KR20170056654A - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

(R¹, R² 는, 수소 원자, 탄소수 1 ∼ 4 의 알킬기 또는 식 (2) 의 기이며, 그 적어도 일방은 식 (2) 의 기이다. A 는 단결합 또는 탄소수 1 ∼ 4 의 탄화수소기로 이루어지는 2 가의 기이다)
식 (2)

Provided is a liquid crystal aligning agent which forms a liquid crystal alignment film having good adhesiveness to a sealant and a substrate. A liquid crystal aligning agent comprising a polyimide precursor obtained by reacting a diamine-containing diamine component having a structure represented by the formula (1) with a tetracarboxylic acid component and / or a polyimide obtained by imidizing the polyimide precursor.
Equation (1)

(Wherein R ¹ and R ² are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a group represented by the formula (2), and at least one of them is a group represented by the formula (2): A is a single bond or a hydrocarbon group having 1 to 4 carbon atoms Lt; / RTI >
Equation (2)

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal alignment film, a liquid crystal alignment film, a liquid crystal alignment film, a liquid crystal alignment film,

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element obtained by using a diamine having a specific structure.

At present, a liquid crystal alignment film obtained by applying a liquid crystal aligning agent (also referred to as a liquid crystal alignment treatment agent) containing a polyimide polymer to a substrate and baking is mainly used for the liquid crystal alignment film of the liquid crystal display element.

The liquid crystal alignment film is used for the purpose of controlling the alignment state of the liquid crystal. However, in order to suppress the lowering of the contrast of the liquid crystal display element and the reduction of the afterimage phenomenon accompanying the high definition of the liquid crystal display element, , The residual charge when the direct current voltage is applied is small, and / or the characteristic that the residual charge accumulated by the direct current voltage is relaxed quickly becomes important.

The liquid crystal display element is also known as a lightweight, thin and low power consumption display device. In recent years, even small-sized, high-precision liquid crystal display devices such as mobile phones, smart phones, tablet-type devices and the like, which have rapidly expanded their share, have achieved remarkable progress that requires high display quality.

Particularly, in these small-sized liquid crystal display elements, in order to secure as many display surfaces as possible, so-called frame narrowing is required, in which the width of the sealant used for bonding the substrates of the liquid crystal display element is narrowed have. With the narrowing of the frame of such a panel, the application position of the sealant used in the production of the liquid crystal display element is coated at the position in contact with the end of the liquid crystal alignment film or on the liquid crystal alignment film. However, since the polyimide has no polar group, , Covalent bonds are not formed on the surface of the sealing agent and the liquid crystal alignment film, and adhesion between the substrates becomes insufficient.

In such a case, water may easily enter from the gap between the sealant and the liquid crystal alignment film, particularly in use under high temperature and high humidity conditions, resulting in a problem that display unevenness occurs near the frame around the liquid crystal display element . Therefore, it is a problem to improve the adhesion (adhesion) between the polyimide-based liquid crystal alignment film and the sealant and the substrate. It is required that the improvement of the adhesiveness of the liquid crystal alignment film as described above to the sealant and the substrate is required to be achieved without lowering the liquid crystal alignment property and electric characteristics of the liquid crystal alignment film and further to improve these properties.

Japanese Laid-Open Patent Publication No. 09-278724 Japanese Patent Application Laid-Open No. 10-123532

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device which is free from display unevenness near a frame of a liquid crystal display element, And to provide a novel diamine having a specific structure used in the production of such a liquid crystal aligning agent.

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted intensive investigations in order to achieve the above object and as a result have found that a polyimide precursor using a diamine having a specific structure and / or a liquid crystal aligning agent containing polyimide obtained from the polyimide precursor The present invention has been accomplished on the basis of these findings.

The present invention relates to a liquid crystal aligning agent containing a polyimide precursor obtained by reacting a diamine component and a tetracarboxylic acid component and / or a polyimide obtained from the polyimide precursor, wherein the diamine component is represented by the following formula (1) Structure of the present invention.

[Chemical Formula 1]

( ²⁾ : wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a group represented by the following formula (2), and at least one of them is a group represented by formula (2) , A is a single bond or a divalent group which is a hydrocarbon group having 1 to 4 carbon atoms.)

(2)

The liquid crystal alignment film formed using a liquid crystal aligning agent comprising a polyimide precursor using a novel diamine having a specific structure of the present invention and / or a polyimide obtained from the polyimide precursor can be used as a sealer in a liquid crystal display element, The occurrence of display unevenness near the frame can be suppressed even under high temperature and high humidity conditions, and the frame area around the device can be reduced. Therefore, since the display area can be increased, it can be advantageously used for small-size, high-precision liquid crystal display devices such as cellular phones, smart phones, tablet type devices and the like. In addition, since the residual charge is relaxed quickly, there is an advantage that the afterimage phenomenon of the liquid crystal display element is lost in a short time.

In addition, the polyimide precursor using a diamine having a specific structure of the present invention and / or the polyimide obtained from the polyimide precursor has a solubility in a solvent, and thus has the advantage of obtaining a liquid crystal aligning agent having a high polymer concentration.

[Diamine]

The diamine contained in the diamine component used for obtaining the liquid crystal aligning agent of the present invention is a diamine having a structure represented by the following formula (1) in the molecule.

(3)

[Chemical Formula 4]

In the formulas (1) and (2), R ¹ , R ² and A are as defined above. Among them, R ¹ and R ² are preferably groups represented by formula (2) at least one or both of them, and from the viewpoint of the strength of the alignment film at the time of rubbing, only either one of R ¹ and R ² is represented by formula 2).

A is preferably a single bond. Here, when A is a single bond, the group of the formula (2) is a t-butoxycarbonyl group (also referred to as a Boc group in the present invention).

The diamine having the structure represented by the above formula (1) in the molecule may be any diamine so long as these requirements are satisfied. Preferred examples thereof include diamines represented by the following formula [1].

[Chemical Formula 5]

In the formula [1], R ¹ and R ² are the same as those in the formula (1), including preferable ones. m and n each independently represent an integer of 0 to 3, preferably 0 or 1, and more preferably 1 for ease of obtaining raw materials.

In the formula [1], the amino group (-NH ₂ ) in each benzene ring may be in any position of ortho, meta or para to the bonding position of the alkylene group. However, the ease of synthesis and the polymerization reactivity Position of the meta or para is preferable, and the position of para is more preferable.

Examples of the diamine represented by the formula [1] include the following compounds. In the formulas of the compounds exemplified below, Boc is a group shown below.

