KR102430123B1 - Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display element - Google Patents

Abstract

A liquid crystal aligning agent contains the organic solvent containing the at least 1 sort(s) of polymer chosen from the group which consists of a polyimide and a polyimide precursor, and the solvent of following (A) group and (B) group, It is characterized by the above-mentioned.
(A) group: at least one solvent selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone
(B) group: at least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol

Description

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

This invention relates to the liquid crystal aligning agent suitable for application|coating by the inkjet method, the liquid crystal aligning film obtained from this liquid crystal aligning agent, and a liquid crystal display element.

As a liquid crystal aligning film, the so-called polyimide-based liquid crystal aligning film in which a liquid crystal aligning agent containing a polyimide precursor such as polyamic acid or a solution of a soluble polyimide as a main component is applied and baked is widely used. In general, spin coating, dip coating, flexographic printing, and the like are known. In practice, there are many applications by flexographic printing. In addition, in flexographic printing, various resin plates are required due to differences in the types of liquid crystal panels, the plate exchange is complicated in the manufacturing process, film formation on a dummy substrate to stabilize the film formation process, and plate production Since there exists a problem, such as becoming a factor of an increase in the manufacturing cost of this liquid crystal display panel, the application|coating by the inkjet method (henceforth inkjet application|coating) attracts attention in recent years.

It is calculated|required that the film-thickness nonuniformity inside a coated surface is small from the influence on display uniformity and an electrical property, and the film-forming precision of the application|coating peripheral part is high as for the liquid crystal aligning film formed by various application|coating methods. In particular, if there is a film thickness nonuniformity, a difference may occur in display quality due to the nonuniformity, which may be a major cause of the occurrence of a display defect. In addition, the total amount of ionic impurities that may be generated from the film may also be a major factor affecting the alignment film.

It is preferable that application|coating nonuniformity does not generate|occur|produce easily in the solvent contained in an aligning agent from the above reason, and it is possible to apply|coat uniformly.

In order to improve the film-forming precision of the application|coating periphery, the method of confining an alignment film in a predetermined range by a structure is proposed (patent document 1, patent document 2, patent document 3). However, these methods have the drawback that additional structures are required.

Japanese Laid-Open Patent Publication No. 2004-361623 Japanese Patent Laid-Open No. 2008-145461 Japanese Patent Laid-Open No. 2010-281925

Then, this invention can form the coating film excellent in the uniformity of the film thickness in a coating surface, and the linearity of the application|coating periphery, and it aims at providing the polyimide-type liquid crystal aligning agent excellent in the electrical property of a liquid crystal display element. do.

MEANS TO SOLVE THE PROBLEM This inventor has reached|attained this invention which makes the following summary as a result of repeating research in order to achieve the said objective.

A first aspect of the present invention that achieves the above object contains at least one polymer selected from the group consisting of polyimides and polyimide precursors, and a solvent containing the solvents of groups (A) and (B) below. It exists in the liquid crystal aligning agent characterized by the above-mentioned.

(A) group: at least one solvent selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone

(B) group: at least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol

A second aspect of the present invention that achieves the above object is characterized in that the solvent of group (A) contains at least one selected from the group consisting of N-methylpyrrolidone and γ-butyrolactone. It exists in the liquid crystal aligning agent of a 1st aspect.

A third aspect of the present invention that achieves the above object is characterized in that the solvent of group (A) is 50 wt% to 95 wt% with respect to the total solvent amount, the liquid crystal alignment of the first aspect or the second aspect is on the

A fourth aspect of the present invention that achieves the above object is any one of the first to third aspects, characterized in that the solvent of group (B) is 5% to 50% by weight based on the total amount of solvent. of liquid crystal aligning agent.

The 5th aspect of this invention which achieves the said objective contains the said polymer 1 mass % - 5 mass %, It exists in the liquid crystal aligning agent in any one of the 1st aspect thru|or 4th aspect characterized by the above-mentioned.

The 6th aspect of this invention which achieves the said objective contains 95 mass % - 99 mass % of the said solvent, It exists in the liquid crystal aligning agent in any one of the 1st aspect thru|or 5th aspect characterized by the above-mentioned.

The 7th aspect of this invention which achieves the said objective exists in the liquid crystal aligning film characterized by the above-mentioned obtained from the liquid crystal aligning agent in any one of a 1st aspect - a 6th aspect.

