film according to [Means 9], further comprising a step of heating the coating film that has been subjected to the light irradiation treatment at a temperature of 120°C or higher and 280°C or lower. [Means 11] A liquid crystal device comprising the liquid crystal alignment film according to [Means 8]. [Means 12] A polymer having at least one selected from the group consisting of a partial structure represented by the above formula (2) and a partial structure represented by the above formula (3). [Means 13] A compound represented by the above formula (6). [Example]

[0119] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0120] The structures and abbreviations of the main compounds used in the following examples are as follows: As compound (DA-5), a diamine with n=7 was used.

[0121] (Tetracarboxylic acid dianhydride) TA-1; Pyromellitic dianhydride TA-2; 1,2,3,4-Cyclobutanetetracarboxylic dianhydride TA-3; 2,3,5-tricarboxycyclopentylacetic dianhydride TA-4; (1R,2R,3S,4S)-1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic acid dianhydride [ka]

[0122] (specific diamine) [ka]

[0123] (Other diamines) [ka]

[0124] (Other monomers) [ka]

[0125] (additives) [ka]

[0126] (solvent) NMP; N-methyl-2-pyrrolidone BC: Butyl cellosolve GBL; gamma butyrolactone DMF; N,N-dimethylformamide EtOH; ethanol DCM; dichloromethane

[0127] The imidization ratio of the polyimide, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of the styrene-maleimide copolymer were measured by the following methods. [Imidization rate of polyimide] A solution containing polyimide 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 reference substance. 1 H-NMR was measured. 1 The imidization rate was calculated from the H-NMR spectrum using the following formula (EX-1). Imidization rate (%) = (1 - ((A1 / A2) x α)) x 100 ... (EX-1) (In formula (EX-1), A1 is the peak area derived from the proton of the NH group appearing at a chemical shift of around 10 ppm, A2 is the peak area derived from 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).) [Weight average molecular weight (Mw) and number average molecular weight (Mn)] Mw and Mn are values ​​calculated as polystyrene measured by GPC under the following conditions. Column: TSKgel GRCXLII, manufactured by Tosoh Corporation Solvent: tetrahydrofuran Temperature: 40℃ Pressure: 68kgf / cm 2

[0128] <Synthesis of Compounds> Compounds (DA-1) to (DA-9) were synthesized in the following synthesis examples. The compounds shown below can be obtained by combining known organic synthesis reactions.

[0129] [Synthesis Example 1: Synthesis of Compound (DA-1)] N-(tert-butoxycarbonyl)-4-nitro-D-phenylalanine (0.20 mol), 4-nitrobenzylamine hydrochloride (0.20 mol), and DMF (200 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube. 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.22 mol) was added in an ice bath and stirred at room temperature for 6 hours. After the reaction was completed, water (200 mL) was added to the reaction solution and stirred, and the suspension was filtered. The resulting precipitate was stirred in 100 mL of water, washed, and then vacuum dried to obtain the compound represented by the following formula (DA-1-a) (yield 89%). Next, (DA-1-a) (10.0 mmol), palladium-supported carbon (palladium 5% / carbon 95%) (0.16 g), and ethanol (30 mL) were placed in a 100 mL autoclave, hydrogen gas was blown in until the pressure reached 0.4 MPa, and the mixture was stirred at 50°C for 12 hours. After the reaction was completed, the reaction solution was filtered through Celite and concentrated under reduced pressure. The resulting precipitate was washed with ethanol and dried under vacuum to obtain the diamine represented by the following formula (DA-1) (yield 72%). [ka]

[0130] [Synthesis Example 2: Synthesis of Compound (DA-2)] 2-Amino-1,3-propanediol (0.30 mol), di-tert-butyl dicarbonate (0.33 mol), and DCM (200 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at room temperature for 12 hours. After completion of the reaction, 1N hydrochloric acid (200 mL) was added to the reaction solution, and the mixture was separated. The resulting organic layer was separated with water (200 mL), and the solvent was evaporated to obtain a compound represented by the following formula (DA-2-a) (yield 67%). Next, (DA-2-a) (0.15 mol), 2-fluoro-5-nitropyridine (0.30 mol), potassium carbonate (0.30 mol), and DMF were added to a three-neck flask equipped with a nitrogen inlet tube and stirred at 60°C for 4 hours. After the reaction was completed, water (200 mL) was added to the reaction solution and stirred, and the suspension was filtered. The resulting precipitate was stirred in 100 mL of water, washed, and then vacuum dried to obtain a compound represented by the following formula (DA-2-b) (yield 78%). Next, (DA-2-b) (30.0 mmol), palladium-supported carbon (palladium 5% / carbon 95%) (0.30 g), and ethanol (60 mL) were placed in a 100 mL autoclave, hydrogen gas was blown in until the pressure reached 0.4 MPa, and the mixture was stirred at 50°C for 12 hours. After the reaction was completed, the reaction solution was filtered through Celite and concentrated under reduced pressure. The resulting precipitate was washed with ethanol and dried under vacuum to obtain the diamine represented by the following formula (DA-2) (yield 72%). [ka]

