KR20200023103A - Liquid crystal alignment film, method of preparing liquid crystal alignment film, and liquid crystal display device using the same - Google Patents

Abstract

The present invention relates to a liquid crystal aligning film having a high contact angle average change rate value for a period of time, a production method of a liquid crystal aligning film, and a liquid crystal display device using the same. The liquid crystal aligning film comprises a polymer including at least one selected from the group consisting of a polyimide repeating unit, a polyamic acid ester repeating unit, and a polyamic acid repeating unit.

Description

A liquid crystal aligning film, a manufacturing method of a liquid crystal aligning film, and a liquid crystal display device using the same TECHNICAL FIELD, and the liquid crystal display device using the same.

The present invention relates to a liquid crystal alignment layer, a method of manufacturing a liquid crystal alignment layer, and a liquid crystal display device using the same, which can increase the yield of a panel through excellent cleaning power, and improves liquid crystal alignment characteristics and electrical characteristics.

In the liquid crystal display device, the liquid crystal alignment film plays a role of orienting the liquid crystal in a constant direction. Specifically, the liquid crystal alignment layer acts as a director in the arrangement of the liquid crystal molecules to allow proper alignment when the liquid crystal is moved by an electric field to form an image. In order to obtain uniform brightness and high contrast ratio in the liquid crystal display, it is essential to orient the liquid crystal uniformly.

However, in recent years, as the required performance of the liquid crystal display device has been improved and the LCD panel has been enlarged in size, a manufacturing method of an ODF (one drop fill) process method of dropping liquid crystal onto a substrate before attaching the glass substrate becomes inevitable.

For this purpose, the cleaning with respect to a liquid crystal aligning film is necessarily required before the ODF process which drops a liquid crystal on a board | substrate. The process of cleaning and removing foreign matter on the surface of the liquid crystal aligning film has an important influence on the yield, transmittance, initial alignment, afterimage, electrical characteristics, and long-term reliability of the panel.

Accordingly, it is possible to increase the yield of the panel through excellent cleaning power and to develop a liquid crystal alignment layer having improved liquid crystal alignment characteristics and electrical characteristics.

The present invention relates to a liquid crystal alignment layer that can increase the yield of the panel through excellent cleaning power, and improved liquid crystal alignment characteristics and electrical characteristics.

Moreover, this invention is providing the manufacturing method of the said liquid crystal aligning film.

Moreover, this invention is providing the liquid crystal display element containing the said liquid crystal aligning film.

In order to solve the above problems, in the present specification, a polymer containing at least one member selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units, wherein A liquid crystal aligning film with a contact angle average change rate of 0.035 degrees / sec or more is provided.

[Equation 1]

Average change rate of first contact angle (° / sec) = (A ₀ -A ₁ ) / 50

In Equation 1, A ₀ is the contact angle of the liquid crystal alignment layer at the first time point (0 second) when 1 μl of ultrapure water is dropped onto the surface of the liquid crystal alignment film, and A ₁ is the first time point when 1 μl of ultrapure water is dropped onto the surface of the liquid crystal alignment film. It is the contact angle of the liquid crystal aligning film after 50 second from (0 second).

In the present specification, the liquid crystal aligning agent composition comprising a polymer comprising at least one member selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units to form a coating film; Drying the coating film; Irradiating or rubbing the light on the dried coating layer to perform alignment; And it provides a method for producing a liquid crystal alignment film comprising the step of curing the alignment-treated coating film.

In the present specification, a liquid crystal display device including a liquid crystal alignment film is also provided.

Hereinafter, a liquid crystal alignment film, a method of manufacturing a liquid crystal alignment film, and a liquid crystal display device using the same according to a specific embodiment of the present invention will be described in detail.

Unless otherwise specified herein, the following terms may be defined as follows.

In the present specification, when a part "includes" a certain component, it means that it may further include other components, without excluding other components unless specifically stated otherwise.

In the present specification, examples of the substituent are described below, but are not limited thereto.

In the present specification, the term "substituted" means that another functional group is bonded to the hydrogen atom in the compound, and the position to be substituted is not limited to a position where the hydrogen atom is substituted, that is, a position where a substituent may be substituted, and when two or more are substituted , Two or more substituents may be the same or different from each other.

As used herein, the term "substituted or unsubstituted" is deuterium; Halogen group; Cyano group; Nitro group; Hydroxyl group; Carbonyl group; Ester group; Imide group; Amide group; Primary amino group; Carboxyl groups; Sulfonic acid groups; Sulfonamide groups; Phosphine oxide groups; An alkoxy group; Aryloxy group; Alkyl thioxy group; Arylthioxy group; Alkyl sulfoxy groups; Aryl sulfoxy group; Silyl groups; Boron group; Alkyl groups; Cycloalkyl group; Alkenyl groups; Aryl group; Aralkyl group; Ar alkenyl group; Alkylaryl group; Alkoxy silyl alkyl group; Aryl phosphine group; Or substituted or unsubstituted with one or more substituents selected from the group consisting of heterocyclic groups including one or more of N, O, and S atoms, or two or more substituents connected to the substituents exemplified above. . For example, "a substituent to which two or more substituents are linked" may be a biphenyl group. That is, the biphenyl group may be an aryl group or may be interpreted as a substituent to which two phenyl groups are linked.

, 또는

는 다른 치환기에 연결되는 결합을 의미하고, 직접결합은 L 로 표시되는 부분에 별도의 원자가 존재하지 않은 경우를 의미한다. In this specification,

, or

Means a bond connected to another substituent, and a direct bond means a case where no separate atom is present in a portion represented by L.

