KR20200058281A - Liquid crystal aligning agents for forming liquid crystal alignment films, liquid crystal alignment films and liquid crystal display devices using the same - Google Patents

Abstract

The present invention relates to a liquid crystal aligning agent containing a polymer and a solvent which are reaction products from a tetracarboxylicdianhydride and a diamine, wherein the solvent contains at least one specific poor solvent (A) selected from the group of compounds represented by chemical formula (1). The liquid crystal aligning agent according to the present invention may have excellent wet diffusivity and suppress stain of coating when printing a coating for forming a liquid crystal alignment film in inkjet printing or flexo printing, and particularly, damage with respect to a flexo printing plate is reduced (difficult to swell) in the flexo printing, wherein R1 is isopropyl, isobutylor t-butyl, and, R2 isalkylene of carbon number 2-4.

Description

A liquid crystal aligning agent for forming a liquid crystal alignment film, a liquid crystal alignment film and a liquid crystal display device using the same TECHNICAL FIELD

The present invention relates to a liquid crystal aligning agent containing a polyamic acid or a derivative thereof and a specific solvent, a liquid crystal aligning film formed using the liquid crystal aligning agent, or a liquid crystal display device having the liquid crystal aligning film.

Various display devices, such as computer monitors, liquid crystal TVs, video camera viewfinders, and projection displays, or optoelectronics-related devices such as optical printer heads, optical Fourier converters, and light bulbs, are commercially available liquid crystals As the display element, a display element using nematic liquid crystal is mainstream. As a display method of a nematic liquid crystal display device, a TN (Twisted Nematic) mode and a STN (Super Twisted Nematic) mode are well known. Recently, one of the problems of these modes is a TN type liquid crystal display device using an optical compensation film to improve the narrowness of the viewing angle, a multi-domain vertical alignment (MVA) mode using the technology of vertical alignment and projection structure, or a transverse electric field IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode, and the like have been proposed and put into practical use.

Technological development of liquid crystal display devices has been achieved not only by improving their driving methods or device structures, but also by improving the structural members used in the devices. Among the components used in the liquid crystal display element, in particular, the liquid crystal alignment film is one of the important materials related to display quality, and it is becoming important to improve the performance of the alignment film as the quality of the liquid crystal display element increases.

The liquid crystal aligning film is formed from a liquid crystal aligning agent. Currently, a liquid crystal aligning agent mainly used is a solution (varnish) in which a polymer such as polyamic acid, polyamic acid ester or polyimide is dissolved in a solvent. Examples of the solvent include good solvents such as N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) or γ-butyrolactone (hereinafter sometimes abbreviated as GBL), which has excellent polymer solubility. , It is possible to use a poor solvent such as butyl cellosolve (hereinafter sometimes abbreviated as BC), which has low solubility in the polymer but can increase the coating property of the liquid crystal aligning agent. After this solution is applied to a substrate, it is formed by means such as heating to form a polyimide-based liquid crystal alignment film. After film forming, if necessary, an alignment treatment suitable for the above-described display mode is performed.

Industrially, a rubbing method that is simple and capable of high-speed processing of a large area is widely used as an orientation treatment method. The rubbing method is a process of rubbing the surface of the liquid crystal aligning film in one direction using a cloth woven with fibers such as nylon, rayon, and polyester, whereby it becomes possible to obtain uniform alignment of liquid crystal molecules. However, display defects in the liquid crystal display element due to oscillation in the rubbing method or generation of static electricity have been problematic in the past. Although the alignment treatment method by rubbing is still being used in the manufacturing process of a liquid crystal display element, the development of the alignment treatment method which replaces it has been actively performed in recent years.

What is attracting attention as an alignment treatment method instead of the rubbing method is a photo-alignment treatment method in which alignment treatment is performed by irradiating light. In the photo-alignment treatment method, many orientation mechanisms such as photolysis, photoisomerization, photodimerization, and photocrosslinking have been proposed (see, for example, Non-Patent Documents 1, 2, and 2). The photo-alignment method has a higher degree of uniformity of orientation than the rubbing method, and is a non-contact orientation treatment method, so that the film is not scratched and the cause of occurrence of display defects in liquid crystal display elements such as oscillation and static electricity can be reduced. There is an advantage.

On the other hand, as a method of applying a coating film for forming a liquid crystal alignment film to a substrate, spin coating, inkjet printing, flexo printing, and the like are known. Among them, the mainstream are inkjet printing and flexo printing.

In inkjet printing, when the varnish is discharged as water droplets on a substrate and a coating film is formed, stains (stripes) may occur in the surface along the scanning direction of the outlet (nozzle). The causes of this streak stain are (1) water droplets are not sufficiently wet and diffuse to the substrate, (2) the leveling property of the ejected water droplets is poor, and unevenly solute components (solid content) precipitate, (3) wettability It is considered that the drying of this good solvent is quick, and the solution applied during drying degenerates (for example, see Patent Document 3).

In order to solve this problem, in addition to 1-butoxy-2-propanol, butyl cellosolve, diethylene glycol ethyl methyl ether, etc., an example in which diisobutyl ketone is used in combination is disclosed (for example, Patent Document 4). , See 5.). However, with the improvement of the quality of the liquid crystal display element, further improvement is required.

Moreover, in flexographic printing, when a liquid crystal aligning agent is transferred from a flexographic printing plate to a substrate to form a coating film, unevenness due to leveling properties may occur. With the high-precision display, it is desired to form a liquid crystal alignment film having a more uniform film thickness. In order to increase the leveling property, it is effective to use a solvent that improves the wet diffusion property to the flexographic printing plate and the substrate and imparts low surface tension (see Patent Document 6). On the other hand, when a solvent that is easy to swell the flexographic printing plate is used, the flexographic printing plate swells during repeated printing, and the linearity of the end of the coated film transferred from the deformation of the plate due to swelling is inhibited, and the leveling property deteriorates A decrease in printability, such as generation of stains, is concerned.

1-butoxy-2-propanol, diethylene glycol ethyl methyl ether, and the like are known as solvents that impart low surface tension, but these solvents are easy to swell the flexographic printing plate, and the printability as described above to be used for flexographic printing. There is a fear of exacerbation. There is a need for a solvent that imparts low surface tension, improves the leveling properties of the coating film, and is difficult to swell the flexographic printing plate.

Japanese Patent Application Publication No. Hei 9-297313 Japanese Patent Application Publication No. Hei 10-251646 Japanese Patent Application Publication No. 2009-063797 International Publication No. 2009/107406 International Publication No. 2016/080458 Japanese Patent Application Publication No. Hei 7-287236

 LCD, Vol. 3, No. 4, page 262, 1999

An object of the present invention is to print a coating film for forming a liquid crystal alignment film in inkjet printing or flexographic printing, which has good wet diffusivity and can suppress unevenness of the coating film, and is particularly useful for flexographic printing in flexographic printing. It is to provide a liquid crystal aligning agent with little damage (difficult to swell). Moreover, it is providing the liquid crystal aligning film formed using the said liquid crystal aligning agent, or the liquid crystal display element which has the liquid crystal aligning film.

The present inventors have a liquid crystal aligning agent containing at least one specific poor solvent (A) and a polymer selected from the group of compounds represented by formula (1), which have good wet diffusivity, and can suppress staining of the coating film. It was found that it is difficult to swell the flexographic printing plate in flexographic printing. In addition, it was found that the formed liquid crystal alignment film had fewer stains and a more uniform film thickness, thereby completing the present invention. The present invention consists of the following.

[1] A liquid crystal aligning agent containing a polymer and a solvent which are reaction products from tetracarboxylic dianhydride and diamine;

A liquid crystal aligning agent containing at least one specific poor solvent (A), wherein the solvent is selected from the group of compounds represented by formula (1);

Wherein R ¹ is isopropyl, isobutyl or t-butyl; And,

R ² is alkylene having 2 to 4 carbons.

[2] The liquid crystal aligning agent according to [1], in which the specific poor solvent (A) is a compound represented by formula (1-1).

[3] Among the solvents, as a good solvent, N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone The liquid crystal aligning agent as described in [1] or [2] containing at least one selected from the group.

[4] As a poor solvent other than the specific poor solvent (A), butyl cellosolve, 1-butoxy-2-propanol, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, The liquid crystal aligning agent in any one of [1]-[3] containing at least one selected from the group which consists of diisobutyl ketone and 4-methyl-2-pentanol.

[5] The liquid crystal aligning agent according to any one of [1] to [4], wherein the proportion of the specific poor solvent (A) is 0.1 to 60% by weight relative to the total solvent weight.

[6] The liquid crystal aligning agent according to any one of [1] to [5], wherein the ratio of the good solvent is 20 to 89% by weight relative to the total solvent weight when a solvent other than the specific poor solvent (A) is included.

[7] A method for forming a liquid crystal alignment film comprising a step of applying the liquid crystal aligning agent according to any one of [1] to [6] by inkjet printing or flexographic printing.

[8] A method for forming a liquid crystal alignment film comprising a step of applying, drying, and firing the liquid crystal aligning agent according to any one of [1] to [6].

[9] A method for manufacturing a liquid crystal display device comprising the step of forming the liquid crystal alignment film according to [7] or [8].

According to the present invention, it is possible to provide a liquid crystal aligning agent having good wet diffusivity and excellent printability. And this liquid crystal aligning agent can suppress generation | occurrence | production of the stain of a coating film, and can form a liquid crystal aligning film with a more uniform film thickness.

The subject of the present invention is a liquid crystal aligning agent containing a polymer and a solvent which are reaction products from tetracarboxylic dianhydride and diamine, wherein the solvent is at least one specific poor solvent selected from the group of compounds represented by formula (1) It is a liquid crystal aligning agent containing (A).

<Solvent used in the present invention>

The solvent used as the liquid crystal aligning agent of the present invention is three groups of poor solvents (hereinafter sometimes referred to as "other poor solvents") other than specific poor solvents (A), good solvents, and specific poor solvents (A). It is divided into.

<Specific poor solvent (A)>

The specific poor solvent (A) of the present invention is a useful solvent that is not only good in wet diffusivity but also difficult to swell the flexographic printing plate used for flexographic printing, and can be used as a liquid crystal aligning agent. The specific poor solvent (A) is at least one selected from the group of compounds represented by the following formula (1).

In the formula, R ¹ is isopropyl, isobutyl or t-butyl, and R ² is alkylene having 2 to 4 carbons.

As a specific example of the compound represented by Formula (1), from the viewpoint of ease of availability, wet diffusivity and boiling point, a solvent represented by Formula (1-1), Formula (1-2) or Formula (1-3) is preferable. , The solvent represented by Formula (1-1) is more preferable. In addition, in inkjet printing and flexographic printing, wettability as well as boiling point are important. In the coating film formed by inkjet printing and flexographic printing, if a specific poor solvent (A) volatilizes before the drying process, there are fewer solvents that impart low surface tension, and the wet diffusibility deteriorates and the printability deteriorates. . Conversely, if the good solvent volatilizes first, there is a fear that the polymer may precipitate. In flexo printing, there is the same concern not only on the coating film but also on the flexo printing plate. The boiling point of the solvent represented by Formula (1-1), Formula (1-2) or Formula (1-3) is a boiling point suitable for obtaining good printability in combination with a good solvent such as NMP or GBL. Among these, solvents represented by formulas (1-1) and (1-2) are particularly suitable.

<Two-way agent>

The good solvent is selected from the group of polar organic solvents having good solubility in the polymer forming the liquid crystal alignment film.

Specific examples of such polar organic solvents are N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylimidazolidinone, N-methylcaprolactam, N-methylpropionamide, N, N- Lactones such as dimethylacetamide, dimethylsulfoxide, N, N-dimethylformamide, N, N-diethylformamide, diethylacetamide and γ-butyrolactone.

Among these solvents, solvents showing particularly good solubility are N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, and N-ethyl-2-pyrrolidone. .

<Other poor solvents>

The liquid crystal aligning agent of this invention may contain other poor solvents as needed. Other poor solvents are characterized by relatively small surface energy of about 30 mN / m and wettability.

Examples of other poor solvents include butyl cellosolve (ethylene glycol monobutyl ether), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monobutyl ether. , Propylene glycol monopropyl ether, 1-butoxy-2-propanol, ethyl lactate, methyl lactate, propyl lactate,

Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol ethyl propyl ether, diethylene glycol butyl methyl ether, diethylene glycol propyl methyl Ether, diethylene glycol butyl ethyl ether, propylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate , Propylene glycol monomethyl ether propionate, dipropylene glycol monomethyl ether, diisobutyl ketone, and 4-methyl-2-pentanol.

Among the entire solvents in the liquid crystal aligning agent of the present invention, as the amount of the specific poor solvent (A) increases, the effect of the present invention, i.e., the effect of increasing the wettability of the solution, can be expected. It is preferable to include a agent, and it is important that the balance (constitution ratio) of the specific poor solvent (A) and the good solvent is good. Thereby, a liquid crystal aligning agent excellent in coatability can be obtained. Since these three types of solvents of a specific poor solvent (A), a good solvent, and other poor solvents each have different characteristics, it is important to have the constitution ratios described below.

