KR20210120012A - Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display element using same - Google Patents

Abstract

식 중 R₁ 은, 트리알킬실릴기를 나타낸다.The liquid crystal aligning agent containing at least 1 sort(s) of the polyamic acid which has a structure of following formula (1), and a polyimide.

In the formula, R ₁ represents a trialkylsilyl group.

Description

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

This invention relates to the liquid crystal display element using the liquid crystal aligning agent used in manufacture of a liquid crystal display element, the liquid crystal aligning film obtained from this liquid crystal aligning agent, and this liquid crystal aligning film.

BACKGROUND ART A liquid crystal display element is known as a light-weight, thin, and low-power display device.

A liquid crystal display element clamps a liquid crystal layer by a pair of transparent board|substrates provided with an electrode, and is comprised. The liquid crystal aligning film for controlling the arrangement|sequence state of a liquid crystal is normally formed in the surface which contact|connects the liquid crystal of a board|substrate. As the liquid crystal aligning film, a polyimide-based liquid crystal aligning film obtained by applying a liquid crystal aligning agent mainly composed of a polyimide precursor such as polyamic acid (also referred to as polyamic acid) or a solution of soluble polyimide to a substrate and baking is used. .

In addition to the liquid crystal aligning film excellent in liquid-crystal orientation and stable pretilt angle expression ability, high voltage retention, alternating current drive from the request|requirements, such as suppression of the contrast fall of a liquid crystal display element, and suggestion of afterimage reduction with high definition of a liquid crystal display element Characteristics such as suppression of the residual image generated by , and less residual charge when a DC voltage is applied are becoming important.

As a polyimide-type liquid crystal aligning film, in order to meet such a request|requirement, the technique which modifies the terminal of a polyamic acid and a polyimide with various structures is beginning to be proposed. For example, in order to achieve improvement in liquid crystal orientation, high pretilt angle, small residual image erasure time, and high reliability, the imidized polymer in which the terminal is modified by reacting with a monoacid anhydride, a monoamine compound, and a monoisocyanate compound has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 2001-296525

However, in recent years, in the high-definition liquid crystal display element for mobile phones and tablet-type terminals which have expanded the share rapidly, the improvement of a further characteristic is calculated|required. In particular, it is required to achieve high reliability at low cost.

In order to acquire high reliability, although it is common to use the liquid crystal aligning agent using a soluble polyimide, manufacture of a soluble polyimide needs to change a polyamic acid in quality, and it needs to be obtained, and compared with manufacture of a polyamic acid, cost becomes high. However, the liquid crystal aligning film using a polyamic acid has a point lacking in the reliability of a film|membrane rather than what used a soluble polyimide.

Even if it uses a polyamic acid, the main objective of this invention is to provide the liquid crystal aligning agent which has reliability equal or more than a soluble polyimide, specifically, high voltage retention characteristic.

MEANS TO SOLVE THE PROBLEM The present inventors came to complete this invention, as a result of earnestly examining in order to solve the said subject. That is, the summary of this invention is as showing below.

1. The liquid crystal aligning agent containing at least 1 sort(s) chosen from the polyamic acid which has a structure of following formula (1), and a polyimide.

[Formula 1]

In the formula, R ₁ represents a trialkylsilyl group.

By using the liquid crystal aligning agent of the present invention, without using a complicated manufacturing process such as polyamic acid ester or soluble polyimide, even if polyamic acid is used, reliability equal to or higher than that of soluble polyimide, specifically, high voltage retention characteristics The liquid crystal aligning agent which has can be obtained. Moreover, even if it applies this invention to a soluble polyimide, the same effect can be acquired.

The liquid crystal aligning agent of this invention contains at least 1 sort(s) of the polyimide which is the polyamic acid which has a structure of following formula (1), and its imidated substance.

[Formula 2]

In the formula, R ₁ represents a trialkylsilyl group. As a specific example, the structure of following formula (1-1) - (1-4) is mentioned. * indicates a bond. More preferably, it is a t-butylsilyl group.

[Formula 3]

In order to introduce such a structure into a polyimide, the method of using a silylating agent is used during and after superposition|polymerization of a polyimide precursor. As the silylating agent used in the present invention, a commercially available silylating agent can be used as long as it can introduce a trialkylsilyl group. Among them, a compound selected from the following formulas (S-1) to (S-5) It is preferable to use More preferably, they are (S-1) and (S-2).

