KR20030039099A - Triazine ring based polyurea polymers for photoinduced liquid crystal alignment and liquid crystal alignment layer comprising the same - Google Patents

Abstract

PURPOSE: A liquid crystal aligning agent, a photosensitive polymer liquid crystal alignment layer using the aligning agent, a liquid crystal device using the alignment layer and a preparation method of the alignment layer are provided, to improve the alignment characteristic, the heat stability, the photo stability and the electro-optical property. CONSTITUTION: The liquid crystal aligning agent comprises a polyurea-based photosensitive polymer having the triazine ring represented by the formula I as a main chain, wherein R1 is represented by the formula 1a, 2a, 3a or 4a, m+n=1, 0<=m<=1 and 0<=n<=1. The liquid crystal alignment layer is prepared by coating the liquid crystal aligning agent dissolved in an organic solvent with a concentration of 1-20 wt% and a viscosity of 1-100 cps on a substrate to form an alignment layer with a thickness of 10-500 nm, and irradiating UV to the alignment layer.

Description

Triure ring-based polyurea polymers for photoinduced liquid crystal alignment and liquid crystal alignment layer comprising the same}

The present invention relates to a polyurea-based photosensitive polymer liquid crystal aligning agent having a triazine ring as a main chain and a liquid crystal alignment layer using the same, and in particular, a side chain of a photoactive group which induces liquid crystal alignment in the polymer main chain and enhances, improves and preserves the alignment of the liquid crystal. It relates to a photosensitive polymer liquid crystal aligning agent having one or more photoactive sites introduced therein and a liquid crystal aligning film using the same.

A photosensitive polymer liquid crystal aligning agent is used as a liquid crystal aligning agent of a device using optical properties of a liquid crystal. Generally, a liquid crystal is oriented by applying an alignment agent on a substrate and irradiating ultraviolet light to the surface to form anisotropy on the surface thereof. Combination and its components.

Liquid crystal devices using polymer liquid crystal aligning agents have been used in various fields such as liquid crystal displays, compensators, and optical components. Therefore, the present invention will be mainly described as a display device, but the liquid crystal alignment film according to the present invention is not limited to the display device, and it should be understood that the liquid crystal alignment film of the present invention can be used in various applications of the liquid crystal device described above. do.

The flat panel display device to which the liquid crystal display device is applied is gradually replacing the existing CRT because it is light, thin and large in area. Among these flat panel displays, liquid crystal displays (LCDs), in particular, are leading the flat panel display market because they are easy to carry and consume less power. In addition, this liquid crystal display is expanding its application range from applications such as calculators and notebook computers to wall-mounted televisions and high definition televisions.

In order for the liquid crystal element to implement an image, the liquid crystal must be oriented in a specific direction at the interface between the liquid crystal and the transparent conductive glass such that the liquid crystal is switched by an external electric field between the transparent conductive glass. The degree of alignment of such liquid crystals is the most important factor in determining the superiority of the liquid crystal display image quality.

Conventionally, three representative methods are known as a method of orienting a liquid crystal. As shown in Fig. 1, after coating a polymer compound such as polyimide on a substrate, the surface is coated with nylon, polyester, or rayon. It is a rubbing method in which a fine groove is formed on the surface of a polymer by rubbing a fiber-wrapped cloth with a rubbing drum. The second method is a SiO deposition method for depositing silicon oxide (SiO) on the substrate in an oblique direction, and the third method is a photosensitive film applied by applying a photosensitive polymer liquid crystal aligning agent to the substrate and irradiating the light vertically or obliquely. It is a photo-alignment method in which polymer material causes photoreaction to form anisotropy on the surface.

According to the first method, when rubbing the surface of the polymer compound with a rubbing drum, fine dust is generated or discharge is generated by static electricity, which causes problems in the manufacturing process of the liquid crystal panel. According to the second method, it is difficult to maintain uniformity of the deposition angle and the film thickness with respect to the substrate, and there is a problem that the process also becomes large. Moreover, in the 3rd method, there exists a problem that the physical bonding force between the photosensitive polymer liquid crystal aligning agent with which anisotropy was formed, and a liquid crystal is weak, and an orientation becomes weak by heat, and this method is not practically applied.

