CN110869842B

CN110869842B - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element using same

Info

Publication number: CN110869842B
Application number: CN201880046891.0A
Authority: CN
Inventors: 军司里枝; 大田政太郎; 藤枝司
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2017-07-14
Filing date: 2018-07-13
Publication date: 2022-06-03
Anticipated expiration: 2038-07-13
Also published as: KR102572922B1; CN110869842A; WO2019013339A1; TWI758513B; JPWO2019013339A1; KR20200027967A; JP7093059B2; TW201920362A

Abstract

A polymer containing a polyimide precursor obtained from a diamine component containing a diamine having a structure represented by the following formula (1) and a diamine having a predetermined side chain structure and/or a polyimide which is an imide compound of the polyimide precursor. (in the formula (1), R₁Represents hydrogen, alkyl or fluoroalkyl having 1 to 5 carbon atoms, t-butoxycarbonyl, or a 1-valent organic group. Denotes the site of bonding to other groups. Any hydrogen atom forming a phenyl ring is optionally substituted with a 1-valent organic group. )

Description

Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element using same

Technical Field

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element using the same. In particular, the present invention relates to a liquid crystal aligning agent and a liquid crystal alignment film suitable for a VA liquid crystal display element in which liquid crystal molecules aligned vertically to a substrate are responded to by an electric field, and to the liquid crystal display element using the same.

Background

Liquid crystal display elements are widely used as display portions of computers, mobile phones, smart phones, televisions, and the like. The liquid crystal display element includes, for example, a liquid crystal layer interposed between an element substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls alignment of liquid crystal molecules of the liquid crystal layer, a Thin Film Transistor (TFT) that switches an electric signal supplied to the pixel electrode, and the like.

As one of driving methods of such a liquid crystal display element, there is a method (also referred to as a Vertical Alignment (VA) method) in which liquid crystal molecules aligned vertically to a substrate are caused to respond to an electric field. Among liquid crystal display elements of the vertical alignment type, there is known a technique (psa (polymer suspended alignment) type element) in which a photopolymerizable compound is added to a liquid crystal composition in advance, and ultraviolet rays are irradiated while applying a voltage to a liquid crystal cell using a vertical alignment film such as a polyimide-based film, thereby increasing the response speed of the liquid crystal (for example, see patent document 1 and non-patent document 1.).

On the other hand, in such a liquid crystal display element, when static electricity is accumulated in the liquid crystal cell and electric charges are accumulated in the liquid crystal cell due to application of positive and negative asymmetric voltages generated by driving, the accumulated electric charges affect display in the form of disturbance of liquid crystal alignment or afterimage, and the display quality of the liquid crystal element is significantly degraded.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open publication No. 2003-307720

Non-patent document

Non-patent document 1K. Hanaoka, SID 04DIGEST, P1200-1202

Disclosure of Invention

Problems to be solved by the invention

The invention provides a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film with excellent voltage holding ratio, fast relaxation of accumulated charges and excellent afterimage characteristics, a liquid crystal alignment film and a liquid crystal display element using the liquid crystal alignment film.

Means for solving the problems

The present inventors have conducted extensive studies and as a result, have found that the above-mentioned problems can be solved by preparing a liquid crystal aligning agent containing a diamine having a specific structure in a polymer, and have completed the present invention. The present invention has been completed based on the above findings, and the gist thereof is as follows.

The invention for solving the above problems is a liquid crystal aligning agent containing a polyimide precursor obtained from a diamine component containing a diamine having a structure represented by the following formula (1) and at least 1 kind of diamine having a side chain structure selected from the group consisting of the following formulae [ S1] to [ S3] and a tetracarboxylic acid component (including a tetracarboxylic acid derivative component) and/or a polymer of polyimide which is an imide compound of the polyimide precursor.

(in the formula (1), R₁Represents hydrogen, alkyl or fluoroalkyl having 1 to 5 carbon atoms, t-butoxycarbonyl, or a 1-valent organic group. Denotes the site of bonding to other groups. Any hydrogen atom forming a phenyl ring is optionally substituted with a 1-valent organic group. )

(formula [ S1]]In, X¹And X²Each independently represents 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-A₁)_m1-. Wherein a1 are each independently an integer of 1-15, A₁Each independently represents an oxygen atom or-COO-, m₁Is 1 to 2. G¹And G²Each independently represents a 2-valent cyclic group selected from a 2-valent aromatic group having 6 to 12 carbon atoms or a 2-valent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group is optionally substituted by at least 1 selected from the group consisting of alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms, fluoroalkyl group having 1 to 3 carbon atoms, fluoroalkoxy group having 1 to 3 carbon atoms, and fluorine atom. m and n are respectively and independently integers of 0-3, and the sum of m and n is 1-4. R¹Represents 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 atomsGroup, form R¹Optionally substituted with fluorine. )

-X³-R² [S2]

(formula [ S2]]In, X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-. R is²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine. )

-X⁴-R³ [s3]

(formula [ S3]]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-. R³Represents a structure having a steroid skeleton. )

Here, the diamine having the structure of the formula (1) preferably has the structure of the formula (1-1).

(in the formula (1-1), R₁The same as in the case of the aforementioned formula (1). Denotes the site of bonding to other groups. Any hydrogen atom forming a phenyl ring is optionally substituted with a 1-valent organic group. )

The diamine having the structure of the formula (1) preferably has the structure of the formula (1-4).

(in the formula (1-4), R₁The same as in the case of the aforementioned formula (1). 2 of Q₂Each independently represents a single bond or a 2-valent organic group. Any hydrogen atom forming a phenyl ring is optionally substituted with a 1-valent organic group. )

The diamine component preferably contains a diamine having a side chain structure represented by the formula [ S1 ].

The side chain structure represented by the formula [ S1] is preferably at least 1 selected from the group consisting of the following formulas [ S1-x1] to [ S1-x7 ].

(formula [ S1-x 1)]～[S1-x7]In, R¹Represents an alkyl group having 1 to 20 carbon atoms. X^pIs represented by- (CH)₂)_a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-. A. the₁Represents an oxygen atom or-COO- (-CH-) -connecting bond₂)_a2Bonding). A. the₂Represents an oxygen atom or-COO- (wherein, a bond having "-" is bonded to the atom and (CH))₂)_a2Bonding). a3 is an integer of 0 or 1, and a1 and a2 are each independently an integer of 2-10. Cy represents a1, 4-cyclohexylene group or a1, 4-phenylene group. )

Further, the formula [ S2]]Among the diamines having a side chain structure shown, X is preferred³is-CONH-, -NHCO-, -O-, -CH₂O-, -COO-or-OCO-, R²Is C3-20 alkyl or C2-20 alkoxyalkyl.

The side chain structure represented by the formula [ S3] preferably has a structure represented by the following formula [ S3-x ].

(in the formula [ S3-X ], X represents the formula [ X1] or the formula [ X2 ]. Col represents at least 1 selected from the group consisting of the formulae [ Col1] to [ Col3 ]. G represents the formulae [ G1] to [ G4 ]. in these formulae, the symbol represents a bonding position.)

The diamine component having the specific side chain structure preferably contains at least 1 kind selected from diamines represented by the following formulae [1] and [2 ].

(formula [1]]Wherein X represents a single bond, -O-, -C (CH)₃)₂-、-NH-、-CO-、-(CH₂)_m-、-SO₂Or from themAny combination of (a) or (b) to form a 2-valent organic group. m is an integer of 1 to 8. 2Y' S are independently selected from the group consisting of the formula [ S1]]～[S3]At least 1 of the side chain structures shown. )

Another aspect of the present invention to solve the above problems is a liquid crystal alignment film formed using any of the liquid crystal aligning agents described above.

Another aspect of the present invention for solving the above problems is a liquid crystal display element including a liquid crystal alignment film obtained from the above liquid crystal alignment film.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film having excellent voltage holding ratio, rapid relaxation of accumulated charge, and excellent image sticking characteristics can be provided, and a liquid crystal display element having excellent display characteristics can be provided. That is, the liquid crystal alignment film and the liquid crystal display element according to the present invention can meet the recent expectations for the characteristics of the liquid crystal alignment film and the liquid crystal display element with the increase in performance.

Detailed Description

The liquid crystal aligning agent contains a polyimide precursor obtained from a diamine component containing a diamine having a structure represented by the following formula (1) and at least 1 diamine having a side chain structure selected from the group consisting of the following formulae [ S1] to [ S3] and a tetracarboxylic acid component and/or a polymer of polyimide which is an imide compound of the polyimide precursor.

Hereinafter, the diamine having the structure of the formula (1) may be referred to as "diamine having a specific structure" or "specific diamine". In addition, at least 1 kind of diamine having a side chain structure selected from the group consisting of the formulas [ S1] to [ S3] may be referred to as "diamine having a specific side chain structure". In addition, a polymer containing the specific diamine of the present invention and a diamine having a specific side chain structure is sometimes referred to as a "specific polymer".

< specific diamine >

The specific diamine has a structure represented by the following formula (1).

In the above formula (1), R₁Represents hydrogen, alkyl or fluoroalkyl having 1 to 5 carbon atoms, t-butoxycarbonyl, or a 1-valent organic group. Denotes the site of bonding to other groups. Any hydrogen atom forming a phenyl ring is optionally substituted with a 1-valent organic group. The 1-valent organic group herein includes an alkyl group, alkenyl group, alkoxy group, fluoroalkyl group, fluoroalkenyl group, or fluoroalkoxy group having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. Wherein R is₁Preferably a hydrogen atom or a methyl group.

In the above formula (1), the bonding position of the benzene ring to the pyrrole ring is preferably a carbon atom adjacent to the nitrogen atom on the pyrrole ring as shown in the following formula (1-1) from the viewpoint of charge transfer.

Examples of the specific diamine include those represented by the following formula (1-2), particularly those represented by the following formula (1-3), and more particularly those represented by the following formula (1-4).

In the above formulae (1-2) to (1-4), R₁The same as in the case of formula (1). Q₁And Q₂Each independently represents a single bond or a 2-valent organic group. I.e. Q₁And Q₂May be of different construction from one another. In addition, in the formula (1-4), 2Q₂May be of different construction from one another. Further, any hydrogen atom forming a benzene ring may be substituted with a 1-valent organic group as in the case of formula (1).

Preferable examples of the specific diamine include diamines represented by the following formula (2), and more preferably diamines represented by the following formula (2-1).

In the above formulae (2) and (2-1), R₁The same as in the case of formula (1). 2R₂Each independently represents a single bond or a structure represented by the following formula (3). It is to be noted that, as in the case of formula (1), any hydrogen atom forming a benzene ring is optionally substituted with a 1-valent organic group.

In the formula (3), R₃Represents a group selected from the group consisting of a single bond, -O-, -COO-, -OCO-, - (CH)₂)_p-、-O(CH₂)_mO-、-CONH-、-NHCO-、-CON(CH₃) -and-N (CH)₃)CO-、-NR₁-a 2-valent organic group of the group. Wherein p and m are each independently an integer of 1 to 14, R₁The same as in the case of formula (1). Wherein, starting from the point of neutralizing the accumulated charge, R₃Preferably a single bond, -O-, -COO-, -OCO-, -CONH-, -NHCO-or-N (CH)₃) -. In addition, 1 represents a site bonded to the benzene ring in formula (2). And 2 represents a site bonded to the amino group in formula (2). In the formula (2) and the formula (2-1), n is an integer of 1 to 3, preferably 1 or 2.

Specific examples of the above formula (2) include the following formulae (2-1-1) to (2-1-16), but are not limited thereto. Among them, preferred are the formula (2-1-1), the formula (2-1-2), the formula (2-1-3), the formula (2-1-5), the formula (2-1-8), the formula (2-1-9), the formula (2-1-10), the formula (2-1-11), the formula (2-1-12), the formula (2-1-13), the formula (2-1-14), the formula (2-1-15) or the formula (2-1-16), particularly preferred are the formula (2-1-1), the formula (2-1-2), the formula (2-1-3), the formula (2-1-11) or the formula (2-1-12), the formula (2-1-13), and mixtures thereof, Formula (2-1-14), formula (2-1-15) or formula (2-1-16). In the following formulae (2-1-6) and (2-1-7), n is an integer of 1 to 14.

