JP2022068884A - Coating liquid for functional polymer film formation and functional film - Google Patents

Abstract

To provide coating liquid for a functional polymer film formation capable of obtaining a functional polymer film whose various properties have been improved relatively freely, and a functional polymer film using the same; and to provide a liquid crystal aligning agent excellent in electric characteristics and sealant adhesiveness exhibited in use as a liquid crystal display as one of their applications.SOLUTION: Coating liquid for functional polymer film formation contains a polymer being a reactant between a modification compound represented by the following formula and a polymer to be modified. In the formula, W1 expresses a k1-valent organic group being a functional structure portion imparting functionality, and k1 indicates an integer number of 1 to 8.SELECTED DRAWING: None

Description

The present invention relates to a coating liquid for forming a functional polymer film and a functional film.

Polyimide is widely used as a protective material, an insulating material, and a functional material used in various devices in the electric and electronic fields because of its high mechanical strength, heat resistance, and solvent resistance. A typical example of a functional material application is a liquid crystal alignment film that plays an important role in orienting a liquid crystal in a liquid crystal display element represented by a liquid crystal television or a smartphone.
Polyimide can be obtained, for example, by thermally and chemically imidizing a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine, but in functional material applications where various properties are required, the polyimide can be obtained. By variously changing the structure of the diamine as a raw material, various properties are imparted to the obtained polyimide film.

For example, in the above-mentioned liquid crystal alignment film field, among the techniques for controlling the pretilt angle by the structure of the polyimide, the method of using a diamine having a side chain as a part of the polyimide raw material has a pretilt angle according to the usage ratio of the diamine. Since it can be controlled, it is relatively easy to set the target pretilt angle, and it is useful as a means for increasing the pretilt angle. The side chain structure of the diamine that increases the pretilt angle of the liquid crystal includes a long-chain alkyl group or fluoroalkyl group (see, for example, Patent Document 1), a cyclic group or a combination of a cyclic group and an alkyl group (see, for example, Patent Document 2). A steroid skeleton (see, for example, Patent Document 3) and the like are known.

Japanese Unexamined Patent Publication No. 2-282726 Japanese Unexamined Patent Publication No. 3-179323 Japanese Unexamined Patent Publication No. 4-281427

However, when changing the structure of diamine in various ways, there are some that are difficult to synthesize, and when diamine and tetracarboxylic acid dianhydride are reacted to polymerize polyamic acid, due to steric obstacles and the like. The polymerization does not proceed sufficiently, and as a result, the desired diamine component cannot be freely used, and as a result, the desired functionality may not be sufficiently imparted to the polymer.
An object of the present invention is to solve the above-mentioned problems, and a coating liquid for forming a functional polymer film capable of obtaining a functional polymer film having various properties improved relatively freely, and a coating liquid using the same. It is an object of the present invention to provide a method for forming a functional polymer film.

The present inventors have arrived at the present invention as a result of diligent studies to solve the above problems.
The coating liquid for forming a functional polymer film of the present invention comprises a functional structural moiety that imparts functionality and at least one NHS ester structural moiety linked to the functional structural moiety, and a modifying compound of the following formula. It is obtained by reacting with a modifying polymer.

In the formula, W ₁ represents a k-valent organic group which is a functional structural site that imparts functionality, and k ₁ represents an integer of ₁ to 8.

According to the present invention, N-hydroxysuccinimide is eliminated by the reaction between the amino group present at the terminal of the polyamic acid and the NHS ester structure, and various functionalities are provided at the terminal of the polyamic acid polymer via an amide bond. It is possible to introduce structural parts. This makes it possible to further improve the degree of freedom in imparting various functions to the polyimide polymer.

<Modifying compound>
The modifying compound of the present invention is a compound of the following formula (A).

In the formula, W ₁ represents a k-valent organic group which is a functional structural site that imparts functionality, and k ₁ represents an integer of ₁ to 8. It is preferably 1 to 2.

As for the structure of W ₁ , it is possible to freely select a structure that expresses the function desired to be imparted to the polymer to be modified. Taking the example of imparting a function to a liquid crystal alignment film using polyimide as a polymer to be modified, the heat or photocrosslinkable group required for improving the mechanical strength of the liquid crystal alignment film, the liquid crystal alignment film of the liquid crystal It is conceivable to introduce _a long-chain side chain group or the like necessary for the expression of the tilt angle (pre-tilt angle) into W1.

The specific structure of (A) is listed below, but the structure is not limited to this, and a structure capable of expressing the functionality required for various functional membranes can be arbitrarily introduced.
Generally, NHS esters are synthesized by a condensation reaction of N-hydroxysuccinimide and a carboxylic acid. As the condensing agent, DCC (dicyclohexylcarbodiimide) and EDC (1-ethyl-3- (3-dimethylaminopropyl) -carbodiimide) are frequently used.

<Polymer for modification>
The modifying polymer of the present invention is not particularly limited as long as it has a reaction point with the above-mentioned modifying compound. Specific examples include polyamic acids, polyamic acid esters, polyimides, polyureas, and polyamides. From the viewpoint as a liquid crystal alignment agent, at least one selected from a polyimide precursor containing a structural unit represented by the following formula (6) and a polyimide as an imidized product thereof is more preferable. More preferably, it is a polyamic acid.