Among the conventional methods, the liquid crystal alignment according to the third method was developed to induce photoreaction of the photosensitive polymer by light irradiation to form anisotropy on the coated surface to orient the liquid crystal. Such an alignment method is a non-contact type to the alignment surface. The treatment method is characterized in that no dust, static electricity or other contaminant particles are generated so that cleanness is maintained throughout the entire process. The possibility of photoalignment has been found using azobenzene compounds (K. Ichimura et al., Langmuir, 4, 1214, 1988), followed by polymaleimide (HJChoi et al., US Patent 6218501), Several kinds of high molecular compounds such as polyolefins (RHHerr et al. US Patent 6201087) have been developed as photo-alignment materials.

However, the practical use of the photo-alignment method has to solve problems such as the demand for a large amount of ultraviolet rays along with the improvement of the photochemical stability, thermal stability and electro-optic properties, and the development of a new photo-alignment material is required to solve such problems. It is becoming.

The present invention relates to a non-contact liquid crystal alignment method through light irradiation, which solves the problems of the conventional rubbing method of the liquid crystal alignment method or the silicon oxide deposition method and can align the liquid crystal in a multi domain. It is an object of the present invention to provide new photoalignment materials which exhibit good orientation properties, good thermal stability and light stability, and improved electro-optic properties for liquid crystals.

That is, in the present invention, the triazine derivative is used as the main chain of the polymer, thereby inducing the orientation of the liquid crystal in the polymer main chain and introducing a side chain of the photoactive group which enhances, enhances and preserves the orientation of the liquid crystal. It provides a photosensitive polymer liquid crystal aligning agent having a photoactive group). One of the photoactive sites can undergo Fries rearrangement leading to the orientation of the liquid crystal, while the other sites have photodimerization and photoisomerization for enhancing, correcting and preserving the resulting orientation. photoisomerization or photocrosslinking and photodegradation.

Moreover, another object of this invention is to provide the liquid crystal aligning film using the said photosensitive polymer liquid crystal aligning agent.

Other objects and advantages of the invention will be described below, and will be better understood by practice of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the appended claims.

1 is a side view showing an alignment process of a conventional liquid crystal alignment film,

2 is a perspective view schematically showing an alignment process of a liquid crystal alignment film according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Prior to this, the terms or words used in the present specification and claims are based on the principle that the inventor can appropriately define the concept of terms in order to explain the invention in his best manner, and the technical features of the present invention It should be interpreted as meanings and concepts consistent with ideas, and not limited to ordinary or dictionary meanings.

In addition, the configuration of the embodiments described herein is only one of the most preferred embodiments of the present invention and does not represent all of the technical idea of the present invention, and various equivalents that may be substituted for them at the time of filing the present invention and It should be understood that there may be variations.

The photosensitive polymer liquid crystal aligning agent provided in the present invention includes a polymer having one or more photoactive groups, and the general structure of the polymer is represented by the following Chemical Formula 1.

(m + n = 1, 0 ≤ m ≤ 1 and 0 ≤ n ≤ 1)

In Formula 1, R ₁ is _one of the following Formulas (1a) to (4a).

In the above formula (1a), X is selected from the following formulas.

(Where m and n are each 0 to 10)

In the formula (1a) Y is selected from the following formula,

1,2,3,4,5,6,7,8,9 are each selected from the following formulas.

(Where m and n are each 0 to 10 and A and B are each H, F, Cl, CN, CF ₃ or CH ₃ )

In Formulas (2a) and (3a), n is 0 to 10, and 1,2,3,4,5 are each selected from the following chemical formulas.

(Where m and n are each 0 to 10 and A and B are each H, F, Cl, CN, CF ₃ or CH ₃ )

In the formula (4a), Y is selected from the following chemistries.

(Where n is 0 to 10)

In Formula (4a), 1 and 2 are each one selected from

(Where A is H, F, CH ₃ , CF ₃ or CN)

In Formula 1, R ₂ and R ₃ are each one selected from the following.

(Where m and n are each 0 to 10)

In addition, in Formula 1, R ₄ and R ₅ are each one selected from the following.