< Synthesis method of specific diamine >

The method for synthesizing the specific diamine is not particularly limited. For example, the following methods may be mentioned: a dinitro compound represented by the following formula (4) is used to convert the nitro group thereof into an amino group by a reduction reaction.

In the formula (4), R₁The same as in the case of formula (1).

The catalyst used in the reduction reaction is preferably an activated carbon-supported metal which is commercially available, and examples thereof include palladium-activated carbon, platinum-activated carbon, rhodium-activated carbon, and the like. Further, palladium hydroxide, platinum oxide, raney nickel, or the like may be used, but it is not necessarily an activated carbon-supported metal catalyst. Generally, widely used palladium-activated carbon is preferable because good results can be easily obtained.

In order to more efficiently perform the reduction reaction, the reaction may be carried out in the presence of activated carbon. In this case, the amount of the activated carbon to be used is not particularly limited, but is preferably 1 to 30% by mass, more preferably 10 to 20% by mass, based on the dinitro compound of the formula (4). For the same reason, the reaction may be carried out under pressure. In this case, the reduction of the benzene ring and the pyrrole ring is prevented by a pressure range of atmospheric pressure to 20 atm. The reaction is preferably carried out in the range of atmospheric pressure to 10 atm.

The solvent used for the synthesis of the specific diamine is not limited as long as it does not react with each raw material. For example, it is possible to use: aprotic polar organic solvents (dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methyl-2-pyrrolidone, and the like); ethers (diethyl ether, diisopropyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane, etc.); aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (e.g., benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, and tetralin); halogen-based hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.) and the like. These solvents may be used in 1 kind, or in 2 or more kinds. Further, the solvent may be dried by using a suitable dehydrating agent or drying agent and used as a nonaqueous solvent.

The amount of the solvent used (reaction concentration) is not particularly limited, and is 0.1 to 100 times by mass relative to the dinitro compound of the formula (4). Preferably 0.5 to 30 times by mass, and more preferably 1 to 10 times by mass. The reaction temperature is not particularly limited, and is in the range of from-100 ℃ to the boiling point of the solvent used, preferably from-50 ℃ to 150 ℃. The reaction time is usually 0.05 to 350 hours, preferably 0.5 to 100 hours.

[ production method of dinitro Compound of formula (4) ]

The method for synthesizing the dinitro compound of the formula (4) is not particularly limited, and examples thereof include a method of synthesizing a compound represented by the following formula (5) (dinitro base) and introducing a protecting group R into an NH group of the dinitro base₄The method of (1).

Introduction of R₄In this case, any compound may be used as long as it can react with the NH site of the pyrrole ring of formula (5). Examples thereof include acid halides, acid anhydrides, isocyanates, epoxides, oxetanes, haloaromatics, and haloalkanes. In addition, alcohols in which the hydroxyl group of the alcohol is substituted with a leaving group such as OMs (methylsulfonyl), OTf (trifluoromethylsulfonyl), and OTs (tosyl) may be used.

By reaction with acyl halides to introduce R₄In the case of (3), it is preferably carried out in the presence of a base. Examples of the acid halide include acetyl chloride, propionyl chloride, methyl chloroformate, ethyl chloroformate, n-propyl chloroformate, isopropyl chloroformate, n-butyl chloroformate, isobutyl chloroformate, tert-butyl chloroformate, benzyl chloroformate, and 9-fluorene chloroformate. The base is not particularly limited as long as it can be synthesizedExamples of the base include inorganic bases such as potassium carbonate, sodium carbonate, cesium carbonate, sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, and sodium hydride, and organic bases such as pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and tributylamine. The reaction solvent and the reaction temperature are the same as those in the reduction reaction in the synthesis of the dinitro compound of formula (4).

By reaction with anhydrides to introduce R₄In the case of (2), examples of the acid anhydride include acetic anhydride, propionic anhydride, dimethyl dicarbonate, diethyl dicarbonate, di-t-butyl dicarbonate, and dibenzyl dicarbonate. In order to accelerate the reaction, pyridine, collidine, N-dimethyl-4-aminopyridine, etc. may be used as a catalyst. The amount of the catalyst is 0.0001 to 1mol based on the compound of the formula (5). The reaction solvent and the reaction temperature are the same as in the above acid halide.

By reaction with isocyanates to introduce R₄In the case of (2), examples of the isocyanate include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and phenyl isocyanate. The reaction solvent and the reaction temperature are the same as in the above acid halide.

By reaction with epoxy compounds or oxetane compounds to introduce R₄In the case of (2), examples of the epoxy compounds and oxetanes include ethylene oxide, propylene oxide, 1, 2-butylene oxide, and oxetane. The reaction solvent and the reaction temperature are the same as in the above acid halide.

R is introduced by reacting an alcohol having a hydroxyl group of the alcohol substituted with a leaving group such as OMs, OTf, OTs or the like₄In the case of (3), it is preferably carried out in the presence of a base. Examples of the alcohol include methanol, ethanol, and 1-propanol, and these alcohols are reacted with methanesulfonyl chloride, trifluoromethanesulfonyl chloride, and p-toluenesulfonyl chloride to obtain an alcohol substituted with a leaving group such as OMs, OTf, and OTs. Examples of the base, the reaction solvent and the reaction temperature are the same as those in the above-mentioned acid halide.

By reaction of alkyl halides to introduce R₄In the case of (2), it is preferably carried out in the presence of a base. As examples of the alkyl halide group, there may be mentioned,examples thereof include methyl iodide, ethyl iodide, n-propyl iodide, methyl bromide, ethyl bromide and n-propyl bromide. Examples of the base include, in addition to the above-mentioned bases, metal alkoxides such as potassium tert-butoxide and sodium tert-butoxide. The reaction solvent and the reaction temperature are the same as in the above acid halide.

[ production method of Compound of formula (5) ]

The method for synthesizing the compound of formula (5) is not particularly limited, and when the substitution position on the pyrrole ring of the compound of formula (5) is 2-position and 4-position, it can be obtained by, for example, reacting an α -haloketone having a nitro group with a ketone having a nitro group, preferably in the presence of a base, as shown in the following reaction formula 1. In the reaction formula 1, X represents Br, I or OTf.

As an example of the base used in the above reaction formula 1, the bases exemplified in the above acid halides can be used. The reaction solvent and the reaction temperature are the same as in the above acid halide. In order to accelerate the reaction rate in the above reaction formula 1, zinc chloride, sodium iodide, potassium iodide, tetrabutylammonium iodide, etc. may be used as an accelerator.

On the other hand, when the substitution on the pyrrole ring of the compound of formula (5) is other than the 2-position and the 4-position, it can be obtained by reaction formula 2 in which the corresponding halogenopyrrole and the organometallic reagent are subjected to a cross-coupling reaction preferably using a metal catalyst.

(in the reaction formula 2, X represents Br, I or OTf. M represents B (OH))₂Or 4,4,5, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl. )

The cross-coupling reaction (also referred to as "suzuki-miyaura reaction") of the above reaction formula 2 preferably uses a metal complex and a ligand as a catalyst, but the reaction proceeds even in the absence of a catalyst. Examples of the metal complex include palladium acetate, palladium chloride-acetonitrile complex, palladium-activated carbon, bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, bis (acetonitrile) dichloropalladium, bis (benzonitrile) dichloropalladium, CuCl, CuBr, CuI, CuCN and the like. Examples of the ligand include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1, 2-bis (diphenylphosphino) ethane, 1, 3-bis (diphenylphosphino) propane, 1, 4-bis (diphenylphosphino) butane, 1' -bis (diphenylphosphino) ferrocene, trimethyl phosphite, triethyl phosphite, triphenyl phosphite, tri-t-butylphosphine, and the like. The amount of the metal complex to be used may be 20 mol% or less, preferably 10 mol% or less, based on the substrate, so-called catalyst amount.

< diamine having a specific side chain Structure >

In the present embodiment, the diamine having a specific side chain structure is represented by, for example, the following formulas [1] and [2 ].

The above formula [2]Wherein X represents a single bond, -O-, -C (CH)₃)₂-、-NH-、-CO-、-NHCO-、-COO-、-(CH₂)_m-、-SO₂-or a 2-valent organic group formed from any combination thereof. Wherein X is preferably a single bond, -O-, -NH-, -O- (CH)₂)_m-O-. As "an arbitrary combination of these", there may be mentioned-O- (CH)₂)_m-O-、-O-C(CH₃)₂-、-CO-(CH₂)_m-、-NH-(CH₂)_m-、-SO₂-(CH₂)_m-、-CONH-(CH₂)_m-、-CONH-(CH₂)_m-NHCO-、-COO-(CH₂)_mOCO-, etc., but not limited thereto. m is an integer of 1 to 8.

In the formulae [1] and [2], Y is at least 1 type selected from side chain structures represented by the formulae [ S1] to [ S3] independently. Details of the side chain structures represented by the formulae [ S1] to [ S3] are described later.

In the formula [2], the position of Y relative to X may be either the meta position or the ortho position, and is preferably the ortho position. That is, the formula [2] is preferably the following formula [ 2' ].

In addition, the above formula [2]]Middle, 2 amino (-NH)₂) The position (c) may be any position on the benzene ring, and is preferably represented by the following formula [2]]-a1～[2]A position represented by a3, more preferably represented by the following formula [2]]-a 1. In the following formula, X is the same as the above formula [2]]The same is true in (1). The following formula [2]]-a1～[2]A3 is for the purpose of illustrating the position of 2 amino groups, the above formula [2] being omitted]The label of Y shown in (a).

Therefore, the formula [2] is preferably any structure selected from the group consisting of the following formulae [2] -a1-1 to [2] -a3-2, and more preferably a structure represented by the following formula [2] -a1-1, based on the formulae [ 2' ] and [2] -a1 to [1] -a 3. In the following formulae, X and Y are the same as in the formula [2 ].

These two side chain diamines represented by the above formula [2] may be used alone in 1 kind, or in combination of 2 or more kinds. Depending on the properties required for the liquid crystal alignment film and the liquid crystal display element, 1 type or 2 or more types may be selected and used singly or in combination, and when 2 or more types are used in combination, the ratio thereof may be appropriately adjusted.

In the above formulas [1] and [2], Y represents a specific side chain structure selected from the group represented by the following formulas [ S1] to [ S3 ]. The specific side chain structure will be described below in the order of the formulae [ S1] to [ S3 ].

Examples of the specific side chain structure include diamines having a specific side chain structure represented by the following formula [ S1 ].

The above formula [ S1]In, X¹And X²Each independently represents 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-A₁)_m1-. Wherein a1 are each independently an integer of 1-15, A₁Each independently represents an oxygen atom or-COO-, m₁Is 1 to 2.

Wherein X is X from the viewpoints of availability of raw materials and ease of synthesis¹And X²Each independently is preferably a single bond, - (CH)₂)_a- (a is an integer of 1 to 15), -O-, -CH₂O-or-COO-. More preferably, X is¹And X²Are each independently a single bond, - (CH)₂) a- (a is an integer of 1 to 10), -O-, -CH₂O-or-COO-.

In addition, the above formula [ S1]]In (G)¹And G²Each independently represents a 2-valent cyclic group selected from a 2-valent aromatic group having 6 to 12 carbon atoms or a 2-valent alicyclic group having 3 to 8 carbon atoms. The optional hydrogen atom in the cyclic group is optionally substituted by an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms or a fluorine atom. m and n are respectively and independently integers of 0-3, and the sum of m and n is 1-4.

In addition, the above formula [ S1]]In, R¹Represents 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 to form R¹Optionally substituted with fluorine. Examples of the 2-valent aromatic group having 6 to 12 carbon atoms include phenylene, biphenylene, and naphthyl groups. Examples of the 2-valent alicyclic group having 3 to 8 carbon atoms include cyclopropylene and cyclohexylene.

