WO2018092811A1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

Provided is a liquid crystal aligning agent which enables the achievement of a liquid crystal alignment film that has high film hardness, good afterimage characteristics and the like. A liquid crystal aligning agent which contains the component (A) and the component (B) described below, and an organic solvent. Component (A): A polyimide which is an imidized product of a polyimide precursor that is a reaction product of a tetracarboxylic acid derivative component and a diamine component containing a diamine having a structure of formula (1), and which has an imidization rate of from 20% to 80%. (In the formula, * represents a bond with another atom or group.) Component (B): A compound which has two or more crosslinkable functional groups.

Description

Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element

The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the liquid crystal aligning film.

The liquid crystal alignment film is a film for controlling the alignment of liquid crystal molecules in a certain direction in a phase difference plate using a liquid crystal display element or a polymerizable liquid crystal. For example, a liquid crystal display element has a structure in which liquid crystal molecules forming a liquid crystal layer are sandwiched between liquid crystal alignment films formed on the surfaces of a pair of substrates. Then, the liquid crystal molecules are aligned in a certain direction with a pretilt angle by the liquid crystal alignment film, and respond by applying a voltage to the electrode provided between the substrate and the liquid crystal alignment film. As a result, the liquid crystal display element displays a desired image using the orientation change due to the response of the liquid crystal molecules. The liquid crystal alignment film is a main constituent member together with liquid crystal molecules and the like in the liquid crystal display element.

There are various properties required for the liquid crystal alignment film. High resistance to rubbing is one of the important characteristics. The rubbing process is known as a method of forming a liquid crystal alignment film from a polymer film formed on a substrate in the manufacturing process of a liquid crystal display element, and is still widely used industrially today. In the rubbing process, an alignment process is performed by rubbing the surface of the polymer film formed on the substrate with a cloth.
In this rubbing treatment, there is a known problem that dust generated by scraping the liquid crystal alignment film or scratches on the liquid crystal alignment film deteriorates the display quality of the display element. Therefore, the liquid crystal alignment film is required to have a resistance to rubbing (rubbing resistance) that the film hardness is high.

As a method for forming a liquid crystal alignment film having high rubbing resistance, a polymer obtained by reacting tetracarboxylic dianhydride and an amine compound and / or an imidized polymer thereof, and two in a molecule It is known that a liquid crystal alignment film having a constant pretilt angle can be obtained regardless of rubbing conditions by using a liquid crystal aligning agent containing a compound having the above epoxy group (see Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 07-234410 Japanese Unexamined Patent Publication No. 10-338880

In recent years, liquid crystal display elements have been rapidly reduced in weight and thickness for mobile applications such as smartphones and mobile phones. Along with this, in the manufacture of a liquid crystal panel, a so-called “sliming process” is often performed in which the glass substrate of the liquid crystal panel after manufacture is polished. In this step, there are a chemical method using hydrofluoric acid and a physical polishing method using an abrasive.
When physically polishing, the produced liquid crystal panel may be bent depending on the apparatus used for polishing, and as a result, stress is applied to the liquid crystal alignment film from all directions. Therefore, when the mechanical strength of the liquid crystal alignment film is weak, the film breaks particularly around the column spacer, which may cause a defect. Conventional liquid crystal alignment films having sufficient resistance to the rubbing treatment often have insufficient resistance to the slimming process.
The main object of the present invention is not only the rubbing process but also the slimming process, and has a large film hardness that can suppress film scraping and breakage, and has a high yield in liquid crystal panel manufacturing, and an IPS driving method. Another object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having excellent electrical characteristics capable of reducing an afterimage caused by alternating current drive generated in a liquid crystal display element of an FFS driving system.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the gist of the present invention is to provide a liquid crystal aligning agent characterized by containing the following component (A), component (B) and an organic solvent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, and the liquid crystal aligning film. It is in the liquid crystal display element used.
(A) component: an imidized product of a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative component and a diamine component containing a diamine having the structure of the following formula (1), and an imidization rate of 20% to Polyimide that is 80%.

(In the formula, * represents a bond with another atom or group.)
(B) Component: A compound having two or more crosslinkable functional groups.

With the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having high film hardness and good afterimage characteristics can be obtained. Therefore, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has a high yield in liquid crystal panel production, and can reduce afterimages due to alternating current drive generated in liquid crystal display elements of IPS drive method and FFS drive method, An IPS driving type or FFS driving type liquid crystal display element having excellent afterimage characteristics can be obtained.

<(A) component>
The component (A) contained in the liquid crystal aligning agent of the present invention is an imidized product of a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative component and a diamine component containing a diamine having the structure of the above formula (1). And a polyimide having an imidization ratio of 20% to 80%.

Examples of the diamine having the structure of the formula (1) include a structure in which amino groups are bonded to both ends of the benzene ring in the formula (1). In that case, the amino group bonded to both ends of the benzene ring is independently bonded to the ortho, meta, or para position with respect to —O—CH ₂ —O—. Of these, all of the amino groups are preferably bonded to the para position with respect to —O—CH ₂ —O—.
The ratio of the diamine having the structure of the formula (1) in the total diamine component to be reacted with the tetracarboxylic acid derivative component is preferably 10 to 80 mol% in order to better achieve the object of the present invention. More preferably, it is 20 to 60% by mole, and particularly preferably 20 to 50%.

The diamine component for obtaining a polyimide precursor can contain 1 type, or 2 or more types of other diamine other than the diamine which has a structure of Formula (1). Such other diamines can be represented by the following formula (6).

In the above formula (6), 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. is there. From the viewpoint of liquid crystal orientation, A ₁ and A ₂ are preferably a hydrogen atom or a methyl group.
Examples of Y ₁ in formula (6) include the following (Y-1) to (Y-168).

Y ₁ in the above formula (6) is preferably a highly linear structure from the viewpoint of liquid crystal alignment, and examples thereof include a structure represented by the following formula (8) or the following formula (9).