[Formula 4]

<Tetracarboxylic acid derivative>

The polyimide contained in the liquid crystal aligning agent of this invention is obtained by imidating the polyimide precursor obtained from reaction of a tetracarboxylic-acid derivative and diamine. Below, the specific example and manufacturing method of the material used are described in detail.

As a tetracarboxylic acid derivative used for manufacture of a polyimide precursor, not only tetracarboxylic dianhydride, tetracarboxylic acid, the tetracarboxylic-acid dihalide compound which are its derivatives, tetracarboxylic-acid dialkyl ester, tetracarboxylic Acid dialkyl ester dihalide is mentioned.

As tetracarboxylic dianhydride or its derivative(s), especially, what is represented by following formula (3) is preferable.

[Formula 5]

In Formula (3), _{if the structure of X<1>} is a tetravalent organic group, it will not specifically limit. As a preferable specific example, the following formulas (X1-1) - (X1-44) are mentioned. From a viewpoint of liquid-crystal orientation, X<_1> is (X1-1)-(X1-3), (X1-5), (X1-7)-(X1-10), (X1-18), (X1-24) , (X1-27) to (X1-43) are preferable.

[Formula 6]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

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 an alkenyl group having 2 to 6 carbon atoms. It is a 6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, or a phenyl group. In terms of liquid crystal alignment, R ₃ ~ R ₂₃ is a hydrogen atom, a halogen atom, a methyl group, or ethyl group is preferable, and is preferably a hydrogen atom, or a methyl group.

Specific examples of the formula (X1-1) include the following formulas (X1-1-1) to (X1-1-6). From the point of liquid-crystal orientation, (X1-1-1) is especially preferable.

[Formula 12]

<diamine>

The diamine used for manufacture of a polyimide precursor is represented by following formula (2).

[Formula 13]

In said formula (2), A<_1> and A<_2> are each independently a hydrogen atom, or a C1-C5 alkyl group, a C2-C5 alkenyl group, or a C2-C5 alkynyl group.

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

[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]

[Formula 32]

[Formula 33]

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 34]

Especially, _{as a structure of Y<1>} , (Y-7), (Y-8), (Y-16), (Y-17), (Y-18), (Y-20), (Y-21) ), (Y-22), (Y-27), (Y-28), (Y-29), (Y-35), (Y-37), (Y-38), (Y-43), (Y-48), (Y-53) to (Y-56), (Y-61), (Y-64) to (Y-66), (Y-69), (Y-71), (Y -72), (Y-76), (Y-77), (Y-80), (Y-81), (Y-82), (Y-83), (Y-156), (Y-159) ), (Y-160), (Y-161), (Y-162), (Y-168), (Y-169), (Y-170), (Y-171), (Y-173), (Y-175), (Y-178) to (Y-182) are preferable, especially (Y-7), (Y-8), (Y-16), (Y-17), (Y-18) ), (Y-21), (Y-22), (Y-27), (Y-28), (Y-29), (Y-37), (Y-38), (Y-53) to (Y-56), (Y-61), (Y-64) to (Y-66), (Y-69), (Y-72), (Y-76), (Y-81), (Y -156), (Y-159), (Y-160), (Y-161), (Y-162), (Y-168), (Y-169), (Y-170), (Y-171) ), (Y-173), (Y-175), and (Y-178) to (Y-182) are preferable.

<Production of polyimide precursor-polyamic acid>

The polyamic acid which is a polyimide precursor used for this invention can be manufactured with the following method.

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

Reaction of a diamine component and a tetracarboxylic-acid component is normally performed in a solvent. As a solvent used in that case, if the produced|generated polyimide precursor melt|dissolves, it will not specifically limit. Although the specific example of the solvent used for reaction is given below, it is not limited to these examples. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, or 1,3-dimethyl-imidazolidinone.

Moreover, when solubility of a polyimide precursor is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a following formula [D-1] - a formula [D -3] can be used.