[Chemical Formula 6]

(7)

[Chemical Formula 8]

The synthesis method of the diamine represented by the formula [1] is not particularly limited, but general synthesis can be carried out by reducing the dinitro compound X1 of the diamine X as shown below. Further, R _1, R _2, m, n are, respectively, in the above formula ^{(1), R 1, R} 2, the same as m, n.

[Chemical Formula 9]

The reduction reaction includes a hydrogenation reaction in the presence of a catalyst, a reduction reaction carried out under the coexistence of protons, a reduction reaction using formic acid as a hydrogen source, a reduction reaction using hydrazine as a hydrogen source, and the like. You can. Considering the structure of the dinitro compound X1 and the reactivity of the reduction reaction, the hydrogenation reaction is preferable.

The catalyst used in the reduction reaction is preferably an activated carbon bearing metal obtainable as a commercial product, and examples thereof include palladium-activated carbon, platinum-activated carbon and rhodium-activated carbon. Further, it is not always necessary to use a metal catalyst supported on activated carbon, such as palladium hydroxide, platinum oxide, or Raney nickel. In general, palladium-activated carbon widely used is preferable because good results can be obtained.

In order to promote the reduction reaction more effectively, the reaction may be carried out under the coexistence of activated carbon. In this case, the amount of activated carbon to be used is not particularly limited, but is preferably from 1 to 20% by mass, more preferably from 5 to 10% by mass, based on the dinitro compound X1.

For the same reason, the reaction may be carried out under pressure. In this case, in order to avoid reduction of the benzene nucleus, it is carried out in the pressure range up to 20 atm. The reaction is preferably carried out in a range of up to 10 atm.

In the reduction reaction, the use of a solvent is preferable, and any solvent that does not react with each raw material can be used without limitation.

For example, an aprotic polar organic solvent (DMF (N, N-dimethylformamide), DMSO (dimethylsulfoxide), DMAc (dimethylacetamide), NMP (N-methyl- ; Ethers such as Et ₂ O (diethyl ether), i-Pr ₂ O (di isopropyl ether), TBME (methyl tert-butyl ether), CPME (cyclopentyl methyl ether), THF (tetrahydrofuran) Aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetraene, etc., halogenated hydrocarbons such as hexane, heptane, Lower aliphatic acid esters such as methyl acetate, ethyl acetate, butyl acetate and methyl propionate; nitriles such as acetonitrile, propionitrile, butyronitrile and the like; alcohols such as acetonitrile, propionitrile and butyronitrile; Etc. may be used. These solvents may be appropriately selected in consideration of easy occurrence of reaction and the like, and they may be used singly or in combination of two or more. If necessary, the solvent may be dried by using a suitable dehydrating agent or a drying agent to be used as a non-aqueous solvent.

The amount of the solvent to be used (reaction concentration) is not particularly limited, but is 0.1 to 100 times the mass of the dinitro compound X1. Preferably 0.5 to 30 times by mass, and more preferably 1 to 10 times by mass.

The reaction temperature is not particularly limited, but is preferably in the range of -100 ° C to the boiling point of the solvent used, preferably -50 to 150 ° C. The reaction time is usually 0.05 to 350 hours, preferably 0.5 to 100 hours.

On the other hand, the method for synthesizing the dinitro compound X1 is not particularly limited, and can be synthesized by an arbitrary method. As a specific example thereof, the compound X2 and di-tert-butyl dicarbonate are allowed to react in a solvent in the presence of a base, if necessary.

[Chemical formula 10]

It is preferable to use 1 to 5 equivalents, preferably 1.3 to 2.5 equivalents of di-tert-butyl adduct of carboxylate with respect to 1 carboxyl group of the compound X2. By setting the reaction conditions such as the equivalent number of equivalents, Can be controlled.

The presence of the base in the reaction is not necessarily required. However, when a base is used, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate, potassium phosphate, sodium carbonate, potassium carbonate, Amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diisopropylethylamine, pyridine, dimethylaminopyridine, imidazole, quinoline and collidine; Potassium hydroxide, potassium hydroxide, potassium hydroxide, potassium hydroxide, potassium hydroxide, potassium hydroxide, potassium hydroxide, sodium hydroxide, potassium hydroxide,

The solvent in this reaction can be used as long as it is a solvent that does not react with each of the raw materials. It is also possible to use an aprotic polar organic solvent, an ether, an aliphatic hydrocarbon, an aromatic Hydrocarbons, halogenated hydrocarbons, and lower fatty acid esters. These solvents may be appropriately selected in consideration of easy occurrence of reaction and the like, and they may be used singly or in combination of two or more. If necessary, the solvent may be dried by using a suitable dehydrating agent or a drying agent to be used as a non-aqueous solvent.

The amount of the solvent to be used is not particularly limited, but 0.1 to 100 times by mass of the solvent may be used for the dinitro compound X2. Preferably 0.5 to 30 times by mass, and more preferably 1 to 10 times by mass. The reaction temperature is not particularly limited, but is in the range of -100 ° C to the boiling point of the solvent used, preferably in the range of -50 to 150 ° C. The reaction time is usually 0.05 to 200 hours, preferably 0.5 to 100 hours.

The dinitro compound X1 can be synthesized by reacting a carbonyl compound (?) With an amine compound X2 and X2 'having a Boc group as described below in a solvent. Specific examples thereof are shown in the following scheme.

(11)

In the nitro compounds X2 and X2 ', R ¹ and R ² each independently represent hydrogen or a Boc group.

Examples of the carbonyl compound (?) Include phosgene, triphosgene, diphenyl carbonate, bis (nitrophenyl) carbonate, Dimethyl carbonate, diethyl carbonate, ethylene carbonate, 1.1'-carbonylbis-1H-imidazole, methyl chloroformate, benzyl chloroformate, and 4-nitrophenyl chloroformate. Also, carbon oxide may be used instead of the carbonyl compound (?).

The above-mentioned compounds are merely examples, and are not particularly limited.

In order to obtain a compound having a structure symmetrical with respect to the urea group in the above scheme, the nitro compounds X2 and X2 'must be the same. In order to obtain an asymmetric compound, the nitro compound X2 is allowed to equilibrate with respect to the carbonyl compound After the reaction, the nitro compound X2 'having a structure different from that of the nitro compound X2 may be added and reacted. In this case, the introduction order of the amine to which the Boc group is added is not particularly limited.

When a base is used, the addition of a base is not necessarily required. However, when a base is used, an inorganic base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogencarbonate, potassium hydrogen carbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate or cesium carbonate; Amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diisopropylethylamine, pyridine, imidazole, quinoline and collidine; sodium hydride, potassium hydride, tert- , and tert-butoxy potassium; and the like.

