Polyimide Varnish

Abstract

Provided is a polyimide varnish which can be inhibited from suffering blushing due to moisture absorption, changes little in viscosity, has excellent storage stability, is less apt to cause foreign matter, clogging, etc. when used in obtaining films, the obtained films having little surface roughness and being able to have properties inherent in the polyimide material even after drying and heating, and is suitable for use in forming, for example, a liquid-crystal alignment film. The polyimide varnish is characterized by comprising the following ingredient (A) and ingredient (B). Ingredient (A): a polyimide (A) which is a product of imidization of a polyimide precursor. Ingredient (B): an amine compound (B) having, in the molecule, a secondary or tertiary amino group and a cyclic group that is either a nitrogenous aromatic heterocycle or an aromatic hydrocarbon group, the amino group having been bonded to an acyclic aliphatic hydrocarbon group or a nonaromatic cyclic hydrocarbon group.

Description

[Technical Field]

[0001] The present invention relates to a polyimide varnish that is suitable as a liquid crystal aligning agent and can suppress whitening due to moisture absorption. [Background technology]

[0002] Polyimides are widely used as protective and insulating materials in the electrical and electronic fields due to their high mechanical strength, heat resistance, and solvent resistance. Specifically, thin polyimide films are typically formed on various support substrates. For example, when used as insulating films for semiconductors, polyimide films with a thickness of 1–10 μm are formed on silicon substrates with wiring patterns. When used as liquid crystal alignment films, polyimide films with a thickness of 0.05–0.2 μm are formed on transparent substrates with transparent electrodes. Polyimide films are typically formed by applying a polyimide varnish, in which polyimide is dissolved in an appropriate organic solvent, to the substrate using methods such as spin coating, offset printing, gravure printing, flexographic printing, or inkjet printing, followed by a heat treatment.

[0003] While polyimides have excellent properties as various protective and insulating materials, they have the drawback of poor solubility in organic solvents. Therefore, when dissolving polyimides in organic solvents, highly soluble organic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and hexamethylphosphoramide are commonly used. However, although these solvents have high solubility, they have the drawback of being highly hygroscopic.

[0004] Therefore, when a film is obtained using a polyimide varnish containing these organic solvents, the resulting film tends to be easily affected by the environment in which it is applied, etc. In particular, when the application is performed in a humid environment, there is a problem that the solubility of the composition decreases due to moisture absorption before heat treatment, the polyimide precipitates, and the film turns white (hygroscopic whitening). Furthermore, even if a film that has undergone hygroscopic whitening is dried or heated, there are problems such as the inability to obtain the original polyimide properties and the resulting film becoming rough on the surface. Furthermore, when a film is obtained by flexographic printing using a polyimide varnish, the polyimide component may precipitate on the flexographic printing plate, resulting in printing foreign matter, or the polyimide component may precipitate in the ejection head of an inkjet device, causing clogging of the head, leading to defects in the process.

[0005] As a method for suppressing the above-mentioned whitening due to moisture absorption and precipitation of polyimide components in polyimide varnish, it has been proposed to use a high-boiling solvent such as N-vinylpyrrolidone or N-cyclohexylpyrrolidone as 50% or more of the solvent (Patent Document 1). Also, it has been proposed to add a polyol compound having 3 to 15 carbon atoms and having a tertiary nitrogen atom and a quaternary carbon atom to the polyimide varnish (Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-117587 [Patent Document 2] International Publication (WO) No. 2011 / 129414 Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above circumstances, an object of the present invention is to provide a polyimide varnish suitable as a liquid crystal alignment agent, which can suppress the phenomenon of whitening due to moisture absorption, has little change in viscosity and excellent storage stability, is less likely to produce foreign matter or clogs when obtaining a film, and the obtained film has little surface roughness, and is able to retain the original properties of the polyimide material even after drying or heating. [Means for solving the problem]

[0008]

[0003] As a result of intensive research to achieve the above object, the present inventors have noticed that the above-mentioned whitening can be eliminated by increasing the water solubility of polyimide in varnish, and have found that the whitening phenomenon due to moisture absorption can be suppressed by adding an amine compound having a secondary amino group or a tertiary amino group and a specific cyclic group to a polyimide varnish in order to increase the water solubility of the polyimide. On the other hand, it has also become clear that when the amine compound is a primary amine compound, the viscosity of the varnish is unstable and the storage stability is significantly deteriorated.

[0009] The present invention is based on the above findings and has the following gist. A polyimide varnish characterized by containing the following component (A) and component (B): Component (A): Polyimide (A) which is an imidized product of a polyimide precursor. Component (B): An amine compound (B) having, in the molecule, either a secondary amino group or a tertiary amino group and either a nitrogen-containing aromatic heterocyclic group or an aromatic hydrocarbon group as a cyclic group, wherein the amino group is bonded to an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group. [Effects of the Invention]

[0010] According to the present invention, a polyimide varnish is provided which can suppress the phenomenon of whitening due to moisture absorption, has little change in viscosity and excellent storage stability, is less likely to produce foreign matter or clog the ejection head of an inkjet device when obtaining a film, and the obtained film has little surface roughness, and is able to retain the properties of the original polyimide material even after drying or heating. The mechanism by which the above-described effects of the present invention are obtained is not entirely clear, but the following is thought to be one of the reasons. Although polyimides are generally known to have low solubility, in the case of partially imidized polyimides, carboxylic acids derived from the tetracarboxylic dianhydrides remain, and it is possible to improve water solubility by forming a salt between the carboxylic acid and an amine. By forming a salt between the amine and the polyimide in this way, it is possible to suppress precipitation of the polyimide when the polyimide varnish absorbs moisture. On the other hand, polyimides have an abundance of electrophilic carbonyl groups, making them susceptible to nucleophilic attack by nucleophiles such as aliphatic amine compounds. In particular, polyimides derived from aromatic tetracarboxylic dianhydrides tend to have a planar structure and little steric hindrance, making them more susceptible to nucleophilic attack by aliphatic amines. Therefore, from the perspective of ensuring minimal viscosity change and storage stability, it is preferable to use alicyclic and aliphatic tetracarboxylic dianhydrides as raw materials for polyimides. This approach reduces the risk of aliphatic amines acting as nucleophiles and undergoing nucleophilic addition to polyimides, resulting in a polyimide varnish with minimal viscosity change and high storage stability. Furthermore, from the viewpoint of minimizing viscosity change and ensuring storage stability, it is preferable that the basicity of the polyimide varnish is low, and by adopting such an embodiment, it is possible to reduce the decrease in the molecular weight of the polyimide and the decrease in the viscosity of the polyimide varnish. The amine compounds of the present invention, which have either a secondary amino group or a tertiary amino group in the molecule, are unlikely to undergo nucleophilic attack due to their large steric hindrance, but they do form salts between the amine and carboxylic acid, which is thought to prevent precipitation of polyimide varnish due to moisture absorption. The polyimide varnish of the present invention is suitable for use as a protective material, an insulating material, etc., typified by a liquid crystal alignment agent. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Polyimide (A)> The polyimide varnish of the present invention contains the following component (A): Component (A): Polyimide (A) which is an imidized product of a polyimide precursor. The polyimides (A) can be used singly or in combination of two or more. The polyimide precursor is a precursor that generates a polyimide by the imidization reaction of a polyamic acid, a polyamic acid ester, or the like, and is preferably a polyamic acid obtained by the (polycondensation) reaction of a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride or a derivative thereof with a diamine component. Examples of the derivative of the tetracarboxylic acid dianhydride include tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid diester dichloride, and tetracarboxylic acid diester.

[0012] Various tetracarboxylic dianhydrides or derivatives thereof can be used as the tetracarboxylic dianhydride or its derivative. Examples of the tetracarboxylic dianhydride or its derivative include aromatic, acyclic aliphatic, or alicyclic tetracarboxylic dianhydrides, or derivatives thereof. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an aromatic ring. The acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it does not need to be composed solely of a chain hydrocarbon structure, and it may partially contain an alicyclic structure or an aromatic ring structure. Furthermore, the alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups are bonded to an aromatic ring. Furthermore, it does not need to be composed solely of an alicyclic structure, and it may partially contain a chain hydrocarbon structure or an aromatic ring structure.