The 8th aspect of this invention which achieves the said objective is provided with the liquid crystal aligning film of a 7th aspect, It exists in the liquid crystal display element characterized by the above-mentioned.

When the liquid crystal aligning agent of this invention applies inkjet application|coating especially, the coating film excellent in the linearity of the application|coating periphery is obtained. Moreover, the liquid crystal aligning film obtained from the liquid crystal aligning agent of this invention is excellent in a voltage retention characteristic.

The liquid crystal aligning agent of this invention contains the organic solvent containing the at least 1 sort(s) of polymer chosen from the group which consists of a polyimide and a polyimide precursor, and the following (A) group and (B) group solvent, It is characterized by the above-mentioned do. Hereinafter, the liquid crystal aligning agent of this invention is demonstrated in detail.

<Organic solvent>

The organic solvent containing the solvent of the following (A) group and following (B) group is contained in the liquid crystal aligning agent of this invention.

(A) Group: At least one solvent selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone.

(B) Group: At least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol.

<Solvent of group (A)>

The solvent of group (A) contained in the organic solvent of the present invention is at least one solvent selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone. . These are mainly solvents for dissolving a polymer. Especially, it is preferable that it is at least 1 sort(s) chosen from the group which consists of N-methylpyrrolidone and (gamma)-butyrolactone from a soluble viewpoint.

As for content of the solvent of the said (A) group, it is preferable from a solubility viewpoint of an aligning agent that it is 50 weight% - 95 weight% with respect to the total amount of solvents.

<solvent of group (B)>

The solvent of group (B) contained in the organic solvent of the present invention is selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol at least one solvent. These are mainly solvents for providing favorable applicability|paintability.

It is preferable from a viewpoint of stability of a solution that content of the solvent of the said (B) group is 5 weight% - 50 weight% with respect to the total solvent amount.

<Other solvents>

The liquid crystal aligning agent of this invention is a grade which exhibits the effect of this invention. WHEREIN: It can contain solvents other than said solvent (henceforth another solvent). Examples of other solvents are listed below, but are not limited thereto.

For example, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-ethyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone , N-vinyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, ethyl cellosolve, butyl Cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 2-part Toxy-1-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate , Butyl cellosolve acetate, dipropylene glycol, 2-(2-ethoxypropoxy) propanol, lactic acid methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, di Acetone alcohol etc. are mentioned.

The combination of the solvent preferable as another solvent, and the solvent with which the combination with the said (A) group and the said (B) group is preferable is illustrated below.

For example, N,N-dimethylformamide, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diisobutyl carbinol, diisopropyl ether, diisobutyl ketone, ethylene glycol, 1 -Methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 2-butoxy-1-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene Glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, butyl cellosolve acetate, dipropylene glycol, dipropylene glycol dimethyl ether, dipropylene glycol dimethyl -n-propyl ether etc. are mentioned.

<Polymer>

The polymer contained in the liquid crystal aligning agent of this invention is an at least 1 sort(s) of polymer chosen from the group which consists of a polyimide and a polyimide precursor.

A polyimide precursor can be represented by the following formula (1).

[Formula 1]

In said formula (1), X< ₁ > is a tetravalent organic group derived from a tetracarboxylic-acid derivative, Y< ₁ > is a divalent organic group derived from diamine, R< ₁ > is a hydrogen atom or a C1-C5 organic group. represents alkylene. From a viewpoint of the easiness of advancing of the imidation reaction at the time of heating, a hydrogen atom, a methyl group, and an ethyl group are preferable, and, as for R< ₁ >, a hydrogen atom or a methyl group is more preferable.

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. From a viewpoint of liquid-crystal orientation, A ₁ and A ₂ have a preferable hydrogen atom or a methyl group.

Hereinafter, each component used as a raw material constituting the polymer will be described in detail.

<Diamine>

The structure of the diamine component used for the liquid crystal aligning agent of this invention is not specifically limited.

The diamine used for superposition|polymerization of the polymer which has the structure of the said Formula (1) can be generalized by the following Formula (2).

[Formula 2]

A ₁ and A ₂ of the formula (2) have the same definitions as A ₁ and A ₂ of the formula (1) including preferred examples. When the structure of Y ₁ is illustrated, it is as follows.