In the above formulas (8) and (9), A ₁ is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 1 to 20 carbon atoms. A ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1 to 4. When a is 2 or more, the structure of A ₂ may be the same or different. b and c are each independently an integer of 1 to 2.

Specific examples of the above formula (8) and the above formula (9) include Y-7, Y-25, Y-26, Y-27, Y-43, Y-44, Y-45, Y-46, Y -48, Y-71, Y-72, Y-73, Y-74, Y-75, Y-76, Y-82, Y-87, Y-88, Y-89, Y-90, Y-92 Y-93, Y-94, Y-95, Y-96, Y-100, Y-101, Y-102, Y-103, Y-104, Y-105, Y-106, Y-110, Y -111, Y-112, Y-113, Y-115, Y-116, Y-121, Y-122, Y-126, Y-127, Y-128, Y-129, Y-132, Y-134 Y-153, Y-156, Y-157, Y-158, Y-159, Y-160, Y-161, Y-162, Y-163, Y-164 Y-165, Y-166, Y-167, and Y-168 and the like.

Among the other diamines contained in the diamine component for obtaining the polyimide precursor, among others, it is eliminated by heat and generates an amino group, preferably a secondary amino group, represented by the following formula (7). It is preferable that the diamine has a thermally leaving group.

In the above formula (7), D is a thermally detachable group that is preferably eliminated at 150 to 230 ° C., more preferably at 180 to 230 ° C. D is particularly preferably a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group from the viewpoint of elimination temperature.
Specific examples of Y ₁ having a thermally leaving group represented by the above formula (7) include Y-158, Y-159, Y-160, Y-161, Y-162, or Y-163. It is done.
The ratio of the diamine having the structure of the above formula (7) in the total diamine component to be reacted with the tetracarboxylic acid derivative component is preferably 10 to 70 mol%, more preferably 20 to 50 mol%. .

<Tetracarboxylic acid derivative>
The tetracarboxylic acid derivative component for producing the component (A) contained in the liquid crystal aligning agent of the present invention by reacting with a diamine component containing a diamine having the structure of the above formula (1) is a tetracarboxylic acid diester. In addition to anhydrides, tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide can be used. Among these, as the tetracarboxylic acid derivative, tetracarboxylic dianhydride is preferable.

The tetracarboxylic acid derivative preferably has an alicyclic structure, and specific examples of the alicyclic structure include the following formulas (X1-1) to (X1-10).

In formulas (X1-1) to (X1-4), R ₃ to R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, carbon These are 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 more preferably a hydrogen atom or a methyl group.
Specific examples of the structure of formula (X1-1) include the following.

In the present invention, the proportion of the tetracarboxylic acid derivative having an alicyclic structure in the total tetracarboxylic acid derivative component to be reacted with the diamine component is preferably 60 to 100 mol%, more preferably 70 to 100 mol%. Particularly preferred is 80 to 100%.

As the tetracarboxylic acid derivative used in the present invention, those having a structure other than those having the alicyclic structure can be used. Specific examples include those having the structures of the following formulas (X-9) to (X-42).

<Polyimide precursor>
The polyamic acid and polyamic acid ester, which are the precursors of the polyimide contained in the liquid crystal aligning agent of the present invention, are produced as follows by the (polycondensation) reaction of the tetracarboxylic acid derivative component and the diamine component described above. .
<Method for producing polyamic acid>
Specifically, the polyamic acid is obtained by combining tetracarboxylic dianhydride and diamine in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 It can be produced by reacting for ˜12 hours.
The organic solvent used for said reaction will not be specifically limited if the produced | generated polyimide precursor melt | dissolves. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, or 1,3-dimethyl-imidazolidinone Can be mentioned.

When the solubility of the polyamic acid is high, it is represented by methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the following formulas [D-1] to [D-3] A solvent can be used.

In formulas [D-1] to [D-3], D ¹ represents an alkyl group having 1 to 3 carbon atoms, D ² represents an alkyl group having 1 to 3 carbon atoms, and D ³ represents 1 to ³ carbon atoms. 4 represents an alkyl group.
These solvents may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyamic acid, it may be used by mixing with the solvent as long as the produced polyamic acid does not precipitate. Further, since water in the solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyamic acid, it is preferable to use a dehydrated and dried solvent.

The concentration of the polyamic acid is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight product is easily obtained.
The polyamic acid obtained as described above can be recovered by precipitating the polyamic acid by pouring it into a poor solvent while thoroughly stirring the reaction solution. Moreover, the powder of polyamic acid refine | purified by performing precipitation several times, washing | cleaning with a poor solvent, and normal temperature or heat-drying can be obtained. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Method for producing polyamic acid ester>
The polyamic acid ester can be produced by the following method (1), (2) or (3).
(1) When manufacturing from polyamic acid Polyamic acid ester can be manufactured by esterifying the polyamic acid obtained from tetracarboxylic dianhydride and diamine. Specifically, it is produced by reacting a polyamic acid and an esterifying agent in the presence of an organic solvent at −20 ° C. to 150 ° C., preferably 0 to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. it can.

The esterifying agent is preferably one that can be easily removed by purification, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents per 1 mol of the repeating unit.
The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of polymer solubility. These may be used alone or in combination of two or more. Good. The concentration at the time of production is preferably 1 to 30% by mass and more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight product is easily obtained.

(2) When manufactured by reaction of tetracarboxylic acid diester dichloride and diamine The polyamic acid ester can be manufactured from tetracarboxylic acid diester dichloride and diamine.
Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at −20 ° C. to 150 ° C., preferably 0 ° C. to 50 ° C., for 30 minutes to 24 hours, preferably 1 to 4 hours. It can be produced by reacting.
As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds gently. The amount of the base used is preferably 2 to 4 moles relative to the tetracarboxylic acid diester dichloride from the viewpoint that it can be easily removed and a high molecular weight product can be easily obtained.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of the monomer and polymer, and these may be used alone or in combination. The polymer concentration at the time of production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight product is easily obtained. In order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the production of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent mixing of outside air in a nitrogen atmosphere.