The ratio of the specific poor solvent (A) to the total solvent weight is preferably used in a ratio of 0.1 to 60% by weight relative to the total solvent weight, more preferably 5 to 50% by weight, to obtain good wet diffusibility, 10 to 45 weight% is more preferable.

The good solvent is preferably used in a ratio of 20% by weight or more with respect to the total weight of the solvent to prevent precipitation of the polymer in solution, clogging of the nozzle or head of the inkjet device, and precipitation of the polymer on the flexo printing plate during flexo printing. . On the other hand, since it is necessary to use a certain amount of poor solvent in order to maintain good printability, the good solvent is preferably used at a ratio of 89% by weight or less based on the total solvent weight. The ratio of the good solvent to the total solvent weight is preferably 20 to 89% by weight, more preferably 30 to 84% by weight, and still more preferably 45 to 75% by weight.

Other poor solvents are preferably used in a ratio of 5 to 40% by weight relative to the total solvent weight to ensure wettability.

When a specific poor solvent (A) and other poor solvents are used together, the total weight percentage of the specific poor solvent (A) and other poor solvents is preferably 5 to 50% of the total solvent weight, and 10 to 40% More preferably, 25 to 35% is more preferable.

Among other poor solvents, the surface energy is less than 30 mN / m, and a solvent having an effect of improving wettability to the substrate, for example, butyl cellosolve, 1-butoxy-2-propanol, diethylene glycol diethyl ether , When diethylene glycol ethyl methyl ether and diethylene glycol butyl methyl ether are used in combination with a specific poor solvent (A), the ratio to the total solvent weight of these other poor solvents is preferably 0.1 to 50% by weight, 3-40 weight% is more preferable, and 3-25 weight% is more preferable.

In addition, among other poor solvents, the surface energy is further lowered, the wet diffusion to the substrate is improved, and as a useful solvent for suppressing the occurrence of streak unevenness in inkjet printing, for example, diisobutyl ketone, 4-methyl 2-pentanol and dipentyl ether. In the case of inkjet printing use, when these other poor solvents are used in combination, an alignment film having better printability is obtained. When these other poor solvents are used in combination with a specific poor solvent (A), it is preferable to use these other poor solvents in a ratio of 0.1% by weight or more based on the total solvent weight. On the other hand, since it is necessary to use a certain amount of good solvent in order to prevent the precipitation of the polymer, the nozzle of the inkjet device, or the clogging of the head, these other poor solvents are used in a ratio of 20% by weight or less based on the total solvent weight. It is desirable to do. The ratio of these other poor solvents to the total solvent weight is preferably 0.1 to 20% by weight, more preferably 0.1 to 18% by weight, and even more preferably 0.1 to 15% by weight.

<Polymer of the present invention>

The polymer of the present invention is a derivative of polyamic acid and polyamic acid which are reaction products of at least one selected from tetracarboxylic dianhydride and its derivatives and diamine. The derivative of the tetracarboxylic dianhydride is tetracarboxylic acid diester or tetracarboxylic acid diester dichloride. A derivative of a polyamic acid is a component that dissolves in a solvent when a liquid crystal aligning agent described later containing a solvent is used, and a component capable of forming a liquid crystal aligning film containing polyimide as a main component when the liquid crystal aligning agent is a liquid crystal aligning film. to be. Examples of the derivative of the polyamic acid include, for example, soluble polyimide, polyamic acid ester and polyamic acid amide, and more specifically 1) polyimide in which all amino and carboxyl groups of the polyamic acid are dehydrated and cyclized, 2 ) Partially polyimide partially reacted with dehydration, 3) Polyamic acid ester in which the carboxyl of polyamic acid is converted to ester, 4) Substitute part of the acid dianhydride contained in the tetracarboxylic dianhydride compound with organic dicarboxylic acid And a polyamideimide obtained by subjecting and reacting to a polyamic acid-polyamide copolymer obtained by dehydrating and ring-closing a part or all of the polyamic acid-polyamide copolymer. The polyamic acid and its derivatives may be one type of polymer, or two or more types. In addition, the polyamic acid and its derivatives may be a polymer having a structure of a reaction product of tetracarboxylic dianhydride and diamine, and other raw materials may be used for reactions other than the reaction of tetracarboxylic dianhydride and diamine. You may contain a reaction product.

The polyamic acid ester is a method for synthesizing by reacting the above-mentioned polyamic acid with a hydroxyl group-containing compound, a halide or an epoxy group-containing compound, or a tetracarboxylic acid diester or tetracarboxylic acid diester dichloride and diamine derived from an acid dianhydride. It can be synthesized by a method of synthesizing by reacting. The tetracarboxylic acid diester derived from the acid dianhydride can be obtained by, for example, reacting an acid dianhydride with a 2 equivalent alcohol and opening it, and the tetracarboxylic acid diester dichloride is a 2 equivalent chlorinating agent of the tetracarboxylic acid diester (For example, thionyl chloride, etc.). On the other hand, the polyamic acid ester may have only the amic acid ester structure, or may be a partial esterified product in which the amic acid structure and the amic acid ester structure coexist.

Further, when the polyamic acid of the present invention is a polyamic acid derivative, polyimide, the obtained polyamic acid solution is acid anhydride such as acetic anhydride, propionic acid anhydride, and trifluoroacetic anhydride, and triethylamine which is a dehydration cyclization catalyst. It can be obtained by imidizing with a tertiary amine such as pyridine or collidine at a temperature of 20 to 150 ° C. Alternatively, a polyamic acid is precipitated from the obtained polyamic acid solution using a large amount of poor solvent (an alcoholic solvent such as methanol, ethanol, isopropanol or a glycolic solvent), and the precipitated polyamic acid is dissolved in a solvent such as toluene or xylene. With the same dehydrating agent and dehydrating ring-closing catalyst, imidization reaction may be performed at a temperature of 20 to 150 ° C.

In the imidation reaction, the ratio of the dehydrating agent and the dehydrating ring-closure catalyst is preferably 0.1 to 10 (molar ratio). It is preferable that the total amount of both used is 1.5 to 10 times molar with respect to the total molar amount of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid. By adjusting the dehydrating agent of the chemical imidization, the amount of catalyst, the reaction temperature and the reaction time, the degree of imidization can be controlled, and a partial polyimide can be obtained. The obtained polyimide can be used as a liquid crystal aligning agent by separating it from the solvent and re-dissolving in the above-described solvent, or can be used as a liquid crystal aligning agent without being separated from the solvent.

The polyamic acid ester is a method for synthesizing by reacting the above-mentioned polyamic acid with a hydroxyl group-containing compound, a halide, an epoxy group-containing compound or the like, or a tetracarboxylic acid diester or tetracarboxylic acid diester dichloride derived from tetracarboxylic dianhydride It can be synthesized by a method of synthesizing by reacting with diamine. Tetracarboxylic acid diesters derived from tetracarboxylic dianhydride can be obtained, for example, by reacting and opening a tetracarboxylic dianhydride with 2 equivalent alcohol, and tetracarboxylic acid diester dichloride is tetracarboxylic acid diester It can be obtained by reacting an ester with a 2 equivalent chlorinating agent (for example, thionyl chloride). On the other hand, the polyamic acid ester may have only the amic acid ester structure, or may be a partial esterified product in which the amic acid structure and the amic acid ester structure coexist. The liquid crystal aligning agent for photo-alignment of this invention may contain these polyamic acid, polyamic acid ester, and one polyimide obtained by imidizing them, or may contain two or more.

The molecular weight of the polyamic acid or its derivatives of the present invention is preferably 7,000 to 500,000 as a weight average molecular weight (Mw) in terms of polystyrene, and more preferably 10,000 to 200,000. The molecular weight of the polyamic acid or its derivative can be determined by measuring by gel permeation chromatography (GPC).

The presence of polyamic acid or its derivatives of the present invention can be confirmed by analyzing the solid content obtained by precipitation with a large amount of poor solvent by IR and NMR. Alternatively, the monomer used can be confirmed by analyzing the extract with an organic solvent of a decomposition product of the polyamic acid or its derivative by an aqueous solution of strong alkali such as KOH or NaOH by GC, HPLC or GC-MS.

<Tetracarboxylic dianhydride>

The tetracarboxylic dianhydride used to prepare the polyamic acid and its derivatives included in the liquid crystal aligning agent of the present invention will be described. The tetracarboxylic dianhydride used in the present invention can be selected without limitation from known tetracarboxylic dianhydrides. These tetracarboxylic dianhydrides include aromatic systems (including heteroaromatic rings) in which dicarboxylic acid anhydrides are directly bonded to aromatic rings and aliphatic systems in which dicarboxylic acid anhydrides are not directly bonded to aromatic rings (heterocyclic rings). (Including systems). In the tetracarboxylic dianhydride, one compound may be reacted with diamine, or two or more compounds may be mixed to react with diamine. In this specification, "tetracarboxylic dianhydride" not only refers to one compound, but may also include a mixture of two or more compounds in its meaning.

The polyamic acid or derivative thereof of the present invention can be prepared in the same manner as a known polyamic acid or derivative thereof used for forming a polyimide film. The total amount of tetracarboxylic dianhydride to be added is preferably approximately equal to the total number of moles of diamine (a molar ratio of 0.9 to 1.1).

Preferred examples of such tetracarboxylic dianhydride are tetracarboxylic dianhydride represented by formulas (AN-I) to (AN-V) in terms of ease of obtaining raw materials, ease of polymer production, and electrical properties of membranes. Can be heard.

In formulas (AN-I), formulas (AN-IV) and formulas (AN-V), X is independently a single bond or -CH _2- . In formula (AN-II), G is a single bond, alkylene having 1 to 20 carbon atoms, -CO-, -O-, -S-, -SO _2- , -C (CH ₃ ) _2- , or -C (CF ₃ ) _2- . In formulas (AN-II) to (AN-IV), Y is independently one selected from the group of the following trivalent groups, the number of bonds is connected to any carbon, and at least one hydrogen of this group is It may be substituted with methyl, ethyl or phenyl.

In formulas (AN-III) to (AN-V), ring A ¹⁰ is a monocyclic hydrocarbon group having 3 to ¹⁰ carbon atoms or a condensed polycyclic hydrocarbon group having 6 to 30 carbon atoms, and at least one hydrogen of this group is It may be substituted with methyl, ethyl or phenyl, and the number of bonds connected to the ring may be linked to any carbon constituting the ring, and two number of bonds may be linked to the same carbon.

More specifically, the tetracarboxylic dianhydride represented by following formula (AN-1)-formula (AN-16-15) is mentioned.

[Tetracarboxylic acid dianhydride represented by Formula (AN-1)]

In formula (AN-1), G ¹¹ is a single bond, alkylene having 1 to 12 carbons, 1,4-phenylene, or 1,4-cyclohexylene. X ¹¹ is independently a single bond or -CH _2- . G ¹² is independently one of the following trivalent groups.

When G ¹² is> CH-, hydrogen of> CH- may be substituted with -CH ₃ . When G ¹² is> N-, G ¹¹ is not a single bond and -CH _2- , and X ¹¹ is not a single bond. And R ¹¹ is hydrogen or -CH ₃ .

As an example of the tetracarboxylic dianhydride represented by Formula (AN-1), the compound represented by the following formula is mentioned.

In formulas (AN-1-2) and (AN-1-14), m is an integer from 1 to 12.

[Tetracarboxylic acid dianhydride represented by Formula (AN-3)]

In formula (AN-3), ring A ¹¹ is a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-3), the compound represented by the following formula is mentioned.

[Tetracarboxylic acid dianhydride represented by Formula (AN-4)]

In the formula (AN-4), G ¹³ is a single bond,-(CH ₂ ) _m- , -O-, -S-, -C (CH ₃ ) _2- , -SO _2- , -CO-,- C (CF ₃ ) _2- , or a divalent group represented by the following formula (G13-1), m is an integer from 1 to 12. The intermediate ring A ¹¹ is each independently a cyclohexane ring or a benzene ring. G ¹³ may be bonded to any position on the ring A ¹¹ .

In formula (G13-1), G ^13a and G ^13b are each independently a single bond, a divalent group represented by -O- or -NHCO-. As for phenylene, 1,4-phenylene and 1,3-phenylene are preferable.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-4), the compound represented by the following formula is mentioned.

In the formula (AN-4-17), m is an integer from 1 to 12.

[Tetracarboxylic dianhydride represented by formula (AN-5)]

In formula (AN-5), R ¹¹ is independently hydrogen or -CH ₃ . R ¹¹ in which the bonding position is not fixed to the carbon atom constituting the benzene ring indicates that the bonding position in the benzene ring is arbitrary.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-5), the compound represented by the following formula is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-6)]

In formula (AN-6), X ¹¹ is independently a single bond or -CH _2- . X ¹² is -CH _2- , -CH ₂ CH ₂ -or -CH = H-. n is 1 or 2.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-6), the compound represented by the following formula is mentioned.