In the present specification, the alkyl group is a monovalent functional group derived from an alkane, which may be linear or branched, and the number of carbon atoms of the linear alkyl group is not particularly limited but is preferably 1 to 20. In addition, the branched alkyl group has 3 to 20 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n -Pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl , n-heptyl, 1-methylhexyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl- Propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, 2,6-dimethylheptan-4-yl, and the like. The alkyl group may be substituted or unsubstituted.

In the present specification, the halo alkyl group refers to a functional group in which a halogen group is substituted with the aforementioned alkyl group, and examples of the halogen group include fluorine, chlorine, bromine or iodine. The haloalkyl group may be substituted or unsubstituted.

In the present specification, the cycloalkyl group is a monovalent functional group derived from cycloalkane, which may be monocyclic or polycyclic, and is not particularly limited, but has 3 to 20 carbon atoms. According to another exemplary embodiment, the cycloalkyl group has 3 to 10 carbon atoms. Specifically cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3, 4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, bicyclo [2,2,1] heptyl, and the like, but are not limited thereto. The cycloalkyl group may be substituted or unsubstituted.

In the present specification, the aryl group is a monovalent functional group derived from arene, but is not particularly limited, but preferably has 6 to 20 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. The aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc. as the monocyclic aryl group, but is not limited thereto. The polycyclic aryl group may be a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, perylenyl group, chrysenyl group, fluorenyl group, and the like, but is not limited thereto. The aryl group may be substituted or unsubstituted.

In the present specification, the alkylene group is a divalent functional group derived from an alkane, and the description of the aforementioned alkyl group may be applied except that these are divalent functional groups. For example, it may be a methylene group, an ethylene group, a propylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, a pentylene group, a hexylene group, or the like as a straight chain or branched type. The alkylene group may be substituted or unsubstituted.

In the present specification, a multivalent organic group is a residue in a form in which a plurality of hydrogen atoms bonded to an arbitrary compound are removed, and examples thereof include a divalent organic group, a trivalent organic group, and a tetravalent organic group. . In one example, a tetravalent organic group derived from cyclobutane means a moiety in the form in which any four hydrogen atoms bonded to cyclobutane have been removed.

In the present specification, a direct bond or a single bond means that no atom or atom group exists at a corresponding position, and thus is connected by a bond line. Specifically, it means a case where no separate atom exists in the moiety represented by L ₁ , L ₂ in the formula.

In this specification, a weight average molecular weight means the weight average molecular weight of polystyrene conversion measured by the GPC method. In the process of measuring the weight average molecular weight of polystyrene conversion measured by the GPC method, it is possible to use a detector and an analytical column, such as a conventionally known analytical device, a differential index detector, and the like. Conditions, solvents and flow rates can be applied. As specific examples of the measurement conditions, using a Waters PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300 mm length column, the evaluation temperature is 160 ° C. and 1,2,4-trichlorobenzene is used as the solvent. The flow rate is 1 mL / min, the sample is prepared at a concentration of 10 mg / 10 mL, then supplied in an amount of 200 μL, and the value of Mw can be determined using a calibration curve formed using a polystyrene standard. As for the molecular weight of the polystyrene standard, nine species of 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000,000 were used.

Hereinafter, the present invention will be described in more detail.

I. Liquid crystal alignment film

According to an embodiment of the present invention, a polyimide repeating unit, a polyamic acid ester repeating unit, and a polymer comprising at least one selected from the group consisting of polyamic acid repeating unit, the first contact angle average change rate according to Equation 1 The liquid crystal aligning film which is this 0.035 degrees / sec or more can be provided.

When the first contact angle average change rate according to Equation 1 satisfies 0.035 ° / sec or more, as in the liquid crystal alignment layer of the embodiment, the present inventors can significantly lower the contact angle within a short time, thereby providing high wettability. As a result, it was confirmed through experiments that excellent surface cleaning effects can be achieved during ultrapure water cleaning, and completed the invention.

Particularly, the liquid crystal alignment layer of the embodiment satisfies a specific property such that the first contact angle average change rate according to Equation 1 is 0.035 ° / sec or more, wherein the liquid crystal alignment layer has a divalent organic group represented by Formula 4 below. The polyimide repeating unit, the polyamic acid ester repeating unit, and the polyamic acid repeating unit according to one or more selected from the group consisting of.

[Formula 4]

In Formula 4, at least one of Q ₁ to Q ₈ is nitrogen, the remainder is carbon, D is -NR'- or -O-, and R 'is hydrogen or an alkyl group having 1 to 6 carbon atoms.

The inventors include one or more selected from the group consisting of a polyimide repeating unit, a polyamic acid ester repeating unit, and a polyamic acid repeating unit incorporating a divalent organic group represented by Formula 4 as in the liquid crystal alignment layer of the embodiment. If not, the experiment confirmed that the first contact angle average change rate according to Equation 1 does not satisfy a specific physical property of 0.035 ° / second or more through experiments and completed the invention.

Specifically, the liquid crystal alignment layer of the embodiment may have a first contact angle average change rate according to Equation 1 of 0.035 ° / sec or more. More specifically, the first contact angle average change rate according to Equation 1 is at least 0.035 ° / sec, or at least 0.040 ° / sec, at least 0.045 ° / sec, or at least 0.050 ° / sec, or at least 0.055 ° / sec, or Or at least 0.060 ° / sec, or at least 0.065 ° / sec, or at most 0.100 ° / sec, or at most 0.095 ° / sec, or at most 0.090 ° / sec, or at most 0.085 ° / sec, or at most 0.080 ° / sec.