[0131] [Synthesis Example 3: Synthesis of Compound (DA-3)] Compound (DA-3) was synthesized according to the following scheme: Protection of the amino group was carried out in the same manner as in Synthesis Example 2, and the subsequent condensation reaction and reduction reaction of the nitro group were carried out in the same manner as in Synthesis Example 1. [ka]

[0132] [Synthesis Example 4: Synthesis of Compound (DA-4)] Compound (DA-4) was synthesized according to the following scheme. 2-Amino-1,3-propanediol (0.30 mol) and DMF (200 mL) were added to a three-neck flask equipped with a nitrogen inlet tube and cooled to 0°C. Sodium hydride (0.75 mol, 60% in oil) was then added portionwise. 4-Fluoronitrobenzene (0.60 mol) was then added dropwise portionwise and stirred at room temperature for 5 hours. After the reaction was complete, water (200 mL) was added to the reaction solution, followed by stirring. The suspension was filtered. The resulting precipitate was stirred in 100 mL of water, washed, and then vacuum-dried to obtain a compound represented by the following formula (DA-4-a) (yield: 65%). The subsequent condensation reaction was carried out as in Synthesis Example 1, the amide group protection reaction was carried out as in Synthesis Example 2, and the nitro group reduction reaction was carried out as in Synthesis Example 1. [ka]

[0133] [Synthesis Example 5: Synthesis of Compound (DA-5)] Compound (DA-5) was synthesized according to the following scheme. [ka]

[0134] [Synthesis Example 6: Synthesis of Compound (DA-6)] Compound (DA-6) was synthesized according to the following scheme. [ka]

[0135] [Synthesis Example 7: Synthesis of Compound (DA-7)] Compound (DA-7) was synthesized according to the following scheme. [ka]

[0136] [Synthesis Example 8: Synthesis of Compound (DA-8)] Compound (DA-8) was synthesized according to the following scheme: Protection of the amino group was carried out in the same manner as in Synthesis Example 2, and reduction of the nitro group was carried out in the same manner as in Synthesis Example 1. [ka]

[0137] [Synthesis Example 9: Synthesis of Compound (DA-9)] Compound (DA-9) was synthesized according to the following scheme: The condensation reaction and the reduction reaction of the nitro group were carried out in the same manner as in Synthesis Example 1. [ka]

[0138] <Polymer synthesis> [Synthesis Example 10] Compound (DA-1) was dissolved in NMP as a diamine compound, and 0.95 equivalents of tetracarboxylic dianhydride (TA-1) relative to the diamine compound was added. The reaction was carried out at room temperature for 6 hours to obtain a 15% by mass solution of polyamic acid (polymer (PA-1)).

[0139] [Synthesis Examples 11 to 35] Polyamic acids (polymers (PA-2) to (PA-26)) were obtained in the same manner as in Synthesis Example 10, except that the types and amounts of tetracarboxylic dianhydrides and diamine compounds used in the reaction were changed as shown in Table 1 below. In Table 1, the numerical values ​​for the dianhydrides indicate the proportion of each compound used relative to 100 parts by mole of the total amount of tetracarboxylic dianhydrides used in the synthesis of the polymers (polyamic acid, polyimide). The numerical values ​​for the diamine compounds indicate the proportion of each compound used relative to 100 parts by mole of the total amount of diamine compounds used in the synthesis of the polymers (polyamic acid, polyimide).

[0140] [Synthesis Example 36] 80 moles of compound (DA-1) and 20 moles of compound (DB-6) were dissolved in NMP as diamine compounds, and 0.95 equivalents of tetracarboxylic dianhydride (TA-4) relative to the diamine compounds were added. The reaction was carried out at room temperature for 6 hours to obtain a polyamic acid solution. To the resulting solution, 0.8 equivalents of 1-methylpiperidine and acetic anhydride relative to the carboxy groups of the polyamic acid were added, and the mixture was heated and stirred at 60°C for 3 hours. The resulting solution was repeatedly concentrated under reduced pressure and diluted with NMP to obtain a 15% by mass solution of polyimide (polymer (PI-1)). The imidization rate of polymer (PI-1) was 80%.

