KR20200066656A - Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display element - Google Patents

Abstract

식 중 P₁, P₂ 는 페닐 또는 비페닐기이고 방향 고리 상의 수소는 메틸기 또는 불소기로 치환되어 있어도 된다. 또 Q 는 2 가의 유기기이고, n1, n2 는 0 내지 5 의 정수이다. 단, n1, n2 중 적어도 하나가 0 인 경우 Q 는 산소 원자이다.It is a liquid crystal aligning agent containing the polyimide which is the reactant of the tetracarboxylic dianhydride derivative component and diamine component which consists of at least 1 sort(s) selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and diamine component The liquid crystal aligning agent which contains at least 1 sort(s) chosen from the diamine of following formula [A], and has an imidation ratio of polyimide of 70% or more.

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Further, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.

Description

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

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

The liquid crystal display element is configured by sandwiching a liquid crystal layer by a pair of transparent substrates provided with electrodes. In addition, in the liquid crystal display element, an organic film made of an organic material is used as the liquid crystal alignment film so that the liquid crystal is in a desired alignment state between the substrates. That is, the liquid crystal aligning film is a constituent member of the liquid crystal display element, and is formed on a surface in contact with the liquid crystal of the substrate holding the liquid crystal, and plays a role of aligning the liquid crystal in a constant direction between the substrates. Furthermore, the pretilt angle of the liquid crystal can be controlled by the liquid crystal alignment film. A method of reducing the pretilt angle by mainly selecting the structure of the polyimide (see Patent Documents 1 and 2) is known.

Japanese Patent Application Publication No. Hei 9-188761 Japanese Patent Application Publication No. Hei 10-123532

On the other hand, with the recent high performance of liquid crystal display elements, in addition to applications such as large-screen and high-definition liquid crystal televisions, liquid crystal displays are used for vehicle installations, for example, in car navigation systems, meter panels, surveillance cameras, and medical camera monitors. The device is used, and a lower pretilt angle is required in the rubbing alignment film as well as in the demand for viewing angle characteristics.

Further, the viewing angle dependence of color taste derived from the pretilt angle and so-called color shift are pointed out as problems, and an alignment film having a pretilt angle of 1 degree or less is specifically required to solve this problem.

The inventors repeatedly conducted various studies to achieve the above object, and found that the liquid crystal aligning agent according to the following configuration is optimal for achieving the above object, thereby completing the present invention.

In this way, this invention is based on the said knowledge, and has the following summary.

1.It is a liquid crystal aligning agent containing polyimide which is a reactant of a diamine component and a carboxylic acid dihydride derivative composed of at least one selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and diamine The liquid crystal aligning agent whose component contains at least 1 sort(s) selected from the diamine of the following formula [A] (hereinafter also referred to as a specific diamine), and the imidation ratio of polyimide is 70% or more.

[Formula 1]

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. In addition, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.

As a preferable specific example of [A], diamines of following formula [A-1]-[A-6] are mentioned.

[Formula 2]

By using the liquid crystal aligning agent of this invention, the liquid crystal aligning film which satisfies various characteristics required for a liquid crystal aligning film and gives a low pretilt angle of 1 degree or less can be obtained.

<aliphatic and alicyclic tetracarboxylic acid derivatives>

The polyimide contained in the liquid crystal aligning agent of the present invention contains a tetracarboxylic dianhydride derivative component and a specific diamine composed of at least one selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride It is obtained by imidizing the polyimide precursor obtained from the said diamine component (it is also called a specific polymer below). Below, the specific example and manufacturing method of the material used are explained in full detail.

Tetracarboxylic acid derivatives used in the production of polyimide precursors include not only tetracarboxylic dianhydride, but also derivatives thereof, tetracarboxylic acid, tetracarboxylic acid dihalide compound, tetracarboxylic acid dialkyl ester, and tetracar And carboxylic acid dialkyl ester dihalides.

As an aliphatic, alicyclic tetracarboxylic dianhydride, or its derivative, among these, it is preferable to be represented by following formula (4).

[Formula 3]

In Formula (4), preferable structures of X ₁ include the following formulas (X1-1) to (X1-24).

[Formula 4]

[Formula 5]

[Formula 6]

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

The following formula (X1-1-1)-(X1-1-6) is mentioned as a specific example of Formula (X1-1). (X1-1-1) is particularly preferable from the viewpoint of liquid crystal alignment and sensitivity of the photoreaction.

[Formula 7]

<specific diamine>

The diamine component used in the production of the polyimide contained in the liquid crystal aligning agent of the present invention contains at least one selected from diamines represented by the following formula [A].

[Formula 8]

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Further, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.

Here, when (n1 + n2) ≥ 1, and one of n1 and n2 is 0, Q is preferably an oxygen atom, and the formula [A] in this case is represented by the following [A'].

[Formula 9]

In the formula, X is a divalent organic group selected from the following structures.

[Formula 10]

* Represents a bond with an oxygen atom, respectively.

As a preferable specific example of [A], diamines of following formula [A-1]-[A-6] are mentioned. These may be individual or may be a combination of multiple.

[Formula 11]

The preferable content of the diamine of the formula [A] is preferably 40% to 80% of the total diamine component, more preferably 40% to 70%, and even more preferably 40% to 60%.

<Other diamines>

As the diamine component used in the production of the polyimide contained in the liquid crystal aligning agent of the present invention, in addition to the diamine of the formula [A], various diamines can be used depending on the properties of the liquid crystal aligning agent required.