[Formula 35]

Of the formula ^[D-1], D 1 represents an alkyl group having a carbon number of 1 to 3, wherein ^[D-2], D 2 represents an alkyl group having a carbon number of 1 to 3, formula ^[D-3], D 3 represents a C1-C4 alkyl group.

These solvents may be used independently and may be mixed and used. Moreover, even if it is a solvent in which a polyimide precursor is not dissolved, you may use it in the range in which the produced|generated polyimide precursor does not precipitate, mixing with the said solvent. Moreover, since the water|moisture content in a solvent inhibits a polymerization reaction and becomes a cause to hydrolyze the produced|generated polyimide precursor by extension, it is preferable to use the solvent which carried out dehydration and drying.

From the point that polymer precipitation does not occur easily and it is easy to obtain a high molecular weight body, 1-30 mass % is preferable and, as for the density|concentration of the polyamic-acid polymer in a reaction system, 5-20 mass % is more preferable.

When introduce|transducing a silylating agent during and after superposition|polymerization of a polyimide precursor, 25-100 mol% is preferable with respect to the amount of carboxylic acid in a polyimide precursor, and, as for the introduction amount, it is especially preferable that it is 75-100 mol%. . After introduction of the silylating agent, a silylated polyimide precursor is obtained by stirring at 5°C to 60°C, preferably at 40°C to 80°C, for 1 to 30 hours, preferably 6 to 24 hours.

In addition, in order to prevent oxidation of the diamine moiety in a polyamic acid, it is preferable to nitrogen-substitute the inside of a system during reaction, and in order not to change the temperature in a system, it is preferable to provide a reflux device.

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

<Polyimide>

The polyimide used for this invention can be manufactured by imidating an above-described polyamic acid or polyamic acid ester.

Moreover, when imidating the polyamic acid which is not silylated by the method mentioned later, melt|dissolving the imidation polymer isolated in a solvent, and manufacturing a liquid crystal aligning agent, it can manufacture also by introduce|transducing a silylation agent.

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 a decrease in the molecular weight of the polymer hardly occurs during the imidization process.

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

The temperature at the time of imidation reaction is -20-140 degreeC, Preferably it is 0-100 degreeC, and reaction time is 1-100 hours, Preferably it can carry out in 1-5 hours.

The quantity of a basic catalyst is 0.5-30 mole times of an amic acid group, Preferably it is 2-20 mole times, and the quantity of an acid anhydride is 1-50 mole times of an amic acid group, Preferably it is 3-30 mole times. The imidation rate of the polymer obtained is controllable by adjusting a catalyst amount, temperature, reaction time, etc.

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 a solvent is simple. Chemical imidization is preferable because the imidation reaction proceeds at a relatively low temperature, and a decrease in the molecular weight of the polymer hardly occurs during the imidization process.

Chemical imidation can be performed by stirring polyamic acid ester to be imidated in presence of a basic catalyst in a solvent. As a solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, 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 -20-140 degreeC, Preferably it is 0-100 degreeC, and reaction time is 1-100 hours, Preferably it can carry out in 1-5 hours.

The quantity of a basic catalyst is 0.5-30 mole times of an amic acid ester group, Preferably it is 2-20 mole times.

The imidation rate of the polymer obtained is controllable by adjusting a catalyst amount, temperature, reaction time, etc.

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 described below, to make it melt|dissolve again in a solvent, and to set it as the liquid crystal aligning agent of this invention.

In addition, in imidation reaction of a polyamic acid or polyamic acid ester, an imidation accelerator can be used. Although the specific example of an imidation promoter is shown below, it is not limited to these.

[Formula 36]

D in the formulas (B-1) to (B-17) is each independently a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group. A plurality of Ds present in the formulas (B-14) to (B-17) may be the same as or different from each other. The imidation promoting effect of polyamic acid ester and polyamic acid becomes still higher, so that the basicity after deprotection by heating becomes high. Therefore, (B-14)-(B-17) are preferable at the point which improves the thermal imidation acceleration|stimulation effect more, and (B-17) is especially preferable especially.

Since the catalyst etc. which added remain in the solution after imidation reaction of polyamic acid or polyamic acid ester, the obtained imidation polymer is collect|recovered by the means described below, it is made to melt|dissolve again in a solvent, and liquid crystal orientation of this invention It is preferable to set it to zero.