The solvent in this reaction can be used as long as it is a solvent that does not react with each of the raw materials. It is also possible to use an aprotic polar organic solvent, an ether, an aliphatic hydrocarbon, an aromatic Hydrocarbons, halogenated hydrocarbons, and lower fatty acid esters. These solvents may be appropriately selected in consideration of easy reaction and the like, and they may be used singly or in combination of two or more. If necessary, the solvent may be dried by using a suitable dehydrating agent or a drying agent to be used as a non-aqueous solvent.

The amount of the solvent to be used (reaction concentration) is not particularly limited, but 0.1 to 100 times by mass of the solvent may be used for the nitro compound X2. Preferably 0.5 to 30 times by mass, and more preferably 1 to 10 times by mass. The reaction temperature is not particularly limited, but is in the range of -100 ° C to the boiling point of the solvent used, preferably in the range of -50 to 150 ° C. The reaction time is usually 0.05 to 200 hours, preferably 0.5 to 100 hours.

In order to synthesize the asymmetric dinitro compound X1 having n different from each other, the isocyanate compound X4 can be synthesized by reacting an isocyanate compound X4 with an amine compound X2 having a Boc group. As a specific example thereof, the following scheme is shown.

[Chemical Formula 12]

In the reaction of the isocyanate compound X4 and the amine compound X2, the amine compound X2 may be used in an amount of 0.98 to 1.2 equivalents to the isocyanate compound X4. More preferably, it is 1.0 to 1.02 equivalents.

Examples of the reaction solvent include, but are not limited to, hydrocarbons such as hexane, cyclohexane, benzene and toluene; halogenated hydrocarbons such as carbon tetrachloride, chloroform and 1,2-dichloroethane; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; nitriles such as acetonitrile and propionitrile; ketones such as ethyl acetate, isopropyl ketone, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone, and the like; Nitrogen-containing aprotic polar solvents; sulfurated aprotic polar solvents such as dimethyl sulfoxide and sulfolane; pyridines such as pyridine and picoline; and the like. These solvents may be used alone, or two or more of them may be mixed and used. Preferably, it is toluene, acetonitrile, or ethyl acetate, more preferably toluene or ethyl acetate.

The amount of the solvent to be used (reaction concentration) is not particularly limited, but the reaction may be carried out without using a solvent. When a solvent is used, 0.1 to 100 times by mass of the solvent is used for the isocyanate compound X4. Preferably 0.5 to 30 times by mass, and more preferably 1 to 10 times by mass.

The reaction temperature is not particularly limited, but is, for example, from -90 to 150 캜, preferably from -30 to 100 캜, more preferably from 0 to 80 캜. The reaction time is usually 0.05 to 200 hours, preferably 0.5 to 100 hours.

A catalyst may be added to shorten the reaction time. Examples thereof include organic tin compounds such as dibutyltin dilaurate, dioctyltin bis (isooctyl thioglycolic acid ester), dibutyltin bis (isooctyl thioglycolic acid ester) and dibutyltin diacetate; , Trimethylamine, tripropylamine, tributylamine, diisopropylethylamine, N, N-dimethylcyclohexylamine, pyridine, tetramethylbutane diamine, N-methylmorpholine, 1,4-diazabicyclo-2.2. Amines such as 2-octane, 1,8-diazabicyclo [5.4.0] undecene, and 1,5-diazabicyclo [4.3.0] nonene-5; p-toluenesulfonic acid, methanesulfonic acid, Organic compounds such as bismuth tris (2-ethylhexanoate) and the like; bismuth compounds such as tetrabutyl titanate, Rapid ammonium salt And the like. These catalysts may be used singly or in combination of two or more. These catalysts are preferably liquid or dissolved in a reaction solvent.

When the catalyst is added, the catalyst is used in an amount of 0.005 to 100 wt% based on the total amount (mass) of the isocyanate compound X4. Preferably 0.05 to 10 wt%, and more preferably 0.1 to 5 wt%. When an organotin compound, a titanium compound, or a bismuth compound is used as the catalyst, it is preferably 0.005 to 0.1 wt%.

[Liquid crystal aligning agent]

The liquid crystal aligning agent of the present invention is a polyimide precursor obtained by reacting a diamine component containing any of diamines represented by the above formula [1] with a tetracarboxylic acid component and / or a polyimide precursor obtained from the polyimide precursor Lt; / RTI >

[Component of tetracarboxylic acid]

Preferable examples of the tetracarboxylic acid component are represented by any one of the following formulas [8] to [10].

[Chemical Formula 13]

Among the above tetracarboxylic acid derivatives, a polyamic acid is obtained by reacting a tetracarboxylic acid anhydride represented by the formula [8] with a diamine. The polyamic acid ester can be obtained by reacting a tetracarboxylic acid diester dichloride represented by the formula [9] or a tetracarboxylic acid diester represented by the formula [10] with a diamine.

The polyimide can be synthesized by imidizing such a polyamic acid or a polyamic acid ester.

In the formulas [9] and [10], R ⁶ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a 2-propyl group, a butyl group and a t-butyl group. In general, the polyamic acid ester has a higher temperature at which the imidization proceeds as the number of carbon atoms of the alkyl group having the polyamic acid ester increases. Therefore, the alkyl group is preferably a methyl group or an ethyl group in view of easiness of imidization by heat, and a methyl group is particularly preferable.

In the formulas [8] to [10], X is preferably a tetravalent hydrocarbon group having an alicyclic or aromatic ring structure of 4 to 6 ring atoms. Specific preferred examples of X include (X-1) to (X-46) shown below.

[Chemical Formula 14]

[Chemical Formula 15]

[Chemical Formula 16]

[Chemical Formula 17]

[Other diamines]

When the polyimide precursor contained in the liquid crystal aligning agent of the present invention is obtained, other diamine represented by the following formula [11] may be used in combination with the specific diamine as the diamine component .

[Chemical Formula 18]

H ₂ NY-NH ₂ [11]

In the formula [11], Y is a divalent group consisting of a hydrocarbon, preferably a group having a structure of an alicyclic or aromatic ring of 6-membered rings. Examples of (Y-1) to (Y-97) are given as preferred specific examples of Y,

[Chemical Formula 19]

[Chemical Formula 20]

[Chemical Formula 21]

[Chemical Formula 22]

(23)

≪ EMI ID =

(25)

(26)

(27)

(28)

[Chemical Formula 29]

(30)

[Synthesis of polyimide precursor 1 (polyamic acid)

Polyamic acid (hereinafter, also referred to as a polymer) can be synthesized by a moderate reaction of a tetracarboxylic acid dianhydride and a diamine (hereinafter also referred to as a monomer).