Other diamines are represented by the following formula (5).

[Formula 12]

In the formula (5), 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.

The structure of Y ₁ is not particularly limited. Preferred structures include the following (Y-1) to (Y-177).

[Formula 13]

[Formula 14]

[Formula 15]

[Formula 16]

[Formula 17]

[Formula 18]

[Formula 19]

[Formula 20]

[Formula 21]

[Formula 22]

[Formula 23]

[Formula 24]

[Formula 25]

[Formula 26]

[Formula 27]

[Formula 28]

[Formula 29]

[Formula 30]

[Formula 31]

In the formula, Me represents a methyl group, and R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[Formula 32]

From the viewpoint of improving the solubility of the polymer, it is preferable to include a structure represented by the following formula (6) in the structure of any Y ₁ .

[Formula 33]

In the formula (6), D is preferably a heat-desorbing group that is desorbed at 150 to 230°C, more preferably at 180 to 230°C, and is replaced with a hydrogen atom. (Y-124), (Y-158)-(Y-163) are mentioned as a specific example of Y containing the structure represented by said formula (6).

<polyamic acid>

The polyamic acid which is a polyimide precursor used in the present invention contains a tetracarboxylic dianhydride derivative component and a specific diamine composed of at least one selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride. It is a polyimide precursor obtained from the said diamine component, and can be manufactured by the method shown below.

Specifically, the tetracarboxylic dianhydride derivative component consisting of at least one selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride and a diamine component containing a specific diamine in the presence of an organic solvent. It can be synthesized by reacting at -20°C to 150°C, preferably 0°C to 50°C for 30 minutes to 24 hours, preferably 1 to 12 hours.

The organic solvent used for the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of monomers and polymers. You may mix and use the above. The concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that the precipitation of the polymer does not occur easily and a high molecular weight body is easily obtained.

The polyamic acid obtained as described above can be recovered by depositing a polymer by injecting the reaction solution into an empty solvent while stirring well. Moreover, the powder of the purified polyamic acid can be obtained by carrying out precipitation several times, washing with a poor solvent, and drying at room temperature or by heating. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Polyamic acid ester>

The polyamic acid ester which is one of the polyimide precursors used in the present invention can be produced by the methods (I), (II) or (III) shown below.

(I) When manufacturing with polyamic acid

The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine. Specifically, the polyamic acid and the esterifying agent are synthesized by reacting at -20°C to 150°C, preferably 0°C to 50°C in the presence of an organic solvent for 30 minutes to 24 hours, preferably 1 to 4 hours. Can be.

As an esterifying agent, it is preferable that it can be easily removed by purification, N,N-dimethylformamide dimethylacetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamidedineopentylbutylacetal, N,N-dimethylformamidedi-t-butylacetal, 1-methyl-3-p-tolyltriagene, 1-ethyl-3-p-tolyltriagene , 1-propyl-3-p-tolyltrigen, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, and the like. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents per 1 mole of the repeating unit of the polyamic acid.

The solvent used for the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the solubility of the polymer. You may use it. The concentration of the polymer in the reaction solution is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass, from the viewpoint that precipitation of the polymer does not occur easily and a high molecular weight body is easily obtained.

(II) When prepared by reaction of tetracarboxylic acid diester dichloride and diamine

The polyamic acid ester can be produced from tetracarboxylic acid diester dichloride and diamine. Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to It can be synthesized by reacting for 4 hours.

Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, but pyridine is preferred for the reaction to proceed gently. The amount of the base used is 2 to 4 times the molar with respect to the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and easy to obtain a high molecular weight body.

The solvent used for the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone from the solubility of monomers and polymers, and these may be used alone or in combination of two or more. The polymer concentration in the reaction solution is preferably from 1 to 30% by mass, more preferably from 5 to 20% by mass, from the viewpoint that the precipitation of the polymer does not occur easily and a high molecular weight body is easily obtained. Moreover, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is desirably dehydrated as much as possible, and it is preferable to prevent the incorporation of outside air in a nitrogen atmosphere. .

(III) When prepared by reaction of tetracarboxylic acid diester and diamine

The polyamic acid ester can be produced by polycondensing a tetracarboxylic acid diester and diamine. Specifically, tetracarboxylic acid diester and diamine are present in a condensing agent, a base, and an organic solvent at 0°C to 150°C, preferably 0°C to 100°C, for 30 minutes to 24 hours, preferably 3 It can be produced by reacting for 15 hours.

Examples of the condensing agent include triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, and dimethoxy-1 ,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazole- 1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphite, diphenyl (2,3-dihydro-2-thioxo-3-benzooxazolyl)phosphonate, etc. Can be used. The amount of the condensing agent added is preferably 2 to 3 times the mole relative to the tetracarboxylic acid diester.

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

Moreover, in the said reaction, reaction advances efficiently by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferred. The amount of Lewis acid added is preferably 0 to 1.0 times the mole relative to the diamine component.

Among the above three polyamic acid ester production methods, the production method of the above (I) or (II) is particularly preferred because a high molecular weight polyamic acid ester is obtained.