[Tetracarboxylic dianhydride represented by Formula (AN-7)]

In formula (AN-7), X ¹¹ is a single bond or -CH _2- .

As an example of the tetracarboxylic dianhydride represented by Formula (AN-7), the compound represented by the following formula is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-8)]

In formula (AN-8), X ¹¹ is a single bond or -CH _2- . R ¹² is hydrogen, -CH ₃ , -CH ₂ CH _3, or phenyl, and ring A ¹² is a cyclohexane ring or cyclohexene ring.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-8), the compound represented by the following formula is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-9)]

In formula (AN-9), r is 0 or 1 each independently.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-9), the compound represented by the following formula is mentioned.

[Tetracarboxylic acid dianhydride represented by Formula (AN-10-1) and Formula (AN-10-2)]

[Tetracarboxylic acid dianhydride represented by Formula (AN-11)]

In formula (AN-11), ring A ¹¹ is independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-11), the compound represented by the following formula is mentioned.

[Tetracarboxylic dianhydride represented by formula (AN-12)]

In formula (AN-12), ring A ¹¹ is each independently a cyclohexane ring or a benzene ring.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-12), the compound represented by the following formula is mentioned.

[Tetracarboxylic acid dianhydride represented by Formula (AN-15)]

In formula (AN-15), w is an integer of 1-10.

As an example of the tetracarboxylic dianhydride represented by Formula (AN-15), the compound represented by the following formula is mentioned.

The following compounds are mentioned as tetracarboxylic dianhydride other than the above.

Preferred materials in the above tetracarboxylic dianhydride to improve the properties of the liquid crystal alignment film described later will be described. When emphasizing on improving the alignment of the liquid crystal, compounds represented by formulas (AN-1), (AN-3) and (AN-4) are preferred, and formulas (AN-1-2) and ( The compounds represented by AN-1-13), formulas (AN-3-2), formulas (AN-4-17) and formulas (AN-4-29) are more preferable, and formula (AN-1-2) In this, m = 4 or 8 is preferable, in formula (AN-4-17), m = 4 or 8 is preferable, and m = 8 is more preferable.

When emphasizing on improving the transmittance of the liquid crystal display element, formula (AN-1-1), formula (AN-1-2), formula (AN-3-1), formula (AN-4-17), Expression (AN-4-30), Expression (AN-5-1), Expression (AN-7-2), Expression (AN-10-1), Expression (AN-16-3), Expression (AN-16) -4) and the compound represented by formula (PA-1) are preferred, m = 4 or 8 is preferred in formula (AN-1-2), and m = in formula (AN-4-17). 4 or 8 is preferable, and m = 8 is more preferable.

When emphasizing on improving the voltage retention rate (hereinafter sometimes abbreviated as VHR) of a liquid crystal display element, equations (AN-1-1), equations (AN-1-2), and equations (AN-3- 1), equation (AN-4-17), equation (AN-4-30), equation (AN-7-2), equation (AN-10-1), equation (AN-16-3), equation ( AN-16-4) and the compound represented by formula (PA-1) are preferable, m = 4 or 8 is preferable in formula (AN-1-2), and m in formula (AN-4-17) = 4 or 8 is preferable, and m = 8 is more preferable.

By reducing the volume resistance value of the liquid crystal alignment film, it is effective to improve the relaxation rate of the residual charge (residual DC) in the alignment film as one of the methods for preventing burning. When this objective is emphasized, formula (AN-1-13), formula (AN-3-2), formula (AN-4-21), formula (AN-4-29) and formula (AN-11- The compound represented by 3) is preferable.

<Diamine and dihydrazide>

The diamine and dihydrazide used to prepare the polyamic acid and its derivatives of the present invention will be described. In preparing the polyamic acid of the present invention or a derivative thereof, it can be selected without limitation from known diamines and dihydrazides.

Diamine can be divided into two types according to its structure. That is, when a skeleton connecting two aminos is viewed as a main chain, it is a group branching from the main chain, that is, a diamine having a side chain group and a diamine having no side chain group. In the following description, a diamine having such a side chain group may be referred to as a side chain type diamine. In addition, a diamine having no such side chain group may be referred to as a non-branched diamine. This side chain group is a group having an effect of increasing the pretilt angle. By appropriately separating and using the non-branched diamine and the branched diamine, it is possible to correspond to the pretilt angle required for each. It is preferable to use the side chain type diamine together to the extent that it does not impair the properties of the present invention. In addition, it is preferable to select and use the side chain type diamine and the non-side chain type diamine for the purpose of improving the vertical alignment property, voltage retention, baking property, and alignment property to the liquid crystal.

The well-known diamine and dihydrazide are shown below.

In the formula (DI-1), G ²⁰ is -CH ₂ -or formula (DI-1-a), and when G ²⁰ is -CH _2- , at least one -CH ₂ -is -NH -, -O- may be substituted, m is an integer of 1 to 12, at least one hydrogen of alkylene may be substituted with -OH or -CH ₃ , and G ²⁰ is represented by formula (DI-1-a). In this case m is 0.

In formula (DI-1-a), v is an integer of 1-6.

In formulas (DI-3) and (DI-7), G ²¹ is independently a single bond, -NH-, -NCH _3- , -O-, -S-, -SS-, -SO _2- , -CO-, -COO-, -CONCH _3- , -CONH-, -C (CH ₃ ) _2- , -C (CF ₃ ) ₂ -,-(CH ₂ ) _m- , -O- (CH ₂ ) _m -O-, -N (CH ₃ )-(CH ₂ ) _k -N (CH ₃ )-,-(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C (CF ₃ ) _2- CH ₂ -O-, -O-CO- (CH ₂ ) _m -CO-O-, -CO-O- (CH ₂ ) _m -O-CO-,-(CH ₂ ) _m -NH- (CH ₂ ) _m- , -CO- (CH ₂ ) _k -NH- (CH ₂ ) _k -,-(NH- (CH ₂ ) _m ) _k -NH-, -CO-C ₃ H _6- (NH-C ₃ H ₆ ) _n -CO-, or -S- (CH ₂ ) _m -S-, m is independently an integer from 1 to 12, k is an integer from 1 to 5, and n is 1 or 2.

In formula (DI-4), s is an integer of 0-2 independently.

In the formula (DI-5), G ³³ is independently a single bond, -NH-, -NCH _3- , -O-, -S-, -SS-, -SO _2- , -CO-, -COO- , -CONCH _3- , -CONH-, -C (CH ₃ ) _2- , -C (CF ₃ ) ₂ -,-(CH ₂ ) _m- , -O- (CH ₂ ) _m -O-, -N (CH ₃ )-(CH ₂ ) _k -N (CH ₃ )-,-(OC ₂ H ₄ ) _m -O-, -O-CH ₂ -C (CF ₃ ) ₂ -CH ₂ -O-,- O-CO- (CH ₂ ) _m -CO-O-, -CO-O- (CH ₂ ) _m -O-CO-,-(CH ₂ ) _m -NH- (CH ₂ ) _m- , -CO- (CH ₂ ) _k -NH- (CH ₂ ) _k -,-(NH- (CH ₂ ) _m ) _k -NH-, -CO-C ₃ H _6- (NH-C ₃ H ₆ ) _n -CO- , Or -S- (CH ₂ ) _m -S-, -N (Boc)-(CH ₂ ) _e -N (Boc)-, -NH- (CH ₂ ) _e -N (Boc)-, -N ( Boc)-(CH ₂ ) _e- , a group represented by the following formula (DI-5-a) or the following formula (DI-5-b), m is an integer of 1 to 12 independently, and k is 1 to 5 Is an integer, e is an integer from 2 to 10, and n is 1 or 2.

In (DI-5-a), q is an integer of 0 to 6, R ⁴⁴ is hydrogen, -OH, alkyl having 1 to 6 carbons, or alkoxy having 1 to 6 carbons.

In formulas (DI-6) and (DI-7), G ²² is independently a single bond, -O-, -S-, -CO-, -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , or alkylene having 1 to 10 carbon atoms.

At least one hydrogen of the cyclohexane ring and benzene ring in the formulas (DI-2) to (DI-7) is -F, -Cl, alkylene having 1 to 3 carbon atoms, -OCH ₃ , -OH, -CF ₃ , -CO ₂ H, -CONH ₂ , -NHC ₆ H ₅ , may be substituted with phenyl or benzyl, and in formula (DI-4), at least one hydrogen of the cyclohexane ring and the benzene ring is It may be substituted with one selected from the group of groups represented by (DI-4-a) to (DI-4-i), and in the formula (DI-5), when G ³³ is a single bond, cyclohexane ring and benzene Hydrogen having at least one ring may be substituted with NHBoc or N (Boc) ₂ .

In formulas (DI-4-a) and (DI-4-b), R ²⁰ is independently hydrogen or -CH ₃ . In formulas (DI-4-f) and formulas (DI-4-g), m is an integer from 0 to 12, and Boc is t-butoxycarbonyl.

In the above formula, a group in which the bonding position is not fixed to the carbon atom constituting the ring indicates that the bonding position in the ring is arbitrary. And, the bonding position of -NH ₂ to the cyclohexane ring or benzene ring is any position except for the bonding position of G ²¹ , G ²² or G ³³ .

In formula (DI-11), r is 0 or 1. In formulas (DI-8) to (DI-11), the bonding position of -NH ₂ bonded to the ring is any position.

In the formula (DI-12), R ²¹ and R ²² are independently alkyl or phenyl having 1 to 3 carbons, G ²³ is independently alkylene having 1 to 6 carbons, phenylene or alkyl-substituted phenylene, w is an integer from 1 to 10.

In formula (DI-13), R ²³ is independently alkyl having 1 to 5 carbons, alkoxy having 1 to 5 carbons, or -Cl, p is an integer of 0 to 3 independently, and q is an integer of 0 to 4 to be.

In formula (DI-14), ring B is a monocyclic heterocyclic aromatic group, R ²⁴ is hydrogen, -F, -Cl, alkyl having 1 to 6 carbons, alkoxy, alkenyl, alkynyl, q is independent Is an integer from 0 to 4. In formula (DI-15), ring C is a heterocyclic aromatic group or a heterocyclic aliphatic group. In the formula (DI-16), G ²⁴ is a single bond, alkylene having 2 to 6 carbons or 1,4-phenylene, and r is 0 or 1. And, the group in which the bonding position is not fixed to the carbon atom constituting the ring indicates that the bonding position in the ring is arbitrary. In formulas (DI-13) to (DI-16), the bonding position of -NH ₂ bonded to the ring is any position.

Specific examples of the following formulas (DI-1-1) to (DI-16-1) include diamines having no side chains of the formulas (DI-1) to (DI-16).

The example of the diamine represented by Formula (DI-1) is shown below.

In Formula (DI-1-7) and Formula (DI-1-8), k are each independently an integer of 1-3. In formula (DI-1-9), v is an integer of 1-6.

Examples of diamines represented by formulas (DI-2) to (DI-3) are shown below.

The example of the diamine represented by Formula (DI-4) is shown below.

The example of the diamine represented by Formula (DI-5) is shown below.

In formula (DI-5-1), m is an integer of 1-12.

In Formula (DI-5-12) and Formula (DI-5-13), m is an integer of 1 to 12.

In formula (DI-5-16), v is an integer of 1-6.

In formula (DI-5-30), k is an integer of 1-5.

In formulas (DI-5-35) to (DI-5-37) and formula (DI-5-39), m is an integer from 1 to 12, and formulas (DI-5-38) and formula (DI In -5-39), k is an integer of 1 to 5, and in formula (DI-5-40), n is an integer of 1 or 2.

In formulas (DI-5-42) to (DI-5-44), e is an integer from 2 to 10, and in formula (DI-5-45), R ⁴³ is hydrogen, NHBoc or N (Boc ) ₂ . In formulas (DI-5-42) to (DI-5-45), Boc is t-butoxycarbonyl.

The example of the diamine represented by Formula (DI-6) is shown below.

The example of the diamine represented by Formula (DI-7) is shown below.

In Formula (DI-7-3) and Formula (DI-7-4), m is an integer of 1 to 12, and n is 1 or 2 independently.

The example of the diamine represented by Formula (DI-8) is shown below.

The example of the diamine represented by Formula (DI-9) is shown below.

The example of the diamine represented by Formula (DI-10) is shown below.

The example of the diamine represented by Formula (DI-11) is shown below.

The example of the diamine represented by Formula (DI-12) is shown below.

The example of the diamine represented by Formula (DI-13) is shown below.

The example of the diamine represented by Formula (DI-14) is shown below.

The example of the diamine represented by Formula (DI-15) is shown below.

The example of the diamine represented by Formula (DI-16) is shown below.

Dehydrazide is described. The following formulas (DIH-1) to (DIH-3) are mentioned as dihydrazide having no well-known side chain.