(31)

Specifically, the tetracarboxylic acid dianhydride and the diamine are reacted in the presence of an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 12 hours Can be synthesized.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in the solubility of the monomer and the polymer obtained. Two or more kinds may be mixed and used. The concentration of the polymer in the reaction system is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass, from the standpoint that precipitation of the polymer hardly occurs and high molecular weight substances are easily obtained.

The polyamic acid thus obtained can be recovered by precipitating a polymer by injecting the reaction solution into a poor solvent while stirring well. It is also possible to obtain a purified polyamic acid powder by conducting precipitation several times, washing with a poor solvent, and then drying at room temperature or by heating. Examples of the poor solvent include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

[Synthesis of polyimide precursor 2 (polyamic acid ester)] [

The polyamic acid ester can be synthesized by any of the following methods (A) to (C).

(A) When polyamic acid ester is synthesized from polyamic acid

The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from a tetracarboxylic acid dianhydride and a diamine.

(32)

Concretely, the polyamic acid and the esterifying agent are synthesized by reacting in the presence of an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 4 hours .

As the esterifying agent, those which can be easily removed by purification are preferable, and N, N-dimethylformamide dimethylacetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N , N-dimethylformamide dineopentylbutylacetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazine, Propyl-3-p-tolyltriazole, and the like. The amount of the esterifying agent to be added is preferably 2 to 6 molar equivalents relative to 1 mol of the repeating unit of the polyamic acid. The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or gamma -butyrolactone in the solubility of the polymer, May be mixed and used. The concentration at the time of synthesis is preferably from 1 to 30 mass%, more preferably from 5 to 20 mass%, since precipitation of the polymer is difficult to occur and a high molecular weight material is easily obtained.

(B) When a polyamic acid ester is synthesized from a tetracarboxylic acid diester dichloride and a diamine

The polyamic acid ester can be synthesized by the reaction of a tetracarboxylic acid diester dichloride with a diamine.

(33)

Specifically, the tetracarboxylic acid diester dichloride and the diamine are reacted in the presence of a base and an organic solvent at -20 to 150 ° C, preferably 0 to 50 ° C for 30 minutes to 24 hours, For 4 hours.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable for the reaction to proceed mildly. The amount of the base to be added is preferably 2 to 4 times the amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

As the organic solvent to be used in the above reaction, N-methyl-2-pyrrolidone,? -Butyrolactone and the like are preferable in terms of the solubility of the monomer and the polymer, and they may be used alone or in combination of two or more . The concentration at the time of the synthesis is preferably from 1 to 30 mass%, more preferably from 5 to 20 mass%, from the viewpoint that the precipitation of the polymer is hardly caused and the high molecular weight material is easily obtained.

In order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and the reaction is preferably carried out in a nitrogen atmosphere to prevent the introduction of external air desirable.

(C) When a polyamic acid is synthesized from a tetracarboxylic acid diester and a diamine

The polyamic acid ester can be synthesized by polycondensation of a tetracarboxylic acid diester and a diamine with a condensing agent.

(34)

Specifically, the tetracarboxylic acid diester and diamine are reacted in the presence of a condensing agent, a base and an organic solvent at 0 to 150 ° C, preferably 0 to 100 ° C, for 30 minutes to 24 hours, preferably 3 To < / RTI > 15 hours.

Examples of the condensing agent include triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3- dimethylaminopropyl) carbodiimide hydrochloride, N, N'-carbonyldiimidazole, dimethoxy- (Benzotriazol-1-yl) -N, N, N ', N'-tetramethyluronium tetrafluoroborate, O- (benzotriazol- (2,3-dihydro-2-thioxo-3-benzoxazolyl) diphenylphosphonate, and the like can be used. have. The amount of the condensing agent to be added is preferably 2 to 3 times the mole of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be added is preferably 2 to 4 times the amount of the diamine component in view of easy removal and high molecular weight.

In addition, in the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. 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 the molar amount of the diamine component.

Among the methods for synthesizing the above three polyamic acid esters, the synthesis method of (A) and (B) is particularly preferable because a polyamic acid ester having a high molecular weight can be obtained.

The solution of the polyamic acid ester thus obtained can be precipitated by pouring into a poor solvent while stirring well. After the precipitation is repeated several times, it is washed with a poor solvent and then heated or dried at room temperature to obtain a purified polyamic acid ester powder. Examples of the poor solvent include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

[Molecular weight of polyimide precursor]

The molecular weight of the polyimide precursor affects the viscosity of the varnish and the physical strength of the polyimide film. The weight average molecular weight is preferably 500,000 or less in view of obtaining a good coating workability of the varnish and a good uniformity of the coating film. In view of obtaining a polyimide film having sufficient strength, 2,000 or more is preferable, 300,000, and more preferably 5,000 to 100,000. The molecular weight of the polyimide precursor can be controlled by adjusting the ratio of the diamine component and the tetracarboxylic acid derivative used in the polymerization reaction. As this ratio, a molar ratio of 1: 0.7 to 1.2 can be exemplified. The closer the molar ratio is to 1: 1, the larger the molecular weight of the polyimide precursor is.

[Synthesis of polyimide]

The polyimide of the present invention can be synthesized by imidizing the polyimide precursor. A simple and preferable method for synthesizing a polyimide from a polyimide precursor is chemical imidization in which a catalyst is added to a solution of the polyamic acid obtained by the reaction of a diamine component and a tetracarboxylic dianhydride and is subjected to an imidation reaction at a relatively low temperature And the molecular weight of the polymer is unlikely to decrease in the process of imidization.

The chemical imidization can be carried out by stirring the polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the above-mentioned polymerization reaction may be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like. Among them, pyridine is preferable since it has a suitable basicity for promoting the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Above all, use of acetic anhydride is preferable since purification after completion of the reaction becomes easy.

The temperature at which the imidization reaction is carried out is -20 to 200 占 폚, preferably 0 to 180 占 폚, and the reaction time is 1 to 100 hours, preferably 1 to 8 hours. The amount of the basic catalyst is 0.5 to 30 molar equivalents, preferably 2 to 20 molar equivalents, and the amount of the acid anhydride is 1 to 50 molar equivalents, preferably 3 to 30 molar equivalents, of the amic acid group. The imidization rate of the resulting polymer can be controlled by controlling the amount of catalyst, temperature, reaction time, and the like. Since the added catalyst remains in the solution after the imidization reaction, it is preferable that the imidized polymer obtained is recovered by the means described below and redissolved in an organic solvent to give the liquid crystal aligning agent of the present invention.

The solution of the polyimide obtained by the above method can be precipitated by injecting into a poor solvent while stirring well. The precipitated polyimide powder can be obtained by conducting precipitation several times, washing with a poor solvent, and then drying at room temperature or by heating. Examples of the poor solvent include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene, although the solvent is not particularly limited so long as it allows the polymer to be precipitated.