The solution of the polyamic acid ester obtained as described above can be precipitated by injecting it into a poor solvent while stirring well. Precipitation is carried out several times, and after washing with a poor solvent, it is dried at room temperature or by heating to obtain a powder of the purified polyamic acid ester. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Polyimide>

The polyimide used in the present invention can be produced by imidizing the polyamic acid or polyamic acid ester. The imidation ratio of the polyimide used in the present invention is preferably 70 to 99% from the viewpoint of electrical properties. When preparing a polyimide with a polyamic acid ester, chemical imidization is simple by adding a basic catalyst to a polyamic acid solution obtained by dissolving the polyamic acid ester solution or a polyamic acid ester resin powder in an organic solvent. Chemical imidation is preferable because the imidation reaction proceeds at a relatively low temperature and the molecular weight of the polymer does not easily decrease in the course of imidization.

Chemical imidation can be performed by stirring the polyamic acid or polyamic acid ester 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 polymerization reaction described above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has basicity suitable for advancing the reaction. Further, examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among these, acetic anhydride is preferred because purification after completion of the reaction becomes easy.

The temperature during the imidization reaction is, for example, -20°C to 120°C, preferably 0°C to 100°C, and the reaction time can be carried out for 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mole times of the amic acid group, preferably 2 to 20 mole times, and the amount of the acid anhydride is 1 to 50 mole times of the amic acid group, preferably 3 to 30 mole times. The imidation rate of the obtained polymer can be controlled by adjusting the catalyst amount, temperature, and reaction time.

Since the added catalyst or the like remains in the solution after the imidation reaction of the polyamic acid ester or the polyamic acid, the imidized polymer obtained is recovered by the means described below, re-dissolved in an organic solvent, and the liquid crystal of the present invention It is preferable to use it as an alignment agent.

The solution of the polyimide obtained as described above can be precipitated by injecting it into a poor solvent while stirring well. Precipitation is carried out several times, and after washing with a poor solvent, it is dried at room temperature or by heating to obtain a powder of the purified polyamic acid ester.

The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

<Liquid crystal aligning agent>

The liquid crystal aligning agent of the present invention has a form in which a polymer containing a specific polymer is dissolved in an organic solvent. The molecular weight of the polyimide precursor and polyimide described in the present invention is preferably 2,000 to 500,000 as a weight average molecular weight, more preferably 5,000 to 300,000, and even more preferably 10,000 to 100,000. Moreover, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.

As for content of the specific polymer in the liquid crystal aligning agent of this invention, 2-10 mass% is preferable in a liquid crystal aligning agent, and 3-8 mass% is more preferable.

The liquid crystal aligning agent of this invention may contain the polyamic acid which is a reaction material of arbitrary tetracarboxylic-acid derivative component and arbitrary diamine component other than a specific polymer.

Moreover, when a liquid crystal aligning agent contains the said polyamic acid, 10-900 mass parts is preferable with respect to 100 mass parts of polyimides, and 25-700 mass parts is more preferable.

Other polymers may be mixed in all the polymer components in the liquid crystal aligning agent of the present invention. Examples of the other polymers include cellulose-based polymers, acrylic polymers, methacryl polymers, polystyrenes, polyamides, and polysiloxanes. The content of the other polymers is preferably 0.5 to 15 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the polyimide or polyamic acid in total.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed depending on the setting of the thickness of the coating film to be formed, but is preferably 1% by weight or more from the viewpoint of forming a uniform and defect-free coating film. From the viewpoint of storage stability, 10 wt% or less is preferable.

The solvent in the liquid crystal aligning agent of the present invention is a solvent for dissolving a polyimide precursor and a polyimide (also referred to as a positive solvent) or a coating property or surface smoothness of a liquid crystal aligning film when a liquid crystal aligning agent is applied. A solvent to improve (also called poor solvent) is preferably used. Below, although the specific example of another solvent is given, it is not limited to these examples.

Specific examples of the good solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, 1,3-dimethylimidazolidinone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N -Dimethylpropanamide or 4-hydroxy-4-methyl-2-pentanone.

As a specific example of a poor solvent, 1-butoxy-2-propanol, 2-butoxy-1-propanol, 2-propoxyethanol, 2-(2-propoxyethoxy)ethanol, 1-propoxy-2 -Propanolethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl Alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexane All, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2, 3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol Dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3- Pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol Diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, butyl cellosolve, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, Diethylene glycol, propylene glycol, 1-(butoxyethoxy)propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene Glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate Diethylene glycol monoethyl ether acetate, propylene glycol diacetate, diisopentyl ether, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, triethylene glycol, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate , 3-ethyl ethoxypropionate, 3-methoxypropionate ethyl, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionic acid butyl, lactic acid methyl ester, lactic acid ethyl ester, And lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, diisobutyl ketone, ethyl carbitol, and the like.

Moreover, the solvent represented by the following formula is also preferably used as a poor solvent.

[Formula 34]

R ₂₄ and R ₂₅ are each a linear or branched alkyl group having 1 to 8 carbon atoms. However, R ₂₄ + R ₂₅ is an integer greater than 3.

Moreover, as a poor solvent, when the solubility of the polyimide precursor and polyimide contained in a liquid crystal aligning agent is high in the solvent, the solvent represented by the following [D-1]-Formula [D-3] is preferable.

[Formula 35]

In formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, in formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-3], D ³ Represents a C1-C4 alkyl group.

