WO2021171939A1 - Polyimide varnish - Google Patents

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

Polyimide varnish

The present invention relates to a polyimide varnish capable of suppressing hygroscopic whitening, which is suitable as a liquid crystal alignment agent or the like.

Polyimide is widely used as a protective material and insulating material in the electrical and electronic fields because of its high mechanical strength, heat resistance, and solvent resistance. Specifically, when used as an insulating film for a semiconductor, a polyimide film having a thickness of 1 to 10 μm is formed on a wiring-processed silicon substrate, and when used as a liquid crystal alignment film, a transparent electrode is attached. It is common to form a thin polyimide film on various support substrates, such as forming a polyimide film with a thickness of 0.05 to 0.2 μm on the transparent substrate. In order to form this polyimide film, a polyimide varnish in which polyimide is dissolved in an appropriate organic solvent is applied onto a substrate by a method such as spin coating, offset printing, gravure printing, flexographic printing, or inkjet printing to obtain a coating film. It is common to apply heat treatment.

Polyimide has excellent properties as various protective materials and insulating materials, but has a drawback of poor solubility in organic solvents. Therefore, when dissolving polyimide in an organic solvent, highly soluble organic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and hexamethylphosphoramide are generally used. It is used in. However, while these solvents have high solubility, they have a drawback of high hygroscopicity.

Therefore, when a film is obtained using a polyimide varnish containing these organic solvents, the obtained film tends to be easily affected by the environment in which the coating or the like is formed. In particular, when coating or the like is performed in a high humidity environment, there is a problem that the solubility of the composition decreases due to moisture absorption before the heat treatment, polyimide is precipitated, and the film becomes white (moisture absorption whitening). Further, even if the film that has undergone moisture absorption and whitening is dried or heated, there is a problem that the original characteristics of polyimide cannot be obtained, and there is a problem that the surface of the obtained film is roughened.
Further, when a film is obtained by flexographic printing using a polyimide varnish, the polyimide component is precipitated on the flexographic plate and printing foreign matter is generated, or the polyimide component is precipitated at the ejection head portion of the inkjet device and the head is clogged. In some cases, it may lead to defects in the process.

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

Japanese Unexamined Patent Publication No. 5-117587 International Publication (WO) Publication No. 2011/129414

In view of the above circumstances, an object of the present invention is that the moisture absorption and whitening phenomenon can be suppressed, the viscosity change is small, the storage stability is excellent, and foreign matter and clogging are less likely to occur when the film is obtained, and the obtained film is obtained. Is to provide a polyimide varnish suitable as a liquid crystal aligning agent or the like, which is less likely to cause surface roughness and can obtain the characteristics of the original polyimide material even when dried or heated.

As a result of diligent research to achieve the above problems, the present inventor has focused on the fact that the whitening can be eliminated by increasing the water solubility of the polyimide in the varnish, and in order to increase the water solubility of the polyimide, It has been found that the moisture absorption whitening phenomenon is suppressed by adding an amine compound having a secondary amino group or a tertiary amino group and having a specific cyclic group to the polyimide varnish. On the other hand, when the amine compound is a primary amine compound, it has been clarified that the viscosity of the varnish is not stable and the storage stability is remarkably deteriorated.

The present invention is based on the above findings, and has the following gist.
A polyimide varnish containing the following component (A) and component (B).
Component (A): Polyimide (A) which is an imidized product of a polyimide precursor.
Component (B): The molecule has any one of a secondary amino group or a tertiary amino group and a cyclic group of any one of a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group. The amine compound (B) in which the amino group is bonded to an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group.

According to the present invention, the moisture absorption and whitening phenomenon can be suppressed, the viscosity change is small, the storage stability is excellent, and foreign matter and clogging of the ejection head of the inkjet device are less likely to occur when obtaining the film, and the film can be obtained. As the film, a polyimide varnish is provided in which the occurrence of surface roughness is small and the characteristics of the original polyimide material can be obtained even when the film is dried or heated.
The mechanism by which the above effects of the present invention are obtained is not always clear, but it is considered that the following is one of the causes.
Generally, it is known that polyimide has low solubility, but in the case of partially imidized polyimide, carboxylic acid derived from tetracarboxylic acid dianhydride remains, so carboxylic acid and amine It is possible to improve the water solubility by forming a salt. By salt-forming the amine with the polyimide in this way, it is possible to suppress the precipitation of the polyimide when the polyimide varnish absorbs moisture.
On the other hand, since polyimide has abundant electrophilic carbonyl groups, it is susceptible to nucleophilic attack by nucleophiles such as aliphatic amine compounds. In particular, polyimide derived from aromatic tetracarboxylic dianhydride is considered to be more susceptible to nucleophilic attack of aliphatic amines because it has a planar structure and has few steric hindrances. Therefore, from the viewpoint of ensuring storage stability with little change in viscosity, it is preferable to use an alicyclic or aliphatic tetracarboxylic acid dianhydride as a raw material for polyimide, and an aliphatic amine can be obtained by using such an embodiment. The risk of nucleophilic addition to polyimide as a nucleating agent can be reduced, and a polyimide varnish with little change in viscosity and high storage stability can be obtained.
Further, from the viewpoint of ensuring storage stability with little change in viscosity, the basicity of the polyimide varnish is preferably low, and such an embodiment can reduce the decrease in the molecular weight of the polyimide and the decrease in the viscosity of the polyimide varnish. can.
The amine compound of the present invention having either one of a secondary amino group or a tertiary amino group in the molecule is unlikely to undergo nucleophilic attack due to its large steric hindrance, but is a salt of an amine and a carboxylic acid. Since the formation occurs, it is considered that the precipitation of the polyimide varnish due to moisture absorption can be suppressed.
The polyimide varnish of the present invention is suitable as a protective material, an insulating material, etc. represented by a liquid crystal alignment agent.

<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 polyimide (A) can be used alone or in combination of two or more.
The polyimide precursor produces polyimide by an imidization reaction of a polyamic acid, a polyamic acid ester, etc. Among them, a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride or a derivative thereof and a diamine component. It is preferably a polyamic acid obtained by a (polycondensation) reaction. Examples of the derivative of the tetracarboxylic dianhydride include a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid diester dichloride, and a tetracarboxylic acid diester.

As the tetracarboxylic dianhydride or a derivative thereof, various tetracarboxylic dianhydrides or derivatives thereof can be used. Examples of the tetracarboxylic dianhydride or a derivative thereof include aromatic, acyclic aliphatic or alicyclic tetracarboxylic dianhydride, and 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 the 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 have to be composed of only a chain hydrocarbon structure, and a part thereof may have an alicyclic structure or an aromatic ring structure. The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to the alicyclic structure. However, none of these four carboxy groups are bonded to the aromatic ring. Further, it is not necessary to have only an alicyclic structure, and a chain hydrocarbon structure or an aromatic ring structure may be partially provided.

In the present invention, from the viewpoint of ensuring storage stability with little change in viscosity, it is preferable to use an acyclic aliphatic or alicyclic tetracarboxylic dianhydride or a derivative thereof as the tetracarboxylic acid derivative component. Above all, it is more preferable to contain a tetracarboxylic dianhydride 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, or a derivative thereof. The amount used is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, based on 1 mol of the total tetracarboxylic acid derivative component used. When the tetracarboxylic dianhydride contains the tetracarboxylic dianhydride and a tetracarboxylic dianhydride other than these derivatives, or a derivative thereof, the upper limit thereof is preferably 95 mol% or less, 90 More preferably, it is mol% or less.

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

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

In the above formulas (x-1) to (x-13), R ¹ to R ⁴ independently contain a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a fluorine atom, and a fluorine atom. It represents a monovalent organic group having 1 to 6 carbon atoms or a phenyl group. R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. j and k are independently integers of 0 or 1, and A ₁ and A ₂ are independent, single bond, -O-, -CO-, -COO-, phenylene, sulfonyl group, respectively. Or represents an amide group. * 1 is a bond that binds to one acid anhydride group, and * 2 is a bond that binds to the other acid anhydride group. The two A _2s may be the same or different.
Among them, it is preferable that X is any one of the above formulas (x-1) to (x-7) and (x-11) to (x-13).