Therefore, preferred specific examples of the formula [ S1] include, but are not limited to, the following formulas [ S1-x1] to [ S1-x7 ].

The above formula [ S1-x1]～[S1-x7]In, R¹And the above formula [ S1]The same is true in (1). X^pIs represented by- (CH)₂)_a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON (CH)₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-. A. the₁Represents an oxygen atom or a bond of-COO-and (CH)₂)_a2Bonding). A. the₂Represents an oxygen atom or a bond of-COO- (with a:) with (CH)₂)_a2Bonding). a1 is an integer of 0 or 1, and a2 is an integer of 2-10. Cy, i.e., the group denoted by "Cy" in the cyclohexane ring, represents 1, 4-cyclohexylene or 1, 4-phenylene.

Examples of the specific side chain structure include a specific side chain structure represented by the following formula [ S2 ].

-X³-R² [S2]

The above formula [ S2]In, X³Represents a single bond, -CONH-, -NHCO-, -CON (CH)₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-. Wherein, from the viewpoint of liquid crystal alignment, X³preferably-CONH-, -NHCO-, -O-, -CH₂O-, -COO-or-OCO-. R is²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine. Wherein R is from the viewpoint of liquid crystal alignment²Preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms.

Further, as an example of the specific side chain structure, there is a specific side chain structure represented by the following formula [ S3 ].

-X⁴-R³ [S3]

The above formula [ S3]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-. R³Represents a structure having a steroid skeleton. The steroid skeleton herein has 3 6-membered rings and 1 5-membered ring bondedA skeleton represented by the following formula (st).

Examples of the formula [ S3] include, but are not limited to, the following formula [ S3-x ].

In the formula [ S3-X ], X represents the formula [ X1] or [ X2 ]. Further, Col represents at least 1 species selected from the group consisting of the above-described formulas [ Col1] to [ Col3], and G represents at least 1 species selected from the group consisting of the above-described formulas [ G1] to [ G4 ]. Denotes the site of bonding to other groups.

Examples of preferred combinations of X, Col and G in the above formula [ S3-X ] include combinations of the formula [ X1] with the formulae [ Col1] and [ G2], combinations of the formula [ X1] with the formulae [ Col2] and [ G2], combinations of the formula [ X2] with the formulae [ Col1] and [ G2], combinations of the formula [ X2] with the formulae [ Col2] and [ G2], and combinations of the formula [ X1] with the formulae [ Col3] and [ G1 ].

Specific examples of the formula [ S3] include a structure obtained by removing a hydroxyl group (hydroxyl group) from the steroid described in paragraph [0024] of Japanese patent application laid-open No. 4-281427, a structure obtained by removing an acid chloride group from the steroid described in paragraph [0030], a structure obtained by removing an amino group from the steroid described in paragraph [0038], a structure obtained by removing a halogen group from the steroid described in paragraph [0042] of Japanese patent application laid-open No. 8-146421, and structures described in paragraphs [0018] to [0022] of Japanese patent application laid-open No. 8-146421.

These diamines having specific side chain structures represented by the above formulas [ S1] to [ S3] may be used alone in 1 kind or in a mixture of 2 or more kinds. Depending on the properties required for the liquid crystal alignment film and the liquid crystal display element, 1 type or 2 or more types can be selected for use alone or in combination, and when 2 or more types are used in combination, the ratio thereof, etc. may be appropriately adjusted.

The diamine component of the present invention is a diamine containing a diamine having a structure represented by the above formula (1) and at least 1 kind of diamine having a specific side chain structure selected from the group represented by the above formulae [ S1] to [ S3 ].

Among them, as the diamine having a side chain structure selected from the group represented by the above formulas [ S1] to [ S3], for example, diamines having structures represented by the following formulas [1-S1] to [1-S3] and [2-S1] to [2-S3] are exemplified.

The above formula [1-S1]、[2-S1]In, X¹、X²、G¹、G²、R¹M and n are the same as the above formula [ S1]]The same is true in (1). The above formula [1-S2]、[2-S2]In, X³And R²And the above formula [ S2]The same is true in (1). The above formula [1-S3]、[2-S3]In, X⁴And R³And the above formula [ S3]The same is true in (1).

The diamines represented by the above formulas [1-S1] to [1-S3] include, for example, the following specific structures, but are not limited thereto.

Examples of the diamine represented by the above formulas [2-S1] to [2-S3] include, but are not limited to, the following specific structures.

< other diamines: diamine having photoreactive side chain >

The diamine component of the present embodiment may contain a diamine having a photoreactive side chain as another diamine. When the diamine component contains a diamine having a photoreactive side chain, the photoreactive side chain can be introduced into a specific polymer or a polymer other than the specific polymer.

Examples of the diamine having a photoreactive side chain include, but are not limited to, diamines represented by the following formulas [ VIII ] or [ IX ].

The above formula [ VIII]And [ IX]Middle, 2 amino (-NH)₂) The position of (b) may be any position on the benzene ring, and for example, the position of 2,3, the position of 2,4, the position of 2,5, the position of 2,6, the position of 3,4 or the position of 3,5 on the benzene ring is exemplified as the bonding group of the side chain. From the viewpoint of reactivity in synthesizing a polyamic acid, a position of 2,4, a position of 2,5, or a position of 3,5 is preferable. Also, in view of easiness in synthesizing the diamine, the 2,4 position or the 3,5 position is more preferable.

In addition, the above formula [ VIII]In, R⁸Represents a single bond, -CH₂-、-O-、-COO-、-OCO-、-NHCO-、-CONH-、-NH-、-CH₂O-、-N(CH₃)-、-CON(CH₃) -or-N (CH)₃) CO-. In particular, R⁸Preferably a single bond, -O-, -COO-, -NHCO-or-CONH-.

In addition, the above formula [ VIII]In, R⁹Represents an alkylene group having 1 to 20 carbon atoms which is optionally substituted with a single bond or a fluorine atom. Of alkylene groups herein-CH₂Optionally substituted by-CF₂-or-CH ═ CH-is optionally substituted by any of the following groups, where any of these groups are not adjacent to each other; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a 2-valent carbocyclic or heterocyclic ring. Specific examples of the 2-valent carbocycle or heterocycle include, but are not limited to, the following formula (1 a).

In addition, the above formula [ VIII]In, R⁹The organic polymer can be formed by a general organic synthesis method, but from the viewpoint of ease of synthesis, a single bond or an alkylene group having 1 to 12 carbon atoms is preferable.

In addition, the above formula [ VIII]In, R¹⁰Represents a photoreactive group selected from the group consisting of the following formula (1 b). Wherein, from the viewpoint of photoreactivity, R¹⁰Preferably a methacryloyl, acryloyl or vinyl group.

In addition, the above formula [ IX]In, Y₁represents-CH₂-, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-or-CO-. Y is₂Represents an alkylene group having 1 to 30 carbon atoms, a 2-valent carbocycle or heterocycle. 1 or more hydrogen atoms in the alkylene, 2-valent carbocyclic or heterocyclic ring herein are optionally substituted by fluorine atoms or organic groups. Y is₂In the case where the following groups are not adjacent to each other, -CH₂-optionally substituted by these groups; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, -NHCONH-, -CO-.

In addition, the above formula [ IX]In, Y₃represents-CH₂-, -O-, -CONH-, -NHCO-, -COO-, -OCO-, -NH-, -CO-or a single bond. Y is₄Represents a cinnamoyl group. Y is₅Represents a single bond, an alkylene group having 1 to 30 carbon atoms, or a 2-valent carbocyclic or heterocyclic ring. Here, 1 or more hydrogen atoms in the alkylene group, the 2-valent carbocyclic ring or the heterocyclic ring are optionally substituted by fluorine atoms or organic groups. Y is₅In the case where the following groups are not adjacent to each other, -CH₂-optionally substituted by these groups; -O-, -NHCO-, -CONH-, -COO-, -OCO-, -NH-, -NHCONH-, -CO-. Y is₆Represents a photopolymerizable group such as an acryloyl group or a methacryloyl group.

Specific examples of the diamine having a photoreactive side chain represented by the above formula [ VIII ] or [ IX ] include, but are not limited to, the following formula (1 c).

In the above formula (1c), X⁹And X¹⁰Each independently represents a single bond, -O-, -COO-, -NHCO-or-NH-. Y represents an alkylene group having 1 to 20 carbon atoms optionally substituted with a fluorine atom.

The diamine having a photoreactive side chain may also be a diamine of the following formula [ VII ]. The diamine of the formula [ VII ] has a site having a radical generating structure in a side chain. The radical generating structure is decomposed by ultraviolet irradiation to generate radicals.

In the formula [ VII ], Ar represents at least 1 aromatic hydrocarbon group selected from the group consisting of phenylene, naphthylene and biphenylene, and hydrogen atoms of the rings are optionally substituted by halogen atoms. Since Ar to which a carbonyl group is bonded is related to the absorption wavelength of ultraviolet light, a structure having a long conjugation length such as a naphthylene group or a biphenylene group is preferable in the case of a long wavelength. On the other hand, when Ar has a structure such as naphthylene or biphenylene, the solubility may be poor, and in this case, the difficulty of synthesis may be high. The most preferable Ar group is a phenyl group because sufficient characteristics can be obtained even when the wavelength of ultraviolet light is in the range of 250nm to 380 nm.

In Ar, the aromatic hydrocarbon group may have a substituent. Examples of the substituent herein are preferably electron-donating organic groups such as alkyl groups, hydroxyl groups, alkoxy groups, and amino groups.

In addition, the above formula [ VII]In, R₁And R₂Each independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a benzyl group or a phenethyl group. In the case of alkyl and alkoxy, R is optionally substituted₁And R₂Forming a ring.

In addition, the above formula [ VII]In, T₁And T₂Each independently represents a single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH₂O-、-N(CH₃)-、-CON(CH₃) -or-N (CH)₃) Bonding group of CO-.

In addition, formula [ VII]Wherein S represents a single bond, or an alkylene group having 1 to 20 carbon atoms which is unsubstituted or substituted with a fluorine atom. Of alkylene herein-CH₂-or-CF₂-optionally substituted by-CH ═ CH-optionally substituted by any of the groups listed below, where any of these groups are not adjacent to each other; -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, a 2-valent carbocycle, and a 2-valent heterocycle.

In the formula [ VII ], Q represents a structure selected from the following formula (1 d).

In the formula (1d), R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R₃represents-CH₂-, -NR-, -O-or-S-.

In the formula [ VII ], Q is preferably an electron-donating organic group, and is preferably an alkyl group, a hydroxyl group, an alkoxy group, an amino group or the like as exemplified for Ar. When Q is an amino derivative, since there is a possibility that a defect such as a salt formation between a carboxylic acid group and an amino group occurs when a polyamic acid which is a precursor of polyimide is polymerized, a hydroxyl group or an alkoxy group is more preferable.

In addition, the above formula [ VII]Middle, 2 amino (-NH)₂) The position of (b) may be any of o-phenylenediamine, m-phenylenediamine and p-phenylenediamine, and m-phenylenediamine or p-phenylenediamine is preferable from the viewpoint of reactivity with acid dianhydride.

Therefore, preferred specific examples of the formula [ VII ] include the following formulae from the viewpoints of ease of synthesis, high versatility, and characteristics. In the following formula, n is an integer of 2 to 8.

These diamines having a photoreactive side chain represented by the above formulas [ VII ], [ VIII ] or [ IX ] may be used alone in 1 kind or in a mixture of 2 or more kinds. Depending on the characteristics such as the liquid crystal alignment property, pretilt angle, voltage holding property, and accumulated charge when a liquid crystal alignment film is formed, the response speed of the liquid crystal when a liquid crystal display element is formed, it is sufficient to select 1 type or 2 or more types used in combination, and when 2 or more types are used in combination, the ratio thereof, and the like, can be appropriately adjusted.