Moreover, the liquid crystal aligning agent of this invention is at least 1 sort(s) of substituent chosen from the group which consists of a crosslinkable compound which has an epoxy group, an isocyanate group, an oxetane group, or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group, and a lower alkoxyalkyl group. It may contain the crosslinkable compound which has, or the crosslinkable compound which has a polymerizable unsaturated bond.

As the crosslinkable compound, various known compounds can be used depending on the purpose. The following compounds are preferably used.

[Formula 36]

The content of the crosslinkable compound is preferably 0.1 to 150 parts by mass based on 100 parts by mass of all polymer components. Especially, 0.1-100 mass parts is preferable and 1-50 mass parts is more preferable in order for crosslinking reaction to advance and to express the desired effect.

The liquid crystal aligning agent of this invention can contain the compound which improves the uniformity and surface smoothness of the film thickness of a liquid crystal aligning film when apply|coating a liquid crystal aligning agent.

Fluorine-based surfactants, silicone-based surfactants, and non-ionic surfactants are examples of the compounds that improve the uniformity and surface smoothness of the film thickness of the liquid crystal alignment film.

The surfactant is used in an amount of preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

Moreover, you may contain the silane coupling agent for the purpose of improving the adhesiveness of a liquid crystal aligning film and a board|substrate, or an imidation accelerator for the purpose of efficiently carrying out the imidation by heating a polyimide precursor when baking a coating film.

<Liquid crystal alignment film, liquid crystal display element>

The liquid crystal aligning film of this invention is a film obtained by apply|coating said liquid crystal aligning agent to a board|substrate, and drying and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate, or a polycarbonate substrate can also be used. At that time, using a substrate on which an ITO electrode or the like for driving a liquid crystal is formed is preferable from the viewpoint of simplifying the process. Moreover, in the reflective liquid crystal display element, an opaque material such as a silicon wafer can be used as long as it is a substrate on one side, and a material that reflects light such as aluminum can also be used for the electrode in this case.

The coating method of the liquid crystal aligning agent is generally industrially performed by screen printing, offset printing, flexo printing, inkjet method or the like, and other coating methods include dip method, roll coater method, and slit coater method. , Spinner method or spray method is known.

After the liquid crystal aligning agent is applied onto the substrate, the solvent can be evaporated to form a liquid crystal alignment film by heating means such as a hot plate, a heat cycle oven, or an IR (infrared) type oven. Any temperature and time can be selected for the drying and firing steps after applying the liquid crystal aligning agent. Normally, conditions for firing at 50 to 120°C for 1 to 10 minutes and then firing at 150 to 300°C for 5 to 120 minutes are mentioned in order to sufficiently remove the contained solvent. When the thickness of the liquid crystal alignment film after firing is too thin, reliability of the liquid crystal display element may be lowered, so 5 to 300 nm is preferable, and 10 to 200 nm is more preferable.

The liquid crystal aligning agent of this invention can be used as a liquid crystal aligning film, after apply|coating and baking on a board|substrate, and performing an alignment process by rubbing process, photo-alignment process, etc., and without an alignment process in vertical alignment use etc. In an orientation treatment such as rubbing treatment or photo-alignment treatment, a known method or apparatus can be used.

As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. Further, a liquid crystal display element having an active matrix structure may be formed in which a switching element such as a TFT (Thin Film Transistor) is formed in each pixel portion constituting the image display.

Specifically, a transparent glass substrate is prepared, a common electrode is formed on one substrate, and a segment electrode is formed on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned to display desired images. Next, an insulating film is formed on each substrate by covering the common electrode and the segment electrode. The insulating film can be, for example, a SiO ₂ -TiO ₂ film formed by a sol-gel method.

Next, a liquid crystal alignment film is formed on each of the substrates, and the other substrates are overlapped with one another so that the surfaces of the liquid crystal alignment films face each other, and the periphery is adhered with a sealing agent. In order to control the substrate gap in the sealing agent, it is usually preferable to mix a spacer, and to spread the spacer for controlling the substrate gap in the in-plane portion where the sealing agent is not formed. An opening capable of filling the liquid crystal from the outside is formed in a part of the sealing agent. Subsequently, the liquid crystal material is injected into the space surrounded by the two substrates and the sealing agent through the opening formed in the sealing agent, and then the opening is sealed with an adhesive. For injection, a vacuum injection method may be used, or a method using a capillary phenomenon in the atmosphere may be used. The liquid crystal material may be either a positive type liquid crystal material or a negative type liquid crystal material, but a preferred type is a negative type liquid crystal material. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates are affixed to the surface opposite to the liquid crystal layer of the two substrates.

Example

Hereinafter, the present invention will be specifically described with reference to examples and the like, but the present invention is not limited to these examples. In addition, the symbol of a compound and a solvent is as follows.

NMP: N-methyl-2-pyrrolidone

GBL: γ-butyrolactone

BCS: Butyl Cellosolve

DA-1 to DA-12, CA-1 to CA-6: Compounds represented by the following structural formula.

AD-1: 3-glycidoxypropyltriethoxysilane

AD-2: A compound represented by the following structural formula.

[Formula 37]

[Formula 38]

<viscosity>

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

<Measurement of imidation rate of polyimide>

The imidation ratio of the polyimide in the synthesis example was measured as follows. 30 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Science)), and mixed with deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane)) Product) (0.53 mL) was added, and ultrasonic waves were added to completely dissolve. This solution was measured for a 500 MHz proton NMR by an NMR meter (JNW-ECA500) (manufactured by Nippon Electronics Datum Co., Ltd.). The imidation rate is determined by setting a proton derived from a structure that does not change before and after imidization as a reference proton, and a peak integrated value of this proton and a proton peak derived from the NH group of amic acid appearing at around 9.5 ppm to 10.0 ppm. It calculated|required by the following formula using the integrated value.