[0141] [Synthesis Examples 37 to 58] Polyimides (polymers (PI-2) to (PI-23)) were obtained in the same manner as in Synthesis Example 36, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used in the reaction were changed as shown in Table 1 below.

[0142] [Table 1]

[0143] <Synthesis of addition polymer> [Synthesis Example 59] Under nitrogen, a 100 mL two-neck flask was charged with 10 mol parts of compound (M-1) per 100 parts by mass of polymerization monomer, 45 mol parts of compound (M-2), and 45 mol parts of compound (M-3), 3 mol parts of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 50 mL of N-methyl-2-pyrrolidone (NMP) as a solvent, and polymerized at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-1)). The weight-average molecular weight (Mw) measured by GPC (reduced to polystyrene equivalent) was 65,300, and the molecular weight distribution (Mw / Mn) was 4.11.

[0144] [Synthesis Example 60] Under nitrogen, a 100 mL two-neck flask was charged with the following polymerization monomers: 10 mol parts (per 100 parts by mass) of compound (M-4), 10 mol parts (M-5), 30 mol parts (M-6), 10 mol parts (M-7), 20 mol parts (M-8), and 20 mol parts (M-9), 3 mol parts (2,2'-azobis(2,4-dimethylvaleronitrile)) as a radical polymerization initiator, and 50 mL of tetrahydrofuran as a solvent. Polymerization was carried out at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-2)). The weight-average molecular weight (Mw) measured by GPC (converted to polystyrene) was 82,200, and the molecular weight distribution (Mw / Mn) was 4.71.

[0145] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 1: FFS-type liquid crystal display element by rubbing alignment method] (1) Preparation of liquid crystal alignment agent NMP and BC were added to the solution containing the polymer (PA-1) obtained in Synthesis Example 10 to prepare a solution with a solvent composition of NMP:BC = 80:20 (mass ratio) and a solid content concentration of 4.0 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (R-1).

[0146] (2) Formation of liquid crystal alignment film by rubbing alignment method The liquid crystal alignment agent (R-1) prepared in (1) above was applied to a glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side, and a counter glass substrate without an electrode, using a spinner. The substrate was then dried on a hot plate at 80°C for 1 minute, and then dried in a nitrogen-purged oven at 230°C for 30 minutes to form a coating film with an average thickness of 0.1 μm. The surface of this coating film was rubbed using a rubbing machine equipped with a roll wrapped around a nylon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 25 mm / sec, and a pile indentation length of 0.4 mm. The coating film subjected to the rubbed alignment treatment was ultrasonically cleaned in ultrapure water for 1 minute and then dried in an oven at 100°C for 10 minutes to form a liquid crystal alignment film.

[0147] (3) Manufacture of liquid crystal display elements A pair of substrates bearing the liquid crystal alignment film prepared in (2) above were screen-printed with an epoxy resin adhesive containing 5.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the alignment film. The substrates were then stacked and pressed together so that the polarization axes projected antiparallel to the substrate surface during light irradiation. The adhesive was then thermally cured at 150°C for 1 hour. Next, nematic liquid crystal (MLC-6608, manufactured by Merck) was filled 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. Polarizers were then attached to both outer surfaces of the substrates to produce an FFS-mode liquid crystal display device.

[0148] (4) Evaluation of rubbing resistance (evaluation based on the amount of foreign matter) The liquid crystal alignment agent (R-1) prepared in (1) above was applied to the transparent electrode surface of a glass substrate with an ITO film. The coating was then dried on a hot plate at 80°C for 1 minute, followed by drying in a nitrogen-purged oven at 230°C for 30 minutes to form a coating with an average thickness of 0.1 μm. The coating surface was rubbed 20 times using a rubbing machine equipped with a roll wrapped in cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 25 mm / sec, and a pile depth of 0.4 mm to obtain a substrate for evaluating the amount of foreign matter. The resulting substrate for evaluating the amount of foreign matter was observed with an optical microscope, and the number of foreign matter particles within a 500 μm x 500 μm area was counted. A sample with fewer than 5 foreign matter particles within a 500 μm x 500 μm area was rated "excellent," 5 to 10 foreign matter particles was rated "good," and 10 or more foreign matter particles was rated "poor." As a result, no foreign matter was found in this example, and it was rated as "excellent."