In the present embodiment, when the diamine component contains a photoreactive side chain diamine, the photoreactive side chain diamine is preferably 10 to 70 mol%, more preferably 10 to 60 mol% of the total diamine components.

< other diamines: diamines other than the above

The other diamines that can be contained in the diamine component for obtaining a specific polymer are not limited to the diamines having a photoreactive side chain as described above. Examples of diamines other than the diamine having a photoreactive side chain include diamines represented by the following formula [2 ].

The above formula [2]In (A)₁And A₂Each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms or an alkynyl group having 2 to 5 carbon atoms. Wherein, from the viewpoint of reactivity of the monomer, A₁And A₂Preferably a hydrogen atom or a methyl group. In addition, if to Y₁Examples of the structure (D) include the following formulas (Y-1) to (Y-160), (Y162) to (Y-168), and (Y-170) to (Y-174).

In the above formula, n is an integer of 1 to 6 unless otherwise specified. In the above formula, Me represents a methyl group.

In the above formula, Boc represents a tert-butoxycarbonyl group.

The diamine having a photoreactive side chain can be used in combination of 1 kind or 2 or more kinds. When the diamine component contains other diamines, the amount of the specific diamine in the specific polymer relative to the other diamines may be as follows: the specific diamine is 5 to 80 mol%, preferably 10 to 70 mol%, and more preferably 20 to 70 mol%.

< tetracarboxylic acid component >

Examples of the tetracarboxylic acid component for obtaining the specific polymer include tetracarboxylic acid, tetracarboxylic dianhydride, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide, and these are also collectively referred to as the tetracarboxylic acid component in the present invention.

As the tetracarboxylic acid component, a tetracarboxylic dianhydride, a tetracarboxylic acid as a derivative thereof, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester or a tetracarboxylic acid dialkyl ester dihalide (these are collectively referred to as the 1st tetracarboxylic acid component.) may also be used.

Examples of the tetracarboxylic dianhydride include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. Specific examples thereof include those in the following groups [1] to [5], respectively.

[1] Aliphatic tetracarboxylic dianhydrides such as 1,2,3, 4-butanetetracarboxylic dianhydride and the like;

[2] examples of the alicyclic tetracarboxylic acid dianhydride include acid dianhydrides such as those represented by the following formulae (X1-1) to (X1-13):

in the above formulae (X1-1) to (X1-4), R₃～R₂₃Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a 1-valent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. R is_MRepresents a hydrogen atom or a methyl group. In the formula (X1-13), Xa represents a 4-valent organic group represented by the following formulae (Xa-1) to (Xa-7).

[3] 3-oxabicyclo [3.2.1] octane-2, 4-dione-6-spiro-3 ' - (tetrahydrofuran-2 ', 5 ' -dione), 3,5, 6-tricarboxyl-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 4, 9-dioxatricyclo [5.3.1.02,6] undecane-3, 5,8, 10-tetraone, and the like;

[4] examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic anhydride, 4,4 ' - (hexafluoroisopropylidene) diphthalic anhydride, 3 ', 4,4 ' -diphenylsulfone tetracarboxylic acid dianhydride, and acid dianhydrides represented by the following formulae (Xb-1) to (Xb-10), and

[5] acid dianhydrides represented by the formulae (X1-44) to (X1-52) and tetracarboxylic acid dianhydrides described in Japanese patent application laid-open No. 2010-97188.

The tetracarboxylic acid component described above can be used alone in 1 kind, or in a mixture of 2 or more kinds. Depending on the properties required for the liquid crystal alignment film and the liquid crystal display element, 1 type or 2 or more types can be selected for use alone or in combination, and when 2 or more types are used in combination, the ratio thereof, etc. may be appropriately adjusted.

< method for producing specific Polymer >

The specific polymer can be obtained by a method of reacting the diamine component (diamine component composed of a plurality of kinds of diamines) of the present embodiment described above with a tetracarboxylic acid component. Examples of the method include the following: a diamine component consisting of 1 or more kinds of diamines is reacted with at least 1 tetracarboxylic acid component selected from the group consisting of tetracarboxylic dianhydride and tetracarboxylic acid derivatives thereof to obtain polyamic acid. Specifically, a method of polycondensing a primary diamine or a secondary diamine with a tetracarboxylic dianhydride to obtain a polyamic acid can be used.

In order to obtain the polyamic acid alkyl ester, a method of polycondensing a tetracarboxylic acid obtained by dialkylesterifying a carboxylic acid group with a primary diamine or a secondary diamine, a method of polycondensing a tetracarboxylic acid dihalide obtained by halogenating a carboxylic acid group with a primary diamine or a secondary diamine, or a method of converting the carboxyl group of a polyamic acid into an ester can be employed. In order to obtain polyimide, a method of ring closure of the polyamic acid or polyamic acid alkyl ester described above to form polyimide may be used.

The reaction of the diamine component with the tetracarboxylic acid component is usually carried out in a solvent. The solvent used in this case is not particularly limited as long as it dissolves the polyimide precursor formed. Examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ -butyrolactone, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and 1, 3-dimethyl-imidazolidinone. When the polyimide precursor has high solubility in a solvent, a solvent represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent represented by the following formulae [ D-1] to [ D-3], or the like can be used.

Formula [ D-1]In (D)¹Represents an alkyl group having 1 to 3 carbon atoms.Formula [ D-2]In (D)²Represents an alkyl group having 1 to 3 carbon atoms. Formula [ D-3]In (D)³Represents an alkyl group having 1 to 4 carbon atoms.

These solvents may be used alone in 1 kind, or in a mixture of 2 or more kinds. Even in the case of a solvent which does not dissolve the polyimide precursor, the solvent may be mixed with the polyimide precursor in a range where the polyimide precursor to be produced does not precipitate. Further, the solvent is preferably used after dehydration and drying because the water content in the solvent inhibits the polymerization reaction and further causes hydrolysis of the polyimide precursor to be produced.

When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the following methods may be mentioned: a method of stirring a solution obtained by dispersing or dissolving a diamine component in a solvent, and adding a tetracarboxylic acid component directly or after dispersing or dissolving a tetracarboxylic acid component in a solvent; conversely, a method of adding a diamine component to a solution obtained by dispersing or dissolving a tetracarboxylic acid component in a solvent; a method of alternately adding a diamine component and a tetracarboxylic acid component, and any of these methods can be used. When a plurality of diamine components or tetracarboxylic acid components are used and reacted, they may be reacted in a state of being mixed in advance, or may be reacted in sequence, or low molecular weight materials obtained by the respective reactions may be mixed and reacted to produce a polymer.

The temperature for polycondensation of the diamine component and the tetracarboxylic acid component may be selected from any temperature within the range of-20 to 150 ℃, and preferably within the range of-5 to 100 ℃. The reaction can be carried out at any concentration, but if the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and if the concentration is too high, the viscosity of the reaction solution becomes too high, and uniform stirring becomes difficult. Therefore, the amount is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be carried out at a high concentration at the initial stage of the reaction, and then a solvent may be added.

In the polymerization reaction of the polyimide precursor, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2. Similarly to the ordinary polycondensation reaction, the molecular weight of the polyimide precursor to be produced increases as the molar ratio approaches 1.0.

The polyimide is obtained by ring-closing the polyimide precursor, and the ring-closing ratio of the amic acid group (also referred to as imidization ratio) of the polyimide does not necessarily need to be 100%, and can be arbitrarily adjusted depending on the application and purpose. Examples of the method for imidizing the polyimide precursor include: thermal imidization in which a solution of a polyimide precursor is directly heated, or catalytic imidization in which a catalyst is added to a solution of a polyimide precursor.

The temperature at which the polyimide precursor is thermally imidized in the solution is 100 to 400 ℃, preferably 120 to 250 ℃, and it is preferable to perform thermal imidization while removing water generated by the imidization reaction from the system. The catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at-20 to 250 ℃, preferably at 0 to 180 ℃.

The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, the amount of the acid amide group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has basicity suitable for promoting the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. In particular, acetic anhydride is preferred because it is easy to purify the reaction product after the completion of the reaction. The imidization rate based on the catalytic imidization can be controlled by adjusting the amount of the catalyst, the reaction temperature, and the reaction time.

When the polyimide precursor or polyimide to be produced is recovered from the reaction solution of the polyimide precursor or polyimide, the reaction solution may be put into a solvent to precipitate the polyimide. Examples of the solvent used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by charging the solvent may be recovered by filtration, and then dried under normal pressure or reduced pressure, or under normal temperature or heating. Further, if the operation of dissolving the polymer recovered by precipitation in the solvent again and recovering the polymer by precipitation is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the solvent in this case include alcohols, ketones, and hydrocarbons. If more than 3 solvents selected from them are used, the purification efficiency is further improved, and therefore, it is preferable.

Examples of more specific methods for producing the polyamic acid alkyl ester of the present invention are shown in the following (1) to (3).

(1) Method for producing polyamide acid by esterification reaction of polyamide acid

This method is, for example, a method of producing a polyamic acid alkyl ester by producing a polyamic acid from a diamine component and a tetracarboxylic acid component and subjecting a carboxyl group (COOH group) thereof to a chemical reaction, that is, an esterification reaction. The esterification reaction is a method of reacting polyamic acid with an esterifying agent in the presence of a solvent at-20 to 150 ℃ (preferably 0 to 50 ℃) for 30 minutes to 24 hours (preferably 1 to 4 hours).

As the above-mentioned esterifying agent, preferred is an esterifying agent which can be easily removed after the esterification reaction, and examples thereof include N, N-dimethylformamide dimethyl acetal, N-dimethylformamide diethyl acetal, N-dimethylformamide dipropyl acetal, N-dimethylformamide dineopentylbutyl acetal, N-dimethylformamide di-tert-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, and 4- (4, 6-dimethoxy-1, 3, 5-triazin-2-yl) -4-methylchloromorpholine. The amount of the esterifying agent to be used is preferably 2 to 6 molar equivalents based on 1 mole of the repeating unit of the polyamic acid. Among them, 2 to 4 molar equivalents are preferable.

The solvent used in the esterification reaction may be a solvent used in the reaction of the diamine component and the tetracarboxylic acid component, from the viewpoint of solubility of the polyamic acid in the solvent. Among them, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone is preferable. These solvents may be used in 1 kind or in combination of 2 or more kinds. The concentration of the polyamic acid in the solvent for the esterification reaction is preferably 1 to 30% by mass from the viewpoint that the polyamic acid is less likely to precipitate. Among them, it is preferably 5 to 20% by mass.

(2) Method for producing a tetracarboxylic acid diester by reacting a diamine component with a tetracarboxylic acid diester diacid chloride

The method is, for example, a method of reacting a diamine component with a tetracarboxylic acid diester diacid chloride in the presence of a base and a solvent at-20 to 150 ℃ (preferably 0 to 50 ℃) for 30 minutes to 24 hours (preferably 1 to 4 hours). As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used. Among them, pyridine is preferable for the mild and smooth reaction. The amount of the base to be used is preferably an amount which can be easily removed after the reaction, and is preferably 2 to 4 times by mol relative to the tetracarboxylic acid diester diacid chloride. Among them, the molar ratio is more preferably 2 to 3 times.

The solvent used in the reaction of the diamine component and the tetracarboxylic acid component is exemplified from the viewpoint of solubility of the obtained polymer, i.e., polyamic acid alkyl ester in the solvent. Among them, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone is preferable. These solvents may be used alone in 1 kind, or in combination of 2 or more kinds.

The concentration of the polyamic acid alkyl ester in the reaction solvent is preferably 1 to 30% by mass from the viewpoint that the polyamic acid alkyl ester is less likely to precipitate. Among them, it is preferably 5 to 20% by mass. In order to prevent hydrolysis of the tetracarboxylic acid diester diacid chloride, the solvent used to prepare the polyamic acid alkyl ester is preferably dehydrated as much as possible. Further, the reaction is preferably carried out in a nitrogen atmosphere to prevent the mixing of external gas.