More preferable specific examples of the above formula (x-1) include the following formulas (x1-1) to (x1-6). In the formula, * represents a bond.

The proportion of the tetracarboxylic dianhydride or its derivative represented by the above formula (3) is preferably 1 mol% or more, more preferably 5 mol% or more, based on 1 mol of the tetracarboxylic acid component used. More preferably, it is 10 mol% or more. When the tetracarboxylic acid derivative contains a tetracarboxylic dianhydride represented by the above formula (3), a tetracarboxylic dianhydride other than these derivatives, or a derivative thereof, the upper limit thereof is set. 95 mol% or less is preferable, and 90 mol% or less is more preferable.
The tetracarboxylic dianhydride or a derivative thereof may be used alone or in combination of two or more.

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

In the above formula (S1), X ¹ and X ² are independently single-bonded, − (CH ₂ ) _a − (a is an integer of 1 to 15), −CONH−, −NHCO−, respectively. Represents -CON (CH ₃ )-, -NH-, -O-, -COO-, -OCO-, or-((CH ₂ ) _a1- A ₁ ) _m1- . Of these, a1 is an integer of 1 to 15, A ₁ represents an oxygen atom or -COO-, and m ₁ is 1 to 2. From the viewpoint of availability of raw materials and ease of synthesis, X ₁ and X ₂ are independently single-bonded,-(CH ₂ ) _a- (a is an integer of 1 to 15),-. O-, -CH ₂ O- or -COO- are preferred, single bonds,-(CH ₂ ) _a- (a is an integer of 1-10), _{-O-, -CH 2} O- or -COO. -Is more preferable.

G ₁ and G ₂ 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 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, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. Alternatively, it may be substituted with a fluorine atom. m and n are independently integers of 0 to 3, and the total of m and n is 1 to 6, preferably 1 to 4.
Among these, examples of the divalent aromatic group having 6 to 12 carbon atoms include phenylene, a biphenyl structure, naphthalene and the like. Examples of divalent alicyclic groups having 3 to 8 carbon atoms include cyclopropylene and cyclohexylene.

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. Any hydrogen atom forming R ¹ may be substituted with a fluorine atom.
If there are two or more X ¹ , X ² , G ¹ , G ² , a 1, and A ₁ ^{, the two or more X 1} , X ² , G ¹ , G ² , a 1, and A ₁ are independent of each other. It may be the same or different.

Preferred specific examples of the above formula (S1) include the following formulas (S1-x1) to (S1-x7).

In the formulas (S1-x1) to (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-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-, -NH-, -O- _{, -CH 2 O-} , -CH ₂ OCO-, -COO-, or -OCO-, where A ₁ is an oxygen atom or -COO- * (however, the bond with "*" binds to (CH ₂ ) a ₂ ). , A ₂ are oxygen atoms or * -COO- (where the bond with "*" binds to (CH ₂ ) a ₂ ), and a ₁ and a ₃ are independently 0 or It is an integer of 1, a ₂ is an integer of 1 to 10, and Cy is a 1,4-cyclohexylene group or a 1,4-phenylene group.

In the above formula (S2), X ³ is a single bond, _{-CONH-, -NHCO-, -CON (CH 3} )-, _{-NH-, -O-, -CH 2} O-, -COO- or -OCO-. Represents. _{Among them, -CONH-, -NHCO-, -O-, -CH 2} O-, -COO- or -OCO- are preferable from the viewpoint of liquid crystal orientation.
R ² represents an alkyl group having 1 to 20 carbon atoms or an alkoxy alkyl group having 2 to 20 carbon ^{atoms, and any hydrogen atom forming R 2} may be substituted with a fluorine atom. Among them, an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is preferable from the viewpoint of liquid crystal orientation.

In a preferred embodiment of the formula [S2], X ³ is any of -O-, -CH ₂ O-, -COO- or -OCO-, and R ² is an alkyl group having 3 to 20 carbon atoms or an alkyl group having 20 carbon atoms. preferably represents an alkoxyalkyl group of 2 to 20, more preferably when R ² is an alkyl group having 3 to 20 carbon atoms, any hydrogen atoms that form the R ² may be substituted by fluorine atoms ..

In the above formula (S3), X ⁴ represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -OCH _{2-, -COO- or -OCO-.}
R ³ represents a structure having a steroid skeleton, and specific examples thereof include a structure having a skeleton represented by the following formula (st).

An example of the above formula (S3) is the following formula (S3-x).

In the formula (S3-x), X represents the above formulas (X1) (X2) or (X3). Further, Col represents one kind selected from the group consisting of the above formulas (Col1) to (Col4), and G represents the above formula (G1) or (G2). * Represents a site that binds to another group.
As a more preferable structure of the formula (S3), the structures represented by the following formulas (S3-1) to (S3-6) can be mentioned.

(* Indicates the connection position)

Specific examples of the specific diamine include the diamines of the following formulas (V-1) to (V-13).

In the formula, X ^v1 to X ^v4 and X ^p1 to X ^p8 are independent _{of-(CH 2} ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-,-. _{CON (CH 3) -, -} NH -, - O -, - CH 2 O -, - CH 2 OCO -, - COO-, or -OCO- ^{indicates, X v5} is -O -, - _CH 2 O- , -CH ₂ OCO-, -COO-, or -OCO-, and X ^V6 to X ^V7 and X ^s1 to X ^s4 are independently -O-, -CH ₂ O-, -OCH _2- , Indicates -COO- or -OCO-. X _a to X _f are independently single-bonded, -O-, -NH-, -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 ) _{indicates m-} NHCO- or -COO- (CH ₂ ) _m- OCO-, and R ^v1 to R ^v4 and R ^1a to R ^1h are independently alkyl groups 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 is shown. m represents an integer from 1 to 8.

The content of the specific diamine is preferably 5 to 95 mol%, more preferably 5 to 90 mol%, and 5 to 80 mol% with respect to the entire diamine component from the viewpoint of imparting liquid crystal orientation. Especially preferable.

The above-mentioned specific diamine can be used alone or in combination of two or more.

<Other diamines>
As the diamine for obtaining the polyamic acid, a diamine other than the above-mentioned specific diamine (also referred to as other diamine) may be used. In addition, other diamines can 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,

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'-diamino Diphenylamine, 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-amino) Phenyl) ethane, 1,2-bis (3-aminophenyl) ethane, 1,3-bis (4-aminophenyl) propane,

1,3-bis (3-aminophenyl) propane, 1,4-bis (4-aminophenyl) butane, 1,4-bis (3-aminophenyl) butane, bis (3,5-diethyl-4-amino) Phenyl) methane, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyloxy) 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-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 [(4-4-phenylenebis) Aminophenyl) methanone], 1,4-phenylenebis [(3-aminophenyl) methanone], 1,3-phenylenebis [(4-aminophenyl) methanone], 1,3-phenylenebis [(3-aminophenyl) ) Metanon], 1,4-phenylenebis (4-aminobenzoate), 1,4-phenylenebis (3-aminobenzoate), 1,3-phenylenebis (4-aminobenzoate),

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-amino) Phenyl) anthracene, 4,4'-bis (4-aminophenoxy) diphenylsulfone, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-bis [4- (4- (4- (4- (4-)4-) Aminophenoxy) Phenyl] Hexafluoropropane, 2,2'-bis (4-aminophenyl) hexafluoropropane, 2,2'-bis (3-aminophenyl) hexafluoropropane, 2,2'-bis (3-aminophenyl) 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,

1,5-bis (4-aminophenoxy) pentane, 1,5-bis (3-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane, 1,6-bis (3-aminophenoxy) ) Hexan, 1,7-bis (4-aminophenoxy) heptane, 1,7- (3-aminophenoxy) heptane, 1,8-bis (4-aminophenoxy) octane, 1,8-bis (3-aminophenoxy) Aminophenoxy) octane, 1,9-bis (4-aminophenoxy) nonane, 1,9-bis (3-aminophenoxy) nonan, 1,10-bis (4-aminophenoxy) diamine, 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 (hn-1) to (nh-8), diamines represented by the following formulas (z-1) to (z-14), the following formulas (z-1) Diamines having a radical initiation function such as diamines represented by R1) to (R5), and groups such as diamines represented by the following formulas (5-1) to (5-11) "-N (D)-" ( D represents a protective group desorbed by heating and replaced with a hydrogen atom, preferably a tert-butoxycarbonyl group), a diamine represented by the following formulas (Dp-1) to (Dp-6), and a methacryl. Aromatic diamines such as 2- (2,4-diaminophenoxy) ethyl acid and diamines having photopolymerizable groups such as 2,4-diamino-N, N-diallylaniline at the ends, bis (4-aminocyclohexyl) methane , Alicyclic diamines such as bis (4-amino-3-methylcyclohexyl) methane, 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, 1,12-diaminododecane and other aliphatic diamines.

