KR20100077671A - Alignment agent of liquid crystal, alignment film of liquid crystal including the same, and liquid crystal display including same - Google Patents

Abstract

PURPOSE: An alignment agent of a liquid crystal is provided to obtain high vertical alignment power and simplicity of dropping liquid crystal and to obtain excellent adhesive force with a panel, chemical resistance, and electro-optical properties. CONSTITUTION: An alignment agent of a liquid crystal includes a polymer which is selected from a group comprising polyamide acid marked as a chemical formula 1, a polyamide polymer marked as a chemical formula 2, and a their combination. In the chemical formula 1 and 2, R1 and R3 are a tetravalent organic group which is induced from dianhydrides selected from aliphatic cyclic acid dianhydride and aromatic acid dianhydride.

Description

ALIGNMENT AGENT OF LIQUID CRYSTAL, ALIGNMENT FILM OF LIQUID CRYSTAL INCLUDING THE SAME, AND LIQUID CRYSTAL DISPLAY INCLUDING SAME}

The present invention relates to a liquid crystal aligning agent for use in a liquid crystal display device, a liquid crystal alignment film comprising the same, and a liquid crystal display device including the same, and more particularly, high vertical alignment force, easy liquid crystal dropping, excellent panel substrate adhesion, A liquid crystal aligning agent having a chemical property, a stable liquid crystal alignment regulating force, excellent electro-optical properties, a low level of afterimage, a high level of reliability, a liquid crystal alignment layer including the same, and a liquid crystal display device including the same.

A liquid crystal display (LCD) uses a liquid crystal alignment film. As the liquid crystal alignment film, a polymer material is mainly used.

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, it is essential to orient the liquid crystal uniformly in the liquid crystal display.

Conventionally, a rubbing method is used in which a polymer film such as polyimide is applied to a substrate such as glass, and the surface is rubbed in a predetermined direction with fibers such as nylon or polyester as a conventional method for orienting liquid crystals.

Polyimide resins for liquid crystal aligning agents generally used include, as aromatic acid dianhydrides, pyromellitic dianhydrides, non-phthalic dianhydrides, and the like, and aromatic diamines include paraphenylenediamine, metaphenylenediamine, and 4,4-methylenedi. Aniline, 2,2-bisamino phenylhexafluoropropane, metabisaminophenoxydiphenylsulfone, parabisaminophenoxydiphenylsulfone, 4,4-bisaminophenoxyphenylpropane, 4,4-bisaminophenoxyphenyl It is produced by polycondensation of these using hexafluoropropane or the like.

However, when only aromatic acid dianhydride and aromatic diamine are used as described above, thermal stability, chemical resistance, mechanical properties, etc. are excellent, but transparency and solubility are degraded by charge transfer complex, and electro-optical properties are deteriorated. There is this.

In order to solve the above problems, there is an attempt to improve the problem by introducing an aliphatic cyclic acid dianhydride monomer or aliphatic diamine (Japanese Patent Laid-Open No. 11-84391), having a side chain for increasing the pretilt angle of the liquid crystal and improving stability A functional diamine or a functional acid dianhydride having a side chain is introduced (Japanese Patent Laid-Open No. 06-136122).

In addition, the development of a vertically aligned alignment film that can be applied in a vertical alignment mode (VA mode) in which liquid crystals are oriented vertically from the surface to induce liquid crystal driving (US Pat. No. 5,420,233). Since the vertical alignment mode has a large viewing angle and does not require an alignment process such as a rubbing process, it is easy to enlarge the size, and many panel manufacturers apply it to large display devices of 40 inches or more.

Meanwhile, with the recent growth of the liquid crystal device (LCD) market, the demand for high-quality display devices is continuously increasing, and the demand for high-performance alignment films is increasing in large liquid crystal display device manufacturers. Is growing.

Therefore, there is a continuous demand for a high-performance liquid crystal alignment film sufficient to satisfy different requirements of the liquid crystal display device such as low defect rate, excellent electro-optical characteristics, and high reliability in the LCD production process. The liquid crystal aligning agent of usually consists of one diamine compound in most cases. In order to implement a vertical or torsional orientation in such a diamine compound, a functional diamine compound having a side chain group is introduced. In the case of a torsion alignment layer, the side chain induces a liquid crystal on the surface of the alignment layer to have a constant pretilt angle so as to have a uniform alignment. In the case of the vertical alignment layer, a large amount of hydrophobic side chains lower the surface tension of the alignment layer, and are positioned in a direction perpendicular to the main chain to express a high pretilt angle of 85 degrees or more.

However, the alkyl group having 6 to 24 carbon atoms used as the side chain of the functional diamine has a problem in that the pretilt angle is deformed when the physical impact such as liquid crystal dropping occurs due to the flexibility. In addition, in the case of the vertical alignment layer using the side chain group as described above, the surface tension is lowered due to the side chain to make the hydrophobicity of the surface high, when the liquid crystal dropping, the spreading of the liquid crystal is not secured may cause problems in the liquid crystal filling (filling) of the panel .

In addition, the recent LCD panel technology is constantly progressing in order to secure a high pixel number in the LCD panel having a small visible area according to the development of portable display products.