In the above formula (6), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from a diamine, and R ₄ is a hydrogen atom or 1 to 1 to carbon atoms. It is an alkyl group of 5. _R4 is preferably a hydrogen atom, a methyl group or an ethyl group from the viewpoint of ease of imidization by heating.
<Tetracarboxylic acid derivative>
X ₁ in the polyimide precursor of the above formula (6) is a tetravalent organic group derived from a tetracarboxylic acid derivative. Examples of the tetracarboxylic acid derivative include not only tetracarboxylic acid dianhydride but also its derivatives such as tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester, and tetracarboxylic acid dialkyl ester dihalide. Among them, the one represented by the following formula (7) is preferable.

In the formula (7), X ₁ is the same as the definition of X ₁ in the above formula (6), and its structure is not particularly limited. Preferred specific examples include the following formulas (X1-1) to (X1-44).

In the formulas (X1-1) to (X1-4), R ₃ to R ₂₃ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, and an alkenyl group having 2 to 6 carbon atoms. It is an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. From the viewpoint of liquid crystal orientation, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and preferably a hydrogen atom or a methyl group.

Specific examples of the formula (X1-1) include the following formulas (X1-1-1) to (X1-1-6). (X1-1-1) is particularly preferable from the viewpoint of liquid crystal orientation and sensitivity of photoreaction.

The tetracarboxylic acid derivative used in the modifying polymer of the present invention is appropriately selected according to the solubility and coatability of the polymer in a solvent and the degree of properties required for a functional film, and is the same. One type may be used in the polymer, or two or more types may be mixed.
<Diamine>
In the above formula (6), Y ₁ is a divalent organic group derived from diamine, and the diamine is represented by the following formula (8).

In the formula, A ₁ and A ₂ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms.
Further, Y ₁ is appropriately selected according to the solubility and coatability of the polymer in a solvent and the degree of characteristics required for a functional film, and two or more types are mixed in the same polymer. May be.
Specific examples of Y ₁ are as shown below, but are not limited thereto.

<Coating liquid for forming a functional polymer film>
The coating liquid for forming a functional polymer film of the present invention contains a polymer (hereinafter, also referred to as a specific polymer) which is a reaction product of the above-mentioned modifying compound and the polymer to be modified.
The production of a specific polymer will be described by taking a polyamic acid as an example.
The specific polymer of the present invention can be obtained by adding a modifying compound to the obtained polyamic acid solution and stirring the mixture.
The concentration of the polyamic acid solution is preferably 4 to 25% by mass, more preferably 10 to 20% by mass, still more preferably 12 to 15% by mass.
The amount of the modifying compound added is preferably 0.01 to 0.1 equivalent, preferably 0.02 to 0, based on 1 equivalent of the amino group in the diamine involved in the polymerization reaction among the diamines used in the production of the polyamic acid. 0.08 equivalents are more preferred. As a basic catalyst for accelerating the reaction between the amino group and the NHS ester, a tertiary amine such as TEA (triethylamine), DIPEA (diisopropylethylamine), DBU (diazabicycloundecene) may be added.
The temperature at the time of stirring is preferably −20 ° C. to 50 ° C., more preferably 0 ° C. to 30 ° C.
The stirring time is preferably 10 minutes to 108 hours, more preferably 1 hour to 72 hours.
By the above steps, a polyamic acid solution in which the terminal amine of the polyamic acid is sealed can be obtained. Further, by performing a known imidization step on the polyamic acid in which the terminal amine is sealed, a polyimide in which the terminal amine is sealed can be obtained.

<Liquid crystal alignment agent>
The coating liquid for forming a functional polymer film of the present invention can be used for various devices due to the function of imparting it. A liquid crystal alignment agent used in the manufacture of a liquid crystal display element is preferable as one of its uses. The liquid crystal alignment agent of the present invention contains the coating liquid for forming the functional polymer film of the present invention, and various solvents and compounds used as necessary.
The liquid crystal alignment agent of the present invention contains the above-mentioned specific polymer, but may contain two or more kinds of specific polymers having different structures. Further, in addition to the specific polymer, another polymer, that is, a polymer having no divalent group represented by the formula (1) may be contained. The types of polymers include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth) acrylate. And so on. When the liquid crystal alignment agent of the present invention contains other polymers, the ratio of the specific polymer to the total polymer components is preferably 5% by mass or more, and examples thereof include 5 to 95% by mass.