More preferably, the first contact angle average change rate according to Equation 1 is 0.060 ° / sec to 0.080 ° / sec, or 0.062 ° / sec to 0.078 ° / sec, or 0.070 ° / sec to 0.080 ° / sec, or It may be from 0.060 ° / second to 0.070 ° / second.

Specifically, in Equation 1, A ₀ is a contact angle of the liquid crystal alignment layer at the first time point (0 second) when 1 μl of ultrapure water is dropped on the surface of the liquid crystal alignment layer, and 55 ° to 70 °, or 55.5 ° to 60 °, Or 55.9 ° to 56.3 °.

In Equation 1, A ₁ is a contact angle of the liquid crystal alignment layer after 50 seconds from the first time point (0 second) when 1 μl of ultrapure water is dropped on the surface of the liquid crystal alignment layer, and is 50 ° to 55 °, or 51 ° to 54 °. Or 52 ° to 53 °, or 52.4 ° to 52.8 °.

In the present specification, the contact angle means an angle formed by the dropped liquid droplets and the surface after dropping the liquid droplets on the solid surface, and in the above equation, the ultrapure water droplets are dropped on the surface of the liquid crystal alignment layer, and then the stopped ultrapure droplets and the liquid crystal are dropped. It means the angle which the surface of an oriented film makes.

In general, the higher the surface tension of the surface of the liquid crystal alignment layer, the better the wettability with respect to water and the smaller the contact angle. Therefore, the smaller the contact angle means that the hydrophilicity is good, the wettability is good, and the adhesion is good.

Therefore, when the liquid crystal alignment layer of the embodiment satisfies the above-described range by the first contact angle average change rate according to Equation 1, the contact angle can be greatly reduced within a short time, and excellent in ultrapure water cleaning based on high wettability. Surface cleaning effect can be implemented.

On the other hand, the average change rate of the second contact angle according to Equation 2 may be more than twice the average change rate of the third contact angle according to Equation 3 below.

[Equation 2]

2nd contact angle average rate of change (° / sec) = (A ₀ -A ₂ ) / 25

In Equation 2, A ₀ is the contact angle of the liquid crystal alignment film at the first time point (0 second) when 1 μl of ultrapure water is dropped onto the surface of the liquid crystal alignment film, and A ₂ is the first time point when 1 μl of ultrapure water is dropped onto the surface of the liquid crystal alignment film. It is the contact angle of the liquid crystal aligning film after 25 second from (0 second),

[Equation 3]

3rd contact angle average rate of change (° / sec) = (A ₂ -A ₁ ) / 25

In Equation 3, A ₂ is the contact angle of the liquid crystal alignment layer after 25 seconds from the first time point (0 second) when 1 μl of ultrapure water is dropped onto the surface of the liquid crystal alignment film, and A ₁ is 1 μl of ultrapure water dropping onto the surface of the liquid crystal alignment film. The contact angle of the liquid crystal aligning film after 50 second has passed from the initial time (0 second).

As the second contact angle average change rate according to Equation 2 has a value that is greater than or equal to two times greater than the third contact angle average change rate according to Equation 3, the liquid crystal alignment layer of the embodiment significantly lowers the contact angle within a short time. The surface cleaning efficiency can be improved during ultrapure water cleaning.

Specifically, the average change rate of the second contact angle according to Equation 2 may be 3.3 times or more than the average change rate of the third contact angle according to Equation 3 above.

More specifically, the ratio of the average change rate of the second contact angle according to Equation 2: The ratio of the average change rate of the third contact angle according to Equation 3 is 2: 1 to 5: 1, or 2.2: 1 to 4: 1, or 2.25: 1 to 3.5: 1, or 3.3: 1 to 5: 1, or 3.3: 1 to 4: 1.

In Equations 2 and 3, A ₂ may be in the range of 51.5 ° to 54 °, or 52 ° to 54 °, or 53 ° to 54 °.

Meanwhile, the liquid crystal alignment layer may include a polymer including at least one selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units.

That is, the polymer may include a copolymer of one polyamic acid repeat unit, one polyamic acid ester repeat unit, one polyimide repeat unit, or a mixture of two or more repeat units thereof.

Specifically, the polyimide repeating unit includes a repeating unit represented by the following Formula 1, and the polyamic acid ester repeating unit includes a repeating unit represented by the following Formula 2, and the polyamic acid repeating unit is represented by the following Formula 3 It may contain repeating units.

[Formula 1]

[Formula 2]

[Formula 3]

In Formulas 1 to 3, at least one of R ₁ and R ₂ is alkyl having 1 to 10 carbon atoms, the remainder is hydrogen, X ₁ to X ₃ are the same or different from each other, and each independently a tetravalent organic group, Y ₁ to Y ₃ are the same as or different from each other, and each independently a divalent organic group represented by the following general formula (4),

[Formula 4]

In Formula 4, at least one of Q ₁ to Q ₈ is nitrogen, the remainder is carbon, D is -NR'- or -O-, and R 'is hydrogen or an alkyl group having 1 to 6 carbon atoms.

In Chemical Formulas 1 to 3, X ₁ to X ₃ may be the same as or different from each other, and may each independently be a tetravalent organic group. The X ₁ to X ₃ may be a functional group derived from a polyamic acid, a polyamic acid ester, or a tetracarboxylic acid anhydride compound used in synthesizing a polyimide.

More specifically, X ₁ to X ₃ may be each independently one of a tetravalent organic group represented by the following formula (6).