In the formula (DIH-1), G ²⁵ is a single bond, alkylene having 1 to 20 carbons, -CO-, -O-, -S-, -SO _2- , -C (CH ₃ ) _2- , or -C (CF ₃ ) _2- . In the formula (DIH-2), ring D is a cyclohexane ring, a benzene ring or a naphthalene ring, and at least one hydrogen of this group may be substituted with methyl, ethyl or phenyl. In the formula (DIH-3), each ring E is independently a cyclohexane ring or a benzene ring, and at least one hydrogen of this group may be substituted with methyl, ethyl, or phenyl, Y is a single bond, carbon number Alkylene of 1 to 20, -CO-, -O-, -S-, -SO _2- , -C (CH ₃ ) _2- , or -C (CF ₃ ) _2- . In the formulas (DIH-2) and (DIH-3), the bonding position of -CONHNH ₂ that binds to the ring is any position.

Examples of the formulas (DIH-1) to (DIH-3) are shown below.

In formula (DIH-1-2), m is an integer of 1-12.

A diamine suitable for the purpose of increasing the pretilt angle will be described. Examples of diamines having side chain groups suitable for the purpose of increasing the pretilt angle include formulas (DI-31) to (DI-35) and formulas (DI-36-1) to (DI-36-8). .

In the formula (DI-31), G ²⁶ is a single bond, -O-, -COO-, -OCO-, -CO-, -CONH-, -CH ₂ O-, -OCH _2- , -CF ₂ O -, -OCF _2- , or-(CH ₂ ) _{m '} -, and m' is an integer from 1 to 12. Preferred examples of G ²⁶ are single bond, -O-, -COO-, -OCO-, -CH ₂ O- and alkylene having 1 to 3 carbon atoms, particularly preferred examples are single bond, -O-, -COO- , -OCO-, -CH ₂ O-, -CH ₂ -and -CH ₂ CH _2- . R ²⁵ is a group having an alkyl, phenyl, or steroid skeleton having 3 to 30 carbon atoms, or a group represented by the following formula (DI-31-a). In this alkyl, at least one hydrogen may be substituted with -F, and at least one -CH ₂ -may be substituted with -O-, -CH = CH- or -C≡C-. Hydrogen of the phenyl is _{-F, -CH 3, -OCH 3,} -OCH 2 F, -OCHF 2, -OCF 3, or may be substituted by alkyl or alkoxy having a carbon number of 3 to 30 carbon atoms of 3 to 30. Although the bonding position of -NH ₂ bonded to the benzene ring is shown to be an arbitrary position in the ring, the bonding position is preferably meta or para. That is, when the combined position of the group "R ²⁵ -G ^26- " is 1, it is preferable that the 2 combined positions are 3rd and 5th, or 2nd and 5th.

In the formula (DI-31-a), G ²⁷ , G ²⁸ and G ²⁹ are a bonding group, and these are independently a single bond or an alkylene having 1 to 12 carbons, and one or more -CH ₂ -of the alkylene is It may be substituted with -O-, -COO-, -OCO-, -CONH-, -CH = CH-. Ring B ²¹ , ring B ²² , ring B ²³ and ring B ²⁴ are independently 1,4-phenylene, 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2 , 5-diyl, pyridine-2,5-diyl, naphthalene-1,5-diyl, naphthalene-2,7-diyl or anthracene-9,10-diyl, ring B ²¹ , ring B ²² , ring B ²³ and In ring B ²⁴ , at least one hydrogen may be substituted with -F or -CH ₃ , and s, t and u are independently integers of 0 to 2, and their total is 1 to 5, and s, t Alternatively, when u is 2, the two linking groups in each parenthesis may be the same or different, and the two rings may be the same or different. R ²⁶ is hydrogen, -F, -OH, alkoxy, -CN of fluorine-substituted alkyl, of 1 to 30 carbon atoms in the alkyl, of 1 to 30 carbon atoms of 1 to 30 carbon atoms, -OCH ₂ F, -OCHF _2, or -OCF ₃ , And at least one -CH ₂ -of the alkyl having 1 to 30 carbons may be substituted with a divalent group represented by the following formula (DI-31-b).

In the formula (DI-31-b), R ²⁷ and R ²⁸ are independently alkyl having 1 to 3 carbons, and v is an integer from 1 to 6. Preferred examples of R ²⁶ are alkyl having 1 to 30 carbons and alkoxy having 1 to 30 carbons.

In formulas (DI-32) and (DI-33), G ³⁰ is independently a single bond, -CO- or -CH _2- , R ²⁹ is independently hydrogen or -CH ₃ , and R ³⁰ is hydrogen , Alkyl having 1 to 20 carbons, or alkenyl having 2 to 20 carbons. Hydrogen having at least one benzene ring in formula (DI-33) may be substituted with alkyl having 1 to 20 carbons or phenyl. In addition, a group in which the bonding position is not fixed to several carbon atoms constituting the ring indicates that the bonding position in the ring is arbitrary. It is preferable that one of the two groups "-phenylene-G ³⁰ -O-" in formula (DI-32) binds to the 3rd position of the steroid nucleus, and the other to the 6th position of the steroid nucleus. It is preferable that the bonding position of the two groups "-phenylene-G ³⁰ -O-" in the formula (DI-33) to the benzene ring is a meta-site or a para-site to the binding site of the steroid nucleus, respectively. In formulas (DI-32) and (DI-33), -NH ₂ bonded to a benzene ring indicates that the bonding position in the ring is arbitrary.

In Formulas (DI-34) and Formula (DI-35), G ³¹ is independently -O- or alkylene having 1 to 6 carbons, and G ³² is a single bond or alkylene having 1 to 3 carbons. R ³¹ is hydrogen or alkyl having 1 to 20 carbons, and at least one -CH ₂ -of this alkyl may be substituted with -O-, -CH = CH- or -C≡C-. R ³² is alkyl having 6 to ²² carbons, and R ³³ is hydrogen or alkyl having 1 to 22 carbons. Ring B ²⁵ is 1,4-phenylene or 1,4-cyclohexylene, and r is 0 or 1. In addition, although -NH ₂ bonded to the benzene ring indicates that the bonding position in the ring is arbitrary, it is preferable that the meta position or the para position is independent of the bonding position of G ³¹ independently.

Examples of the compound represented by formula (DI-31) are shown below.

In formulas (DI-31-1) to (DI-31-11), R ³⁴ is alkyl having 1 to 30 carbons or alkoxy having 1 to 30 carbons, preferably alkyl having 5 to 25 carbons or carbon 5 -25 alkoxy. R ³⁵ is alkyl having 1 to 30 carbons or alkoxy having 1 to 30 carbons, preferably alkyl having 3 to 25 carbons or alkoxy having 3 to 25 carbons.

In Formulas (DI-31-12) to Formula (DI-31-17), R ³⁶ is alkyl having 4 to 30 carbons, preferably alkyl having 6 to 25 carbons. R ³⁷ is alkyl having 6 to 30 carbons, preferably alkyl having 8 to 25 carbons.

In Formulas (DI-31-18) to Formula (DI-31-43), R ³⁸ is alkyl having 1 to 20 carbons or alkoxy having 1 to 20 carbons, preferably alkyl having 3 to 20 carbons or 3 carbons. It is alkoxy of -20. R ³⁹ is hydrogen, -F, alkyl of 1 to 30 carbon atoms, an alkoxy _{group, -CN, -OCH 2 F, -OCHF} 2 or -OCF ₃ group of 1 to 30 carbon atoms, and preferably having a carbon number of 3 to 25 alkyl, or It is an alkoxy having 3 to 25 carbon atoms. And G ³³ is alkylene having 1 to 20 carbons.

Examples of the compound represented by formula (DI-32) are shown below.

Examples of the compound represented by formula (DI-33) are shown below.

Examples of the compound represented by formula (DI-34) are shown below.

In the formulas (DI-34-1) to (DI-34-12), R ⁴⁰ is hydrogen or alkyl having 1 to 20 carbons, preferably hydrogen or alkyl having 1 to 10 carbons, and R ⁴¹ is hydrogen Or alkyl having 1 to 12 carbons.

Examples of the compound represented by formula (DI-35) are shown below.

In Formulas (DI-35-1) to Formula (DI-35-3), R ³⁷ is alkyl having 6 to 30 carbons, and R ⁴¹ is hydrogen or alkyl having 1 to 12 carbons.

The compounds represented by formulas (DI-36-1) to formula (DI-36-8) are shown below.

In Formulas (DI-36-1) to Formula (DI-36-8), R ⁴² each independently represents alkyl having 3 to 30 carbon atoms.

In the said diamine and dihydrazide, it says about the preferable material which improves each characteristic of the liquid crystal aligning film mentioned later. When emphasizing on further improving the alignment of the liquid crystal, formula (DI-1-3), formula (DI-5-1), formula (DI-5-5), formula (DI-5-9), Formula (DI-5-12), Formula (DI-5-13), Formula (DI-5-29), Formula (DI-6-7), Formula (DI-7-3) and Formula (DI-11 It is preferable to use the compound represented by -2). In formula (DI-5-1), m = 2, 4 or 6 is preferable, and m = 4 is more preferable. In the formula (DI-5-12), m = 2 to 6 is preferable, and m = 5 is more preferable. In formula (DI-5-13), m = 1 or 2 is preferable, and m = 1 is more preferable.

When emphasizing on improving transmittance, formula (DI-1-3), formula (DI-2-1), formula (DI-5-1), formula (DI-5-5), formula (DI- 5-24) and diamine represented by formula (DI-7-3) are preferably used, and a compound represented by formula (DI-2-1) is more preferable. In formula (DI-5-1), it is preferable that m = 2, 4 or 6, and m = 4 is more preferable. In formula (DI-7-3), m = 2 or 3, n = 1 or 2 is preferable, and m = 3 and n = 1 are more preferable.

When emphasizing on improving the VHR of a liquid crystal display element, formula (DI-2-1), formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), The compound represented by Formula (DI-4-15), Formula (DI-4-22), Formula (DI-5-28), Formula (DI-5-30), and Formula (DI-13-1) is used. It is preferable, and the diamine represented by Formula (DI-2-1), Formula (DI-5-1), and Formula (DI-13-1) is more preferable. In formula (DI-5-1), m = 1 is preferable. In the formula (DI-5-30), k = 2 is preferable.

By reducing the volume resistance value of the liquid crystal alignment film, it is effective to improve the relaxation rate of the residual charge (residual DC) in the alignment film as one of the methods for preventing burning. When this objective is emphasized, formula (DI-4-1), formula (DI-4-2), formula (DI-4-10), formula (DI-4-15), formula (DI-5- 1), formula (DI-5-12), formula (DI-5-13), formula (DI-5-28), formula (DI-4-20), formula (DI-4-21), formula ( It is preferable to use compounds represented by DI-7-12) and formula (DI-16-1), and formulas (DI-4-1), formulas (DI-5-1) and formulas (DI-5-13) ) Is more preferred. In formula (DI-5-1), m = 2, 4 or 6 is preferable, and m = 4 is more preferable. In the formula (DI-5-12), m = 2 to 6 is preferable, and m = 5 is more preferable. In formula (DI-5-13), m = 1 or 2 is preferable, and m = 1 is more preferable. In formula (DI-7-12), m = 3 or 4 is preferable, and m = 4 is more preferable.

In each diamine, a part of diamine may be substituted with monoamine in the range of the ratio of monoamine to diamine being 40 mol% or less. Such substitution may cause termination of the polymerization reaction when producing a polyamic acid, and can further inhibit the progress of the polymerization reaction. For this reason, the molecular weight of the polymer (polyamic acid or its derivative) obtained by such substitution can be easily controlled, and, for example, the effect of the present invention is not impaired and the coating properties of the liquid crystal aligning agent can be improved. The diamine substituted with monoamine may be one type or two or more types as long as the effect of the present invention is not inhibited. Examples of the monoamine include aniline, 4-hydroxyaniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, and n-nonylamine , n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n- Octadecylamine and n-acylsil amine.

The polyamic acid or derivative thereof of the present invention may further contain a monoisocyanate compound in the monomer. The molecular weight is adjusted by modifying the terminal of the polyamic acid or a derivative thereof obtained by including the monoisocyanate compound in the monomer. By using this terminal-modified polyamic acid or a derivative thereof, for example, the effect of the present invention is not impaired, and the coating properties of the liquid crystal aligning agent can be improved. It is preferable from the above viewpoint that the content of the monoisocyanate compound in the monomer is 1 to 10 mol% relative to the total amount of diamine and tetracarboxylic dianhydride in the monomer. As said monoisocyanate compound, phenyl isocyanate and naphthyl isocyanate are mentioned, for example.

<Monomers with photoreactive structure>

When the polyamic acid or its derivative of the present invention is used as a photo-alignment film to which liquid crystal alignment ability is provided by irradiation of light, for example, irradiation with ultraviolet rays, a monomer having a photoreactive structure is preferably used as a raw material for the polyamic acid and its derivatives. Can be used. By using a monomer having a photoreactive structure, polyamic acid and a derivative thereof having a photoreactive structure can be synthesized. The photoreactive structure is, for example, a photoisomerization structure represented by formulas (P-1) to (P-3) that cause isomerization by irradiation with ultraviolet light, a photolysis structure represented by the following formula (P-4) that causes decomposition, And light dimerization structures represented by formulas (P-5) to (P-7) that cause dimerization.