(3) When manufacturing from tetracarboxylic-acid diester and diamine Polyamic acid ester can be manufactured by polycondensing tetracarboxylic-acid diester and diamine. Specifically, tetracarboxylic acid diester and diamine in the presence of a condensing agent, a base, and an organic solvent at 0 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., for 30 minutes to 24 hours, preferably 3 to 15 It can manufacture by making it react for time.

Examples of the condensing agent include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triazide. Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N , N ′, N′-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl, and the like. The amount of the condensing agent used is preferably 2 to 3 moles relative to the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the base is preferably 2 to 4 times mol with respect to the diamine component from the viewpoint of easy removal and high molecular weight.
In the above reaction, the reaction proceeds efficiently by adding a Lewis acid. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0 to 1.0 times mol with respect to the diamine component.

Among the methods for producing the three polyamic acid esters, since the high molecular weight polyamic acid ester is obtained, the production method of (1) or (2) is particularly preferable.
The polyamic acid ester solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying. Although a poor solvent is not specifically limited, Water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene etc. are mentioned.

<Production method of polyimide>
The polyimide which is said (A) component can be manufactured by imidating the said polyamic acid or polyamic acid ester. When a polyimide is produced from a polyamic acid ester, chemical imidization in which a basic catalyst is added to a polyamic acid solution obtained by dissolving the polyamic acid ester solution or the polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not easily decrease during the imidization process.

Chemical imidization can be performed by stirring the polyamic acid or polyamic acid ester to be imidized in the presence of a basic catalyst in an organic solvent. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine is preferred because it has sufficient basicity to allow the reaction to proceed.

The temperature for carrying out the imidization reaction is −20 ° C. to 140 ° C., preferably 0 ° C. to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times the polyamic acid or amic acid ester group. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst or the like remains in the solution after the imidation reaction, it is preferable to recover the obtained imidized polymer and redissolve it with an organic solvent to obtain a liquid crystal aligning agent.

The polyimide solution obtained as described above can be polymerized by pouring into a poor solvent while stirring well. Precipitation is performed several times, and after washing with a poor solvent, a purified polyamic acid ester powder can be obtained at room temperature or by heating and drying.
The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

The polyimide which is the component (A) contained in the liquid crystal aligning agent of the present invention is obtained by imidizing the polyimide precursor as described above, and the imidization ratio at that time is 20 to 80%. is required. When the imidization rate is excessively large, the coating property is remarkably deteriorated. On the other hand, when it is excessively small, there is a concern that the hardness of the obtained liquid crystal alignment film cannot be sufficiently obtained. In particular, the imidation ratio is more preferably 50 to 70%.
The molecular weight of the polyimide is preferably 2,000 to 500,000 in terms of weight average molecular weight (Mw), more preferably 5,000 to 300,000, and still more preferably 10,000 to 100,000. . The number average molecular weight (Mn) is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000. .

<(B) component>
The component (B) contained in the liquid crystal aligning agent of the present invention is a compound having two or more crosslinkable functional groups. The crosslinkable functional group is preferably at least one selected from the group consisting of a hydroxyl group, a (meth) acrylate group, a blocked isocyanate group, an oxetane group, and an epoxy group from the viewpoint of availability and effects. Of these, a hydroxyl group is preferred. The compound as the component (B) may have two or more of the same crosslinkable functional groups, or may have two or more different types of crosslinkable functional groups. Although there is no upper limit to the number of crosslinkable functional groups, it is usually 8 or less, preferably 6 or less.

In particular, a preferable compound having two or more hydroxyl groups includes a compound represented by the following formula (2).

In the above formula (2), X ₂ is an n-valent organic group containing an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group. n is an integer of 2 to 6. Any carbon in the aliphatic hydrocarbon group or aromatic hydrocarbon group may be substituted with nitrogen or oxygen.

R ₂ and R ₃ are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, an optionally substituted alkenyl group having 2 to 4 carbon atoms, or An alkynyl group having 2 to 4 carbon atoms which may have a substituent. Further, at least one of R ₂ and R ₃ represents a hydrocarbon group substituted with a hydroxy group.
Among them, atoms directly attached to the carbonyl group of X ₂ in the formula (2) is preferable from the viewpoint of the liquid crystal orientation is a carbon atom, which do not form an aromatic ring. X ₂ in the formula (2) is preferably an aliphatic hydrocarbon group and more preferably 1 to 10 carbon atoms from the viewpoint of liquid crystal alignment and solubility. In the formula (2), n is preferably 2 to 4 from the viewpoint of solubility.

In formula (2), at least one of R ₂ and R ₃ is preferably a structure represented by the following formula (3) from the viewpoint of reactivity, and a structure represented by the following formula (4) More preferably.

In the formula (3), R ₄ to R ₇ are each independently a hydrocarbon group substituted with a hydrogen atom, a hydrocarbon group, or a hydroxy group.

Preferable examples of the compound having two or more hydroxyl-containing groups include the following.

When the component (B) is too much, the liquid crystal orientation and the pretilt angle are affected. Therefore, the content of the component (B) is preferably 0.1 to 20% by mass and more preferably 1 to 10% by mass with respect to the component (A).

<(C) component>
The liquid crystal aligning agent of this invention can contain the polyimide precursor which is a reaction material of a tetracarboxylic-acid derivative component and a diamine component further as (C) component.
As the polyimide precursor of the component (C), the tetracarboxylic acid derivatives and diamines described as the raw material of the polyimide precursor that is the polyimide precursor of the component (A) can be used, but in the same liquid crystal aligning agent The same polyimide precursor as the polyimide precursor of the component (A) contained is excluded. As the polyimide precursor, polyamic acid is preferable.
The liquid crystal aligning agent of this invention can further raise the film | membrane intensity | strength of the liquid crystal aligning film obtained by containing this (C) component. The component (C) in the liquid crystal aligning agent is preferably 20 to 80 mol%, more preferably 40 to 70 mol%, relative to the component (A).