[0149] (5) Evaluation of voltage holding ratio For the FFS-mode liquid crystal display element manufactured in (3) above, a voltage of 5 V was applied at 23°C for 60 microseconds over a span of 167 milliseconds, and then the voltage holding ratio (VHR) was measured 1,000 milliseconds after the voltage was removed. A voltage holding ratio of 99.8% or more was rated "excellent," 98.0% or more but less than 99.8% was rated "good," and less than 98.0% was rated "poor." The result in this example was "excellent." The measuring device used was a VHR-1 manufactured by Toyo Corporation (the same applies to the evaluation of voltage holding ratio below).

[0150] (6) Bright spot evaluation after vibration test A 3 kg weight was attached to the FFS-type liquid crystal display element manufactured in (3) above, and vibration at 200 Hz was applied for 1 hour using a vibration tester. The FFS-type liquid crystal display element was observed under an optical microscope, and the number of bright spots within a 500 μm × 500 μm area was counted. A bright spot count of less than 5 within a 500 μm × 500 μm area was rated "excellent," a bright spot count of 5 to 10 was rated "good," and a bright spot count of 10 or more was rated "poor." As a result, no bright spots were observed in this example, and the evaluation was "excellent." The vibration tester used was the m030 / MA1-CE manufactured by IMV Corporation (the same applies to the bright spot evaluation after the vibration test below).

[0151] [Examples 2, 6 to 17, 20, and 23 and Comparative Examples 1, 2, and 6 to 10] In Example 1, a liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by the rubbing alignment method in the same manner as in Example 1, except that the polymer and solvent contained in the liquid crystal alignment agent were changed as shown in Table 2. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 2. In Table 2, the numerical values ​​for the solvents indicate the blending ratio of each compound relative to 100 parts by mass of the total amount of the solvent used to prepare the liquid crystal alignment agent.

[0152] [Examples 3, 18, 19, 21, 22 and Comparative Example 3] In Example 1, a liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a rubbing alignment method in the same manner as in Example 1, except that the polymer contained in the liquid crystal alignment agent in Example 1 was changed as shown in Table 2. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 2. In Examples 3, 18, 19, 21, 23 and Comparative Example 3, two types of polymers (polymer 1 and polymer 2) were contained in the liquid crystal alignment agent at a blending ratio of polymer 1:polymer 2 = 40:60 (mass ratio converted to solid content).

[0153] [Examples 4 and 5 and Comparative Examples 4 and 5] In Example 1, the liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by the rubbing alignment method in the same manner as in Example 1, except that the polymer contained in the liquid crystal alignment agent in Example 1 was changed as shown in Table 2 and the additives shown in Table 2 were added. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 2. In Examples 4 and 5 and Comparative Examples 4 and 5, the additive (AD-1 or AD-2) was contained in the liquid crystal alignment agent at a blending ratio of polymer 1:additive = 90:10 (mass ratio converted to solid content).

[0154] [Table 2]

[0155] [Example 24: FFS-type liquid crystal display device using photoalignment method] (1) Preparation of liquid crystal alignment agent NMP and BC were added to the solution containing the polymer (PI-1) obtained in Synthesis Example 36 to prepare a solution with a solvent composition of NMP:BC = 80:20 (mass ratio) and a solid content concentration of 4.0 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (R-24).

[0156] (2) Formation of liquid crystal alignment film by photoalignment method The liquid crystal alignment agent (R-24) prepared in (1) above was applied to a glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side thereof, and to an opposing glass substrate having no electrode, using a spinner to a film thickness of 0.1 μm, and then dried (prebaked) on a hot plate at 80°C for 1 minute to form a coating film. The surface of this coating film was irradiated with 400 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2 The photo-alignment treatment was performed by irradiating the coating film from the normal direction of the substrate. The photo-alignment treatment was performed by heating the coating film in a nitrogen-substituted oven at 230°C for 30 minutes (post-baking) to form a liquid crystal alignment film.

[0157] (3) Manufacture of liquid crystal display elements A pair of substrates bearing the liquid crystal alignment film prepared in (2) above were screen-printed with an epoxy resin adhesive containing 5.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the alignment film. The substrates were then stacked and pressed together so that the polarization axes projected antiparallel to the substrate surface during light irradiation. The adhesive was then thermally cured at 150°C for 1 hour. Next, nematic liquid crystal (MLC-6608, manufactured by Merck) was filled 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. Polarizers were then attached to both outer surfaces of the substrates to produce an FFS-mode liquid crystal display device.

