KR20120073820A - Liquid crystal alignment agent, liquid crystal alignment film manufactured using the same, and liquid crystal display device including the liquid crystal alignment film - Google Patents

Abstract

PURPOSE: A liquid crystal alignment agent, liquid crystal alignment film manufactured by using the same, and a liquid crystal display device including the liquid crystal alignment film are provided to improve voltage permeability, printability, vertical orientation, and liquid crystal orientation. CONSTITUTION: A liquid crystal alignment agent includes polymer, polyamic acids which includes recurring unit represented by chemical formula 1, polyimides which includes recurring unit represented by chemical formula 2, and a combination thereof. In the chemical formula 1 and 2, X^1 and X^2 are identical or different from each other and are respectively cycloaliphatic acid dianhydrides or tetravalent organic group which is induced from aromatic acid dianhydride. Y^1 and Y^2 are identical or different from each other and are respectively divalent organic group induced from diamines.

Description

Liquid crystal aligning agent, a liquid crystal aligning film manufactured using the same, and a liquid crystal display device comprising the liquid crystal aligning film.

The present disclosure relates to a liquid crystal aligning agent, a liquid crystal aligning film manufactured using the same, and a liquid crystal display device including the liquid crystal aligning film.

A liquid crystal display device (LCD) uses a liquid crystal alignment layer, and a polymer material is mainly used as the liquid crystal alignment layer. The liquid crystal alignment layer acts as a director in the arrangement of the liquid crystal molecules, so that the liquid crystal is moved by an electric field to form an image when the image is formed. In general, in order to obtain uniform brightness and high contrast ratio in the liquid crystal display, it is essential to orient the liquid crystal uniformly.

With the recent growth of the liquid crystal display device market, the demand for high quality liquid crystal display devices is increasing, and as the size of the liquid crystal display devices increases, the demand for high productivity liquid crystal alignment films is increasing. Accordingly, studies have been made on liquid crystal aligning agents for producing high-performance liquid crystal display alignment films having a low defect rate in a liquid crystal display device production process and capable of expressing excellent electro-optical characteristics and reliability.

In order to apply the liquid crystal alignment film materials to the liquid crystal display device substantially, optical stability and thermal stability should be excellent and there should be no afterimage.

One aspect of the present invention is to provide a liquid crystal aligning agent excellent in printability, vertical alignment and liquid crystal alignment.

Another aspect of the present invention is to provide a liquid crystal aligning film produced using the liquid crystal aligning agent.

Another aspect of the present invention is to provide a liquid crystal display device including the liquid crystal alignment layer.

In one aspect of the present invention, a liquid crystal aligning agent comprising a polymer selected from the group consisting of a polyamic acid including a repeating unit represented by the following Chemical Formula 1, a polyimide comprising a repeating unit represented by the following Chemical Formula 2, and a combination thereof To provide.

[Formula 1]

[Formula 2]

In the above Formulas 1 and 2,

X ¹ and X ² are the same or different from each other, and each independently, a tetravalent organic group derived from an alicyclic acid dianhydride or an aromatic acid dianhydride,

Y ¹ and Y ² are the same or different from each other, and each independently, a divalent organic group derived from a diamine, wherein the diamine is at least one selected from the group consisting of a diamine represented by Formula 3 and a diamine represented by Formula 4 It includes.

(3)

In Formula 3,

R ¹ to R ¹¹ are the same or different and are each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group,

L ¹ is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,

n1 is an integer of 1-10.

[Formula 4]

In Chemical Formula 4,

R ₁₂ to R ₂₂ are the same or different and are each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group,

L ² is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,

n2 is an integer of 1-10.

The diamine represented by Formula 3 may be a diamine represented by Formula 5 below.

[Chemical Formula 5]

In Formula 5,

nl is an integer from 1 to 10.

The diamine represented by Formula 4 may be a diamine represented by Formula 6 below.

[Formula 6]

In Formula 6,

n2 is an integer of 1-10.

The diamine may include a diamine represented by Chemical Formula 3 and a diamine represented by Chemical Formula 4 in a 95: 5 to 50:50 molar ratio.

The polyamic acid may have a weight average molecular weight of 10,000 to 500,000.

The polyimide is 10,000 　 It may have a weight average molecular weight of from 500,000.

When the liquid crystal aligning agent includes the polyamic acid and the polyimide, the polyamic acid and the polyimide may be included in a weight ratio of 1:99 to 50:50.

The liquid crystal aligning agent may have a solid content of 0.1 to 30% by weight.

The liquid crystal aligning agent may have a viscosity of 5 to 30 cps.

In another aspect of the present invention, there is provided a liquid crystal alignment film prepared by applying the liquid crystal alignment agent to a substrate.

In another aspect of the invention provides a liquid crystal display device comprising the liquid crystal alignment film.