Imidation rate (%) = (1-αx/y) × 100

In the above formula, x is a proton peak integrated value derived from NH group of amic acid, y is a peak integrated value of reference proton, α is NH of amic acid in the case of polyamic acid (imidation rate is 0%) This is the ratio of the number of reference protons to one proton.

(Synthesis Example 1)

To a 7 liter separable flask with a stirring device and nitrogen introduction tube, DA-1 was 225 g (3770 mmol), DA-2 was 167 g (419 mmol), and DA-3 was 117 g (210 m) Mol) Weighed and taken, 3130 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 204 g (910 mmol) of CA-1 was added, 616 g of NMP was further added, and the mixture was stirred at 40° C. under nitrogen atmosphere for 6 hours. Further, 79.0 g (402 mmol) of CA-2 was added, 709 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 270 mPa·s) PAA-B1 Got

To a 2 L Erlenmeyer flask containing a stirrer, 400 g of a solution of this polyamic acid was added, 350 g of NMP, 32.4 g of acetic anhydride, 8.39 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then at 55°C. The reaction was carried out for 4 hours. This reaction solution was poured into 2770 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 87%).

Furthermore, 40.0 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 293 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A1.

(Synthesis Example 2)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.24 m) of DA-3 Mol) Weighed and taken, 54.3 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, 15.5 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.26 g (11.5 mmol) of CA-2 was added, 6.80 g of NMP was further added, and stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1300 mPa·s).

To a 100 ml Erlenmeyer flask containing a stirrer, 27.0 g of this polyamic acid solution was aliquoted, 18.0 g of NMP, 2.96 g of acetic anhydride, 0.766 g of pyridine were added, stirred at room temperature for 30 minutes, and then stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 86%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 4.00 g of this polyimide powder was aliquoted, 29.3 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A2.

(Synthesis Example 3)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.24 m) of DA-3 Mol) Weighed and taken, 50.9 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, 18.0 g of NMP was further added, and the mixture was stirred at 50°C under nitrogen atmosphere for 1 hour. Further, 2.63 g (11.7 mmol) of CA-1 was added, 9.70 g of NMP was further added, and stirred at 40°C for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1180 mPa·s).

To a 100 ml Erlenmeyer flask containing a stirrer, 25.0 g of this polyamic acid solution was aliquoted, 8.33 g of NMP, 2.96 g of acetic anhydride, 0.766 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes, and then at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 86%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 4.00 g of powder of this polyimide was aliquoted, 29.3 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain SPI-A3 solution of polyimide.

(Synthesis Example 4)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 4.82 g (16.4 mmol) of DA-1, 3.58 g (8.98 mmol) of DA-2, and 2.50 g (4.49 m) of DA-3. Mol) Weighed and taken, 53.3 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 4.96 g (22.1 mmol) of CA-1 was added, 19.3 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 1.50 g (5.99 mmol) of CA-4 was added, 6.35 g of NMP was further added, and the mixture was stirred at 40°C for 15 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 427 mPa·s).

To a 100 ml Erlenmeyer flask containing a stirrer, 30.0 g of a solution of this polyamic acid is aliquoted, 15.0 g of NMP, 2.85 g of acetic anhydride, 0.737 g of pyridine are added, stirred at room temperature for 30 minutes, and then at 55°C. It was reacted for 3 hours. This reaction solution was poured into 170 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 84%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 4.00 g of this polyimide powder was aliquoted, 29.3 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A4.

(Synthesis Example 5)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 2.89 g (9.88 mmol) of DA-1, 3.94 g (9.89 mmol) of DA-2, and 2.75 g (4.94 m) of DA-3 Mol) and 2.0-4 g (8.22 mmol) of DA-4 were weighed, 49.5 g of NMP was added, and the mixture was dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 4.25 g (21.4 mmol) of CA-3 was added, 14.7 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.04 g (10.4 mmol) of CA-2 was added, 6.96 g of NMP was further added, and stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1170 mPa·s).

To a 100 ml Erlenmeyer flask containing a stirrer, 25.0 g of a solution of this polyamic acid is aliquoted, 16.6 g of NMP, 2.81 g of acetic anhydride, 0.728 g of pyridine are added, stirred at room temperature for 30 minutes, and stirred at 55°C. It was reacted for 3 hours. This reaction solution was poured into 160 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a powder of polyimide (imidation ratio: 82%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 4.00 g of this polyimide powder was aliquoted, 29.3 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A5.

(Synthesis Example 6)

In a 300 ml eggplant flask with a stirring device and nitrogen introduction tube, 6.33 g (15.8 mmol) of DA-2, 4.42 g (7.94 mmol) of DA-3, 8.52 g (29.1 m) of DA-8 Mol) Weighed and taken, 150 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 7.72 g (34.4 mmol) of CA-1 was added, 10.0 g of NMP was further added, and the mixture was stirred at 40°C under nitrogen atmosphere for 6 hours. Further, 3.38 g (17.2 mmol) of CA-2 was added, 10.0 g of NMP was further added, and the mixture was stirred for 2 hours at 23° C. under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 190 mPa·s).