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention has the form of the solution in which the above-mentioned (A) component and (B) component and also (C) component as needed were melt | dissolved in the organic solvent.
The concentration of the polymer in the liquid crystal aligning agent of the present invention can be appropriately changed depending on the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is 1% by mass. From the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. Particularly preferred is 3 to 6.5% by mass.

The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as it uniformly dissolves the contained polymer.
For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone , Cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and the like. In particular, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.
Among the organic solvents contained in the liquid crystal aligning agent of the present invention, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-pentyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, A first consisting of at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N, N-dimethylpropionamide, and 3-butoxy-N, N-dimethylpropionamide Solvent (I),
Butyl cellosolve, butyl cellosolve acetate, 1-butoxy-2-propanol, 2-butoxy-1-propanol, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, diisobutyl carbinol, diisobutyl ketone, propylene carbonate, propylene glycol diacetate And at least one second solvent (II) selected from the group consisting of sopentyl ether.

Furthermore, when the solubility of the polymer of the present invention in a solvent is high, it is preferable to use a solvent represented by the above formula [D-1] to formula [D-3].
The organic solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass of the whole solvent contained in the liquid crystal aligning agent. Of these, 20 to 90% by mass is preferable. More preferred is 30 to 80% by mass.

The liquid crystal aligning agent of this invention can use the solvent (it is also called a poor solvent) which improves the coating property and surface smoothness of a liquid crystal aligning film at the time of apply | coating a liquid crystal aligning agent. Although the specific example of a poor solvent is given to the following, it is not limited to these examples.
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, 1,2- Etanji 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentane Diol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2 Heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1- (Butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate Tar, 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, milk Methyl, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, 3-methoxypropion Ethyl acetate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, lactate n-propyl ester, lactate n-butyl ester, lactic acid Examples thereof include isoamyl esters and solvents represented by the above formulas [D-1] to [D-3].
Of these, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether are preferable.

The poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal aligning agent, more preferably 10 to 80% by mass, and even more preferably 20 to 70% by mass.
In addition to the above, the liquid crystal aligning agent of the present invention includes a polymer other than the polymer described in the present invention, a dielectric or conductive material for changing the electrical properties such as the dielectric constant and conductivity of the liquid crystal alignment film, and liquid crystal Silane coupling agent for the purpose of improving the adhesion between the alignment film 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 the coating film is baked An imidization accelerator for the purpose of efficiently proceeding imidization by heating the body may be added.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is a film obtained by applying the liquid crystal aligning agent to a substrate, drying and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, or a polycarbonate substrate can be used. Further, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed from the viewpoint of simplification of the process. In the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as only one substrate is used. In this case, a material that reflects light, such as aluminum, can be used.

Examples of the method for applying the liquid crystal aligning agent of the present invention include a spin coating method, a printing method, and an ink jet method. Arbitrary temperature and time can be selected for the drying and baking steps after applying the liquid crystal aligning agent of the present invention. Usually, in order to sufficiently remove the contained solvent, it is dried at 50 to 120 ° C., preferably 60 to 100 ° C. for 1 to 10 minutes, preferably 2 to 5 minutes, and then 150 to 300 ° C., preferably Is baked at 200 to 240 ° C. for 5 to 120 minutes, preferably 10 to 30 minutes. The thickness of the coating film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered, so it is 5 to 300 nm, preferably 10 to 200 nm.

Examples of a method for aligning the obtained liquid crystal alignment film include a rubbing method and a photo-alignment processing method.
The rubbing process can be performed using an existing rubbing apparatus. Examples of the material of the rubbing cloth at this time include cotton, nylon, and rayon. As the conditions for rubbing treatment, generally, conditions of a rotational speed of 300 to 2000 rpm, a feed speed of 5 to 100 mm / s, and a pushing amount of 0.1 to 1.0 mm are used. Thereafter, the residue generated by rubbing is removed by ultrasonic cleaning using pure water or alcohol.

As a specific example of the photo-alignment treatment method, the surface of the coating film is irradiated with radiation deflected in a certain direction, and in some cases, a heat treatment is performed at a temperature of 150 to 250 ° C. to impart liquid crystal alignment ability. Is mentioned. As the radiation, ultraviolet rays and visible rays having a wavelength of 100 to 800 nm can be used. Of these, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and ultraviolet rays having a wavelength of 200 to 400 nm are particularly preferable. Further, in order to improve the liquid crystal orientation, radiation may be irradiated while heating the coated substrate at 50 to 250 ° C. Dose of the radiation is preferably 1 ~ 10,000mJ / cm ^2, particularly preferably 100 ~ 5,000mJ / cm ^2. The liquid crystal alignment film produced as described above can stably align liquid crystal molecules in a certain direction.
A higher extinction ratio of polarized ultraviolet light is preferable because higher anisotropy can be imparted. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10: 1 or more, and more preferably 20: 1 or more.
In the above, the film irradiated with polarized radiation may then be contact-treated with a solvent containing at least one selected from the group consisting of water and organic solvents.

The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves a decomposition product generated by light irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Examples include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like. Two or more of these solvents may be used in combination.
In view of versatility and safety, at least one selected from the group consisting of water, 2-propanol, 1-methoxy-2-propanol and ethyl lactate is more preferable. Water, 2-propanol, or a mixed solvent of water and 2-propanol is particularly preferable.

In the present invention, the contact treatment of the film irradiated with polarized radiation and the solution containing the solvent is performed by a method such that the film and the liquid are preferably in sufficient contact with each other, such as immersion treatment or spraying treatment. It is. Among them, a method of immersing in a solution containing a solvent, preferably for 10 seconds to 1 hour, more preferably for 1 to 30 minutes is preferable. The contact treatment may be performed at normal temperature or preferably at 10 to 80 ° C., more preferably at 20 to 50 ° C. Moreover, a means for enhancing contact such as ultrasonic waves can be applied as necessary.
After the contact treatment, in order to remove the solvent in the used solution, rinsing (rinsing) with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, or drying is performed, or both. It's okay.