[0013] In the present invention, from the viewpoint of ensuring minimal viscosity change and storage stability, it is preferable to use an acyclic aliphatic or alicyclic tetracarboxylic acid dianhydride or a derivative thereof as the tetracarboxylic acid derivative component. Among these, it is more preferable to use a tetracarboxylic acid dianhydride or a derivative thereof having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure. The amount used is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, based on 1 mol of the total tetracarboxylic acid derivative components used. When the tetracarboxylic acid derivative contains a tetracarboxylic acid dianhydride or a derivative thereof other than the above tetracarboxylic acid dianhydrides and their derivatives, the upper limit is preferably 95 mol% or less, more preferably 90 mol% or less.

[0014] As the tetracarboxylic dianhydride or a derivative thereof, it is particularly preferable to use a tetracarboxylic dianhydride or a derivative thereof represented by the following formula (3).

[0015] [ka] In the above formula (3), X represents a structure selected from the group consisting of the following (x-1) to (x-13).

[0016] [ka]

[0017] In the above formulas (x-1) to (x-13), R 1 ~R 4 R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a fluorine atom, a monovalent organic group containing a fluorine atom and having 1 to 6 carbon atoms, or a phenyl group. 5 and R 6each independently represents a hydrogen atom or a methyl group. j and k each independently represent an integer of 0 or 1, and A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, phenylene, a sulfonyl group, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. Two A2s may be the same or different. Among these, it is preferable that X is any one of the above formulae (x-1) to (x-7) and (x-11) to (x-13).

[0018] More preferred examples of the above formula (x-1) include the following formulae (x1-1) to (x1-6): In the formula, * represents a bond.

[0019] [ka]

[0020] The proportion of the tetracarboxylic dianhydride represented by the formula (3) or its derivative is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to 1 mol of the tetracarboxylic acid component used. When the tetracarboxylic acid derivative contains a tetracarboxylic dianhydride other than the tetracarboxylic dianhydride represented by the formula (3) or a derivative thereof, or a derivative thereof, the upper limit is preferably 95 mol% or less, more preferably 90 mol% or less. The above tetracarboxylic dianhydrides or derivatives thereof can be used alone or in combination of two or more.

[0021] On the other hand, the diamine component for obtaining the polyamic acid is not particularly limited, and various diamines can be used. In particular, in the present invention, when polyimide is used as a liquid crystal alignment agent for vertical alignment mode, a diamine having at least one side chain structure selected from the group consisting of the following formulae (S1), (S2), and (S3) (hereinafter also referred to as a specific diamine) is preferably used as a diamine exhibiting high vertical alignment ability. [ka] [ka] [ka]

[0022] In the above formula (S1), X 1 and X 2 are each independently a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO-, or -((CH2) a1 -A1) m1 In this, a1 is an integer of 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is 1 to 2. From the viewpoint of availability of raw materials and ease of synthesis, X1 and X2 are each independently a single bond, -(CH2) a - (where a is an integer of 1 to 15), -O-, -CH2O- or -COO- is preferred, and a single bond, -(CH2) a - (where a is an integer of 1 to 10), -O-, -CH2O- or -COO- is more preferred.

[0023] G1 and G2 each independently represent a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. m and n each independently represent an integer of 0 to 3, and the sum of m and n is 1 to 6, preferably 1 to 4. Among these, examples of divalent aromatic groups having 6 to 12 carbon atoms include phenylene, biphenyl structure, naphthalene, etc. Furthermore, examples of divalent alicyclic groups having 3 to 8 carbon atoms include cyclopropylene, cyclohexylene, etc.

[0024] R1 represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. 1 Any hydrogen atom forming the formula may be substituted with a fluorine atom. X 1 , X 2 , G 1 , G 2 , a1, and A1, if there are two or more, then there are two or more X 1 , X 2 , G 1 , G 2 , a1, and A1 may each independently be the same or different.

[0025] Preferred specific examples of the above formula (S1) include the following formulae (S1-x1) to (S1-x7). [ka]

[0026] In formulas (S1-x1)~(S1-x7), R 1 is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms, and X p is -(CH2) a A1 represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)), -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -CHOCO-, -COO-, or -OCO-; A1 represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)) a2 A2 is an oxygen atom or *-COO- (where the bond marked with "*" is (CH2) a2 a1 and a3 each independently represent an integer of 0 or 1, a2 represents an integer of 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group.

[0027] In the above formula (S2), X 3represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -COO- or -OCO-. Among these, -CONH-, -NHCO-, -O-, -CHO-, -COO- or -OCO- is preferred from the viewpoint of liquid crystal alignment. R 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and R 2 Any hydrogen atom forming the group may be substituted with a fluorine atom. Among them, from the viewpoint of liquid crystal alignment, an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is preferred.

[0028] As a preferred embodiment of the formula [S2], X 3 is any one of -O-, -CHO-, -COO-, or -OCO-, and R 2 is preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and R 2 is more preferably an alkyl group having 3 to 20 carbon atoms, and R 2 Any hydrogen atom forming the formula may be substituted with a fluorine atom.

[0029] In the above formula (S3), X 4 represents -CONH-, -NHCO-, -O-, -CH2O-, -OCH2-, -COO- or -OCO-. R 3 represents a structure having a steroid skeleton, and a specific example is a structure having a skeleton represented by the following formula (st): [ka]

[0030] An example of the above formula (S3) is the following formula (S3-x). [ka]

[0031] In formula (S3-x), X represents the above formula (X1), (X2), or (X3). Col represents one selected from the group consisting of the above formulas (Col1) to (Col4), and G represents the above formula (G1) or (G2). * represents a site for bonding to another group. More preferred structures of formula (S3) include structures represented by the following formulae (S3-1) to (S3-6).

[0032] [ka] (* indicates the bond position)

[0033] Specific examples of the specific diamine include diamines of the following formulae (V-1) to (V-13).

[0034] [ka] [ka]

[0035] In the formula, X v1 ~X v4 , X p1 ~X p8 are each independently -(CH2) a - (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CHO-, -CHOCO-, -COO-, or -OCO-; X v5 represents -O-, -CHO-, -CHOCO-, -COO-, or -OCO-; X V6 ~X V7 , X s1 ~X s4 Each independently represents -O-, -CH2O-, -OCH2-, -COO- or -OCO-. X a ~X f are each independently a single bond, -O-, -NH-, or -O-(CH2) m -O-, -C(CH3)2-, -CO-, -COO-, -CONH-, -(CH2)m -, -SO2-, -OC(CH3)2-, -CO-(CH2) m -, -NH-(CH2) m -, -NH-(CH2) m -NH-, -SO2-(CH2) m -, -SO2-(CH2) m -SO2-, -CONH-(CH2) m -, -CONH-(CH2) m -NHCO- or -COO-(CH2) m -OCO- indicates R v1 ~R v4 , R 1a ~R 1h each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. m represents an integer of 1 to 8.

[0036] From the viewpoint of imparting liquid crystal alignment properties, the content of the specific diamine is preferably 5 to 95 mol %, more preferably 5 to 90 mol %, and particularly preferably 5 to 80 mol %, based on the total diamine components.

[0037] The specific diamines may be used alone or in combination of two or more.

[0038] <Other diamines> The diamine for obtaining the polyamic acid may be a diamine other than the above-mentioned specific diamines (also referred to as other diamines). The other diamines may be used alone or in combination of two or more. Specific examples of other diamines include p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,5-diaminophenol, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4 '-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-biphenyl, 3,3'-trifluoromethyl-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane,

[0039] 2,2'-Diaminodiphenylmethane, 2,3'-Diaminodiphenylmethane, 4,4'-Diaminodiphenyl ether, 3,3'-Diaminodiphenyl ether, 3,4'-Diaminodiphenyl ether, 2,2'-Diaminodiphenyl ether, 2,3'-Diaminodiphenyl ether, 4,4'-Sulfonyldianiline, 3,3'-Sulfonyldianiline, Bis(4-aminophenyl)silane, Bis(3-aminophenyl)silane, Dimethyl-bis(4-aminophenyl)silane, Dimethyl-bis(3-aminophenyl)silane, 4,4'-Thiodianiline, 3,3'-Thiodianiline, 4,4'-Diaminodiphenylamine, 3,3'-Diaminodiphenylamine, 3,4'-Diaminodiphenylamine, 2,2'-Diaminodiphenylamine, 2,3'-Diaminodiphenylamine, N-Methyl(4,4'-diaminodiphenyl) Amine, N-methyl(3,3'-diaminodiphenyl)amine, N-methyl(3,4'-diaminodiphenyl)amine, N-methyl(2,2'-diaminodiphenyl)amine, N-methyl(2,3'-diaminodiphenyl)amine, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 1,4-diaminonaphthalene, 2,2'-diaminobenzophenone, 2,3 '-Diaminobenzophenone, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,8-diaminonaphthalene, 1,2-bis(4-aminophenyl)ethane, 1,2-bis(3-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane,