(3) Method for producing a tetracarboxylic acid diester by reacting a diamine component with a tetracarboxylic acid diester

This method is, for example, a method of subjecting a diamine component and a tetracarboxylic acid diester to a polycondensation reaction in the presence of a condensing agent, a base and a solvent at 0 to 150 ℃ (preferably 0 to 100 ℃) for 30 minutes to 24 hours (preferably 3 to 15 hours).

As the condensing agent, triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N ' -carbonyldiimidazole, dimethoxy-1, 3, 5-triazinylmethyl morpholine, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N ' -tetramethyluronium hexafluorophosphate, diphenyl (2, 3-dihydro-2-thia-3-benzoxazolyl) phosphonate, and the like can be used. The amount of the condensing agent to be used is preferably 2 to 3 times by mol, and particularly preferably 2 to 2.5 times by mol, based on the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be used is preferably an amount which can be easily removed after the polycondensation reaction, and is preferably 2 to 4 times by mol, more preferably 2 to 3 times by mol, based on the diamine component. The solvent used in the polycondensation reaction may be a solvent used in the reaction between the diamine component and the tetracarboxylic acid component, from the viewpoint of solubility of the obtained polymer, i.e., polyamic acid alkyl ester in the solvent. Among them, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone is preferable. These solvents may be used in a single amount of 1 kind or in a mixture of 2 or more kinds.

In addition, in the polycondensation reaction, by adding a lewis acid as an additive, the reaction proceeds efficiently. As the lewis acid, lithium halide such as lithium chloride or lithium bromide is preferable. The amount of the lewis acid to be used is preferably 0.1 to 10 times by mol based on the diamine component. Among them, the amount of the compound is preferably 2.0 to 3.0 times by mol.

When the polyamic acid alkyl ester is recovered from the polyamic acid alkyl ester solution obtained by the above methods (1) to (3), the reaction solution may be put into a solvent to precipitate the polyamic acid alkyl ester. Examples of the solvent used for precipitation include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, and toluene. The polymer to be precipitated by charging the solvent is preferably subjected to a washing operation with the solvent a plurality of times for the purpose of removing the additives and catalysts used. After washing and filtration for recovery, the polymer may be dried under normal pressure or reduced pressure, or under normal temperature or heating. Further, the operation of dissolving the polymer recovered by precipitation in the solvent again and recovering the polymer by precipitation is repeated 2 to 10 times, whereby impurities in the polymer can be reduced. The polyamic acid alkyl ester is preferably produced by the process (2) or (3).

< liquid Crystal Aligning agent >

The liquid crystal aligning agent of the present invention contains the above-mentioned specific polymer, but may contain 2 or more specific polymers having different structures. In addition to the specific polymer, other polymers, that is, polymers not having a 2-valent group represented by the formula (1) (polymers obtained when the specific diamine represented by the formula (1) is not contained) may be contained. Examples of the polymer form include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or a derivative thereof, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate. When the liquid crystal aligning agent of the present invention contains another polymer, the proportion of the specific polymer to the whole polymer component is preferably 5% by mass or more, and examples thereof include 5 to 95% by mass.

The liquid crystal aligning agent is generally used in the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal aligning agent of the present invention is also preferably a coating solution containing the above-mentioned polymer component and an organic solvent capable of dissolving the polymer component. In this case, the concentration of the polymer in the liquid crystal aligning agent may be appropriately changed in accordance with the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. The concentration of the polymer is particularly preferably 2 to 8 mass%.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it is an organic solvent in which the polymer component can be uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ -butyrolactone, 1, 3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, and cyclopentanone. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ -butyrolactone is preferably used.

In addition to the above-mentioned solvents, the organic solvent contained in the liquid crystal aligning agent of the present invention may be a solvent which can improve coatability when the liquid crystal aligning agent is coated and surface smoothness of a coating film. Specific examples of the organic solvent are listed below, but not limited to these examples.

For example, ethanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentanol, tert-pentanol, 3-methyl-2-butanol, neopentanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2, 6-dimethyl-4-heptanol, isobutanol, 2-pentanol, 2-methyl-1-hexanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 2-methyl-1-hexanol, 3-methyl-cyclohexanol, 2, 6-dimethyl-4-heptanol, 2-butanol, 2-methyl-2-hexanol, 2-methyl-2, 2-methyl-1-2, 2-methyl-1-hexanol, 2, 6-methyl-4-heptanol, 2,3, 2,4, 2, or a, 2,4, 2,4, 3,2, 3,2, 1, 2-ethanediol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethyl-1, 3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1, 2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2, 6-dimethyl-4-heptanone, 4, 6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol ether, propylene glycol ether, and mixtures thereof, Dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionate, 3-methoxypropionic acid, propyl 3-methoxypropionate, propylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, triethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propylene glycol monopropyl acetate, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol, Butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and solvents represented by the above formulae [ D-1] to [ D-3 ].

Among them, 1-hexanol, cyclohexanol, 1, 2-ethylene glycol, 1, 2-propylene glycol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, or dipropylene glycol dimethyl ether is preferably used as the organic solvent. The kind and content of the solvent can be appropriately selected depending on the coating apparatus, coating conditions, coating environment, and the like of the liquid crystal aligning agent.

The liquid crystal aligning agent of the present invention may further contain components other than the polymer component and the organic solvent. Examples of such additional components include: an adhesion promoter for improving adhesion between the liquid crystal alignment film and the substrate and adhesion between the liquid crystal alignment film and the sealing material; a crosslinking agent for improving the strength of the liquid crystal alignment film; a dielectric or conductive substance for adjusting the dielectric constant and resistance of the liquid crystal alignment film. Specific examples of such additional components include poor solvents and crosslinkable compounds disclosed in International publication No. 2015/060357, page 53, paragraph [0104] to page 60, paragraph [0116 ].

The liquid crystal aligning agent of the present invention may contain, in addition to the above, a polymer other than the specific polymer described in the present invention; a dielectric for changing electric characteristics such as a dielectric constant and conductivity of the liquid crystal alignment film; a silane coupling agent for improving the adhesion between the liquid crystal alignment film and the substrate; a crosslinkable compound for improving the hardness and density of the film when the liquid crystal alignment film is formed; and an imidization accelerator for effectively performing imidization by heating the polyimide precursor when the coating film is fired.

Examples of the compound for improving the adhesion between the liquid crystal alignment film and the substrate include a functional silane-containing compound and an epoxy-containing compound, and examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, and mixtures thereof, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, 4, 7-triazadene, 10-triethoxysilyl-1, 4, 7-triazadene, 9-trimethoxysilyl-3, 6-diazainonyl acetate, 9-triethoxysilyl-3, 6-diazainonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-trimethoxy-1, 4-triethoxysilyl-1, 4, 7-triazadene, N-trimethoxysilyl-3, 6-diazainonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-trimethoxy-methyl-ethyl-3-trisilane, N-trimethoxy-ethyl-1, N-trimethoxy-ethyl-1-ethyl-acetate, and N-ethyl-1, and, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-tetraglycidyl-2, 4-hexanediol, N, n ', -tetraglycidyl-m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N ', -tetraglycidyl-4, 4 ' -diaminodiphenylmethane, and the like.

In addition, the following additives may be added to the liquid crystal aligning agent of the present invention in order to improve the mechanical strength of the liquid crystal alignment film.

The additive is preferably 0.1 to 30 parts by mass per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. If the amount is less than 0.1 part by mass, no effect is expected, and if the amount exceeds 30 parts by mass, the orientation of the liquid crystal is lowered, and therefore, the amount is more preferably 0.5 to 20 parts by mass.

< liquid Crystal alignment film >

The liquid crystal alignment film of the present invention is obtained from the liquid crystal aligning agent. The use of the liquid crystal aligning agent of the present invention can provide a liquid crystal alignment film and a liquid crystal display device which are particularly suitable for the VA system, particularly the PSA mode, in which liquid crystal molecules aligned vertically to a substrate are responded by an electric field, and which have excellent voltage holding ratio, rapid relaxation of accumulated charges, and excellent afterimage characteristics. In 1 example of the method for obtaining a liquid crystal alignment film, the liquid crystal alignment agent of the present invention may be applied to a substrate, and then dried and fired as necessary, and the cured film obtained thereby may be used as a liquid crystal alignment film as it is. The cured film may be subjected to brushing, irradiation with polarized light, light of a specific wavelength, or the like, treatment with an ion beam, or the like, or irradiation with UV as an alignment film for PSA in a state where a voltage is applied to the liquid crystal display element filled with liquid crystal. In particular, it is useful as an alignment film for PSA.

The substrate to which the liquid crystal aligning agent is applied is not particularly limited as long as it is a substrate having high transparency, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acryl substrate or a polycarbonate substrate, or the like can be used. In this case, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed, in view of simplifying the process. In the reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used as long as it is a single-sided substrate, and a material that reflects light such as aluminum may be used as an electrode in this case.

The method of applying the liquid crystal aligning agent is not particularly limited, and the method is generally industrially screen printing, offset printing, flexographic printing, ink jet method, or the like. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray method, and the like, and these methods can be used according to the purpose. After coating the liquid crystal alignment agent on the substrate, the solvent is evaporated by heating means such as a hot plate, a thermal cycle oven, or an IR (infrared) oven, and then fired. The drying and firing steps after the application of the liquid crystal aligning agent can be performed at any temperature and for any time. The drying step is not essential, and when the time from coating to firing is not constant or the firing is not performed immediately after coating, the drying step is preferably performed. The drying is not particularly limited as long as the solvent is removed to such an extent that the shape of the coating film is not deformed by conveyance of the substrate or the like. For example, the drying may be carried out by drying the mixture on a hot plate at a temperature of 40 to 150 ℃ and preferably 60 to 100 ℃ for 0.5 to 30 minutes and preferably 1 to 5 minutes.

The firing temperature of the coating film formed by applying the liquid crystal aligning agent is not limited, and is, for example, 100 to 350 ℃, preferably 120 to 300 ℃, and more preferably 150 to 250 ℃. The firing time is 5 to 240 minutes, preferably 10 to 90 minutes, and more preferably 20 to 90 minutes. The heating may be performed by a generally known method such as a hot plate, a hot air circulation furnace, an infrared furnace, or the like.

If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display device may be lowered, and therefore, 5 to 300nm is preferable, and 10 to 200nm is more preferable. The liquid crystal alignment film of the present invention is useful as a liquid crystal alignment film for a liquid crystal display element of a VA system, particularly a PSA mode.

< liquid crystal display element and method for manufacturing the same >

In the liquid crystal display element, a liquid crystal alignment film may be formed on a substrate by the above-described method, and then a liquid crystal cell may be produced by a known method. A specific example of the liquid crystal display element is a vertical alignment type liquid crystal display element including a liquid crystal cell having: the liquid crystal display device includes 2 substrates arranged in an opposing manner, a liquid crystal layer provided between the substrates, and the liquid crystal alignment film provided between the substrates and the liquid crystal layer and formed of a liquid crystal alignment agent. Specifically, the liquid crystal display element of the vertical alignment type is provided with a liquid crystal cell manufactured as follows: a liquid crystal cell was produced by applying a liquid crystal aligning agent to 2 substrates and firing the liquid crystal aligning agent to form a liquid crystal alignment film, arranging the 2 substrates so that the liquid crystal alignment film faces the liquid crystal alignment film, sandwiching a liquid crystal layer made of liquid crystal between the 2 substrates, placing the liquid crystal layer in contact with the liquid crystal alignment film, and irradiating ultraviolet rays while applying a voltage to the liquid crystal alignment film and the liquid crystal layer.

The substrate of the liquid crystal display element is not particularly limited as long as it is a substrate having high transparency, and is usually a substrate on which a transparent electrode for driving liquid crystal is formed. Specific examples thereof include the same substrates as those described in the liquid crystal alignment film. However, since the liquid crystal display element uses the liquid crystal aligning agent containing the polyimide-based polymer of the present invention, the liquid crystal display element can be operated without forming a slit pattern or a protrusion pattern on the opposite substrate even if a line/slit electrode pattern of, for example, 1 μm to 10 μm is formed on one substrate, and the liquid crystal display element having such a structure can be manufactured by a simplified process and can obtain a high transmittance.