Furthermore, the film subjected to the contact treatment with the solution containing the solvent may be heated at 150 ° C. or higher for the purpose of drying the solvent and reorienting the molecular chains in the film.
The heating temperature is preferably 150 to 300 ° C. A higher temperature promotes reorientation of molecular chains. However, if the temperature is too high, molecular chains may be decomposed. Therefore, the heating temperature is more preferably 180 to 250 ° C., and particularly preferably 200 to 230 ° C.
If the heating time is too short, there is a possibility that the effect of molecular chain reorientation may not be obtained. If it is too long, the molecular chain may be decomposed, so 10 seconds to 30 minutes is preferable. 1 to 10 minutes is more preferable.

<Liquid crystal display element>
The liquid crystal display element of the present invention comprises the liquid crystal alignment film of the present invention. In the liquid crystal display element of the present invention, after obtaining a substrate with a liquid crystal alignment film from the liquid crystal aligning agent of the present invention by the method for producing a liquid crystal alignment film, a liquid crystal cell is produced by a known method, and a liquid crystal cell is used. This is a display element.
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. Note that an active matrix liquid crystal display element in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting the image display may be used.

First, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes may be ITO electrodes, for example, 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 a sol-gel method.
Next, the liquid crystal alignment film of the present invention is formed on each substrate. Next, the other substrate is superposed on one substrate so that the alignment film surfaces face each other, and the periphery is bonded with a sealant. In order to control the substrate gap, a spacer is usually mixed in the sealing material. In addition, it is preferable that spacers for controlling the substrate gap are also sprayed on the in-plane portion where no sealing material is provided. A part of the sealing material is provided with an opening that can be filled with liquid crystal from the outside.

Next, a liquid crystal material is injected into a space surrounded by two substrates and the sealing material through an opening provided in the sealing material. Thereafter, the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surfaces of the two substrates opposite to the liquid crystal layer. By passing through the above process, the liquid crystal display element of this invention is obtained.
In the present invention, as the sealing agent, for example, a resin having a reactive group such as an epoxy group, an acryloyl group, a (meth) acryloyl group, a hydroxyl group, an allyl group, or an acetyl group, which is cured by ultraviolet irradiation or heating is used. . In particular, it is preferable to use a cured resin system having reactive groups of both an epoxy group and a (meth) acryloyl group.

In the sealing agent of the present invention, an inorganic filler may be blended for the purpose of improving adhesiveness and moisture resistance. The inorganic filler that can be used is not particularly limited. Specifically, spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, sulfuric acid. Barium, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, Examples include asbestos. Preferably, spherical silica, fused silica, crystalline silica, titanium oxide, titanium black, silicon nitride, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, or silicic acid Aluminum is mentioned. Two or more of the above inorganic fillers may be mixed and used.

Examples Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The following are the abbreviations of the compounds and the measurement methods of the respective properties.
NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone,
BCS: Butyl cellosolve,
DA-1: bis (4-aminophenoxy) methane,
DA-2: 1,2-bis (4-aminophenoxy) ethane,
DA-3: N-tert-butoxycarbonyl-N- (2- (4-aminophenyl) ethyl) -N- (4-aminobenzyl) amine,
DA-4: See formula (DA-4) below,
DA-5: 2-tert-butoxycarbonylaminomethyl-p-phenylenediamine (where Boc represents a tert-butoxycarbonyl group),
DA-6: See formula (DA-6) below,
CA-1: See the following formula (CA-1), CA-2: See the following formula (CA-2),
CA-3: See formula (CA-3) below, AD-1: See formula (AD-1) below

[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, cone rotor TE-1 (1 ° 34 ′, R24), and a temperature of 25 ° C.
[Molecular weight]
The molecular weight was measured by a GPC (room temperature gel permeation chromatography) apparatus, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) were calculated as polyethylene glycol and polyethylene oxide equivalent values.
GPC apparatus: manufactured by Shodex (GPC-101), column: manufactured by Shodex (KD803, series of KD805), column temperature: 50 ° C., eluent: N, N-dimethylformamide (as an additive, lithium bromide-water) Japanese (LiBr · H ₂ O) 30 mmol / L, phosphoric acid / anhydrous crystals (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L), flow rate: 1.0 ml / min. Standard samples for use: TSK standard polyethylene oxide (weight average molecular weight (Mw) of about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (peak top molecular weight (Mp) manufactured by Polymer Laboratories) ) About 12,000, 4,000, 1,000). In order to avoid the overlapping of peaks, the measurement was performed by mixing four types of 900,000, 100,000, 12,000, and 1,000, and three types of 150,000, 30,000, and 4,000. Two samples of the mixed sample were measured separately.

<Measurement of imidization ratio>
20 mg of polyimide powder was put into an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixed product) was added to the solution. 53 ml was added and completely dissolved by applying ultrasonic waves. This solution was measured for proton NMR at 500 MHz with an NMR measuring instrument (JNW-ECA500) (manufactured by JEOL Datum). The imidation rate is determined based on protons derived from structures that do not change before and after imidation as reference protons, and the peak integrated value of these protons and proton peaks derived from NH groups of amic acid that appear in the vicinity of 9.5 ppm to 10.0 ppm. It calculated | required by the following formula | equation using the integrated value.
Imidization rate (%) = (1−α · x / y) × 100
In the above formula, x is a proton peak integrated value derived from NH group of amic acid, y is a peak integrated value of reference proton, α is one NH group proton of amic acid in the case of polyamic acid (imidation rate is 0%) Is the number ratio of the reference proton to.