A polymer can be deposited by inject|pouring into the following 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, it can be made to room temperature or heat-dry, and the powder of the refined polyamic acid ester can be obtained.

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

When re-dissolving the obtained polyimide powder in a solvent, a solvent (it is also mentioned a good solvent) will not be specifically limited if a specific structural polymer melt|dissolves uniformly. For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, or 4-hydroxy-4-methyl-2-pentanone, etc. are mentioned.

Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

As for the temperature at the time of re-dissolution, 5 degreeC - 80 degreeC are preferable, More preferably, they are 20 degreeC - 50 degreeC. As for the stirring time of re-dissolution, 30 minutes - 50 hours are preferable, More preferably, they are 3 hours - 12 hours.

When re-dissolving the polyimide powder which is not silylated, a silylated polyimide solution can be obtained by introduce|transducing a silylating agent during stirring at the time of re-dissolution. After introduction of the silylating agent, a silylated polyimide solution is obtained by stirring at 5°C to 60°C, preferably at 40°C to 80°C, for 1 to 30 hours, preferably 6 to 24 hours.

<Liquid crystal aligning agent>

The liquid crystal aligning agent used for this invention has the form of the solution which melt|dissolved in the at least 1 sort(s) chosen from the polyamic acid and polyimide which have a structure of said Formula (1) in a solvent.

As for the molecular weight of a specific structural polymer, 2,000-500,000 are preferable in terms of 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 in the liquid crystal aligning agent of this invention can be suitably changed with setting of the thickness of the coating film to be formed, from the point of forming a uniform and defect-free coating film, it is preferable that it is 1 mass % or more, and of a solution It is preferable to set it as 10 mass % or less from the point of storage stability. Especially preferably, it is 3-6.5 mass %.

The solvent (it is also mentioned a good solvent) contained in the liquid crystal aligning agent of this invention will not be specifically limited if a specific structural polymer melt|dissolves uniformly.

For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, or 4-hydroxy-4-methyl-2-pentanone, etc. are mentioned.

Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

Moreover, when the solubility with respect to the solvent of the polymer of this invention is high, it is preferable to use the solvent shown by the said Formula [D-1] - a formula [D-3].

It is preferable that the good solvent in the liquid crystal aligning agent of this invention is 20-99 mass % of the whole solvent contained in a liquid crystal aligning agent. Especially, 20-90 mass % is preferable. More preferably, it is 30-80 mass %.

The liquid crystal aligning agent of this invention can use the solvent (it is also mentioned a poor solvent) which improves the coating-film property and surface smoothness of the liquid crystal aligning film at the time of apply|coating a liquid crystal aligning agent, unless the effect of this invention is impaired. Although the specific example of a poor solvent is given below, it is not limited to these examples.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, Isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1- Butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methyl Cyclohexanol, 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 diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl Ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl Acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-( Hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1-(butoxyethoxy) propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether , Dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol di Acetate, diethylene glycol monoethyl ether acetate Diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, lactic acid Ethyl, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3- Ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionic acid butyl, lactic acid methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, The solvent etc. which are shown by said formula [D-1] - a formula [D-3] are mentioned.

Among them, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether is preferably used.

It is preferable that it is 1-80 mass % of the whole solvent contained in a liquid crystal aligning agent, as for a poor solvent, 10-80 mass % is more preferable, 20-70 mass % is more preferable.

In the liquid crystal aligning agent of this invention, as long as it is a range in which the effect of this invention is not impaired other than the above, polymers other than the polymer of this invention, the dielectric constant for the purpose of changing electrical properties, such as dielectric constant and electroconductivity of a liquid crystal aligning film, or an electrically-conductive substance , a silane coupling agent for the purpose of improving the adhesion between the liquid crystal aligning film and the substrate, a crosslinkable compound for increasing the hardness and density of the film when it is used as a liquid crystal aligning film, and furthermore, when firing the coating film, You may add an imidation accelerator etc. for the purpose of advancing de-ification efficiently.

