JP5857097B2 - Diaminobenzene compound, polymer, composition for alignment film, alignment film, and liquid crystal display device - Google Patents

Description

The present invention relates to a diamine compound, and in particular, a diaminobenzene compound, a polymer having an amide bond and / or an imide bond produced by the diaminobenzene compound, an alignment film composition containing the polymer, and the alignment The present invention relates to an alignment film produced using a film composition, and a liquid crystal display device including the alignment film.

The principle of operation of a liquid crystal display is that an external electric field is used to change the alignment state of liquid crystal molecules, thereby causing a change in the polarization state and direction of light, thereby obtaining a brightness and contrast display effect. In recent years, liquid crystal displays have become mainstream of flat displays because they have advantages such as small size, light weight, low power consumption, and excellent display quality.

With the expansion of the screen size, a liquid crystal display device having a thin film transistor (TFT) in each pixel has been developed. When liquid crystal molecules are arranged between a pair of substrates having electrodes, the liquid crystal molecules have different dielectric constants in parallel and perpendicular molecular directions, and thus the arrangement method of liquid crystal molecules can be controlled by controlling the electric field. In addition, since the liquid crystal molecules have birefringence characteristics, the polarization direction of polarized light can be adjusted by changing the alignment state of the liquid crystal molecules.

A single-layer alignment film is coated on the substrate so that the liquid crystal molecules have a uniform tilt angle and a certain orientation on the substrate, and the alignment direction of the liquid crystal molecules is controlled by this alignment film, thereby stabilizing the liquid crystal molecules. Provide tilt angle. In addition, when the external electric field is turned off, the liquid crystal molecules return to the original alignment due to the anchoring force with the alignment film interface and its own elasticity.

Currently, a typical method for producing an alignment film in the industrial field is to place the organic thin film on the surface of the substrate and arrange it later by rubbing or otherwise orienting the molecules on the surface of the thin film in a certain direction. The liquid crystal molecules are tilted in a certain direction. The material of the organic thin film can be selected from polyvinyl alcohol, polyethylene glycol, polyamide, polyamic acid or polyimide, and the polyamic acid and polyimide have excellent thermal stability and good mechanical, electrical and chemical resistance. Therefore, it is often used as a material for the alignment film. Polyamic acid is a polymer obtained by polymerization reaction of diamine and tetracarboxylic acid, or diamine and tetracarboxylic dianhydride, and polyimide is generally subjected to dehydration ring closure reaction (imidation ( imidization)).

The voltage holding ratio is related to a situation in which the voltage gradually decreases while the liquid crystal display element is in an open circuit state. The active matrix driving liquid crystal display element will be described. When a certain pixel is temporarily not displayed on the screen, the circuit of this pixel enters an open circuit state and starts discharging. If the voltage holding ratio of this device is not high, the voltage value between the electrodes will decrease instantaneously, causing the orientation of the liquid crystal molecules to be confused and causing image defects. Is a very important indicator and must be high and uniform.

The present invention is produced using a diaminobenzene compound, a polymer having an amide bond and / or an imide bond produced by the diaminobenzene compound, an alignment film composition containing the polymer, and the alignment film composition. An alignment film and a liquid crystal display device including the alignment film are provided. Since the diaminobenzene compound has high polarity, the liquid crystal display device has an excellent voltage holding ratio.

The diaminobenzene compound of the present invention is represented by the formula (1):

...... Formula (1)

In the formula, Ar is represented by the formula (2):

...... Formula (2)

In the formula, * is a position where the group represented by the formula (2) is bonded to two —NH ₂ of the formula (1);
Each R ₁ is independently a hydrogen atom or a monovalent substituent other than a primary amine;
X ₁ is
Or
A divalent linking group comprising:
R ₂ is a divalent linking group containing a benzene ring or a cyclohexane ring, in which hydrogen on the benzene ring or cyclohexane ring is independently an alkyl group having 1 to 3 carbon atoms, F, Cl, —OH or — May be replaced by CN;
X ₂ and X ₃ are each a linear alkylene group having 1 to 3 carbon atoms;
R ₃ is a monovalent substituent containing a benzene ring or a cyclohexane ring, in which hydrogen on the benzene ring or cyclohexane ring is independently an alkyl group having 1 to 3 carbon atoms, F, Cl, —OH or — It may be replaced by CN.

In one embodiment of the invention, R ₂ is an aromatic group.