[Production of 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 × 50 mm and a thickness of 0.7 mm. On the substrate, an ITO electrode having a solid pattern constituting a counter electrode as a first layer is formed. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by the CVD method is formed as the second layer. The second layer SiN film has a thickness of 500 nm and functions as an interlayer insulating film. On the second SiN film, a comb-like pixel electrode formed by patterning an ITO film as the third layer is arranged to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of “bow” -shaped electrode elements having a bent central portion. The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. The pixel electrode forming each pixel is formed by arranging a plurality of bent “bow” -shaped electrode elements at the center, so the shape of each pixel is not rectangular but is the same as that of the electrode element. It has a shape that resembles a bold “Kugi” that bends in part. Each pixel is divided into upper and lower portions with a central bent portion as a boundary, and has a first region on the upper side of the bent portion and a second region on the lower side.

When the first region and the second region of each pixel are compared, the formation 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 element of the pixel electrode is formed to form an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode elements of the electrode are formed so as to form an angle of −10 ° (clockwise). As a result, in the first region and the second region of each pixel, the direction of the rotational operation (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode is in the substrate plane. It is comprised so that it may become a mutually reverse direction.

Next, after the liquid crystal aligning agent is filtered through a filter having a pore diameter of 1.0 μm, the prepared substrate with electrodes and a glass substrate having a columnar spacer with a height of 4 μm on which an ITO film is formed on the back surface are spin-coated. It apply | coated by application | coating. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. This coating film surface was irradiated with linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 10: 1 or more via a polarizing plate. This substrate is immersed in at least one solvent selected from water and an organic solvent for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 to 300 ° C. for 5 minutes to provide a substrate with a liquid crystal alignment film Got. The two substrates are combined as a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film faces and the alignment direction is 0 °, and then the sealant is added. An empty cell was produced by curing. 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 drive liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

[Afterimage evaluation by long-term AC drive]
A liquid crystal cell having the same structure as the liquid crystal cell used for the above-described afterimage evaluation was prepared.
Using this liquid crystal cell, 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. Thereafter, 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, the liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, 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. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel became darkest to the angle at which the first region became darkest was calculated as an angle Δ. Similarly, in the second pixel, the second region and the first region were compared to calculate a similar angle Δ.

[Evaluation of pencil hardness]
A sample for pencil hardness evaluation was prepared as follows. A liquid crystal aligning agent was applied to a 30 mm × 40 mm ITO substrate by spin coating. After drying on an 80 ° C. hot plate for 2 minutes, baking was performed in a hot air circulation oven at 230 ° C. for 14 minutes to form a coating film having a thickness of 100 nm. This coating surface was subjected to alignment treatment such as rubbing and polarized ultraviolet irradiation to obtain a substrate with a liquid crystal alignment film. This substrate is immersed in at least one solvent selected from water and an organic solvent for 3 minutes, then immersed in pure water for 1 minute, and heated on a hot plate at 150 ° C. to 300 ° C. for 14 minutes to provide a liquid crystal alignment film A substrate was obtained. The liquid crystal alignment film surface of this substrate was measured by a pencil hardness test method (JIS K5400).

<Synthesis Example 1>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 1.75 g (7.60 mmol) DA-1, 4.64 g (19.0 mmol) DA-2, 3.89 g DA-3 ( 11.4 mmol) was measured, 46.9 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 7.93 g (35.3 mmol) of CA-1 was added, and 36.1 g of NMP was further added so that the solid content concentration was 18% by mass. An acid solution (A) (viscosity: 800 mPa · s) was obtained. It was Mn = 10800 of polyamic acid, and Mw = 23600.
30 g of the polyamic acid solution obtained in a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube was taken, 37.5 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 3.39 g of acetic anhydride and 0.88 g of pyridine were added and heated at 55 ° C. for 3 hours to perform chemical imidization. The obtained reaction solution was added to 270 ml of methanol with stirring, and the deposited precipitate was collected by filtration and subsequently washed with 270 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (A).
The imidation ratio of this polyimide resin powder was 67%, and Mn = 7500 and Mw = 1100.

<Synthesis Example 2>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 was 3.50 g (15.2 mmol), DA-2 was 2.78 g (11.4 mmol), and DA-3 was 3.89 g ( 11.4 mmol) was measured, 46.36 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring the diamine solution, 7.92 g (35.3 mmol) of CA-1 was added, and 36.1 g of NMP was further added so that the solid content concentration was 18% by mass. An acid solution (C) (viscosity: 820 mPa · s) was obtained. It was Mn = 11000 and Mw = 25200 of the polyamic acid.
30 g of the polyamic acid solution obtained in a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube was taken, 37.5 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 3.40 g of acetic anhydride and 0.88 g of pyridine were added and heated at 55 ° C. for 3 hours to perform chemical imidization. The obtained reaction solution was added to 270 ml of methanol with stirring, and the deposited precipitate was collected by filtration and subsequently washed with 270 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (B).
The imidation ratio of this polyimide resin powder was 67%, and Mn = 8000 and Mw = 12,500.

<Synthesis Example 3>
In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 was 0.69 g (3.00 mmol), DA-4 was 1.60 g (5.00 mmol), and DA-3 was 0.68 g ( 2.00 mmol) was measured, 32.3 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 2.17 g (9.70 mmol) of CA-1 was added, 5.00 g of NMP was further added so that the solid content concentration was 18% by mass, and the mixture was stirred at 40 ° C. for 24 hours. An acid solution (C) (viscosity: 790 mPa · s) was obtained. The polyamic acid had Mn = 15500 and Mw = 40600.
50 g of the polyamic acid solution obtained in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube was taken, 62.5 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 5.39 g of acetic anhydride and 1.39 g of pyridine were added and heated at 55 ° C. for 3 hours to perform chemical imidization. The obtained reaction liquid was poured into 525 ml of methanol while stirring, and the deposited precipitate was collected by filtration and subsequently washed with 525 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (C).
The imidation ratio of this polyimide resin powder was 63%, and Mn = 6000 and Mw = 9600.