The liquid crystal alignment agent generally takes the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal alignment agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent for dissolving the polymer component. At that time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed by setting the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 1% by mass or more is preferable, and from the viewpoint of storage stability of the solution, 10% by mass or less is preferable. A particularly preferable concentration of the polymer is 2 to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-. It is imidazolidinone, methylethylketone, cyclohexanone, cyclopentanone and the like. Of these, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

Further, as the organic solvent contained in the liquid crystal alignment agent of the present invention, in addition to the above solvent, a solvent that improves the coatability when the liquid crystal alignment agent is applied and the surface smoothness of the coating film can be used. Specific examples of such an organic solvent are given below.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-Pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol , 2-Heptanol, 3-Heptanol, 1-Octanol, 2-Octanol, 2-Ethyl-1-hexanol, Cyclohexanol, 1-Methylcyclohexanol, 2-Methylcyclohexanol, 3-Methylcyclohexanol, 2,6- Dimethyl-4-heptanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2, 3-Butandiol, 1,5-Pentanediol, 2-Methyl-2,4-Pentanediol, 2-Ethyl-1,3-hexanediol, Diisopropyl ether, Dipropyl ether, Dibutyl ether, Dihexyl ether, Dioxane, Ethylene Glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyetane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2- Pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutylacetate, 1-methylpentylacet Tart, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl Ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, plu Lopyrene glycol, propylene glycol monobutyl ether, 1- (butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, di Propropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetylate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate , Diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, acetate Ethyl, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate , 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionic acid, butyl 3-methoxypropionic acid, lactic acid methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester And so on.

Among them, the organic solvents are 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, and ethylene. It is preferable to use glycol monobutyl ether or dipropylene glycol dimethyl ether. The type and content of such a solvent are appropriately selected depending on the coating device for the liquid crystal alignment agent, coating conditions, coating environment, and the like.

The liquid crystal alignment agent of the present invention may additionally contain a component other than the polymer component and the organic solvent. Such additional components include an adhesion aid for increasing the adhesion between the liquid crystal alignment film and the substrate, the adhesion between the liquid crystal alignment film and the sealing material, a cross-linking agent for increasing the strength of the liquid crystal alignment film, and liquid crystal. Examples thereof include a dielectric and a conductive substance for adjusting the dielectric constant and electric resistance of the alignment film. Specific examples of these additional components include antisolvents and crosslinkable compounds disclosed in paragraph 53 [0104] to paragraph 60 [0116] of International Publication No. 2015/060357.

Examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include functional silane-containing compounds and epoxy group-containing compounds, and examples thereof include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-. Glycydoxypropyltriethoxysilane 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-) Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl- 3-Aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4 , 7-Triazadecane, 10-triethoxysilyl-1,4,7-Triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N -Benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (Oxyethylene) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol Diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5, 6-Tetraglycidyl-2,4-hexanediol, N, N, N', N',-tetraglycidyl-m-xylene diamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane or N , N, N', N',-tetraglycidyl-4, 4'-diaminodiphenylmethane and the like.

Further, the liquid crystal alignment agent of the present invention may contain the following additives in order to increase the mechanical strength of the liquid crystal alignment film.

The above additive is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. If it is less than 0.1 part by mass, the effect cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal is lowered, so that it is more preferably 0.5 to 20 parts by mass.

In addition to the above, the liquid crystal alignment agent of the present invention includes a polymer other than the specific polymer described in the present invention, a dielectric for changing electrical properties such as the dielectric constant and conductivity of the liquid crystal alignment film, and a liquid crystal alignment film. A silane coupling agent for the purpose of improving the adhesion between the substrate and the substrate, a crosslinkable compound for the purpose of increasing the hardness and density of the liquid crystal alignment film, and a polyimide precursor when firing the coating film. It may contain an imidization accelerator or the like for the purpose of efficiently advancing imidization by heating.
<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is obtained from the liquid crystal alignment agent. To give an example of a method of obtaining a liquid crystal alignment film from a liquid crystal alignment agent, a liquid crystal alignment agent in the form of a coating liquid is applied to a substrate, dried, and fired, and the obtained film is subjected to a rubbing treatment method or a photoalignment treatment. An example is a method of performing orientation treatment by a method.

The substrate to which the liquid crystal alignment agent is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with the glass substrate and the silicon nitride substrate. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed, from the viewpoint of simplifying the process. Further, in the reflective liquid crystal display element, if only one side of the substrate is used, an opaque object such as a silicon wafer can be used, and in this case, a material that reflects light such as aluminum can also be used for the electrode.

Industrially, the method of applying the liquid crystal alignment agent is generally screen printing, offset printing, flexographic printing, inkjet method or the like. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method, a spray method, and the like, and these may be used depending on the purpose.

After applying the liquid crystal alignment agent on the substrate, the solvent is evaporated and fired by a heating means such as a hot plate, a heat circulation type oven, or an IR (infrared) type oven. Any temperature and time can be selected for the drying and firing steps after applying the liquid crystal alignment agent. Although the drying step is not always required, it is preferable to perform the drying step when the time from coating to firing is not constant for each substrate or when firing is not performed immediately after coating. For this drying, the solvent may be removed to the extent that the shape of the coating film is not deformed by transporting the substrate, and the drying means is, for example, hot at a temperature of 40 ° C. to 150 ° C., preferably 60 ° C. to 100 ° C. A method of drying on a plate for 0.5 to 30 minutes, preferably 1 to 5 minutes can be mentioned.