In one embodiment of the invention, R ₂ is a group represented by formula (3):

...... Formula (3)

Wherein, Q ₁ to Q ₄ are each hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In one embodiment of the invention, R ₃ is a group represented by formula (4):

...... Formula (4)

In the formula, Q _{5 to} Q ₉ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In one embodiment of the present invention, the diaminobenzene compound is represented by formula (5):

...... Formula (5)

The polymer having an amide bond, an imide bond or the above-described two kinds of bonds of the present invention includes a unit represented by any one of formulas (6) to (9):

...... Formula (6)
...... Formula (7)
...... Formula (8)
...... Formula (9)

Where
G ₁ is an aliphatic tetracarboxylic acid residue, alicyclic tetracarboxylic acid residue or aromatic tetracarboxylic acid residue having 2 to 30 carbon atoms,
G ₂ is an aliphatic tricarboxylic acid residue, alicyclic tricarboxylic acid residue or aromatic tricarboxylic acid residue having 2 to 30 carbon atoms,
G ₃ is an aliphatic dicarboxylic acid residue, alicyclic dicarboxylic acid residue or aromatic dicarboxylic acid residue having 2 to 30 carbon atoms,
Each R ₄ is independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms;
Ar in the formulas (6) to (9) is a residue of the diaminobenzene compound described above.

In one embodiment of the present invention, the ratio of the unit represented by any one of formulas (6) to (9) in the polymer is 5 mol% to 99 mol%.

The composition for an alignment film of the present invention includes the polymer having the amide bond, the imide bond, or the two kinds of bonds described above.

The alignment film of the present invention is manufactured by the alignment film composition described above.

The liquid crystal display element of the present invention includes the alignment film described above.

As described above, the present invention uses a diaminobenzene compound, a polymer having an amide bond and / or an imide bond produced thereby, an alignment film composition containing the polymer, and the alignment film composition. An alignment film and a liquid crystal display device are provided. Since the diaminobenzene compound has a high polarization parameter, the liquid crystal display element has an excellent voltage holding ratio and can effectively solve the afterimage problem of the liquid crystal display element.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, several embodiments are described below.

It is a NMR spectrum photograph of the product of each step in a synthesis example. It is a NMR spectrum photograph of the product of each step in a synthesis example. It is a NMR spectrum photograph of the product of each step in a synthesis example. It is a NMR spectrum photograph of the product of each step in a synthesis example.

Hereinafter, the present invention will be further described with reference to examples. In this specification, unless specified otherwise whether a group is substituted, the group may represent a substituted or unsubstituted group. For example, the “alkyl group” may be a substituted alkyl group or an unsubstituted alkyl group. Further, when a group is depicted by “C _x ”, this indicates that the main chain of the group has X carbon atoms.

In the text, sometimes the structure of a compound is represented by a skeleton formula. This type of display method can omit carbon atoms, hydrogen atoms and carbon-hydrogen bonds. Of course, when the functional group is clearly depicted in the structural formula, the description is based on the description.

In the present specification, the range indicated by “a numerical value from another numerical value” is a general display method for avoiding mentioning all the numerical values within the range one by one in the specification. Accordingly, the description of a specific numerical range simultaneously discloses any numerical value within the numerical range and a relatively small numerical range limited by any numerical value within the numerical range. The numerical value and the relatively small numerical range are the same as specified. For example, the range of “temperature of 80 ° C. to 300 ° C.” includes the range of “temperature of 100 ° C. to 250 ° C.” regardless of whether other numerical values are listed in the specification.

The first embodiment of the present invention provides a diaminobenzene compound represented by the formula (1):

...... Formula (1)

Ar is a residue of the diaminobenzene compound represented by the formula (1), and is represented by the formula (2):

...... Formula (2)

Where
* Is a position where the group represented by the formula (2) is bonded to two —NH ₂ of the formula (1).

In this embodiment, each R ₁ may independently be a hydrogen atom or a monovalent substituent other than a primary amine; X ₁ is
Or
R ₂ may be a divalent linking group containing a benzene ring or a cyclohexane ring, in which the hydrogen of the benzene ring or cyclohexane ring is independently a carbon number 1 to 3 alkyl groups, F, Cl, —OH or —CN may be substituted; X ₂ and X ₃ are each a straight-chain alkylene group having 1 to 3 carbon atoms such as an ethylene group, R ₃ may be a monovalent substituent containing a benzene ring or a cyclohexane ring, in which the hydrogen of the benzene ring or cyclohexane ring is independently an alkyl group having 1 to 3 carbon atoms, F, It may be substituted by Cl, -OH or -CN.

In the present embodiment, when the alkyl group is substituted, it is more preferably substituted with fluorine.

A polymer having an amide bond and / or an imide bond using the above-mentioned diaminobenzene compound can be produced by a well-known method, and this type of polymer is often used for producing an alignment film of a liquid crystal display device. From this point of view, the ring structure of two nitrogen atoms contained in the diaminobenzene compound adsorbs impurities at the interface of the alignment film, so that the electrical characteristics can be improved; and the ring bond is five-membered or In the case of a six-membered ring, the orientation of the alignment film can be improved. That is, X ₂ and X ₃ in the formula (2) are preferably ethylene groups at the same time, or more preferably one is a methylene group and the other is an ethylene group. Further, X ₁ in the formula (2) can increase the voltage holding ratio of the liquid crystal display element because the diaminobenzene compound has high polarity.

In the present embodiment, R ₂ may be an aromatic group, for example, a group represented by the formula (3):

...... Formula (3)

Wherein, Q ₁ to Q ₄ are each, for example, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In the present embodiment, R ₃ may be an aromatic group, and is represented by, for example, formula (4).