To achieve high pixel counts on small visible areas, the effective visible area within the panels must be increased. In order to increase the effective visible area, in general, the sealant is applied to a portion other than the effective visible area to which the alignment film is applied to maintain the adhesion of the upper and lower substrates. to be.

At this time, there is a problem that the adhesiveness of the sealant applied on the alignment film is significantly lower than the sealant applied to the portion without the alignment film.

One embodiment of the present invention provides a liquid crystal aligning agent having excellent vertical alignment force, chemical resistance, stable liquid crystal alignment force, liquid crystal dropping ease, excellent substrate adhesion, electro-optic properties, reliability of afterimages, and excellent processability will be.

Another embodiment of the present invention to provide a liquid crystal alignment film comprising the liquid crystal aligning agent.

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

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by the average person from the following description.

According to one embodiment of the present invention, a liquid crystal aligning agent including a polymer selected from the group consisting of a polyamic acid represented by the following Chemical Formula 1, a polyimide polymer represented by the following Chemical Formula 2, and a combination thereof is provided.

[Formula 1]

[Formula 2]

(In Chemical Formulas 1 to 2,

R ₁ and R ₃ are each independently a tetravalent organic group derived from an acid dianhydride selected from the group consisting of aliphatic cyclic acid dianhydrides, aromatic acid dianhydrides, and combinations thereof;

R ₂ and R ₄ are each independently a first functional diamine represented by the following formula (3), a second functional diamine represented by the following formula (4), and a divalent organic group derived from an aromatic diamine.)

(3)

(In Chemical Formula 3,

R ₅ is a hydrogen atom; A substituted or unsubstituted alkyl group having 1 to 31 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

R ₆ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₆ is an integer of 0 to 3.)

[Formula 4]

In Chemical Formula 4,

R ₇ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₈ , R ₉ and R ₁₀ are, independently from each other, -H, -CH ₃ or a halogen atom,

R ₁₁ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₁₂ is a linear, branched or cyclic substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.

According to another embodiment of the present invention to provide a liquid crystal alignment film prepared by applying the liquid crystal aligning agent to a substrate.

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

Other specific details of embodiments of the present invention are included in the following detailed description.

The liquid crystal aligning agent of the present invention has high vertical alignment force, chemical resistance, stable liquid crystal alignment force, liquid crystal dropping ease, excellent substrate adhesiveness, electro-optic properties, and excellent afterimage reliability, and excellent processability and thus used in the cleaning process. The liquid crystal orientation is not affected by the cleaning solvent, the orientation force is not deformed even during the physical impact of the dropped liquid crystal during the liquid crystal dropping process and the application of voltage for a long time, and is caused by printing defects during the LCD panel manufacturing process. It is easy to remove the alignment layer during the substrate rework process.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

Unless stated otherwise in the present specification, "alkyl group" means an alkyl group having 1 to 20 carbon atoms, "alkylene group" means an alkylene group having 1 to 6 carbon atoms, and "cycloalkylene group" means a cyclo having 3 to 30 carbon atoms. An alkylene group, "heterocycloalkylene group" means a heterocycloalkylene group of C2-C30, "aryl group" means an aryl group of C6-C30, "heteroaryl group" means a C2-C30 It means a heteroaryl group of, "arylene" group means an arylene group of C2-C20 carbon atoms, "halogen atom" or "halogen group" means F, Cl, Br, or I.

Unless otherwise specified in the present invention, an "alicyclic ring group" means a cycloalkyl group having 3 to 50 carbon atoms, or a cycloalkenyl group having 3 to 50 carbon atoms, and a "heterocyclic group" means C3 to C3 including a hetero atom. It means a C50 heteroaryl group, a heterocycloalkyl group having 1 to 50 carbon atoms, a heterocycloalkenyl group having 1 to 50 carbon atoms, a heterocycloalkynyl group having 1 to 50 carbon atoms or a fused ring thereof. In addition, the heterocyclic group may include 1 to 20, more specifically 1 to 15 hetero atoms.

As used herein, unless otherwise defined, at least one hydrogen atom is a halogen group, an alkyl group having 1 to 30 carbon atoms, a haloalkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or a hetero atom having 2 to 30 carbon atoms. It means what is substituted by the aryl group and the alkoxy group of 1 to 20 carbon atoms.

In addition, in this specification, unless otherwise defined, hetero means one to three carbon atoms substituted with a hetero atom which is N, O, S, or P.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

According to one embodiment of the present invention, a liquid crystal aligning agent comprising a polyamic acid or a soluble polyimide containing two types of side chains having different structures, the liquid crystal aligning agent has excellent vertical alignment force, It is easy and is excellent in adhesiveness of a board upper / lower board | substrate.

Liquid crystal aligning agent according to an embodiment of the present invention includes a polymer selected from the group consisting of a polyamic acid represented by the formula (1), a polyimide polymer represented by the formula (2), and combinations thereof. In the case where the polyamic acid and the polyimide polymer are mixed and used, these mixing ratios can be appropriately adjusted, and there is no need to specifically limit them.