[0040] 1,3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-[1,4-phenylenebis(methylene)]dianiline, 4,4'-[1,3-phenylenebis(methylene)]dianiline, 3,4'-[1,4-phenyl phenylenebis(methylene)]dianiline, 3,4'-[1,3-phenylenebis(methylene)]dianiline, 3,3'-[1,4-phenylenebis(methylene)]dianiline, 3,3'-[1,3-phenylenebis(methylene)]dianiline, 1,4-phenylenebis[(4-aminophenyl)methanone], 1,4-phenylenebis[(3-aminophenyl)methanone], 1,3-phenylenebis[(4-aminophenyl)methanone], 1,3-phenylenebis[(3-aminophenyl)methanone], 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate),

[0041] 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate, N,N'-(1,4-phenylene)bis(4-aminobenzamide), N,N'-(1,3-phenylene)bis(4-aminobenzamide), N,N'-(1,4-phenylene) Bis(3-aminobenzamide), N,N'-(1,3-phenylene)bis(3-aminobenzamide), N,N'-bis(4-aminophenyl)terephthalamide, N,N'-bis(3-aminophenyl)terephthalamide, N,N'-bis(4-aminophenyl)isophthalamide, N,N'-bis(3-aminophenyl)isophthalamide, 9,10-bis(4-aminophenyl)anthracene, 4,4'-bis( 4-aminophenoxy)diphenyl sulfone, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis(3-amino-4-methylphenyl)hexafluoropropane, 2 ,2'-bis(4-aminophenyl)propane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(3-amino-4-methylphenyl)propane, 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, 1,3-bis(4-aminophenoxy)propane, 1,3-bis(3-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,4-bis(3-aminophenoxy)butane,

[0042] 1,5-bis(4-aminophenoxy)pentane, 1,5-bis(3-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,6-bis(3-aminophenoxy)hexane, 1,7-bis(4-aminophenoxy)heptane, 1,7-(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy) 1,10-bis(4-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, diamines represented by the following formulas (nh-1) to (nh-8), diamines represented by the following formulas (z-1) to (z-14), diamines represented by the following formulas (R1) to (R5), diamines having a radical initiation function such as diamines represented by the following formulae (5-1) to (5-11), diamines having the group "-N(D)-" (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom, preferably a tert-butoxycarbonyl group), such as diamines represented by the following formulae (Dp-1) to (Dp-6), diamines having a photopolymerizable group at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline. Examples of suitable diamines include aromatic diamines such as amine, alicyclic diamines such as bis(4-aminocyclohexyl)methane and bis(4-amino-3-methylcyclohexyl)methane, and aliphatic diamines such as 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. [ka] [ka] [ka] [ka] (In formulas (R3) to (R5), n is an integer of 2 to 6.)

[0043] [ka] (Boc represents a tert-butoxycarbonyl group.)

[0044] [ka]

[0045] The polyamic acid can be obtained from the tetracarboxylic acid component and the diamine component by a known method. That is, the reaction between the diamine component and the tetracarboxylic acid component is usually carried out in a solvent containing the diamine component and the tetracarboxylic acid component. The solvent used in this reaction is not particularly limited as long as it dissolves the produced polyamic acid. Specific examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, etc. In addition, when the polyamic acid has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [D1] to [D3] can be used.

[0046] [ka] (D 1 and D 2 represents an alkyl group having 1 to 3 carbon atoms. 3 represents an alkyl group having 1 to 4 carbon atoms. These organic solvents may be used alone or in combination. Furthermore, even if a solvent does not dissolve polyamic acid, it may be mixed with the above-mentioned solvent to the extent that the produced polyamic acid does not precipitate.

[0047] The concentration of polyamic acid in the reaction system is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoints that precipitation of polyamic acid is unlikely to occur and a high molecular weight product is easily obtained. The polyamic acid obtained as described above can be precipitated and recovered by pouring the reaction solution into a poor solvent while stirring it thoroughly. Alternatively, the precipitation can be repeated several times, followed by washing with a poor solvent and drying at room temperature or by heating to obtain a purified polyamic acid powder. The poor solvent is not particularly limited, but examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene. The polyamic acid ester can be obtained, for example, by subjecting the above-mentioned polyamic acid to an esterification reaction with an esterifying agent.

[0048] The polyimide (A) contained in the polyimide varnish of the present invention is obtained by imidizing a polyimide precursor such as the above-mentioned polyamic acid or polyamic acid ester. In the polyimide (A), the repeating units of the polyimide precursor are ring-closed, but the ratio of the ring-closed repeating units to all repeating units of the polyimide precursor (also referred to as the ring-closure rate or imidization rate) does not necessarily have to be 100%, but is preferably 20 to 90%, more preferably 30 to 80%, and can be adjusted as desired within this range depending on the application and purpose of the polyimide varnish. When the polyimide varnish of the present invention is used as a liquid crystal aligning agent for forming a liquid crystal alignment film, the imidization rate is preferably from 20 to 95%, more preferably from 30 to 95%.

[0049] The imidization of the polyimide precursor can be carried out, for example, by stirring the polyamic acid in an organic solvent in the presence of a basic catalyst and an acid anhydride. The organic solvent used in the polymerization reaction described above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among these, pyridine is preferred because it has a suitable basicity for promoting the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among these, acetic anhydride is preferred because it facilitates purification after the reaction.

[0050] The temperature when carrying out the above imidization reaction is -20 to 140°C, preferably 0 to 100°C, and the reaction time is 0.5 to 100 hours, preferably 1 to 80 hours. The amount of the basic catalyst is 0.5 to 30 times by mole, preferably 2 to 20 times by mole, the amount of the amic acid, and the amount of the acid anhydride is 1 to 50 times by mole, preferably 3 to 30 times by mole, the amount of the amic acid. The imidization rate of the obtained polymer can be controlled by adjusting the amount of the catalyst, temperature, and reaction time. Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid, it is preferable to recover the obtained polyimide by the means described below, redissolve it in an organic solvent, and use it as a component of the liquid crystal aligning agent of the present invention. The polyimide solution obtained as described above can be poured into a poor solvent with thorough stirring to precipitate the polymer. The precipitate is filtered, washed several times with the poor solvent, and then dried at room temperature or by heating to obtain a purified polyimide powder.

[0051] Considering the strength of the film obtained from the polyimide varnish obtained therefrom, workability during film formation, and coating properties, the molecular weight of the polyimide obtained as described above is preferably 2,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of weight average molecular weight (Mw) measured by Gel Permeation Chromatography (GPC), and more preferably 10,000 to 150,000. Also, the number average molecular weight (Mn) is preferably 3,000 to 100,000, more preferably 10,000 to 50,000.

[0052] <Amine compound (B)> The polyimide varnish of the present invention contains the following component (B): Component (B): An amine compound (B) having, in the molecule, either a secondary amino group or a tertiary amino group and either a nitrogen-containing aromatic heterocyclic group or an aromatic hydrocarbon group as a cyclic group, wherein the amino group is bonded to an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group. The amine compound (B) can be used alone or in combination of two or more. The amine compound (B) is preferably a compound represented by the following formula (1). [ka]

[0053] In the above formula (1), R1 and R2 each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and at least one of R1 and R2 represents an alkyl group having 1 to 5 carbon atoms. The alkyl group having 1 to 5 carbon atoms may be linear or branched, and preferred examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a pentyl group. Ar represents a monovalent group having a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group. A hydrogen atom on the nitrogen-containing aromatic heterocycle or a hydrogen atom on the aromatic hydrocarbon group of Ar may be substituted with an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), a halogen-containing alkyl group, a halogen-containing alkoxy group, a carboxy group, a hydroxy group, or a nitrile group. Preferred examples of the nitrogen-containing aromatic heterocycle include a cyclic structure containing at least one partial structure selected from the group consisting of the following formulas [1a], [1b], and [1c], and more preferably a cyclic structure containing 1 to 4 of the above partial structures.