<Synthesis Example 4>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 6.91 g (30.0 mmol) of DA-1 was measured, 59.1 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 1.50 g (6.00 mmol) of CA-3 was added and stirred at room temperature for 3 hours, and then 6.62 g (22.5 mmol) of CA-2 was added. 12.8 mg of NMP was added so that it might become 15 mass%, and it stirred at room temperature for 24 hours, and obtained the polyamic acid solution (D) (viscosity: 870 mPa * s). The polyamic acid had Mn = 13200 and Mw = 35700.

<Synthesis Example 5>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, weighed 6.33 g (25.9 mmol) of DA-2, 3.79 g (11.1 mmol) of DA-3, and 73.1 g of NMP. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 7.73 g (34.4 mmol) of CA-1 was added, and 8.12 g of NMP was further added so that the solid content concentration was 18% by mass. An acid solution (E) (viscosity: 800 mPa · s) was obtained. It was Mn = 13500 of polyamic acid, and Mw = 23600.
30 g of the polyamic acid solution obtained in a 100 ml four-necked flask with a stirrer and a nitrogen inlet tube was taken, 15.0 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 3.37 g of acetic anhydride and 0.44 g of pyridine were added and heated at 55 ° C. for 3 hours to perform chemical imidization. The obtained reaction solution was poured into 212 ml of methanol while stirring, and the deposited precipitate was collected by filtration and subsequently washed with 212 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (F). The imidation ratio of the polyimide resin was 68%, and Mn = 9400 and Mw = 23000.

<Synthesis Example 6>
In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 4.40 g (18.0 mmol) of DA-2 and 6.15 g (18.0 mmol) of DA-3 were measured, and 74.0 g of NMP was measured. In addition, the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 7.50 g (33.4 mmol) of CA-1 was added, and 8.22 g of NMP was further added so that the solid content concentration was 18% by mass. An acid solution (G) (viscosity: 820 mPa · s) was obtained. It was Mn = 11000 and Mw = 30700 of the polyamic acid.
20 g of the polyamic acid solution (A) obtained in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube was weighed, 14.29 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 1.48 g of acetic anhydride and 0.38 g of pyridine were added and heated at 60 ° C. for 3 hours to perform chemical imidization. The obtained reaction solution was poured into 150 ml of methanol while stirring, and the deposited precipitate was collected by filtration, and subsequently washed with 150 ml of methanol three times. The obtained resin powder was dried at 60 ° C. for 12 hours to obtain a polyimide resin powder (H). The imidation ratio of this polyimide resin powder was 70%, and Mn = 9050 and Mw = 16600.

<Example 1>
Take 1.80 g of the polyimide resin powder (A) obtained in Synthesis Example 1 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP so that the solid content concentration becomes 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (K) was obtained. To this polyimide solution, 0.09 g of AD-1, 11.9 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (1). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 2>
Take 1.80 g of the polyimide resin powder (B) obtained in Synthesis Example 2 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP so that the solid content concentration becomes 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (L) was obtained. To this polyimide solution, 0.09 g of AD-1, 11.9 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (2). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 3>
Take 1.80 g of the polyimide resin powder (C) obtained in Synthesis Example 2 in a 100 ml Erlenmeyer flask, add 22.11 g of NMP so that the solid concentration is 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (M) was obtained. To this polyimide solution, 0.09 g of AD-1, 11.9 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (3). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 4>
7.80 g of 18% by weight polyamic acid (D) and 5.20 g of 15% by weight polyimide solution (K) are placed in a 100 mL Erlenmeyer flask, 0.98 g of AD-1, 4.34 g of NMP, and 5.37 g of GBL. 68 g and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (4). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 5>
7.80 g of 18% by weight polyamic acid (D) and 5.20 g of 15% by weight polyimide solution (L) are placed in a 100 mL Erlenmeyer flask, 0.98 g of AD-1, 4.36 g of NMP, and 5.37 g of GBL. 66 g and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (5). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Comparative Example 1>
Take 1.80 g of the polyimide resin powder (F) obtained in Synthesis Example 5 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP to a solid content concentration of 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (N) was obtained. To this polyimide solution, 0.09 g of AD-1, 11.9 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (6). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Comparative example 2>
Take 1.80 g of the polyimide resin powder (H) obtained in Synthesis Example 6 in a 100 ml Erlenmeyer flask, add 10.2 g of NMP so that the solid content concentration becomes 15%, and stir at 70 ° C. for 24 hours to dissolve. A polyimide solution (O) was obtained. To this polyimide solution, 0.09 g of AD-1, 11.9 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (7). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Comparative Example 3>
To 12 g of the polyimide solution (K) obtained in Example 1, 12.0 g of NMP and 6.00 g of BCS were added and stirred at room temperature for 3 hours to obtain a liquid crystal aligning agent (8). This liquid crystal aligning agent was confirmed to be a uniform solution without any abnormality such as turbidity and precipitation.

<Example 6>
After filtering the liquid crystal aligning agent (1) with a filter having a pore diameter of 1.0 μm, the prepared substrate with electrodes and a glass substrate having a columnar spacer with a height of 4 μm on which an ITO film is formed on the back surface, It applied by spin coat application. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 0.25 J / cm ² of linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 26: 1 through a polarizing plate, and then mixed with a pure water: 2-propanol = 1/1 mixed solution for 5 minutes. The substrate was then immersed for 14 minutes on a 230 ° C. hot plate immersed in pure water for 1 minute to obtain a substrate with a liquid crystal alignment film. It was 3H as a result of measuring the liquid crystal aligning film surface of this board | substrate by the pencil hardness test method (JIS K5400).

<Examples 7 to 10, Comparative Examples 4 to 6>
Samples for a pencil hardness test were prepared in exactly the same manner as in Example 6 except that the liquid crystal aligning agent shown in Table 1 was used instead of the liquid crystal aligning agent (1). The results of the evaluation of each pencil hardness test are shown in Table 1 including the results of Example 6. In Table 1, “H &#60;” represents that the pencil hardness is less than 1.