To a 500 ml Erlenmeyer flask containing a stirrer, 150 g of this polyamic acid solution is aliquoted, 130 g of NMP, 12.1 g of acetic anhydride, 3.13 g of pyridine are added, stirred at room temperature for 30 minutes, and then at 55°C. The reaction was carried out for 4 hours. This reaction solution was poured into 1040 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 81%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 4.00 g of this polyimide powder was aliquoted, 29.3 g of NMP was added and dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A6.

(Synthesis Example 7)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, DA-5 was 1.12 g (4.49 mmol), DA-6 was 1.49 g (7.47 mmol), and DA-7 was 0.590 g (2.97 m) Mol) Weighed and taken, 15.5 g of NMP and 15.5 g of GBL were added and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 1.15 g (5.86 mmol) of CA-2 was added, 5.00 g of NMP and 5.00 g of GBL were further added, and the mixture was stirred at 25°C under nitrogen atmosphere for 1 hour. Further, 2.60 g (8.83 mmol) of CA-5 was added, 5.00 g of NMP and 5.00 g of GBL were further added, and the mixture was stirred at 50°C for 12 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 200 mPa). S) PAA-A1 was obtained.

(Synthesis Example 8)

30.0 g of a solution PAA-B1 of the polyamic acid obtained in Synthesis Example 1 is aliquoted, 26.2 g of NMP, 2.44 g of acetic anhydride, 0.630 g of pyridine are added, stirred at room temperature for 30 minutes, and then reacted at 40°C for 30 minutes. Ordered. This reaction solution was poured into 150 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 40%).

Furthermore, 2.00 g of this polyimide powder was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 14.6 g of NMP was added and dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-B1.

(Synthesis Example 9)

In a 200 ml eggplant flask with a stirring device and nitrogen introduction tube, 8.0-1 g (27.5 mmol) of DA-1, 5.98 g (15.0 mmol) of DA-2, and 4.17 g (7.50 m) of DA-3. Mol) Weighed and taken, 111 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 7.29 g (32.5 mmol) of CA-1 was added, 22.0 g of NMP was further added, and the mixture was stirred at 40° C. under nitrogen atmosphere for 6 hours. Further, 3.16 g (14.5 mmol) of CA-6 was added, 28.5 g of NMP was further added, and the mixture was stirred at 50°C for 12 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 280 mPa·s).

To a 300 ml Erlenmeyer flask containing a stirrer, 100 g of the solution of this polyamic acid is aliquoted, 87.5 g of NMP, 8.02 g of acetic anhydride, 2.07 g of pyridine are added, stirred at room temperature for 30 minutes, and then at 55°C. The reaction was carried out for 4 hours. This reaction solution was poured into 700 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a powder of polyimide (imidation ratio: 82%).

Furthermore, 10.0 g of powder of this polyimide was aliquoted into a 500 ml Erlenmeyer flask containing a stirrer, 73.3 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-B2.

(Synthesis Example 10)

To a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 5.62 g (19.3 mmol) of DA-8, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 m) of DA-3. Mol) Weighed and taken, 54.3 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 4.5-3 g (22.8 mmol) of CA-3 was added, 15.5 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.29 g (11.7 mmol) of CA-2 was added, 8.30 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1210 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was carried out using the obtained polyamic acid to obtain a powder of polyimide (imidation rate: 83%), and further dissolved in NMP to obtain a solution of polyimide SPI-A7. Got.

(Synthesis Example 11)

To a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 5.62 g (19.3 mmol) of DA-9, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 m) of DA-3. Mol) Weighed and taken, 54.3 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 4.5-3 g (22.8 mmol) of CA-3 was added, 15.5 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.33 g (11.9 mmol) of CA-2 was added, 8.50 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 900 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain a powder of polyimide (imidation rate: 80%), and further dissolved in NMP to obtain a solution of polyimide SPI-A8. Got.

(Synthesis Example 12)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, DA-10 was 7.09 g (19.3 mmol), DA-2 was 4.18 g (10.5 mmol), and DA-3 was 2.92 g (5.25 m). Mol) Weighed and taken, 60.5 g of NMP was added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 4.5-3 g (22.8 mmol) of CA-3 was added, 15.2 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.25 g (11.5 mmol) of CA-2 was added, 8.10 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1250 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was performed using the obtained polyamic acid to obtain a polyimide powder (imidation ratio: 75%), and further dissolved in NMP to obtain a solution of polyimide SPI-A9. Got.

(Synthesis Example 13)

To a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, 7.11 g (19.3 mmol) of DA-11, 4.18 g (10.5 mmol) of DA-2, and 2.92 g (5.25 m) of DA-3 Mol) Weighed and taken, 61.8 g of NMP was added, and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 4.5-3 g (22.8 mmol) of CA-3 was added, 15.2 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.30 g (11.7 mmol) of CA-2 was added, 8.20 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 980 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was carried out using the obtained polyamic acid to obtain a powder of polyimide (imidation ratio: 81%), and further dissolved in NMP to obtain a solution of polyimide SPI-A10. Got.