[0054] [ka] (wherein Y1 is a linear or branched alkyl group having 1 to 5 carbon atoms)

[0055] More preferred examples of the nitrogen-containing aromatic heterocycle include a pyrrole ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, a pyrazoline ring, an isoquinoline ring, a carbazole ring, a purine ring, a thiadiazole ring, a pyridazine ring, a triazine ring, a triazole ring, a pyrazine ring, a benzimidazole ring, a phenanthroline ring, an indole ring, a quinoxaline ring, a benzothiazole ring, a phenothiazine ring, an oxadiazole ring, and an acridine ring. Preferred examples of the aromatic hydrocarbon group include a benzene ring, a naphthalene ring, an azulene ring, an indene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, and a phenalene ring. X represents a divalent organic group containing an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group. X is preferably a divalent acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group. Preferred examples of the acyclic aliphatic hydrocarbon group include a linear or branched alkylene group having 1 to 10 carbon atoms, and an unsaturated alkylene group having 1 to 10 carbon atoms. Preferred examples of the non-aromatic cyclic hydrocarbon group include alicyclic hydrocarbon groups having 3 to 20 carbon atoms, such as a cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclononane ring, cyclodecane ring, cycloundecane ring, cyclododecane ring, cyclotridecane ring, cyclotetradecane ring, cyclopentadecane ring, cyclohexadecane ring, cycloheptadecane ring, cyclooctadecane ring, cyclononadecane ring, cycloicosane ring, tricycloeicosane ring, bicycloheptane ring, decahydronaphthalene ring, norbornene ring, and adamantane ring.

[0056] Among these, X is preferably a group represented by *1-X1-X2-*2 for reasons of ease of synthesis and availability of raw materials. Here, X1 represents a divalent group containing an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group having 1 to 10 carbon atoms. X1 is preferably a divalent acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group having 1 to 10 carbon atoms. Preferred examples of the acyclic aliphatic hydrocarbon group or non-aromatic cyclic hydrocarbon group of X1 are the same as the examples of X described above. X2 is a single bond, -O-, -NH-, -S-, -SO2- or a divalent organic group having 1 to 19 carbon atoms. The total number of carbon atoms owned by X1 and X2 is 1 to 20, and preferably 1 to 10. In addition, *1 is a bond bonded to N in formula (1), and *2 is a bond bonded to Ar in formula (1).

[0057] The N to which R1 and R2 are bonded is bonded to the acyclic aliphatic hydrocarbon group or the non-aromatic cyclic hydrocarbon group.

[0058] Preferred examples of the amine compound (B) include compounds represented by the following formulas (b-1) to (b-14). [ka]

[0059] Among these, the amine compound (B) is preferably one or more compounds represented by any one of the above formulae (b-1) to (b-3) from the viewpoints of the ease of production and availability of raw materials.

[0060] <Polyimide varnish> The polyimide varnish of the present invention contains the polyimide (A) as the component (A) and the amine compound (B) as the component (B). The polyimide varnish can be obtained, for example, by dispersing or dissolving these components in an organic solvent. The total content of polyimide (A) in the polyimide varnish is preferably 1 to 20 mass %, more preferably 1 to 15 mass %, and particularly preferably 1 to 10 mass %, from the viewpoint of ease of uniform mixing with compound (B). The content of the amine compound (B), which is the component (B) in the polyimide varnish, is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass, and particularly preferably 0.1 to 10 parts by mass, per 100 parts by mass of the polyimide (A), in order to efficiently obtain the effects of the present invention and to enhance the stability of the polyimide varnish.

[0061] The organic solvent that may be contained in the polyimide varnish of the present invention is one that disperses or dissolves, preferably dissolves, the polyimide (A) as the component (A) and the amine compound (B) as the component (B). Examples of organic solvents include lactone solvents such as γ-valerolactone and γ-butyrolactone, lactam solvents such as γ-butyrolactam, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, tetramethylurea and N,N-diethylformamide, 4-hydroxy-4-methyl-2-pentanone, diisobutyl ketone (2,6-dimethyl-4-heptanone), methyl lactate, ethyl lactate, n-propyl lactate, n-propyl lactate, -butyl, isoamyl lactate, n-butyl acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-i- Propyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisopentyl ether;Examples of suitable solvents include carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethanediol, diisobutylcarbinol (2,6-dimethyl-4-heptanol), cyclohexanone, and cyclopentanone.

[0062] Preferred combinations when two or more organic solvents are used include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol mono-n-butyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol dibutyl ether, ethyl ether, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone Pentanone and propylene glycol diacetate, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl carbinol, N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone, ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N,Examples include N-dimethylpropionamide and propylene glycol diacetate, tetramethylurea and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone and propylene glycol monomethyl ether, and cyclopentanone and propylene glycol monomethyl ether.

[0063] The polyimide varnish of the present invention may contain, in addition to the polyimide (A) as component (A) and the component (B), various other components (also referred to as "other components") depending on its intended use. Examples of such other components include polymers other than the polyimide (A), antioxidants (phenolic, phosphite, thioether, etc.), ultraviolet absorbers, hindered amine light stabilizers, nucleating agents, resin additives (fillers, talc, glass fibers, etc.), flame retardants, processability improvers, lubricants, etc.

[0064] <Liquid crystal alignment agent> In the case of a liquid crystal aligning agent, which is a preferred application of the polyimide varnish of the present invention, it is preferably prepared so as to be suitable for forming a liquid crystal alignment film. The liquid crystal aligning agent of the present invention preferably contains the polyimide varnish of the present invention. The liquid crystal aligning agent of the present invention can be obtained, for example, by dispersing or dissolving the polyimide varnish of the present invention and, if necessary, other components in an organic solvent. The liquid crystal aligning agent of the present invention may also be obtained by mixing two or more liquid crystal aligning agents. For example, it may be obtained by mixing two or more liquid crystal aligning agents containing the polyimide varnish of the present invention, or by mixing a liquid crystal aligning agent containing the polyimide varnish of the present invention with a liquid crystal aligning agent containing other components. Examples of the other components include polymers other than the polyimide (A), crosslinkable compounds, functional silane compounds, surfactants, compounds having a photopolymerizable group, organic solvents, etc.

[0065] The other polymers are not particularly limited, and examples thereof include polyimide precursors such as polyamic acid and polyamic acid esters, polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, and polymers of monomers having polymerizable unsaturated bonds.Preferably, the other polymers are polymers of monomers having polymerizable unsaturated bonds.The other polymers may be used alone or in combination of two or more. When other polymers are used, the proportion of them used is preferably 50% by mass or less, more preferably 0.1 to 40% by mass, and even more preferably 0.1 to 30% by mass, based on the total amount of polymers contained in the polyimide varnish.

[0066] Examples of the monomer having a polymerizable unsaturated bond include (meth)acrylic compounds (including unsaturated carboxylic acids, unsaturated carboxylic acid esters, and unsaturated polycarboxylic acid anhydrides), (meth)acrylic acid amide compounds, aromatic vinyl compounds, conjugated diene compounds, maleimide group-containing compounds, α-methylene-γ-butyrolactone compounds, vinyl compounds other than aromatic vinyl compounds, and compounds containing a maleic anhydride structure. Examples of polymers of compounds containing a maleic anhydride structure include poly(styrene-maleic anhydride) copolymer, poly(isobutylene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, etc. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (manufactured by Cray Valley) and GSM301 (manufactured by Gifu Shellac Co., Ltd.), a specific example of poly(isobutylene-maleic anhydride) copolymers includes ISOBAN-600 (manufactured by Kuraray), and a specific example of poly(vinyl ether-maleic anhydride) copolymers includes GANTREZ AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by ISP Japan Co., Ltd.).

[0067] In the polymer of the (meth)acrylic compound (hereinafter also referred to as polymer (uA)), the proportion of the (meth)acrylic compound used may be 50 mol % or more, or 60 mol % or more, based on the total amount of monomers used in the synthesis.

[0068] The polymer (uA) can be obtained, for example, by polymerizing a monomer having a polymerizable unsaturated bond in the presence of a polymerization initiator. Examples of the polymerization initiator include azo compounds such as 2,2'-azobis(isobutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile). The polymerization initiator is preferably used in an amount of 0.01 to 30 parts by mass per 100 parts by mass of all monomers used in the reaction. The polymerization reaction is preferably carried out in an organic solvent. Examples of organic solvents used in the reaction include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds, with diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether acetate being preferred. The reaction temperature is preferably 30 to 120°C. The amount of organic solvent (a) used is preferably such that the total amount of monomers (b) used in the reaction is 0.1 to 60% by mass relative to the total amount of the reaction solution (a+b).