Where 1,2,3,4,5,6,7,8 are H, F, Cl, CN, CF ₃ , (CH ₂ ) _n CH ₃ , O (CH ₂ ) _n CH ₃ , and A and B is H, F, Cl, CN, CF ₃ , (CH ₂ ) _n CH ₃ , O (CH ₂ ) _n CH ₃ , and n is 0 to 10)

Formula 1 shows the general structure of the polyurea-based photosensitive polymer of the present invention, which is a urea bond is formed by the reaction of an isocyanate and an amine, and the reaction is shown in Scheme 1 below. Here, the isocyanate may again react with the urea bond to form a non-uret bond, which is shown in Scheme 2 below. Therefore, the polymer of the present invention represented by Formula 1 may have a urea bond and a non-uret bond together. Of course, in the general formula (1) showing the general structure, only urea bonds are shown, but the present invention does not exclude polyurea-based polymers having non-uret bonds.

In addition, the benzene ring included in the photosensitive polymer of Chemical Formula 1 has an ortho- or meta- structure in addition to the para- structure, or ortho-, meta-, para- It may have a mixed structure of.

The polyurea-based photosensitive polymer of the present invention represented by Chemical Formula 1 has one or more photoactive groups, in particular, one of these photoactive sites may undergo photodegradation, and the other is freeze Fries rearrangement may occur, and the remaining sites may be photodimerization, photoisomerization or photocrosslinking to enhance, modify and preserve the resulting orientation. have.

The liquid crystal aligning agent including the photosensitive polymer of the present invention represented by Chemical Formula 1 may be used to prepare a photosensitive polymer liquid crystal alignment layer by applying ultraviolet light after coating on a substrate. In particular, the photosensitive polymer liquid crystal aligning agent of the present invention may change the pretilt angle of the liquid crystal oriented according to the inclination angle of the ultraviolet light to be obliquely irradiated, and adjust the change of the chemical structure or the irradiation angle of the ultraviolet light to zero the pretilt angle. ° can be made.

Therefore, the liquid crystal display (LCD) manufactured by using the photosensitive polymer liquid crystal aligning agent of the present invention is Suered Twisted Nematic (STN), Twisted Nematic (TN), In Plane Switch (IPS), Vertical Alignment (VA), and VATN (Vertically). It can be applied to various modes such as Aligned Twisted Nematic mode.

In addition, the liquid crystal device to which the liquid crystal alignment property is imparted by the liquid crystal alignment film of the present invention can be used in various application fields such as a compensator or an optical component in addition to the liquid crystal display device (LCD) described above.

The liquid crystal aligning agent of the present invention has high quality and high quality display having at least the same or better characteristics than the polyimide polymer liquid crystal aligning agent used in the existing rubbing process with excellent polyurea-based polymer properties and excellent liquid crystal orientation. Can be implemented.

Hereinafter, the method of manufacturing a liquid crystal aligning film using the polyurea type photosensitive polymer liquid crystal aligning agent of this invention is demonstrated in detail.

First step

A liquid crystal aligning agent comprising the photosensitive polymer of the present invention represented by Chemical Formula 1 is dissolved in an organic solvent at a viscosity of 1 to 20 wt% and 1 to 100 cps, and then coated on a substrate with a thickness of 10 to 500 nm to form an alignment layer. .

As the organic solvent, chlorobenzene, N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylimidazolidinone (DMI), N, N-di Propylimidazolidinone (DPI), Dimethylformamide (DMF), Dimethylacetamide (DMAc), Dimethylsulphoxide (DMSO), Cyclopentanone, Cyclohexanone, Dichloroethane, Butylcellusolve, Gammabuti Rolactone (γ-butyrolactone) and tetrahydrofuran (THF) and the like may be used alone or in combination.

The liquid crystal aligning agent dissolved in the organic solvent is coated on a substrate such as an ITO glass substrate with a predetermined thickness in the range of 10 to 500 nm to form a film. In this case, all possible conventional methods such as spin coating and roll printing may be used. Can be.

2nd step

Ultraviolet rays are irradiated onto the surface of the alignment film coated with the liquid crystal aligning agent obtained in the above step to prepare a photosensitive polymer liquid crystal alignment film. In this case, the ultraviolet ray is inclined or vertically irradiated with ultraviolet rays linearly polarized using a polarizer or unpolarized ultraviolet rays not using a polarizer to produce a liquid crystal alignment layer.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples illustrate specific embodiments of the present invention and should not be construed as limiting or limiting the protection scope of the present invention.