[Liquid crystal aligning agent]

The liquid crystal aligning agent of the present invention is a varnish-phase solution containing the polyimide precursor and / or polyimide (hereinafter also referred to as a polymer component) obtained as described above. The liquid crystal aligning agent of the present invention may contain two or more kinds of polyimide precursors, two or more types of polyimide, or both polyimide precursors and polyimide. Further, the liquid crystal aligning agent may contain the polyimide precursor of the present invention or a polymer other than the polyimide of the present invention.

The simplest constitutional examples of the liquid crystal aligning agent of the present invention include a composition comprising the polymer component of the polyimide precursor and / or polyimide and an organic solvent for dissolving the polymer component. The composition may be the reaction solution itself when a polyimide precursor or polyimide is synthesized, or the reaction solution may be diluted with a solvent described below. When the polyimide precursor or polyimide is recovered as a powder, it may be dissolved in an organic solvent to form a polymer solution.

When the polyimide precursor or polyimide powder is dissolved in an organic solvent, the concentration of the polymer component is preferably from 10 to 30 mass%, particularly preferably from 10 to 15 mass%. Further, they may be heated when they are dissolved. The heating temperature is preferably 20 to 150 占 폚, particularly preferably 20 to 80 占 폚.

The organic solvent for dissolving the polyimide precursor or polyimide is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples of the solvent include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl- -Methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethylsulfoxide, dimethylsulfone, gamma -butyrolactone, 1,3-dimethyl- imidazolidinone, N, N-dimethylpropanamide, and the like. These may be used alone or in combination of two or more. Insofar as the solvent alone can not dissolve the polymer component uniformly, it may be mixed with the organic solvent as long as the polymer is not precipitated.

The solvent component of the liquid crystal aligning agent of the present invention may contain, in addition to the organic solvent for dissolving the polymer component, a solvent for improving the film uniformity when the liquid crystal aligning agent is applied to the substrate. As such a solvent, a solvent having a lower surface tension than that of the organic solvent is generally used. Specific examples thereof include ethylcellosolve, butylcellosolve, ethylcarbitol, butylcarbitol, ethylcarbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy- Propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether Propyl alcohol, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, and the like. have. These solvents may be used in combination of two or more.

The concentration of the polymer in the liquid crystal aligning agent of the present invention can be appropriately changed according to the thickness of the liquid crystal alignment film to be formed, but is preferably 1% by mass or more from the viewpoint of forming a uniform and defect- By mass or less. The polymer concentration is more preferably 2 to 8% by mass.

The liquid crystal aligning agent of the present invention may contain various additives such as a silane coupling agent and a crosslinking agent.

The silane coupling agent is added for the purpose of improving the adhesion between the substrate on which the liquid crystal aligning agent is formed and the liquid crystal alignment film formed thereon. Specific examples of the silane coupling agent include those described in International Patent Application Publication No. WO2010 / 050523 (International Application No. PCT / JP2009 / 068523), paragraph 1 (0164) to the last row).

The amount of the silane coupling agent to be used is preferably from 0.01 to 5% by mass, more preferably from 0.1 to 1% by mass, based on the polymer component, from the viewpoint that unreacted does not adversely affect liquid crystal alignability, Do. In the case of adding a silane coupling agent, it is preferable to add a silane coupling agent before the addition of a solvent for improving the film uniformity in order to prevent precipitation of the polymer.

[Liquid Crystal Alignment Layer]

The coating film obtained by applying the liquid crystal aligning agent of the present invention to a substrate, drying and firing, and if necessary, this coating film surface is subjected to orientation treatment already known. The substrate to which the liquid crystal aligning agent is applied is not specifically limited as long as it is a substrate having high transparency and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. It is preferable to use a substrate in terms of simplifying the process. In the reflection type liquid crystal display element, if it is only a substrate on one side, it may be opaque such as a silicon wafer, and a material that reflects light such as aluminum may be used as the electrode.

Examples of the application method of the liquid crystal aligning agent include a spin coating method, a printing method, and an ink jet method. The drying and firing steps after application of the liquid crystal aligning agent can be carried out at arbitrary temperature and time. Usually, it is dried at 50 to 120 ° C for 1 to 10 minutes and then at 150 to 300 ° C for 5 to 120 minutes in order to sufficiently remove the contained organic solvent.

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 deteriorate. Therefore, it is 5 to 300 nm, preferably 10 to 200 nm. When the liquid crystal is horizontally oriented or tilted, the coated film after firing is subjected to rubbing or photo-alignment treatment.

[Liquid crystal display element]

After obtaining a substrate on which a liquid crystal alignment film is formed from the liquid crystal aligning agent of the present invention, a liquid crystal cell is prepared by a known method to obtain a liquid crystal display element.

The manufacturing method of the liquid crystal cell is not particularly limited. For example, a pair of substrates on which a liquid crystal alignment film is formed is preferably 1 to 30 占 퐉, more preferably 2 to 10 占 퐉 A spacer is interposed therebetween, the periphery is fixed with a sealant, and a liquid crystal is injected and sealed. The method of sealing the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which a liquid crystal cell is produced under reduced pressure, a liquid crystal is injected, a dropping method in which a liquid crystal is dropped and then encapsulation is performed.

As another method for manufacturing a liquid crystal cell, there is a method in which a liquid crystal aligning agent is applied on two substrates to form a liquid crystal alignment layer, two substrates are arranged so that the liquid crystal alignment layers face each other, A method in which a liquid crystal layer is sandwiched and ultraviolet rays are irradiated while an electric field is applied to the liquid crystal layer. The substrate to be used is not particularly limited as long as it is a substrate having high transparency. Normally, a substrate on which a transparent electrode for driving the liquid crystal is formed on a substrate and on which an electrode pattern or a projection pattern is formed may be used. If a line / slit electrode pattern of 1 to 10 mu m is formed on one side substrate of a liquid crystal cell and a slit pattern or a projection pattern is not formed on the opposite substrate, the process at the time of manufacturing can be simplified, Transmittance can be obtained.

The liquid crystal alignment layer is a resin film for aligning the liquid crystal. The method of forming the liquid crystal alignment layer on the substrate using the liquid crystal aligning agent is not particularly limited as long as the method described in the liquid crystal alignment film described above and the firing method after application Can be applied.