The liquid crystal aligning agent can improve printability, vertical alignment property and liquid crystal alignment property.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

Unless stated otherwise in the specification, "substituted" to "substituted" means that at least one hydrogen of the functional group of the present invention is halogen (F, Br, Cl or I), hydroxy group, nitro group, cyano group, amino group (NH ₂ , NH (R ¹⁰⁰ ) or N (R ¹⁰¹ ) (R ¹⁰² ), wherein R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² are the same or different from each other, and are each independently C 1 to C 10 alkyl groups, amidino groups , Hydrazine group, hydrazone group, carboxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted haloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alicyclic organic group, substituted or unsubstituted aryl group , Substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted heteroaryl group, and substituted or unsubstituted heterocycloalkyl group means one substituted with one or more substituents selected from the group do.

Unless stated otherwise in the present specification, "alkyl group" means a C1 to C30 alkyl group, specifically, a C1 to C20 alkyl group, and "cycloalkyl group" means a C3 to C30 cycloalkyl group, and specifically C3 To C20 cycloalkyl group, "heterocycloalkyl group" means C2 to C30 heterocycloalkyl group, specifically C2 to C20 heterocycloalkyl group, "alkylene group" means C1 to C30 alkylene group , Specifically, a C1 to C20 alkylene group, "alkoxy group" means a C1 to C30 alkoxy group, specifically a C1 to C20 alkoxy group, and a "cycloalkylene group" refers to a C3 to C30 cycloalkylene group It means, specifically, C3 to C20 cycloalkylene group, "heterocycloalkylene group" means C2 to C30 heterocycloalkylene group It means, specifically, C2 to C20 heterocycloalkylene group, "aryl group" means C6 to C30 aryl group, specifically C6 to C20 aryl group, "heteroaryl group" means C2 to C30 It means a heteroaryl group, specifically means a C2 to C18 heteroaryl group, "arylene" group means a C6 to C30 arylene group, specifically means a C6 to C20 arylene group, "heteroarylene group" Means a C2 to C30 heteroarylene group, specifically means a C2 to C20 heteroarylene group, "alkylaryl group" means a C7 to C30 alkylaryl group, specifically means a C7 to C20 alkylaryl group, "Halogen" means F, Cl, Br or I.

Also, unless stated otherwise in the present specification, a heterocycloalkyl group, a heterocycloalkylene group, a heteroaryl group, and a heteroarylene group each independently represent one or more heteroatoms of N, O, S, Si, or P in one ring. It contains three, and the rest means a cycloalkyl group, a cycloalkylene group, an aryl group, and an arylene group which are carbon.

Also, unless stated otherwise, "aliphatic" means C1 to C30 alkyl, C2 to C30 alkenyl, C2 to C30 alkynyl, C1 to C30 alkylene, C2 to C30 alkenylene, or C2 to C30 alkynylene Specifically, C1 to C20 alkyl, C2 to C20 alkenyl, C2 to C20 alkynyl, C1 to C20 alkylene, C2 to C20 alkenylene, or C2 to C20 alkynylene, and "alicyclic" C3 to C30 cycloalkyl, C3 to C30 cycloalkenyl, C3 to C30 cycloalkynyl, C3 to C30 cycloalkylene, C3 to C30 cycloalkenylene, or C3 to C30 cycloalkynylene, specifically C3 to C30 cycloalkynylene C20 cycloalkyl, C3 to C20 cycloalkenyl, C3 to C20 cycloalkynyl, C3 to C20 cycloalkylene, C3 to C20 cycloalkenylene, or C3 to C20 cycloalkynylene, meaning "aromatic" 6 to C30 aryl, C2 to C30 heteroaryl, C6 to C30 arylene or C2 to C30 heteroarylene, specifically C6 to C16 aryl, C2 to C16 heteroaryl, C6 to C16 arylene or C2 to C16 Heteroarylene means.

Unless otherwise defined herein, “combination” generally means mixing or copolymerizing, in an alicyclic organic group and an aromatic organic group, at least two rings form a fused ring, or at least two rings are single Bond, O, S, C (= O), CH (OH), S (= O), S (= O) ₂ , Si (CH ₃ ) ₂ , (CH ₂ ) _p (where 1≤p≤2 ), (CF ₂ ) _q (where 1 ≦ _q ≦ 2), C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , C (CH ₃ ) (CF ₃ ) or C (═O) NH It means that they are connected to each other by. Here, "copolymerization" means block copolymer to random copolymer, and "copolymer" means block copolymer to random copolymer.

In addition, in this specification, "*" means the part connected with the same or different atom or formula.

Liquid crystal aligning agent according to an embodiment of the present invention is a polymer selected from the group consisting of polyamic acid containing a repeating unit represented by the following formula (1), polyimide comprising a repeating unit represented by the following formula (2) and combinations thereof It includes.

[Formula 1]

[Formula 2]

In the above Formulas 1 and 2,

X ¹ and X ² are the same or different from each other, and each independently, a tetravalent organic group derived from an alicyclic acid dianhydride or an aromatic acid dianhydride,

Y ¹ and Y ² are the same or different from each other, and each independently, a divalent organic group derived from a diamine, wherein the diamine is at least one selected from the group consisting of a diamine represented by Formula 3 and a diamine represented by Formula 4 It includes.

(3)

In Formula 3,

R ¹ to R ¹¹ are the same as or different from each other, and each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group, For example, it may be substituted with halogen, for example, may be substituted with fluorine.