Example 1

Polyurea type polymer liquid crystal aligning agent which has cinnamate photosensitive functional group

(1) Modification of Triazine Rings

25.7 g of 4- (2-tetrahydropyranyloxy) bromobenzene was dissolved in 250 mL of dehydrogenated tetrahydrofuran in a nitrogen-filled three-necked flask and reacted with 3 g of magnesium for 24 hours. The solution was reacted at -20 ° C for 12 hours while slowly dropping into a solution in which 18.4 g of cyanuric chloride was dissolved in 200 ml of dehydrogenated tetrahydrofuran in a nitrogen-filled three-necked flask. After the reaction was terminated, the reaction solution was decompressed at room temperature to remove tetrahydrofuran and dissolved in ethyl acetate. The solution was mixed with a basic aqueous solution to extract impurities with vigorous stirring, the aqueous phase was separated and removed, and the ethyl acetate was removed under reduced pressure at room temperature. The solvent was removed and the remaining solid material was recrystallized in n-hexane to give 2- (4- (2-tetrahydropyranyloxy) phenyl) -4,6-dichloro-1,3,5-triazine.

(2) Introduction of hydroxy functional groups to triazine ring

32.6 g of the material obtained in Example 1 (1) was added to a round-bottom flask and dissolved in 300 ml of tetrahydrofuran, followed by adding 0.3 g of pyridinium paratoluenesulfonate, and adding 50 ml of ethanol for 24 hours. Reacted. After completion of the reaction, the solvent was removed by distillation under reduced pressure, and the remaining solids were dissolved in methylene chloride, and then mixed with distilled water in a separatory funnel to extract impurities twice. Calcium chloride was added to the methylene chloride solution to remove moisture, and the solvent was removed by distillation under reduced pressure. This solid phase was recrystallized in a mixed solvent of methylene chloride and normal hexane to give 2- (4-hydroxyphenyl) -4,6-dichloro-1,3,5-triazine.

(3) Synthesis of triazine ring with cinnamate side chain

24.2 g of triazine obtained by the method of Example 1 (2) was placed in a round bottom flask filled with nitrogen, and 200 ml of tetrahydrofuran from which water was removed was dissolved. After 15.2 g of triethylamine was added to the solution and the temperature was lowered to -5 ° C, the diluted cinnamoyl chloride solution was added to 25 g of cinnamoyl chloride and 100 ml of dehydrogenated tetrahydrofuran was added dropwise to the solution. Stirring and reaction were carried out. After completion of the reaction, the reaction solution was distilled under reduced pressure to remove tetrahydrofuran, dissolved in methylene chloride, passed through a filter filled with silica gel, and then distilled under reduced pressure to remove the solvent. Finally, the mixture was recrystallized from a 1: 1 mixed solvent of methylene chloride and normal hexane and filtered under reduced pressure. The obtained solid substance was vacuum dried to obtain triazine having cinnamate side chains.

(4) Synthesis of Triazine Monomer Having Two Amine Functions

37.2 g of triazine obtained by the method of Example 3 (3) was placed in a round bottom flask and dissolved in 400 ml of chloroform. 32.8 g of 4-aminophenol and 12 g of sodium hydroxide were dissolved in 300 ml of distilled water in which 3 g of cetyltrimethylammonium bromide was dissolved, mixed with the previous triazine solution, and reacted vigorously for 24 hours. After completion of the reaction, the organic solution phase was separated, transferred to a separatory funnel, washed three times with distilled water to extract impurities, and then water was removed with calcium chloride. The water-free solution was distilled under reduced pressure to remove chloroform, an organic solvent, and then recrystallized from a mixed solvent of methylene chloride and normal hexane. The precipitated crystals were filtered under reduced pressure and dried in vacuo to obtain a triazine monomer.

(5) Polymerization of polyurea photosensitive polymer liquid crystal aligning agent having cinnamate photosensitive functional group

51.75 g of the triazine monomer obtained by the method of Example 1 (4) was placed in a round bottom flask filled with nitrogen and dissolved in 400 ml of tetrahydrofuran from which water was removed. 17.42 g of toluene diisocyanate was dissolved in 20 mL of tetrahydrofuran from which water was removed, and then reacted for 24 hours while slowly dropwise adding to a triazine monomer solution. After completion of the reaction, the reaction solution was slowly poured into methanol to form a precipitate. The precipitate was dried and then dissolved in 100 ml of dimethyl sulfoxide, and then precipitated in methanol twice. The obtained solid was filtered under reduced pressure and then vacuum dried to prepare a polyurea photosensitive liquid crystal aligning agent having a cinnamate photosensitive functional group.