[0069] As the monomer for obtaining the polymer (uA), a monomer represented by the following formula (S-mA), a monomer having a carboxy group and a polymerizable unsaturated bond, a monomer having an epoxy skeleton and a polymerizable unsaturated bond, and other monomers having a polymerizable unsaturated bond may be used. [ka] (P represents a (meth)acryloyloxy group, a styryl group, a vinyloxy group (CH2=CH-O-), a maleimide group, or an α-methylene-γ-butyrolactone structure. X is a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1)m1 - (where a1 is an integer of 1 to 15, A1 represents an oxygen atom or -COO-, and m1 is an integer of 1 to 2. When m1 is 2, multiple a1's and A1's each independently have the same meaning as defined above), or the group "-L-OCO-CR'=CR"-". However, when P is a (meth)acryloyloxy group, a vinyloxy group (CH2=CH-O-), or a maleimide group, X represents a single bond or a linking group that bonds to P via a carbon atom. J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, provided that at least one hydrogen atom possessed by the alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond possessed by any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. In addition, when J in the above formula (S-mA) is a monovalent organic group having two or more groups of at least one type selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, it is sufficient that at least one of the alicyclic hydrocarbon groups or aromatic hydrocarbon groups has the above-mentioned substituent, and other alicyclic hydrocarbon groups or aromatic hydrocarbon groups that J in the above formula (S-mA) has may be unsubstituted or may have a substituent other than the above-mentioned examples. In the group "-L-OCO-CR'=CR"-", L is a single bond or -(B1-(CH2) b1 ) m’ -(b1 is an integer of 1 to 15. B1 represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO- or -OCO-. m ’ is an integer between 1 and 2. m ’When the number is 2, a plurality of b1's and B1's each independently have the same definition as above, and at least one B1's represents a linking group other than a single bond. R' and R" represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0070] More preferred examples of the group "-XJ" include groups represented by any of the following formulae (S1) to (S2). [ka] (X 1 is a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO-, -((CH2) a1 -A1) m1 - (a1 is an integer of 1 to 15. A1 represents an oxygen atom or -COO-, and m1 is an integer of 1 to 2. When m1 is 2, multiple a1s and A1s each independently have the same definition as above), or a group "-L-OCO-CR'=CR"-". G 1 represents a divalent cyclic group selected from a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms and a divalent alicyclic hydrocarbon group having 4 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. However, m is an integer of 1 to 4. When m is 2 or more, multiple X 1 , G 1 are each independently defined above. R 1 represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms. In the group "-L-OCO-CR'=CR"-", L is a single bond or -(B1-(CH2) b1 ) m’-(b1 is an integer of 1 to 15. B1 represents a single bond, -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO- or -OCO-. m ’ is an integer between 1 and 2. m ’ When the number is 2, a plurality of b1's and B1's each independently have the same definition as above, and at least one of B1's represents a linking group other than a single bond. In the group "-L-OCO-CR'=CR"-", R' and R" each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. [ka] (X 2 represents -CONH-, -NHCO-, -O-, -CHO-, -OCH-, -COO- or -OCO-. 2 represents a structure having a steroid skeleton, wherein at least one hydrogen atom of the structure having a steroid skeleton is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond of any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted with an oxygen atom.

[0071] In the above formula (S1), G 1 Examples of the divalent cyclic group in the formula (I) include a cyclopropylene group, a cyclohexylene group, and a phenylene group. Any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0072] In the above formula (S2), G 2 Examples of the structure having a steroid skeleton in the formula (I) include a structure containing a cholestanyl group, a cholesteryl group, or a lanostaniyl group.

[0073] Specific examples of the monomer having a carboxy group and a polymerizable unsaturated bond include carboxy group-containing (meth)acrylate compounds such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-hydroxyethyl(meth)acrylic acid, 2-carboxyethyl(meth)acrylate, 2-carboxypropyl(meth)acrylate, 5-carboxypentyl(meth)acrylate, 2-acryloyloxyethylsuccinic acid, and 2-methacryloyloxyethylsuccinic acid; vinyl group-containing aromatic carboxylic acids such as 4-vinylbenzoic acid; carboxy group-containing maleimides such as 4-maleimidobenzoic acid; and carboxy group-containing (meth)acrylamide compounds such as N-(carboxyphenyl)methacrylamide and N-(carboxyphenyl)acrylamide.

[0074] Examples of the monomer having an epoxy skeleton and a polymerizable unsaturated bond include allyl glycidyl ether, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, α-ethyl glycidyl (meth)acrylate, α-n-propyl glycidyl (meth)acrylate, α-n-butyl glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3-ethenyl-7-oxabicyclo[4.1.0]heptane, 1,2-epoxy-5-hexene, and 1,7-octadiene monoepoxide.

[0075] Examples of the other monomers having a polymerizable unsaturated bond include the following monomers.

[0076] amino group-containing (meth)acrylate compounds such as aminoethyl (meth)acrylate and aminopropyl (meth)acrylate; (meth)acrylamide compounds containing a hydroxymethyl group or an alkoxymethyl group, such as N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide; compounds having an oxetane skeleton, such as 3-(acryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl)oxetane, 3-(acryloyloxymethyl)-2-methyloxetane, 3-(methacryloyloxymethyl)-2-methyloxetane, 3-(acryloyloxymethyl)-3-ethyloxetane, and 3-(methacryloyloxymethyl)-3-ethyloxetane; compounds having a nitrogen-containing aromatic heterocycle, such as 2-(2-pyridylcarbonyloxy)ethyl (meth)acrylate, 2-(3-pyridylcarbonyloxy)ethyl (meth)acrylate, and 2-(4-pyridylcarbonyloxy)ethyl (meth)acrylate; (meth)acrylic acid ester compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-propyl-2-adamantyl (meth)acrylate, 8-methyl-8-tricyclodecyl (meth)acrylate, and 8-ethyl-8-tricyclodecyl (meth)acrylate; (Meth)acrylic acid amide compounds such as acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide; Vinyl ether compounds such as methyl vinyl ether, benzyl vinyl ether, vinyl naphthalene, and vinyl carbazole; aromatic vinyl compounds such as styrene, methylstyrene, chlorostyrene, and bromostyrene; and maleimide group-containing compounds such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

[0077] As the monomer components for obtaining polymer (uA), the total content of the monomer having a carboxy group and a polymerizable unsaturated bond, the monomer having an epoxy skeleton and a polymerizable unsaturated bond, and the monomer represented by formula (S-mA) is preferably 10 mol% or more, and more preferably 20 mol% or more. When the other monomer having a polymerizable unsaturated bond is used in combination, the total content of the monomer having a carboxy group and a polymerizable unsaturated bond and the monomer represented by formula (S-mA) is preferably 99 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less.

[0078] The molecular weight of the polymer (uA) obtained as described above is preferably a weight average molecular weight (Mw) of 2,000 to 1,000,000, more preferably 10,000 to 150,000, as measured by GPC (Gel Permeation Chromatography), and more preferably a number average molecular weight (Mn) of 3,000 to 100,000, more preferably 10,000 to 50,000.

[0079] The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of such crosslinkable compounds include compounds having a hydroxyalkylamide bond or a alkoxyalkylamide bond, as described in JP 2016-118753 A and WO 2015 / 156314 A, compounds having at least one group selected from the group consisting of an epoxy group, an oxetane group, a hydroxy group, a hydroxyalkyl group, an isocyanate group, a cyclocarbonate, and a lower alkoxyalkyl group, as described in paragraphs

[0109] to

[0113] of WO 2016 / 047771 A, and compounds having a blocked isocyanate group.

[0080] Examples of the compound having an epoxy group include, among others, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as Epicoat 828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as Epicoat 807 (manufactured by Mitsubishi Chemical Corporation), YX-8000 (manufactured by Mitsubishi Chemical Corporation), and the like. Preferred are hydrogenated bisphenol A epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), biphenyl skeleton-containing epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), phenol novolac epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), (o, m, p-) cresol novolac epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), triglycidyl isocyanurates such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as CELLOXIDE 2021P (manufactured by Daicel Chemical Industries, Ltd.), N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and tetrakis(glycidyloxymethyl)methane.