L ¹ is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,

n1 is an integer of 1-10, Preferably, it may be 2-5. When it exists in the said range, it can have the outstanding liquid-crystal orientation. 　

[Formula 4]

In Chemical Formula 4,

R ₁₂ to R ₂₂ are the same as or different from each other, and each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group, For example, it may be substituted with halogen, for example, may be substituted with fluorine.

L ² is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,

n2 is an integer of 1-10, Preferably it may be 2-5. When it exists in the said range, it can have the outstanding liquid crystal orientation.

The liquid crystal aligning agent includes a divalent organic group derived from the diamine represented by Chemical Formula 3 and / or a divalent organic group derived from the diamine represented by Chemical Formula 4, thereby having excellent solubility, electro-optical characteristics, and liquid crystal alignment property. It can also have a good vertical alignment force.

In particular, since the liquid crystal aligning agent includes the diamine represented by Chemical Formulas 3 and / or 4, solubility and adhesiveness may be improved to maintain excellent vertical alignment force even after driving of the liquid crystal display device. Therefore, the liquid crystal aligning agent can be effectively used to prepare a vertical alignment mode (VA mode) liquid crystal alignment film.

The diamine represented by Formula 3 may be a stilbene-based photodiamine, and more specifically, may be a diamine represented by Formula 5 below, but is not limited thereto.

[Chemical Formula 5]

In Formula 5,

nl is an integer from 1 to 10.

The diamine represented by Formula 4 may be, more specifically, a diamine represented by Formula 6 below, but is not limited thereto.

[Formula 6]

In Formula 6,

n2 is an integer of 1-10.

The liquid crystal aligning agent may further include a solvent and other additives in addition to the polymer. Hereinafter, the components will be described in detail.

Polymer

The polymer is a photopolymer including a polyamic acid including a repeating unit represented by Formula 1, a polyimide including a repeating unit represented by Formula 2, or a combination thereof.

The polymers are anisotropically reacted by photoisomerization or photocrosslinking due to polarized light irradiation, thereby causing anisotropy on the surface of the polymer and inducing molecular alignment of the liquid crystal in one direction.

The polyamic acid including the repeating unit represented by Formula 1 may be synthesized from an acid dianhydride, a diamine represented by Formula 3, and a diamine represented by Formula 4. The method of preparing the polyamic acid by copolymerizing the acid dianhydride, the diamine represented by the formula (3) and the diamine represented by the formula (4) may be applied without being limited to a method known to be usable for the synthesis of polyamic acid.

In addition, the polyimide including the repeating unit represented by Formula 2 may be synthesized from an acid dianhydride, a diamine represented by Formula 3, and a diamine represented by Formula 4. Since the acid dianhydride and the diamine represented by the formula (3) and the diamine represented by the formula (4) are copolymerized and imidized to prepare a polyimide, a detailed description thereof will be omitted.

As said acid dianhydride, alicyclic acid dianhydride, aromatic acid dianhydride, or these can be used in mixture of 1 or more types.

The alicyclic acid dianhydride includes 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexene-1,2- Dicarboxylic anhydride (DOCDA), bicyclooctene-2,3,5,6-tetracarboxylic dianhydride (BODA), 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA), 1 , 2,4,5-cyclohexanetetracarboxylic dianhydride (CHDA), 1,2,4-tricarboxy-3-methylcarboxy cyclopentane dianhydride, 1,2,3,4-tetracarboxy cyclopentane dianhydride , 4,10-dioxa-tricyclo [6.3.1.0 ^2,7 ] dodecane-3,5,9,11-tetraone or a mixture of one or more thereof may be used, but is not limited thereto.

The tetravalent organic group derived from the alicyclic acid dianhydride may include at least one of the functional groups represented by the following Chemical Formulas 9 to 14, but is not limited thereto.

[Chemical Formula 9]

[Formula 10]

[Formula 11]

[Chemical Formula 12]

[Formula 13]

[Formula 14]

In Chemical Formulas 9 to 14,

R ₂₅ are the same or different and are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group,

n ₃ is an integer of 0 to 3,

R ₂₆ to R ₃₃ are the same or different and are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.

When n ₃ is an integer of 2 or more, R ₂₅ may be the same or different from each other.

The aromatic acid dianhydride may be pyromellitic dianhydride (PMDA), nonphthalic dianhydride (BPDA), oxydiphthalic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), hexafluoroisopropylidene diphthalic acid The dianhydride (6-FDA), or a mixture of one or more thereof may be used, but is not limited thereto.

The tetravalent organic group derived from the aromatic acid dianhydride may include at least one of a functional group represented by the following Formula 15 and a functional group represented by the following Formula 16, but is not limited thereto.

[Formula 15]

[Chemical Formula 16]

In Chemical Formulas 15 and 16,

R ₃₄ and R ₃₅ are the same or different and are each independently hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group,

R ₃₆ and R ₃₇ are the same or different and are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group,

n ₄ and n ₅ are each independently an integer of 0 to 3,

A ₁ is a single bond, O, CO, substituted or unsubstituted C1 to C6 alkylene group (eg C (CF ₃ ) ₂ ), substituted or unsubstituted C3 to C30 cycloalkylene group, or substituted or unsubstituted C2 to C30 heterocycloalkylene group.