The firing temperature of the coating film formed by applying the liquid crystal alignment agent is, for example, 100 to 350 ° C, preferably 120 to 300 ° C, and more preferably 150 ° C to 250 ° C. The firing time is 5 minutes to 240 minutes, preferably 10 minutes to 90 minutes, and more preferably 20 minutes to 90 minutes. The heating can be performed by a generally known method, for example, a hot plate, a hot air circulation furnace, an infrared furnace, or the like.

If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may decrease. Therefore, the thickness is preferably 5 to 300 nm, more preferably 10 to 200 nm.

When manufacturing a TN type, STN type, IPS type or FFS type liquid crystal display element, a process of imparting a liquid crystal alignment ability to the coating film formed in the above step is performed. The alignment ability-imparting treatment includes a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, and cotton, and photoalignment in which the coating film is irradiated with polarized or unpolarized radiation. Processing etc. can be mentioned.

In the photo-alignment treatment, as the radiation to irradiate the coating film, for example, ultraviolet rays including light having a wavelength of 150 to 800 nm and visible light can be used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation to be used is linearly polarized light or partially polarized radiation, the irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from an oblique direction, or may be performed in combination thereof. When irradiating unpolarized radiation, the direction of irradiation is diagonal.

As the light source to be used, for example, a low pressure mercury lamp, a high pressure mercury lamp, a heavy hydrogen lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excima laser, an LED lamp and the like can be used. Ultraviolet rays in a preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter, a diffraction grating, or the like. The irradiation amount of radiation is preferably 100 to 50,000 J / m ² , and more preferably 300 to 20,000 J / m ² .

Further, the light irradiation on the coating film may be performed while heating the coating film in order to enhance the reactivity. The temperature at the time of heating is usually 30 to 250 ° C, preferably 40 to 200 ° C, and more preferably 50 to 150 ° C.

The photo-alignment treatment may be performed by heat treatment at the time of light irradiation, or may be performed by heat treatment after the photo-alignment treatment. The heating temperature at this time is preferably 80 to 300 ° C, more preferably 120 to 250 ° C. The heating time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. Further, instead of the heat treatment, a cleaning treatment with an organic solvent or water may be performed, or the cleaning treatment and the heat treatment may be combined.

The liquid crystal alignment film after the rubbing treatment is further subjected to a process of changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet rays, or a part of the surface of the liquid crystal alignment film. After forming the resist film, the rubbing treatment may be performed in a direction different from that of the previous rubbing treatment, and then the resist film may be removed so that the liquid crystal alignment film has a different liquid crystal alignment ability for each region. In this case, it is possible to improve the visibility characteristics of the obtained liquid crystal display element.

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a liquid crystal display element of a transverse electric field type such as an IPS method or an FFS (Fringe Field Switching) method.
<Liquid crystal display element>
In the liquid crystal display element of the present invention, after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal cell is produced by a known method, and the liquid crystal cell is used as an element. Specific examples of the liquid crystal display element that can be manufactured include two substrates arranged so as to face each other, a liquid crystal layer provided between the substrates, and a liquid crystal alignment of the present invention provided between the substrates and the liquid crystal layer. It is a liquid crystal display element including the liquid crystal cell having the liquid crystal alignment film formed by the agent. More specifically, the liquid crystal alignment agent of the present invention is applied onto two substrates and fired to form a liquid crystal alignment film, and the two substrates are arranged so that the liquid crystal alignment films face each other. It is a liquid crystal display element in which a liquid crystal layer composed of liquid crystal is sandwiched between these two substrates, that is, the liquid crystal layer is provided in contact with the liquid crystal alignment film.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Specifically, a transparent substrate is prepared, and then a liquid crystal alignment film is formed on each substrate under the conditions as described above. As described above, the substrate is usually a substrate on which a transparent electrode for driving a liquid crystal display is formed. As a specific example, the same substrate as that described in the liquid crystal alignment film can be mentioned.

A common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes and are patterned so as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a film made of SiO ₂ -TiO ₂ formed by the sol-gel method.

When manufacturing an IPS type or FFS type liquid crystal display element, an electrode forming surface of a substrate provided with an electrode made of a transparent conductive film or a metal film patterned in a comb tooth shape and a facing substrate not provided with an electrode. A liquid crystal alignment agent is applied to one surface thereof, and then each coated surface is heated to form a coating film. As the metal film, a film made of a metal such as chromium can be used.

Further, in a high-performance element such as a TFT type element, an element having an element such as a transistor formed between an electrode for driving a liquid crystal display and a substrate is used.

In the case of a transmissive liquid crystal display element, it is common to use a substrate as described above, but in a reflective liquid crystal display element, an opaque substrate such as a silicon wafer may be used if only one side of the substrate is used. It is possible. At that time, a material such as aluminum that reflects light can be used for the electrodes formed on the substrate.

On the other hand, the liquid crystal material constituting the liquid crystal layer of the horizontally oriented liquid crystal display element such as IPS or FFS is a liquid crystal material conventionally used in the horizontally oriented method, for example, MLC-2003 or MLC-2041 manufactured by Merck. Negative-positive liquid crystals and negative liquid crystals such as MLC-6608 can also be used.