<Liquid crystal alignment film>

<Liquid crystal display element>

Although the liquid crystal aligning film of this invention can be used for the liquid crystal aligning film of a horizontal alignment type or a vertical alignment type, especially, it is a liquid crystal aligning film suitable for vertical alignment type liquid crystal display elements, such as a VA system or a PSA mode. As a formation method of the liquid crystal aligning film of this invention, first, the said liquid crystal aligning agent is apply|coated to a board|substrate, it dries, it bakes, and obtains a coating film. It will not specifically limit if it is a board|substrate with high transparency as a board|substrate which apply|coats the liquid crystal aligning agent of this invention, Plastic substrates, such as a glass substrate, a silicon nitride board|substrate, an acryl board|substrate, a polycarbonate board|substrate, etc. can be used. Moreover, it is preferable from the point of simplification of a process to use the board|substrate with which the ITO electrode etc. for a liquid-crystal drive were formed. Moreover, in a reflection type liquid crystal display element, if it is only one side board|substrate, even if it is opaque, such as a silicon wafer, it can be used, and a material which 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, the spin coat method, the printing method, the inkjet method, etc. are mentioned. 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 solvent contained, it is 50-120 degreeC, Preferably it is 60-100 degreeC, 1 to 10 minutes, Preferably it is 2 to 5 minutes, It is dried, 150-300 degreeC after that, Preferably it is 200-240 degreeC, for 5-120 minutes, Preferably it bakes for 10 to 30 minutes. Although the thickness of the coating film after baking is not specifically limited, Since the reliability of a liquid crystal display element may fall when it is too thin, it is 5-300 nm, Preferably it is 10-200 nm.

Although the coating film formed above can be used as a liquid crystal aligning film as it is, you may orientation-process with respect to this coating film. As a method of orientation-processing, the rubbing method, the photo-alignment process method, etc. are mentioned.

A rubbing process can be implemented using an existing rubbing apparatus. Cotton, nylon, rayon, etc. are mentioned as a material of the rubbing cloth at this time. Generally, as conditions of a rubbing process, the conditions of a rotation speed of 300-2000 rpm, a feed rate of 5-100 mm/s, and 0.1-1.0 mm of press-in amount are used. Thereafter, residues generated by rubbing are removed by ultrasonic cleaning using pure water, alcohol, or the like.

A photo-alignment process WHEREIN: As a radiation irradiated to a coating film, the ultraviolet-ray and visible light containing the light of a wavelength of 150-800 nm can be used, for example. When the radiation is polarized light, it may be linearly polarized or partially polarized. In the case where the radiation to be used is linearly polarized light or partially polarized light, irradiation may be performed from a direction perpendicular to the substrate surface, may be performed from a diagonal direction, or a combination thereof may be performed. When irradiating unpolarized radiation, the direction of irradiation is made into a diagonal direction.

Next, the liquid crystal display device of the present invention can be manufactured by any of the following steps (1), a combination of steps (2) and (4), or a combination of steps (3) and (4). have.

(1) In case of VA type liquid crystal display device

Two board|substrates with a liquid crystal aligning film are prepared as mentioned above, and a liquid crystal is arrange|positioned between two board|substrates opposingly arranged. Specifically, the following two methods are mentioned. The first method is a method known conventionally. First, two board|substrates are opposingly arrange|positioned through the clearance gap (cell gap) so that each liquid crystal aligning film may oppose. Next, the periphery of the board|substrate of 2 sheets is bonded together using a sealing compound, after injecting-filling the liquid crystal composition in the cell gap partitioned by the board|substrate surface and the sealing compound, and making it contact a film surface, an injection hole is sealed.

The second method is a method called an ODF (One Drop Fill) method. For example, an ultraviolet-ray-curable sealing compound is apply|coated to the predetermined place on one board|substrate among the board|substrates of 2 sheets in which the liquid crystal aligning film was formed, and a liquid crystal composition is further dripped at predetermined various points on the liquid crystal aligning film surface. Then, the other board|substrate is bonded together so that a liquid crystal aligning film may oppose, a liquid crystal composition is pressed and spread on the whole surface of a board|substrate, and it is made to contact a film surface. Next, ultraviolet light is irradiated to the whole surface of a board|substrate, and a sealing compound is hardened. Also in the case of any method, it is preferable to remove the flow orientation at the time of liquid-crystal filling by further heating to the temperature which the used liquid-crystal composition takes an isotropic phase, and cooling it to room temperature.