(In equations (R3) to (R5), n is an integer of 2 to 6.)

(Boc represents a tert-butoxycarbonyl group.)

The method for obtaining a polyamic acid from the tetracarboxylic acid component and the diamine component is performed 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 at that time is not particularly limited as long as it dissolves the produced polyamic acid.
Specifically, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-2- Examples include imidazolidinone. When the solvent solubility of the polyamic acid is high, a solvent of methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone or the following formulas [D1] to [D3] can be used. ..

(D ¹ and D ² indicate an alkyl group having 1 to 3 ^{carbon atoms. D 3} indicates an alkyl group having 1 to 4 carbon atoms.)
These organic solvents may be used alone or in combination. Further, even if the solvent does not dissolve the polyamic acid, it may be mixed with the above solvent and used as long as the produced polyamic acid does not precipitate.

The concentration of the polyamic acid in the reaction system is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polyamic acid is unlikely to occur and a high molecular weight substance is easily obtained.
The polyamic acid obtained as described above can be precipitated and recovered by injecting the reaction solution into a poor solvent while stirring well. Further, the purified polyamic acid powder can be obtained by performing precipitation several times, washing with a poor solvent, and then drying at room temperature or by heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.
The polyamic acid ester can be obtained, for example, by subjecting the polyamic acid to an esterification reaction with an esterifying agent.

The polyimide (A) contained in the polyimide varnish of the present invention can be obtained by imidizing a polyimide precursor such as the polyamic acid or polyamic acid ester. In the polyimide (A), the repeating unit of the polyimide precursor is ring-closed, but the ratio of the repeating unit to be ring-closed to all the repeating units of the polyimide precursor (also referred to as ring closure rate or imidization rate) is not always the case. It does not have to be 100%, preferably 20 to 90%, more preferably 30 to 80%, and in this range, it can be arbitrarily adjusted according to the use and purpose of the polyimide varnish.
When the polyimide varnish of the present invention is a liquid crystal alignment agent for forming a liquid crystal alignment film, the imidization ratio is preferably 20 to 95%, more preferably 30 to 95%.

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. As the organic solvent, the organic solvent used in the above-mentioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, pyridine is preferable because it has an appropriate basicity for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like. Among them, acetic anhydride is preferable because it facilitates purification after the reaction is completed.

The temperature at which the imidization reaction is carried out 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 mol times, preferably 2 to 20 mol times, that of the amic acid, and the amount of the acid anhydride is 1 to 50 mol times, preferably 3 to 30 mol times that of the amic acid. It is double. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, the temperature, and the reaction time.
Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid, the obtained polyimide is recovered by the means described below and redissolved in an organic solvent to align the liquid crystal display of the present invention. It is preferably used as a component of the agent.
The polyimide solution obtained as described above can be injected into a poor solvent with good stirring to precipitate a polymer. The precipitate can be separated by filtration, washed with a poor solvent several times, and then dried at room temperature or by heating to obtain a purified polyimide powder.

The molecular weight of the polyimide obtained as described above was measured by the GPC (Gel Permeation Chromatography) method in consideration of the strength of the film obtained from the polyimide varnish obtained from the polyimide varnish, the workability at the time of film formation, and the coating property. The weight average molecular weight (Mw) is preferably 2,000 to 1,000,000, more preferably 10,000 to 150,000. The number average molecular weight (Mn) is preferably 3,000 to 100,000, more preferably 10,000 to 50,000.

<Amine compound (B)>
The polyimide varnish of the present invention contains the following component (B).
Component (B): The molecule has any one of a secondary amino group or a tertiary amino group and a cyclic group of any one of a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group. The amine compound (B) in which 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).

In the above formula (1), R ₁ and R ₂ independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and at least one of _{R 1} and R _{2 is an alkyl having 1 to 5 carbon atoms.} Represents a group.
The alkyl group having 1 to 5 carbon atoms may be linear or branched. 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 or a pentyl group.
Ar represents a monovalent group having a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group. The hydrogen atom on the nitrogen-containing aromatic heterocycle of Ar or the hydrogen atom of the aromatic hydrocarbon group is an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, or a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine). It may be replaced with an atomic group), a halogen atom-containing alkyl group, a halogen atom-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], which is more preferable. Is a cyclic structure containing 1 to 4 of the above partial structures.

(In the formula, Y ₁ is a linear or branched alkyl group having 1 to 5 carbon atoms).

More preferred examples of the nitrogen-containing aromatic heterocycle are pyrol ring, imidazole ring, oxazole ring, thiazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazoline ring, isoquinoline ring, benzazole ring, purine ring, thiaziazole. Examples thereof include a ring, a pyridazine ring, a triazine ring, a triazole ring, a pyrazine ring, a benzimidazole ring, a phenanthroline ring, an indole ring, a quinoxalin ring, a benzothiazole ring, a phenothiazine ring, an oxaziazole ring, and an axidine ring.
In addition, preferable 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 non-aromatic cyclic hydrocarbon groups include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptan ring, cyclooctane ring, cyclononane ring, cyclodecane ring, cycloundecane ring, cyclododecane ring, and the like. Cyclotridecane ring, cyclotetradecane ring, cyclopentadecane ring, cyclohexadecane ring, cycloheptadecane ring, cyclooctadecane ring, cyclononadecane ring, cycloicosane ring, tricycloeikosan ring, bicycloheptane ring, decahydronaphthalene ring, norbornene ring, Examples thereof include an alicyclic hydrocarbon group having 3 to 20 carbon atoms such as an Adamantane ring.

Among them, X is preferably a group represented by _{* 1-X 1-} X _2- * 2 for the reason of ease of synthesis and availability of raw materials.
However, X ₁ represents a divalent group containing an acyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms or a non-aromatic cyclic hydrocarbon group. X ₁ is preferably a divalent acyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms or a non-aromatic cyclic hydrocarbon group. Preferred examples of acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group of X ₁ are the same as examples of X described above.
X ₂ is a single bond, -O-, -NH-, -S-, -SO _2- or a divalent organic group having 1 to 19 carbon atoms. The total number of carbon atoms contained in X ₁ and X ₂ is 1 to 20, preferably 1 to 10.
Note that * 1 is a bond that binds to N in the formula (1), and * 2 is a bond that binds to Ar in the formula (1).

N to which R ₁ and R ₂ are bonded is bonded to the acyclic aliphatic hydrocarbon group or the non-aromatic cyclic hydrocarbon group.

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

The amine compound (B) is one or more of the compounds represented by any of the above formulas (b-1) to (b-3) because of the difficulty of production and the availability of raw materials. Is preferable.

<Polyimide varnish>
The polyimide varnish of the present invention contains the polyimide (A) which is the component (A) and the amine compound (B) which is the component (B). Polyimide varnish is obtained, for example, by dispersing or dissolving these components in an organic solvent.
The total content of the polyimide (A) in the polyimide varnish is preferably 1 to 20% by mass, more preferably 1 to 15% by mass, and 1 to 10 from the viewpoint that it is easy to uniformly mix with the compound (B). Mass% is particularly preferred.
Further, the content of the amine compound (B) which is the component (B) in the polyimide varnish is 100 parts by mass of the polyimide (A) from the viewpoint that the effect of the present invention can be efficiently obtained and the stability of the polyimide varnish is enhanced. On the other hand, it 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.