When n ₄ is an integer of 2 or more, R ₃₆ may be the same or different from each other. Similarly, when n ₅ is an integer of 2 or more, R ₃₇ may be the same or different from each other.

When the diamine includes both the diamine represented by the formula (3) and the diamine represented by the formula (4), it may include the diamine represented by the formula (3) and the diamine represented by the formula (3) in a 95: 5 to 50:50 molar ratio.

When the polymer comprises a divalent organic group derived from the diamine represented by the formula (3) and a divalent organic group derived from the diamine represented by the formula (4) within the above range, the solubility and adhesiveness is effectively improved to improve the vertical alignment force In particular, the vertical alignment force can be excellently maintained even after driving the liquid crystal display, and the liquid crystal alignment and the electro-optical characteristics can be effectively improved.

The polyamic acid may have a weight average molecular weight of 10,000 to 500,000. In addition, the polyimide may have a weight average molecular weight of 10,000 to 500,000. When the weight average molecular weight of the polyamic acid and the polyimide is within the above range, solubility, thermal stability and chemical resistance can be effectively improved, and an appropriate viscosity can be maintained to have excellent printability and to form a uniform film easily. .

When the liquid crystal aligning agent includes both the polyamic acid and the polyimide, the polyamic acid and the polyimide may be included in a weight ratio of 1:99 to 50:50. When the polyamic acid and the polyimide are included in the above range, the orientation stability can be improved. Specifically, the polyamic acid and the polyimide may be included in a weight ratio of 10:90 to 50:50.

In the liquid crystal aligning agent, the polymer may be included in an amount of 1 wt% to 25 wt%. When the polymer is included in the above range can improve the printability and liquid crystal alignment. Specifically, the polymer may be included in 3 wt% to 20 wt%.

menstruum

The liquid crystal aligning agent includes a solvent suitable for dissolving the polymer. As a result, the liquid crystal aligning agent may have excellent spreadability and adhesiveness with the substrate.

Examples of suitable solvents for dissolving the polymer include N-methyl-2-pyrrolidone; N, N-dimethyl acetamide; N, N-dimethyl formamide; Dimethyl sulfoxide; ? -butyrolactone; Tetrahydrofuran (THF); And phenolic solvents such as meta cresol, phenol, and halogenated phenol, but are not limited thereto.

The solvent may further include 2-butyl cellosolve (2-BC), thereby improving printability. In this case, the 2-butyl cellosolve may be included in an amount of 1 to 70% by weight, specifically, 20 to 60% by weight, based on the total amount of the solvent including 2-butyl cellosolve. When 2-butyl cellosolve is included in the above range, the printability can be easily improved. 　

In addition, the solvent may further include a poor solvent alcohols, ketones, esters, ethers, hydrocarbons, or halogenated hydrocarbons in an appropriate ratio within the limit of the precipitation of the soluble polyimide polymer. The poor solvents may lower the surface energy of the liquid crystal aligning agent to improve spreadability and flatness during coating.

The poor solvent may be included in an amount of 1 kPa to 90% by weight, specifically 1 to 70% by weight, based on the total amount of the solvent including the poor solvent.

Specific examples of the poor solvent include methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl Acetate, diethyl oxalate, malonic ester, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol phenyl ether, ethylene glycol phenylmethyl ether, ethylene glycol phenylethyl ether, di Ethylene glycol dimethyl ether, diethylene glycol ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol methyl ether acetate, ethylene glycol ethyl on Le acetate, 4-hydroxy-4-methyl-2-pentanone, 2-hydroxy ethyl propionate, 2-hydroxy-2-methyl ethyl propionate, ethoxy acetate ethyl, hydroxy ethyl acetate, 2-hydroxy- Methyl 3-methyl butyrate, methyl 3-methoxy propionate, ethyl 3-methoxy propionate, ethyl 3-ethoxy propionate, methyl 3-ethoxy propionate, methyl methoxy butanol, ethyl methoxy butanol, methyl ethoxy butanol, Ethyl ethoxy butanol, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichloro butane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, Or these can be used in mixture of 1 or more types.

The content of the solvent in the liquid crystal aligning agent is not particularly limited, but may be used so that the content of solids in the liquid crystal aligning agent is 0.1 to 30% by weight, specifically, the content of solids is 1 to 10% by weight. Can be used. When the content of solids is within the above range, the uniformity of the film can be properly maintained and the appropriate viscosity can be maintained by being less affected by the contamination of the substrate surface at the time of printing, thereby preventing the uniformity of the film due to the high viscosity at the time of printing. Can exhibit an appropriate transmittance.

The liquid crystal aligning agent may have a viscosity of 5 to 30 cps, specifically, may have a viscosity of 10 to 20 cps. 　 When the viscosity of a liquid crystal aligning agent exists in the said range, coating film uniformity and applicability | paintability can be improved.