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

[Formula 19]

[Formula 20]

[Formula 21]

In said formula (Y-165) and said formula (Y-166), n is an integer of 1-6.

[Formula 22]

Boc in the formulas (Y-175), (Y-176), (Y-179) and (Y-180) represents a tert-butoxycarbonyl group.

<Tetracarboxylic acid derivative>

As a tetracarboxylic-acid derivative component for manufacturing the polymer which has the structural unit of the said Formula (1) contained in the liquid crystal aligning agent of this invention, it is not only tetracarboxylic dianhydride but the tetracarboxylic-acid derivative A tetracarboxylic acid, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, or a tetracarboxylic acid dialkyl ester dihalide compound can also be used.

It is more preferable to use at least 1 selected from tetracarboxylic dianhydride or its derivative(s) represented by following formula (3) as tetracarboxylic dianhydride or its derivative(s).

[Formula 23]

In said formula (3), X< ₁ > is a tetravalent organic group which has an alicyclic structure, The structure is not specifically limited. As a specific example, a following formula (X1-1) - a following formula (X1-44) are mentioned.

[Formula 24]

In the 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, They are a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, or a phenyl group, and may be same or different. From a viewpoint of liquid-crystal orientation, a hydrogen atom, a halogen atom, a methyl group, or an ethyl group is preferable, and, as for R3 _{- R23} , a hydrogen atom or a methyl group is more preferable. As a specific structure of the said Formula (X1-1), the structure represented by a following formula (X1-1-1) - a following formula (X1-1-6) is mentioned. From a viewpoint of the liquid-crystal orientation and the sensitivity of a photoreaction, a following formula (X1-1-1) is especially preferable.

[Formula 25]

[Formula 26]

[Formula 27]

[Formula 28]

[Formula 29]

[Formula 30]

<The manufacturing method of polyamic acid ester>

The polyamic acid ester which is one of the polyimide precursors used for this invention is compoundable by the method of (1), (2), or (3) shown below.

(1) When synthesizing from polyamic acid

Polyamic acid ester is compoundable by esterifying the polyamic acid obtained from tetracarboxylic dianhydride and diamine.

Specifically, a polyamic acid and an esterification agent are -20 degreeC - 150 degreeC in presence of an organic solvent, Preferably in 0 degreeC - 50 degreeC, it is 30 minutes - 24 hours, Preferably it is making it react for 1 hour - 4 hours can be synthesized by

The esterifying agent is preferably one that can be easily removed by purification, and includes N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamidedineopentylbutylacetal, N,N-dimethylformamidedi-t-butylacetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazine , 1-propyl-3-p-tolyltriazine, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, and the like. As for the addition amount of an esterification agent, 2 molar equivalent - 6 molar equivalent are preferable with respect to 1 mol of repeating units of a polyamic acid.

The solvent used for the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the viewpoint of polymer solubility, and these are one type or two or more types. You may mix and use it. From a viewpoint that polymer precipitation does not occur easily and a high molecular weight body is easy to obtain, 1 mass % - 30 mass % are preferable, and, as for the density|concentration at the time of a synthesis|combination, 5 mass % - 20 mass % are more preferable.

(2) When synthesized by reaction of tetracarboxylic acid diester dichloride and diamine

Polyamic acid ester is compoundable from tetracarboxylic-acid diester dichloride and diamine.

Specifically, tetracarboxylic-acid diester dichloride and diamine are -20 degreeC - 150 degreeC in presence of a base and an organic solvent, Preferably it is 0 degreeC - 50 degreeC WHEREIN: 30 minutes - 24 hours, Preferably 1 hour It can synthesize|combine by making it react for - 4 hours.

Although pyridine, triethylamine, 4-dimethylaminopyridine, etc. can be used for the said base, pyridine is preferable since reaction advances mildly. It is preferable that the addition amount of a base is a quantity with easy removal, and it is 2 times mole - 4 times mole with respect to tetracarboxylic-acid diester dichloride from a viewpoint that a high molecular weight body is easy to be obtained.