(2) In the case of manufacturing a PSA type liquid crystal display device

It is carried out similarly to said (1) except the point which inject|pours or drips the liquid-crystal composition containing a polymeric compound. As a polymeric compound, the polymeric compound represented, for example by following formula (M-1) - (M-7) is mentioned.

[Formula 37]

(3) When a coating film is formed on a substrate using a liquid crystal aligning agent containing a compound having a polymerizable group

After carrying out similarly to said (1), you may employ|adopt the method of manufacturing a liquid crystal display element through the process of irradiating the ultraviolet-ray mentioned later. According to this method, similarly to the case of manufacturing the PSA type liquid crystal display element, a liquid crystal display element excellent in response speed can be obtained with a small amount of light irradiation. The compound having a polymerizable group may be a compound having at least one polymerizable unsaturated group in a molecule such as an acrylate group or a methacrylate group represented by the formulas (M-1) to (M-7), and the content thereof is all It is preferable that it is 0.1-30 mass parts with respect to 100 mass parts of polymer components, More preferably, it is 1-20 mass parts. Moreover, the polymer used for the polymer composition may have the said polymeric group, and as such a polymer, the polymer obtained by using for reaction the diamine component containing the diamine which has a photopolymerizable group at the terminal is mentioned, for example. .

(4) Step of irradiating ultraviolet rays

The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films included in the pair of substrates obtained in (2) or (3) above. The voltage to be applied here can be, for example, 5 to 50 V of direct current or alternating current. Moreover, although the ultraviolet-ray and visible light containing the light of a wavelength of 150-800 nm can be used as light to irradiate, The ultraviolet-ray containing the light of a wavelength of 300-400 nm is preferable, for example. As a light source of irradiation light, a low pressure mercury lamp, a high pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser etc. can be used, for example. As an irradiation amount of light, Preferably it is 1,000-200,000 J/m<2>, More preferably, it is 1,000-100,000 J/m<2>.

And a liquid crystal display element can be obtained by bonding a polarizing plate to the outer surface of a liquid crystal cell. As a polarizing plate bonded to the outer surface of the liquid crystal cell, a polarizing plate formed by sandwiching a polarizing film called "H film" in which iodine is absorbed while stretching or aligning polyvinyl alcohol with a cellulose acetate protective film, or a polarizing plate composed of the H film itself. have.

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

Example

The present invention will be more specifically described below by way of Examples. However, the present invention should not be construed as being limited to these Examples. The abbreviation of the compound used is shown below.

(specific diamines)

DBA: 3,5-diaminobenzoic acid

3AMPDA: 3,5-diamino-N-(pyridin-3-ylmethyl)benzamide

DA-1: A compound represented by the formula [DA-1] (diamine having a specific side chain structure)

[Formula 38]

(Tetracarboxylic acid component)

PMDA: pyromellitic anhydride

Compounds represented by the following [D1] to [D2]

D1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride

D2: bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride

(silylating agent component)

Compounds represented by the following formulas [S-1] to [S-5] (silylating agent)

[Formula 39]

(menstruum)

NMP: N-methyl-2-pyrrolidone

BCS: Ethylene glycol monobutyl ether

<Measurement of molecular weight of polyimide>

The molecular weight of the polyimide in the synthesis example was as follows using the normal temperature gel permeation chromatography (GPC) apparatus (SSC-7200) by the Senshu Scientific company, and the column (KD-803, KD-805) by the Shodex company. It was measured together.

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 samples for calibration curve preparation: TSK standard polyethylene oxide (molecular weights about 9,000,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol manufactured by Polymer Laboratories (molecular weights of about 12,000, 4,000, 1,000).

<Measurement of imidization rate>

The imidation ratio of the polyimide in a synthesis example was measured as follows. 20 ㎎ the polyimide powder NMR sample tube and into the (Kusano Science manufacture NMR sample tube Standard φ5), the addition of 0.53 ㎖ deuterated dimethyl sulfoxide (DMSO-d _6, TMS 0.05% mixed product), and completely dissolved.