[0158] (4) Evaluation of sublimation contaminants The liquid crystal alignment agent (R-24) prepared in (1) above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner and dried on a hot plate at 80°C for 1 minute. Thereafter, the surface of this coating was irradiated with linearly polarized ultraviolet light containing a 254 nm emission line (exposure dose: 400 J / m) using an Hg-Xe lamp. 2 ) from the normal direction of the substrate to perform a photo-alignment treatment. A glass petri dish was placed over the entire substrate, and the substrate was heated for 30 minutes in an oven at 230°C with the interior replaced with nitrogen. After removing from the oven, the substrate was left at room temperature for 30 minutes with the petri dish still covered. The foreign matter on the petri dish was observed under an optical microscope, and the number of foreign matter particles within a 500 μm x 500 μm area was counted. A number of less than 10 foreign matter particles within a 500 μm x 500 μm area was rated as "excellent," 10 to 20 foreign matter particles was rated as "good," and 20 or more foreign matter particles was rated as "poor." As a result, no foreign matter was found in this example, and the evaluation was "excellent."

[0159] (5) Evaluation of voltage holding ratio For the FFS-type liquid crystal display element manufactured in (3) above, a voltage of 5 V was applied at 23°C for 60 microseconds over a span of 167 milliseconds, and then the voltage holding ratio (VHR) was measured 1,000 milliseconds after the voltage was removed. A voltage holding ratio of 99.8% or more was rated "excellent," 98.0% or more but less than 99.8% was rated "good," and less than 98.0% was rated "poor." As a result, in this example, the result was "excellent."

[0160] (6) Bright spot evaluation after vibration test A 3 kg weight was attached to the FFS-type liquid crystal display element manufactured in (3) above, and vibrations of 200 Hz were applied for 1 hour using a vibration tester. The FFS-type liquid crystal display element was observed under an optical microscope, and the number of bright spots within a 500 μm × 500 μm area was counted. A value of less than 5 bright spots within a 500 μm × 500 μm area was rated "excellent," a value of 5 to 10 bright spots was rated "good," and a value of 10 or more bright spots was rated "poor." As a result, no bright spots were observed in this example, and the result was an "excellent" rating.

[0161] [Examples 25, 29 to 40 and Comparative Examples 11, 12, 16 to 20] In Example 24, a liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 24, except that the polymer and solvent contained in the liquid crystal alignment agent were changed as shown in Table 3. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 3. In Table 3, the numerical values ​​for the solvents indicate the blending ratio of each compound relative to 100 parts by mass of the total amount of the solvent used to prepare the liquid crystal alignment agent.

[0162] [Examples 26, 41 and Comparative Example 13] In Example 24, a liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 24, except that the polymer contained in the liquid crystal alignment agent in Example 24 was changed as shown in Table 3. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 3. In Examples 26, 41 and Comparative Example 13, two types of polymers (polymer 1 and polymer 2) were contained in the liquid crystal alignment agent at a blending ratio of polymer 1:polymer 2 = 40:60 (mass ratio converted to solid content).

[0163] [Examples 27 and 28 and Comparative Examples 14 and 15] In Example 24, the liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 24, except that the polymer contained in the liquid crystal alignment agent was changed as shown in Table 3 and the additives shown in Table 3 were added. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 3. In Examples 27 and 28 and Comparative Examples 14 and 15, the additive (AD-1 or AD-2) was contained in the liquid crystal alignment agent at a blending ratio of polymer 1:additive = 90:10 (mass ratio converted to solid content).

[0164] [Example 42] In Example 24, the polymer contained in the liquid crystal alignment agent was changed as shown in Table 3, and after pre-baking, the liquid crystal alignment agent was dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C, followed by photo-alignment treatment by ultraviolet irradiation, and then heat treatment for 30 minutes in a clean oven at 230°C. The liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by the photo-alignment method. FFS-type liquid crystal display elements and liquid crystal cells were manufactured and various evaluations were performed. The evaluation results are shown in Table 3. In Example 42, two types of polymers (polymer 1 and polymer 2) were contained in the liquid crystal alignment agent at a blending ratio of polymer 1:polymer 2 = 40:60 (mass ratio converted to solid content).

[0165] [Table 3]

[0166] [Example 43: Optical vertical liquid crystal display element] (1) Preparation of liquid crystal alignment agent To a solution containing the polymer (PA-21) obtained in Synthesis Example 30, the polymer (MI-1) obtained in Synthesis Example 59 was added so that the polymer (MI-1) was 10 parts by mass per 100 parts by mass of the polymer (PA-21) in terms of solid content, and the mixture was diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=50 / 50 (mass ratio) and a solid content concentration 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 (R-43).