As for the solvent used for said reaction, N-methyl-2-pyrrolidone or (gamma)-butyrolactone is preferable from the solubility of a monomer and a polymer, and these may be used 1 type or in mixture of 2 or more types. From a viewpoint that polymer precipitation does not occur easily and a high molecular weight body is easy to obtain, 1 mass % - 30 mass % are preferable, and, as for the polymer concentration at the time of synthesis, 5 mass % - 20 mass % are more preferable. Moreover, in order to prevent hydrolysis of tetracarboxylic-acid diester dichloride, it is preferable that the solvent used for the synthesis|combination of polyamic acid ester is dehydrated as much as possible, and it is preferable to prevent mixing of external air in nitrogen atmosphere.

(3) When synthesizing polyamic acid ester from tetracarboxylic acid diester and diamine

Polyamic acid ester is compoundable by polycondensing tetracarboxylic-acid diester and diamine.

Specifically, tetracarboxylic-acid diester and diamine are 0 degreeC - 150 degreeC in presence of a condensing agent, a base, and an organic solvent, Preferably it is 0 degreeC - 100 degreeC WHEREIN: 30 minutes - 24 hours, Preferably 3 It can synthesize|combine by making it react for time - 15 hours.

Examples of the condensing agent include triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1 ,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluroniumtetrafluoroborate, O-(benzotriazole- 1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, (2,3-dihydro-2-thioxo-3-benzooxazolyl)phosphonic acid diphenyl, etc. may be used. can As for the addition amount of a condensing agent, 2 times mole - 3 times mole are preferable with respect to tetracarboxylic-acid diester.

Tertiary amines, such as a pyridine and triethylamine, can be used for the said base. The addition amount of a base is a quantity which is easy to remove, and 2 times mole - 4 times mole are preferable with respect to a diamine component from a viewpoint that a high molecular weight body is easy to obtain.

Moreover, in the said reaction, reaction advances efficiently by adding a Lewis acid as an additive. As a Lewis acid, lithium halides, such as lithium chloride and lithium bromide, are preferable. As for the addition amount of a Lewis acid, 0 times mole - 1.0 times mole are preferable with respect to a diamine component.

Since high molecular weight polyamic acid ester is obtained among the synthesis|combining method of said three types of polyamic acid ester, the synthesis method of said (1) or said (2) is especially preferable.

A polymer can be deposited by injecting|pouring into a poor solvent, stirring well the solution of polyamic acid ester obtained by making it above. Precipitation is performed several times, and after washing|cleaning with a poor solvent, the powder of polyamic acid ester refined by normal temperature or heat-drying can be obtained. Although the poor solvent is not specifically limited, Water, methanol, ethanol, hexane, a butyl cellosolve, acetone, toluene, etc. are mentioned.

<Method for producing polyamic acid>

The polyamic acid which is a polyimide precursor used for this invention is compoundable by the method shown below.

Specifically, tetracarboxylic dianhydride and diamine are -20 degreeC - 150 degreeC in presence of an organic solvent, Preferably in 0 degreeC - 50 degreeC, it is 30 minutes - 24 hours, Preferably it is 1 hour - 12 hours It can synthesize|combine by making it react.

The organic solvent used for the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the viewpoint of monomer and polymer solubility, and these are one type or two. You may mix and use more than a kind. From a viewpoint that polymer precipitation does not occur easily and a high molecular weight body is easy to obtain, 1 mass % - 30 mass % are preferable, and, as for the density|concentration of a polymer, 5 mass % - 20 mass % are more preferable.

The polyamic acid obtained as mentioned above can precipitate and collect|recover a polymer by inject|pouring into a poor solvent, stirring a reaction solution well. Moreover, after performing precipitation several times and washing|cleaning with a poor solvent, the powder of the refined polyamic acid can be obtained by normal temperature or heat-drying. Although the poor solvent is not specifically limited, Water, methanol, ethanol, hexane, a butyl cellosolve, acetone, toluene, etc. are mentioned.

<Manufacturing method of polyimide>

The polyimide used for this invention can be manufactured by imidating the said polyamic acid ester or polyamic acid. When manufacturing a polyimide from polyamic acid ester, chemical imidation which adds a basic catalyst to the polyamic acid solution obtained by dissolving the said polyamic acid ester solution or polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferable because the imidation reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not decrease easily during the imidization process.

Chemical imidation can be performed by stirring polyamic acid ester to be imidated in basic catalyst presence in an organic solvent. As the organic solvent, a solvent used in the polymerization reaction described above may be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, triethylamine is preferable because it has sufficient basicity to advance the reaction.