(Synthesis Example 14)

In a 100 ml eggplant flask with a stirring device and nitrogen introduction tube, DA-12 was 9.17 g (19.3 mmol), DA-2 was 4.18 g (10.5 mmol), and DA-3 was 2.92 g (5.25 m). Mol) Weighed and taken, 69.4 g of NMP was added and dissolved by stirring while feeding nitrogen. While stirring the diamine solution under water cooling, 4.5-3 g (22.8 mmol) of CA-3 was added, 14.8 g of NMP was further added, and the mixture was stirred at 50°C for 1 hour under a nitrogen atmosphere. Further, 2.34 g (12.0 mmol) of CA-2 was added, 8.30 g of NMP was further added, and the mixture was stirred at 23° C. for 2 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 1030 mPa·s).

In the same manner as in Synthesis Example 2, chemical imidization was carried out using the obtained polyamic acid to obtain a polyimide powder (imidation ratio: 83%), and further dissolved in NMP to obtain a solution of polyimide SPI-A11. Got.

(Synthesis Example 15)

To a 100 ml Erlenmeyer flask containing a stirrer, 30.0 g of a solution of the polyamic acid obtained in Synthesis Example 2 was aliquoted, and 0.470 g of di-tert-butyl dicarbonate was added, followed by reaction at 40°C for 12 hours. Further, 20.0 g of NMP, 3.85 g of acetic anhydride, and 1.28 g of pyridine were added, stirred at room temperature for 30 minutes, and reacted at 60°C for 4 hours. This reaction solution was poured into 220 g of methanol, and the obtained precipitate was filtered off. After washing this precipitate with methanol, it was dried under reduced pressure at a temperature of 80°C to obtain a polyimide powder (imidation ratio: 90%).

Further, to a 500 ml Erlenmeyer flask containing a stirrer, 3.50 g of this polyimide powder was aliquoted, 25.6 g of NMP was added, and the mixture was dissolved by stirring at 70°C for 24 hours to obtain a solution of polyimide SPI-A12.

(Examples 1 to 15) and (Comparative Examples 1 to 3)

The solutions obtained by mixing the solution of the polyamic acid and the solution of the polyimide obtained in Synthesis Examples 1 to 15 in proportions of the polymers 1 and 2 shown in the following table, NMP, GBL, BCS, AD-1 The NMP solution containing 1% by weight and the NMP solution containing 10% by weight of AD-2 were added with stirring to a composition shown in the table below, and further stirred at room temperature for 2 hours to compare Examples 1 to 15 and The liquid crystal aligning agents of Examples 1-3 were obtained.

Below, the manufacturing method of the liquid crystal cell 1 for evaluating a pretilt angle and voltage retention, and the liquid crystal cell 2 for evaluating liquid crystal alignability are shown.

[Production of Liquid Crystal Cell 1]

At the very beginning, an electrode-attached substrate was prepared. The substrate is a glass substrate having a size of 30 mm × 40 mm and a thickness of 1.1 mm. An ITO electrode with a film thickness of 35 nm is formed on the substrate, and the electrode is a stripe pattern with a length of 40 mm and a width of 10 mm.

Next, the liquid crystal aligning agent was filtered through a filter having a pore diameter of 1.0 µm, and then applied to the prepared substrate with an electrode by spin coating. After drying on a hot plate at 80°C for 2 minutes, baking was performed for 20 minutes in an IR oven at 230°C to form a coating film having a film thickness of 100 nm to obtain a substrate with a liquid crystal alignment film. After rubbing this liquid crystal alignment film with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm/sec, indentation length: 0.4 mm), ultrasonic washing is performed in pure water for 1 minute to wash. Then, the water droplets were removed by air blow, and then dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with this liquid crystal aligning film were prepared, and after dispersing a 4 µm spacer on the one liquid crystal aligning film surface, a sealing agent was printed from above, and the rubbing direction of the other one substrate was reversed, and the film surface was reversed. After adhering to each other, an empty cell was prepared by curing the sealing agent. A liquid crystal MLC-3019 (manufactured by Merck Corporation) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 120°C for 1 hour, and left at 23°C overnight, and then used for each evaluation.

[Production of Liquid Crystal Cell 2]

A glass substrate with an electrode having a size of 30 mm×35 mm and having a thickness of 0.7 mm was prepared. On the substrate, an IZO electrode having a printed pattern that forms a counter electrode as a first layer is formed. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by a CVD method is formed. The thickness of the second layer of the SiN film is 500 nm, and functions as an interlayer insulating film. On the second layer of the SiN film, a comb-shaped pixel electrode formed by patterning the IZO film as the third layer is disposed, and two pixels of the first pixel and the second pixel are formed. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-shaped shape formed by arranging a plurality of “ku-shaped” electrode elements in which the central portion is bent, as shown in FIG. 3 described in JP 2014-77845 A. The width of each electrode element in the short direction is 3 µm, and the spacing between the electrode elements is 6 µm. Since the pixel electrode forming each pixel is constituted by arranging a plurality of “ku-shaped” electrode elements in which the central portion is bent, the shape of each pixel is not rectangular, but is bent in the central portion as in the electrode element. , It has a shape similar to that of the bold "ku". And each pixel is divided|segmented up and down with the central curved part as a boundary, and has a 1st upper region and a 2nd lower region.

When the first area and the second area of each pixel are compared, the direction of formation of the electrode elements of the pixel electrodes constituting them is different. That is, based on the rubbing direction of the liquid crystal alignment layer to be described later, in the first region of the pixel, the electrode element of the pixel electrode is formed to form an angle (clockwise) of +10°, and in the second region of the pixel, the pixel electrode The electrode element is formed to form an angle (clockwise) of -10°. Further, in the first and second regions of each pixel, the directions of rotation operations (inflation/switching) in the substrate surface of the liquid crystal caused by the application of the voltage between the pixel electrode and the counter electrode are reversed to each other. Consists of.