(6) Fabrication of Liquid Crystal Display Cells

The obtained photo-alignment agent was dissolved in a mixed solvent of NMP and butyl cellussolve at a concentration of 8% by weight, and then the solution was passed through a filtration membrane having a micropore size of 0.1 μm to remove undissolved impurity particles. The solution was printed on a glass substrate coated with a transparent electrode to a thickness of about 300 nm to apply a photoalignment agent, and the glass substrate was dried at about 150 ° C. for about 1 hour to remove the solvent. The glass substrate was used to induce a complex photoreaction such as photopolymerization of cinnamate groups and photolysis of polymer chains through one light irradiation for 2 seconds to 10 seconds at an angle of 20 ° to the ultraviolet light of a 500W mercury lamp. Prepared. A spacer having a size of 4 to 5 μm was sprinkled on the photoreacted two glass substrates, and then attached to the cell gap between 4 and 5 μm using an epoxy adhesive. The cell was subjected to a curing process at 130 ° C. for 1 hour to cure the epoxy adhesive so that the two glass substrates were completely bonded to complete the manufacture of the cell. After injecting liquid crystal into the finished cell and applying heat at 100 to 130 ° C. for 1 hour, a heat treatment step of lowering the temperature to room temperature was performed once to finally obtain a liquid crystal display cell.

Example 2

Polyurea-based photosensitive polymer liquid crystal aligning agent having a chalcone photosensitive functional group

(1) Synthesis of Chalcone Photosensitive Functional Group

10 g of 4-methoxychalcone and 2.05 g of sodium cyanide were dissolved in 100 ml of dimethyl sulfoxide and reacted for 24 hours. After completion of the reaction, the reaction solution was mixed with chloroform and stirred with distilled water to extract impurities. After removing the aqueous phase, chloroform was removed under reduced pressure at room temperature. The remaining solid phase was recrystallized in methanol and then dried in vacuo at 40 ° C. to obtain side chain 4-hydroxychalcone for photoreaction.

(2) Introduction of Chalcone Photosensitive Functional Groups into Triazine Rings

23.8 g of 4-hydroxychalcone synthesized by the method of Example 2 (1) was placed in a round bottom flask filled with nitrogen and dissolved in 240 ml of tetrahydrofuran from which moisture was removed. 2.4 g of sodium hydride (NaH) was added thereto and reacted at room temperature for 6 hours. 18.4 g of cyanuric chloride was added to a round bottom flask, and the solution was dissolved in 200 ml of tetrahydrofuran from which water was removed. The solution was stirred vigorously with slow dropping at -5 占 폚 and allowed to react for 24 hours. After the reaction was completed, distillation under reduced pressure was carried out to remove tetrahydrofuran, and the obtained solid was dissolved in chloroform again. The solution was washed three times with distilled water in a separatory funnel to extract impurities, and then water was removed with calcium chloride. The solution was distilled under reduced pressure again to remove chloroform and recrystallized with a mixed solvent of methylene chloride and normal hexane. The obtained material was filtered under reduced pressure and then vacuum dried to obtain triazine having a chalcone photosensitive functional group.

(3) Synthesis of Triazine Monomer Having Two Amine Functions

38.6 g of triazine having a chalcone photosensitive functional group synthesized in the same manner as in Example 2 (2) was placed in a round bottom flask and dissolved in 400 ml of chloroform. Further, 32.8 g of 4-aminophenol and 12 g of sodium hydroxide were dissolved in 300 ml of distilled water in which 3 g of cetyl trimethylammonium bromide was dissolved, mixed with the previous triazine solution, and reacted vigorously for 24 hours. After completion of the reaction, the organic solution phase was separated, transferred to a separatory funnel, washed three times with distilled water to extract impurities, and then water was removed with calcium chloride. The water-free solution was distilled under reduced pressure to remove chloroform, an organic solvent, and then recrystallized from a mixed solvent of methylene chloride and normal hexane. The precipitated crystals were filtered under reduced pressure and dried in vacuo to obtain a triazine monomer.