[0081] Blocked isocyanate compounds are commercially available, and examples that can be preferably used include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, and Millionate MS-50 (all manufactured by Tosoh Corporation), and Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals, Inc.).

[0082] Specific examples of preferred crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11). [ka] [ka] The above are examples of the crosslinkable compound, and the present invention is not limited to these. Two or more types of crosslinkable compounds may be used in combination in the liquid crystal aligning agent of the present invention.

[0083] The content of the crosslinkable compound in the liquid crystal aligning agent is preferably 0.1 to 150 parts by mass, more preferably 0.1 to 100 parts by mass, and particularly preferably 1 to 50 parts by mass, relative to 100 parts by mass of all polymer components. The functional silane compound can be used to improve the adhesion between the liquid crystal alignment film and the base substrate. Specific examples include the silane compounds described in paragraph

[0019] of International Publication No. 2014 / 119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, per 100 parts by mass of all polymer components.

[0084] A surfactant can be used to improve the uniformity of the film thickness and surface smoothness of the liquid crystal alignment film. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these surfactants include those described in paragraph

[0117] of WO2016 / 047771. The amount of surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the total polymer contained in the liquid crystal alignment agent. Examples of compounds having a photopolymerizable group include compounds having one or more polymerizable unsaturated groups such as acrylate groups or methacrylate groups in the molecule, such as compounds represented by any of the following formulas (M-1) to (M-7).

[0085] [ka]

[0086] As the organic solvent that may be contained in the liquid crystal alignment agent, those described in the polyimide varnish can be used, and the type and content of the solvent are appropriately selected depending on the application device, application conditions, application environment, etc. of the liquid crystal alignment agent. The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the organic solvent in the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably 1 to 10 mass%.

[0087] A particularly preferred solid content concentration varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, when using a spin coating method, a concentration of 1 to 10 mass% is particularly preferred. When using a printing method, a concentration of 3 to 9 mass% is particularly preferred, thereby resulting in a solution viscosity of 12 to 50 mPa·s. When using an inkjet method, a concentration of 1 to 5 mass% is particularly preferred, thereby resulting in a solution viscosity of 3 to 15 mPa·s.

[0088] The liquid crystal alignment agent can be used as a liquid crystal alignment film by applying it to a substrate, baking it, and then performing an alignment treatment such as rubbing or light irradiation. In addition, in the case of vertical alignment applications, it can be used as a liquid crystal alignment film without any alignment treatment. The substrate used in this case is not particularly limited as long as it is a highly transparent substrate, and in addition to a glass substrate, a plastic substrate such as an acrylic substrate, a polycarbonate substrate, or a PET (polyethylene terephthalate) substrate, or even a film thereof, can be used. From the viewpoint of process simplification, it is preferable to use a substrate on which a metal electrode for driving the liquid crystal, such as an ITO electrode, an IZO (indium zinc oxide) electrode, or an IGZO (indium gallium zinc oxide) electrode, or an organic conductive film, is formed. When a reflective liquid crystal display element is to be produced, a substrate on only one side can be formed of a silicon wafer, a metal such as aluminum, or a dielectric multilayer film.

[0089] The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, it is generally performed by screen printing, offset printing, flexographic printing, inkjet printing, etc. Other application methods include a dipping method, a roll coating method, a slit coating method, a spin coating method, a spraying method, etc., and these may be used depending on the purpose. After the liquid crystal alignment agent is applied to the substrate, the solvent is evaporated at a temperature of 30 to 300°C, preferably 30 to 250°C, depending on the solvent used in the liquid crystal alignment agent, using a heating means such as a hot plate, a heat circulation oven, or an IR (infrared) oven, to form a liquid crystal alignment film.

[0090] The thickness of the liquid crystal alignment film after baking is preferably 5 to 300 nm, more preferably 10 to 200 nm, since if it is too thick it will be disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin it may reduce the reliability of the liquid crystal display element. When the liquid crystal is to be horizontally or obliquely aligned, the liquid crystal alignment film after baking is treated by rubbing or by irradiating with polarized ultraviolet light. The ultraviolet light preferably contains light having a wavelength of 300 to 400 nm. Examples of light sources that can be used for the irradiation light include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. Ultraviolet light in the preferred wavelength range can be obtained by using the light source in combination with, for example, a filter, a diffraction grating, or the like. The irradiation dose of light is preferably 1,000 J / m. 2 More than 100,000J / m 2 less than 1,000 to 50,000 J / m 2 is. The liquid crystal used in the liquid crystal display element is not particularly limited, but for example, nematic liquid crystal, smectic liquid crystal, or cholesteric liquid crystal can be used. In this case, liquid crystal having positive or negative dielectric anisotropy can be selected depending on the type of liquid crystal display element. In addition, a dichroic dye can be dissolved in the liquid crystal to form a guest-host type liquid crystal display element. The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention can be used as a liquid crystal alignment film for a horizontal alignment type or vertical alignment type liquid crystal display element. As a liquid crystal alignment film for horizontal alignment type liquid crystal display elements, it is suitable as a liquid crystal alignment film for horizontal electric field type liquid crystal display elements such as IPS type and FFS type, or horizontal alignment type liquid crystal display elements such as TN mode, and is particularly useful as a liquid crystal alignment film for FFS type liquid crystal display elements. The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention is particularly suitable as a liquid crystal alignment film for a vertical alignment type liquid crystal display element such as a VA mode or PSA mode. The liquid crystal alignment film for a vertical alignment type liquid crystal display element such as a VA mode or PSA mode may be obtained by an alignment treatment including a photo-alignment treatment. The preferred embodiments of the light, light source, and light irradiation amount to be irradiated in the photo-alignment treatment are as described above. Furthermore, the liquid crystal alignment film obtained from the liquid crystal alignment agent containing the polyimide varnish of the present invention can be used as a liquid crystal alignment film for a retardation film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmissive / scattering liquid crystal dimming element, or for other applications such as a protective film for a color filter, a gate insulating film for a flexible display, or a substrate material.

[0091] The liquid crystal display element using the liquid crystal aligning agent of the present invention can be applied to various devices, such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays. [Example]

[0092] The present invention will be described in further detail below with reference to examples, but is not limited to these examples. The abbreviations and measurement methods for the compounds used below are as follows: (Tetracarboxylic acid dianhydride) BODA: Bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride PMDA: Pyromellitic anhydride TCA: 2,3,5-tricarboxycyclopentylacetic dianhydride TDA: 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride 13DM-CBDA: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride [ka]

[0093] (diamine) PDA: p-phenylenediamine DBA: 3,5-diaminobenzoic acid 3AMPDA: 3,5-diamino-N-(pyridin-3-ylmethyl)benzamide [ka]

[0094] Vertically aligning diamine represented by the following formula DA-1 [ka] Diamines represented by the following formulae DA-2 to DA-9 [ka] (Boc represents a tert-butoxycarbonyl group.) (Methacrylic compounds) Methacrylic compounds represented by the following formulae MA-1 to MA-3 [ka] (Radical polymerization initiator) AIBN: Azobisisobutyronitrile

[0095] <Solvent> NMP: N-methyl-2-pyrrolidone, BCS: butyl cellosolve <Amine compound (B)> 3AMP: 3-picolylamine, Me-3AMP: N-methyl-3-picolylamine MBA: N-methylbenzylamine, DMBA: N,N-dimethylbenzylamine [ka]

[0096] <Molecular weight measurement> Apparatus: Senshu Scientific room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) Column: Shodex column (KD-803, KD-805) Column temperature: 50℃ Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weight: approximately 12,000, 4,000, 1,000) manufactured by Polymer Laboratory.

[0097] <Imidization rate measurement> 20 mg of polyimide powder was placed in an NMR sample tube (Kusano Scientific NMR Sampling Tube Standard, φ5), and 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS mixture) was added. The solution was sonicated to completely dissolve it. Proton NMR was measured at 500 MHz using a JEOL Datum NMR spectrometer (JNW-ECA500). The imidization ratio was calculated using the integrated peak value of this proton and the integrated peak value of the proton derived from the NH group of the amic acid, which appeared around 9.5 to 10.0 ppm, according to the following formula: In the following formula, x represents the integrated value of the proton peak derived from the NH group of the amic acid, y represents the integrated value of the peak of the reference proton, and α represents the ratio of the number of the reference protons to one proton of the NH group of the amic acid in the case of polyamic acid (imidization rate 0%). Imidization rate (%) = (1 - α x / y) x 100

[0098] <Viscosity measurement> The viscosity of the liquid crystal alignment agent was measured at 25°C using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL and a cone rotor TE-1 (1°34', R24).