Other additives

Liquid crystal aligning agent according to an embodiment of the present invention may further include other additives.

The other additives include epoxy compounds. The epoxy compound is used for improving the reliability and the electro-optical property, and the epoxy compound may use at least one epoxy compound containing 2 to 8 epoxy groups, specifically 2 to 4 epoxy groups.

The epoxy compound may be included in 0.1 to 50 parts by weight, specifically 1 to 30 parts by weight based on 100 parts by weight of the polymer. When the epoxy compound is included in the above range, it is possible to easily improve the reliability and electro-optical properties, while exhibiting proper printability and flatness when applied to the substrate.

Examples of the epoxy compound may include a compound represented by the following Formula 17, but is not limited thereto.

[Formula 17]

In Chemical Formula 17,

A ₁₂ is a substituted or unsubstituted C6 to C12 aromatic organic group, or a substituted or unsubstituted divalent C6 to C12 alicyclic organic group, or a substituted or unsubstituted divalent C6 to C12 aliphatic organic group such as substituted or unsubstituted It is a ring C1-C6 alkylene group.

Specific examples of the epoxy compound include N, N, N ', N'-tetraglycidyl-4,4'-diaminophenylmethane (TGDDM), N, N, N', N'-tetraglycidyl- 4,4'-diaminophenylethane, N, N, N ', N'-tetraglycidyl-4,4'-diaminophenylpropane, N, N, N', N'-tetraglycidyl- 4,4'-diaminophenylbutane, N, N, N ', N'-tetraglycidyl-4,4'-diaminobenzene, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin digly Cydyl ether, 2,2-dibromoneopentylglycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ', N'- Tetraglycidyl-1,4-phenylenediamine, N, N, N ', N'-tetraglycidyl-m-xylenediamine, N, N, N', N'-tetraglycidyl-2 , 2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis [4- (N, N-diglycidyl-4-aminophenoxy) phenyl] propane, N, N, N ' , N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 1,3-bis (N, N- diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N- Diglycidylaminomethyl) benzene and the like, but are not limited thereto.

Moreover, in order to improve printability, a suitable surfactant or coupling agent may be further used as an additive.

The liquid crystal alignment layer may be manufactured using the liquid crystal alignment agent.

Although the liquid crystal aligning film can apply | coat the liquid crystal aligning agent melt | dissolved in the said organic solvent to a board | substrate, and form it, As a method of apply | coating the said liquid crystal aligning agent to the said board | substrate, a spin coat method, a flexographic printing method, the inkjet method, etc. are mentioned. Can be. Among them, the flexographic printing method is excellent in uniformity of the formed coating film and can be easily enlarged, and therefore, it can be generally used.

The substrate can be used without particular limitation as long as it is a substrate having high transparency, and a plastic substrate such as a glass substrate or an acrylic substrate or a polycarbonate substrate can be used. In addition, using a substrate on which an indium-tin oxide (ITO) electrode or the like for driving a liquid crystal is used, the manufacturing process may be simplified.

The liquid crystal aligning agent is uniformly coated on a substrate in order to increase the uniformity of the coating film, and then at a temperature of room temperature to 200 ° C, specifically at a temperature of 30 ° C to 150 ° C, and more specifically of 40 ° C to 120 ° C. Temporary drying can be carried out for 1 to 100 minutes at a temperature. By adjusting the volatilization degree of each component of the liquid crystal aligning agent through the temporary drying, a uniform and uneven coating film can be obtained.

Thereafter, the liquid crystal aligning film can be formed by evaporating the solvent by firing at a temperature of 80 ° C to 300 ° C, specifically, 120 ° C to 280 ° C for 5 minutes to 300 minutes.

The liquid crystal alignment film formed by the above method may be used in a liquid crystal display device without uniaxial alignment treatment by polarized ultraviolet irradiation or in some applications such as a vertical alignment layer.

Specifically, the liquid crystal alignment layer according to the exemplary embodiment of the present invention may be subjected to uniaxial alignment treatment by exposing for 0.1 to 180 minutes at an energy of 10 mJ to 5,000 mJ.

According to still another embodiment of the present invention, a liquid crystal display device including the liquid crystal alignment layer is provided.

Liquid crystal display devices (LCDs) use liquid crystals that are twisted at 90 degrees between polarizers and analyzers whose polarization directions are perpendicular to each other. In the absence of voltage, linearly polarized light passing through the polarizer is rotated along the direction of the locally different liquid crystal aligner and deflected by 90 degrees. As a result, the light rotates while passing through the liquid crystal layer and passes through the analyzer. When voltage is applied, the liquid crystals are lined up in a direction parallel to the electric field direction so that the linearly flattened light passes through the liquid crystal layer without rotation, so that the liquid crystals collide perpendicularly to the polarization direction of the analyzer and cannot pass. Since the control of the liquid crystal can produce a selective transmission of light, in general, in order to obtain uniform brightness and high contrast ratio in the LCD, uniform alignment of the liquid crystal over the LCD panel is very important. The liquid crystal alignment layer can be usefully applied in this respect.