In addition, in a high-functional element such as a TFT-type element, a product in which an element such as a transistor is formed between an electrode for driving liquid crystal and a substrate can be used.

In the case of a transmissive liquid crystal display element, the above-described substrate is generally used, but in the case of a reflective liquid crystal display element, if only a single-sided substrate is used, an opaque substrate such as a silicon wafer may be used. In this case, a material such as aluminum that reflects light may be used for the electrodes formed on the substrate.

The liquid crystal material constituting the liquid crystal layer of the liquid crystal display element is not particularly limited, and a liquid crystal material conventionally used in a vertical alignment system, for example, a negative type liquid crystal such as MLC-6608, MLC-6609, or MLC-3023 manufactured by merck corporation, can be used. In the PSA system, for example, a liquid crystal containing a polymerizable compound represented by the following formula can be used.

As a method of sandwiching a liquid crystal layer between 2 substrates, a known method can be cited. Examples of the method include the following methods: the method includes preparing 1 pair of substrates on which liquid crystal alignment films are formed, spreading spacers such as beads on the liquid crystal alignment film of one substrate, attaching the other substrate so that the surface on which the liquid crystal alignment film is formed is the inner side, injecting liquid crystal under reduced pressure, and sealing. In addition, a liquid crystal cell can also be produced by the following method: the method includes preparing 1 pair of substrates on which liquid crystal alignment films are formed, dispersing spacers such as beads on the liquid crystal alignment film of one substrate, dropping liquid crystal, and then attaching the other substrate so that the surface on which the liquid crystal alignment film is formed is the inner side, and sealing. The thickness of the spacer is preferably 1 to 30 μm, and more preferably 2 to 10 μm.

As the step of producing a liquid crystal cell by irradiating ultraviolet rays while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, for example, a method of applying an electric field to the liquid crystal alignment film and the liquid crystal layer by applying a voltage between electrodes provided on the substrate and irradiating ultraviolet rays while maintaining the electric field can be cited. The voltage applied between the electrodes is, for example, 5 to 30Vp-p, preferably 5 to 20 Vp-p. The irradiation amount of ultraviolet rays is, for example, 1 to 60J, preferably 40J or less, and a small irradiation amount of ultraviolet rays is preferable because it is possible to suppress a decrease in reliability due to breakage of a member constituting the liquid crystal display element, and it is possible to reduce the irradiation time of ultraviolet rays and improve the manufacturing efficiency.

As described above, when ultraviolet rays are irradiated while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, the polymerizable compound reacts to form a polymer, and the polymer memorizes the tilt direction of the liquid crystal molecules, thereby increasing the response speed of the obtained liquid crystal display element. Further, when ultraviolet rays are irradiated while applying a voltage to the liquid crystal alignment film and the liquid crystal layer, photoreactive side chains of at least one polymer selected from a polyimide precursor having a side chain for vertically aligning a liquid crystal and a photoreactive side chain and a polyimide obtained by imidizing the polyimide precursor react with each other, and the photoreactive side chains of the polymer react with the polymerizable compound, so that the response speed of the obtained liquid crystal display element can be increased.

Next, a polarizing plate is provided. Specifically, 1 pair of polarizing plates is preferably attached to the surface of 2 substrates opposite to the liquid crystal layer.

The liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above-described configuration or manufacturing method as long as the liquid crystal alignment agent of the present invention is used, and may be manufactured by other known methods. The steps from the liquid crystal aligning agent to the production of the liquid crystal display element are disclosed in, for example, Japanese patent laid-open publication No. 2015-135393 from page 17 [0074] to page 19 [0082 ].

When the polymer has a photoreactive side chain, the polymerizable compound is polymerized and the photoreactive side chains are reacted with each other, whereby the photoreactive side chain of the polymer is reacted with the polymerizable compound, whereby the alignment of the liquid crystal can be fixed more effectively and the liquid crystal display element having an excellent response speed can be obtained.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The compounds used are as follows.

(liquid Crystal) MLC-3023 (negative type liquid Crystal containing polymerizable Compound, manufactured by Merck)

(specific diamine)

Compounds represented by the following formulae [ A1] to [ A6]

A1: a compound represented by the formula [ A1]

A2: a compound represented by the formula [ A2]

A3: a compound represented by the formula [ A3]

A4: a compound represented by the formula [ A4]

A5: a compound represented by the formula [ A5]

A6: a compound represented by the formula [ A6]

A7: a compound represented by the formula [ A7]

(diamine having a specific side chain structure)

Compounds represented by the following formulae [ B1] to [ B3]

B1: a compound represented by the formula [ B1]

B2: a compound represented by the formula [ B2]

B3: a compound represented by the formula [ B3]

(other diamines)

Compounds represented by the following formulae [ C1] to [ C5]

C1: a compound represented by the formula [ C1]

C2: a compound represented by the formula [ C2]

C3: a compound represented by the formula [ C3]

C4: a compound represented by the formula [ C4]

C5: a compound represented by the formula [ C5]

(tetracarboxylic acid component)

Compounds represented by the following formulae [ D1] to [ D3]

D1: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride

D2: bicyclo [3,3,0] octane-2, 4,6, 8-tetracarboxylic dianhydride

D3: 3,3 ', 4, 4' -benzophenone tetracarboxylic dianhydride

D4: a compound represented by the formula [ D4]

(solvent)

NMP: n-methyl-2-pyrrolidone

BCS (B cell culture system): ethylene glycol monobutyl ether

γ BL: gamma-butyrolactone

< Synthesis of A2, A4 and A5 >

A2, A4 and A5 are novel compounds which are not disclosed in documents and the like, and the synthesis method will be described in detail below.

The following [ Synthesis example A-1][ Synthesis example A-3]The product is passed through¹H-NMR analysis was carried out for identification (analysis conditions are as follows).

The device comprises the following steps: varian NMR System 400NB (400MHz)

And (3) determination of a solvent: CDCl₃，DMSO-d₆

Reference substance: tetramethylsilane (TMS) (delta 0.0ppm based on¹H)

[ Synthesis example A-1 ]: synthesis of A4

< Synthesis of Compound [1] in the reaction formula >

After zinc chloride (295.6g) was dried under vacuum at 100 ℃ for 1 hour to remove water, toluene (742.0g), diethylamine (111.4g), tert-butanol (120.2g), 3' -nitroacetophenone (251.8g) were added to bring the internal temperature to 42 ℃. Subsequently, 2-bromo-3' -nitroacetophenone (247.3g, 1.01mol) dissolved in tetrahydrofuran (494.6g) was added dropwise over 90 minutes, and the reaction was carried out at an internal temperature of 45 ℃ for 16 hours. After completion of the reaction, sulfuric acid (49.7g) and pure water (939.7g) were poured into the reaction mixture to precipitate crystals, which were filtered, and the filtrate was washed 3 times with a mixed solvent of tetrahydrofuran (247.3g) and pure water (247.3g) and dried to obtain 275.7g of the compound [1] (yield: 83%, property: pale yellow crystals).

< Synthesis of Compound [2] in the reaction formula >

Compound [1] (27.6g, 84.1mmol) and methylamine (about 7% tetrahydrofuran solution, about 2mol/L, 100mL) were put into tetrahydrofuran (110.7g) and ethanol (84.6g), and acetic acid (25.5g) was added under ice-cooling in a nitrogen atmosphere. After addition of acetic acid, the reaction was performed under reflux conditions in a nitrogen atmosphere for 24 hours. After the reaction, pure water (276.0g) was added to precipitate crystals, which were filtered, and the filtrate was washed 3 times with methanol (55.2g) and dried to obtain 26.0g of compound [2] (yield: 96%, property: light orange crystals).

< Synthesis of A4 >

Compound [2] (26.0g, 80.5mmol) and 5% palladium on carbon (2.1g) were put in tetrahydrofuran (216.2g), and reacted at 40 ℃ in a hydrogen atmosphere for about 3 days. After completion of the reaction, filtration and concentration under reduced pressure were carried out so that the total internal weight became 42.3 g. Subsequently, methanol (104.0g) was added to precipitate crystals, which were then filtered and dried to obtain A417.4g (yield: 82%, property: white crystals).

¹H-NMR (400MHz) in DMSO-d₆The method comprises the following steps: 3.53ppm (s, 3H), 5.13ppm (s, 4H), 6.12ppm (s, 2H), 6.50-6.53ppm (m, 2H), 6.60-6.62ppm (m, 2H), 6.67ppm (t, J ═ 1.8Hz, 2H), 7.07ppm (t, J ═ 7.8Hz, 2H)

[ Synthesis example A-2 ]: synthesis of A5

< Synthesis of Compound [3] in the reaction formula >

The compound [1] (243.2g, 741mmol) and ammonium acetate (286.0g) were charged into tetrahydrofuran (1702g), and reacted under reflux in a nitrogen atmosphere for 22 hours. After the reaction, pure water (1702g) was added to precipitate crystals, which were filtered, and the filtrate was washed 2 times with a mixed solution of tetrahydrofuran (243g) and pure water (243g), followed by washing 2 times with methanol (365g), and dried to obtain 194.5g of the compound [3] (yield: 85%, property: orange crystals).

< Synthesis of Compound [4] in the reaction formula >

Compound [3] (22.7g, 73.3mmol) and 4-dimethylaminopyridine (0.44g) were charged into tetrahydrofuran (159.3g), and di-tert-butyl dicarbonate (18.4g) dissolved in tetrahydrofuran (11.3g) was added dropwise under a nitrogen atmosphere at room temperature to react at the same temperature for 5 hours. After completion of the reaction, methanol (90.8g) was added thereto, and the mixture was stirred under ice-cooling, filtered and washed with methanol to obtain 28.6g of the compound [4] (yield: 95%, property: pale yellow crystal).

< Synthesis of A5 >

Compound [4] (28.6g, 69.9mmol) and 5% palladium on carbon (2.20g) were put in tetrahydrofuran (257.4g) and reacted at 40 ℃ in a hydrogen atmosphere for about 3 days. After completion of the reaction, the reaction mixture was filtered and concentrated under reduced pressure so that the total internal weight became 41.6 g. Subsequently, 2-propanol (114.4g) was added to precipitate crystals, which were then filtered and dried to obtain A512.8g (yield: 52%, property: white crystals).

¹H-NMR (400MHz) in DMSO-d₆The method comprises the following steps: 1.23ppm (s, 9H), 5.12ppm (s, 4H), 6.14ppm (s, 2H), 6.44-6.46ppm (m, 2H), 6.51-6.53ppm (m, 4H), 6.99-7.03ppm (m, 2H).

[ Synthesis examples A-3 ]: synthesis of A2

< Synthesis of Compound [5] in the reaction formula >

The synthesis was carried out in the same manner as in the synthesis of the compound [1] except that 3 '-nitroacetophenone as a starting material was changed to 4' -nitroacetophenone, and 2-bromo-3 '-nitroacetophenone was changed to 2-bromo-4' -nitroacetophenone.

< Synthesis of Compound [6] in the reaction formula >

The synthesis was carried out by the same method as in the synthesis of the compound [3] except that the compound [1] was changed to the compound [5 ].

< Synthesis of Compound [7]

The synthesis was carried out by the same method as in the synthesis of the compound [4] except that the compound [3] was changed to the compound [6 ].

< Synthesis of A2 >

The synthesis was carried out in the same manner as in the synthesis of a5, except that the compound [4] was changed to the compound [7 ].

¹H-NMR (400MHz) in CDCl₃The method comprises the following steps: 1.21ppm (s, 9H), 3.69ppm (s, 4H), 6.12ppm (s, 2H), 6.67-6.69ppm (m, 4H), 7.17-7.26ppm (m, 4H).