...... Formula (4)

In the formula, Q _{5 to} Q ₉ are each, for example, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

If it demonstrates concretely, the diaminobenzene compound of this embodiment is represented by Formula (5).

...... Formula (5)

The diaminobenzene compound in the present embodiment can be obtained by synthesis in the following two steps.

First, in the presence of an alkali and an organic solvent, a dinitrobenzene compound represented by formula (I) and a piperazine compound represented by formula (II) are subjected to a substitution reaction to obtain a compound represented by formula (III). .

...... Formula (I)

...... Formula (II)

...... Formula (III)

In the formula, Y ₁ is, for example, —F, —Cl, —Br, —COCl, —COOH and similar groups; Y ₂ is, for example, —NH ₂ . When Y ₁ is —F, —Cl or —Br and Y ₂ is —NH ₂ , X ₁ obtained by the reaction of both is —NH—; Y ₁ is —COCl or —COOH, and When Y ₂ is —NH ₂ , X ₁ obtained by the reaction of both is —CONH—. For _{R 1 ~R 3, X 1 ~X} 3, are as defined for formula (2).

Subsequently, the compound represented by the formula (III) is subjected to a reduction reaction (hydrogenation reaction) to obtain a diaminobenzene compound represented by the formula (1).

In the synthesis method described above, the added alkali has a catalytic effect, so that the speed of the synthesis reaction can be increased and the reaction temperature can be lowered. The alkali to be applied may be an alkaline compound formed by Group IA and Group IIA metals, more preferably carbonates of Group IA and Group IIA metals. Alternatively, the alkali applied may be a tertiary amine (eg trimethylamine, triethylamine, triisopropylethylenediamine or similar compounds).

In this synthesis method, the organic solvent to be applied is an alkyl halide group (for example, dichloromethane, dichloroethane, chloroform or a similar compound), a ketone (for example, acetone, butanone or a similar compound), N-methyl-2-pyrrolidone, N, It may be N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide or similar compounds.

The above-described reduction reaction (hydrogenation reaction) may utilize a known hydrogenation reaction method. As an example, under a suitable pressure and temperature, a reduction reaction is performed with hydrogen gas or human azine using platinum (Pt), palladium (Pd), Raney nickel (Raney-Ni) or similar metal catalyst. be able to. By way of example, tin (II) chloride (SnCl ₂ ), iron (Fe) or similar reducing agents can be used to carry out the reduction reaction with concentrated hydrochloric acid. Alternatively, the reaction may be carried out in an aprotic solvent using LiAlH ₄ or a similar reducing agent.

The second embodiment of the present invention provides a polymer having an amide bond and / or an imide bond containing a repeating unit represented by any one of formulas (6) to (9).

...... Formula (6)
...... Formula (7)
...... Formula (8)
...... Formula (9)

In the present embodiment, G ₁ may be an aliphatic tetracarboxylic acid residue, alicyclic tetracarboxylic acid residue or aromatic tetracarboxylic acid residue having 2 to 30 carbon atoms, and G ₂ may be carbon It may be an aliphatic tricarboxylic acid residue, an alicyclic tricarboxylic acid residue or an aromatic tricarboxylic acid residue having 2 to 30 carbon atoms, and G ₃ is an aliphatic dicarboxylic acid residue having 2 to 30 carbon atoms, an It may be a cyclic dicarboxylic acid residue or an aromatic dicarboxylic acid residue, and each R ₄ may independently be a hydrogen atom or an alkyl group having 2 to 30 carbon atoms, Ar in the formula (9) is as defined in the formula (2).

The repeating unit represented by the formula (6) is generated, for example, by reacting the diaminobenzene compound of the first embodiment with tetracarboxylic acid or a dianhydride compound thereof. The repeating unit represented by the formula (7) is generated by dehydrating and cyclizing the repeating unit represented by the formula (6). The repeating unit represented by the formula (8) and the formula (9) can be generated by reacting the diamino compound of the first embodiment with a tricarboxylic acid, a dicarboxylic acid or a derivative thereof. Reactions such as reacting an amino group with an acidic group to form an amide bond, or dehydrating and cyclizing an amide bond to form an imide bond are well-known reactions to those skilled in the art. . Hereinafter, although the synthesis | combination of the repeating unit represented by Formula (6) and the repeating unit represented by Formula (7) is introduce | transduced a little, description is abbreviate | omitted for details.

The tetracarboxylic acid to be applied is not particularly limited. For example, an aromatic tetracarboxylic acid, an aliphatic cyclic tetracarboxylic acid, an aliphatic tetracarboxylic acid or a dianhydride thereof and a dicarboxylic acid diacid halide thereof may be used. Can be used. Tetracarboxylic acids may be used alone or in the form of a mixture of two or more.