[0099] (Synthesis Example 1) BODA (15.0 g, 60.0 mmol), DBA (18.3 g, 120 mmol), 3AMPDA (21.8 g, 90.0 mmol), and DA-1 (34.3 g, 90.0 mmol) were dissolved in NMP (357 g) and reacted at 60 °C for 3 hours. PMDA (13.1 g, 60.0 mmol), followed by CBDA (34.1 g, 174 mmol) and NMP (137 g) were then added, and the mixture was reacted at 25 °C for 10 hours to obtain a polyamic acid solution. This polyamic acid solution (500 g) was diluted to 6.5% by mass with NMP, and then acetic anhydride (111 g) and pyridine (34.5 g) were added as imidization catalysts and reacted at 60°C for 3 hours. This reaction solution was poured into methanol (7000 mL), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (A). The imidization rate of this polyimide was 80%, and the number average molecular weight was 12,000 and the weight average molecular weight was 24,000.

[0100] (Synthesis Example 2) TCA (43.9 g, 196 mmol), DA-2 (30.3 g, 40.0 mmol), DA-4 (9.49 g, 40.0 mmol), DA-5 (13.9 g, 70.0 mmol), and DA-6 (16.5 g, 50.0 mmol) were mixed in NMP (455 g) and reacted at 60°C for 15 hours to obtain a polyamic acid solution with a resin solids concentration of 20% by mass. This polyamic acid solution (100 g) was diluted to 6.5% by mass with NMP, and then acetic anhydride (17.9 g) and pyridine (5.55 g) were added as imidization catalysts and reacted at 100°C for 3 hours. This reaction solution was poured into methanol (1160 ml), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain polyimide powder (B). The imidization rate of this polyimide was 72%, and the number average molecular weight was 13,300 and the weight average molecular weight was 40,500.

[0101] (Synthesis Example 3) TDA (30.0 g, 100 mmol), PDA (9.73 g, 90 mmol), and DA-3 (3.77 g, 10.0 mmol) were dissolved in NMP (247 g) and reacted at 40°C for 3 hours to obtain a polyamic acid solution. This polyamic acid solution (50 g) was diluted to 5% by mass with NMP, and then acetic anhydride (17.6 g) and pyridine (8.20 g) were added as imidization catalysts and reacted at 40°C for 3 hours. This reaction solution was poured into methanol (600 ml), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain polyimide powder (C). The imidization rate of this polyimide was 85%, and the number average molecular weight was 13,400 and the weight average molecular weight was 27,000.

[0102] (Synthesis Example 4) 13DM-CBDA (17.1 g, 76.4 mmol), PDA (1.73 g, 16.0 mmol), DA-7 (5.86 g, 24.0 mmol), DA-8 (7.69 g, 24.0 mmol), and DA-9 (5.46 g, 16.0 mmol) were dissolved in NMP (277 g) and reacted at 50°C for 15 hours to obtain a polyamic acid solution. This polyamic acid solution (100 g) was diluted to 9% by mass with NMP, and then acetic anhydride (7.60 g) and pyridine (0.98 g) were added as imidization catalysts and reacted at 55°C for 3 hours. This reaction solution was poured into methanol (530 ml), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain polyimide powder (D). The imidization rate of this polyimide was 66%, and the number average molecular weight was 14,300 and the weight average molecular weight was 35,800.

[0103] (Synthesis Example 5) MA-1 (10.2 g, 20.0 mmol), MA-2 (2.61 g, 30.0 mmol), MA-3 (2.35 g, 16.5 mmol), and NMP (60.6 g) were added to a four-neck flask, and each monomer component was completely dissolved. The solution was degassed using a diaphragm pump, and AIBN (0.550 g, 3.33 mmol) was added as a polymerization initiator. The solution was then degassed again. The reaction was then carried out at 60°C for 13 hours, yielding a methacrylic polymer solution (E). The number-average molecular weight of this polymer was 15,800, and the weight-average molecular weight was 68,200.

[0104] Example 1 NMP (44.0 g) was added to the obtained polyimide powder (A) (6.00 g), and the mixture was dissolved by stirring at 70° C. for 20 hours. To this solution, Me-3AMP (2 mass % NMP solution, 6.00 g) was added as the amine compound (B), and then NMP (4.00 g) and BCS (40.0 g) were added, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal alignment agent (A1).

[0105] (Examples 2 and 3 and Comparative Examples 1 and 2) Liquid crystal aligning agents (A2) to (A5) were prepared in the same manner as in Example 1, except that the type of the added amine compound (B) was changed. The obtained liquid crystal aligning agents and the amine compound (B) used therein are shown in Table 1 below. In Comparative Example 2, the amine compound (B) was not added.

[0106] [Table 1]

[0107] <Storage stability test> The liquid crystal aligning agents obtained in Examples 1 to 3 and Comparative Examples 1 or 2 were placed in a vial and sealed, and left standing in a light-shielded environment at 25°C. The change in viscosity of the liquid crystal aligning agent during standing and the molecular weight of the polyimide contained in the liquid crystal aligning agent were tracked. Table 2 below shows the change in viscosity of the liquid crystal alignment agent, and Table 3 shows the change in molecular weight (number average molecular weight) of the polyimide contained in the liquid crystal alignment agent.

[0108] [Table 2]

[0109] [Table 3]

[0110] <Evaluation of whitening properties> 0.1 mL of the liquid crystal alignment agents obtained in Examples 1 to 3 and Comparative Examples 1 or 2 was dropped onto a chrome substrate and left to stand in an environment of a temperature of 23°C and a humidity of 70%. The edge and center of the droplet were observed with an optical microscope, and the time until a precipitate was generated was measured. In this evaluation, the whitening phenomenon is defined as the phenomenon in which the droplets become cloudy due to precipitation or aggregation of dissolved polyimide. A state in which the droplets are not whitened at all is rated as "Good", a state in which only the edges of the droplets are whitened is rated as "Good", and a state in which the entire surface of the droplets is whitened is rated as "Poor". Table 4 shows the evaluation results of the whitening property after 3 days of the storage stability test of the liquid crystal aligning agent.

[0111] [Table 4]

[0112] The results in Tables 2 and 3 show that, compared to the changes in viscosity and molecular weight in Comparative Example 1, the decreases in viscosity and molecular weight were significantly suppressed in Examples 1 to 3, and the storage stability of the polyimide varnish was improved. Furthermore, the results of the whitening test in Table 4 show that Examples 1 to 3 have significantly improved whitening properties compared to Comparative Example 2. Furthermore, the results in Table 4 show that the whitening properties of Examples 1 to 3 are less likely to deteriorate than those of Comparative Example 1. This is thought to be because the aliphatic amine in 3AMP is a primary amine, which makes it more likely to make a nucleophilic attack on the polyimide main chain, whereas the nucleophilicity of secondary and tertiary amines to the polyimide main chain is suppressed due to the influence of steric hindrance.

[0113] (Examples 4 to 8, Comparative Examples 3 to 12, Synthesis Examples 6 to 8) In Example 1, except that the polyimide powder, amine compound and organic solvent were changed as shown in Table 5 below, the same procedure was carried out to prepare liquid crystal alignment agents (B1) to (B2), (C1) to (C3) and (D1) to (D3). In addition, NMP (24.0 g), BCS (40.0 g), and MBA (2 mass% NMP solution) 6.00 g were added to the methacrylic polymer solution (E) (30.0 g) obtained in Synthesis Example 5, and the mixture was stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (E1) (Synthesis Example 6). Furthermore, in Synthesis Example 6, except that the amine compound was changed as shown in Table 5 below, the liquid crystal aligning agents (E2) to (E3) were prepared by carrying out the same procedure (Synthesis Examples 7 and 8). Table 5 shows the combinations of each liquid crystal alignment agent and the additives used therewith.

[0114] [Table 5]

[0115] Next, the liquid crystal aligning agents (B1) to (B3) and (E1) to (E3) obtained so far were blended with the liquid crystal aligning agents (A2), (A4) and (A5). Table 6 shows the combinations of the blended liquid crystal alignment agents and the combinations of the additives contained in the liquid crystal alignment agents. [Table 6] The liquid crystal aligning agent obtained above was subjected to a storage stability test and evaluation of whitening properties in the same manner as above. The results are shown in Tables 7 to 10 below.