The temperature at the time of imidation reaction is -20 degreeC - 140 degreeC, Preferably it is 0 degreeC - 100 degreeC, and can carry out reaction time in 1 hour - 100 hours. The quantity of a basic catalyst is 0.5 mol times - 30 mol times of an amic acid ester group, Preferably they are 2 mol times - 20 mol times. The imidation rate of the polymer obtained is controllable by adjusting a catalyst amount, temperature, and reaction time. Since the added catalyst etc. remain|survive in the solution after imidation reaction, it is preferable to collect|recover the obtained imidation polymer by the means mentioned below, to melt|dissolve again in an organic solvent, and to set it as the liquid crystal aligning agent of this invention.

When manufacturing a polyimide from a polyamic acid, chemical imidation which adds a catalyst to the solution of the said polyamic acid obtained by reaction of a diamine component and tetracarboxylic dianhydride is simple. Chemical imidization is preferable because the imidation reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not decrease easily during the imidization process.

Chemical imidation can be performed by stirring the polymer to be imidated in presence of a basic catalyst and an acid anhydride in an organic solvent. As the organic solvent, a solvent used in the polymerization reaction described above may be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a suitable basicity for advancing the reaction. Moreover, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. are mentioned as an acid anhydride, Especially, since purification after completion|finish of reaction becomes easy when acetic anhydride is used especially, it is preferable.

The temperature at the time of imidation reaction is -20 degreeC - 140 degreeC, Preferably it is 0 degreeC - 100 degreeC, and can carry out reaction time in 1 hour - 100 hours. The amount of the basic catalyst is 0.5 to 30 moles of the amic acid group, preferably 2 to 20 moles, and the amount of the acid anhydride is 1 to 50 moles of the amic acid group, preferably 3 to 30 moles. it's a boat The imidation rate of the polymer obtained is controllable by adjusting a catalyst amount, temperature, and reaction time.

Since the catalyst etc. added remain in the solution after imidation reaction of polyamic acid ester or polyamic acid, the obtained imidation polymer is collect|recovered by the means described below, it melt|dissolves again in an organic solvent, and is liquid crystal of this invention It is preferable to set it as an aligning agent.

A polymer can be deposited by injecting|pouring into a poor solvent, stirring well the solution of the polyimide obtained by making it above. Precipitation is performed several times, and after washing|cleaning with a poor solvent, the powder of polyamic acid ester refined by normal temperature or heat-drying can be obtained.

Although the said poor solvent is not specifically limited, Methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, etc. are mentioned.

<Liquid crystal aligning agent>

The liquid crystal aligning agent used for this invention has the form of the solution which the polymer of a specific structure melt|dissolved in the organic solvent. As for the molecular weight of the polyimide precursor and polyimide of this invention, 2,000-500,000 are preferable at a weight average molecular weight, More preferably, it is 5,000-300,000, More preferably, it is 10,000-100,000. Moreover, the number average molecular weight becomes like this. Preferably it is 1,000-250,000, More preferably, it is 2,500-150,000, More preferably, it is 5,000-50,000.

Although the density|concentration of the polymer of the liquid crystal aligning agent used for this invention can be suitably changed according to thickness setting of the coating film to be formed, it is preferable that it is 1 weight% or more from the point of forming a uniform and defect-free coating film, and the solution It is preferable to set it as 10 weight% or less from the point of storage stability.

The liquid crystal aligning agent of this invention may contain various additives, such as a silane coupling agent and a crosslinking agent. A silane coupling agent is added in order to improve the adhesiveness of the board|substrate to which a liquid crystal aligning agent is apply|coated, and the liquid crystal aligning film formed there. A conventional silane coupling agent is added.

When the amount of the silane coupling agent added is too large, unreacted ones may adversely affect the liquid crystal orientation, and when too small, the effect on adhesiveness is not exhibited. and 0.1 wt% to 1.0 wt% are more preferable. When adding the said silane coupling agent, in order to prevent polymer precipitation, it is preferable to add before adding the solvent for improving the said coating-film uniformity.

Moreover, in order to advance imidation of a polyimide precursor efficiently, when baking a coating film, you may add an imidation accelerator to the liquid crystal aligning agent of this invention. As the imidation accelerator, an existing one is used.