The organic solvent that may be contained in the polyimide varnish of the present invention is one that disperses or dissolves the polyimide (A) that is the component (A) and the amine compound (B) that is the component (B), preferably. Things are used.
Examples of the organic solvent include lactone solvents such as γ-valerolactone and γ-butyrolactone, lactam solvents such as γ-butylolactam, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, and N, N-dimethylformamide. , N, N-dimethylacetamide, N, N-dimethylpropionamide, tetramethylurea, N, N-diethylformamide and other amide solvents; 4-hydroxy-4-methyl-2-pentanone, diisobutylketone (2,6- Dimethyl-4-heptanone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, 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; Solvent of carbonates such as ethylene carbonate and propylene carbonate Examples thereof include medium, 1-hexanol, cyclohexanol, 1,2-ethanediol, diisobutylcarbinol (2,6-dimethyl-4-heptanol), cyclohexanone, cyclopentanone and the like.

When two or more kinds of organic solvents are used, preferred combinations are N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, ethylene glycol mono-n-butyl ether, and 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 and 4-hydroxy-4-methyl-2- Pentanone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl- 2-Pentanone and diisobutylketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2 -Pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl Ketone, γ-butylolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylketone, N-methyl-2-pyrrolidone And γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutylcarbinol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether , N-Methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone and ethylene glycol monobutyl ether acetate Dipropylene glycol dimethyl ether, N, N-dimethylpropionamide and Examples thereof include lopyrene glycol diacetate, tetramethylurea and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone and propylene glycol monomethyl ether, and cyclopentanone and propylene glycol monomethyl ether.

The polyimide varnish of the present invention can contain various components (also referred to as other components) depending on its use, in addition to the polyimide (A) and the component (B) described above (A). For example, polymers other than the above-mentioned polyimide (A), antioxidants (phenolic, phosphite, thioether, etc.), ultraviolet absorbers, hindered amine light stabilizers, nucleating agents, resin additives (fillers, talc). , Glass fiber, etc.), flame retardants, processability improvers, lubricants, etc.

<Liquid crystal alignment agent>
In the case of the liquid crystal alignment agent, which is a preferred application of the polyimide varnish of the present invention, it is preferable that the liquid crystal alignment agent is prepared so as to be suitable for forming a liquid crystal alignment film. The liquid crystal alignment agent of the present invention preferably contains the polyimide varnish of the present invention.
The liquid crystal alignment agent of the present invention can be obtained, for example, by dispersing or dissolving the polyimide varnish of the present invention and other components, if necessary, in an organic solvent. Further, the liquid crystal alignment agent of the present invention may be obtained by mixing two or more kinds of liquid crystal alignment agents. For example, it may be obtained by mixing two or more kinds of liquid crystal alignment agents containing the polyimide varnish of the present invention, and the liquid crystal alignment agent containing the polyimide varnish of the present invention and the liquid crystal alignment agent containing other components are mixed. It may be obtained by doing. 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 and the like. ..

Other polymers are not particularly limited, and are, for example, polyimide precursors such as polyamic acid and polyamic acid ester, polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polyacetal, and monomers having a polymerizable unsaturated bond. Examples thereof include the polymer of. As the other polymer, a polymer of a monomer having a polymerizable unsaturated bond is preferably used. As for other polymers, one type may be used alone, or two or more types may be used in combination.
When other polymers are used, the usage ratio is preferably 50% by mass or less, more preferably 0.1 to 40% by mass, and further, based on the total amount of the polymers contained in the polyimide varnish. It is preferably 0.1 to 30% by mass.

Examples of the monomer having a polymerizable unsaturated bond include (meth) acrylic compounds (including unsaturated carboxylic acids, unsaturated carboxylic acid esters and unsaturated polyvalent carboxylic acid anhydrides), and (meth) acrylic acid amides. Examples thereof include system 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 the polymer of the compound containing a maleic anhydride structure include poly (styrene-maleic anhydride) copolymer, poly (isobutylene-maleic anhydride) copolymer, and poly (vinyl ether-maleic anhydride). Examples include polymers. Specific examples of the poly (styrene-maleic anhydride) copolymer include SMA1000, 2000, 3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Cellac), and the like, and poly (isobutylene-maleic anhydride). ) Specific examples of the copolymer include Isoban-600 (manufactured by Kuraray), and specific examples of the poly (vinyl ether-maleic anhydride) copolymer include GANTREZ AN-139 (methyl vinyl ether maleic anhydride resin). , Made by ISP Japan).

In the polymer of the (meth) acrylic compound (hereinafter, also referred to as polymer (uA)), the ratio of the (meth) acrylic compound used is 50 mol% with respect to the total amount of the monomers used for the synthesis. It may be more than or equal to 60 mol% or more.

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

Examples of the monomer for obtaining the polymer (uA) include a monomer represented by the following formula (S-mA), a monomer having a polymerizable unsaturated bond with a carboxy group, a monomer having a polymerizable unsaturated bond with an epoxy skeleton, and a monomer having a polymerizable unsaturated bond with an epoxy skeleton. Other monomers having a polymerizable unsaturated bond may be used.

(P represents 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-, and m ₁ is 1-2. for .m ₁ is 2 is an integer multiple of a1 and _{a 1} are each independently have the above definitions), or a group - represents "-L-OCO-CR '= CR "'. However, when P is a (meth) acryloyloxy group, a vinyloxy group (CH ₂ = CH—O—), or a maleimide group, X represents a single bond or a linking group that is bonded to P via a carbon atom.
J represents a monovalent organic group having at least one group selected from the group consisting of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms. At least one of the hydrogen atoms contained in the alicyclic hydrocarbon group and the aromatic hydrocarbon group is a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, and 3 carbon atoms. The carbon-carbon bond contained in an alkoxy group of ~ 10 and an alkenyl group having 3 to 10 carbon atoms, and any methylene group of the halogen atom-containing alkyl group, halogen atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group. It is substituted with a substituent selected from the group consisting of heteroatomic groups interrupted by oxygen atoms. )
It should be noted that two groups of at least one selected from the group in which J in the above formula (S-mA) consists of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms. In the case of the monovalent organic group having the above, it is sufficient that at least one alicyclic hydrocarbon group or an aromatic hydrocarbon group has the above substituent, and the other group of J of the above formula (S-mA) has. The alicyclic hydrocarbon group or aromatic hydrocarbon group may have substituents or substituents other than those exemplified above.
In the group "-L-OCO-CR'= CR"-", L is a single bond or-(B _1- (CH ₂ ) _b1 ) _m' -(b1 is an integer of 1 to 15. B ₁ represents a single _{bond, -CONH -, - NHCO -,} - CON (CH 3) -, - NH -, - O -, - .m representing the COO- or -OCO- ^'is an integer of 1 to 2. If m ^'is 2, a plurality of b1 and B ₁ each independently have the above definitions, at least one of B ₁ represents represents a 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.

As a more preferable specific example of the above group "-XJ", a group represented by any of the following formulas (S1) to (S2) can be mentioned.

(X ¹ is a single bond,-(CH ₂ ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH ₃ )-, -NH-, -O -, -COO-, -OCO-,-((CH ₂ ) _a1- A ₁ ) _m1- (a1 is an integer from 1 to 15. A ₁ represents an oxygen atom or -COO-, and m ₁ is 1. If ~ .m ₁ is a 2 integer is 2, the plurality of a1 and _{a 1} have each independently as defined above), or a group. - represents "-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 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, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. Alternatively, it may be substituted with a fluorine atom. However, m is an integer of 1 to 4. When m is 2 or more, the plurality of X ¹ and G ¹ have the above definitions independently.
R ¹ is 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 carbon. Represents the number 3 to 10 alkoxyalkyl groups.
In the group "-L-OCO-CR'= CR"-", L is a single bond or-(B _1- (CH ₂ ) _b1 ) _m' -(b1 is an integer of 1 to 15. B ₁ represents a single _{bond, -CONH -, - NHCO -,} - CON (CH 3) -, - NH -, - O -, - .m representing the COO- or -OCO- ^'is an integer of 1 to 2. If m ^'is 2, a plurality of b1 and B ₁ each independently have the above definitions, at least one of B ₁ represents represents a represents.) a linking group other than a single bond.
In the group "-L-OCO-CR'= CR"-", the above R'and R" represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

(X ² represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -OCH _2- ^{, -COO- or -OCO-. G 2} represents a structure having a steroid skeleton. At least one of the hydrogen atoms in the structure having a steroid skeleton is 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, and a carbon number of carbon atoms. A hetero in which the carbon-carbon bond of 3 to 10 alkenyl groups and 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. It is substituted with a substituent selected from the group consisting of atomic-containing groups.)