[0167] (2) Manufacturing of optical vertical type liquid crystal display elements The liquid crystal alignment agent (R-43) prepared in (1) above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. The coating was then heated at 230°C for 1 hour in an oven with the interior replaced with nitrogen, forming a coating film with a thickness of 0.1 μm. Next, the surface of this coating was irradiated with polarized ultraviolet light at 1,000 J / m², including a 313 nm emission line, using an Hg-Xe lamp and a Glan-Taylor prism. 2 The substrate was irradiated with light from a direction tilted by 40° from the normal to the substrate to impart liquid crystal alignment ability. The same procedure was repeated to prepare a pair (two substrates) having a liquid crystal alignment film. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film. The pair of substrates were then placed with the liquid crystal alignment film surfaces facing each other and pressed together so that the UV light axes of the substrates were antiparallel to each other. The adhesive was then thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrate was heated to 130°C and then slowly cooled to room temperature.

[0168] (3) Evaluation of sublimation contaminants The same procedure as in Example 24 was carried out except that the liquid crystal alignment agent (R-43) prepared in (1) above was used, and the sublimation foreign matter was evaluated based on the number of foreign matters. The evaluation was carried out according to the same criteria as in Example 24. As a result, no foreign matter was found in this example, and the evaluation was "excellent."

[0169] (4) Evaluation of voltage holding ratio For the optical vertical type liquid crystal display element manufactured in (2) above, a voltage of 5 V was applied at 23°C for 60 microseconds over a span of 167 milliseconds, and then the voltage holding ratio (VHR) was measured 1,000 milliseconds after the voltage was removed. A voltage holding ratio of 99.8% or more was rated "excellent," 98.0% or more but less than 99.8% was rated "good," and less than 98.0% was rated "poor." As a result, in this example, the result was "excellent."

[0170] (5) Bright spot evaluation after vibration test A 3 kg weight was attached to the optical vertical liquid crystal display element manufactured in (2) above, and vibration of 200 Hz was applied for 1 hour using a vibration tester. The optical vertical liquid crystal display element was observed under an optical microscope, and the number of bright spots within a 500 μm × 500 μm area was counted. A number of bright spots less than 5 within a 500 μm × 500 μm area was rated "excellent," 5 to 10 was rated "good," and 10 or more was rated "poor." As a result, no bright spots were observed in this example, and it was rated "excellent."

[0171] [Table 4]

[0172] [Example 44: PSA type liquid crystal display element] (1) Preparation of liquid crystal alignment agent To a solution containing the polymer (PI-23) obtained in Synthesis Example 58, the polymer (MI-2) obtained in Synthesis Example 60 was added so that the ratio of polymer (MI-2) to polymer (PI-23) was 90 parts by mass and 10 parts by mass, calculated as solid content, and the mixture was diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=50 / 50 (mass ratio) and a solid content 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 (R-44).

[0173] (2) Preparation of liquid crystal composition 5% by mass of a liquid crystal compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added to 10 g of nematic liquid crystal (MLC-6608, manufactured by Merck) and mixed to obtain liquid crystal composition LC1. [ka]

[0174] (3) Manufacturing of PSA type liquid crystal display elements The liquid crystal alignment agent (R-44) prepared above was applied to the transparent electrode surface of a glass substrate with an ITO transparent electrode using a spinner. After pre-baking for 1 minute on a hot plate at 80°C, the substrate was heated in a nitrogen-purged oven at 230°C for 1 hour to remove the solvent, forming a 0.1 μm-thick coating film. This coating film was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.1 mm. The substrate was then ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. This process was repeated to obtain a pair (two substrates) of substrates with liquid crystal alignment films. Note that this rubbing treatment was a weak one, performed to suppress liquid crystal collapse and facilitate alignment division. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film, and then the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, overlapped, and pressed together, followed by heating at 150°C for 1 hour to thermally cure the adhesive. Next, liquid crystal composition LC1 was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To prevent flow alignment during liquid crystal injection, the resulting mixture was heated at 150°C for 10 minutes and then slowly cooled to room temperature. Next, an AC voltage of 10 V at a frequency of 60 Hz was applied between the electrodes of the obtained liquid crystal cell, and while the liquid crystal was in a driving state, ultraviolet rays of 50,000 J / m were irradiated using an ultraviolet irradiation device that used a metal halide lamp as a light source. 2The irradiation amount was measured using an actinometer measuring at a wavelength of 365 nm as a reference. A PSA liquid crystal cell was thus produced.