In formula (P-4), R ⁶¹ is independently a hydrogen atom, alkyl having 1 to 5 carbons, or phenyl.

The compound having a photoisomerization structure represented by formulas (P-1) to (P-3) is preferably at least one selected from the group of compounds represented by the following formulas (II) to (VI) with good photosensitivity: , The compound represented by formula (V) is more preferable.

In Formulas (II) to (V), R ² and R ³ are monovalent organic groups having -NH ₂ or monovalent organic groups having -CO-O-CO-, and in Formula (IV), R ⁴ is a divalent organic group, and in formula (VI), R ⁵ is independently an aromatic ring having -NH ₂ or -CO-O-CO-.

The photoisomerization structure may be included in either the main chain or the side chain of the polyamic acid or its derivative in the present invention, but by being included in the main chain, it can be preferably used for a transverse electric field type liquid crystal display device.

Materials having the photoisomerization structure include the following formulas (II-1), (II-2), (III-1), (III-2), and (IV-1) to (IV-3). , At least one selected from the group of compounds represented by formulas (V-1) to (V-3), formulas (VI-1) and (VI-2) can be preferably used.

In each of the above formulas, a group in which the bonding position is not fixed to any one carbon atom constituting the ring indicates that the bonding position in the ring is arbitrary, and in formula (IV-3), r is 1 10 is integer, and in the formula (V-2), R ⁶ is independently selected from _{-CH 3, -OCH 3, -CF 3} , -COOCH ₃ group represented by, the following formulas (P1-1), or the following formula ( Group represented by P1-2), a is independently an integer of 0 to 2, and in formula (V-3), ring A and ring B are each independently from a monocyclic hydrocarbon, a condensed polycyclic hydrocarbon or a heterocycle At least one selected, and R ¹¹ is a straight chain alkylene having 1 to 20 carbon atoms, -COO-, -OCO-, -NHCO-, -CONH-, -N (CH ₃ ) CO-, or -CON (CH ₃ ) -, R ¹² is a straight chain alkylene having 1 to 20 carbon atoms, -COO-, -OCO-, -NHCO-, -CONH-, -N (CH ₃ ) CO-, or -CON (CH ₃ )-, In R ¹¹ and R ¹² , one or two of -CH ₂ -of the straight chain alkylene may be substituted with -O-, and R ⁷ to R ¹⁰ are each independently -F, -CH ₃ , -OCH ₃ , -CF ₃ or -OH, and b to e are each independently an integer of 0 to 4.

In formulas (P1-1) and (P1-2), R ^6a to R ^8a are each independently a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted alkanoyl, or substituted or unsubstituted Arylcarbonyl. R ^6a to R ^8a may be the same or different from each other. * Represents the bonding position with respect to the benzene ring in Formula (V-2).

In the formula (P1-1), the alkyl in R ^6a may be any of straight chain, branched, and cyclic. The preferred carbon number of alkyl is 1 to 10, more preferably 1 to 6, further preferably 1 to 4, and even more preferably 1 to 3. As specific examples of alkyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylbutyl, 1-ethylpropyl, Hexyl, isohexyl, 1-methylpentyl, 1-ethylbutyl, etc. can be illustrated.

The alkanoyl in R ^6a may be any of straight chain, branched, and cyclic. The preferred carbon number of the alkanoyl is 1 to 10, more preferably 1 to 6, more preferably 1 to 2, and even more preferably 1. Specific examples of alkanoyl are methanol, ethanol, propanoyl, isopropanoyl, butanoyl, isobutanoyl, sec-butanoyl, tert-butanoyl, pentanoyl, isopentanoyl, neopentanoyl, tert-penta And noyl, 1-methylbutanoyl, 1-ethylpropanoyl, hexanoyl, isohexanoyl, 1-methylpentanoyl, 1-ethylbutanoyl, and the like.

The aryl of arylcarbonyl in R ^6a may be a monocyclic ring or a condensed ring. Aryl preferably has 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, and even more preferably 6 to 10 carbon atoms. As a specific example of aryl, phenyl, 1-naphthyl, 2-naphthyl, and the like can be exemplified. As a specific example of arylcarbonyl, phenylcarbonyl, 1-naphthylcarbonyl, etc. can be illustrated. Alkyl, alkanoyl and arylcarbonyl in R ^6a may be each substituted with a substituent. As a substituent, hydroxyl group, amino, halogeno, etc. are mentioned.

Among these, R ^6a is preferably methyl, ethyl, propyl, hydrogen, methanol, and phenyl from the viewpoint of improving the performance of the liquid crystal alignment film finally produced.

In the formula (P1-2), the description of the substituents which can be substituted with alkyl, alkanoyl, arylcarbonyl and their groups in R ^7a and R ^8a and their preferred ranges and specific examples are given in the above formula (P1- Reference can be made to the description, preferred ranges, and specific examples of the substituents that can be substituted with alkyl, alkanoyl, arylcarbonyl, and groups thereof in R ^6a of 1).

The compounds represented by the formulas (V-1), (V-2) and (VI-2) can be particularly preferably used from the viewpoint of their photosensitivity. In the formulas (V-2) and (VI-2), a compound in which the two amino bond sites are both parasites is preferred. In addition, in the formula (V-2), a compound having a = 0 and a in the substituent on one of the benzene rings is 0, and a compound having R ⁶ in the formula (p1-1) is more preferred from the viewpoint of its orientation. It can be preferably used. Moreover, the compound represented by Formula (IV-3) can also be used for purposes other than expressing photosensitivity.

Tetracarboxylic dianhydrides or diamines having a structure capable of isomerization by ultraviolet irradiation represented by formulas (II-1) to (VI-2) are represented by the following formulas (II-1-1) to (VI-2). -3).

In the formula (IV-3-1), r is an integer from 1 to 10.

When it is important to align the liquid crystal molecules in one direction, formulas (V-1-1), formulas (V-2-1), and formulas (V-2-4) to (V-2-13) And compounds represented by formulas (V-3-1) to (V-3-8) are preferred. When emphasizing on improving transmittance, compounds represented by formulas (V-2-4) to (V-2-13) and formulas (V-3-1) to (V-3-8) are used. It is desirable to do. Especially, the compound represented by Formula (V-2-1), Formula (V-2-12), and Formula (V-2-13) is more preferable at the point which expresses greater anisotropy when a liquid crystal aligning film is formed. Can be used.

As a compound which has a photolysis structure represented by Formula (P-4), the compound represented by following formula (PA-1)-Formula (PA-7) is mentioned.

In formulas (PA-4) to (PA-7), R ¹¹ is alkyl having 1 to 5 carbons.

Among these compounds, compounds represented by the formulas (PA-1) and (PA-2) are preferably used.

On the other hand, the compounds represented by formulas (PA-1) to (PA-7) are liquid crystal aligning agents using a liquid crystal aligning ability based on the photoisomerization reaction, liquid crystal aligning agents using a liquid crystal aligning ability based on light dimerization, or When used as a polymer raw material monomer used in a liquid crystal aligning agent for rubbing, it is treated as a tetracarboxylic dianhydride having no photoreactive structure.

Examples of the compound having a photoreactive structure represented by formulas (P-5) to (P-7) include diamine compounds represented by the following formulas (PDI-9) to (PDI-14).

In formula (PDI-12), R ⁵⁴ is alkyl having 1 to 10 carbons or alkoxy, and hydrogen, which is at least one of alkyl or alkoxy, may be substituted with fluorine.

The above formulas (PDI-9), (PDI-11) and formula (PDI-14) can be preferably used.

In an aspect in which a (non-photosensitive) tetracarboxylic dianhydride having no photoreactive structure and a (photosensitive) tetracarboxylic dianhydride having a photoreactive structure are used in combination, the present invention is used to prevent a decrease in the sensitivity of the alignment film to light. The photosensitive tetracarboxylic dianhydride is preferably 0 to 70 mol%, particularly preferably 0 to 50 mol%, relative to the total amount of the tetracarboxylic dianhydride used as a raw material when producing the polyamic acid or derivatives of the invention Do. In addition, two or more photosensitive tetracarboxylic dianhydrides may be used in combination to improve the above-mentioned properties such as sensitivity to light, electrical properties, and afterimage properties.

In an aspect in which (non-photosensitive) diamine having no photoreactive structure and (photosensitive) diamine having a photoreactive structure are used together, the polyamic acid of the present invention or a derivative thereof may be prepared in order to prevent a decrease in the sensitivity of the alignment film to light. The photosensitive diamine is preferably 20 to 100 mol%, particularly preferably 50 to 100 mol%, relative to the total amount of diamine used as a raw material. In addition, two or more photosensitive diamines may be used in combination to improve the above-mentioned properties, such as sensitivity to light and afterimage characteristics. As described above, the aspect of the present invention includes the case where the total amount of the tetracarboxylic dianhydride is occupied by the non-photosensitive tetracarboxylic dianhydride, but even in that case, at least 20 mol% of the total amount of the diamine is photosensitive diamine Is required.

<Liquid crystal aligning agent>

The liquid crystal aligning agent of the present invention may be composed of one type of the polyamic acid or its derivative of the present invention, or may be a mixture of two or more types of the polyamic acid or its derivative of the present invention, and the polyamic acid or its derivative of the present invention. You may mix other polymers. Other polymers include polyester, polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate. However, considering the storage stability of the liquid crystal aligning agent, the printability to the display element substrate of the liquid crystal aligning agent and the properties of the formed liquid crystal aligning film, a liquid crystal aligning agent obtained by mixing the polyamic acid of the present invention or derivatives thereof is preferable.

In the case of using such a two-component polymer, for example, an aspect in which a polymer having excellent performance in liquid crystal alignment is selected on one side and a polymer having excellent performance in improving electrical properties of the liquid crystal display device is selected on the other side. have. In this case, by controlling the structure or molecular weight of each polymer, a liquid crystal aligning agent in which these polymers are dissolved in a solvent is applied to a substrate, as described later, and is subjected to preliminary drying to form a thin film by performing liquid crystal alignment. It is possible to segregate a polymer having a polymer as an upper layer of a thin film and a polymer having excellent performance in improving electrical properties of a liquid crystal display device as a lower layer of a thin film. For this, it is possible to apply a phenomenon in which a polymer with a small surface energy is separated into an upper layer and a polymer with a large surface energy is separated into a lower layer in a mixed polymer. Confirmation of this layer separation can be confirmed that the surface energy of the formed alignment film is the same or close to the surface energy of the film formed by the liquid crystal aligning agent containing only the polymer intended to segregate into the upper layer.

As a method for expressing layer separation, there may be mentioned reducing the molecular weight of the polymer to be segregated into the upper layer.

In a liquid crystal aligning agent composed of a mixture of polyamic acids, layer separation can be expressed by forming a polymer to be segregated into an upper layer as polyimide.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid or its derivative segregating into the upper layer of the thin film can be selected without limitation from the known tetracarboxylic dianhydride exemplified above.

Tetracarboxylic dianhydrides used to synthesize polyamic acids or their derivatives segregating into the upper layer of the thin film are represented by formulas (AN-1-1), (AN-4-17) and (PA-1) The compound is preferred, and formula (AN-4-17) is more preferred. In formula (AN-4-17), m = 4 or 8 is preferable, and m = 8 is more preferable.

The diamine and dihydrazide used for synthesizing polyamic acid or a derivative thereof segregating to the upper layer of the thin film can be selected without limitation from the known diamines and dihydrozides exemplified above.

Diamines and dihydrazides used to synthesize polyamic acids or their derivatives segregating into the upper layer of the thin film include formulas (DI-4-1), formulas (DI-5-1) and formulas (DI-7-3) It is preferable to use the compound represented by. Especially, in formula (DI-5-1), m = 1, 2 or 4 is preferable and m = 4 is more preferable. In formula (DI-7-3), m = 3 and n = 1 are preferable.

The non-photosensitive diamine used for synthesizing polyamic acid or a derivative thereof segregated into the upper layer of the thin film preferably contains 30 mol% or more of aromatic diamine and more preferably 50 mol% or more of the total amount of diamine.

The acid dianhydride and diamine having the photoisomerization structure described above are preferably used for synthesizing polyamic acid or a derivative thereof segregating into the upper layer of the thin film.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid or its derivative segregating into the lower layer of the thin film can be selected without limitation from the known tetracarboxylic dianhydride exemplified above.

Tetracarboxylic dianhydrides used to synthesize polyamic acids or their derivatives segregating into the lower layer of the thin film include formula (AN-3-2), formula (AN-1-13), and formula (AN-1-1) ) And the compound represented by formula (AN-4-21) are preferable, and formula (AN-1-1) and formula (AN-3-2) are more preferable.

It is preferable that the tetracarboxylic dianhydride used to synthesize polyamic acid or a derivative thereof segregated into the lower layer of the thin film contains 10 mol% or more of aromatic tetracarboxylic dianhydride in the total amount of tetracarboxylic dianhydride. , It is more preferable to contain 30 mol% or more.