Aromatic tetracarboxylic acids include, for example, 1,2,4,5-benzenetetracarboxylic acid, 3,3 ′, 4,4′-diphenyltetracarboxylic acid, 2,3,3 ′, 4-diphenyltetracarboxylic acid Bis (3,4-dicarboxyphenyl) ether, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, bis (3,4-dicarboxyphenyl) sulfoxide, bis (3,4-dicarboxyphenyl) Methane, 2,2-bis (3,4-dicarboxyphenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propane, bis (3,4-dicarboxyphenyl) dimethylsilane, bis (3,4-dicarboxyphenyl) diphenylsilane, 2,3,4,5-pyridinetetracarboxylic acid, 2,6- Scan is (3,4-carboxyphenyl) pyridine, diacid anhydride derived from an aromatic tetracarboxylic acid described above with a dicarboxylic diacid halides or the like.

Examples of the aliphatic cyclic tetracarboxylic acid include cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, cyclohexanetetracarboxylic acid, 1,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy-1,2,3, 4-tetrahydro-1-naphthalene succinic dianhydride, dianhydrides and dicarboxylic acid diacid halides or the like derived from the above-mentioned aliphatic cyclic tetracarboxylic acids.

Aliphatic tetracarboxylic acids are, for example, butanecarboxylic acid or derived dianhydrides and dicarboxylic acid diacid halides.

The polymerization method of the diaminobenzene compound and tetracarboxylic acid or its dianhydride compound is not particularly limited, and a known method can be used. For example, the diaminobenzene compound is first dissolved in an organic polar solvent (for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide). Subsequently, a tetracarboxylic acid or a dianhydride compound thereof is added to the solvent and a polymerization reaction is performed to obtain a polymer solution having an amide bond and / or an imide bond. The temperature at which the polymerization is performed is, for example, between −20 ° C. and 150 ° C., and more preferably between −5 ° C. and 100 ° C. The polymerization time is usually between 5 minutes and 24 hours, more preferably between 10 minutes and 8 hours.

The temperature at which the amide bond portion is heated and dehydrated and cyclized to form an imide bond is, for example, between 100 ° C. and 350 ° C., and more preferably between 120 ° C. and 320 ° C. The reaction time is, for example, between 3 minutes and 6 hours.

The relative ratio of the amide bond and the imide bond in the polymer can be controlled by the following two methods. The first is to control the ratio of the number of moles dehydrated; the second is to dehydrate and cyclize some diaminobenzene compounds and dianhydride compounds at a certain ratio, and then to leave the remaining diamino at room temperature. Polymerization is performed by adding a benzene compound and a dianhydride compound.

When the diaminobenzene compound of the first embodiment and a tetracarboxylic acid or its dianhydride compound are polymerized to produce a polymer having an amide bond and / or an imide bond, another diamine compound may be added at the same time. Good. This “other diamine compound” is not particularly limited, and may be an aromatic diamine compound, an aliphatic cyclic diamine compound, or an aliphatic diamine compound, for example.

Examples of the aromatic diamine compound include p-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, 2,2-diaminophenylpropane, bis (3,5-diethyl-4-aminophenyl) methane, diaminediphenylsulfone, diaminedibenzophenone, Diamine naphthalene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4-bis (4-aminophenoxy) diphenyl sulfone, 2,2-bis (4 , 4-aminophenoxyphenyl) propane, 2,2-bis (4-aminophenyl) hexafluoropropane and 2,2-bis (4,4-aminophenoxyphenyl) hexafluoropropane or the like.

The aliphatic cyclic diamine compound is, for example, bis (4-aminocyclohexyl) methane, bis (4-amino-3-methylcyclohexyl) methane or the like.

The aliphatic diamine compound is, for example, tetramethylene diamine or hexane diamine.

The other diamine compounds described above may be used alone or in the form of a mixture of two or more.

In other words, the polymer having an amide bond and / or an imide bond may further include a repeating unit other than the repeating unit represented by any one of the formulas (6) to (9). The ratio of the repeating unit represented by any one of the formulas (6) to (9) in the polymer is 5 mol% to 99 mol%, more preferably 30 mol% to It is 99 mol%, More preferably, it is 70 mol%-99 mol%.

In the present embodiment, the content of the diaminobenzene compound of the first embodiment is at least 1 mol%, more preferably at least 10 mol%, and still more preferably based on the total weight of the diamine compound used. At least 50 mol%.

The molar ratio of the tetracarboxylic acid or its dianhydride compound and the diaminobenzene compound for the polymer having an amide bond and / or an imide bond to have an appropriate molecular weight is, for example, between 0.8 and 1.2. . The closer the molar ratio of tetracarboxylic acid or its dianhydride compound and diaminobenzene compound is to 1, the higher the molecular weight and the higher the viscosity. When the molar ratio of tetracarboxylic acid or its dianhydride compound to diaminobenzene compound is less than 1, by adding an appropriate amount of end cap functional group, the molar ratio is not equal to 1 It is possible to reduce the occurrence of the oxidation phenomenon of the terminal functional group. Applicable end-capping functional groups are, for example, phthalic anhydride, maleic anhydride, aniline, cyclohexaneamine or the like.