[Formula 6]

In Formula 6, R ₅ to R ₁₀ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and L ₁ is a single bond, -O-, -CO-, -COO-, -S-, -SO-, -SO _2- , -CR ₁₁ R ₁₂ -,-(CH ₂ ) _t- , -O (CH ₂ ) _t O-, -COO (CH ₂ ) _t OCO-, -CONH-, phenylene or combinations thereof It is any one selected from the group consisting of, R _{One And} R ₁₁ And R _{12 Are} each independently hydrogen, an alkyl group having 1 to 10 carbon atoms or halo alkyl group, t is an integer of 1 to 10.

More preferably, X ₁ to X ₃ may be each independently an organic group represented by Chemical Formula 6-1 derived from pyromellitic dianhydride (PMDA).

[Formula 6-1]

Meanwhile, in Chemical Formulas 1 to 3, Y ₁ to Y ₃ may be the same as or different from each other, and may each independently be a divalent organic group. Y ₁ to Y ₃ may be a functional group derived from a polyamic acid, a polyamic acid ester, or a diamine compound used in synthesizing a polyimide.

As a specific example, Y ₁ to Y ₃ may be a divalent organic group represented by Chemical Formula 4.

In Formula 4, at least one of Q ₁ to Q ₈ is nitrogen, the remainder is carbon, D is -NR'- or -O-, and R 'is hydrogen or an alkyl group having 1 to 6 carbon atoms.

Specifically, in the organic group represented by Formula 4, at least one of Q ₁ to Q ₄ is nitrogen, the rest is carbon, Q ₅ to Q ₈ is carbon, D may be -NR'-. More preferably, in Formula 4, Q ₁ to Q ₄ of the Q ₂ is nitrogen and the remaining are carbon, Q ₅ to Q ₈ is carbon, D is the -NH- of the functional group of the general formula (V) to have.

[Formula 5]

More specifically, the functional group represented by Chemical Formula 5 satisfying the above may be a functional group represented by the following Chemical Formulas 5-1 to 5-3.

[Formula 5-1]

[Formula 5-2]

[Formula 5-3]

In addition, in the organic group represented by Formula 4, at least one of Q ₁ to Q ₄ is nitrogen, the remainder is carbon, at least one of Q ₅ to Q ₈ is nitrogen, the rest is carbon, and D is -NR Can be '-. In more preferably, the formula (4), wherein the Q ₁ to Q _4, Q ₄ of the nitrogen and the remainder carbon atoms, and the nitrogen of Q ₅ to Q ₈ Q _5, and the others are carbon, D is the -NH- The functional group of following formula (6) is mentioned.

[Formula 6]

More specifically, the functional group of Chemical Formula 6 satisfying the above may be a functional group represented by the following Chemical Formulas 6-1 to 6-2.

[Formula 6-1]

 [Formula 6-2]

As such, the divalent organic group represented by Chemical Formula 4 includes a divalent organic group represented by Chemical Formula 5, or a divalent organic group represented by Chemical Formula 6, so that the liquid crystal alignment layer of the embodiment is represented by Equation 1 The average change rate of the contact angle due to may satisfy 0.035 ° / sec or more.

In addition, in Chemical Formulas 1 to 3, at least one of R ₁ and R ₂ may be alkyl having 1 to 10 carbon atoms, and the rest may be hydrogen.

On the other hand, the liquid crystal aligning film of the embodiment may include an alignment cured product of the liquid crystal aligning agent composition comprising a polymer including at least one selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units. Can be. The said orientation hardened | cured material means the substance obtained through the orientation process and hardening process of the said liquid crystal aligning agent composition.

In a polymer including at least one member selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units included in the liquid crystal aligning agent composition, polyimide repeating units, polyamic acid ester repeating units, and polya The content regarding the mixed acid repeating unit includes all of the above-mentioned contents in the liquid crystal alignment layer.

In addition, the liquid crystal alignment layer of the embodiment may be a liquid crystal alignment layer manufactured according to the method of manufacturing a liquid crystal alignment layer described later. The content regarding the manufacturing method of a liquid crystal aligning film includes all the content mentioned later.

Although the thickness of the said liquid crystal aligning film is not specifically limited, For example, it can adjust freely within 0.01 micrometer-1000 micrometers. When the thickness of the liquid crystal alignment layer increases or decreases by a specific value, physical properties measured in the liquid crystal alignment layer may also change by a certain value.

Ⅱ. Manufacturing method of liquid crystal aligning film

In addition, the present invention is to form a coating film by applying a liquid crystal aligning agent composition comprising a polymer comprising at least one selected from the group consisting of polyimide repeating unit, polyamic acid ester repeating unit, and polyamic acid repeating unit ( Step 1); Drying the coating film (step 2); Irradiating or rubbing the light on the dried coating film to perform alignment treatment (step 3); And it provides a method for producing a liquid crystal alignment film, comprising the step (step 4) of the heat treatment of the alignment-treated coating film.

Step 1 is a step of applying the above-described liquid crystal aligning agent composition to a substrate to form a coating film. In a polymer including at least one member selected from the group consisting of polyimide repeating units, polyamic acid ester repeating units, and polyamic acid repeating units included in the liquid crystal aligning agent composition, polyimide repeating units, polyamic acid ester repeating units, and polya The content of the mixed acid repeating unit includes all of the details described above in the liquid crystal alignment layer of the embodiment.

The method for applying the liquid crystal aligning agent composition to the substrate is not particularly limited, and for example, screen printing, offset printing, flexographic printing, inkjet, or the like may be used.

The liquid crystal aligning agent composition may be dissolved or dispersed in an organic solvent. Specific examples of the organic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, and N-ethylpyrroli Don, N-vinylpyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy -N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methylnonyl ketone, methyl ethyl ketone, methyl isoamyl ketone , Methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl Ether, Ethylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Mod And the like propyl ether, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monoisopropyl ether acetate, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate. These may be used alone or in combination.