Proton NMR of 500 MHz was measured for this solution with the NMR measuring instrument (JNW-ECA500) manufactured by Nippon Electronics Datum Co., Ltd. The imidation rate is determined using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integration value of this proton and the proton peak integration derived from the NH group of the amic acid appearing around 9.5 to 10.0 ppm. It calculated|required by the following formula using a value.

Imidization rate (%) = (1-α·x/y) × 100

<Synthesis of polyimide-based polymer>

<Synthesis Example 1>

In a 100 ml four-neck flask equipped with a stirring device and a nitrogen inlet tube, 2.74 g (18.0 mmol) of DBA, 3.27 g (13.5 mmol) of 3AMPDA, and 5.14 g (13.5 mmol) of DA-1 were weighed and placed, solid content It diluted with NMP so that a density|concentration might be set to 20%. After 30 minutes of room temperature stirring, 2.25 g (8.99 mmol) of D2 was added, it diluted with NMP again so that it might become solid content concentration 20%, and it heat-stirred at 60 degreeC for 1 hour. After cooling the obtained reaction liquid to 17 degrees C or less, 1.96g (8.99mmol) of PMDA was added, and it stirred at room temperature after dilution with NMP20% for 5 hours. Finally, D1 was diluted with 5.11 g (26.1 mmol) NMP so that it might become a solid content concentration of 20%, and it heat-stirred at 40 degreeC for 6 hours. Polyamic acid polymerization liquid (PAA-1) was obtained by cooling the obtained polymerization liquid to room temperature.

<Synthesis Example 2>

After adding NMP (103.85 g) to PAA-1 (50.0 g) and diluting to 6.5 mass %, acetic anhydride (6.67 g) and pyridine (2.58 g) are added as an imidation catalyst, and 70 degreeC for 3 hours. reacted. This reaction solution was poured into methanol (570.9 g), and the obtained precipitate was separated by filtration. Methanol wash|cleaned this deposit, it dried under reduced pressure at 60 degreeC, and the polyimide powder (SPI-1) of the synthesis example 1 was obtained. The imidation ratio of this polyimide was 72 %, the number average molecular weight was 11,800, and the weight average molecular weight was 41,800.

<Synthesis Example 3>

After adding 1.75g of S-1 to PAA-1 (10.0g), the polyamic-acid silyl ester polymerization liquid was obtained by heat-stirring at 50 degreeC for 12 hours (PASE-1).

<Synthesis Example 4-7>

Polyamic acid silyl ester polymerization liquid was obtained by the process similar to Synthesis Example 3 in all except having added the quantity in the following table instead of S-1 in Synthesis Example 3 S-2 to S-5 (PASE-2 ~ PASE-5).

<Example 1>

NMP (14.0 g) and BCS (8.0 g) were added to the polyamic acid silyl ester polymerization liquid (PASE-1) (6.0 g) obtained in the synthesis example 3, and it stirred at 25 degreeC for 5 hours. Thereby, the liquid crystal aligning agent [1] of Example 1 was obtained. Abnormalities, such as turbidity and precipitation, were not seen by this liquid crystal aligning agent, but it was confirmed that the resin component is melt|dissolving uniformly.

<Example 2-5>

NMP (14.0g) and BCS (8.0g) were added to the polyamic-acid silyl ester polymerization liquid (PASE-2 - PASE-5) (6.0g) obtained by the synthesis example 4-7, and it stirred at 25 degreeC for 5 hours. Thereby, the liquid crystal aligning agent [2-5] of Example 2-5 was obtained. Abnormalities, such as turbidity and precipitation, were not seen by this liquid crystal aligning agent, but it was confirmed that the resin component is melt|dissolving uniformly.

<Comparative Example 1>

NMP (14.0 g) and BCS (8.0 g) were added to the polyamic acid polymerization liquid (PAA-1) (6.0 g) obtained in the synthesis example 1, and it stirred at 25 degreeC for 5 hours. Thereby, the liquid crystal aligning agent of the comparative example 1 was obtained. Abnormalities, such as turbidity and precipitation, were not seen by this liquid crystal aligning agent, but it was confirmed that the resin component is melt|dissolving uniformly.