The step of irradiating ultraviolet light while applying an electric field to the liquid crystal layer includes a method of applying an electric field to a liquid crystal layer by applying a voltage between electrodes provided on the substrate and irradiating ultraviolet light while maintaining the electric field . Here, the voltage applied between the electrodes is, for example, 5 to 30 Vp-p, preferably 5 to 20 Vp-p. The dose of the ultraviolet rays is, for example, 1 to 60 J, preferably 40 J or less. As the ultraviolet rays are less, the lowering of the reliability, which is the cause of the destruction of the members constituting the liquid crystal display element, can be suppressed and the ultraviolet ray irradiation time can be selected.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not construed as being limited thereto. The abbreviations, analysis methods, analysis conditions, and methods of characterization of the used compounds are as follows.

NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve

DMAP: Dimethylaminopyridine

Boc2O: di-tert-butyl < / RTI >

DMAP: Dimethylaminopyridine Pd / C: palladium carbon

DIEPA: Diisopropylethylamine

DMF: Dimethylformamide

THF: tetrahydrofuran

(35)

( ¹ H-NMR measurement)

Apparatus: Varian NMR system 400 NB (400 MHz) (Varian), and JMTC-500/54 / SS (500 MHz)

Measurement solvent: CDCl ₃ (deuterated chloroform), DMSO-d ₆ (deuterated dimethylsulfoxide)

Reference material: TMS (tetramethylsilane) (?: 0.0 ppm, ¹ H) and CDCl ₃ (?: 77.0 ppm, ¹³ C)

(Molecular Weight Measurement of Polyimide Precursor and Imidized Polymer)

(GPC) apparatus (GPC-101) (manufactured by Showa Denko K.K.) and column (KD-803, KD-805) (Shodex) at room temperature.

Column temperature: 50 ° C

30 mmol / L of lithium bromide-hydrate (LiBr.H ₂ O), 30 mmol / L of phosphoric acid / anhydrous crystal (o-phosphoric acid) as the additive, N, N'-dimethylformamide Furan (THF) of 10 ml / l)

Flow rate: 1.0 ml / min

Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000 and 30,000) (manufactured by Toso Co., Ltd.) and polyethylene glycol (molecular weight: about 12,000, 4,000 and 1,000) by Polymer Laboratories.

≪ Synthesis of diamine (A1) >

(36)

The dinitro compound B (100 g, 279 mmol) and 1,2-dichloroethane (700 g) were charged into a one liter (four liter) flask and the temperature was raised to 85 deg. g, 2.8 mmol), Boc2O (103 g, 474 mmol) and 1,2-dichloroethane (300 g) were added dropwise over 30 minutes and the mixture was stirred for 2 hours. After completion of the reaction was confirmed by HPLC (high performance liquid chromatography), the solution was concentrated under reduced pressure to 350 g, followed by addition of 2-propanol (600 g), followed by cooling to 5 캜 and stirring for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (200 g) and dried to obtain powder crystals A1-1 (yield: 120 g, yield: 94%).

A mixture of A1-1 (100 g, 218 mmol), 5 mass% Pd / C (50% aqueous solution) and toluene (1200 ml) was stirred for 5 hours at 60 deg. After completion of the reaction, the catalyst was filtered, and the solution was cooled to 5 캜 and further stirred for 1 hour. The precipitated crystals were filtered off under reduced pressure, washed with toluene (200 g) and dried to obtain powder crystals A1 (yield 70 g, yield 80%).

≪ Synthesis of diamine (A2) >

(37)

DIEPA (21.3 g, 165 mmol) and DMAP (1.83 g, 15 mmol) were added to a DMF solution (269 g) of dinitro derivative B (53.8 g, 150 mmol) in a 1 L Boc2O (32.7 g, 150 mmol) was added dropwise at room temperature over 30 minutes. After stirring at room temperature for 2 hours, DIEPA (21.3 g, 165 mmol) and Boc2O (32.7 g, 165 mol) were added, and the mixture was stirred at room temperature for 24 hours. Then DIEPA (21.3 g, 165 mmol) and Boc2O (32.7 g, 150 mmol) were further added and the mixture was stirred at room temperature for 18 hours. The obtained reaction solution was diluted with ethyl acetate (1078 g) and then washed three times with 10 mass% NaCl aqueous solution (1000 g). Thereafter, the organic layer was dried over magnesium sulfate and concentrated. The obtained crude product was subjected to column chromatography using ethyl acetate and hexane (1: 3 by volume ratio, the same applies hereinafter), to obtain dinitro acid A2- 1 (yield: 17.7 g, yield: 21%).

5% by mass Pd / C (50% aqueous solution) (1.71 g, 10 wt%) was added to a THF solution (88.5 g) of Dinitroza A2-1 (17.7 g, 31.7 mmol) And the mixture was stirred at room temperature for 24 hours. Subsequently, filtration was performed by a membrane filter to remove Pd / C, and the filtrate was concentrated to obtain an amorphous product. The obtained amorphous substance was subjected to column chromatography using ethyl acetate and hexane (volume ratio 2: 3) to obtain diamine A2 (yield: 12.2 g, yield: 77%).

[Synthesis Example 1]

DA-1 (0.42 g, 2.8 mmol) and DA-3 (1.67 g, 4.2 mmol) were weighed into a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 21.7 g of NMP was added, And dissolved with stirring while nitrogen was supplied. While stirring the diamine solution, CA-1 (0.534 g, 2.45 mmol) and CA-2 (0.837 g, 4.27 mmol) were added, and further 5.4 g of NMP was added. Thereafter, the mixture was stirred for 3 hours to obtain a polyamic acid solution having a resin solid content concentration of 12 mass%. The viscosity of this polyamic acid solution at 25 캜 was verified by an E-type viscometer (manufactured by Toki Industries Co., Ltd.) and found to be 320 mPa.. The molecular weight of the polyamic acid was Mn = 10,550 and Mw = 32,000.

[Synthesis Example 2]

DA-1 (0.42 g, 2.8 mmol) and DA-4 (2.09 g, 4.2 mmol) were weighed into a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 21.7 g of NMP was added, And dissolved with stirring while nitrogen was supplied. While stirring the diamine solution, CA-1 (0.534 g, 2.45 mmol) and CA-2 (0.837 g, 4.27 mmol) were added, and further 5.4 g of NMP was added. Thereafter, the mixture was stirred for 3 hours to obtain a polyamic acid solution having a resin solid content concentration of 12 mass%. The viscosity of this polyamic acid solution at 25 캜 was found to be 370 mPa 확인 by an E-type viscometer (manufactured by Toki Industries Co., Ltd.). The polyamic acid had an Mn of 19,000 and an Mw of 50,500.