[Formula 1]

[Formula 2]

(In Chemical Formulas 1 to 2,

R ₁ and R ₃ are each independently a tetravalent organic group derived from an acid dianhydride selected from the group consisting of aliphatic cyclic acid dianhydrides, aromatic acid dianhydrides, and combinations thereof;

R ₂ and R ₄ are each independently a first functional diamine represented by the following formula (3), a second functional diamine represented by the following formula (4), and a divalent organic group derived from an aromatic diamine.

(3)

In Chemical Formula 3,

R ₅ is a hydrogen atom; A substituted or unsubstituted alkyl group having 1 to 31 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

R ₆ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₆ is an integer of 0 to 3.

[Formula 4]

In Chemical Formula 4,

R ₇ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₈ , R ₉ and R ₁₀ are, independently from each other, -H, -CH ₃ or a halogen atom,

R ₁₁ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₁₂ is a linear, branched or cyclic substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.)

Hereinafter, each component will be described in detail.

(1) polyamic acid

The polyamic acid represented by Chemical Formula 1 may be synthesized from an acid dianhydride and a diamine. The method of preparing the polyamic acid by copolymerizing the acid dianhydride and the diamine may be applied without being limited to a method known to be possible to copolymerize the conventional polyamic acid. As said acid dianhydride, aliphatic cyclic acid dianhydride, aromatic acid dianhydride, or these can be used in mixture of 1 or more types.

The diamine includes a first functional diamine represented by Chemical Formula 3 and a second functional diamine represented by Chemical Formula 4, and includes an aromatic diamine.

Thus, in the polyamic acid to be produced, some will contain a divalent organic group derived from the first functional diamine, others will have a divalent organic group derived from the second functional diamine, and the rest will contain a divalent organic group derived from the aromatic diamine. Done.

The diamine may include 1 to 30 mol% of the first functional diamine, 1 to 40 mol% of the second functional diamine, and may include the remainder of the aromatic diamine.

Functional diamines represented by Formula 1 and Formula 2 induce liquid crystal alignment in the side chain direction. Thereby, processability and chemical resistance are improved, and stability can be obtained with respect to a printing process, a rubbing process, and a washing process.

In addition, the liquid crystal orientation induced in the side chain direction facilitates the adjustment of the pretilt angle due to the change in the content of the functional diamine. This property is also suitable for the vertical alignment mode for orienting the liquid crystal in the vertical direction, and has a good influence on the stability of the vertical alignment force.

In addition, when the aromatic diamine is mixed and used together with the above two functional diamines, it is easy to adjust the pretilt angle of the liquid crystal molecules, and has excellent alignment property, and thus the vertical alignment force and the ease of dropping the liquid crystal are not generated. It can have, and also maintains the adhesive force between the sealant and the alignment film.

In addition, it has excellent chemical resistance, stable liquid crystal alignment force, electrochemical properties, and reliability for afterimages, and is excellent in processability, so that the liquid crystal alignment property is not affected by the cleaning solvent used in the cleaning process. The alignment force is not deformed, and the alignment layer is easily removed during the upper / lower substrate rework process that is performed due to the printing failure during the LCD panel manufacturing process.

(1-1) functional diamine

(1-1-1) First Functional Diamine

As the first functional diamine, a compound represented by the following Chemical Formula 3 may be used.

(3)

In Chemical Formula 3,

R ₅ is a hydrogen atom; Substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

R ₆ is a substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₆ is an integer of 0 to 3.

The content of the first functional diamine may be 1 to 30 mol% with respect to the total diamine, preferably 2 to 15 mol% . When the content of the first functional diamine is included in the above range, the polyamic acid or polyimide prepared using the same includes the divalent organic group derived from the first functional diamine as the content. When the content of the first functional diamine is included in the above range, the prepared polyamic acid or polyimide polymer can also maintain the adhesion between the sealant and the alignment layer while ensuring both the vertical alignment force and the ease of liquid crystal dropping without the occurrence of liquid crystal dropping. .

(1-1-2) Second Functional Diamine

As the second functional diamine, a compound represented by the following Chemical Formula 4 may be used.

[Formula 4]

In Chemical Formula 4,

R ₇ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₈ , R ₉ and R ₁₀ are, independently from each other, -H, -CH ₃ or a halogen atom,

R ₁₁ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group,

R ₁₂ is a linear, branched or cyclic substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.

The content of the second functional diamine may be 1 to 40 mol%, and may be 2 to 20 mol% with respect to the total diamine. When the content of the second functional diamine is included in the above range, the polyamic acid or polyimide prepared using the same includes the divalent organic group derived from the second functional diamine as the content. When the content of the second functional diamine is included in the above range, the prepared polyamic acid or polyimide can also maintain the adhesion between the sealant and the alignment layer, while ensuring both the vertical alignment force and the ease of liquid crystal dropping do not occur liquid crystal dropping.

(1-2) aromatic diamine

Examples of the aromatic diamine include paraphenylenediamine (p-PDA), 4,4-methylenedianiline (MDA), 4,4-oxydianiline (ODA), metabisaminophenoxydiphenylsulfone (m-BAPS), Parabisaminophenoxydiphenylsulfone (p-BAPS), 2,2-bisaminophenoxyphenylpropane (BAPP), 2,2-bisaminophenoxyphenylhexafluoropropane (HF-BAPP), 1,4- Diamino-2-methoxybenzene, or a mixture of one or more thereof may be used, but is not limited thereto.