<Production of liquid crystal cell>

The liquid crystal aligning agent obtained above is spin-coated on the ITO surface of the alkali-free-glass board|substrate with ITO (30 mm in length, 40 mm in width, 0.7 mm in thickness) wash|cleaned with pure water and IPA (isopropyl alcohol), respectively, and 70 degreeC After baking on a hotplate for 90 seconds, baking was performed for 20 minutes in a 230 degreeC infrared heating furnace, and the polyimide coating board|substrate with a film thickness of 100 nm was manufactured.

Two polyimide-coated board|substrates were manufactured by the said method, and after spread|dispersing a 4 micrometers bead spacer on the liquid crystal aligning film surface of one board|substrate, a thermosetting sealing compound (XN-1500T made by Kyoritsu Chemical Co., Ltd.) was printed from it. . Next, after turning inside the surface of the side in which the liquid crystal aligning film of the other board|substrate was formed and bonding together with the previous board|substrate, the sealing compound was hardened and the empty cell was manufactured. The liquid crystal cell containing the polymeric compound for PSA MLC-3023 (made by Merck Corporation) was inject|poured into this empty cell by the reduced pressure injection method, and the liquid crystal cell was manufactured. The voltage retention of this liquid crystal cell was measured.

Next, in the state which applied the DC voltage of 15V to this liquid crystal cell, 7 J/cm<2> irradiation (it is also called primary PSA process) was carried out with UV which passed the 325 nm cut-off filter from the outer side of this liquid crystal cell. In addition, UV illuminance was measured using UV-MO3A by ORC.

Thereafter, for the purpose of inactivating the unreacted polymerizable compound remaining in the liquid crystal cell, UV (UV lamp: FLR40SUV32/A-) was used using a UV-FL irradiation device manufactured by Toshiba Lightek in a state where no voltage was applied. 1) was irradiated for 30 minutes (referred to as secondary PSA treatment). Then, the voltage retention was measured.

<Evaluation of voltage retention>

Using the liquid crystal cell prepared above, after applying a voltage of 1 V for 60 μs in a hot air circulation oven at 60 ° C., and then measuring the voltages after 16.67 msec and 1667 msec, respectively, to determine how much the voltage is maintained It was calculated as voltage retention. For the measurement of the voltage retention, VHR-1 manufactured by Toyo Technica Corporation was used.

As shown in the table, PASE obtained by silyl esterification with a silylating agent showed good voltage retention relative to Comparative Examples, and in particular, PASE-1 and PASE-2 having a Tert-Butyl group had good voltage retention.

<Evaluation of solubility>

1 g of the liquid crystal aligning agent of Example 3-7 and the comparative example 1 obtained above were dripped, respectively, BCS was dripped, respectively, and solubility was computed by the following formula from the weight to be cloudy.

An evaluation result is shown in the following table|surface.

Solubility = (amount of BCS in liquid crystal aligning agent + amount of dripping BCS)/(amount of liquid crystal aligning agent + amount of dripping BCS)

Industrial Applicability

Although the liquid crystal aligning film obtained from the liquid crystal aligning agent of this invention is using a polyamic acid, it has reliability equal or more than a soluble polyimide, specifically, high voltage retention characteristic. Therefore, the use in the wide liquid crystal display element by which high display quality is calculated|required is possible.

Claims (7)

The liquid crystal aligning agent containing at least 1 sort(s) of the polyamic acid which has a structure of following formula (1), and a polyimide.

In the formula, R ₁ represents a trialkylsilyl group. The method of claim 1,
_{The liquid crystal aligning agent whose R<1>} of said Formula (1) is t-butylsilyl group. 3. The method according to claim 1 or 2,
The liquid crystal aligning agent whose said polyamic acid is a reaction product of a polyamic acid and a silylating agent. 4. The method of claim 3,
The liquid crystal aligning agent whose said silylating agent is at least 1 sort(s) chosen from following (S-1)-(S-5).

5. The method according to any one of claims 1 to 4,
The said polyamic acid and polyimide are obtained from reaction of a tetracarboxylic-acid derivative and diamine, The said tetracarboxylic-acid derivative is tetracarboxylic dianhydride represented by following formula (3), The liquid-crystal orientation characterized by the above-mentioned My.

(X ₁ represents a tetravalent organic group) The liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of Claims 1-5. A liquid crystal display element provided with the liquid crystal aligning film of Claim 6.