[0175] (4) Evaluation of sublimation contaminants The same procedure as in Example 24 was carried out except that the liquid crystal alignment agent (R-44) prepared in (1) above was used, and the sublimation foreign matter was evaluated based on the number of foreign matters. The evaluation was carried out according to the same criteria as in Example 24. As a result, no foreign matter was found in this example, and the evaluation was "excellent."

[0176] (5) Evaluation of voltage holding ratio For the PSA-type liquid crystal display element manufactured in (3) above, a voltage of 5 V was applied at 23°C for 60 microseconds over a span of 167 milliseconds, and then the voltage holding ratio (VHR) was measured 1,000 milliseconds after the application was removed. A voltage holding ratio of 99.8% or more was rated "excellent," 98.0% or more but less than 99.8% was rated "good," and less than 98.0% was rated "poor." As a result, in this example, the result was "excellent."

[0177] (6) Bright spot evaluation after vibration test A 3 kg weight was attached to the PSA type liquid crystal display element manufactured in (3) above, and vibration of 200 Hz was applied for 1 hour using a vibration tester. The PSA type liquid crystal display element was observed under an optical microscope, and the number of bright spots within a 500 μm × 500 μm area was counted. A value of less than 5 bright spots within a 500 μm × 500 μm area was rated "excellent," a value of 5 to 10 bright spots was rated "good," and a value of 10 or more bright spots was rated "poor." As a result, no bright spots were observed in this example, and the evaluation was "excellent."

[0178] [Table 5]

[0179] As shown in Tables 2, 3, 4 and 5, the liquid crystal alignment agents of Examples 1 to 44 were evaluated as "excellent" or "good" in the rubbing resistance evaluation or the sublimation foreign matter evaluation, and were evaluated as "excellent" or "good" in the voltage holding ratio and the bright spot evaluation after the vibration test, showing a good balance of various properties. In contrast, the liquid crystal alignment agents of Comparative Examples 1 to 20 were evaluated as "poor" in at least one of the rubbing resistance, the sublimation foreign matter evaluation, the voltage holding ratio and the bright spot evaluation after the vibration test, showing a poor balance of various properties compared to the Examples.

[0180] Considering the results of the Examples and Comparative Examples, Examples 1 to 23 were rated "good" or "excellent" in terms of rubbing resistance. These examples contain amino groups capable of intermolecular cross-linking in the polymer side chains, and it is presumed that these amino groups react with carboxyl groups or maleimide groups in the polymer, improving the toughness of the liquid crystal alignment film, thereby suppressing film scraping due to rubbing treatment and reducing the number of foreign particles.

[0181] In contrast, the rubbing resistance of Comparative Examples 1 to 6, in which the nitrogen-containing group in the polymer was a cyclic amino group, and Comparative Example 9, in which an amino group was present in the polymer main chain, was "poor." This is presumably because, from the standpoint of steric hindrance and molecular mobility, the reactivity of the amino groups in Comparative Examples 1 to 6 and 9 was poor, and the crosslinking reaction was relatively difficult to proceed, so that the rubbing resistance did not improve under more severe rubbing conditions. Furthermore, the rubbing resistance of Comparative Example 10, in which the polymer did not contain a reactive functional group, was "poor."

[0182] Regarding the evaluation of sublimation foreign matter, Examples 24 to 42 were rated "good" or "excellent." This is presumably because the polymer side chains contain amino groups capable of intermolecular crosslinking, which react with carboxyl groups or maleimide groups in the polymer, reducing the sublimation of the photodecomposition product. Furthermore, Examples 24 to 42 contain alkyl chains in the polymer main chain (i.e., fewer rigid components), which reduces interactions such as π stacking, making it difficult for the sublimated photodecomposition product to return to a solid state. As a result, the photodecomposition product had low sublimation property and the sublimated photodecomposition product had low adhesion to the furnace, which is presumably why there was little sublimation foreign matter.

[0183] On the other hand, the evaluation of sublimation foreign matter in Comparative Examples 11 to 20 was "poor." The nitrogen-containing group in the polymer used in Comparative Examples 11 to 16 was a cyclic amino group, and Comparative Example 19 had an amino group in the polymer main chain, so it is presumed that the reactivity of the amino group was poor and the sublimation of the photodecomposition product was not suppressed. Furthermore, Comparative Examples 17 and 18 contain a highly rigid structure in the polymer main chain, so it is presumed that the adhesion of the photodecomposition product to the furnace was not suppressed. Comparative Example 20, which does not contain an amino group in the polymer, did not suppress the sublimation of the photodecomposition product and was therefore evaluated as "poor."