(4) Polymerization of polyurea photosensitive polymer liquid crystal aligning agent having a chalcone photosensitive functional group

53.15 g of the triazine monomer obtained by the method of Example 2 (3) was placed in a round bottom flask filled with nitrogen and dissolved in 400 ml of tetrahydrofuran from which water was removed. 17.42 g of toluene diisocyanate was dissolved in 20 mL of tetrahydrofuran from which water was removed, and then reacted for 24 hours while slowly dropping into triazine monomer solution. After completion of the reaction, the reaction solution was slowly poured into methanol to form a precipitate. The precipitate was dried and then dissolved in 100 ml of dimethyl sulfoxide and precipitated in methanol twice. The obtained solid was filtered under reduced pressure and then vacuum dried to prepare a polyurea photosensitive liquid crystal aligning agent having a chalcon photosensitive functional group.

(5) Preparation of liquid crystal display cell

The liquid crystal display cell was produced by the method similar to (6) of Example 1, using the polyurea photosensitive polymer liquid crystal aligning agent obtained in (4) of Example 2.

Example 3

Polyurea-based photosensitive polymer liquid crystal aligning agent having coumarin photosensitive functional group

(1) Introduction of coumarin photosensitive functional group

16.2 g of 7-hydroxycoumarin and 2.4 g of sodium hydride (NaH) were placed in a round-bottomed flask filled with nitrogen, dissolved in 160 mL of tetrahydrofuran from which water was removed, and stirred vigorously for 6 hours. . Into this solution, 18.4 g of cyanuric chloride was poured into a round bottom flask and dissolved in 200 ml of tetrahydrofuran from which water was removed, as in Example 1 (2). The reaction was time. After the reaction was completed, distillation under reduced pressure was carried out to remove tetrahydrofuran, and the obtained solid was dissolved in chloroform again. The solution was washed three times with distilled water in a separatory funnel to extract impurities, and then water was removed with calcium chloride. The solution was distilled under reduced pressure again to remove chloroform and recrystallized with a mixed solvent of methylene chloride and normal hexane. The obtained material was filtered under reduced pressure and then vacuum dried to obtain triazine having a coumarin photosensitive functional group.

(2) Synthesis of Triazine Monomer Having Two Amine Functions

31.1 g of a triazine having a coumarin photosensitive functional group synthesized in the same manner as in Example (1) was put in a round bottom flask and dissolved in 400 ml of chloroform. Further, 32.8 g of 4-aminophenol and 12 g of sodium hydroxide were dissolved in 300 ml of distilled water in which 3 g of cetyl trimethylammonium bromide was dissolved, mixed with the previous triazine solution, and reacted vigorously for 24 hours. After completion of the reaction, the organic solution phase was separated, transferred to a separatory funnel, washed three times with distilled water to extract impurities, and then water was removed with calcium chloride. The water-removed solution was distilled under reduced pressure to remove chloroform, an organic solvent, and then recrystallized from a mixed solvent of methylene chloride and normal hexane. The precipitated crystals were filtered under reduced pressure and dried in vacuo to obtain a triazine monomer.

(3) Polymerization of polyurea photosensitive polymer liquid crystal aligning agent having coumarin photosensitive functional group

45.54 g of the triazine monomer obtained by the method of Example 3 (2) was placed in a round bottom flask filled with nitrogen and dissolved in 400 ml of tetrahydrofuran from which water was removed. After dissolving 17.42 g of toluene diisocyanate in 20 mL of tetrahydrofuran from which water was removed, it was reacted for 24 hours while slowly dropping into triazine monomer solution. After completion of the reaction, the reaction solution was slowly poured into methanol to form a precipitate. The precipitate was dried and then dissolved in 100 ml of dimethyl sulfoxide and precipitated in methanol twice. The obtained solid was filtered under reduced pressure, and then vacuum dried to prepare a polyurea photosensitive liquid crystal aligning agent having a coumarin photosensitive functional group.

(4) Preparation of liquid crystal display cell

The liquid crystal display cell was produced by the method similar to (6) of Example 1, using the polyurea photosensitive polymer liquid crystal aligning agent obtained in (3) of Example 3.

Test Example: Measurement of Characteristics of Liquid Crystal Display Cell

The electro-optical properties, thermal stability, light stability, residual DC and VHR characteristics of the liquid crystal display cells prepared in Examples 1 to 3 were measured and the results are shown in Tables 1, 2, 3, and 4 below.