The amount of the aromatic diamine used may be 30 to 98 mol% with respect to the total diamine content, and may be used at 35 to 90 mol%. When the amount of the aromatic diamine is included in the above range, there is an advantage that the stability of the printable film is guaranteed .

The divalent organic group derived from the aromatic diamine may have a structure of at least one of compounds represented by the following Chemical Formulas 12 to 14.

[Formula 12]

 [Formula 13]

[Formula 14]

(In Chemical Formulas 12 to 14,

R ₆₁ , R ₆₃ , R ₆₄ , and R ₆₇ to R ₆₉ are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group; Or the alkyl group, aryl group, or heteroaryl group further comprising one of -O-, -COO-, -CONH- or -OCO-,

R ₆₂ , R ₆₅ , and R ₆₆ are each independently C (R ') (R''), such as O, SO ₂ , or C (CF ₃ ) ₂ , wherein R', and R '' are each independently Hydrogen atom; or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms,

n ₆₁ , n ₆₃ , n ₆₄ , and n ₆₇ to n ₆₉ are each independently an integer of 0 to 4,

n ₆₂ , n ₆₅ , and n ₆₆ are each independently an integer from 0 to 1)

(2-1) acid dianhydride

As the acid dianhydride, an aliphatic cyclic acid dianhydride, an aromatic acid dianhydride, or a mixture thereof can be used. When an aliphatic cyclic acid dianhydride and an aromatic acid dianhydride are mixed and used as the acid dianhydride, their contents may be 5 to 90 mol% and 10 to 95 mol%, respectively.

(2-1-1) Aliphatic Cyclic Acid Anhydride

When aliphatic cyclic acid dianhydride is used to prepare polyamic acid or soluble polyimide polymer, it is insoluble in general organic solvents, low permeability in visible region due to charge transfer complex, due to high molecular structure and high polarity. Problems such as deterioration of electro-optic properties can be compensated for.

As the aliphatic cyclic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid is an anhydride (CBDA), 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexene-1,2 -Dicarboxylic acid 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 Anhydrides, or a mixture of one or more thereof may be used, but is not limited thereto.

The tetravalent organic group derived from the aliphatic cyclic acid dianhydride may have a structure of at least one of the compounds represented by the following Chemical Formulas 15 to 19.

[Formula 15]

 [Formula 16]

[Formula 17]

[Formula 18]

 [Formula 19]

(In Chemical Formula 15 to 19,

R ₇₀ is a hydrogen atom; Substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₇₀ is an integer of 0 to 3,

R ₇₁ to R ₇₇ each independently represent a hydrogen atom; Substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group.)

(B-1-1-2) aromatic acid dianhydride

The liquid crystal aligning film formed to a thickness of 800 to 1000 mm by using a liquid crystal aligning agent comprising a polyamic acid or a soluble polyimide polymer prepared using an aromatic acid dianhydride can withstand the rubbing process, and is heat resistant to a high temperature processing process of 200 ° C. or higher. It can have excellent chemical resistance, maintaining.

The aromatic acid dianhydrides include pyromellitic dianhydride (PMDA), nonphthalic dianhydride (BPDA), oxydiphthalic dianhydride (ODPA), benzophenone tetracarboxylic dianhydride (BTDA), and hexafluoroisopropylidene diphthalic acid. Dianhydride (6-FDA), 3,4-dicarboxyl-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride (TDA) or a mixture of one or more thereof may be used, but is not limited thereto. It is not.

The tetravalent organic group derived from the aromatic acid dianhydride may have a structure of at least one of a compound represented by Formula 20, a compound represented by Formula 21, and a compound represented by Formula 22.

[Formula 20]

[Formula 21]

[Formula 22]

(In Chemical Formula 20 to Chemical Formula 22

R ₈₁ and R ₈₂ are each independently a hydrogen atom; Substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

R ₈₄ , and R ₈₅ are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₇₄ , and n ₇₅ are each independently an integer of 0 to 3,

R ₈₃ is -O-; -CO-; Substituted or unsubstituted alkylene group (for example -C (CF ₃ ) _2- ); A substituted or unsubstituted cycloalkylene group; Or a substituted or unsubstituted heterocycloalkylene group, n ₂₃ is an integer of 0 or 1,

R ₈₆ and R ₈₇ are each independently a substituted or unsubstituted alkyl group; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₈₄ , and n ₈₅ are each independently an integer of 0 to 2)

The amount of the aromatic acid dianhydride may be 10 to 95 mol%, or 50 to 80 mol% with respect to the total content of the acid dianhydride. When the content of the aromatic acid dianhydride is included in the above range, it is possible to improve the mechanical properties and heat resistance characteristics of the liquid crystal alignment film formed, it is possible to improve the electrical properties such as voltage retention.

The polyamic acid or soluble polyimide included in the liquid crystal aligning agent according to the embodiment of the present invention preferably has a number average molecular weight of 10,000 to 500,000 g / mol, and the glass transition temperature is 200 to 350 when imidization is performed. It has a range of ℃. When the number average molecular weight is less than 10,000 g / mol, thermal stability, chemical resistance, and the like as the alignment layer are reduced, which is not preferable. If the number average molecular weight exceeds 500,000 g / mol, the viscosity may be too high to form a uniform film due to poor printability.