[Comparative Synthesis Example 1]

DA-1 (0.42 g, 2.8 mmol) and DA-2 (1.25 g, 4.2 mmol) were weighed into a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 21.7 g of NMP was added, And dissolved with stirring while nitrogen was supplied. While stirring the diamine solution, CA-1 (0.534 g, 2.45 mmol) and CA-2 (0.837 g, 4.27 mmol) were added, and further 5.4 g of NMP was added. Thereafter, the mixture was stirred for 3 hours to obtain a polyamic acid solution having a resin solid content concentration of 12 mass%. The viscosity of the polyamic acid solution at 25 占 폚 was determined by an E-type viscometer (manufactured by Toki Industries Co., Ltd.), and found to be 330 mPa 占 퐏. The molecular weight of the polyamic acid was Mn = 9,900 and Mw = 21,800.

[Example 1]

5.65 g of NMP, 1.0 g of an NMP solution containing 1.0% by mass of 3-glycidoxypropyltriethoxysilane, and 5.55 g of BCS were added to 10.0 g of the polyamic acid solution obtained in Synthesis Example 1, % Of liquid crystal aligning agent (A-1). This liquid crystal aligning agent (A-1) was found to be a homogeneous solution because no abnormality such as turbidity or occurrence of precipitates was observed.

[Example 2]

5.65 g of NMP, 1.0 g of an NMP solution containing 1.0 mass% of 3-glycidoxypropyltriethoxysilane, and 5.55 g of BCS were added to 10.0 g of the polyamic acid solution obtained in Synthesis Example 2, % Of liquid crystal aligning agent (A-2). No abnormality such as generation of turbidity or precipitates was observed in the liquid crystal aligning agent (A-2), and it was confirmed that the solution was a homogeneous solution.

[Comparative Example 1]

5.65 g of NMP, 1.0 g of an NMP solution containing 1.0% by mass of 3-glycidoxypropyltriethoxysilane, and 5.55 g of BCS were added to 10.0 g of the polyamic acid solution obtained in Comparative Synthesis Example 1, % Of liquid crystal aligning agent (B-1). No abnormality such as generation of turbidity or precipitates was observed in the liquid crystal aligning agent (B-1), and it was confirmed that the solution was a homogeneous solution.

≪ Solubility in? -Butyrolactone >

To the stirred solution of the obtained liquid crystal aligning agent (5.0 g), the solubility was evaluated by adding γ-butyl lactone (GBL) while recording the amount of the solvent until the solid was precipitated.

Table 1 shows the results of the amounts of GBL added to the liquid crystal aligning agents A-1, A-2, and B-1.

≪ Production of Adhesion Evaluation Sample >

The liquid crystal aligning agent was filtered with a filter of 1.0 mu m and then spin-coated on a glass substrate on which a transparent electrode was formed. The substrate was dried on a hot plate at 80 DEG C for 2 minutes and then baked at 230 DEG C for 20 minutes. Thereby obtaining a coated film. Two substrates thus obtained were prepared, and a bead spacer having a diameter of 4 mu m was dispersed on the surface of the liquid crystal alignment film of one of the substrates, followed by coating with a sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) . Subsequently, the liquid crystal alignment film surface of the other substrate was inwardly laminated such that the overlapping width of the substrate was 1 cm, and the sealant was positioned at the center of the overlapping portion of the substrates. At that time, the amount of the sealant was adjusted so that the diameter of the sealant after the fusion was about 3 mm. Two assembled substrates were fixed with a clip and then thermally cured at 120 DEG C for 1 hour to prepare a sample for evaluation of adhesion.

<Measurement of Adhesive Force>

(N) at the time of peeling off is obtained by fixing the end of the upper and lower substrates with a tabletop type precision universal testing machine (AGS-X500N) manufactured by Shimadzu Corporation, .

The value obtained by dividing the pressure (N) by the area (mm 2) estimated from the diameter of the measured sealant and standardizing it was used as an index of the adhesive force.

Table 2 shows the results of the adhesion of the liquid crystal aligning agents A-1 and B-1.

&Lt; Production of liquid crystal cell &

The liquid crystal aligning agent was filtered with a filter of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode formed thereon. The substrate was dried on a hot plate at 80 캜 for 2 minutes and then baked at 230 캜 for 20 minutes, Thereby obtaining a coated film. This imidated polymer film was subjected to ultrasonic irradiation in pure water for one minute after rubbing with a rayon bath (roll diameter 120 mm, rotation speed 1000 rpm, moving speed 20 mm / sec, indentation amount 0.4 mm) Lt; 0 &gt; C for 10 minutes. Two substrates each having the liquid crystal alignment film thus obtained were prepared, spacers having a size of 4 mu m were provided on the liquid crystal alignment film surface of one of the substrates, and the rubbing directions of the two substrates were anti-parallel. And the periphery was sealed, and an empty cell having a cell gap of 4 탆 was produced. A liquid crystal (MLC-2041, manufactured by Merck) was vacuum-injected into the cell at room temperature and the injection port was sealed to obtain an anti-parallel liquid crystal cell.

<Liquid crystal alignment property>

The alignment state of the liquid crystal cell was observed with a polarizing microscope, and those with no alignment defects were determined as &quot; good &quot; and those with alignment defects were determined as &quot; defective. &Quot; Table 3 shows the evaluation results of the orientations of the liquid crystal aligning agents A-1, A-2 and B-1.

&Lt; Fabrication of Liquid Crystal Cell for Evaluation of Electrical Properties &

A liquid crystal cell having a structure of a liquid crystal display element of FFS (Fringe Field Switching) system was produced.

First, a substrate on which an electrode was formed was prepared. The substrate is a glass substrate having a size of 30 mm x 35 mm and a thickness of 0.7 mm. IZO (Indium Tin Oxide) having a beta-pattern constituting the counter electrode as the first layer is formed on the substrate. Electrodes were formed. On the first layer counter electrode, a SiN (silicon nitride) film formed by CVD (Chemical Vapor Deposition) method was formed as the second layer. The thickness of the second-layer SiN film is 500 nm and functions as an interlayer insulating film. On the second-layer SiN film, a comb-shaped pixel electrode formed by patterning the IZO film as the third layer is disposed, and two pixels, i.e., the first pixel and the second pixel, are formed. The size of each pixel is 10 mm in length and 5 mm in width. At this time, the first layer counter electrode and the third layer pixel electrode were electrically insulated by the action of the second layer SiN film.

The third-layer pixel electrode has a comb-like shape formed by arranging a plurality of elongated electrode elements bent at a central portion. The width of each electrode element in the short direction was 3 mu m and the gap between the electrode elements was 6 mu m. Since the pixel electrode forming each pixel is constituted by arranging a plurality of electrode elements bent in a central portion in the shape of a letter, the shape of each pixel is not rectangular, It had a shape resembling the character of the letter. Each pixel has a first region on the upper side and a second region on the lower side of the bent portion, which are vertically divided with the central bent portion as a boundary.