After the polymerization reaction, the degree of polymerization of the obtained polymer having an amide bond and / or an imide bond is, for example, 10 to 5000, and more preferably 16 to 250. The weight average molecular weight is, for example, 5000 to 2500,000, and more preferably 8000 to 125,000.

In order to increase the degree of polymerization of the polymerization reaction and reduce the reaction time, a catalyst may be added during the reaction process. Applied catalysts are, for example, triethylamine, diethylamine, n-butylamine, pyridine and the like. In addition to the function of increasing the degree of polymerization and reducing the reaction time, the catalyst also has a function of adjusting the pH value of the solution.

The polymer having an amide bond and / or an imide bond formed by performing a polymerization reaction is more preferably between 10% by weight and 30% by weight with respect to the total weight of the solution.

3rd Embodiment of this invention provides the composition for alignment films containing the polymer and solvent which have the amide bond and / or imide bond of 2nd Embodiment of this invention.

In the present embodiment, the solvent of the alignment film composition may be an organic polar solvent, such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl. It may be caprolactam, dimethyl sulfoxide, γ-butyrolactone or the like.

Moreover, the composition for alignment films may further contain, for example, an organosilane (siloxane) compound, an epoxy compound, or a similar additive as necessary.

The organosilane (siloxane) compound is not particularly limited, and examples thereof include aminopropyltrimethoxysilane, aminopropyltriethylsilane, vinylmethylsilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-epoxypropyloxypropyltrimethoxysilane, 3-epoxypropyloxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, -Ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, N-bis (oxyethylene) -3-aminopropyltrimethoxysilane, N- Bis (oxyethylene) -3-aminopropyltriethylsilane or the like.

By properly controlling the content of the organosilane (siloxane) compound in the composition for the alignment film, the adhesion of the liquid crystal alignment film to the substrate surface is controlled under the condition that it does not affect the characteristics required of the liquid crystal alignment film. Can be improved. If the content of the organosilane (siloxane) compound in the alignment film composition is too large, the liquid crystal alignment film formed easily causes a phenomenon of alignment failure; the organosilane (siloxane) in the alignment film composition When the content of the compound is too small, the liquid crystal alignment film to be formed causes a phenomenon of poor rubbing resistance and excessive dust. Therefore, in this embodiment, the content of the organosilane (siloxane) compound is, for example, 0.01% by weight to 5% by weight with respect to the total weight of the polymer included in the alignment film composition, and more preferably, 0.1 wt% to 3 wt%.

The epoxy compound is not particularly limited, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexane glycol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentylglycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-m-phenylxylene, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, 3- (N-allyl-N-glycidyl) aminopropyltri Methoxysila , 3- (N, N- diglycidyl) may be aminopropyltrimethoxysilane.

By appropriately controlling the content of the epoxy compound in the alignment film composition, it is possible to improve the adhesion of the liquid crystal alignment film to the substrate surface on the condition that the characteristics required of the liquid crystal alignment film are not affected. it can. When the content of the epoxy compound in the alignment film composition is too large, the liquid crystal alignment film to be formed easily causes a phenomenon of alignment failure. If the content of the epoxy compound in the liquid crystal aligning agent is too small, the liquid crystal alignment film to be formed causes a phenomenon of poor rubbing resistance and excessive dust dust. Therefore, in this embodiment, content of an epoxy compound is 0.01 weight%-3 weight% with respect to the total weight of the composition for alignment films, for example, More preferably, 0.1 weight%-2 % By weight.

By adjusting the viscosity and solid content of the alignment film composition so as to be suitable for the subsequent processing process of the liquid crystal alignment film, the thickness and coating property of the formed alignment film can be controlled. As a method for adjusting the viscosity and the solid content, for example, the solid content is diluted with an organic solvent so that the solid content becomes 3 wt% to 10 wt%. In this embodiment, the organic solvent to be applied is N-methyl-2-pyrrolidone, m-cresol, γ-butyrolactone, N, N-dimethylacetamide, N, N-dimethylformamide or a mixture thereof. Alternatively, a solvent that cannot dissolve a polymer having an amide bond and / or an imide bond may be added on the condition that the solubility of the polymer having an amide bond and / or an imide bond does not deteriorate in other solvents. Such solvents include, for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether. ), Butyl carbitol, ethyl carbitol acetate, ethylene glycol or mixtures thereof. The content of such a solvent is more preferably controlled to 90% by weight or less with respect to the total weight of the solvent.

The fourth embodiment of the present invention provides an alignment film manufactured by the alignment film composition described in the third embodiment.

The alignment film is produced by the following steps: First, the polymer having an amide bond and / or imide bond of the present invention is dissolved in the above-mentioned organic polar solvent, and then a glass substrate or a transparent plastic film substrate having a transparent electrode. To coat. Subsequently, the solvent is heat-treated and evaporated at a temperature of 120 ° C. to 350 ° C. to form a thin film. The alignment film of this embodiment may be a liquid crystal alignment film that can provide a stable pretilt angle and high voltage holding ratio to liquid crystal molecules.

The fifth embodiment of the present invention provides a liquid crystal display device including the alignment film of the fourth embodiment of the present invention.