Test Example 1 Change of the Pretilt Angle According to Heat Treatment

As can be seen through Table 1, the photosensitive polymer liquid crystal aligning agent of the present invention has thermal stability, optical transparency, and excellent coating properties, which are basic characteristics of polyimide, which is used in the prior art, and excellent polyurea-based polymer Has characteristics. Therefore, when the photo-aligned liquid crystal cell is manufactured using the polymer liquid crystal aligning agent of the present invention, the multi-domain liquid crystal alignment can be obtained by a simple process, and the pretilt angle of the liquid crystal is maintained even after the high temperature process of the silbaking. Due to its characteristics, it can be applied to a liquid crystal display device requiring high image quality and a wide viewing angle.

division Example 1 Example 2 Example 3 fair Light irradiation Light irradiation Light irradiation Concentration 8 wt% 8 wt% 8 wt% Pretilt Room temperature 0 to 5 ° 0 to 5 ° 0 to 5 ° After heat treatment 0 to 5 ° 0 to 5 ° 0 to 5 ° Contrast 195 190 190

Note) 1. The pretilt angle was measured by the crystal angle rotation method.

2. Heat treatment was performed for 3 minutes at 150 ° C, the baking temperature.

Test Example 2: Thermal Stability

The thermal stability of the liquid crystal cell was evaluated by the following method. After measuring the initial pretilt time of the liquid crystal cell, the change of the pretilt angle with time was measured at room temperature while thermally aging at 150 ° C. When the thermal stability of the orientation was unstable, the pretilt angle changed with time, and when stable, there was almost no change. Table 2 shows the results. As can be seen from Table 2 below, the photoalignment agent of the present invention has excellent thermal stability in which the alignment and pretilt angles of the liquid crystals are stably maintained even in a long time thermal aging state, thereby satisfying basic characteristics for application to a liquid crystal display device. Let's do it.

division Example 1 Example 2 Example 3 Pretilt ～ 5 ° ～ 5 ° ～ 5 ° Thermal aging temperature 150 ℃ 150 ℃ 150 ℃ Heat aging time 48 hours 48 hours 48 hours Pretilt variation none none none

Test Example 3: Light Stability

According to the liquid crystal cell manufacturing method of Examples 1, 2, and 3, the liquid crystal cell for photostability measurement was manufactured, and light stability was measured. In the light stability measurement, the alignment surface of one liquid crystal cell was irradiated with ultraviolet and visible light for 110 minutes, and then the change of alignment characteristics of the irradiation surface and the non-irradiation surface of the liquid crystal cell were visually confirmed. The results are shown in Table 3 below. In general, liquid crystal cells without light stability induce a change in the liquid crystal alignment of the light irradiation surface by the irradiated light and thus change the alignment characteristics of the liquid crystal. Because it is mixed with, it can not be used as a display element.

division Example 1 Example 2 Example 3 Light irradiation 0.5J / ㎠ No change No change No change 1J / ㎠ No change No change No change 2J / ㎠ No change No change No change Wide angle 90 ° No change No change No change 80 ° No change No change No change 70 ° No change No change No change

Test Example 4 Measurement of Residual DC and Voltage Holding Ratio (VHR)

Residual DC was applied to both ends of the liquid crystal cell while varying the DC voltage between -10 V and 10 V. At this time, a capacitance value was measured to obtain residual DC from the magnitude of the hysteresis value. The liquid crystal cell used in the experiment was prepared by the manufacturing method of Examples 1 to 3 described above as samples having a TN structure having a thickness of 4 to 6 μm. Two electrodes of the prepared liquid crystal cell were connected to an LCD meter (Fluke 6306), and the change of capacitance at 1 kHz was recorded while changing the DC power such as 10 V, 0 V, and -10 V. The hysteresis of the capacitance change with respect to voltage was obtained and the residual DC was measured therefrom. Voltage holding ratio (VHR) was measured by applying a pulse having a width of 64 μs at a cycle of 1 Volt and 60 Hz to measure the rate at which the initially applied voltage was maintained within one cycle, and the results are shown in Table 4 below. As shown in Table 4, low residual DCs of 10 to 13 mV were measured at 20 ° C. in all three cases, and VHR was also high as 98 to 99%. This indicates that the photo-alignment agent of the present invention satisfies basic characteristics for use as a liquid crystal display device.

division Example 1 Example 2 Example 3 R-DC 20 ℃ 15 mV 19 mV 18 mV 60 ℃ 38 mV 36 mV 37 mV VHR 20 ℃ 99% 99% 98% 60 ℃ 98% 96% 97%