The diamine and dihydrazide used for synthesizing the polyamic acid or its derivative segregating into the lower layer of the thin film can be selected without limitation from the known diamines and dihydrozides exemplified above.

Diamine and dihydrazide used to synthesize polyamic acid or a derivative thereof segregated into the lower layer of the thin film include formulas (DI-4-1), formulas (DI-4-2), and formulas (DI-4-10) , The compounds represented by formula (DI-5-9), formula (DI-5-28), formula (DI-5-30) and formula (DIH-2-1) are preferred. Especially, in formula (DI-5-30), diamine of k = 2 is preferable.

The diamine used for synthesizing polyamic acid or a derivative thereof segregated into the lower layer of the thin film preferably contains 30% by mole or more of the aromatic diamine, and more preferably 50% by mole or more.

The polyamic acid or its derivative segregating to the upper layer of the thin film and the polyamic acid or its derivative segregating to the lower layer of the thin film are all described below as a method for synthesizing polyamic acid or a derivative thereof which is an essential component of the liquid crystal aligning agent of the present invention, respectively. It can be synthesized according to the same.

The proportion of polyamic acid or its derivatives segregating into the upper layer of the thin film relative to the total amount of polyamic acid or its derivatives separating into the upper layer of the thin film and the polyamic acid or its derivatives separating into the lower layer of the thin film is 5% to 50% by weight. Preferably, 10% by weight to 40% by weight is more preferable.

It is preferable that the concentration of the polyamic acid in the alignment agent of this invention is 0.1-40 weight%. When this alignment agent is applied to a substrate, an operation of diluting the polyamic acid contained in advance with a solvent may be necessary in order to adjust the film thickness.

The solid content concentration in the alignment agent of the present invention is not particularly limited, and an optimum value may be selected in accordance with the following various coating methods. Usually, it is preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight, based on the weight of the varnish in order to suppress unevenness and pinholes during application.

The viscosity of the liquid crystal aligning agent of this invention differs in a preferable range by the coating method, the concentration of a polyamic acid or its derivative, the type of polyamic acid or its derivative used, and the kind and ratio of a solvent. For example, in the case of application by a printing machine, 5 to 100 mPa · s is preferable, and 10 to 80 mPa · s is more preferable. When it is smaller than 5 mPa · s, it is difficult to obtain a sufficient film thickness, and when it exceeds 100 mPa · s, printing unevenness may become large. In the case of application by spin coating, 5 to 200 mPa · s is preferable, and 10 to 100 mPa · s is more preferable. When applying using an inkjet apparatus, 5-50 mPa * s is preferable, and 5-20 mPa * s is more preferable. The viscosity of the liquid crystal aligning agent is measured by a rotational viscosity measurement method, and is measured (measured temperature: 25 ° C) using, for example, a rotational viscometer (TVE-20L manufactured by Toki Sangyo Co., Ltd.).

<Alkenyl-substituted nadiimide compound>

For example, the liquid crystal aligning agent of the present invention may further contain an alkenyl-substituted nadiimide compound for the purpose of stabilizing the electrical properties of the liquid crystal display device for a long period of time. The alkenyl-substituted nadiimide compound may be used alone or in combination of two or more. The content of the alkenyl-substituted nadiimide compound is preferably from 1 to 100% by weight, more preferably from 1 to 70% by weight, and even more preferably from 1 to 50% by weight, based on the above objectives, relative to the polyamic acid or its derivatives. Do. It is preferable that the alkenyl-substituted nadiimide compound is a compound that can be dissolved in a solvent for dissolving the polyamic acid or derivatives thereof used in the present invention. Preferred alkenyl-substituted nadiimide compounds include alkenyl-substituted nadiimide compounds disclosed in JP 2013-242526A. Particularly preferred alkenyl-substituted nadiimide compounds include bis {4- (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboxyimide) phenyl} methane, N, N'-m-xylylene -Bis (allylbicyclo [2.2.1] hept-5-ene-2,3-dicarboxyimide), N, N'-hexamethylene-bis (allylbicyclo [2.2.1] hept-5-ene- 2,3-dicarboxyimide).

<A compound having a radically polymerizable unsaturated double bond>

For example, the liquid crystal aligning agent of the present invention may further contain a compound having a radically polymerizable unsaturated double bond, for the purpose of stabilizing the electrical properties of the liquid crystal display device for a long period of time. The compound having a radically polymerizable unsaturated double bond may be one kind of compound, or two or more kinds of compounds. Meanwhile, an alkenyl-substituted nadiimide compound is not included in the compound having a radically polymerizable unsaturated double bond. The content of the compound having a radically polymerizable unsaturated double bond is preferably 1 to 100% by weight, more preferably 1 to 70% by weight, and 1 to 50% by weight with respect to the polyamic acid or its derivatives from the above object. It is more preferable.

On the other hand, the ratio of a compound having a radically polymerizable unsaturated double bond to an alkenyl-substituted nadiimide compound reduces the ion density of the liquid crystal display device, suppresses an increase in ionic density over time, and also suppresses the occurrence of an afterimage. The compound / alkenyl substituted nadiimide compound having a radically polymerizable unsaturated double bond is preferably 0.1 to 10 in a weight ratio, more preferably 0.5 to 5 in weight. Preferred compounds having a radically polymerizable unsaturated double bond include compounds having a radically polymerizable unsaturated double bond disclosed in JP 2013-242526A.

<Oxazine compound>

For example, the liquid crystal aligning agent of the present invention may further contain an oxazine compound for the purpose of stabilizing electrical properties in the liquid crystal display element for a long period of time. The oxazine compound may be one kind of compound, or two or more kinds of compounds. The content of the oxazine compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight with respect to the polyamic acid or its derivatives from the above object.

The oxazine compound is soluble in a solvent in which polyamic acid or a derivative thereof is dissolved, and an oxazine compound having ring-opening polymerization property is preferable. Preferred oxazine compounds include oxazine compounds represented by formulas (OX-3-1) and (OX-3-9), as well as oxazine compounds disclosed in JP 2013-242526 A and the like.

<Oxazoline compounds>

For example, the liquid crystal aligning agent of the present invention may further contain an oxazoline compound for the purpose of stabilizing electrical properties in a liquid crystal display element for a long period of time. The oxazoline compound is a compound having an oxazoline structure. The oxazoline compound may be one kind of compound, or two or more kinds of compounds. From the above-mentioned purpose, the content of the oxazoline compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and preferably 1 to 20% by weight relative to the polyamic acid or its derivative. Alternatively, the content of the oxazoline compound is preferably from 0.1 to 40% by weight relative to the polyamic acid or its derivative when the oxazoline structure in the oxazoline compound is converted to oxazoline. Preferred oxazoline compounds include oxazoline compounds disclosed in JP 2013-242526 A and the like. More preferably, 1,3-bis (4,5-dihydro-2-oxazoline) benzene is mentioned.

<Epoxy compound>

For example, the liquid crystal aligning agent of the present invention may further contain an epoxy compound for the purpose of stabilizing the electrical properties in the liquid crystal display element for a long period of time. The epoxy compound may be one kind of compound, or two or more kinds of compounds. From the above-mentioned purpose, the content of the epoxy compound is preferably 0.1 to 50% by weight, more preferably 1 to 40% by weight, and even more preferably 1 to 20% by weight relative to the polyamic acid or its derivative. As an epoxy compound, the epoxy compound disclosed by Unexamined-Japanese-Patent No. 2013-242526 etc. is mentioned. Preferred epoxy compounds include N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxy And cyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and (3,3 ', 4,4'-diepoxy) bicyclohexyl.

<Additive>

Further, for example, the liquid crystal aligning agent of the present invention may further contain various additives. Various additives include, for example, high molecular compounds and low molecular compounds other than polyamic acid and its derivatives, and can be selected and used according to each purpose.

For example, the polymer compound includes a polymer compound soluble in an organic solvent. Adding such a polymer compound to the liquid crystal aligning agent of the present invention is preferable from the viewpoint of controlling the electrical properties and alignment of the liquid crystal aligning film to be formed. Examples of the polymer compound include polyamide, polyurethane, polyurea, polyester, polyepoxide, polyester polyol, silicone-modified polyurethane, and silicone-modified polyester.

In addition, the low-molecular compounds include, for example, 1) a surfactant for this purpose when improving coating properties, 2) an antistatic agent when improving antistatic properties, and 3) when improving adhesion to a substrate. A silane coupling agent or a titanium-based coupling agent, and 4) an imidation catalyst is mentioned when imidization proceeds at a low temperature. As a silane coupling agent, the silane coupling agent disclosed in Unexamined-Japanese-Patent No. 2013-242526 etc. is mentioned. The preferred silane coupling agent is 3-aminopropyltriethoxysilane. The imidization catalyst includes an imidization catalyst disclosed in Japanese Patent Application Laid-Open No. 2013-242526 and the like.

<Liquid crystal alignment film>

The liquid crystal aligning film of the present invention will be described in detail. The liquid crystal aligning film of this invention is a film formed by heating the coating film of the liquid crystal aligning agent of this invention mentioned above. The liquid crystal aligning film of this invention can be obtained by the usual method of manufacturing a liquid crystal aligning film from a liquid crystal aligning agent. For example, the liquid crystal aligning film of this invention can be obtained by going through the process of forming the coating film of the liquid crystal aligning agent of this invention, the process of heat-drying, and the process of heat-sintering. About the liquid crystal aligning film of this invention, you may rub and apply the anisotropy to the film obtained through a heat drying process and a heat baking process as mentioned later as needed. Alternatively, an anisotropy may be imparted by irradiating light after a coating film process or a heat-drying process as necessary, or by irradiating light after a heat-firing process. Moreover, you may use it as a liquid crystal aligning film for VA which does not perform rubbing treatment.

A coating film can be formed by apply | coating the liquid crystal aligning agent of this invention to the board | substrate in a liquid crystal display element normally like manufacture of a liquid crystal aligning film. On the substrate, electrodes such as ITO (Indium Tin Oxide), IZO (In ₂ O ₃ -ZnO), and IGZO (In-Ga-ZnO ₄ ) electrodes, glass filters that may be formed with color filters, silicon nitride, acrylic And substrates such as polycarbonate and polyimide.

As a method of applying a liquid crystal aligning agent to a substrate, a spinner method, a printing method, a dipping method, a dropping method, an inkjet method and the like are generally known. These methods are equally applicable to the present invention.

The heat-drying process is generally known as a method of heat treatment in an oven or an infrared oven, a method of heat treatment on a hot plate, and the like. It is preferable to perform a heat-drying process at the temperature within the range which can evaporate a solvent, and it is more preferable to perform at a temperature relatively low with respect to the temperature in a heat-sintering process. Specifically, the heating and drying temperature is preferably in the range of 30 ° C to 150 ° C or in the range of 50 ° C to 120 ° C.

The heating and calcining step can be performed under conditions necessary for the polyamic acid or its derivatives to exhibit a dehydration / closure reaction. The baking of the coating film is generally known as a method of heat treatment in an oven or an infrared oven, a method of heat treatment on a hot plate, and the like. These methods are equally applicable in the present invention. In general, it is preferably performed at a temperature of about 100 to 300 ° C for 1 minute to 3 hours, more preferably 120 to 280 ° C, and even more preferably 150 to 250 ° C. Further, it can be heated and fired multiple times at different temperatures. A plurality of heating devices set at different temperatures may be used, or one heating device may be used while sequentially changing to different temperatures. In the case where the heat firing is performed twice at different temperatures, it is preferable to perform at a temperature of 90 to 180 ° C for the first time and 185 ° C or more for the second time. In addition, it can be fired by changing the temperature from low temperature to high temperature. When baking is performed by changing the temperature, the initial temperature is preferably 90 to 180 ° C. The final temperature is preferably 185 to 300 ° C, more preferably 190 to 230 ° C.

In the method for forming a liquid crystal alignment film of the present invention, a known forming method such as a rubbing method or a photo-alignment method is preferably used as a means for imparting anisotropy to the alignment film in order to align the liquid crystal in one direction with respect to the horizontal and / or vertical direction Can be.

The liquid crystal aligning film of this invention using the rubbing method is a process of apply | coating the liquid crystal aligning agent of this invention to a board | substrate, the process of heat-drying the board | substrate which applied the aligning agent, the process of heat-sintering the film, and the process of rubbing a film. It can be formed through.

The rubbing treatment can usually be performed in the same manner as the rubbing treatment for the alignment treatment of the liquid crystal alignment film, and any condition that satisfies sufficient retardation in the liquid crystal alignment film of the present invention can be used. Preferred conditions are 0.2 to 0.8 mm in the amount of foot indentation, 5 to 250 mm / sec in stage movement speed, and 500 to 2,000 rpm in roller rotation speed.

The method of forming the liquid crystal alignment film of the present invention by the photo-alignment method will be described in detail. The liquid crystal aligning film of this invention using the photo-alignment method can be formed by heating and drying a coating film, and then irradiating linearly polarized or unpolarized radiation of the film to impart anisotropy to the coated film and heat-sintering the film. Alternatively, it can be formed by heating and drying the coating film, followed by heating and firing, by irradiating linearly polarized or non-polarized radiation. From the viewpoint of orientation, it is preferable to perform the irradiation process of radiation before the heating and firing process.