In addition, the liquid crystal display device, for example, by applying a liquid crystal alignment agent to a glass substrate on which a transparent indium tin oxide (ITO) conductive film is deposited, and curing it with heat to form an alignment layer, and then bonded the two substrates in opposite directions It can manufacture by the method of inject | pouring a liquid crystal, a liquid crystal dropping method which drips a liquid crystal to one board | substrate, or attaches and opposes a counter substrate.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the following Examples and Comparative Examples are for illustrative purposes only and are not intended to limit the present invention.

Example

( Example One: Polyamic acid (SAA-1)  Preparation of liquid crystal aligning agent to include)

A four-necked flask equipped with a stirrer, a thermostat, a nitrogen gas injector, and a cooler under dark conditions, while passing nitrogen under 2,4-diaminophenethyl 4- (4- (2,2) 0.9 moles of, 2-trifluorobutoxy) -styryl) benzoate and 4- (2,4-diaminostyryl) phenyl 4- (4,4,4-trifluoro moiety represented by the following formula (19): 0.1 mol of oxy) benzoate was added thereto, and N-methyl-2-pyrrolidone (NMP) was added thereto to prepare a mixed solution.

[Chemical Formula 18]

[Formula 19]

1.0 mol of 4,10-dioxa-tricyclo [6.3.1.0 ^2,7 ] dodecane-3,5,9,11-tetraone was added to the mixed solution and stirred vigorously for 1 hour. The reaction was performed for 24 hours while maintaining the temperature at 30 ° C. to 60 ° C. to prepare a polyamic acid (PAA-1) solution. The polyamic acid (PAA-1) solution was distilled to prepare a polyamic acid (PAA-1). Got. The weight average molecular weight of the said polyamic acid (PAA-1) was 200,000.

To the polyamic acid (PAA-1), a mixed solvent of VN-methyl-2-pyrrolidone (NMP), Gγ-butyrolactone and 2-butyl cellosolve (volume ratio = 3: 4: 3) is added, and room temperature After stirring for 24 hours to prepare a liquid crystal aligning agent comprising a polyamic acid (SAA-1).

( Example 2 to 8: Polyamic acid ( SAA -2) to Polyamic acid (SAA-8)  Preparation of liquid crystal aligning agent to include)

As shown in Table 1 below, using a compound represented by the formula (18) and a compound represented by the formula (19) as a diamine, in the same manner as in Example 1 polyamic acid (SAA-2) to polyamic acid (SAA-8) A liquid crystal aligning agent containing was prepared.

( Example 9: Polyimide (SI-1)  Preparation of liquid crystal aligning agent to include)

In a four-necked flask equipped with a stirrer, a temperature controller, a nitrogen gas injector, and a cooler, under nitrogen conditions, 2,4-diaminophenethyl 4- (4- (2,2) 0.9 moles of, 2-trifluorobutoxy) -styryl) benzoate and 4- (2,4-diaminostyryl) phenyl 4- (4,4,4-trifluoro moiety represented by the following formula (19): 0.1 mol of oxy) benzoate was added thereto, and N-methyl-2-pyrrolidone (NMP) was added thereto to prepare a mixed solution.

1.0 mol of 4,10-dioxa-tricyclo [6.3.1.0 ^2,7 ] dodecane-3,5,9,11-tetraone was added to the mixed solution and stirred vigorously for 1 hour. The reaction was carried out for 24 hours while maintaining the temperature at 30 ℃ to 60 ℃ to prepare a polyamic acid solution.

몰 3.0 mol of acetic anhydride and 5.0 mol of pyridine were added to the polyamic acid solution prepared above, followed by a cyclization reaction at 80 ° C. for 4 hours, and the catalyst and solvent were removed by vacuum distillation to obtain polyimide (PI-11). ) The weight average molecular weight of the said polyimide ((PI-11) was 210,000.

To the polyimide (PI-11) prepared above, a mixed solvent of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone and 2-butyl cellosolve was added (volume ratio = 3: 4: 3) And stirring at room temperature for 24 hours to prepare a liquid crystal aligning agent containing polyimide (SI-1).

( Example 10 to 16: polyimide ( SI -2) to Polyimide (SI-8)  Preparation of liquid crystal aligning agent to include)

As shown in Table 1 below, using a compound represented by the formula (18) and a compound represented by the formula (19) as a diamine in the same manner as in Example 9 polyimide (SI-2) to polyimide (SI-8) A liquid crystal aligning agent containing was prepared.

( Comparative example 1 to 2: Polyamic acid ( CAA -1) to Polyamic acid (CAA-2)  Preparation of liquid crystal aligning agent to include)

As shown in Table 2 below, using a compound represented by the formula (20) and a compound represented by the formula (21) as diamine, in the same manner as in Example 1 polyamic acid (CAA-1) to polyamic acid (CAA-2) A liquid crystal aligning agent containing was prepared.

[Chemical Formula 20]

[Formula 21]

( Comparative example  3 to 4: polyimide ( CI -1) to Polyimide (CI-2)  Preparation of liquid crystal aligning agent to include)

As shown in Table 2 below, using a compound represented by the formula (20) and a compound represented by the formula (21) as diamine, in the same manner as in Example 9 polyimide (CI-1) to polyimide (CI-2) A liquid crystal aligning agent containing was prepared.