When adding an imidation accelerator, since imidation may advance by heating, it is preferable to add after diluting with a good solvent and a poor solvent.

<Liquid crystal alignment film>

The liquid crystal aligning film of this invention is a film|membrane obtained by apply|coating the said liquid crystal aligning agent to a board|substrate, drying and baking. The substrate on which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate with high transparency, and plastic substrates such as glass substrates, silicon nitride substrates, acrylic substrates, and polycarbonate substrates can be used, and ITO electrodes for driving liquid crystals It is preferable from a viewpoint of simplification of a process to use the board|substrate on which the back was formed. In the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used only on one side of the substrate, and a material that reflects light such as aluminum can also be used for the electrode in this case.

As a coating method of the liquid crystal aligning agent of this invention, although the spin coat method, the printing method, etc. can also be used, As mentioned above, especially the liquid crystal aligning agent of this invention is especially suitable for the inkjet method. When the liquid crystal aligning agent of this invention is apply|coated by the inkjet method and a coating film is formed (inkjet application|coating), the coating film excellent in the uniformity of the film thickness in an application surface, and the linearity of an application|coating periphery is obtained.

The drying after apply|coating the liquid crystal aligning agent of this invention, and a baking process can select arbitrary temperature and time. Usually, in order to fully remove the organic solvent to contain, it is made to dry at 50 degreeC - 120 degreeC for 1 minute - 10 minutes, and it bakes at 150 degreeC - 300 degreeC after that for 5 minutes - 120 minutes. Although the thickness of the coating film after baking is not specifically limited, Since reliability of a liquid crystal display element may fall when too thin, it is 5 nm - 300 nm, Preferably they are 10 nm - 200 nm.

After apply|coating and baking the liquid-crystal aligning agent of this invention on a board|substrate, it can orientation-process by a rubbing process, a photo-alignment process, etc., or can use it as a liquid crystal aligning film without an orientation process in a vertical orientation use etc.

<Liquid crystal display element>

After the liquid crystal display element of this invention obtains the board|substrate with a liquid crystal aligning film from the liquid crystal aligning agent of this invention by said method, and orientation-processes, a liquid crystal cell is manufactured by a well-known method, and it was set as the liquid crystal display element .

Although the manufacturing method of a liquid crystal cell is not specifically limited, If an example is given, it turns into a liquid crystal aligning film surface inside a pair of board|substrate with a liquid crystal aligning film, Preferably it is 1 micrometer - 30 micrometers, More preferably, it is 2 micrometers - 10 After inserting a micrometer spacer between and installing, the periphery is fixed with a sealing compound, and the method of injecting and sealing a liquid crystal is common. The method of sealing a liquid crystal is not specifically limited, The vacuum method which injects a liquid crystal after making the inside of the produced liquid crystal cell reduced pressure, the dripping method of encapsulating after dripping a liquid crystal, etc. can be illustrated.

Example

The present invention will be further specifically described below by way of examples. However, it goes without saying that the present invention is not limited to these Examples.

In addition, the symbol used by an Example and a comparative example, and the measuring method of each characteristic are as follows.

1,3DMCBDA: 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride

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

DA-1: diamine of the following formula DA-1

DA-2: diamine of the following formula DA-2

DA-3: diamine of the following formula DA-3

[Formula 31]

Boc in the formulas DA-2 and DA-3 represents a tert-butoxycarbonyl group.

<solvent>

NMP: N-methyl-2-pyrrolidone

BCS : Butyl Cellosolve

GBL: γ-butyrolactone

BCA: Butyl Cellosolve Acetate

PB: propylene glycol monobutyl ether

DME: dipropylene glycol dimethyl ether

DEDG: Diethylene glycol diethyl ether

DAA: diacetone alcohol

4M4M2P: 4-methoxy-4-methyl-2-pentanone

4H2B: 4-hydroxy-2-butanone

2M2H: 2-methyl-2-hexanol

<Viscosity>

In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Industries, Ltd.) at a sample amount of 1.1 ml, cone rotor TE-1 (1°34', R24), and a temperature of 25°C. did.

<Molecular Weight>

In the synthesis example, the molecular weight of the polymer is measured by a GPC (room temperature gel permeation chromatography) apparatus, and a number average molecular weight (hereinafter also referred to as Mn) and a weight average molecular weight (hereinafter also referred to as Mw) in terms of polyethylene glycol and polyethylene oxide ) was calculated.