When the first region and the second region of each pixel are compared with each other, the electrode elements of the pixel electrodes constituting the first region and the second region are different from each other. That is, when the rubbing direction of a liquid crystal alignment film, which will be described below, is taken as a reference, the electrode elements of the pixel electrode are formed so as to form an angle of +10 degrees (clockwise direction) in the first region of the pixel, Is formed so as to form an angle (clockwise direction) of -10 degrees. That is, in the first region and the second region of each pixel, the direction of the rotation operation (inflation / switching) of the liquid crystal caused by the application of the voltage between the pixel electrode and the counter electrode is opposite to each other Consists of.

Next, the obtained liquid crystal aligning agent was filtered with a filter of 1.0 탆, and then applied to the substrate on which the prepared electrode was formed by spin coat coating. After drying for 120 seconds on a hot plate at 80 DEG C, firing was carried out in a far infrared oven at 230 DEG C for 20 minutes to obtain a polyimide film having a film thickness of 60 nm. This polyimide membrane was rubbed into a rayon bath (roller diameter: 120 mm, roller rotation speed: 500 rpm, moving speed: 30 mm / sec, indentation length: 0.3 mm, rubbing direction: 10 ° with respect to the third layer IZO comb electrode) Direction), the substrate was cleaned by ultrasonic irradiation for 1 minute with pure water, water droplets were removed by air blowing, and then dried at 80 DEG C for 15 minutes to obtain a substrate having a liquid crystal alignment film formed thereon. As a counter substrate, a polyimide film was formed in the same manner as described above on a glass substrate having columnar spacers having a height of 4 占 퐉 in which ITO electrodes were formed on the back surface. In the same manner as described above, A substrate having an alignment film formed thereon was obtained. One set of substrates on which these two liquid crystal alignment films were formed was printed with a sealant in the form of leaving a liquid crystal injection hole on the substrate and the other liquid crystal alignment film face was facing and the rubbing direction was antiparallel Then, the sealing agent was cured to prepare an empty cell having a cell gap of 4 탆. A liquid crystal MLC-2041 (manufactured by Merck & Co., Inc.) was injected into the empty cell by a vacuum injection method and the injection port was sealed to obtain an FFS type liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 110 DEG C for 30 minutes, allowed to stand at 23 DEG C for one night, and then used for evaluation.

&Lt; Relaxation characteristics of accumulated residual charges &gt;

The liquid crystal cell (normally using liquid crystal) was provided between two polarizing plates arranged so that the polarization axis thereof was orthogonal to each other. In the state where the pixel electrode and the opposite electrode were short-circuited, The backlight was irradiated and the angle of the liquid crystal cell was adjusted so that the luminance of the LED backlight transmitted light measured on the two polarizing plates was minimized.

Next, V-T characteristics (voltage-transmittance characteristics) under a temperature of 23 캜 were measured while applying a rectangular wave having a frequency of 30 Hz to this liquid crystal cell, and an AC voltage having a relative transmittance of 23% was calculated. This AC voltage corresponds to a region where a change in luminance with respect to a voltage is large, and therefore, it is suitable for evaluating the residual charge through the luminance.

Next, a rectangular wave having a relative transmittance of 23% and a rectangular wave having a frequency of 30 Hz was applied for 5 minutes, and then a DC voltage of +1.0 V was superimposed and driven for 30 minutes. Thereafter, the dc voltage was cut off, and again a rectangular wave having a relative transmittance of 23% and a frequency of 30 Hz was applied for 30 minutes.

The faster the relaxation of the accumulated charge is, the faster the accumulation of charges on the liquid crystal cell is when the direct current voltage is superimposed, and the relaxation property of the accumulated charge is shorter in the state where the relative transmittance immediately after superimposing the direct current voltage is 40% %. &Lt; / RTI &gt; It was defined that the shorter the time, the better the relaxation characteristics of the accumulated charge, and the evaluation was carried out. Table 4 shows the relaxation characteristics of the liquid crystal aligning agents A-1 and B-1.

Industrial availability

The liquid crystal aligning agent of the present invention can form a liquid crystal alignment film having good adhesiveness to the sealant and the substrate in the element and can provide a large display area with few display irregularities in the vicinity of the frame, , A smart phone, a tablet type terminal, and the like.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2014-190292 filed on September 18, 2014 are incorporated herein by reference and are hereby incorporated by reference.

Claims (11)

A liquid crystal aligning agent comprising a polyimide precursor obtained by reacting a diamine component and a tetracarboxylic acid component and / or a polyimide obtained from the polyimide precursor, wherein the diamine component is a diamine having a structure represented by the following formula (1) Wherein the liquid crystal aligning agent is a liquid crystal aligning agent.
[Chemical Formula 1]

( ²⁾ : wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a group represented by the following formula (2), and at least one of them is a group represented by formula (2) , A is a single bond or a divalent group which is a hydrocarbon group having 1 to 4 carbon atoms.)
(2)

The method according to claim 1,
Wherein the diamine is a diamine represented by the following formula [1].
(3)

(R ¹ , R ² and A are the same as those in the formulas (1) and (2), and m and n are each independently 0 to 3.) 3. The method according to claim 1 or 2,
A liquid crystal aligning agent comprising the diamine represented by the above formula [1] in an amount of 5 to 100 mol% of the diamine component. 4. The method according to any one of claims 1 to 3,
Wherein the total content of the polyimide precursor and the polyimide is 1 to 20% by weight. 5. The method according to any one of claims 2 to 4,
Wherein the substitution position of the amino group in the benzene ring of the diamine represented by the formula [1] is a meta position or a para position with respect to the bonding position of the alkylene group. A diamine represented by the following formula [1].
[Chemical Formula 4]

(Wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a group represented by the following formula (2), and at least one of them is a group represented by formula (2) Independently, 0 to 3. In the formula (2), A is a single bond or a divalent group which is a hydrocarbon group having 1 to 4 carbon atoms.)
[Chemical Formula 5]

The method according to claim 6,
A diamine in which the NH ₂ group in the benzene ring is in the meta position or the para position with respect to the bonding position of the alkylene group. The method according to claim 6,
Diamine, any one of the following diamines:
[Chemical Formula 6]

(7)

(Provided that Boc is a group represented by the following formula)
[Chemical Formula 8]

A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 5. 10. The method of claim 9,
Wherein the film has a thickness of 5 to 500 nm. 10. A liquid crystal display element in which the substrate having the liquid crystal alignment film according to claim 9 or 10 is a glass substrate or a plastic substrate.