[0116] <Storage stability test> [Table 7] [Table 8]

[0117] <Evaluation of whitening properties> The results of the evaluation carried out on the day of preparation of the liquid crystal alignment agent are shown in Table 9, and the results of the evaluation carried out after 3 days of the storage stability test are shown in Tables 9 and 10. [Table 9] [Table 10]

[0118] The results in Tables 7 and 8 show that in Examples 5 to 8, the decrease in viscosity and molecular weight was significantly suppressed, and the storage stability was improved. Furthermore, the results of the whitening test in Tables 9 and 10 show that Examples 5 to 8 have significantly improved whitening properties compared to Comparative Examples 5 to 12. [Industrial Applicability]

[0119] The polyimide varnish of the present invention is widely used in a wide range of fields, including as a liquid crystal aligning agent for forming a liquid crystal alignment film in a liquid crystal display element, an insulating film for semiconductors, and particularly as a film-like protective material or insulating material in the electrical and electronic fields.

[0120] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2020-30729, filed on February 26, 2020, are hereby incorporated by reference as part of the disclosure of the specification of the present invention.

Claims

1. A polyimide varnish characterized by containing the following components (A) and (B): Component (A): Polyimide (A) which is an imidized product of a polyimide precursor. Component (B): An amine compound (B) having, in the molecule, either a secondary amino group or a tertiary amino group and either a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group as a cyclic group, wherein the amino group is bonded to an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group, and the amine compound (B) is one or more compounds represented by any of the following formulas (b-1) and (b-3) to (b-14): 【Chemical 1】

2. 2. The polyimide varnish according to claim 1, wherein the polyimide precursor of the polyimide (A) is obtained using a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (3) or a derivative thereof: 【Chemistry 2】 (X represents a structure selected from the group consisting of the following (x-1) to (x-13)). 【Chemistry 3】 (R １ ~R ４ R each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a fluorine atom, a monovalent organic group containing a fluorine atom and having 1 to 6 carbon atoms, or a phenyl group. ５ and R ６ each independently represents a hydrogen atom or a methyl group; j and k each independently represent an integer of 0 or 1; A １ and A ２ each independently represents a single bond, -O-, -CO-, -COO-, phenylene, a sulfonyl group, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. ２ may be the same or different.)

3. The tetracarboxylic dianhydride or derivative thereof represented by the formula (3) is a tetracarboxylic dianhydride or derivative thereof, wherein X is any one of the formulae (x-1) to (x-7) and (x-11) to (x-13). The polyimide varnish according to claim 2.

4. The polyimide varnish according to any one of claims 1 to 3, wherein the polyimide precursor of the polyimide (A) is obtained using a diamine (a) having at least one side chain structure selected from the group consisting of the following formulae (S1) to (S3): 【Chemistry 4】 (X １ and X ２ are each independently a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -((CH ２ ) ａ１ -A １ ) ｍ１ In this, a1 is an integer of 1 to 15, and A １ represents an oxygen atom or —COO—, m １ is 1 to 2. G １ and G ２ each independently represents a divalent aromatic group having 6 to 12 carbon atoms or a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted. m and n are each independently an integer of 0 to 3, and m+n is 1 to 6. R １ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms; R １ Any hydrogen atom forming X may be substituted with a fluorine atom. １ , X ２ , G １ , G ２ , a1, and A １ If there are two or more, there are two or more X １ , X ２ , G １ , G ２ , a1, and A １ may be independently the same or different.) 【Chemistry 5】 (X ３ represents a single bond, -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -CH ２ represents —O—, —COO—, or —OCO—. ２ represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and R ２ Any hydrogen atom forming the group may be substituted with a fluorine atom. 【Chemistry 6】 (X ４ is -CONH-, -NHCO-, -O-, -CH ２ O-, -OCH ２ represents -, -COO- or -OCO-. ３ represents a structure having a steroid skeleton.)

5. The polyimide varnish according to claim 4, wherein the diamine (a) is at least one diamine selected from the group consisting of the following formulas (V-1) to (V-13): 【Chemistry 7】 【Chemistry 8】 (In the above formula, X ｖ１ ~X ｖ４ , X ｐ１ ~X ｐ８ and each independently represent -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ represents -OCO-, -COO-, or -OCO-; X ｖ５ is -O-, -CH ２ represents —O—, —COO—, or —OCO—; X Ｖ６ ~X Ｖ７ , X ｓ１ ~X ｓ４ are each independently —O—, —CH ２ O-, -OCH ２ represents -, -COO- or -OCO-. ａ ~X ｆ are each independently a single bond, —O—, —NH—, or —O—(CH ２ ) ｍ -O-, -C(CH ３ ) ２ -, -CO-, -COO-, -CONH-, -(CH ２ ) ｍ -, -SO ２ -, -O-C(CH ３ ) ２ -, -CO-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -NH-, -SO ２ - (CH ２ ) ｍ -, -SO ２ - (CH ２ ) ｍ -SO ２ -, -CONH-(CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -NHCO- or -COO-(CH ２ ) ｍ represents —OCO—, and R ｖ１ ~R ｖ４ , R １ａ ~R １ｈ each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms; and m represents an integer of 1 to 8.

6. The polyimide varnish according to any one of claims 1 to 5, wherein the polyimide (A) has a ring-closed structure in which 20 to 90% of all repeating units contained in the polyimide precursor are ring-closed.

7. The polyimide varnish according to any one of claims 1 to 6, wherein the amine compound (B) is contained in an amount of 0.1 to 50 parts by mass per 100 parts by mass of the polyimide (A).

8. A liquid crystal aligning agent obtained from the polyimide varnish according to any one of claims 1 to 7.

9. The liquid crystal aligning agent according to claim 8, further comprising at least one other polymer selected from the group consisting of polyimide precursors, polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, and polymerizable unsaturated bond-containing monomer polymers.

10. The polymer of the monomer having a polymerizable unsaturated bond is obtained using at least one compound selected from the group consisting of (meth)acrylic compounds, (meth)acrylic acid amide compounds, aromatic vinyl compounds, conjugated diene compounds, maleimide group-containing compounds, α-methylene-γ-butyrolactone compounds, vinyl compounds other than aromatic vinyl compounds, and compounds containing a maleic anhydride structure, the liquid crystal aligning agent according to claim 9.

11. The polymer of the monomer having a polymerizable unsaturated bond is obtained using at least one monomer selected from the group consisting of a monomer represented by the following formula (S-mA), a monomer having a carboxy group and a polymerizable unsaturated bond, and a monomer having an epoxy skeleton and a polymerizable unsaturated bond, the liquid crystal aligning agent according to claim 9 or 10. 【Chemistry 9】 (P is a (meth)acryloyloxy group, a styryl group, a vinyloxy group (CH ２ =CH-O-), a maleimide group, and an α-methylene-γ-butyrolactone structure. X is a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -((CH ２ ) ａ１ -A １ ) ｍ１ - (a1 is an integer from 1 to 15, A １ represents an oxygen atom or —COO—, m １ is an integer of 1 to 2. １ When is 2, multiple a1 and A １ and each independently have the same definition as above.) or a group "-L-OCO-CR'=CR"-", provided that when P is a (meth)acryloyloxy group, a vinyloxy group (CH ２ =CH-O-), when X is a maleimide group, X represents a single bond or a divalent organic group bonded to P via a carbon atom. J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms, provided that at least one hydrogen atom possessed by the alicyclic hydrocarbon group and the aromatic hydrocarbon group is substituted with a substituent selected from the group consisting of a halogen atom, a halogen-atom-containing alkyl group, a halogen-atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, an alkenyl group having 3 to 10 carbon atoms, and a heteroatom-containing group in which a carbon-carbon bond possessed by any methylene group of the halogen-atom-containing alkyl group, halogen-atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group is interrupted by an oxygen atom. In the group "-L-OCO-CR'=CR"-", L is a single bond or -(B １ - (CH ２ ) ｂ１ ) ｍ’ - (b1 is an integer from 1 to 15. B １ represents a single bond, -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -COO- or -OCO-. ’ is an integer of 1 to 2. ’ When is 2, multiple b1 and B １ are each independently defined as above, and B １ At least one of the groups is not a single bond. R' and R" each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

12. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 8 to 11.

13. A liquid crystal display device comprising the liquid crystal alignment film according to claim 12.

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