A liquid crystal display device is manufactured by the following steps: First, an alignment film composition obtained from a polymer having an amide bond and / or an imide bond is applied onto a glass substrate by a coating method, and then heated and baked. The organic solvent in the composition for alignment films is removed. Then, the polyamic acid that has not been cyclized (the repeating unit represented by the formula (6)) is promoted to undergo a dehydration / ring-closing reaction, thereby forming an alignment film.

The coating method is, for example, a roller coating method, a spin coating method, or a printing coating method.

The glass substrate may have a patterned transparent conductive film.

The temperature of the heating baking is, for example, between 80 ° C. and 300 ° C., and most preferably 100 ° C. to 240 ° C.

The thickness of the alignment film is more preferably 0.005 μm to 0.5 μm.

After forming the alignment film by heating baking, for example, by rubbing in a certain direction with a roller wrapped with nylon or cotton fiber cloth (twist nematic, TN), or without rubbing (vertical alignment, VA), The alignment film can provide alignment to the liquid crystal molecules.

Subsequently, a sealing agent is coated on the substrate having the alignment film, and a spacer is sprayed on the other substrate having the liquid crystal alignment film, and then the two alignment film substrates are perpendicular to each other's rubbing direction or A liquid crystal display device is preliminarily formed by combining in parallel and injecting liquid crystal into the gap between the two substrates to seal the injection hole. The manufacturing process for completing the subsequent liquid crystal display element is well known to those having ordinary knowledge in this field, and thus description thereof is omitted here.

The voltage holding ratio is used as an evaluation index of the liquid crystal display element. Voltage holding ratio measurement conditions: DC voltage (1 V or 5 V, 0.6 Hz, pulse width 60 μsec) is applied to the liquid crystal display element at an environmental temperature of 60 ° C., and the voltage holding ratio of the liquid crystal display element is measured.

<Experiment>

Hereinafter, the present invention will be described more specifically with reference to comparative examples and experimental examples, but the present invention is not limited to these experimental examples.

Synthesis example (synthesis of diaminobenzene compound)

First, 32.45 g of 1-phenylpiperazine was uniformly mixed in 170 g of tetrahydrofuran (THF), and 31.04 g of 1-fluoro-4-nitrobenzene (1-fluoro-nitrobenzene) was stirred while stirring. 4-nitrobenzene) was slowly added dropwise. The color of the solution changed from pale yellow to dark orange yellow, and the mixture was stirred for 12 hours to form a dark yellow precipitate, and then tetrahydrofuran (THF) was concentrated. The solid was placed in 510 g of isopropyl alcohol (IPA), washed and filtered, and the dark yellow product 1- (4-nitrophenyl) -4-phenylpiperazine (1- ( 4-nitrophenyl) -4-phenylpiperazine) was obtained. The 1H-NMR (d-DMSO) optical spectrum of the product is as shown in FIG. 1, and the structure is as follows.

Next, 56.67 g of 1- (4-nitrophenyl) -4-phenylpiperazine and 304.01 g of tetrahydrofuran (THF) were mixed and stirred, and 5.67 g of palladium-on-carbon, Pd / C) was added. 56.67 g of 70% hydrazine hydrate was slowly added dropwise using a tubing pump. The color of the solution changed from yellow to green and after stirring for 12 hours, it finally became a white clear liquid with a black suspension of Pd / C. Impurities were filtered through diatomaceous earth and concentrated to 200 g at 60 ° C., and the filtrate was immediately poured into 1216 g of n-hexane to obtain a white suspended solid. After filtration, a white solid was collected to obtain a white product of 4- (4-phenylpiperazin-1-yl) aniline in 93% yield. It was. The 1H-NMR (d-DMSO) optical spectrum of the product is as shown in FIG. 2, and the structure is as follows.

Subsequently, 49.75 g of 2-methyl-3,5-dinitrobenzoic acid was dissolved in 166.13 g of tetrahydrofuran (THF) and, in turn, 45.39 g of N , N′-Dicyclohexylcarbodiimide (DCC) was added to form a white suspended solid, then 45.39 g of tetrahydrofuran (THF) and 50.67 g of 4- (4- Phenylpiperazin-1-yl) aniline was added and waited for the white suspended solid to turn into an orange-yellow suspended solid before adding another 55.38 g of tetrahydrofuran (THF). After stirring for 12 hours, the solid was filtered to give an orange-yellow liquid product. The liquid was concentrated to 200 g at 60 ° C., poured into 1107.53 g of isopropyl alcohol solvent, and after filtration, in 74% yield, yellow solid product 2-methyl-3,5-dinitro-N— (4- (4-Phenylpiperazin-1-yl) phenyl) benzamide (2-methyl-3,5-dinitro-N- (4- (4-phenylpiperazin-1-yl) phenyl) benzamide) was obtained. The 1H-NMR (d-DMSO) optical spectrum of the product is as shown in FIG. 3, and the structure is as follows.