Liquid crystal aligning agent according to an embodiment of the present invention by containing an organic group from the two functional diamines of the formula (1) and formula (2) while maintaining the vertical alignment force which is an advantage of the conventional liquid crystal aligning agent for VA mode, the liquid crystal is a conventional problem The problem of liquid crystal dropping in a liquid crystal panel at the time of dripping and adhesiveness of a panel upper / lower board | substrate can be solved.

In the liquid crystal dropping step, an appropriate amount of liquid crystal is dropped on the lower plate of the panel, and the upper and lower substrates are bonded together under vacuum conditions, and the liquid crystal dropping is performed while the dropped liquid crystal fills the empty space of the panel. Liquid crystal dropping problem of the liquid crystal aligning agent for the conventional VA mode is a liquid crystal aligning agent using a functional diamine containing a long chain alkyl chain, or a functional diamine containing a large spacer and a short chain alkyl chain, designed to maintain the vertical alignment force Can occur in In the case of a liquid crystal aligning agent including a functional diamine including a long chain alkyl chain, when applied to the liquid crystal alignment layer, the hydrophobicity of the surface increases, so that the dropping of the dropped liquid crystal does not occur smoothly, and an unfilled area is generated. The same failure may occur. In addition, an increase in hydrophobicity may cause a problem that the adhesion between the sealant and the alignment layer is lowered.

On the other hand, in the case of a liquid crystal aligning agent using a functional diamine containing a large spacer and a short chain alkyl chain, the hydrophobicity of the surface is not so high when applied to the liquid crystal aligning film, so there is no problem in liquid crystal dropping during the liquid crystal dropping process, and also the panel Adhesiveness of the upper and lower substrates, that is, adhesiveness between the sealant and the alignment layer may be secured, but a vertical alignment force that does not cause liquid crystal dropping stains may not be secured, and defects such as alignment stains may occur.

In addition, when applying a liquid crystal aligning agent containing one conventional functional diamine, there is a high possibility that the adhesion of the upper and lower panel substrates may be low, the panel substrate may be easily separated.

In contrast, when the polyamic acid or polyimide including the organic groups derived from Formulas 3 and 4 according to one embodiment of the present invention is used as the liquid crystal aligning agent, the vertical alignment force and the ease of dropping the liquid crystal are not generated. Both can be secured and the adhesive force between the sealant and the alignment film can also be maintained.

In addition, it has excellent chemical resistance, stable liquid crystal alignment force, electro-optical characteristics, and reliability for afterimages, and excellent processability, so that the liquid crystal alignment property is not affected by the cleaning solvent used in the cleaning process, and the liquid crystal can be applied to long-term voltage application. The alignment force is not deformed, and the alignment layer is easily removed during the upper / lower substrate rework process that is performed due to the printing failure during the LCD panel manufacturing process. That is, the liquid crystal aligning agent is a liquid crystal aligning agent which solves the problem of the conventional liquid crystal aligning agent and has better characteristics in various aspects.

(3) solvent

As the solvent, any solvent capable of dissolving polyamic acid or polyimide according to one embodiment of the present invention may be used .

The solvent is aprotic such as N-methyl-2-pyrrolidone (NMP), gamma-butyrolactone (GBL), dimethylformamide (DMF), dimethylacetamide (DMAc), tetrahydrofuran (THF) and the like. Solvents or N, N-dimethyl acetamide, N, N-dimethyl formamide, dimethyl sulfoxide, γ-butyrolactone, and metacresol, phenol, halogenated phenol and the like can be used. The aprotic solvent can be suitably used as the solvent.

The solvent may further include an alcohol, ketone, ester, ether, hydrocarbon, or halogenated hydrocarbon, which is a poor solvent, in an appropriate ratio as long as the soluble polyimide polymer is not precipitated. This is because the poor solvents lower the surface energy of the liquid crystal aligning agent to improve the spreadability and flatness during application.

The poor solvent is preferably used in the range of 1 to 90% by volume with respect to the total solvent, more preferably in the range of 1 to 70% by volume.

Specific examples of the poor solvent include methanol, ethanol, 2-butoxy ethanol, isopropanol, cyclo hexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, acetone, methyl ethyl ketone, cyclohexanone, acetic acid Methyl, ethyl acetate, butyl acetate, diethyl hydroxide, butyl cellulsolve, malonic ester, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol phenyl ether, ethylene glycol phenyl methyl ether, ethylene glycol phenyl Ethyl ether, ethylene glycol dimethylethyl, diethylene glycol dimethylethyl, 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, ethyl Ethylene glycol ethyl ether acetate, 4-hydroxy-4-methyl-2-pentanone, 2-hydroxy propionate ethyl, 2-hydroxy-2-methyl propionate, ethoxy ethyl acetate, hydroxy ethyl acetate, 2- Methyl hydroxy-3-methyl butanoate, methyl 3-methoxy propionate, ethyl 3-methoxy propionate, ethyl 3-ethoxy propionate, methyl 3-ethoxy propionate, methyl methoxy butanol, ethyl methoxy butanol, methyl e Methoxy butanol, ethyl ethoxy butanol, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichloro butane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene , Xylene, and combinations thereof.