Next, after filtering the liquid crystal aligning agent with a filter having a pore diameter of 1.0 µm, an ITO film was formed on the back surface as the substrate with the electrode and a counter substrate, and a glass substrate having a columnar spacer having a height of 4 µm. Each was spin-coated. Subsequently, after drying for 2 minutes on a hot plate at 80°C, baking was performed at 230°C for 20 minutes to obtain a polyimide film having a thickness of 60 nm on each substrate. After rubbing this liquid crystal alignment film with a rayon cloth (roller diameter: 120 mm, roller rotational speed: 500 rpm, moving speed: 30 mm/sec, indentation length: 0.3 mm), ultrasonic washing is performed in pure water for 1 minute to wash. Then, the water droplets were removed by air blow, and then dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film.

Using two types of substrates to which the liquid crystal alignment film was attached, each rubbing direction was combined so as to be antiparallel, and the liquid crystal injection port was left to seal around, and an empty cell having a cell gap of 3.8 μm was manufactured. After vacuum-injecting liquid crystal MLC-3019 (manufactured by Merck Co., Ltd.) into the empty cell at room temperature, the injection port was sealed to obtain an anti-parallel-oriented liquid crystal cell. The obtained liquid crystal cell constituted the FFS mode liquid crystal display element. Thereafter, the liquid crystal cell was heated at 120°C for 1 hour, and left at 23°C overnight, and then used for each evaluation described below.

<Pretilt angle>

The pretilt angle in the liquid crystal cell 1 was evaluated using the AxoScan Muller matrix polarimeter manufactured by OptoMatrix.

<Voltage retention rate>

The voltage of 1 V was applied to the liquid crystal cell 1 at a temperature of 60° C. for 60 μsec, the voltage after 50 msec was measured, and how much the voltage was maintained was evaluated as a voltage retention rate.

<Evaluation of liquid crystal orientation>

Using the liquid crystal cell 2, an alternating voltage of 9 VPP was applied for 170 hours at a frequency of 30 Hz in a constant temperature environment of 60°C. Thereafter, the liquid crystal cell was short-circuited between the pixel electrode and the counter electrode, and left at room temperature for one day.

After standing at 23° C. overnight, this liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the backlight is turned on in a state where no voltage is applied, and the arrangement angle of the liquid crystal cell is adjusted so that the luminance of transmitted light is the smallest. Adjusted. Then, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel is darkest to the angle at which the first region is darkest is calculated as the angle Δθ1, and the second region is equally identical to the second region. The angle Δθ2 was calculated by comparing the first region. The average value of these Δθ1 and Δθ2 was taken as the angle Δθ of the liquid crystal cell, and the smaller this value was defined and evaluated as having better liquid crystal alignment.

For the liquid crystal display elements using the liquid crystal aligning agents of Examples 1 to 15 and Comparative Examples 1 to 3, the results of the pretilt angle, voltage retention, and angle Δθ of the liquid crystal cell as described above are shown in the following table. .

It can be seen that the liquid crystal display element using the liquid crystal aligning agent of the embodiment of the present invention has a low pretilt angle, a high voltage retention, and good liquid crystal alignment.

Industrial availability

By using the liquid crystal aligning agent of this invention, the liquid crystal aligning film which satisfies various characteristics required for a liquid crystal aligning film and gives a low pretilt angle of 1 degree or less can be obtained.

Claims (9)

It is a liquid crystal aligning agent containing the polyimide which is the reactant of the tetracarboxylic dianhydride derivative component and diamine component which consists of at least 1 sort(s) selected from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride, and diamine component The liquid crystal aligning agent which contains at least 1 sort(s) chosen from the diamine of following formula [A], and has an imidation ratio of polyimide of 70% or more.

In the formula, P ₁ and P ₂ are phenyl or biphenyl groups, and hydrogen on the aromatic ring may be substituted with a methyl group or a fluorine group. Further, Q is a divalent organic group, and n1 and n2 are integers from 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom. According to claim 1,
The liquid crystal aligning agent whose diamine of said formula [A] is at least 1 sort(s) chosen from following formula [A-1]-[A-6].

The method of claim 1 or 2,
The liquid crystal aligning agent whose diamine of said formula [A] is 40%-80% of all diamine components. The method according to any one of claims 1 to 3,
The said diamine component further contains the diamine which has the structure of following formula (6) in the structure, The liquid crystal aligning agent.

In the formula (6), D is a thermally desorbable group that is desorbed at 150 to 230°C and is replaced with a hydrogen atom. The method of claim 4,
The liquid crystal aligning agent whose diamine which has the structure of said formula (6) is at least 1 sort(s) chosen from the following diamine.

In the formula, n is an integer from 1 to 12. The method according to any one of claims 1 to 5,
The liquid crystal aligning agent whose aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride are represented by following formula (4).

In the formula, X ₁ is a structure selected from the following structures.

The method according to any one of claims 1 to 6,
Further, a liquid crystal aligning agent containing a polyamic acid which is a reactant of a tetracarboxylic dianhydride derivative and diamine. The liquid crystal aligning film obtained from the liquid crystal aligning agent of Claims 1-7. The liquid crystal display element provided with the liquid crystal aligning film of Claim 8.