As a method of sandwiching the liquid crystal layer between two substrates, a known method can be mentioned. For example, a pair of substrates on which a liquid crystal alignment film is formed is prepared, and spacers such as beads are sprayed on the liquid crystal alignment film of one substrate so that the surface on the side where the liquid crystal alignment film is formed is on the inside. Another method is to bond the other substrate together and inject the liquid crystal under reduced pressure to seal it. In addition, a pair of substrates on which the liquid crystal alignment film is formed is prepared, spacers such as beads are sprayed on the liquid crystal alignment film of one substrate, liquid crystal is dropped, and then the surface on the side where the liquid crystal alignment film is formed. A liquid crystal cell can also be produced by a method in which the other substrate is bonded and sealed so that the surface is on the inside. The thickness of the spacer is preferably 1 to 30 μm, more preferably 2 to 10 μm.

After the above steps are completed, the polarizing plate is installed in the liquid crystal cell. Specifically, it is preferable to attach a pair of polarizing plates to the surfaces of the two substrates opposite to the liquid crystal layer.

The liquid crystal alignment film and the liquid crystal display element of the present invention are not limited as long as the liquid crystal alignment agent of the present invention is used, and may be manufactured by other known methods. The process of obtaining a liquid crystal display element from a liquid crystal alignment agent is disclosed in, for example, pages 17 [0074] to 19 [0081] of Japanese Patent Application Laid-Open No. 2015-135393.

The liquid crystal display element of the present invention can be effectively applied to various devices, for example, a clock, a portable game, a word processor, a notebook computer, a car navigation system, a camcorder, a PDA, a digital camera, a mobile phone, a smartphone, and the like. It can be used for various display devices such as various monitors, LCD TVs, and information displays.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The abbreviations of the compounds and the measurement method of each characteristic in the following are as follows.
(solvent)
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve (diamine)
DA-1: p-phenylenediamine DA-2: 1,2-bis (4-aminophenoxy) ethane DA-3: Refer to the following formula (DA-3) DA-4: N-tert-butoxycarbonyl-N- ( 2- (4-Aminophenyl) ethyl) -N- (4-aminobenzyl) amine DA-5: 4,4'-diaminodiphenylamine DA-6: 1,3-bis (4-aminophenethyl) urea DA-7 : 4- (2-Methylaminoethyl) aniline (acid dianhydride)
TA-1: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride TA-2: 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride TA-3: 3, 3', 4,4'-biphenyltetracarboxylic acid dianhydride (NHS ester)
EC-1: 4-benzoylbenzoic acid N-succinimidyl EC-2: 4-azido-2,3,5,6-tetrafluorobenzoic acid N-succinimidyl

[viscosity]
The viscosity of the solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) at a sample volume of 1.1 mL, a cone rotor TE-1 (1 ° 34', R24), and a temperature of 25 ° C.
[Making a liquid crystal cell]
A liquid crystal cell having a configuration of a Fringe Field Switching (FFS) mode liquid crystal display element is manufactured.

First, a substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. An ITO electrode having a solid pattern, which constitutes a counter electrode as a first layer, is formed on the substrate. A SiN (silicon nitride) film formed by a CVD method is formed as a second layer on the counter electrode of the first layer. The film thickness of the SiN film of the second layer is 500 nm, and it functions as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an ITO film as a third layer is arranged on the SiN film of the second layer to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 6 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-like shape formed by arranging a plurality of dogleg-shaped electrode elements having a bent central portion. The width of each electrode element in the lateral direction is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrodes forming each pixel are configured by arranging a plurality of bent dogleg-shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but in the central portion like the electrode elements. It has a shape that resembles a bold dogleg that bends. Then, each pixel is divided into upper and lower parts with a bent portion in the center as a boundary, and has a first region on the upper side and a second region on the lower side of the bent portion.

Comparing the first region and the second region of each pixel, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrodes are formed so as to form an angle (clockwise) of + 10 ° in the first region of the pixel, and the pixel is formed in the second region of the pixel. The electrode elements of the electrodes are formed so as to form an angle of −10 ° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotational movement (inplane switching) of the liquid crystal in the substrate surface induced by the voltage application between the pixel electrode and the counter electrode are mutual. It is configured to be in the opposite direction.
Next, after filtering the liquid crystal alignment agent with a 1.0 μm filter, a spin coat is applied to the prepared substrate with electrodes and a glass substrate having a columnar spacer having a height of 4 μm on which an ITO film is formed on the back surface. It was applied in. After drying on a hot plate at 80 ° C. for 2 minutes, the film was baked in a hot air circulation oven at 230 ° C. for 30 minutes to form a coating film having a film thickness of 100 nm. The coating film surface was irradiated with ultraviolet rays having a wavelength of 254 nm, which were linearly polarized and had an extinction ratio of 10: 1 or more, via a polarizing plate. This substrate was fired in a hot air circulation oven at 230 ° C. for another 30 minutes to obtain a substrate with a liquid crystal alignment film. The above two substrates are made into a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film surfaces face each other and the orientation direction is 0 °, and then the sealant is applied. It was cured to prepare an empty cell. A liquid crystal MLC-3019 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour, left overnight, and then used for each evaluation.
[Afterimage evaluation by long-term AC drive]
Using the liquid crystal cell described above, an AC voltage of ± 5 V was applied for 120 hours at a frequency of 60 Hz in a constant temperature environment of 60 ° C. Then, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left as it was at room temperature for one day.