In the above formula (S1) ^{, examples of the divalent cyclic group in G 1} include a cyclopropylene group, a cyclohexylene group, and a phenylene group. Any hydrogen atom on these cyclic groups can be 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, or a fluorine-containing alkoxy group having 1 to 3 carbon atoms. It may be substituted with a group or a fluorine atom.

In the above formula (S2), ^{examples of the structure having a steroid skeleton in G 2} include a structure containing a cholestanyl group, a cholesteryl group or a lanostenyl group.

Specific examples of the monomer having a carboxy group and a polymerizable unsaturated bond include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-hydroxyethyl (meth) acrylic acid, and 2-carboxyethyl. Carboxy group-containing (meth) acrylate compounds such as (meth) acrylate, 2-carboxypropyl (meth) acrylate, 5-carboxypentyl (meth) acrylate, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid; 4 -Vinyl group-containing aromatic carboxylic acid such as vinyl benzoic acid; 4-maleimide carboxy group-containing maleimide such as benzoic acid; N- (carboxyphenyl) methacrylicamide, and carboxy group-containing (meth) such as N- (carboxyphenyl) acrylamide. ) Acrylamide compounds can be mentioned.

Examples of the monomer having a polymerizable unsaturated bond with the epoxy skeleton include allyl glycidyl ether, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, glycidyl α-ethyl (meth) acrylate, and α-n-. Glycidyl propyl (meth) acrylate, glycidyl α-n-butyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 6,7-epoxyheptyl (meth) acrylate, o-vinylbenzyl glycidyl ether , M-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, (meth) acrylic acid 3,4-epoxycyclohexylmethyl, 3-ethenyl-7-oxabicyclo [4.1.0] heptane, 1,2- Epoxy-5-hexene and 1,7-octadienmonoepoxiside can be mentioned.

Examples of the above-mentioned monomer having a polymerizable unsaturated bond include the following monomers.

Amino group-containing (meth) acrylate compounds such as aminoethyl (meth) acrylate and aminopropyl (meth) acrylate;
Hydroxymethyl group or alkoxymethyl group-containing (meth) acrylamide compound such as N-hydroxymethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc. ;
3- (Acryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) oxetane, 3- (acryloyloxymethyl) -2-methyloxetane, 3- (methacryloyloxymethyl) -2-methyloxetane, 3- (acryloyloxymethyl) )-3-Ethyloxetane, 3- (methacryloyloxymethyl) -3-ethyloxetane and other compounds having an oxetane skeleton;
Nitrogen-containing aromatics such as 2- (2-pyridylcarbonyloxy) ethyl (meth) acrylate, 2- (3-pyridylcarbonyloxy) ethyl (meth) acrylate, 2- (4-pyridylcarbonyloxy) ethyl (meth) acrylate Compounds with heterocycles;
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- (Meta) acrylic acid ester compounds such as ethyl-8-tricyclodecyl (meth) acrylate;
(Meta) acrylic acid amide compounds such as acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide;
Vinyl ether compounds such as methyl vinyl ether, benzyl vinyl ether, vinylnaphthalene, vinylcarbazole; aromatic vinyl compounds such as styrene, methylstyrene, chlorostyrene, and bromostyrene; maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexyl. Maleimide group-containing compounds such as maleimide.

As the monomer component for obtaining the polymer (uA), it is represented by the above-mentioned carboxy group and the monomer having a polymerizable unsaturated bond, the above-mentioned monomer having the epoxy skeleton and the above-mentioned polymerizable unsaturated bond, and the above formula (S-mA). The total amount of the monomers is preferably 10 mol% or more, and preferably 20 mol% or more. When the other monomer having a polymerizable unsaturated bond is used in combination, the total amount of the monomer having a carboxy group and the polymerizable unsaturated bond and the monomer represented by the above formula (S-mA) is 99 mol% or less. It is preferably 95 mol% or less, and more preferably 90 mol% or less.

As for the molecular weight of the polymer (uA) obtained as described above, the weight average molecular weight (Mw) measured by the GPC (Gel Permeation Chromatography) method is preferably 2,000 to 1,000,000, which is more preferable. Is 10,000 to 150,000. The number average molecular weight (Mn) is preferably 3,000 to 100,000, more preferably 10,000 to 50,000.

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 the compounds having a hydroxyalkylamide bond and the compounds having an alkoxyalkylamide bond described in Japanese Patent Application Laid-Open No. 2016-118753 and WO2015 / 156314, and WO2016 / 047771 [0109] to [0113]. In addition to the above-mentioned compounds having at least one group selected from the group consisting of epoxy groups, oxetane groups, hydroxy groups, hydroxyalkyl groups, isocyanate groups, cyclocarbonates, and lower alkoxyalkyl groups, compounds having blocked isocyanate groups. And so on.

Examples of the compound having an epoxy group include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1 , 6-Hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, Epicoat 828 (Mitsubishi Chemical Co., Ltd.) Bisphenol A type epoxy resin such as Epicoat 807 (manufactured by Mitsubishi Chemical Co., Ltd.), hydrogenated bisphenol A type epoxy resin such as YX-8000 (manufactured by Mitsubishi Chemical Co., Ltd.), YX6954BH30 (manufactured by Mitsubishi Chemical Co., Ltd.) Biphenyl skeleton-containing epoxy resin such as EPPN-201 (manufactured by Nippon Explosives Co., Ltd.), phenol novolac type epoxy resin such as EPPN-201 (manufactured by Nippon Explosives Co., Ltd.), (o, m, p-) cresol novolac type epoxy such as EOCN-102S (manufactured by Nippon Explosives Co., Ltd.) Resin, triglycidyl isocyanurate such as TEPIC (manufactured by Nissan Chemical Co., Ltd.), alicyclic epoxy resin such as celloxide 2021P (manufactured by Daicel Chemical Industry Co., Ltd.), N, N, N', N'-tetraglycidyl-m-xylylene Amin, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-4, 4'-diaminodiphenylmethane, and tetrakis (glycidyloxymethyl) methane are preferable.

Blocked isocyanate compounds are available as commercial products, for example, Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B. -815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.) and the like can be preferably used.

Specific examples of the preferable crosslinkable compound include compounds represented by the following formulas (CL-1) to (CL-11).

The above is an example of a crosslinkable compound, and the present invention is not limited thereto. Further, two or more kinds of crosslinkable compounds used in the liquid crystal alignment agent of the present invention may be combined.

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 1 to 50 parts by mass with respect to 100 parts by mass of all the polymer components. Part is particularly preferable.
The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the underlying substrate. As a specific example, the silane compound described in paragraph [0019] of International Publication 2014/119682 can be mentioned. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, and more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of all the polymer components.

The surfactant can be used to improve the film thickness uniformity and surface smoothness of the liquid crystal alignment film. Examples of the surfactant include a fluorine-based surfactant, a silicone-based surfactant, and a nonion-based surfactant. Specific examples of these include those described in [0117] of WO2016 / 047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of the total polymer contained in the liquid crystal alignment agent.
The compound having a photopolymerizable group is a compound having one or more polymerizable unsaturated groups such as an acrylate group and a methacrylate group in the molecule, for example, one of the following formulas (M-1) to (M-7). Examples include the compounds represented.

As the organic solvent that may be contained in the liquid crystal alignment agent, the solvent described in the polyimide varnish can be used, and the type and content of the solvent are appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent. Will be done.
The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the organic solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferable. Is 1 to 10% by mass.