GPC device: manufactured by Shodex (GPC-101)

Column: manufactured by Shodex (KD803, KD805 series)

Column temperature: 50℃

Eluent: N,N-dimethylformamide (as an additive, lithium bromide-hydrate (LiBr·H ₂ O) is 30 mmol/L, phosphoric acid/anhydrous crystals (o-phosphoric acid) is 30 mmol/L, tetrahydrofuran (THF) ) is 10 ml/L)

Flow rate: 1.0 ml/min

Standard sample for calibration curve preparation: TSK standard polyethylene oxide (weight average molecular weight (Mw) about 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol manufactured by Polymer Laboratories (peak top molecular weight (Mp) about 12,000, 4,000, 1,000). In the measurement, in order to avoid overlapping peaks, two samples of a sample in which four kinds of 900,000, 100,000, 12,000, and 1,000 were mixed, and a sample in which three kinds of 150,000, 30,000, and 4,000 were mixed were measured separately.

<Synthesis example>

(Synthesis Example 1)

1.88 g (7.70 mmol) of DA-1 and 1.17 g (2.11 mmol) of DA-3, and 1.67 g (4.20 mmol) of DA-2 were taken in a 50 ml four-neck flask equipped with a stirring device and a nitrogen inlet tube, 40.00 g of NMP was added, and it stirred, sending nitrogen, and made it melt|dissolve. While stirring this diamine solution, 2.04 g (9.10 mmol) of 1,3DMCBDA was added, followed by further stirring, when the viscosity was stable, 0.62 g (3.16 mmol) of CBDA was added, and NMP was further added so that the solid content concentration was 15% by mass. It added and stirred at room temperature for 24 hours, and obtained the solution of polyamic acid (PAA-1). The viscosity in 25 degreeC of this polyamic-acid solution was 212 mPa*S.

(Synthesis Example 2)

30 g of PAA-1 obtained in Synthesis Example 1 was weighed into a 100 ml four-necked flask provided with a stirring device and a nitrogen introduction tube, and NMP was added and diluted so that solid content concentration might be 8 mass %.

Next, 2.61 g (25.5 mmol) of acetic anhydride and 0.67 g (8.47 mmol) of pyridine were added and dissolved. Next, this solution was heated to 55 degreeC while stirring, and it was made to react for 3 hours. The obtained polyamic acid-soluble polyimide acid solution was poured into methanol in an amount equivalent to 3.5 times the total solution while stirring, and reprecipitated. The powder after reprecipitation is filtered by natural filtration or suction filtration, and thereafter, 0.188 L (5.86 mmol) of methanol is divided into two portions, respectively, washed, and dried to obtain a white polyamic acid-soluble polyimide. A resin powder (PWD-1) was obtained. The molecular weight of this resin powder was Mn=13,493, and Mw=27,207.

PWD-1 obtained above was melt|dissolved in NMP, and the polyamic-acid-soluble polyimide resin powder solution (SPI-1) of 12 mass % of solid content concentration was obtained.

(Example 1)

In a 20 ml sample tube in which a stirrer was placed, 6.75 g of the polyamic acid solution (PAA-1) obtained in Synthesis Example 1 was weighed, and 0.81 g of 3-glycidoxypropylmethyldiethoxysilane solution diluted to 1.0 mass% with NMP. , 6.84 g of NMP was added. Then, 3.60g of DAA was added, it stirred for 30 minutes with a magnetic stirrer, and the liquid crystal aligning agent (A-1) was obtained. When liquid crystal aligning agent A-1 was stored at -20 degreeC for 1 week, precipitation of a solid was not observed but it was a uniform solution.

(Examples 2 to 5, Comparative Examples 1 to 6)

The same operation as in Example 1 was followed except that a polyamic acid-soluble polyimide resin powder solution (SPI-1) was used instead of the polyamic acid (PAA-1), or a solvent in the table below was used instead of DAA as the solvent. It implemented and obtained liquid crystal aligning agent (A-2) - (A-5), (B-1) - (B-6), respectively. When all the liquid crystal aligning agents obtained by the above were stored at -20 degreeC for 1 week, precipitation of a solid was not observed but it was a uniform solution. Each result is shown in Table 1 below.