Polymer type Usage amount of formula (18)
(mole) Usage amount of formula 19
(mole) In liquid crystal aligning agent
Solid content
(weight%) Molecular Weight
(Mw) Example 1 SAA-1 0.90 0.10 7.5 200,000 Example 2 SAA-2 0.95 0.05 7.5 210,000 Example 3 SAA-3 0.85 0.15 7.5 200,000 Example 4 SAA-4 0.80 0.20 7.5 200,000 Example 5 SAA-5 0.75 0.25 7.5 210,000 Example 6 SAA-6 0.70 0.30 7.5 210,000 Example 7 SAA-7 0.65 0.35 7.5 200,000 Example 8 SAA-8 0.60 0.40 7.5 210,000 Example 9 SI-1 0.90 0.10 7.5 210,000 Example 10 SI-2 0.95 0.05 7.5 220,000 Example 11 SI-3 0.85 0.15 7.5 190,000 Example 12 SI-4 0.80 0.20 7.5 200,000 Example 13 SI-5 0.75 0.25 7.5 190,000 Example 14 SI-6 0.70 0.30 7.5 190,000 Example 15 SI-7 0.65 0.35 7.5 190,000 Example 16 SI-8 0.60 0.40 7.5 220,000

Polymer type Usage amount of formula 20
(mole) Usage amount of formula 21
(mole) In liquid crystal aligning agent
Solid content
(weight%) Molecular Weight
(Mw) Comparative Example 1 CAA-1 0.90 0.10 7.5 210,000 Comparative Example 2 CAA-2 0.70 0.30 7.5 210,000 Comparative Example 3 CI-1 0.90 0.10 7.5 220,000 Comparative Example 4 CI-2 0.70 0.30 7.5 200,000

<Property evaluation>

LCD Orientation  And Pretilt  evaluation

In order to evaluate the liquid-crystal orientation of the liquid crystal aligning agent, the liquid crystal cell was produced and used. The manufacture of the liquid crystal cell is as follows.

Patterned using a photolithography process to remove the other portion of ITO, leaving only a 1.5 cm × 1.5 cm square ITO shape and an electrode ITO shape for voltage application on a standard sized ITO glass substrate.

The liquid crystal aligning agent prepared in Examples 1 to 16 was applied to the patterned ITO substrate, spin-coated to a thickness of 0.1 μm, and then subjected to curing at 70 ° C. and 210 ° C.

The two I substrates subjected to the curing process using an exposure machine (UIS-S2021J7-YD01, Ushio LPUV) were exposed under a certain angle and a constant energy so that the two substrates were exposed in opposite directions (for VA mode, 90 degrees). Thereafter, square ITO shapes were joined up and down consistently while maintaining a cell gap of 4.75 mu m. In the exposure, a light source used a 2 kW deep UV ramp (UXM-2000).

After filling the liquid crystal in the cell prepared in this way, the liquid crystal alignment was observed using an orthogonally polarized optical microscope, and the pretilt angle was measured using a crystal rotation method, and the results are shown in Table 3 below. Shown in At this time, evaluation criteria of liquid crystal alignment are as follows.

<Liquid crystal orientation evaluation criteria>

Good: no occurrence of disclination

Poor: Discretion occurred

Evaluation of Electrical Properties of Liquid Crystal Alignment Film

The electrical characteristics of the liquid crystal alignment layer were measured by using a liquid crystal cell with a cell gap of 4.75 μm, measuring a voltage holding ratio (VHR) at room temperature and 60 ° C., and measuring residual DC voltage. Evaluated. The results are shown in Table 3 below.

<Voltage Transmittance Evaluation Criteria>

Good: 99.0% or more

Poor: less than 99.9%

The voltage retention ratio refers to the extent to which the liquid crystal layer in the state of floating with the external power source maintains the charged voltage during the non-selection period in the active driving type TFT-LCD, and a value close to 100% is ideal.

The residual DC voltage refers to a voltage applied to the liquid crystal layer even when no impurities are applied to the alignment layer, and thus no impurities are applied to the alignment layer. As a method of measuring the residual DC voltage, a method using flicker and a method using a capacitance change curve (C-V) of the liquid crystal layer according to DC voltage are common.

The evaluation results of the electrical characteristics of the liquid crystal alignment layer using the liquid crystal cell are shown in Table 3 below.