(measurement of imidization ratio of polyimide)

20mg of the polyimide powder was put into an NMR (nuclear magnetic resonance) sample tube (. phi.5 (manufactured by Softweed scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53ml) was added thereto, and the mixture was completely dissolved by applying ultrasonic waves. The solution was subjected to 500MHz proton NMR measurement using an NMR spectrometer (JNW-ECA500) (JEOL DATUM). The imidization ratio is determined by the following calculation formula using the peak integral value of the proton derived from the structure which does not change before and after imidization as a reference proton and the peak integral value of the proton derived from the NH group of amic acid appearing in the vicinity of 9.5 to 10.0 ppm.

Imidization ratio (%) - (1-. alpha.x/y). times.100

In the above calculation formula, x represents a peak integrated value of a proton derived from the NH group of amic acid, y represents a peak integrated value of a reference proton, and α represents a ratio of the number of reference protons to 1 proton of the NH group of amic acid in the case of polyamic acid (imidization ratio of 0%).

(measurement of viscosity)

In the synthesis examples or comparative synthesis examples, the viscosity of the polyimide polymer was measured using an E-type viscometer TVE-22H (manufactured by Toyobo Co., Ltd.) at a sample volume of 1.1mL, a conical rotor TE-1(1 ℃ C., 34', R24) and a temperature of 25 ℃.

< Synthesis of polyimide-based Polymer >

[ Synthesis example 1]

D2(2.50g, 10.0mmol), A1(3.49g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (31.9g) and gamma BL (8.0g) and reacted at 50 ℃ for 3 hours, then D1(1.70g, 8.66mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 759 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.99g) and pyridine (1.24g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (234ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (1). The imidization ratio of this polyimide was 54.1%.

[ Synthesis example 2]

D2(2.50g, 10.0mmol), A1(3.99g, 16.0mmol) and B2(1.74g, 4.00mmol) were mixed with NMP (31.8g) and gamma BL (7.9g) and reacted at 50 ℃ for 3 hours, then D1(1.69g, 8.60mmol) was added thereto and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 1122 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (4.01g) and pyridine (1.24g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (234ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (2). The imidization ratio of this polyimide was 54.6%.

[ Synthesis example 3]

D2(2.50g, 10.0mmol), A2(4.89g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (45.8g) and reacted at 50 ℃ for 3 hours, then D1(1.76g, 8.98mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 728mPa · s.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.51g) and pyridine (1.09g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (232ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (3). The imidization ratio of this polyimide was 46.9%.

[ Synthesis example 4]

D2(2.50g, 10.0mmol), A3(3.49g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (40.2g) and reacted at 50 ℃ for 3 hours, then D1(1.76g, 9.00mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 758mPa · s.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.99g) and pyridine (1.24g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (234ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (4). The imidization ratio of this polyimide was 46.1%.

[ Synthesis example 5]

D2(2.50g, 10.0mmol), A4(3.69g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (41.7g) and reacted at 50 ℃ for 3 hours, then D1(1.95g, 9.94mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 805 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.91g) and pyridine (1.21g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (233ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (5). The imidization ratio of this polyimide was 56.4%.

[ Synthesis example 6]

D2(2.50g, 10.0mmol), A5(4.89g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (46.5g) and reacted at 50 ℃ for 3 hours, then D1(1.95g, 9.94mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 461mPa · s.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.51g) and pyridine (1.09g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (232ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (6). The imidization rate of this polyimide was 53.6%.

[ Synthesis example 7]

D2(2.50g, 10.0mmol), A1(2.49g, 10.0mmol), B2(3.48g, 8.00mmol) and C1(0.66g, 2.00mmol) were mixed with NMP (43.6g) and reacted at 50 ℃ for 3 hours, then D1(1.78g, 9.06mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 693 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.68g) and pyridine (1.14g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (232ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (7). The imidization ratio of this polyimide was 55.9%.

[ Synthesis example 8]

D2(2.50g, 10.0mmol), A6(3.79g, 8.00mmol), B1(2.28g, 6.00mmol) and C2(0.91g, 6.00mmol) were mixed with NMP (45.1g) and reacted at 50 ℃ for 3 hours, then D1(1.79g, 9.12mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 740 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.57g) and pyridine (1.11g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (232ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (8). The imidization ratio of this polyimide was 50.5%.

[ Synthesis example 9]

D2(2.50g, 10.0mmol), A3(1.75g, 7.00mmol), B3(3.79g, 5.00mmol), C1(0.66g, 2.00mmol) and C4(2.05g, 6.00mmol) were mixed with NMP (50.3g) and reacted at 50 ℃ for 3 hours, then D1(1.82g, 9.4mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 755mPa · s.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.21g) and pyridine (1.00g) were added as an imidization catalyst to react at 80 ℃ for 3 hours. The reaction solution was poured into methanol (230ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (9). The imidization ratio of this polyimide was 71.0%.

[ Synthesis example 10]

D2(2.50g, 10.0mmol), A1(1.99g, 8.00mmol), B3(1.51g, 2.00mmol) and C4(3.41g, 10.0mmol) were mixed with NMP (35.8g) and γ BL (9.0g) and reacted at 50 ℃ for 3 hours, then D1(1.76g, 9.00mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution (10A) having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 797 mPas.

Further, NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.59g) and pyridine (1.11g) were added as an imidization catalyst to react at 80 ℃ for 3 hours. The reaction solution was poured into methanol (232ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (10). The imidization ratio of the polyimide was 75.2%.

[ Synthesis example 11]

D1(2.47g, 12.6mmol), A1(1.00g, 4.00mmol), B3(1.51g, 2.00mmol) and C5(2.78g, 14.0mmol) were mixed with NMP (31.0g) and γ BL (7.7g) and reacted at room temperature for 1 hour, then D3(1.92g, 6.00mmol) was added and reacted at room temperature for 5 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 1129 mPas.

[ Synthesis example 12]

D2(2.50g, 10.0mmol), A7(3.49g, 14.0mmol) and B1(2.28g, 6.00mmol) were mixed with NMP (39.8g) and reacted at 50 ℃ for 3 hours, then D1(1.69g, 8.60mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid concentration of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 1023 mPas. NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.99g) and pyridine (1.24g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (234ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (12). The imidization ratio of this polyimide was 54.3%.

[ Synthesis example 13]

A3(3.49g, 14.0mmol), B1(2.28g, 6.00mmol) and D4(4.47g, 19.94mmol) were mixed with NMP (41.0g) and reacted at 60 ℃ for 6 hours to obtain a polyamic acid solution having a resin solid content of 20% by mass. The viscosity of the polyamic acid solution was measured, and found to be 410 mPas. NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.98 g) and pyridine (1.23g) were added as an imidization catalyst to react at 80 ℃ for 3 hours. The reaction solution was poured into methanol (334ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (13). The imidization ratio of this polyimide was 60.0%.

[ comparative Synthesis example 1]

D2(2.50g, 10.0mmol), B1(2.28g, 6.00mmol) and C2(2.13g, 14.0mmol) were mixed with NMP (35.5g) and reacted at 50 ℃ for 3 hours, then D1(1.95g, 9.96mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 768 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (4.60g) and pyridine (1.43g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (237ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (R1). The imidization ratio of this polyimide was 53.1%.

[ comparative Synthesis example 2]

D2(2.50g, 10.0mmol), B3(3.79g, 5.00mmol), C1(0.66g, 2.00mmol) and C4(4.44g, 13.0mmol) were mixed with NMP (53.0g) and reacted at 50 ℃ for 3 hours, then D1(1.87g, 9.52mmol) was added and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 710 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.06g) and pyridine (0.95g) were added as an imidization catalyst to react at 80 ℃ for 3 hours. The reaction solution was poured into methanol (237ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (R2). The imidization ratio of the polyimide was 75.6%.

[ comparative Synthesis example 3]

D2(2.50g, 10.0mmol), B3(3.03g, 4.00mmol), C1(0.66g, 2.00mmol), C3(2.39g, 6.00mmol) and C5(1.59g, 8.00mmol) were mixed with NMP (48.1g) and reacted at 50 ℃ for 3 hours, D1(1.86g, 9.50mmol) was added thereto and reacted at 40 ℃ for 3 hours to obtain a polyamic acid solution having a resin solid content of 20 mass%. The viscosity of the polyamic acid solution was measured, and found to be 651 mPas.

NMP was added to the obtained polyamic acid solution (20.0g) to dilute the solution to 6.5 mass%, and then acetic anhydride (3.37g) and pyridine (1.04g) were added as an imidization catalyst to react at 50 ℃ for 3 hours. The reaction solution was poured into methanol (231ml), and the resulting precipitate was collected by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ℃ to obtain polyimide powder (R3). The imidization ratio of this polyimide was 50.0%.

[ Table 1]

< preparation of liquid Crystal Aligning agent >

Examples of the preparation of the liquid crystal aligning agent are described in examples and comparative examples. The liquid crystal display elements were produced and evaluated in various ways using the liquid crystal aligning agents obtained in examples and comparative examples.

[ example 1]

NMP (27.0g) was added to the polyimide powder (1) (3.00g) obtained in Synthesis example 1, and the mixture was stirred at 70 ℃ for 24 hours to dissolve the powder. BCS (20.0g) was added to the solution to obtain liquid crystal aligning agent (V-1) of example 1.

[ example 2] to [ example 9]

Liquid crystal alignment agents (V-2) to (V-9) of examples 2 to 9 were obtained in the same manner as in example 1 except that the polyimide powders (2) to (9) were used instead of the polyimide powder (1).

[ example 10]

NMP (27.0g) was added to the polyimide powder (10) (3.00g) obtained in Synthesis example 10, and the mixture was stirred at 70 ℃ for 24 hours to dissolve the powder. BCS (20.0g) was added to the solution to obtain a liquid crystal aligning agent (V-10). The liquid crystal aligning agent (V-10) (5.00g) was mixed with the liquid crystal aligning agent (R-V2) (5.00g) obtained in comparative example 2 to obtain liquid crystal aligning agent (B-10) of example 10.

[ example 11]

NMP (15.0g) and BCS (20.0g) were added to the polyamic acid solution (10A) (15.0g) obtained in Synthesis example 10 to obtain a liquid crystal aligning agent (V-10A). 5.00g of this liquid crystal aligning agent (V-10A) was mixed with 5.00g of the liquid crystal aligning agent (R-V2) obtained in comparative example 2 to obtain a liquid crystal aligning agent (B-11) of example 11.

[ example 12]

NMP (15.0g) and BCS (20.0g) were added to polyamic acid solution (11A) (15.0g) obtained in Synthesis example 11 to obtain liquid crystal alignment agent (V-11A). 5.00g of this liquid crystal aligning agent (V-11A) was mixed with 5.00g of the liquid crystal aligning agent (R-V3) obtained in comparative example 3 to obtain a liquid crystal aligning agent (B-12) of example 12.

It was confirmed that the liquid crystal aligning agents (V-1) to (V-9) and (B-10) to (B-12) obtained as described above were homogeneous solutions without any abnormality such as cloudiness and precipitation.

Using the obtained liquid crystal aligning agents (V-1) to (V-9), (B-10) to (B-12) and (V-13) to (V-14) described later, liquid crystal display devices were produced, and the vertical alignment properties, the pretilt angles, the voltage holding ratios, and the image sticking characteristics were evaluated.

Examples 13 to 14

Liquid crystal alignment agents (V-13) to (V-14) were obtained in the same manner as in example 1, except that the polyimide powders (12) to (13) were used instead of the polyimide powder (1). It was confirmed that the liquid crystal aligning agent was a uniform solution without any abnormality such as turbidity and precipitation.

Comparative example 1

NMP (27.0g) and BCS (20.0g) were added to the polyimide powder (R1) (3.00g) obtained in comparative Synthesis example 1, and the mixture was stirred at 70 ℃ for 24 hours to obtain a liquid crystal aligning agent (R-V1).

Comparative example 2

A liquid crystal aligning agent (R-V2) was obtained in the same manner as in comparative example 1, except that the polyimide powder (R2) was used in place of the polyimide powder (R1) obtained in comparative synthetic example 1.