After leaving it for a day, a liquid crystal cell is installed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the backlight is turned on with no voltage applied, so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted as described above. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became the darkest to the angle at which the first region became the darkest was calculated as the angle Δ. Similarly, in the second pixel, the second region and the first region were compared and the same angle Δ was calculated.
[Evaluation of seal adhesion]
A sample for evaluating the seal adhesion was prepared as follows. First, a liquid crystal alignment agent was applied to an ITO substrate having a size of 30 mm × 40 mm by spin coating. Subsequently, after drying on a hot plate at 80 ° C. for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 30 minutes to form a coating film having a film thickness of 100 nm. Next, the coating film surface was irradiated with ultraviolet rays having a wavelength of 254 nm linearly polarized with an extinction ratio of 10: 1 or more via a polarizing plate. Finally, firing was performed in a hot air circulation oven at 230 ° C. for 30 minutes to obtain a substrate with a liquid crystal alignment film.

After applying a 4 μm bead spacer on the substrate surface of the obtained substrate with the liquid crystal alignment film, a sealing agent (723K1 manufactured by Kyoritsu Kagaku Co., Ltd.) was dropped onto the center of the substrate. Next, the substrate with the liquid crystal alignment film and the ITO substrate without the liquid crystal alignment film were bonded so that the substrates overlapped with each other in a cross shape. At that time, the amount of the sealant dropped was adjusted in advance so that the diameter of the sealant after bonding was 2 mm. The two pasted boards were fixed with clips. The substrate was irradiated with ultraviolet rays having a wavelength of 365 nm at 3.0 J / cm ² to photo-cure the seal, and the seal was thermally cured at 150 ° C. for 1 hour.