In addition, the liquid crystal aligning agent composition may further include other components in addition to the organic solvent. As a non-limiting example, when the liquid crystal aligning agent composition is applied, the uniformity and surface smoothness of the film thickness may be improved, or the adhesion between the liquid crystal aligning film and the substrate may be improved, or the dielectric constant or conductivity of the liquid crystal aligning film may be changed. Or an additive capable of increasing the compactness of the liquid crystal alignment layer. Such additives may be exemplified by various solvents, surfactants, silane-based compounds, dielectric or crosslinkable compounds.

Step 2 is a step of drying the coating film formed by applying the liquid crystal aligning agent composition to a substrate.

The drying step of the coating film may be carried out by heating means such as a hot plate, a hot air circulation furnace, an infrared furnace, or the like, and may be performed at a temperature of 50 ° C. to 150 ° C., or 50 ° C. to 100 ° C.

Step 3 is a step of performing alignment treatment by irradiating light or rubbing the dried coating film.

The light irradiation in the alignment treatment may be to irradiate polarized ultraviolet rays of 150 nm to 450 nm wavelength. At this time, the intensity of exposure varies depending on the kind of polymer for liquid crystal aligning agent, and energy of 10 mJ / cm 2 to 10 J / cm 2, preferably energy of 30 mJ / cm 2 to 2 J / cm 2 can be irradiated.

As the ultraviolet rays, a polarizer using a substrate coated with a dielectric anisotropic substance on a transparent substrate surface such as quartz glass, soda lime glass, soda lime free glass, a polarizing plate on which fine aluminum or metal wire is deposited, or quartz glass An orientation treatment is performed by irradiating polarized ultraviolet rays selected from polarized ultraviolet rays by a method of passing or reflecting through a Brewster polarizer by reflection or the like. In this case, the polarized ultraviolet rays may be irradiated perpendicularly to the substrate surface, or may be irradiated at an inclined angle at a specific angle. In this way, the alignment capability of the liquid crystal molecules is imparted to the coating film.

In addition, the rubbing treatment in the alignment treatment may use a method using a rubbing cloth. More specifically, the rubbing treatment may rub the surface of the coating film after the heat treatment step in one direction while rotating the rubbing roller having the cloth of rubbing cloth attached to the metal roller.

Step 4 is a step of curing the alignment-treated coating film by heat treatment. In this case, the heat treatment may be performed by a heating means such as a hot plate, a hot air circulation furnace, an infrared furnace, and the like, and may be performed at a temperature of 180 ° C. to 300 ° C., or 200 ° C. to 300 ° C.

III. Liquid crystal display device

Moreover, this invention provides the liquid crystal display element containing the liquid crystal aligning film mentioned above.

The liquid crystal alignment layer may be introduced into the liquid crystal cell by a known method, and the liquid crystal cell may likewise be introduced into the liquid crystal display device by a known method.

Meanwhile, the initial luminance before driving the liquid crystal display may be 0.1 cd / cm ² or less, or 0.01 cd / cm ² to 0.1 cd / cm ² .

The initial luminance L0 measured before driving of the liquid crystal display device is a luminance of a black state by attaching the polarizing plates to the upper and lower plates of the liquid crystal display device so as to be perpendicular to each other, and attaching the polarizing plates to the backlight of 7,000 cd / m 2.

Such a liquid crystal alignment cell having an initial luminance value before low driving can realize excellent alignment characteristics.

Specifically, the liquid crystal display may have a voltage retention of 98% or more, or 99% or more, or 98% to 99.9%, measured using a TOYO Corporation 6254C device at 1V, 1Hz, and 60 ° C. When the voltage retention measured by TOYO Corporation's 6254C equipment is reduced to less than 98% at 1V, 1Hz, and 60 ° C of the liquid crystal alignment display device, it is difficult to implement a liquid crystal display device having high quality driving characteristics at low power. Can lose.

In addition, the liquid crystal display device is a DC stress at 60 ℃, after applying + DC in the range of 0.5 ~ 1V for 1 minute, and after leaving no voltage applied for 2 minutes, the residual DC amount of residual DC is less than 200mV Or 10 mV or less, or 1 mV or less, or 0.1 mV or less, or 0.01 mV or more, or 0.05 mV or more. When the residual DC of the liquid crystal alignment display device is increased to more than 200 mV, it may be difficult to implement a liquid crystal display device having high quality driving characteristics at low power.

According to the present invention, it is possible to increase the yield of the panel through excellent cleaning power, and to provide a liquid crystal alignment layer, a method of manufacturing a liquid crystal alignment layer having improved liquid crystal alignment characteristics and electrical characteristics, and a liquid crystal display device using the same.

The invention is explained in more detail in the following examples. However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited by the following examples.

Preparation Example: Preparation of Diamine

Preparation Example 1

18.3 g (100 mmol) of 2-chloro-5-nitropyridine (Compound 1) and 12.5 g (98.6 mmol) of paraphenylenediamine (p-PDA, Compound 2) were added to 200 mL of dimethyl. After completely dissolved in sulfoxide (Dimethylsulfoxide, DMSO), 23.4 g (200 mmol) of triethylamine (TEA) was added and stirred at room temperature for 12 hours. Upon completion of the reaction, the reaction was placed in a vessel containing 500 mL of water and stirred for 1 hour. The solid obtained by filtration was washed with 200 mL of water and 200 mL of ethanol to synthesize 16 g (61.3 mmol) of Compound 3 (yield: 60%).