[0184] The voltage holding ratio was rated as "excellent" or "good" in Examples 1 to 44. This is presumably because the intermolecular interaction of the amino group in formula (1) suppresses molecular mobility, thereby suppressing dielectric polarization and improving the voltage holding ratio.

[0185] The bright spot evaluation after the vibration test was "excellent" or "good" for Examples 1 to 44. The polymers used in Examples 1 to 44 contain amino groups capable of intermolecular cross-linking in the polymer side chains, which are thought to have reacted with carboxyl groups and maleimide groups in the polymer, improving the toughness of the liquid crystal alignment film. Furthermore, the inclusion of alkyl chains in the polymer main chain is thought to have increased the flexibility of the polymer. It is presumed that such high toughness and flexibility made the liquid crystal alignment film less susceptible to damage due to vibration, resulting in a reduced number of bright spots after the vibration test.

[0186] On the other hand, Comparative Examples 1 to 20 were evaluated as "poor" for bright spots after the vibration test. It is believed that Comparative Examples 1 to 6, 9, 11 to 16, and 19 had poor reactivity of the amino groups as described above, and thus did not improve the toughness of the polymer. It is also believed that Comparative Examples 7, 8, 17, and 18 contained a highly rigid structure in the polymer main chain, and therefore did not improve the flexibility of the polymer. The above discussion is merely speculation and does not limit the contents of the present disclosure in any way.

Claims

1. A liquid crystal aligning agent comprising a polymer [P] selected from the group consisting of polyamic acids, polyamic acid esters and polyimides, and having a partial structure represented by the following formula (1) in its main chain: 【Chemistry 1】 (In formula (1), R １ is a hydrogen atom. ２ is a hydrogen atom or a monovalent organic group. １ is a single bond. １ is a monovalent group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base. "*" represents a bond that bonds to an atom constituting the polymer main chain.

2. The liquid crystal aligning agent according to claim 1, wherein the polymer [P] has at least one selected from the group consisting of a partial structure represented by the following formula (2) and a partial structure represented by the following formula (3): 【Chemistry 2】 (In formula (2) and formula (3), Y １ is a tetravalent organic group. ２ is a divalent group having a partial structure represented by the above formula (1). ３ and R ４ are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms.

3. The Y ２ The liquid crystal aligning agent according to claim 2, wherein: is a divalent group represented by the following formula (4): 【Transformation 3】 (In formula (4), A １ and A ２ are each independently a divalent aromatic ring group. １ , B ２ and B ３ are each independently a single bond, —CO—NR ５ -, -NR ５ -CO-, -CO-O-, -O-CO-, -NR ５ -CO-NR ６ -, -NR ５ -CO-O-, -O-CO-NR ５ -, -O-, -S-, a linear alkanediyl group having 1 to 12 carbon atoms, or any methylene group in a linear alkanediyl group having 2 to 12 carbon atoms is -CO-NR ５ -, -NR ５ —CO—, —NR ５ -, -CO-O-, -O-CO-, -NR ５ -CO-NR ６ -, -NR ５ -CO-O-, -O-CO-NR ５ is a divalent group substituted with -, -O- or -S-. ５ and R ６ are each independently a hydrogen atom or a monovalent organic group. m is 0 or 1. １ , X １ and R ２ has the same meaning as in formula (1). When m is 1, multiple R ２ are the same or different. "*" represents a bond.)

4. The above D １ The liquid crystal aligning agent according to claim 1, wherein is a group represented by the following formula (5): 【Chemistry 4】 (In formula (5), R ７ is a monovalent organic group having 1 to 20 carbon atoms. "*" represents a bond bonded to a nitrogen atom.

5. The liquid crystal aligning agent according to claim 1, further comprising a polymer not having a partial structure represented by the formula (1) in the main chain.

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

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

8. The method for producing a liquid crystal alignment film according to claim 7 , further comprising a step of heating the coating film that has been subjected to the light irradiation treatment at a temperature of 120° C. or more and 280° C. or less.

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

10. A polymer having at least one selected from the group consisting of a partial structure represented by the following formula (2) and a partial structure represented by the following formula (3): 【Transformation 5】 (In formula (2) and formula (3), Y １ is a tetravalent organic group. ２ R is a divalent organic group having a partial structure represented by the following formula (1): ３ and R ４ are each independently a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. 【Transformation 6】 (In formula (1), R １ is a hydrogen atom. ２ is a hydrogen atom or a monovalent organic group. １ is a single bond. １ is a monovalent group that is substituted for a hydrogen atom by at least one of heat, light, acid, and base. "*" represents a bond that bonds to an atom that constitutes the polymer main chain.

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