A particularly preferable solid content concentration varies depending on the method used when applying the liquid crystal alignment agent to the substrate. For example, in the case of the spin coating method, 1 to 10% by mass is particularly preferable. In the case of the printing method, it is particularly preferable that the solution viscosity is 3 to 9% by mass, whereby the solution viscosity is 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solution viscosity is 1 to 5% by mass, whereby the solution viscosity is 3 to 15 mPa · s.

The liquid crystal alignment agent can be used as a liquid crystal alignment film by applying it on a substrate, firing it, and then performing an alignment treatment by rubbing treatment, light irradiation, or the like. Further, in the case of vertical alignment applications, it can be used as a liquid crystal alignment film without 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, a PET (polyethylene terephthalate) substrate, and a film thereof can be used. Can be used. From the viewpoint of process simplification, a substrate on which an ITO electrode for driving a liquid crystal display, a metal electrode such as an IZO (Indium Zinc Oxide) electrode and an IGZO (Indium Gallium Zinc Oxide) electrode, and an organic conductive film are formed. Is preferably used. Further, in the case of a reflective liquid crystal display element, if only one substrate is used, a substrate on which a metal such as a silicon wafer or aluminum or a dielectric multilayer film is formed can be used.

The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method such as screen printing, offset printing, flexographic printing, or an inkjet method is generally used. Other coating methods include a dip method, a roll coater method, a slit coater method, a spin coating method, a spray method, and the like, and these may be used depending on the intended purpose.
After applying the liquid crystal aligning agent on the substrate, the temperature is 30 to 300 ° C., preferably 30 depending on the solvent used for the liquid crystal aligning agent by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. The solvent is evaporated at a temperature of about 250 ° C. to form a liquid crystal alignment film.

If the thickness of the liquid crystal alignment film after firing is too thick, it is disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, it is preferably 5 to 300 nm, more preferably. Is 10 to 200 nm.
When the liquid crystal is horizontally or inclined, the liquid crystal alignment film after firing is treated by rubbing or irradiation with polarized ultraviolet rays.
As the ultraviolet rays, ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. As the light source of the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser and the like can be used. The ultraviolet rays in the preferred wavelength region can be obtained by means of using the light source in combination with, for example, a filter or a diffraction grating. The amount of light irradiation is preferably 1,000 J / m ² or more and less than 100,000 J / m ² , and more preferably 1,000 to 50,000 J / m ² .
The liquid crystal used for the liquid crystal display element is not particularly limited, and for example, a nematic liquid crystal, a smectic liquid crystal, or a cholesteric liquid crystal can be used. At that time, a liquid crystal having positive or negative dielectric anisotropy can be selected depending on the method of the liquid crystal display element. It is also possible to dissolve a dichroic dye in the liquid crystal to form a guest host type liquid crystal display element.
The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be used as a liquid crystal alignment film for a horizontally or vertically oriented liquid crystal display element.
The liquid crystal alignment film for a horizontally oriented liquid crystal display element is suitable as a liquid crystal display element of a transverse electric field type such as an IPS system or an FFS system, or a liquid crystal alignment film for a horizontally oriented liquid crystal display element such as a TN mode. Yes, and it 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 alignment agent of the present invention is particularly suitable for a liquid crystal alignment film for a vertically oriented liquid crystal display element such as a VA method or a PSA mode. Further, the liquid crystal alignment film for the vertically oriented liquid crystal display element such as the VA method or the PSA mode may be obtained by using an alignment treatment including a photoalignment treatment. The light, the light source, and the irradiation amount of the light to be irradiated in the photo-alignment treatment are as described above.
The liquid crystal alignment film obtained from the liquid crystal alignment agent containing the polyimide varnish of the present invention is 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 transmission scattering type liquid crystal dimming element. It can also be used as a liquid crystal alignment film for liquid crystal display, or other applications such as a protective film for a color filter, a gate insulating film for a flexible display, and a substrate material.

The liquid crystal display element using the liquid crystal alignment agent of the present invention can be applied to various devices. For example, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays and the like.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples. The abbreviations and measurement methods of the compounds used below are as follows.
(Tetracarboxylic dianhydride)
BODA: Bicyclo [3.3.0] octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride PMDA: pyromellitic dianhydride TCA: 2,3,5-tricarboxycyclopentyl acetate dianhydride TDA: 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalensuccinic dianhydride 13DM-CBDA: 1,3-CBDA Dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

(Diamine)
PDA: p-phenylenediamine DBA: 3,5-diaminobenzoic acid 3AMPDA: 3,5-diamino-N- (pyridin-3-ylmethyl) benzamide

Vertically oriented diamine represented by the following formula DA-1

Diamine represented by the following formulas DA-2 to 9

(Boc represents a tert-butoxycarbonyl group.)
(Methyl compound)
Methacrylic compounds represented by the following formulas MA-1 to 3

(Radical polymerization initiator)
AIBN: Azobisisobutyronitrile

<Solvent>
NMP: N-methyl-2-pyrrolidone, BCS: Butyl cellosolve <amine compound (B)>
3AMP: 3-picorylamine, Me-3AMP: N-methyl-3-picorylamine MBA: N-methylbenzylamine, DMBA: N, N-dimethylbenzylamine

<Molecular weight measurement>
Equipment: Room temperature gel permeation chromatography (GPC) equipment (SSC-7200) manufactured by Senshu Kagaku Co., Ltd.,
Column: Shodex column (KD-803, KD-805)
Column temperature: 50 ° C
Eluent: N, N-dimethylformamide (as an additive, lithium bromide monohydrate (LiBr · H ₂ O) is 30 mmol / L, phosphoric acid / anhydrous crystal (o-phosphate) is 30 mmol / L, tetrahydrofuran (THF) is 10 mL / L), flow velocity: 1.0 ml / min Standard sample for preparing calibration lines: TSK standard polyethylene oxide manufactured by Toso Co., Ltd. (molecular weight: about 900,000, 150,000, 100,000, 30,000) , And polyethylene glycol manufactured by Polymer Laboratory Co., Ltd. (molecular weight: about 12,000, 4,000, 1,000).

<Measurement of imidization rate>
20 mg of polyimide powder is placed in an NMR sample tube (NMR sampling tube standard φ5 manufactured by Kusano Kagaku Co., Ltd. _{), 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d 6} , 0.05% TMS mixture) is added, and ultrasonic waves are applied. It was completely dissolved over. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNW-ECA500) manufactured by JEOL Datum. The imidization rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of the amic acid appearing in the vicinity of 9.5 to 10.0 ppm. It was calculated by the following formula using the integrated value.
In the following formula, x indicates the integrated proton peak value derived from the NH group of the amic acid, y indicates the integrated peak value of the reference proton, and α indicates the amic acid in the case of polyamic acid (imidization rate is 0%). The number ratio of the reference protons to one proton of the NH group of is shown.
Imidization rate (%) = (1-α · x / y) × 100

<Viscosity measurement>
Regarding the viscosity of the liquid crystal alignment agent, an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) was used, a sample volume of 1.1 mL was used, and a cone rotor TE-1 (1 ° 34', R24) was used, and the temperature was 25 ° C. Measured at.

(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) in NMP (357 g). After dissolving at 60 ° C. for 3 hours, PMDA (13.1 g, 60.0 mmol) was added, followed by CBDA (34.1 g, 174 mmol) and NMP (137 g), and the mixture was reacted at 25 ° C. for 10 hours. A polyamic acid solution was obtained.
NMP was added to this polyamic acid solution (500 g) to dilute it to 6.5% by mass, acetic anhydride (111 g) and pyridine (34.5 g) were added as imidization catalysts, and the mixture was reacted at 60 ° C. for 3 hours. This reaction solution was put into methanol (7000 mL), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a polyimide powder (A). The imidization ratio of this polyimide was 80%, the number average molecular weight was 12,000, and the weight average molecular weight was 24,000.