The compound 3 was dissolved in a 200 mL solution in which ethyl acetate (EA) and THF were mixed 1: 1, and 0.8 g of palladium (Pd) / carbon (C) was added thereto, followed by stirring for 12 hours in a hydrogen environment. . After completion of the reaction, the filtrate was concentrated in a celite pad to prepare 11 g of compound 4 diamine (N-4-Aminophenyl-2,5-pyridinediamine, p-IDA). (Yield: 89%)

Preparation Example 2

18.3 g (100 mmol) of 2-chloro-5-nitropyridine (compound 5) and 12.5 g (98.6 mmol) of paraphenylenediamine (p-PDA, compound 6) were added to 200 mL of dimethyl. After completely dissolved in sulfoxide (Dimethylsulfoxide, DMSO), 23.4 g (200 mmol) of triethylamine (TEA) was added and stirred at room temperature for 12 hours. Upon completion of the reaction, the reaction was placed in a vessel containing 500 mL of water and stirred for 1 hour. The solid obtained by filtration was washed with 200 mL of water and 200 mL of ethanol to synthesize 16 g (61.3 mmol) of Compound 7. (Yield: 60%)

The compound 7 was dissolved in a 200 mL solution in which ethyl acetate (EA) and THF were mixed 1: 1, and 0.8 g of palladium (Pd) / carbon (C) was added thereto, followed by stirring for 12 hours in a hydrogen environment. . After completion of the reaction, the filtrate was concentrated in a celite pad to prepare 11 g of Compound 8 diamine (yield: 89%).

<Example: Production of liquid crystal aligning agent composition and liquid crystal aligning film>

Example 1

(1) Preparation of liquid crystal aligning agent composition

1.401 g (7 mmol) of diamine (N-4-Aminophenyl-2,5-pyridinediamine) of Preparation Example 1 was dissolved in 15.37 g of anhydrous N-methylpyrrolidone (NMP), followed by ice bath. Pyromellitic dianhydride (Pyromellitic dianhydride (PMDA)) under 1.450 g (6.65 mmol) was added to the solution and stirred at room temperature for 16 hours to prepare polymer P-1 for liquid crystal aligning agent.

20 g of the liquid crystal aligning agent polymer (P-1) was dissolved in a mixed solvent of 8.65 g of NMP, 19.95 g of GBL, and 11.4 g of 2-butoxyethanol to obtain a 5 wt% solution. Then, the obtained solution was filtered under pressure with a filter having a pore size of 0.1 μm of poly (tetrafluoreneethylene) to prepare a liquid crystal aligning agent composition A-1.

 (2) Preparation of Liquid Crystal Alignment Film

Liquid crystal aligning agent composition A obtained in (1) of Example 1 by spin coating on a rectangular glass substrate having a thickness of 60 nm and an area of 1 cm x 1 cm, and having a pattern of 2.5 cm x 2.7 cm -1 was applied. Subsequently, the board | substrate with which the liquid crystal aligning agent composition was apply | coated was put on the 80 degreeC hotplate, and it dried for 2 minutes. Thereafter, the linear polarizer was subjected to alignment treatment by irradiating ultraviolet rays at 254 nm with an exposure dose of 0.25 J / cm 2 using an exposure apparatus, and baking (curing) for 15 minutes in an oven at 230 ° C. to prepare a liquid crystal alignment film having a thickness of 0.1 μm.

Example 2

(1) Preparation of liquid crystal aligning agent composition

1.408 g (7 mmol) of diamine of Preparation Example 2 was dissolved in 15.37 g of anhydrous N-methyl pyrrolidone (NMP), and then pyromellitic dianhydride (PMDA) 1.450 in an ice bath. g (6.65 mmol) was added to the solution, followed by stirring at room temperature for 16 hours to prepare Polymer P-2 for liquid crystal aligning agent.

20 g of the liquid crystal aligning agent polymer (P-2) was dissolved in a mixed solvent of 8.65 g of NMP, 19.95 g of GBL, and 11.4 g of 2-butoxyethanol to obtain a 5 wt% solution. Then, the obtained solution was filtered under pressure with a filter having a pore size of 0.1 μm of poly (tetrafluoreneethylene) to prepare a liquid crystal aligning agent composition A-2.

(2) Preparation of Liquid Crystal Alignment Film

In the same manner as in Example 1, except that the liquid crystal aligning agent composition A-2 obtained in the above-mentioned Example 2 (1) was used instead of the liquid crystal aligning agent composition A-1 obtained in the above Example 1 (1). A liquid crystal aligning film was manufactured.

<Comparative example: Production of a liquid crystal aligning agent composition and a liquid crystal aligning film>

Comparative Example 1

Polymer Q1 for liquid crystal aligning agent, liquid crystal alignment in the same manner as in Example 1 except that 3,5-diaminobenzotrifluoride was used instead of the diamine prepared in Preparation Example 1. The composition B-1 and the liquid crystal aligning film were manufactured.

Comparative Example 2

4,4 '-[1,4-phenylenebis (1-methyl-ethylidene)] bisaniline (4,4'-[1,4-Phenylenebis (1-Methyl-) instead of the diamine prepared in Preparation Example 1 Except for using ethylidene)] bisaniline), the polymer Q-2 for the liquid crystal aligning agent, the liquid crystal aligning agent composition B-2, and the liquid crystal aligning film were manufactured in the same manner as in Example 1.

Comparative Example 3

Except for using 2- (4-aminophenyl) -1H-benzoxazole-5-amine (2- (4-aminophenyl) -1H-benzoxazole-5-amine) instead of the diamine prepared in Preparation Example 1, In the same manner as in Example 1, polymer Q-3 for liquid crystal aligning agent, liquid crystal aligning agent composition B-3 and a liquid crystal aligning film were prepared.