The excellent solubility of the polyamic acid or soluble polyimide is considered to have a great effect of the functional diamine in which three benzene rings have three-dimensional repulsion and three-dimensional presence in terms of introduction of aliphatic cyclic acid dianhydride and molecular structure. . In recent years, the liquid crystal aligning agent can be more preferably used in the situation where the printability of the liquid crystal aligning agent is very important due to the enlargement, high resolution and high quality of the liquid crystal display element.

The content of the solvent in the composition for forming a liquid crystal alignment film is not particularly determined, but may be used so that the solid content of the liquid crystal alignment agent is 1 to 30% by weight. The content of the solvent according to another embodiment of the present invention may be used so that the solid content of the liquid crystal aligning agent is 2 to 15% by weight, or may be used to be 4 to 10% by weight. When the content of the solid content is within the above range, it is not influenced by the surface of the substrate during printing so that the uniformity of the film can be properly maintained, and the appropriate viscosity can be maintained, thereby reducing the uniformity of the film formed during printing due to the high viscosity. It can prevent, and can show appropriate transmittance | permeability.

(4) other additives

Liquid crystal aligning agent according to an embodiment of the present invention may further include an epoxy compound, a silane coupling agent or a surfactant. The epoxy compound is used for improving reliability and electro-optical properties, and the epoxy compound may use one or more epoxy compounds having 2 to 4 epoxy functional groups.

The epoxy compound may be included in an amount of 0.01 to 50 parts by weight and 1 to 30 parts by weight based on 100 parts by weight of the liquid crystal aligning agent. When the content of the epoxy compound is included in the above range, it is possible to improve the reliability and electro-optical properties, while showing the proper printability and flatness when applied to the substrate.

Specific examples of the epoxy compound include N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM), N, N, N', N'-tetraglycidyl -4,4'-diaminodiphenylethane, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylpropane, N, N, N', N'-tetragly Cydyl-4,4'-diaminodiphenylbutane, N, N, N ', N'-tetraglycidyl-4,4'-diaminobenzene, and the like, but are not limited thereto.

The silane coupling agent or surfactant may improve adhesion to the substrate, and improve flatness and film coating property.

Liquid crystal alignment film according to another embodiment of the present invention is manufactured using the liquid crystal aligning agent.

The liquid crystal photoalignment film can be formed by applying a liquid crystal photoalignment agent to a substrate. Examples of the method for applying the liquid crystal alignment agent to the substrate include a spin coat method, a flexographic printing method and an inkjet method. Especially, the flexographic printing method can be used suitably because it is excellent in the uniformity of the formed coating film and easy to enlarge.

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. Moreover, it is preferable to use the board | substrate with which the ITO electrode etc. for liquid crystal drive were formed from a viewpoint of the simplification of a manufacturing process.

The composition for forming a liquid crystal alignment film is uniformly coated on a substrate in order to increase the uniformity of the coating film, and then, for 1 to 100 minutes at room temperature to 200 ° C, preferably 30 to 150 ° C, more preferably 40 to 120 ° C. It is preferable to perform drying. By adjusting the volatilization degree of each component of the composition for liquid crystal aligning film formation through the said temporary drying, the coating film which is uniform and there is no deviation can be obtained.

Thereafter, the liquid crystal aligning film can be formed by baking for 5 to 300 minutes at a temperature of 80 to 300 ° C, preferably 120 to 280 ° C to completely evaporate the solvent.

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

1 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display 1 according to the exemplary embodiment of the present invention includes a lower panel 100, an upper panel 200, and a liquid crystal layer 3.

The lower panel 100 includes a gate conductor including a plurality of gate lines (not shown) and a plurality of storage electrodes 133 on an upper surface of the first substrate 110. . On the gate conductor, a gate insulating layer 140, a plurality of semiconductors 154, a plurality of pairs of ohmic contacts 163 and 165, a plurality of source electrodes 173, And a plurality of drain electrodes 175 are formed in this order.

One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the semiconductor 154 form one thin film transistor (TFT).

A passivation layer 180 is formed on the exposed portion of the semiconductor 154, the source electrode 173, the drain electrode 175, and the gate insulating layer 140. A plurality of pixel electrodes 191 are formed on the passivation layer 180.

Next, the upper panel 200 will be described.

In the upper panel 200, a light blocking member 220 is formed on the second substrate 210. A plurality of color filters 230 are formed on the second substrate 210 and the light blocking member 220, and an overcoat 250 is formed on the color filters 230. The overcoat 250 may prevent the color filter 230 from being exposed to the liquid crystal layer 3, and the overcoat 250 may be omitted.

The first liquid crystal alignment layer 12 and the second liquid crystal alignment layer 22 are formed on the pixel electrode 191 of the lower panel 100 and the common electrode 270 of the upper panel 200, respectively. The first liquid crystal alignment layer 12 and the second liquid crystal alignment layer 22 are manufactured by using the liquid crystal alignment agent according to the embodiment of the present invention.