Finally, 92.29 g of 2-methyl-3,5-dinitro-N- (4- (4-phenylpiperazin-1-yl) phenyl) benzamide and 481.80 g of tetrahydrofuran (THF) were mixed and stirred. , 9.23 g of Pd / C was added. Using a tubing pump, 92.29 g of 70% hydrazine hydrate was slowly added dropwise. The color of the solution changed from yellow to green and after stirring for 12 hours, it finally became a white clear liquid with a black suspension of Pd / C. The impurities were filtered through diatomaceous earth, concentrated to 300 g at 60 ° C., and the filtrate was immediately poured into 1927 g of isopropyl alcohol to give a white suspended solid. After filtration, a white solid was collected and 3,5-diamino-2-methyl-N- (4- (4-phenylpiperazin-1-yl) phenyl) benzamide (3,5-diamino- A white product of 2-methyl-N- (4- (4-phenylpiperazin-1-yl) phenyl) benzamide) (monomer M1, that is, a compound represented by Formula 5) was obtained. The 1H-NMR (d-DMSO) optical spectrum of the product is as shown in FIG.

Experimental example 1

The diamine monomer M1 obtained in the synthesis example of 200 mmol was dissolved in 150 ml of N-methylpyrrolidone (NMP), and 200 mmol of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) was added to conduct a polymerization reaction. Then, N-methylpyrrolidone (NMP) was further added until the solid content became 15% by weight, and the mixture was reacted for 8 hours. Thus, a polyamic acid solution A1 having a solid content of 15% by weight was obtained.

Composition for alignment film is prepared by diluting polyamic acid solution A1 with a mixed solvent of N-methylpyrrolidone (NMP) / diethylene glycol monobutyl ether (BC) (weight ratio is 1: 1) until the solid content becomes 6.5% by weight. I got a thing. Further, the alignment film composition was coated on a glass substrate to form a thin film having a thickness of 1200 ± 100 mm, and heated to 230 ° C. and baked for 30 minutes to form an alignment film. Finally, the pair of substrates on which the alignment film is formed is taken out, and a liquid crystal (distributor: Merck, model number: MJ012008) is combined by a well-known method and sandwiched between the pair of alignment films. A liquid crystal display element D1 having a pair of electrode layers disposed on the liquid crystal layer and the pair of alignment films on the side away from the liquid crystal layer was obtained.

Comparative Examples 1-3

200 mmol of M2-M4 diamine compound (structure is as follows) dissolved in 150 ml of N-methylpyrrolidone (NMP), respectively, and 200 mmol of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) Is added to the reaction mixture, and N-methylpyrrolidone (NMP) is further added until the solid content reaches 15% by weight. After reacting for 8 hours, the polyamic acid solution A2 having a solid content of 15% by weight, A3 and A4 were obtained.

In the same manner as in Experimental Example 1, alignment films were manufactured from the polyamic acid solutions A2, A3, and A4, respectively, and liquid crystal display elements D2, D3, and D4 for forming the alignment films were manufactured.

...... M2
...... M3
...... M4

Experimental Examples 2-5

The diamine monomer M1 obtained from the synthesis example and p-phenylenediamine (para phenylene diamine, PPDA, CAS: 106-50-3) were dissolved in 200 ml of N-methylpyrrolidone (NMP) at the specific ratio shown in Table 1. Furthermore, a specific ratio of 1,2,3,4-butanetetracarboxylic dianhydride (1,2,3,4-Butanetetracarboxylic dianhydride, BT-100, CAS: 4534-73-0, distributor: Qingtai) Further, a polymerization reaction was carried out at 25 ° C. for 8 hours, followed by dehydration cyclization using toluene. After the temperature is lowered, 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) in a specific ratio (see Table 1) is added and N-methylpyrrolidone (NMP) is added to obtain a solid content. The polymer solutions A5, A6, and A7 containing a polyimide segment and a polyamic acid segment having a solid content of 15% by weight are polymerized by stirring and reacting at 25 ° C. for 8 hours. And A8 were obtained.

The polymer solutions A5, A6, A7 and A8 obtained in Experimental Examples 2 to 5 with a mixed solvent of N-methylpyrrolidone (NMP) / diethylene glycol monobutyl ether (BC) (weight ratio is 1: 1) have a solid content of 6. After diluting to 4% by weight and adding a silicone oil copolymer containing a liquid crystal group and an epoxy group with a solid content of 0.1% by weight to obtain an alignment film composition, the alignment film composition is A thin film having a thickness of 1200 ± 100 mm was formed by coating on a glass substrate and heated to 230 ° C. and baked for 30 minutes to form an alignment film. Finally, the pair of substrates on which the alignment film is formed is taken out, and a liquid crystal (distributor: Merck, model number: MJ012008) is combined by a well-known method and sandwiched between the pair of alignment films. Thus, liquid crystal display elements D5, D6, D7 and D8 having a pair of electrode layers respectively disposed on the liquid crystal layer and the pair of alignment films on the side away from the liquid crystal layer were obtained.