The substrate peeling test was performed with a tabletop precision universal testing machine AGS-X 500N manufactured by Shimadzu Corporation. Of the two boards stuck together in a cross, both ends of one board are fixed to the device, and both ends of the other board are grasped with a jig and pulled up, and the force (N) when the two boards are peeled off is measured. bottom. The peeling stress (N / mm ² ) was calculated by dividing the peeling force (N) by the area of the applied sealant.
<Synthesis example 1>
In a 200 ml four-necked flask equipped with a stirrer and a nitrogen introduction tube, 1.08 g (10.0 mmol) of diamine DA-1, 3.66 g (15.0 mmol) of diamine DA-2, and 4. diamine DA-3. 81 g (15.0 mmol) and diamine DA-4 were weighed in 3.41 g (15.0 mmol), 132.0 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 10.54 g (47.0 mmol) of carboxylic acid dianhydride TA-1 was added, and NMP was further added so that the solid content concentration became 12% by mass, and the temperature was 40 ° C. for 20 hours. Stirring gave a polyamic acid solution (PAA-1). The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 380 mPa · s.
<Synthesis example 2>
60.0 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was dispensed into a 200 ml Erlenmeyer flask, 20.0 g of NMP was added thereto, and then 4.56 g of acetic anhydride and 1 of pyridine were added. .18 g was added and reacted at 55 ° C. for 3 hours. This reaction solution was poured into 300 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidization rate of this polyimide was 66%. A polyimide solution (SPI-1) was obtained by adding 26.4 g of NMP to 3.6 g of the obtained polyimide powder and stirring at 60 ° C. for 20 hours to dissolve the powder.
<Synthesis example 3>
In a 50 mL Erlenmeyer flask, weigh 29.0 g of polyamic acid (PAA-1) and 0.190 g (0.59 mmol) of NHS ester EC-1, with respect to 1 equivalent of amino groups in the diamine involved in the polymerization reaction. 04 equivalent) was added. The mixture was stirred at 25 ° C. for 72 hours to obtain a polyamic acid solution (PAA-1_EC1) in which the terminal amine was sealed by the reaction of the amine and the NHS ester EC-1.
<Synthesis example 4>
In a 50 mL Erlenmeyer flask, weigh 29.0 g of polyamic acid (PAA-1) and 0.195 g (0.59 mmol) of NHS ester EC-2, 0. 04 equivalent) was added. The mixture was stirred at 25 ° C. for 72 hours to obtain a polyamic acid solution (PAA-1_EC2) in which the terminal amine was sealed by the reaction of the amine and the NHS ester EC-2.
<Synthesis Example 5>
15.0 g of the polyamic acid solution (PAA-1_EC2) obtained in Synthesis Example 4 was separated into a 50 ml Erlenmeyer flask, 5.0 g of NMP was added thereto, and then 1.14 g of acetic anhydride and 0 of pyridine were added. .29 g was added and reacted at 55 ° C. for 3 hours. This reaction solution was poured into 64 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidization rate of this polyimide was 64%. A polyimide solution (SPI-1_EC2) was obtained by adding 10.3 g of NMP to 1.4 g of the obtained polyimide powder and stirring at 60 ° C. for 20 hours to dissolve it.
<Synthesis example 6>
Weigh 3.9 g (20.0 mmol) of diamine DA-5, 1.49 g (5.0 mmol) of diamine DA-6 in a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube, and 78.0 g of NMP. In addition, nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 6.77 g (23.0 mmol) of carboxylic acid dianhydride TA-3 was added, and NMP was further added so that the solid content concentration became 12% by mass, and the temperature was 70 ° C. for 20 hours. Stirring gave a polyamic acid solution (PAA-2).
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 420 mPa · s.
<Synthesis example 7>
Take 9.01 g (60.0 mmol) of DA-7 and 26.8 g (89.8 mmol) of DA-6 in a 500 mL four-necked flask with a stirrer and a nitrogen introduction tube, add 290 g of NMP, and add nitrogen. Was stirred and dissolved while feeding. While stirring this diamine solution under water cooling, 27.9 g (142 mmol) of DC-2 was added, 71.4 g of NMP was added, and the mixture was stirred at 23 ° C. for 2 hours to obtain a polyamic acid solution (PAA-3). ..
The viscosity of this polyamic acid solution at a temperature of 25 ° C. was 750 mPa · s.
<Example 1>
4.17 g of the 12 mass% polyamic acid solution (PAA-1_EC1) obtained in Synthesis Example 3 is placed in a 20 ml Erlenmeyer flask, 2.83 g of NMP and 3.00 g of BCS are added, and the mixture is mixed at 25 ° C. for 2 hours to obtain a liquid crystal display. An orienting agent (A1) was obtained. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
<Examples 2 and 3>
The liquid crystal alignment agent (A2) was carried out in the same manner as in Example 1 except that the polyamic acid solution (PAA-1_EC2) and the polyimide solution (SPI-1_EC2) were used instead of the polyamic acid solution (PAA-1_EC1). ), (A3) was obtained.
<Example 4>
2.00 g of the 12% by mass polyamic acid solution (PAA-1_EC2) obtained in Synthesis Example 4 and 3.00 g of the 12% by mass polyamic acid solution (PAA-2) obtained in Synthesis Example 6 in a 20 ml Erlenmeyer flask. 3.40 g of NMP and 3.60 g of BCS were added and mixed at 25 ° C. for 2 hours to obtain a liquid crystal alignment agent (A4). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
<Example 5>
2.00 g of the 12% by mass polyamic acid solution (PAA-1_EC2) obtained in Synthesis Example 4 and 2.40 g of the 15% by mass polyamic acid solution (PAA-3) obtained in Synthesis Example 7 were placed in a 20 ml Erlenmeyer flask. Then, 4.00 g of NMP and 3.60 g of BCS were added and mixed at 25 ° C. for 2 hours to obtain a liquid crystal alignment agent (A4). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
<Comparative Example 1>
4.17 g of the 12 mass% polyamic acid solution (PAA-1) obtained in Synthesis Example 1 is placed in a 20 ml Erlenmeyer flask, 2.83 g of NMP and 3.00 g of BCS are added, and the mixture is mixed at 25 ° C. for 2 hours to obtain a liquid crystal display. An orienting agent (B1) was obtained. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
<Comparative Example 2>
A liquid crystal alignment agent (B2) was obtained by carrying out the same procedure as in Comparative Example 1 except that the polyimide solution (SPI-2) was used instead of the polyamic acid solution (PAA-1).
<Comparative Example 3>
2.00 g of the 12% by mass polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 3.00 g of the 12% by mass polyamic acid solution (PAA-2) obtained in Synthesis Example 6 were placed in a 20 ml Erlenmeyer flask. 3.40 g of NMP and 3.60 g of BCS were added and mixed at 25 ° C. for 2 hours to obtain a liquid crystal alignment agent (B3). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.
<Comparative Example 4>
2.00 g of the 12% by mass polyamic acid solution (PAA-1) obtained in Synthesis Example 1 and 2.40 g of the 15% by mass polyamic acid solution (PAA-3) obtained in Synthesis Example 7 were placed in a 20 ml Erlenmeyer flask. Then, 4.00 g of NMP and 3.60 g of BCS were added and mixed at 25 ° C. for 2 hours to obtain a liquid crystal alignment agent (B4). No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the solution was uniform.

<Example 6>
After filtering the liquid crystal alignment agent (A1) obtained in Example 1 with a 1.0 μm filter, it has the prepared substrate with electrodes and a columnar spacer having a height of 4 μm on which an ITO film is formed on the back surface. It was applied to a glass substrate by spin coating. After drying on a hot plate at 80 ° C. for 2 minutes, the film was baked in a hot air circulation oven at 230 ° C. for 30 minutes to form a coating film having a film thickness of 100 nm. The coating film surface was irradiated with 0.3 J / cm ² of ultraviolet rays having a wavelength of 254 nm linearly polarized at an extinction ratio of 26: 1 via a polarizing plate. This substrate was fired in a hot air circulation oven at 230 ° C. for 30 minutes to obtain a substrate with a liquid crystal alignment film.
The two obtained substrates were combined into a set, a sealant was applied onto one substrate, and the other substrate was laminated so that the liquid crystal alignment film surfaces faced each other and the orientation direction was 0 °. After that, the sealant was cured to prepare an empty cell. A liquid crystal MLC-3019 (manufactured by Merck & Co., Inc.) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell.
[Afterimage evaluation by long-term AC drive]
An AC voltage of ± 5 V was applied to the above liquid crystal cell at a frequency of 60 Hz in a constant temperature environment of 60 ° C. for 120 hours. After applying the AC voltage for 120 hours, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left at room temperature for one day. After that, when the angle Δ in this liquid crystal cell was measured, the value of the angle Δ was 0.11 degrees.