In FIG. 1, the liquid crystal alignment layers 12 and 22 are formed on both the lower panel 100 and the upper panel 200. However, the liquid crystal alignment layers 12 and 22 may be the upper panel 200 or the lower panel. It may be formed only in any one of the (100).

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and thus the present invention is not limited thereto.

(Manufacture of liquid crystal aligning agent)

(Example 1)

0.93 mol of 4,4-methylenedianiline, 0.02 mol of 3,5-diaminophenyldecyl succinimide while passing nitrogen through a four-necked flask equipped with a stirrer, a thermostat, a nitrogen gas injector and a cooler 0.05 moles of diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl (4,8,12-trimethyl-tridecyl) chroman-6-yl ester was added and N-methyl-2 was added. -Pyrrolidone was added to dissolve to prepare a diamine solution.

1.00 mol of solid 3,4-dicarboxyl-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride was added to the diamine solution, followed by vigorous stirring. Solid content in the obtained liquid was 15 weight% in weight ratio. The reaction was carried out for 4 hours while keeping the obtained liquid at a temperature below 25 ° C. The polyamic acid produced according to this reaction was recovered. In this case, the number average molecular weight of the prepared polyamic acid was 180,000 g / mol.

N-methyl-2-pyrrolidone and 2-butoxy ethanol, which are organic solvents, were added to the prepared polyamic acid to a final mixing ratio of 80:20 by volume, and stirred at room temperature for 24 hours to give a solid content of 6% by weight of polyamic acid. The solution was prepared.

(Example 2)

To the polyamic acid solution prepared in Example 1, 3.0 mol of acetic anhydride and 5.0 mol of pyridine were added and heated to 80 ° C., followed by reaction for 6 hours, and the catalyst and solvent were removed by vacuum distillation to obtain a solid content of 20. A wt% soluble polyimide polymer was prepared. In this case, the number average molecular weight of the polyimide polymer prepared was 90.000 g / mol.

N-methyl-2-pyrrolidone and 2-butoxy ethanol, which are organic solvents, were added to the prepared soluble polyimide polymer so as to have a final mixing ratio of 80:20 by volume, and stirred at room temperature for 24 hours to give a solid content of 6% by weight. Soluble polyimide polymer solution was prepared.

(Example 3)

0.88 mol of 4,4-methylenedianiline, 0.02 mol of 3,5-diaminophenyldecyl succinimide, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl (4 A polyamic acid solution was prepared in the same manner as in Example 1 except that 0.10 mol of 8,12-trimethyl-tridecyl) chroman-6-yl ester was used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Example 4)

A soluble polyimide solution was prepared in the same manner as in Example 2, except that the polyamic acid solution prepared in Example 3 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Example 5)

0.85 mol 4,4-methylenedianiline, 0.05 mol 3,5-diaminophenyldecyl succinimide, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl (4 A polyamic acid solution was prepared in the same manner as in Example 1 except that 0.10 mol of 8,12-trimethyl-tridecyl) chroman-6-yl ester was used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Example 6)

A soluble polyimide polymer solution was prepared in the same manner as in Example 2, except that the polyamic acid solution prepared in Example 5 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Comparative Example 1)

4,4-methylenedianiline 0.90 mol, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl (4,8,12-trimethyl-tridecyl) chroman-6 A polyamic acid solution was prepared in the same manner as in Example 1, except that 0.10 mole of the nitrile ester and 3,5-diaminophenyldecyl succinimide were not used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Comparative Example 2)

A soluble polyimide polymer solution was prepared in the same manner as in Example 2, except that the polyamic acid solution prepared in Comparative Example 1 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Comparative Example 3)

4,4-methylenedianiline 0.85 mole, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl (4,8,12-trimethyl-tridecyl) chroman-6 A polyamic acid solution was prepared in the same manner as in Comparative Example 1, except that 0.15 mol of -yl ester and 3,5-diaminophenyldecyl succinimide were not used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Comparative Example 4)

A soluble polyimide polymer solution was prepared in the same manner as in Comparative Example 2 except that the polyamic acid solution prepared in Comparative Example 3 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Comparative Example 5)

0.95 mol of 4,4-methylenedianiline, 0.05 mol of 3,5-diaminophenyldecyl succinimide, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl ( A polyamic acid solution was prepared in the same manner as in Comparative Example 1 except that 4,8,12-trimethyl-tridecyl) chroman-6-yl ester was not used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Comparative Example 6)

A soluble polyimide polymer solution was prepared in the same manner as in Comparative Example 2 except that the polyamic acid solution prepared in Comparative Example 5 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Comparative Example 7)

0.90 mol of 4,4-methylenedianiline, 0.10 mol of 3,5-diaminophenyldecyl succinimide, 3,5-diaminobenzoic acid-2,5,7,8-tetramethyl-2-yl A polyamic acid solution was prepared in the same manner as in Comparative Example 1 except that (4,8,12-trimethyl-tridecyl) chroman-6-yl ester was not used. The number average molecular weight of the polyamic acid produced at this time was 180,000 g / mol.

(Comparative Example 8)

A soluble polyimide polymer solution was prepared in the same manner as in Comparative Example 2 except that the polyamic acid solution prepared in Comparative Example 7 was used. The number average molecular weight of the polyimide polymer prepared at this time was 90,000 g / mol.