(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), DA- 6 (16.5 g, 50.0 mmol) was mixed in NMP (455 g) and reacted at 60 ° C. for 15 hours to obtain a polyamic acid solution having a resin solid content concentration of 20% by mass.
NMP is added to this polyamic acid solution (100 g) to dilute it to 6.5% by mass, acetic anhydride (17.9 g) and pyridine (5.55 g) are added as imidization catalysts, and the mixture is reacted at 100 ° C. for 3 hours. rice field. This reaction solution was put into methanol (1160 ml), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder (B). The imidization ratio of this polyimide was 72%, the number average molecular weight was 13,300, and the weight average molecular weight was 40,500.

(Synthesis Example 3)
TDA (30.0 g, 100 mmol), PDA (9.73 g, 90 mmol) and DA-3 (3.77 g, 10.0 mmol) are dissolved in NMP (247 g) and reacted at 40 ° C. for 3 hours to form a polyamic acid solution. Got
NMP was added to this polyamic acid solution (50 g) to dilute it to 5% by mass, acetic anhydride (17.6 g) and pyridine (8.20 g) were added as imidization catalysts, and the mixture was reacted at 40 ° C. for 3 hours. This reaction solution was put into methanol (600 ml), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain a polyimide powder (C). The imidization ratio of this polyimide was 85%, the number average molecular weight was 13400, and the weight average molecular weight was 27,000.

(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), DA-9 (5.46 g, 16.0 mmol) was dissolved in NMP (277 g) and reacted at 50 ° C. for 15 hours to obtain a polyamic acid solution.
NMP was added to this polyamic acid solution (100 g) to dilute it to 9% by mass, acetic anhydride (7.60 g) and pyridine (0.98 g) were added as imidization catalysts, and the mixture was reacted at 55 ° C. for 3 hours. This reaction solution was put into methanol (530 ml), and the obtained precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder (D). The imidization ratio of this polyimide was 66%, the number average molecular weight was 14300, and the weight average molecular weight was 35800.

(Synthesis Example 5)
Four-necked flask containing 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). In addition, each monomer component was completely dissolved. This solution was degassed with a diaphragm pump, AIBN (0.550 g, 3.33 mmol) was added as a polymerization initiator, and degassing was performed again. Then, the reaction was carried out at 60 ° C. for 13 hours to obtain a methacrylic polymer solution (E). The number average molecular weight of this polymer was 15800 and the weight average molecular weight was 68200.

(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% by mass NMP solution, 6.00 g) was added as the amine compound (B), and further, NMP (4.00 g) and BCS (40.0 g) were added, and 3 at room temperature. The liquid crystal aligning agent (A1) was obtained by stirring for a time.

(Examples 2 and 3 and Comparative Examples 1 and 2)
Liquid crystal alignment agents (A2) to (A5) were prepared by carrying out the same procedure except that the type of the added amine compound (B) was changed in Example 1. Table 1 below shows each of the obtained liquid crystal alignment agents and the amine compound (B) used therein.
In Comparative Example 2, the amine compound (B) was not added.

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

<Evaluation of whitening characteristics>
0.1 mL of the liquid crystal alignment agent obtained in Examples 1 to 3 and Comparative Example 1 or 2 was added dropwise onto the chromium substrate, and the mixture was allowed to stand in an environment of a temperature of 23 ° C. and a humidity of 70%. The edge and the central part of the droplet were observed with an optical microscope, and the time until the precipitate was formed was measured.
In this evaluation, the phenomenon in which the droplets become white and turbid due to the precipitation or aggregation of the dissolved polyimide is defined as the whitening phenomenon. The state in which the droplets were not whitened at all was evaluated as “◯”, the state in which only the edges of the droplets were whitened was evaluated as “Δ”, and the state in which the entire surface of the droplets was whitened was evaluated as “x”.
Table 4 shows the evaluation results of the whitening characteristics of the liquid crystal alignment agent 3 days after the storage stability test.

From the results in Tables 2 and 3, the decrease in viscosity and molecular weight can be significantly suppressed in Examples 1 to 3 as compared with the change in viscosity and molecular weight in Comparative Example 1, and the storage stability of the polyimide varnish is improved. I understand.
Further, from the results of the whitening test in Table 4, it can be seen that the whitening characteristics of Examples 1 to 3 are significantly improved as compared with Comparative Example 2.
Further, from the results in Table 4, it can be seen that the whitening characteristics of Examples 1 to 3 are less likely to deteriorate as compared with Comparative Example 1. This is because the aliphatic amine of 3AMP is a primary amine, which makes it easier to perform a nucleophilic attack on the main chain of polyimide, whereas the secondary and tertiary amines are mainly polyimide due to the influence of steric hindrance. It is considered that this is because the nucleophilicity to the chain is suppressed.

(Examples 4 to 8, Comparative Examples 3 to 12, Synthesis Examples 6 to 8)
In Example 1, the liquid crystal alignment agents (B1) to (B2), (C1) to (C3) were carried out in the same manner except that the polyimide powder, the amine compound and the organic solvent were changed as shown in Table 5 below. And (D1) to (D3) were prepared.
Further, 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 at room temperature. The mixture was stirred for 3 hours to obtain a liquid crystal aligning agent (E1) (Synthesis Example 6). Further, in Synthesis Example 6, liquid crystal alignment agents (E2) to (E3) were prepared by carrying out the same procedure except that the amine compound was changed as shown in Table 5 below (Synthesis Examples 7 and 8).
Table 5 shows the combinations of each liquid crystal alignment agent and the additives used therein.

Subsequently, the liquid crystal alignment agents (B1) to (B3), (E1) to (E3) obtained so far were blended with the liquid crystal alignment agents (A2), (A4), and (A5).
Table 6 shows the combination of the blended liquid crystal alignment agent and the combination of the additives contained in the liquid crystal alignment agent.

The liquid crystal alignment agent obtained above was subjected to a storage stability test and an evaluation of whitening characteristics in the same manner as described above. The results are shown in Tables 7 to 10 below.

<Storage stability test>

<Evaluation of whitening characteristics>
Table 9 shows the evaluation results performed on the day of preparation of the liquid crystal alignment agent, and Tables 9 and 10 show the evaluation results 3 days after the storage stability test described above.

From the results in Tables 7 and 8, it can be seen that in Examples 5 to 8, the decrease in viscosity and molecular weight can be significantly suppressed, and the storage stability is improved.
Further, from the results of the whitening test in Tables 9 and 10, it can be seen that the whitening characteristics of Examples 5 to 8 are significantly improved as compared with Comparative Examples 5 to 12.

The polyimide varnish of the present invention is widely used as a film-like protective material and an insulating material in the electric and electronic fields, including a liquid crystal aligning agent for forming a liquid crystal alignment film in a liquid crystal display element and an insulating film for semiconductors. Widely used in the field.

The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2020-30729 filed on February 26, 2020 are cited here and incorporated as disclosure of the specification of the present invention. Is.

Claims (17)

1. A polyimide varnish containing the following components (A) and (B).
   Component (A): Polyimide (A) which is an imidized product of a polyimide precursor.
   Component (B): The molecule has any one of a secondary amino group or a tertiary amino group and a cyclic group of any one of a nitrogen-containing aromatic heterocycle or an aromatic hydrocarbon group. The amine compound (B) in which the amino group is bonded to an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group.
2. The polyimide varnish according to claim 1, wherein the amine compound (B) is represented by the following formula (1).
   

   

   (R ₁ and R ₂ represent a hydrogen atom or an alkyl group _{having 1 to 5 carbon atoms, and at least one of R 1} and R ₂ represents an alkyl group having 1 to 5 carbon atoms. Ar represents a nitrogen-containing aromatic complex. It represents a ring or aromatic hydrocarbon group. X represents a divalent organic group containing an acyclic aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group. R ₁ and R ₂ are bonded. N is bonded to the acyclic aliphatic hydrocarbon group or the non-aromatic cyclic hydrocarbon group.)
3. In the formula (1), the amine compound (B) is * 1-X _1- X _2- * 2 (where X ₁ is an acyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms or a non-cyclic aliphatic hydrocarbon group. Represents a divalent organic group containing an aromatic cyclic hydrocarbon group. X ₂ is a single bond, -O-, -NH-, -S-, -SO _2- or divalent with 1 to 19 carbon atoms. It represents an organic group. _{The total number of carbon atoms contained in X 1} and X ₂ is 1 to 20. * 1 is a bond that binds to N in formula (1), and * 2 is a bond in formula (1). The polyimide varnish according to claim 2, which is a compound represented by (a binder that binds to Ar).
4. The polyimide varnish according to claim 3, wherein in -X _1- X _2- , X ₁ is a divalent acyclic aliphatic hydrocarbon group having 1 to 10 carbon atoms or a non-aromatic cyclic hydrocarbon group. ..
5. The invention according to any one of claims 1 to 4, wherein the amine compound (B) is one or more of the compounds represented by any of the following formulas (b-1) to (b-14). Polyimide varnish.
   