Further, in order to increase the liquid crystal alignment ability of the liquid crystal alignment film, linear polarization or no polarization of radiation may be irradiated while heating the coating film. Irradiation of radiation may be performed in a process of heating and drying the coating film or in a process of heating and firing, or may be performed between a heat drying process and a heat firing process. The heating and drying temperature in the step is preferably in the range of 30 ° C to 150 ° C or in the range of 50 ° C to 120 ° C. Moreover, it is preferable that the heating and firing temperature in the said process is the range of 30 to 300 degreeC, or the range of 50 to 250 degreeC.

As the radiation, for example, ultraviolet or visible light containing wavelength light of 150 to 800 nm can be used, but ultraviolet light containing light of 300 to 400 nm is preferable. Further, linearly polarized or non-polarized light can be used. These lights are not particularly limited as long as they are light capable of imparting liquid crystal alignment ability to the coating film, but linear polarization is preferable when it is desired to express strong alignment regulating force with respect to the liquid crystal.

The liquid crystal aligning film of the present invention can exhibit high liquid crystal aligning ability even under low energy light irradiation. The irradiation amount of the linearly polarized light in the radiation irradiation step is preferably 0.05 to 20 J / cm 2, and more preferably 0.5 to 10 J / cm 2. In addition, the wavelength of the linearly polarized light is preferably 200 to 400 nm, and more preferably 300 to 400 nm. Although the angle of irradiation of the linearly polarized light to the film surface is not particularly limited, when it is desired to express strong alignment control force to the liquid crystal, it is preferable from the viewpoint of reducing the alignment treatment time that it is as perpendicular to the film surface as possible. In addition, the liquid crystal aligning film of the present invention can align the liquid crystal in a direction perpendicular to the polarization direction of the linearly polarized light by irradiating linearly polarized light.

Ultra high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, deep UV lamps, halogen lamps, metal halide lamps, high power metal halide lamps, xenon lamps, mercury xenon Lamps, excimer lamps, KrF excimer lasers, fluorescent lamps, LED lamps, sodium lamps, microwave-excited electrodeless lamps, etc. can be used without limitation.

The liquid crystal aligning film of this invention is obtained preferably by the method which further contains other processes other than the process mentioned above. For example, the liquid crystal aligning film of the present invention does not require a process of cleaning the film with a cleaning solution after firing or irradiation, but a cleaning process can be formed according to the circumstances of other processes.

Examples of the cleaning method using the cleaning solution include brushing, jet spraying, steam cleaning, or ultrasonic cleaning. These methods may be performed alone or in combination. As the cleaning solution, pure or various alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene and xylene, halogen-based solvents such as methylene chloride, ketones such as acetone and methyl ethyl ketone It can be used, but is not limited to these. Needless to say, these cleaning liquids are used with a small amount of sufficiently purified impurities. Such a cleaning method can also be applied to the cleaning step in forming the liquid crystal alignment film of the present invention.

In order to improve the liquid crystal alignment ability of the liquid crystal aligning film of the present invention, heat or light annealing treatment may be used before and after the heating and firing process, before and after the rubbing process, or before or after irradiation with polarized or unpolarized radiation. In the annealing treatment, the annealing temperature is 30 to 180 ° C, preferably 50 to 150 ° C, and the time is preferably 1 minute to 2 hours. In addition, a UV lamp, a fluorescent lamp, an LED lamp, etc. are mentioned as annealing light used for annealing treatment. It is preferable that the irradiation amount of light is 0.3 to 10 J / cm 2.

Although the film thickness of the liquid crystal aligning film of this invention is not specifically limited, It is preferable that it is 10-300 nm, and it is more preferable that it is 30-150 nm. The film thickness of the liquid crystal aligning film of this invention can be measured with a well-known film thickness measuring apparatus, such as a step meter or an ellipsometer.

The liquid crystal aligning film of the present invention is characterized by having anisotropy of a particularly large orientation. The size of the anisotropy can be evaluated by a method using polarized IR described in JP 2005-275364 A. Moreover, it can also evaluate according to the method using an ellipsometer, as shown in the following Example. In detail, the retardation value of a liquid crystal aligning film can be measured with a spectroscopic ellipsometer. The retardation value of the film increases in proportion to the degree of orientation of the polymer main chain. That is, it is considered that the one having a large retardation value has a large degree of orientation and, when used as a liquid crystal alignment film, an alignment film having a larger anisotropy has a large orientation regulating force for the liquid crystal composition.

The liquid crystal aligning film of this invention can be used conveniently for a transverse electric field type liquid crystal display element. When used in a transverse electric field type liquid crystal display element, the smaller the Pt angle and the higher the liquid crystal alignment ability, the higher the black display level in the dark state, and the higher the contrast. The Pt angle is preferably 0.1 ° or less.

The liquid crystal aligning film of the present invention can be used for alignment control of liquid crystal compositions for liquid crystal displays, such as smartphones, tablets, in-vehicle monitors, and televisions. It can be used for the alignment control of an optical compensation material or all other liquid crystal materials in addition to the alignment purpose of the liquid crystal composition for liquid crystal displays. In addition, since the alignment film of the present invention has great anisotropy, it can be used alone as an optical compensation material.

<Liquid crystal display element>

The liquid crystal display element of the present invention will be described in detail. The present invention is a pair of substrates disposed opposite to each other, an electrode formed on one or both sides of each of the opposing surfaces of the pair of substrates, and a liquid crystal alignment film formed on the opposing surfaces of each of the pair of substrates. And in the liquid crystal display element which has the liquid crystal layer formed between the said pair of board | substrate, the liquid crystal display element which the said liquid crystal aligning film is the alignment film of this invention is provided.

The electrode is not particularly limited as long as it is an electrode formed on one surface of the substrate. Examples of such electrodes include ITO and metal vapor deposition films. Further, the electrode may be formed on the entire surface of one side of the substrate, or may be formed in a desired shape that is patterned, for example. Examples of the desired shape of the electrode include a comb-shaped or zigzag structure. The electrodes may be formed on one of the pair of substrates or on both substrates. The form of the electrode is different depending on the type of the liquid crystal display element. For example, in the case of the IPS type liquid crystal display element, an electrode is disposed on one side of the pair of substrates. Electrodes are arranged on both sides of a pair of substrates. The liquid crystal alignment layer is formed on the substrate or electrode.

The liquid crystal layer is formed in a form in which the liquid crystal composition is held by the pair of substrates on which the surfaces on which the liquid crystal alignment film is formed are opposed. For the formation of the liquid crystal layer, a spacer that forms an appropriate gap between the pair of substrates such as fine particles or a resin sheet can be used as necessary.

As a method of forming the liquid crystal layer, a vacuum injection method and an ODF (One Drop Fill) method are known.

In the vacuum injection method, voids (cell gaps) are formed so that the alignment film faces each other, leaving an injection hole of the liquid crystal, printing a seal, and adhering the substrate. After filling and filling the liquid crystal using a vacuum differential pressure in the cell gap partitioned by the substrate surface and the sealing agent, the injection port is sealed to manufacture a liquid crystal display element.

In the ODF method, a sealing agent is printed on the outer periphery of one alignment film surface of a pair of substrates, liquid crystals are dropped on the inner region of the sealing agent, and the other substrate is adhered so that the alignment film surfaces face each other. Then, the liquid crystal is pressed and extended on the front surface of the substrate, and then ultraviolet light is irradiated on the front surface of the substrate to cure the sealing agent, thereby producing a liquid crystal display element.

In addition to the UV curing type, a thermal curing type is also known as a sealing agent used for bonding a substrate. The sealing agent can be printed, for example, by a screen printing method.

There is no restriction | limiting in particular in a liquid crystal composition, Various liquid crystal compositions with positive or negative dielectric anisotropy can be used. Preferred liquid crystal compositions having positive dielectric anisotropy include Japanese Patent No. 3086228, Japanese Patent No. 2635435, Japanese Patent Publication No. 5-501735, Japanese Patent Publication No. 8-157826, Japanese Patent Publication No. 8-231960 No. 9-241644 (EP885272A1), JP 9-302346 (EP806466A1), JP 8-199168 (EP722998A1), JP 9-235552 , Japanese Patent Application Publication No. Hei 9-255956, Japanese Patent Application Publication No. Hei 9-241643 (EP885271A1), Japanese Patent Application Publication No. Hei 10-204016 (EP844229A1), Japanese Patent Application Publication No. Hei 10-204436, Japanese Patent Application And liquid crystal compositions disclosed in Japanese Unexamined Patent Publication No. Hei 10-231482, Japanese Unexamined Patent Publication No. 2000-087040, Japanese Unexamined Patent Publication No. 2001-48822, and the like.

The preferred examples of the liquid crystal composition having negative dielectric anisotropy are Japanese Patent Application Publication No. 57-114532, Japanese Patent Application Publication No. 2-4725, Japanese Patent Application Publication No. 4-224885, Japanese Patent Application Publication No. 8 -40953, Japanese Patent Publication No. Hei 8-104869, Japanese Patent Publication No. Hei 10-168076, Japanese Patent Publication No. Hei 10-168453, Japanese Patent Publication No. Hei 10-236989, Japanese Patent Publication No. Hei 10 -236990, Japanese Patent Publication No. Hei 10-236992, Japanese Patent Publication No. Hei 10-236993, Japanese Patent Publication No. Hei 10-236994, Japanese Patent Publication No. Hei 10-237000, Japanese Patent Publication No. Hei 10 -237004, Japanese Patent Publication No. Hei 10-237024, Japanese Patent Publication No. Hei 10-237035, Japanese Patent Publication No. Hei 10-237075, Japanese Patent Publication No. Hei 10-237076, Japanese Patent Publication No. Hei 10 -237448 (EP967261A1), Japanese Patent Application Publication No. Hei 10-287874, Japanese Patent Application Publication No. Hei 10-287875, Japanese Patent Application Publication No. Hei 10-291945, Japanese Patent Application Publication No. Hei 11-029581, Japanese Patent Application Publication No. Hei 11-080049, Japanese Patent Application Publication No. 2000-256307, Japanese Patent Application Publication No. 2001-019965, Japanese Patent Application Publication No. 2001-072626, Japanese Patent Application Publication No. 2001-192657, Japanese Patent Application Publication No. 2010-037428 No. 2011/024666, International Publication No. 2010/072370, Japanese Patent Publication No. 2010-537010, Japanese Patent Publication No. 2012-077201, Japanese Patent Publication No. 2009-084362, etc. Can be heard.

Addition of one or more kinds of optically active compounds to the liquid crystal composition having a dielectric constant anisotropy is negative or negative, and there is no problem.

By using the liquid crystal composition having negative dielectric anisotropy in the liquid crystal display element of the present invention, it is possible to provide a liquid crystal display element having excellent afterimage characteristics and good alignment stability.

Moreover, for example, the liquid crystal composition used for the liquid crystal display element of this invention may add an additive further from a viewpoint of improving orientation, for example. Such additives are photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, antifoaming agents, polymerization initiators, polymerization inhibitors, and the like. Preferred photopolymerizable monomers, optically active compounds, antioxidants, ultraviolet absorbers, pigments, antifoaming agents, polymerization initiators, polymerization inhibitors include compounds disclosed in International Publication No. 2015/146330.

In order to be suitable for a liquid crystal display device in a polymer sustained alignment (PSA) mode, a polymerizable compound can be mixed in the liquid crystal composition. Preferred examples of the polymerizable compound are compounds having polymerizable groups such as acrylate, methacrylate, vinyl compound, vinyloxy compound, propenyl ether, epoxy compound (oxirane, oxetane), and vinyl ketone. Preferred compounds include compounds disclosed in International Publication No. 2015/146330 and the like.

Example

Hereinafter, the present invention will be described by examples. On the other hand, the evaluation methods and compounds used in Examples are as follows.

<Evaluation Method>

1. Weight average molecular weight (Mw)

The weight average molecular weight of the polyamic acid was measured by GPC method using a 2695 Separation Module 2414 Differential Refractometer (manufactured by Waters), and determined by polystyrene conversion. The obtained polyamic acid was diluted with a phosphoric acid-DMF mixed solution (phosphoric acid / DMF = 0.6 / 100: weight ratio) so that the polyamic acid concentration was about 2% by weight. As the column, HSPgel RT MB-M (manufactured by Waters) was used, and the mixed solution was measured under conditions of a column temperature of 50 ° C and a flow rate of 0.40 mL / min as a developer. TSK standard polystyrene manufactured by Tosoh Corporation was used as the standard polystyrene.

2. Evaluation of Wet Diffusion by Drop Test

Nichipet EX PlusII manufactured by NICHIRYO (capacity range: 0.5 to 10 µl) was fitted with BioPointe Scientific manufactured Pipette Tips (Volume: 20 µl), and 10 µl of the polyamic acid solution (hereinafter, varnish) prepared in the method described below was filled, and ITO (Indium tin oxide) It was dripped on a vapor-deposited glass substrate, left to stand for 4 minutes after dripping, and then dried for 10 minutes on a hot plate at 60 ° C. Then, the diameter of the coating film was measured with a ruler, and the wet diffusion was evaluated by the following judgment criteria.