Liquid crystal aligning agent Liquid crystal alignment Voltage transmittance Voltage retention rate
(%) Residual DC voltage
(by CV)
(mV) Pretilt
(°) Wire diameter blind spot after 168 hours of driving
(°) Room temperature
(25 ℃) High temperature
(60 ℃) Example 1 Good Good 99.31 99.30 48 88.01 88.02 Example 2 Good Good 99.10 99.08 61 88.05 88.02 Example 3 Good Good 99.50 99.36 45 88.05 88.05 Example 4 Good Good 99.48 99.38 47 88.12 88.06 Example 5 Good Good 99.35 99.36 47 88.27 88.15 Example 6 Good Good 99.36 99.15 51 88.28 88.17 Example 7 Good Good 99.35 99.12 50 88.43 88.32 Example 8 Good Good 99.41 99.10 48 88.42 88.33 Example 9 Good Good 99.47 99.16 46 88.56 88.52 Example 10 Good Good 99.12 99.15 60 88.54 88.45 Example 11 Good Great 99.63 99.32 51 88.25 88.18 Example 12 Good Good 99.51 99.28 48 88.22 88.19 Example 13 Good Good 99.52 99.26 50 88.21 88.25 Example 14 Good Good 99.48 99.18 48 88.15 88.25 Example 15 Good Good 99.51 99.17 51 88.09 87.98 Example 16 Good Good 99.56 99.15 45 88.20 88.15 Comparative Example 1 Bad Good 99.10 99.05 56 88.56 88.16 Comparative Example 2 Bad Good 99.23 99.01 60 88.75 88.26 Comparative Example 3 Bad Bad 98.89 98.45 45 88.63 88.20 Comparative Example 4 Bad Bad 98.99 98.75 70 88.67 88.33

As shown in Table 3, the liquid crystal navigator prepared in Examples 1 to 16 can be confirmed that the meeting does not occur, the liquid crystal alignment properties are excellent and the voltage transmittance is 99.0% or more.

Voltage retention is at least 99.0% at room temperature and high temperature, the residual DC voltage is 61 mV or less, it can be seen that the liquid crystal navigator prepared in Examples 1 to 16 is excellent.

It can be seen that the pretilt angle is excellent in the liquid crystal aligning agent prepared in Examples 1 to 16 around 88 °, and when looking at the amount of change of the pretilt angle after driving for 168 hours, the liquid crystal aligning agent prepared in Examples 1 to 16 is 0. It can be seen that there is no change or a small change from ° to 0.12 ° to maintain excellent vertical alignment force even after driving. This is because the structures of the polyamic acid and the polyimide according to the above embodiment react in a constant direction by light irradiation, and thus the ability to orient the liquid crystal is very excellent.

On the other hand, in the case of the liquid crystal alignment agents prepared in Comparative Examples 1 and 4, the liquid crystal alignment is poor, and since the amount of change in the pretilt angle after 168 hours of driving is significantly larger than 0.3 °, the ability to maintain the vertical alignment force after driving is poor. Can be confirmed.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Claims (10)

A liquid crystal aligning agent comprising a polymer selected from the group consisting of a polyamic acid comprising a repeating unit represented by the following formula (1), a polyimide comprising a repeating unit represented by the following formula (2), and a combination thereof:
[Formula 1]

(2)

In Chemical Formulas 1 and 2,
X ¹ and X ² are the same or different from each other, and each independently, a tetravalent organic group derived from an alicyclic acid dianhydride or an aromatic acid dianhydride,
Y ¹ and Y ² are the same or different from each other, and each independently, a divalent organic group derived from a diamine, wherein the diamine is at least one selected from the group consisting of a diamine represented by Formula 3 and a diamine represented by Formula 4 Including,
(3)

In Chemical Formula 3,
R ¹ to R ¹¹ are the same or different and are each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group,
L ¹ is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,
n1 is an integer of 1 to 10,
[Chemical Formula 4]

In Chemical Formula 4,
R ₁₂ to R ₂₂ are the same or different and are each independently a substituted or unsubstituted aliphatic organic group, a substituted or unsubstituted alicyclic organic group, or a substituted or unsubstituted aromatic organic group,
L ² is a substituted or unsubstituted C1-C30 alkylene group, and at least one -CH ₂ -group of the alkylene group is independently -O-, -OOC-, -COO-, -OCOO-, -NHCO-,- May be substituted with CONH- or -CO-,
n2 is an integer of 1-10. The method of claim 1,
The diamine represented by the formula (3) is a liquid crystal aligning agent is a diamine represented by the formula (5):
[Chemical Formula 5]

In Formula 5,
nl is an integer from 1 to 10. The method of claim 1,
The diamine represented by the formula (4) is a liquid crystal aligning agent is a diamine represented by the following formula (6):
[Formula 6]

In Formula 6,
n2 is an integer of 1-10. The method of claim 1,
The diamine is a liquid crystal aligning agent comprising a diamine represented by the formula (3) and a diamine represented by the formula (4) of 95: 5 to 50:50 molar ratio. The method of claim 1,
Wherein said polyamic acid and said polyimide have a weight average molecular weight of 10,000 to 500,000. The method of claim 1,
When the liquid crystal aligning agent includes the polyamic acid and the polyimide, the liquid crystal aligning agent containing the polyamic acid and the polyimide in a weight ratio of 1:99 to 50:50. The method of claim 1,
The liquid crystal aligning agent having a solid content of 0.1 to 30% by weight. The method of claim 1,
The liquid crystal aligning agent having a viscosity of 5 to 30 cps. A liquid crystal alignment film prepared by applying the liquid crystal alignment agent according to any one of claims 1 to 8 to a substrate. A liquid crystal display device comprising the liquid crystal alignment film according to claim 9.