Comparative Example 4

Except for using the 6- (4-aminophenyl) pyridin-3-amine [6- (4-aminophenyl) pyridin-3-amine] represented by the following formula A instead of the diamine prepared in Preparation Example 1 In the same manner as in Example 1, polymer Q-4 for liquid crystal aligning agent, liquid crystal aligning agent composition B-4 and a liquid crystal aligning film were prepared.

Formula A

Comparative Example 5

For liquid crystal aligning agent in the same manner as in Example 1 except for using 4,4'-diaminodiphenylamine [4,4'-diaminodiphenylamine] represented by the following formula B instead of the diamine prepared in Preparation Example 1 Polymer Q-5, liquid crystal aligning agent composition B-5 and a liquid crystal aligning film were prepared.

[Formula B]

<Experimental example: Measurement of physical properties of the liquid crystal aligning agent composition and liquid crystal aligning film obtained by the Example and the comparative example>

The physical properties of the liquid crystal aligning agent composition or liquid crystal aligning film obtained in the above Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1.

1. Evaluation of liquid crystal alignment characteristics

The polarizing plates were attached to the upper and lower plates of the liquid crystal cell manufactured as described above to be perpendicular to each other. At this time, the polarization axis of the polarizing plate attached to the lower plate was to be parallel to the alignment axis of the liquid crystal cell. And the liquid crystal cell with a polarizing plate was attached on the backlight of brightness 7,000cd / m <^2> , the brightness of black state was measured using PR-880 equipment which is a brightness brightness measuring instrument, and the liquid-crystal orientation characteristic was evaluated based on the following reference | standard. .

Excellent: 0.1 cd / cm ² or less

Normal: more than 0.1 cd / cm ²

2. Voltage holding ratio (VHR)

About the said liquid crystal aligning cell, voltage retention was measured at 1V, 1Hz, and 60 degreeC temperature using 6254C equipment of TOYO Corporation as a measuring equipment.

3. RDC evaluation (residual DC voltage, residual DC)

For the liquid crystal aligning cell, after applying DC stress at a temperature of 0.5 to 1 V at + 60 ° C. for 1 minute and leaving no voltage applied for 2 minutes, the amount of remaining DC was measured as residual DC. And it evaluated based on the following criteria.

Excellent: less than 200 mV

Medium: 200 mV to 300 mV

4. Cleaning power

 (1) contact angle measurement

A contact angle (A ₀₎ in the second holding the first point of the Examples and Comparative Examples 1 ㎕ ultrapure water to a liquid crystal alignment film surface is dropped O, O second was measured at a temperature 24 ℃, humidity 22-32% conditions.

Thereafter, while measuring the contact angle in units of 1 second, the contact angle A ₁ after 50 seconds passed from the first time point (0 seconds) when 1 µl of ultrapure water was dropped on the surface of the liquid crystal alignment film was measured.

Moreover, the contact angle (A ₂ ) after 25 second passed from the initial time (0 second) which 1 microliter of ultrapure water was dripped on the liquid crystal aligning film surface was measured.

(2) cleaning power

The first contact angle average change rate in the range of 0 to 50 seconds by the following equation 1, the second average change rate of contact angle in the range of 0 second to 25 seconds by the following equation 2, 50 to 25 seconds by the following equation The average rate of change of the third contact angle in the second section was obtained.

[Equation 1]

Average change rate of contact angle from 0 to 50 seconds (° / sec) = (A ₀ -A ₁ ) / 50

[Equation 2]

2nd contact angle average rate of change (° / sec) = (A ₀ -A ₂ ) / 25

[Equation 3]

3rd contact angle average rate of change (° / sec) = (A ₂ -A ₁ ) / 25

Then, the cleaning power was evaluated under the following criteria.

Good cleaning power: average change rate of the first contact angle according to Equation 1 is 0.035 ° / sec or more

Poor cleaning power: The average change rate of the first contact angle according to Equation 1 is less than 0.035 ° / sec

Experimental Example Measurement Results of Examples and Comparative Examples division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Liquid Crystal Alignment Characteristics Great Great usually usually usually usually usually VHR (%) 99 99 97 96 97 96 97 RDC Great Great usually usually usually usually usually Contact angle A ₀ 56.3 55.9 50.9 52 51.6 51.3 54.8 A ₁ 52.4 52.8 50.1 50.3 50.6 50.3 53.9 A ₂ 53.6 53.5 50.4 50.7 51.0 50.7 54.3 Cleaning power Equation 1 0.078 0.062 0.016 0.034 0.020 0.020 0.018 Equation 2 0.108 0.096 0.020 0.052 0.024 0.024 0.020 Equation 3 0.048 0.028 0.012 0.016 0.016 0.016 0.016

As shown in Table 1, the liquid crystal aligning film of the example obtained by using a polymer synthesized from the diamine of the specific structure obtained in Preparation Example 1 or Preparation Example 2 has a contact angle average change rate of 0.062 ° / sec to 0.078 As high as ° / sec, it was confirmed that the wettability is improved by significantly lowering the contact angle within a short time. On the other hand, using a polymer synthesized using a known diamine instead of the diamine of a specific structure obtained in Preparation Example 1 or Preparation Example 2 In the obtained liquid crystal alignment film of Comparative Example, the average change rate of contact angle according to Equation 1 was 0.016 ° / sec to 0.034 ° / second, which was lower than that of the embodiment, and thus, it was difficult to secure sufficient wettability due to less contact angle reduction during the same time.