<Example 12>
After filtering the liquid crystal aligning agent (1) obtained in Example 1 with a filter having a pore size of 1.0 μm, a columnar spacer having a height of 4 μm in which an ITO film is formed on the back surface of the prepared substrate with electrodes is provided. It apply | coated to the glass substrate which has by spin coat application | coating. After drying on an 80 ° C. hot plate for 5 minutes, baking was carried out in a hot air circulating oven at 230 ° C. for 20 minutes to form a coating film having a thickness of 100 nm. The surface of the coating film was irradiated with 0.25 J / cm ² of linearly polarized ultraviolet light having a extinction ratio of 26: 1 and a wavelength of 254 nm through a polarizing plate. This substrate was immersed in pure water for 3 minutes and dried on a hot plate at 230 ° C. for 14 minutes to obtain a substrate with a liquid crystal alignment film.
The above-mentioned two substrates obtained as a set were printed with a sealant on the substrate, and the other substrate was bonded so that the liquid crystal alignment film faced and the alignment direction was 0 °, The agent was cured to produce an empty cell. 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 drive liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 ° C. for 1 hour and left to stand for evaluation of afterimages by long-term AC driving. The value of the angle Δ of this liquid crystal cell after long-term AC driving was 0.10 degrees.

<Examples 12 to 15, Comparative Examples 7 to 9>
Instead of the liquid crystal aligning agent (1), the liquid crystal aligning agent shown in Table 2 was used, respectively, and the irradiation amount of ultraviolet rays was changed to that shown in Table 2 in the same manner as in Example 11. An FFS drive liquid crystal cell was fabricated and afterimage evaluation was performed by long-term alternating current drive. Table 2 shows the value of the angle Δ of the liquid crystal cell after long-term AC driving in each case, including the results of Example 11.

With the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having high film hardness and good afterimage characteristics can be obtained. Therefore, the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention has a high yield in liquid crystal panel production, and can reduce afterimages due to alternating current drive generated in liquid crystal display elements of IPS drive method and FFS drive method, An IPS driving type or FFS driving type liquid crystal display element having excellent afterimage characteristics can be obtained. Therefore, it can be used in a liquid crystal display element that requires high display quality.
It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2016-225395 filed on November 18, 2016 are cited herein as disclosure of the specification of the present invention. Incorporate.

Claims (15)

1. The liquid crystal aligning agent characterized by containing the following (A) component, (B) component, and an organic solvent.
   (A) component: an imidized product of a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative component and a diamine component containing a diamine having the structure of the following formula (1), and an imidization rate of 20% to Polyimide that is 80%.
   

   

   (In the formula, * represents a bond with another atom or group.)
   (B) Component: A compound having two or more crosslinkable functional groups.
2. The liquid crystal aligning agent according to claim 1, wherein the diamine component contains 20 to 50 mol% of a diamine having the structure of the formula (1).
3. The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine component further contains a diamine having a structure in which an amino group is eliminated by heat.
4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the tetracarboxylic acid derivative component has at least one structure selected from the group consisting of:
   

   
5. The crosslinkable functional group is at least one selected from the group consisting of a hydroxyl-containing group, a (meth) acrylate-containing group, a blocked isocyanate-containing group, an oxetane-containing group, and an epoxy-containing group. 2. A liquid crystal aligning agent according to item 1.
6. The liquid crystal aligning agent according to any one of claims 1 to 4, wherein the crosslinkable functional group is a hydroxyl-containing group.
7. The liquid crystal aligning agent according to any one of claims 1 to 6, wherein the compound containing two or more crosslinkable functional groups is represented by the formula (2).
   

   

   (X ₂ is an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an n-valent organic group containing an aromatic hydrocarbon group, and n is an integer of 2 to 6. The above aliphatic hydrocarbon group or aromatic group Any carbon in the group hydrocarbon group may be substituted with nitrogen or oxygen, and R ₂ and R ₃ each independently represents a hydrogen atom or an optionally substituted alkyl having 1 to 4 carbon atoms. A alkenyl group having 2 to 4 carbon atoms or an alkynyl group having 2 to 4 carbon atoms, and at least one of R ₂ and R ₃ represents a hydrocarbon group substituted with a hydroxy group.)
8. Formula (2) in at least one of _{R 2} and _{R 3,} represented by the formula (3), the liquid crystal aligning agent of claim 7.
   

   

   (R ₄ to R ₇ each independently represents a hydrogen atom, a hydrocarbon group, or a hydrocarbon group substituted with a hydroxy group.)
9. The liquid crystal aligning agent according to any one of claims 1 to 8, wherein the compound containing two or more crosslinkable functional groups is a compound represented by the formula (5).
   

   
10. The liquid crystal aligning agent according to any one of claims 1 to 9, wherein the component (B) is contained in an amount of 0.1 to 20% by mass with respect to the component (A).
11. The liquid crystal aligning agent according to any one of claims 1 to 10, further comprising the following component (C):
    Component (C): A polyimide precursor which is a reaction product of a tetracarboxylic acid derivative component and a diamine component (however, the same polyimide precursor as the polyimide precursor of the component (A) is excluded).
12. The organic solvent is N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-pentyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, A first solvent (I) comprising at least one selected from the group consisting of 3-methoxy-N, N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, butyl cellosolve, butyl cellosolve acetate, -Butoxy-2-propanol, 2-butoxy-1-propanol, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, diisobutyl carbinol, diisobutyl ketone, propylene carbonate, propylene glycol diacetate, di The liquid crystal aligning agent according to any one of claims 1 to 11, comprising at least one second solvent (II) selected from the group consisting of isopentyl ethers.
13. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 12.
14. A method for producing a liquid crystal alignment film, wherein the liquid crystal aligning agent according to any one of claims 1 to 12 is applied, baked, and further irradiated with polarized ultraviolet rays.
15. A liquid crystal display element comprising the liquid crystal alignment film according to claim 13.