Criteria for judging wet spread by drop test

Less than 38 mm ×

38 mm or more and less than 42 mm △

42 mm or more and less than 45 mm ○

45㎜ or more ◎

3. Evaluation of streak unevenness in inkjet printing

A polyamic acid solution (hereinafter, varnish) prepared in the method described below using an inkjet device EB100XY100 manufactured by Konica Minolta Co., Ltd. was printed on an ITO (indium tin oxide) deposited glass substrate, the substrate was left for 3 minutes after printing, and a 60 ° C hot plate Phase was dried for 80 seconds. Thereafter, the presence or absence of stripe unevenness of the coating film was visually confirmed.

4. Solvent resistance test of flexographic printing plate

After measuring the weight of the cut flexographic printing plate, it was immersed in an evaluation solvent and left for 24 hours. After 24 hours, the weight of the immersed flexographic printing plate was measured, and the swelling rate of the flexographic printing plate with a solvent was calculated using the following formula (1A). In addition, the shape of the dipped flexo printing plate was visually confirmed. It can be said that a solvent having a low swelling rate and not changing the shape of the flexographic printing plate is a solvent that is difficult to impart damage to the flexographic printing plate.

Flexo printing plate: APR production flexo printing plate (APR is a registered trademark)

   1.5 cm x 1.5 cm

Solvent amount: 30 times the weight of the flexographic printing plate

Leave time: 24 hours

5. Flexo printing applicability test

The polyamic acid solution (hereinafter referred to as varnish) prepared in the method described below was transferred to a flexographic printing plate, left for 2 minutes, and then printed on the ITO side of the glass substrate on which ITO was deposited on one side. After printing, it was allowed to stand for 2 minutes and dried on a hot plate at 60 ° C for 80 seconds. Thereafter, the presence or absence of unevenness of the coating film was visually confirmed. The printing conditions are as follows.

Printing machine: Komura Tech SmartLabo-III

Flexo printing plate: APR production Flexo printing plate (APR is a registered trademark)

Substrate: ITO (indium tin oxide) deposited glass substrate

Application area: 20 mm × 20 mm

A case where bad staining occurred badly, but a hardness case was good, and a case where it did not occur was made the best.

<Tetracarboxylic dianhydride>

<Diamine>

<Solvent>

NMP: N-methyl-2-pyrrolidone

GBL: γ-butyrolactone

BC: Butyl cellosolve

BP: 1-butoxy-2-propanol

EDM: Diethylene glycol ethyl methyl ether

DIBK: Diisobutyl ketone

MIBC: 4-methyl-2-pentanol

ETB: Ethylene glycol monobutyl butyl ether (Formula (1-1))

EIB: Ethylene glycol monoisobutyl ether (formula (1-2))

EIP: Ethylene glycol monoisopropyl ether (formula (1-3))

BDM: Diethylene glycol butyl methyl ether

 <Additive>

Add.1: 1,3-bis (4,5-dihydro-2-oxazolyl) benzene

Add. 2: 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane

<Synthesis of polyamic acid>

[Synthesis Example A-1]

In a 200 mL brown four-necked flask equipped with a thermometer, stirrer, feed inlet and nitrogen gas inlet, 3.2786 g of compound represented by formula (V-2-1), formula (DI-5-1) (m = 2) 0.6148 g of the compound shown, 0.2591 g of the compound represented by the formula (DI-13-1) and 68.0 g of dehydrated NMP were added and dissolved under stirring under a stream of dry nitrogen. Subsequently, 7.8475 g of a compound represented by formula (AN-4-17) (m = 8) and 80.0 g of dehydrated NMP were further added and stirring was continued at room temperature for 24 hours. 40.0 g of BC was added to the reaction solution to obtain a varnish having a solid content concentration of 6% by weight. Let this varnish be (PA-1). The weight average molecular weight of the polyamic acid contained in (PA-1) was 10,200.

[Synthesis Examples A-2 to A-8]

Varnishes (PA-2) to (PA-8) were prepared according to Synthesis Example A-1, except that the composition of tetracarboxylic dianhydride, diamine and solvent was changed. Table 1 shows the composition ratios of the raw materials and the solvent together with (PA-1). In the table of this example, the composition ratio of the solvent is expressed as a weight percentage including the solid content concentration of the varnish.

[Synthesis Example B-1]

3.8246 g of compound represented by formula (DI-13-1) and 1.7122 g of compound represented by formula (DI-5-9) in a 200 mL brown four-necked flask equipped with a thermometer, stirrer, feed inlet and nitrogen gas inlet, 0.6165 g of the compound represented by the formula (DI-4-1) and 48.0 g of dehydrated NMP were added, and stirred and dissolved under a stream of dry nitrogen. 3.6708 g of the compound represented by formula (AN-1-1), 2.1760 g of the compound represented by formula (AN-3-2), and 100.0 g of dehydrated NMP were added, and stirring was continued at room temperature for 24 hours. 40.0 g of BC was added to the reaction solution, and a varnish having a solid content concentration of 6% by weight was obtained. Let this varnish be (PB-1). The weight average molecular weight of the polyamic acid contained in (PB-1) was 50,200.

[Synthesis Examples B-2, B-3 and B-6]

Varnishes (PB-2), (PB-3) and (PB-6) were prepared in accordance with Synthesis Example B-1, except that the solvent composition was changed. Table 2 shows the composition ratios of the raw materials and the solvent together with (PB-1).

[Synthesis Examples B-4 and B-5]

Varnishes (PB-4) and (PB-5) having a solid content concentration of 8.4% by weight were prepared according to Synthesis Example B-1, except that the tetracarboxylic dianhydride, diamine, solvent composition, and solid content concentration were changed. Table 2 shows the composition ratios of the raw materials and the solvent together with (PB-1).

<Varnish blend>

[Synthesis Example C-1]

[A] The varnish (PA-1) prepared in Synthesis Example A-1 and [B] the varnish (PB-1) prepared in Synthesis Example B-1 were [A] / [B] = 3.0 / 7.0 (weight ratio). Mixed. The mixed solution was further diluted in various solvents, and the solid content concentration was 4.0% by weight, whereby the additive (Add.1) was 10 parts by weight relative to the solid content concentration of the varnish, and the additive (Add.2) was added to the solid content concentration of the varnish. With respect to 10 parts by weight. Let the obtained varnish be (PC-1).

[Synthesis Examples C-2 to C-25]

[A] One selected from varnishes (PA-1) to (PA-8) and [B] one selected from varnishes (PB-1) to (PB-6) [A] / [B] = 3.0 /7.0 (weight ratio), and further diluted with various solvents, the solid content concentration of 4.0% by weight varnish (PC-1) to (PC-16), solid content concentration of 5.5% by weight varnish ( PC-17)-(PC-25) were prepared. In addition, additives Add.1 and Add.2 were added to the varnish (PC-4), (PC-6), (PC-16) and (PC-24). Add. 1 and Add. 2 were each added in 10 parts by weight based on the solid content concentration of the varnish. Table 3 shows the varnish used, the composition ratio of the solvent (% by weight) and the amount of the additive added (PC-1).

[Example 1]

<Evaluation of Wet Diffusion by Drop Test>

The varnish (PC-6) having a solid content concentration of 4.0 wt% prepared as a blend was subjected to a drop test by the method described above as a liquid crystal aligning agent. Table 4 shows the results.

<Evaluation of striped unevenness in inkjet (IJ) printing>

Further, the varnish (PC-6) was inkjet printed by the method described above. Table 4 shows the results.

[Examples 2 to 11 and Comparative Examples 1 to 5]

Except for changing the varnish used as a liquid crystal aligning agent, wet diffusion by a drop test and unevenness in inkjet (IJ) printing were evaluated by a method according to Example 1. The results are shown in Table 4 together with Example 1.

As shown in Table 4, in Examples 1 to 11 using varnishes ((PC-6) to (PC-16)) containing ETB, EIB and / or EIP as the specific poor solvent (A) of the present invention, The evaluation result of wet diffusion in the drop test was ◎ or ○ in the above evaluation method. In addition, even in the evaluation of the striped unevenness in inkjet printing, the striped unevenness was not generated in the coating film, and favorable results were obtained. Further, even in the varnish (PC-6) to which the additive was added, the evaluation result of the wet diffusion in the drop test was good, and even in the evaluation of the striped unevenness in inkjet printing, the striped unevenness did not occur in the coating film. It was a good result. On the other hand, in Comparative Examples 1 to 5 using varnishes ((PC-1) to (PC-5)) containing BC or BP having similar structures to those of ETB, EIB and / or EIP, in the drop test, Wet diffusion is Δ or × in the above evaluation method, the wet diffusing property is poor, and even in the evaluation of the striped unevenness in inkjet printing, in Comparative Examples 2, 3, and 5, striped unevenness occurred in the coating film, and good wet diffusion and stripes The stain prevention could not be made compatible.

[Reference Example 1]

<Solvent resistance test of flexographic printing plate>

NMP was used as the solvent, and the solvent resistance test of the flexographic printing plate was conducted by the method described above. Table 5 shows the results.

[Reference Examples 2 and 3, Examples 12 to 14, Comparative Examples 6 to 8]

GBL, BC, ETB, EIB, EIP, EDM, BDM and BP were evaluated by the method according to Reference Example 1 except that the solvent used for the evaluation was changed. The results are shown in Table 5 together with Reference Example 1.

In Examples 12 to 14, the swelling ratio was as low as 6.6% to 10.6%, and no change in the plate after immersion was observed. On the other hand, in Comparative Examples 6 to 8, the swelling ratio was a very high value of 19.1% to 63.9%, and after immersion, the warpage of the plate was confirmed. From the above results, it was found that ETB, EIB, and EIP are difficult to swell the flexographic printing plate, and it is difficult to impart damage to the flexographic printing plate. On the other hand, EDM, BDM, BP, the swelling rate of the flexographic printing plate is high, and after immersion, it was confirmed that the flexure printing plate is deformed, so that it is easy to deform the flexographic printing plate and impart damage.

[Example 15]

<Applicability test of flexo printing>

The varnish (PC-17) having a solid content concentration of 5.5 wt% prepared as a blend was subjected to a coating property test of flexographic printing by the method described above as a liquid crystal aligning agent. Table 6 shows the results.

[Examples 16 to 21, Comparative Examples 9 and 10]

The coating property was evaluated by the method according to Example 15 except having changed the varnish used as a liquid crystal aligning agent. The results are shown in Table 6 together with Example 15.

As shown in Table 6, in Examples 15 to 21, unevenness was not generated and the printability was good. On the other hand, in Comparative Examples 9 and 10, occurrence of unevenness was confirmed. When flexo printing was performed using the varnish containing ETB, EIB, and / or EIP, which is the specific poor solvent (A) of the present invention, it was confirmed that the coatability was good.

The liquid crystal aligning agent provided by the present invention has good wet diffusivity, excellent printability, suppresses the occurrence of unevenness in the coating film, and can form a liquid crystal alignment film having a more uniform film thickness. A high quality liquid crystal display element can be manufactured by the liquid crystal aligning film formed using the liquid crystal aligning agent of this invention.

Claims (9)

A liquid crystal aligning agent containing a polymer and a solvent which are reaction products from tetracarboxylic dianhydride and diamine,
A liquid crystal aligning agent containing at least one specific poor solvent (A), wherein the solvent is selected from the group of compounds represented by formula (1):

In the formula, R ¹ is isopropyl, isobutyl or t-butyl, and
R ² is alkylene having 2 to 4 carbons. According to claim 1,
Liquid crystal aligning agent which specific poor solvent (A) is a compound represented by Formula (1-1)

. The method of claim 1 or 2,
Among the above solvents, as a good solvent, selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, and N-ethyl-2-pyrrolidone. A liquid crystal aligning agent containing at least one. The method according to any one of claims 1 to 3,
As a poor solvent other than the specific poor solvent (A), butyl cellosolve, 1-butoxy-2-propanol, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, diisobutyl A liquid crystal aligning agent containing at least one selected from the group consisting of ketone and 4-methyl-2-pentanol. The method according to any one of claims 1 to 4,
The liquid crystal aligning agent whose ratio of a specific poor solvent (A) is 0.1-60 weight% with respect to the total solvent weight. The method according to any one of claims 1 to 5,
When a solvent other than the specific poor solvent (A) is included, the ratio of the good solvent is 20 to 89% by weight based on the total solvent weight. A method for forming a liquid crystal alignment film comprising the step of applying the liquid crystal aligning agent of any one of claims 1 to 6 by inkjet printing or flexographic printing. A method for forming a liquid crystal alignment film comprising a step of applying, drying, and firing the liquid crystal aligning agent according to any one of claims 1 to 6. The manufacturing method of the liquid crystal display element including the process of forming the liquid crystal aligning film of Claim 7 or 8.