Through this, it was confirmed that the liquid crystal alignment layer of the embodiment having a much greater degree of contact angle reduction for the same time can realize an excellent surface cleaning effect during ultrapure water cleaning based on high wettability.

On the other hand, the liquid crystal alignment cell using the liquid crystal alignment film obtained in the above embodiment, it was confirmed that showing the improved liquid crystal alignment characteristics and electrical properties than the comparative example.

Claims (13)

It includes a polymer containing at least one selected from the group consisting of polyimide repeat unit, polyamic acid ester repeat unit, and polyamic acid repeat unit,
The liquid crystal aligning film whose 1st contact angle average change rate by the following formula (1) is 0.035 degrees / sec or more:
[Equation 1]
Average change rate of first contact angle (° / sec) = (A ₀ -A ₁ ) / 50
In Equation 1,
A ₀ is the contact angle of the liquid crystal alignment film at the first time point (0 second) when 1 µl of ultrapure water was dropped on the surface of the liquid crystal alignment film,
A ₁ is the contact angle of the liquid crystal aligning film after 50 second has passed since the initial time (0 second) when 1 microliter of ultrapure water was dripped on the liquid crystal aligning film surface.
The method of claim 1,
The first contact angle average change rate according to Equation 1 is 0.060 ° / sec to 0.080 ° / sec, the liquid crystal alignment film.
The method of claim 1,
In Equation 1, A ₀ is 55 ° to 70 °, the liquid crystal alignment film.
The method of claim 1,
In Equation 1, A ₁ is 50 ° to 55 °, the liquid crystal alignment film.
The method of claim 1,
2. The liquid crystal alignment film of claim 2, wherein the average change rate of the second contact angle according to Equation 2 is equal to or greater than twice the average change rate of the third contact angle according to Equation 3 below:
[Equation 2]
2nd contact angle average rate of change (° / sec) = (A ₀ -A ₂ ) / 25
In Equation 2,
A ₀ is the contact angle of the liquid crystal alignment film at the first time point (0 second) when 1 µl of ultrapure water was dropped on the surface of the liquid crystal alignment film,
A ₂ is the contact angle of the liquid crystal alignment film after 25 seconds from the first time point (0 second) when 1 μl of ultrapure water was dropped on the surface of the liquid crystal alignment film,
[Equation 3]
3rd contact angle average rate of change (° / sec) = (A ₂ -A ₁ ) / 25
In Equation 3,
A ₂ is the contact angle of the liquid crystal alignment film after 25 seconds from the first time point (0 second) when 1 μl of ultrapure water was dropped on the surface of the liquid crystal alignment film,
A ₁ is the contact angle of the liquid crystal aligning film after 50 second has passed since the initial time (0 second) when 1 microliter of ultrapure water was dripped on the liquid crystal aligning film surface.
The method of claim 5,
The second contact angle average change rate according to Equation (2) is 3.3 times or more than the third average change rate of contact angle according to Equation (3).
The method of claim 5,
In the formulas (2) and (3), A ₂ is 51.5 ° to 54 °, the liquid crystal alignment film.
The method of claim 1,
The polyimide repeating unit includes a repeating unit represented by the following Formula 1, and the polyamic acid ester repeating unit includes a repeating unit represented by the following Formula 2, and the polyamic acid repeating unit is a repeating unit represented by the following Formula 3 Liquid crystal aligning film containing:
[Formula 1]

[Formula 2]

[Formula 3]

In Chemical Formulas 1 to 3,
At least one of R ₁ and R ₂ is alkyl having 1 to 10 carbon atoms, the rest are hydrogen,
X ₁ to X ₃ are the same as or different from each other, and each independently a tetravalent organic group,
Y ₁ to Y ₃ are the same as or different from each other, and each independently a divalent organic group represented by the following general formula (4),
[Formula 4]

In Formula 4, at least one of Q ₁ to Q ₈ is nitrogen, the remainder is carbon, D is -NR'- or -O-, and R 'is hydrogen or an alkyl group having 1 to 6 carbon atoms.
The method of claim 8,
A divalent organic group represented by Formula 4 includes a divalent organic group represented by Formula 5 below, or a divalent organic group represented by Formula 6 below:
[Formula 5]

[Formula 6]

.
The method of claim 8,
X ₁ to X ₃ are each independently one of tetravalent organic groups represented by the following formula (6), a liquid crystal alignment film:
[Formula 6]

In Chemical Formula 6,
R ₅ to R ₁₀ are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,
L ₁ is a single bond, -O-, -CO-, -COO-, -S-, -SO-, -SO _2- , -CR ₁₁ R ₁₂ -,-(CH ₂ ) _t- , -O (CH ₂ ) _t O-, -COO (CH ₂ ) _t OCO-, -CONH-, phenylene or any combination thereof
R ₁₁ and R ₁₂ in L ₁ are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a halo alkyl group,
t is an integer from 1 to 10.
The method of claim 1,
The liquid crystal aligning film containing the orientation hardened | cured material of the liquid crystal aligning agent composition containing the polymer containing 1 or more types chosen from the group which consists of a polyimide repeating unit, a polyamic acid ester repeating unit, and a polyamic acid repeating unit.
Forming a coating film by applying a liquid crystal aligning agent composition comprising a polymer including at least one selected from the group consisting of a polyimide repeating unit, a polyamic acid ester repeating unit, and a polyamic acid repeating unit;
Drying the coating film;
Irradiating or rubbing the light on the dried coating layer to perform alignment; And
The liquid crystal aligning film manufacturing method of Claim 1 including the process of hardening by heat-processing the said orientation-treated coating film.
A liquid crystal display device comprising the liquid crystal alignment film of claim 1.