Comparative example 3

A liquid crystal aligning agent (R-V3) was obtained in the same manner as in comparative example 1, except that the polyimide powder (R3) was used in place of the polyimide powder (R1) obtained in comparative synthetic example 1.

It was confirmed that the liquid crystal aligning agents (R-V1) to (R-V3) obtained as described above were homogeneous solutions without any abnormality such as clouding and precipitation. Using the obtained liquid crystal aligning agents (R-V1) to (R-V2), production of liquid crystal display elements, evaluation of vertical alignment properties, evaluation of pretilt angles, evaluation of voltage holding ratios, and evaluation of residual image characteristics were carried out.

< preparation of liquid Crystal display device for measuring Voltage holding ratio and residual DC Voltage >

The liquid crystal aligning agents (V-1) to (V-9), (B-10) to (B-12) and (V-13) to (V-14) obtained in the examples and the liquid crystal aligning agents (R-V1) to (R-V2) obtained in the comparative examples were subjected to pressure filtration using a membrane filter having a pore size of 1 μm. The obtained solution was spin-coated on an ITO surface of a 40mm X30 mm glass substrate with an ITO electrode (longitudinal: 40mm, lateral: 30mm, thickness: 1.1mm) cleaned with pure water and IPA (isopropyl alcohol), heat-treated on a hot plate at 70 ℃ for 90 seconds, and heat-treated in a thermal cycle type cleaning oven at 230 ℃ for 30 minutes, to obtain an ITO substrate with a liquid crystal alignment film having a film thickness of 100 nm. 2 pieces of the obtained ITO substrates with liquid crystal alignment films were prepared, and a bead spacer (manufactured by Nikkaido catalytic chemical Co., Ltd., Firmized ball, SW-D1) having a diameter of 4 μm was applied to the liquid crystal alignment film surface of one of the substrates.

Next, a sealant (XN-1500T, manufactured by Mitsui chemical Co., Ltd.) was applied to the periphery. Next, the other substrate was bonded to the substrate with the surface on the side where the liquid crystal alignment film was formed being the inner side, and then the sealant was cured to prepare an empty cell. Liquid crystal MLC-3023 (trade name, manufactured by Merck) was injected into the empty cell by a reduced pressure injection method to produce a liquid crystal cell. Irradiating the liquid crystal cell with a DC voltage of 15V from the outside of the liquid crystal cell to a voltage of 10J/cm²UV (1st-UV) emitted from a high-pressure mercury lamp passed through a cut-off filter of 325nm or less.

Thereafter, the liquid crystal cell was irradiated with a fluorescent UV lamp (FLR40SUV32/A-1) for 30 minutes (2nd-UV) without applying a voltage thereto, to inactivate the unreacted polymerizable compound present in the liquid crystal cell. In the measurement of the ultraviolet irradiation amount, a light receiver of UV-35 was connected to UV-M03A manufactured by ORC corporation.

< production of liquid Crystal display element for estimating Pre-Tilt Angle and residual image >

The liquid crystal aligning agents (V-1) to (V-9), (B-10) to (B-12) and (V-13) to (V-14) obtained in the examples and the liquid crystal aligning agents (R-V1) to (R-V2) obtained in the comparative examples were subjected to pressure filtration using a membrane filter having a pore size of 1 μm. The obtained solution was spin-coated on the ITO surface of an ITO electrode substrate (vertical: 35mm, horizontal: 30mm, thickness: 0.7mm) on which an ITO electrode pattern having a pixel size of 200. mu. m.times.600. mu.m and a line/space of 3 μm was formed and a glass substrate (vertical: 35mm, horizontal: 30mm, thickness: 0.7mm) with an ITO electrode on which a spacer (photo spacer) having a height of 3.2 μm was patterned, and the ITO substrate with a liquid crystal alignment film having a film thickness of 100nm was obtained by heat-treating the ITO surface on a hot plate at 70 ℃ for 90 seconds and by a heat-circulation-type cleaning oven at 230 ℃ for 30 minutes. The ITO electrode substrate 4 on which the ITO electrode pattern is formed is equally divided into a staggered grid (checkered) pattern, and 4 regions can be driven individually.

Next, a sealant (XN-1500T, manufactured by Mitsui chemical Co., Ltd.) was applied to the periphery. Next, the other substrate was bonded to the substrate with the surface on the side where the liquid crystal alignment film was formed facing the inside, and then the sealant was cured to produce an empty cell. Liquid crystal MLC-3023 (trade name, manufactured by Merck) was injected into the empty cell by a reduced pressure injection method to produce a liquid crystal cell. Irradiating the liquid crystal cell with a DC voltage of 15V from the outside of the liquid crystal cell to a voltage of 10J/cm²UV (1st-UV) emitted from a high-pressure mercury lamp passed through a cut-off filter of 325nm or less.

Thereafter, the liquid crystal cell was irradiated with a fluorescent UV lamp (FLR40SUV32/A-1) for 30 minutes (2nd-UV) without applying a voltage thereto, to inactivate the unreacted polymerizable compound present in the liquid crystal cell. In the measurement of the amount of ultraviolet irradiation, a light receiver of UV-35 was connected to UV-M03A manufactured by ORC.

< evaluation >

(vertical orientation)

The liquid crystal alignment of the liquid crystal display element was observed with a polarizing microscope (ECLIPSE E600WPOL) (manufactured by nikon) to confirm whether the liquid crystal was vertically aligned. Specifically, when defects due to the flow of the liquid crystal and bright spots due to alignment defects were not observed, the evaluation was good. The evaluation results are shown in table 2.

(Voltage holding ratio)

The voltage holding ratio (%) of the liquid crystal display device for voltage holding ratio evaluation prepared above was measured at 1667 milliseconds after applying a voltage of 1V at intervals of 1667 milliseconds with an application time of 60 microseconds. VHR-1 from TOYO Corporation was used as the measuring device. The evaluation results are shown in table 2.

(pretilt angle)

The pretilt angle evaluation liquid crystal display element prepared as described above was measured using an LCD analyzer (LCA-LUV 42A manufactured by MEIRYO techinica CORPORATION) without defects caused by the flow of liquid crystal. The evaluation results are shown in table 2.

(ghost characteristic)

Using the liquid crystal display element for afterimage evaluation thus produced, an alternating voltage of 60Hz and 20Vp-p was applied to 2 diagonal regions of the 4 pixel regions, and the element was driven at 23 ℃ for 168 hours. Thereafter, all 4 pixel regions were driven with an alternating voltage of 5Vp-p, and the luminance difference of the pixels was visually observed. A state in which little luminance difference was observed was evaluated as good. In the table, good is indicated by ∘, and particularly good is indicated by circulant. The evaluation results are shown in table 2.

(residual DC Voltage)

The liquid crystal display device for evaluation of voltage holding ratio manufactured as described above was applied with a rectangular wave of 30Hz and 7.8Vpp to which 2V direct current was superimposed at 23 ℃ for 100 hours, and the direct current voltage was cut off, and the voltage remaining in the liquid crystal cell after 1 hour (residual DC voltage) was obtained by a flicker elimination method. This value is an index of afterimage due to DC accumulation, and when the value is about 50mV or less, it is judged that the afterimage characteristic is excellent.

[ Table 2]

Claims

1. A liquid crystal aligning agent comprising a polyimide precursor obtained from a diamine component comprising a diamine having a structure represented by the following formula (1) and at least 1 diamine having a side chain structure selected from the group consisting of the following formulae [ S1] to [ S3] and a tetracarboxylic acid component and/or a polyimide polymer which is an imide compound of the polyimide precursor,

in the formula (1), R₁Represents hydrogen, an alkyl group or fluoroalkyl group having 1 to 5 carbon atoms, a t-butoxycarbonyl group or a 1-valent organic group, represents a site bonded to other groups, and any hydrogen atom forming a benzene ring is optionally substituted by the 1-valent organic group,

formula [ S1]In, X¹And X²Each independently represents a single bond, - (CH)₂)_a-、-CONH-、-NHCO-、-CON(CH₃) -, -O-, -COO-, -OCO-or- ((CH)₂)_a1-A₁)_m1A is an integer of 1 to 15, wherein a1 are each independently an integer of 1 to 15, A₁Each independently represents an oxygen atom or-COO-, m₁Is 1 to 2, G¹And G²Independently represent a 2-valent cyclic group selected from a 2-valent aromatic group having 6 to 12 carbon atoms or a 2-valent alicyclic group having 3 to 8 carbon atoms, any hydrogen atom on the cyclic group is optionally substituted by at least 1 selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms or a fluorine atom, m and n are each independently an integer of 0 to 3, the sum of m and n is 1 to 4, R is 1 to 4¹Represents 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 to form R¹Optionally substituted with fluorine,

-X³-R² [S2]

formula [ S2]In, X³Represents a single bond, -CONH-, -NHCO-, -CON(CH₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-, R²Represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms to form R²Optionally substituted with fluorine,

-X⁴-R³ [S3]

formula [ S3]In, X⁴represents-CONH-, -NHCO-, -O-, -COO-or-OCO-, R³Represents a structure having a steroid skeleton.

2. The liquid crystal aligning agent according to claim 1, wherein the diamine having the structure of the formula (1) has a structure of the following formula (1-1),

in the formula (1-1), R₁As in the case of the formula (1), represents a site bonded to other groups, and any hydrogen atom forming a benzene ring is optionally substituted with a 1-valent organic group.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine having the structure of the formula (1) has a structure of the following formula (1-4),

in the formula (1-4), R₁2Q's as in the case of the above formula (1)₂Each independently represents a single bond or a 2-valent organic group, and any hydrogen atom forming a benzene ring is optionally substituted with a 1-valent organic group.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine component comprises a diamine having a side chain structure represented by the formula [ S1 ].

5. The liquid crystal aligning agent according to claim 1 or 2, wherein the side chain structure represented by the formula [ S1] is at least 1 selected from the group consisting of the following formulas [ S1-x1] to [ S1-x7],

formula [ S1-x1]]～[S1-x7]In, R¹Represents an alkyl group having 1 to 20 carbon atoms, X^pIs represented by- (CH)₂)_a-、-CONH-、-NHCO-、-CON(CH₃)-、-NH-、-O-、-CH₂O-, -COO-or-OCO-, a is an integer of 1 to 15, A₁Represents an oxygen atom or-COO-, wherein the bond with the "+" is connected to (CH)₂)_a2Bonding of A₂Represents an oxygen atom or-COO-, wherein the bond with the bond is₂)_a2Bonding, a3 is an integer of 0 or 1, a1 and a2 are each independently an integer of 2-10, and Cy represents 1, 4-cyclohexylene or 1, 4-phenylene.

6. The liquid crystal aligning agent according to claim 1 or 2, which is represented by the formula [ S2]]In the diamines of the side chain structure shown, X³is-CONH-, -NHCO-, -O-, -CH₂O-, -COO-or-OCO-, R²Is C3-20 alkyl or C2-20 alkoxyalkyl.

7. The liquid crystal aligning agent according to claim 1 or 2, wherein the side chain structure represented by the formula [ S3] has a structure represented by the following formula [ S3-x ],

in the formula [ S3-X ], X represents the formula [ X1] or the formula [ X2], Col represents at least 1 selected from the group consisting of the formulae [ Col1] to [ Col3], G represents the formulae [ G1] to [ G4], and in these formulae, X represents a bonding position.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine component contains at least 1 kind of diamine selected from the group consisting of diamines represented by the following formulae [1] and [2],

formula [1]Wherein X represents a single bond, -O-, -C (CH)₃)₂-、-NH-、-CO-、-(CH₂)_m-、-SO₂-or a 2-valent organic group formed from any combination thereof, m is an integer of 1 to 8, and 2Y' S each independently represent a group selected from the formula [ S1]]～[S3]At least 1 of the side chain structures shown.

9. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal display element comprising a liquid crystal alignment film obtained from the liquid crystal alignment film according to claim 9.