(Liquid crystal aligning agent evaluation)

The vertical alignment force of the liquid crystal aligning agents prepared in Examples 1 to 6 and Comparative Examples 1 to 8 was applied to each of the liquid crystal alignment layers, and then a liquid crystal test cell was manufactured while performing a rubbing process of 0.25T once, and a pretilt angle was obtained. Was measured and compared.

If the vertical alignment force is high, the pretilt angle is high even after the rubbing process is applied. The ease of liquid crystal dropping should be compared with the non-dropping area generated when the liquid crystal dropping is not smooth, but due to the subjective criterion, objective alternative characteristics were introduced and measured by comparing the contact angle between the liquid crystal and the alignment layer.

Finally, the adhesion between the alignment layer and the sealant was prepared by measuring empty cells without injecting liquid crystal, and measuring the adhesive force (Kgf) by using a dye shear stress equipment.

The measured pretilt angles, liquid crystal contact angles, and adhesive strengths are shown in Table 1 below.

Compound of formula 3
(mole%) Compound of formula 4
(mole%) Pretilt
(°) LCD contact angle
(°) Adhesion
(kgf) Required characteristic satisfaction
(○ / X) Example 1 2
5
86.5 4 30 ○
Example 2 86.0 5 29 Example 3 2
10
87.0 6 28 ○
Example 4 86.0 7 27 Example 5 5
10
88.0 8 27 ○
Example 6 87.5 9 26 Comparative Example 1 -
10
85.0 5 30 X
Comparative Example 2 84.5 6 29 Comparative Example 3 -
15
87.5 10 24 X Comparative Example 4 86.5 12 23 Comparative Example 5 5
-
85.0 11 28 X Comparative Example 6 84.5 13 26 Comparative Example 7 10
-
87.0 13 24 X
Comparative Example 8 86.0 15 23

-Requirements for satisfying the required characteristics are as follows.

Pretilt angle: ≥ 86.0 degrees,

LCD contact angle: ≤ 10 degrees,

Adhesion: ≥ 25 Kgf

As shown in Table 1, it can be seen that in Examples 1 to 6 including both the first functional diamine represented by the formula (3) and the second functional diamine represented by the formula (4), all of the required properties are satisfied. On the contrary, in Comparative Examples 1 to 8 including only one of the first functional diamine and the second functional diamine, it can be seen that the required characteristics are not satisfied.

 The present invention is not limited to the above embodiments, but may be manufactured in various forms, and a person skilled in the art to which the present invention pertains has another specific form without changing the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be practiced as. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: liquid crystal display device 3: liquid crystal layer

12: first liquid crystal alignment film 22: second liquid crystal alignment film

100: lower display panel 110: first substrate

175: drain electrode 191: pixel electrode

200: upper display panel 210: second substrate

230: color filter 270: common electrode

Claims (6)

A polymer selected from the group consisting of a polyamic acid represented by Formula 1, a polyimide polymer represented by Formula 2, and a combination thereof Liquid crystal aligning agent containing. [Formula 1]

[Formula 2]

(In Chemical Formulas 1 to 2, R ₁ and R ₃ are each independently a tetravalent organic group derived from an acid dianhydride selected from the group consisting of aliphatic cyclic acid dianhydrides, aromatic acid dianhydrides, and combinations thereof; R ₂ and R ₄ are each independently a first functional diamine represented by the following general formula (3), a second functional diamine represented by the following general formula (4), and a divalent organic group derived from an aromatic diamine.) (3)

In Chemical Formula 3, R ₅ is a hydrogen atom; A substituted or unsubstituted alkyl group having 1 to 31 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, R ₆ is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; Substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group, n ₆ is an integer of 0 to 3. [Formula 4]

In Chemical Formula 4, R ₇ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group, R ₈ , R ₉ and R ₁₀ are, independently from each other, -H, -CH ₃ or a halogen atom, R ₁₁ is a single bond, -O-, -COO-, -CONH-, -OCO-, an aryl group, an alicyclic ring group or a heterocyclic group, R ₁₂ is a linear, branched or cyclic substituted or unsubstituted alkyl group having 1 to 10 carbon atoms. The method of claim 1, The polyamic acid and soluble polyimide 1 to 30 mol% of divalent organic groups derived from the first functional diamine represented by Formula 3, and 1 to 40 mol% of divalent organic groups derived from the second functional diamine represented by Formula 4 above. It is a liquid crystal aligning agent. The method of claim 1, The polyamic acid and soluble polyimide 2 to 15 mol% of divalent organic groups derived from the first functional diamine represented by Formula 3, and 2 to 20 mol% of functional diamines derived from the second functional diamine represented by Formula 4 above. Phosphorus liquid crystal aligning agent. The method of claim 1, The polyamic acid or soluble polyimide has a number average molecular weight of 10,000 to 500,000 g / mol liquid crystal aligning agent. The liquid crystal aligning film manufactured by apply | coating the liquid crystal aligning agent as described in any one of Claims 1-4 to a board | substrate. A liquid crystal display device comprising the liquid crystal alignment film according to claim 5.

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