In order to evaluate the electrical properties of the liquid crystal cell, first, a substrate on which electrodes were formed was prepared. The substrate is a glass substrate having a size of 30 mm x 40 mm and a thickness of 1.1 mm. An ITO electrode having a film thickness of 35 nm is formed on the substrate, and the electrode is a stripe pattern having a length of 40 mm and a width of 10 mm.

Next, after filtering a liquid crystal aligning agent with a 1.0-micrometer filter, it apply|coated to the board|substrate with the prepared said electrode by spin coat application|coating. After drying for 5 minutes on a 50 degreeC hotplate, 230 degreeC IR type oven performed baking for 20 minutes, the coating film with a film thickness of 100 nm was formed, and the board|substrate with a liquid crystal aligning film was obtained. After rubbing this liquid crystal aligning film with rayon cloth (roller diameter: 120 mm, number of roller rotations: 1000 rpm, moving speed: 20 mm/sec, indentation length: 0.4 mm), ultrasonic irradiation for 1 minute in pure water to wash After removing a water droplet by , air blow, it dried at 80 degreeC for 15 minute(s), and obtained the board|substrate with a liquid crystal aligning film. After preparing two board|substrates with this liquid crystal aligning film and disperse|distributing a 4 micrometers spacer on the liquid crystal aligning film surface of 1 sheet, a sealing compound is printed from the top, and a rubbing direction is a reverse direction for another board|substrate, and a film surface After affixing this facing and pasting, the sealing compound was hardened and the empty cell was manufactured. Liquid crystal ML-7026-100 (made by Merck Japan) was inject|poured into this empty cell by the reduced pressure injection method, the injection port was sealed, and the liquid crystal cell was obtained. Then, when the obtained liquid crystal cell was heated at 120 degreeC for 60 minute(s), and it cooled to room temperature after that and observed a cell, the orientation was favorable.

<Measurement of voltage retention>

(Example 6)

A voltage of 1V was applied to the liquid crystal cell at a temperature of 60°C for 60 µs, the voltage after 50 ms was measured, and how much the voltage was maintained was calculated as a voltage retention rate.

As a result, the voltage retention in 60 degreeC of the orientation film which consists of orientation agent A-1 was 96.7 %.

(Example 7 - Example 10, Comparative Example 7 - Comparative Example 12)

About the aligning agent (A-2) - the aligning agent (A-5) and the aligning agent (B-1) - the aligning agent (B-6) obtained in Examples 2 - 5 and Comparative Examples 1 - 6 The liquid crystal cell was manufactured by the same method, and the voltage retention was measured with the measuring method as described in Example 6. Each result is shown in Table 2 below.

It is widely useful for a TN element, an STN element, a TFT liquid crystal element, and also the liquid crystal display element of a vertically-aligned type, etc.

Claims (8)

The organic solvent containing the at least 1 sort(s) of polymer chosen from the group which consists of a polyimide and a polyimide precursor, and the solvent of following (A) group and (B) group, The liquid crystal aligning agent characterized by the above-mentioned.
(A) group: at least one solvent selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and γ-butyrolactone
(B) group: at least one solvent selected from 4-methoxy-4-methyl-2-pentanone, 4-hydroxy-2-butanone and 2-methyl-2-hexanol The method of claim 1,
The solvent of the said (A) group contains at least 1 sort(s) chosen from the group which consists of N-methyl- 2-pyrrolidone and (gamma)-butyrolactone, The liquid crystal aligning agent characterized by the above-mentioned. The method of claim 1,
The solvent of the said (A) group is 50 weight% - 95 weight% with respect to total solvent amount, The liquid crystal aligning agent characterized by the above-mentioned. The method of claim 1,
The solvent of the said (B) group is 5 weight% - 50 weight% with respect to total solvent amount, The liquid crystal aligning agent characterized by the above-mentioned. The method of claim 1,
1 mass % - 5 mass % of said polymer are contained, The liquid crystal aligning agent characterized by the above-mentioned. The method of claim 1,
95 mass % - 99 mass % of said organic solvent are contained, The liquid crystal aligning agent characterized by the above-mentioned. It is obtained from the liquid crystal aligning agent in any one of Claims 1-6, The liquid crystal aligning film characterized by the above-mentioned. The liquid crystal aligning film of Claim 7 is provided, The liquid crystal display element characterized by the above-mentioned.