   
6. Any of claims 1 to 5, wherein the polyimide precursor of the polyimide (A) is obtained by using a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (3) or a derivative thereof. The polyimide varnish according to item 1.
   

   

   (X represents a structure selected from the group consisting of the following (x-1) to (x-13).)
   

   

   (R ¹ to R ⁴ are independently hydrogen atom, methyl group, ethyl group, propyl group, chlorine atom, fluorine atom, monovalent organic group having 1 to 6 carbon atoms containing fluorine atom, or phenyl. Representing a group. R ⁵ and R ⁶ independently represent a hydrogen atom or a methyl group. J and k are independently integers of 0 or 1, respectively, and A _{1 and A 2 are respectively.} Independently, it represents a single bond, -O-, -CO-, -COO-, a phenylene, a sulfonyl group, or an amide group. * 1 is a bond that binds to one acid anhydride group, and * 2 is a bond. .2 one a ₂ is a bond that binds to the other acid anhydride groups may be be the same or different.)
7. In the tetracarboxylic dianhydride represented by the formula (3) or a derivative thereof, X is a tetra having the formulas (x-1) to (x-7) and (x-11) to (x-13). The polyimide varnish according to claim 6, which is a carboxylic acid dianhydride or a derivative thereof.
8. The invention according to any one of claims 1 to 7, wherein the polyimide precursor of the polyimide (A) is obtained by using a diamine (a) having a structure represented by the following formulas (S1) to (S3). Polyimide varnish.
   

   

   (X ¹ and X ² are independent, 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- . Of these, a1 is an integer of 1 to 15, and A ₁ is. , Oxygen atom or -COO-, m ₁ is 1-2. G ¹ and G ² are independently divalent aromatic groups having 6 to 12 carbon atoms or 3 to 8 carbon atoms. Represents a divalent cyclic group of a divalent alicyclic group. Any hydrogen atom on the cyclic group may be substituted. M and n are independently integers of 0 to 3, respectively. 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, and any hydrogen atom forming ^{R 1.} May be substituted with a fluorine atom. If there are two or more ^{X 1} , X ² , G ¹ , G ² , a 1, and A ₁ ^{, two or more X 1} , X ² , G ¹ , G ^2. , a1, and a ₁ may be different even in the same independently.)
   

   

   (X ³ represents a single bond, _{-CONH-, -NHCO-, -CON (CH 3} )-, _{-NH-, -O-, -CH 2} O-, -COO- or -OCO- R ² Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon ^{atoms, and any hydrogen atom forming R 2} may be substituted with a fluorine atom.)
   

   

   (X ⁴ represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -OCH _2- ^{, -COO- or -OCO-. R 3} represents a structure having a steroid skeleton.)
9. The polyimide varnish according to claim 8, wherein the diamine (a) is at least one diamine selected from the group consisting of the following formulas (V-1) to (V-13).
   

   

   

   (In the above formula, X ^v1 to X ^v4 and X ^p1 to X ^p8 are independent _{of-(CH 2} ) _a- (a is an integer of 1 to 15), -CONH-, and -NHCO-. , -CON (CH ₃ )-, _{-NH-, -O-, -CH 2} O-, -CH ₂ OCO-, -COO-, or -OCO-, and X ^v5 is -O-, -CH ₂ It _{indicates O-, -CH 2} OCO-, -COO-, or -OCO-, and X ^V6 to X ^V7 and X ^s1 to X ^s4 are independently -O-, -CH ₂ O-, and -OCH _2. -, -COO- or -OCO-. X _a to X _f are independently single-bonded, -O-, _{-NH-, -O- (CH 2} ) _m- O-, -C ( CH ₃ ) _2- , -CO-, -COO-, -CONH-,-(CH ₂ ) _m- , -SO _2- , -OC (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 -, - It indicates CONH- (CH ₂ ) _m- , -CONH- (CH ₂ ) _m- NHCO-, or -COO- (CH ₂ ) _m- OCO-, and R ^v1 to R ^v4 and R ^1a to R ^1h are independent of each other. 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 is shown. M represents an integer of 1 to 8).
10. The polyimide varnish according to any one of claims 1 to 9, wherein the polyimide (A) has a structure in which 20 to 90% of all repeating units of the polyimide precursor are ring-closed.
11. The polyimide according to any one of claims 1 to 10, wherein the amine compound (B) is contained in a ratio of 0.1 to 50 parts by mass with respect to 100 parts by mass of the polyimide (A). varnish.
12. A liquid crystal alignment agent obtained from the polyimide varnish according to any one of claims 1 to 11.
13. At least one other selected from the group consisting of a polyimide precursor, a polysiloxane, a polyester, a polyamide, a polyurea, a polyorganosiloxane, a cellulose derivative, a polyacetal, and a polymer of a monomer having a polymerizable unsaturated bond. The liquid crystal aligning agent according to claim 12, further containing the polymer of the above.
14. The polymer of the monomer having a polymerizable unsaturated bond is a (meth) acrylic compound, a (meth) acrylic acid amide compound, an aromatic vinyl compound, a conjugated diene compound, a maleimide group-containing compound, α-methylene-γ-. The liquid crystal alignment agent according to claim 12 or 13, which is obtained by using at least one compound selected from the group consisting of a butyrolactone compound, a vinyl compound other than an aromatic vinyl compound, and a compound containing a maleic anhydride structure.
15. The polymer of the monomer having a polymerizable unsaturated bond has a monomer represented by the following formula (S-mA), a monomer having a polymerizable unsaturated bond with a carboxy group, and a polymerizable unsaturated bond with an epoxy skeleton. The liquid crystal aligning agent according to any one of claims 12 to 14, which is obtained by using at least one monomer selected from the group consisting of monomers.
    

    

    (P represents 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 of 1 to 15, A ₁ represents an oxygen atom or -COO-, and m ₁ is 1 to 1 to If .m ₁ is 2 is the second integer, a plurality of a1 and _{a 1} are each independently have the above definitions), or a group. - represents "-L-OCO-CR '= CR "'. However, when P is a (meth) acryloyloxy group, a vinyloxy group (CH ₂ = CH—O—), or a maleimide group, X represents a single bond or a linking group that is bonded to P via a carbon atom.
    J represents a monovalent organic group having at least one group selected from the group consisting of an alicyclic hydrocarbon group having 4 to 40 carbon atoms and an aromatic hydrocarbon group having 6 to 40 carbon atoms. At least one of the hydrogen atoms contained in the alicyclic hydrocarbon group and the aromatic hydrocarbon group is a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, and 3 carbon atoms. The carbon-carbon bond contained in an alkoxy group of ~ 10 and an alkenyl group having 3 to 10 carbon atoms, and any methylene group of the halogen atom-containing alkyl group, halogen atom-containing alkoxy group, alkyl group, alkoxy group, and alkenyl group. It is substituted with a substituent selected from the group consisting of hetero-atom-containing groups interrupted by oxygen atoms.
    In the group "-L-OCO-CR'= CR"-", L is a single bond or-(B _1- (CH ₂ ) _b1 ) _m' -(b1 is an integer of 1 to 15. B ₁ represents a single _{bond, -CONH -, - NHCO -,} - CON (CH 3) -, - NH -, - O -, - .m representing the COO- or -OCO- ^'is an integer of 1 to 2. If m ^'is 2, a plurality of b1 and B ₁ each independently have the above definitions, at least one of B ₁ represents represents a 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.)
16. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to any one of claims 12 to 15.
17. A liquid crystal display element including the liquid crystal alignment film according to claim 16.