The above-mentioned “silicone oil copolymer containing a liquid crystal group and an epoxy group” was reacted for 6 hours in a Pt catalyst of 0.01 g of PCT-PL-50T by the following three parties, and then the temperature was raised to 120 ° C. Was obtained by evacuating for 4 hours:
(A) 25 g of 202 methyl hydrogen silicone oil (UC202);
(B) 12 g of 4 ″-(3-butenyl) -2′-fluoro-4-methyl-1,1 ′: 4 ′, 1 ″ -terphenyl (V2PGP1, sold by Corporation);
(C) 40 g of allyl glycidyl ether (AGE, CAS: 106-92-3).

A voltage of 1 V and 5 V was applied to the obtained liquid crystal display elements D1 to D8 at a temperature of 60 ° C., respectively, and the voltage holding ratios of these liquid crystal display elements were measured. The results are summarized in Table 2.

As can be seen by comparing D1 and D2 to D4, the liquid crystal display element D1 obtained from the diaminobenzene compound M1 is relatively comparative to the liquid crystal display elements D2, D3 and D4 obtained from the diamine monomers M2, M3 and M4. Since it has a high voltage holding ratio (1V-VHR> 80%; 5V-VHR> 95%), it is advantageous for solving the afterimage problem of the liquid crystal display element.

As can be seen by comparing D1, D2 to D4 and D5 to D8, even if an oriented polymer is produced using various diamine monomers, as long as the monomer M1 is mixed in these diamine monomers, the display element Voltage holding ratio (1V-VHR> 85%; 5V-VHR> 95%) and whether the oriented polymer is pure polyamic acid or a mixture of polyamic acid and polyimide. , Both can be effective.

As described above, the present invention uses a diaminobenzene compound, a polymer having an amide bond and / or an imide bond produced thereby, an alignment film composition containing the polymer, and the alignment film composition. An alignment film and a liquid crystal display device are provided. Since the diaminobenzene compound has a high polarization parameter, the liquid crystal display element has an excellent voltage holding ratio and can effectively solve the afterimage problem of the liquid crystal display element.

As described above, the present invention has been disclosed by the embodiments. However, the present invention is not intended to limit the present invention, and is within the scope of the technical idea of the present invention so that those skilled in the art can easily understand. Therefore, the scope of patent protection should be defined based on the scope of claims and the equivalent area.

Claims (9)

A diaminobenzene compound represented by the formula (1),
...... Formula (1)
In the formula, Ar is a residue of the diaminobenzene compound represented by the formula (2),
...... Formula (2)
Where
* Is the position at which the group represented by the formula (2) is bonded to two —NH ₂ of the formula (1);
Each R ₁ is independently a monovalent substituent other than a hydrogen atom or a primary amine;
X ₁ is
Or
And
R ₂ is a benzene ring or a cyclohexane ring , and the hydrogen of the benzene ring or the cyclohexane ring is independently substituted with an alkyl group having 1 to 3 carbon atoms, F, Cl, —OH, or —CN. You can,
X ₂ and X ₃ are each a linear alkylene group having 1 to 3 carbon atoms,
R ₃ is a benzene ring or a cyclohexane ring , and the hydrogen of the benzene ring or the cyclohexane ring is independently substituted with an alkyl group having 1 to 3 carbon atoms, F, Cl, —OH, or —CN. Diaminobenzene compounds that may be used. R ₂ is a group represented by the formula (3),
...... Formula (3)
The diaminobenzene compound according to claim 1, wherein Q _{1 to} Q ₄ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ₃ is a group represented by the formula (4),
...... Formula (4)
The diaminobenzene compound according to claim 1, wherein Q _{5 to} Q ₉ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. The diaminobenzene compound of Claim 1 represented by Formula (5).
...... Formula (5) Including a unit represented by any one of the formulas (6) to (9),
...... Formula (6)
...... Formula (7)
...... Formula (8)
...... Formula (9)
Where
G ₁ is an aliphatic tetracarboxylic acid residue, alicyclic tetracarboxylic acid residue or aromatic tetracarboxylic acid residue having 2 to 30 carbon atoms,
G ₂ is an aliphatic tricarboxylic acid residue, alicyclic tricarboxylic acid residue or aromatic tricarboxylic acid residue having 2 to 30 carbon atoms,
G ₃ is an aliphatic dicarboxylic acid residue, alicyclic dicarboxylic acid residue or aromatic dicarboxylic acid residue having 2 to 30 carbon atoms,
Each R ₄ is independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms;
A polymer having an amide bond, an imide bond or the two types of bonds, wherein Ar in the formula (6) to the formula (9) is a residue of the diaminobenzene compound according to any one of claims 1 to 4. . The amide bond or imide according to claim 5, wherein the proportion of the unit represented by any one of formulas (6) to (9) in the polymer is 5 mol% to 99 mol%. A polymer having a bond or the two types of bonds. An alignment film composition comprising the polymer having an amide bond, an imide bond or the two kinds of bonds according to claim 5 or 6. The alignment film manufactured with the composition for alignment films of Claim 7. A liquid crystal display element comprising the alignment film according to claim 8.