[Evaluation of seal adhesion]
A liquid crystal alignment agent (A1) was applied to an ITO substrate of 30 mm × 40 mm by spin coating. Subsequently, after drying on a hot plate at 80 ° C. for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 30 minutes to form a coating film having a film thickness of 100 nm. Next, the coating film surface was irradiated with 0.3 J / cm ² of ultraviolet rays having a wavelength of 254 nm linearly polarized at an extinction ratio of 26: 1 via a polarizing plate. Finally, firing was performed in a hot air circulation oven at 230 ° C. for 30 minutes to obtain a substrate with a liquid crystal alignment film.

After applying a 4 μm bead spacer on the substrate surface of the obtained substrate with the liquid crystal alignment film, a sealing agent (723K1 manufactured by Kyoritsu Kagaku Co., Ltd.) was dropped onto the center of the substrate. Next, the substrate with the liquid crystal alignment film and the ITO substrate without the liquid crystal alignment film were bonded so that the substrates overlapped with each other in a cross shape. At that time, the amount of the sealant dropped was adjusted in advance so that the diameter of the sealant after bonding was 2 mm. The two pasted boards were fixed with clips. The substrate was irradiated with ultraviolet rays having a wavelength of 365 nm at 3.0 J / cm ² to photo-cure the seal, and the seal was thermally cured at 150 ° C. for 1 hour.

The substrate peeling test was performed with a tabletop precision universal testing machine AGS-X 500N manufactured by Shimadzu Corporation. Of the two boards stuck together in a cross, both ends of one board were fixed to the device, and both ends of the other board were grasped with a jig and pulled up, and the two boards were peeled off at 23.9 (N). .. From the area of the sealant (7.02 mm ² ), the peel stress was calculated to be 3.40 (N / mm ² ).
<Examples 6 and 7, Comparative Example 5>
The afterimage and seal adhesion by long-term AC drive were evaluated by the same method as in Example 6 except that the liquid crystal alignment agents (A2) and (B1) were used instead of the liquid crystal alignment agent (A1). carried out. Table 2 shows the results of evaluation of afterimages by long-term AC drive, and Table 3 shows the evaluation results of seal adhesion.
<Examples 8, 9, 10 and Comparative Examples 6, 7, 8>
Exactly the same method as in Example 6 except that the liquid crystal alignment agents (A3), (A4), (A5), (B2), (B3), and (B4) were used instead of the liquid crystal alignment agent (A1). Then, the seal adhesion was evaluated. Table 3 shows the evaluation results of the seal adhesion.

From the comparison between Examples 6 and 7 and Comparative Example 5, the liquid crystal alignment agents A1 and A2 whose amine ends were modified with NHS ester had better seal adhesion than the liquid crystal alignment agent B1 whose ends were not modified. It turns out that the sex is high. By introducing a functional moiety into the amine terminal of the polymer using the NHS ester having a functional structural moiety in this way, a liquid crystal alignment agent having excellent afterimage by long-term AC drive and excellent seal adhesion can be obtained. It turned out that it was possible. Further, from the comparison between Examples 8, 9, and 10 and Comparative Examples 6, 7, and 8, the polyimide liquid crystal alignment agent obtained by chemically imidizing the polyamic acid having the functional structural site introduced at the terminal, and the terminal. It was found that a liquid crystal alignment agent blended with a polyamic acid having a functional structural site introduced and a polyamic acid having no functional structural site introduced can also have an effect of improving the seal adhesion.

By using the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment film having high seal adhesion while suppressing afterimages caused by AC drive in the IPS and FFS drive type liquid crystal display elements. Therefore, it can be expected to be used in liquid crystal display elements that require high display quality.

Claims (6)

A coating liquid for forming a functional polymer film containing a polymer which is a reaction product of the modifying compound of the following formula and the polymer to be modified.

In the formula, W ₁ represents a k-valent organic group which is a functional structural site that imparts functionality, and k ₁ represents an integer of ₁ to 8. The coating liquid for forming a functional polymer film according to claim 1, wherein the polymer to be modified is selected from polyamic acid, polyamic acid ester, and polyimide. A functional polymer film obtained from the coating liquid for forming a functional polymer film according to claim 1 or 2. A liquid crystal alignment agent containing the coating liquid for forming a functional polymer film according to any one of claims 1 to 3. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 4. A liquid crystal display element comprising the liquid crystal alignment film according to claim 5.