The present invention provides a photopolymerization and photodegradable polyurea-based photosensitive polymer liquid crystal aligning agent in which photoreactors such as cinnamate-based, coumarin-based, chalcone-based, maleimide-based, etc. are introduced using a triazine derivative as a polymer main chain, By using this as an alignment layer, low thermal stability, which is a problem of existing optical alignment agents having a hydrocarbon-based polymer such as polyvinyl cinnamate, polymaleimide and polyolefin as a main chain, and low alignment force due to weak physical bonding force between the liquid crystal and the alignment layer And it can overcome the problems affected by the light stability in the cell manufacturing process, and has the characteristics such as high mechanical properties, heat resistance, and optical transparency, chemical resistance, etc. that the polyurea-based polymer has Liquid Crystal Display Devices Fabricated Using Polyurea Photosensitive Polymer Liquid Crystal Alignment Agent It is possible to implement a high-quality and high-definition image quality of the display.

Modifications or variations of the present invention can be easily carried out by those skilled in the art, all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (9)

The liquid crystal aligning agent containing the polyurea-type photosensitive polymer which has a triazine ring as a principal chain represented by following General formula (I). Formula (I) (m + n = 1, 0 ≤ m ≤ 1 and 0 ≤ n ≤ 1) In Formula (I), R ₁ is _one of the following Formulas (1a) to (4a), In formula (1a), X is one selected from (Where m and n are each 0 to 10) In Formula (1a), Y is one selected from In the above, 1,2,3,4,5,6,7,8,9 are each one selected from (Where m and n are each 0 to 10 and A and B are each H, F, Cl, CN, CF ₃ or CH ₃ ) In formulas (2a) and (3a), n is 0 to 10, and 1,2,3,4,5 are each one selected from (Where m and n are each 0 to 10 and A and B are each H, F, Cl, CN, CF ₃ or CH ₃ ) In formula (4a), Y is one selected from (Where n is 0 to 10) In Formula (4a), 1 and 2 are each one selected from (Where A is H, F, CH ₃ , CF ₃ or CN) In Formula (I), R ₂ and R ₃ are each one selected from (Where m and n are each 0 to 10) In the formula (I), R ₄ and R ₅ are each one selected from the following. Where 1,2,3,4,5,6,7,8 are H, F, Cl, CN, CF ₃ , (CH ₂ ) _n CH ₃ , O (CH ₂ ) _n CH ₃ , and A and B is H, F, Cl, CN, CF ₃ , (CH ₂ ) _n CH ₃ , O (CH ₂ ) _n CH ₃ , and n is 0 to 10) The method of claim 1, The photosensitive polymer is formed by reacting an isocyanate with an amine to form a urea bond as shown in the following Reaction Formula (II), and the urea bond is reacted with an isocyanate to form a non-uret bond as shown in the following Reaction Formula (III), A liquid crystal aligning agent having a non-yulet bond together. Scheme (II) Scheme (III) The method of claim 1, The benzene ring contained in the photosensitive polymer of Formula (I) has an ortho- or meta- structure or a mixed structure of ortho-, meta- and para-. The photosensitive polymer liquid crystal aligning film manufactured by irradiating an ultraviolet-ray after apply | coating the liquid crystal aligning agent of Claim 1 on a board | substrate to form an oriented film. The liquid crystal element which applied the liquid crystal aligning film of Claim 4, and provided orientation to a liquid crystal. The method of claim 5, The liquid crystal device is used in one of a liquid crystal display (liquid crystal display), a compensator (compensator), an optical component. The method of claim 6, The liquid crystal display (LCD) has one of driving modes such as Suer Twisted Nematic (STN), Twisted Nematic (TN), In Plane Switch (IPS), Vertical Alignment (VA), and Vertically Aligned Twisted Nematic (VATN). Liquid crystal element made into. Dissolving the liquid crystal aligning agent of claim 1 in an organic solvent at a viscosity of 1 to 20 wt% and 1 to 100 cps, and coating the substrate with a thickness of 10 to 500 nm to form an alignment film; A method of manufacturing a photosensitive polymer liquid crystal alignment film, the method comprising: obliquely or vertically irradiating ultraviolet rays linearly polarized using a polarizer or non-polarized ultraviolet rays not using a polarizer. The method of claim 8, The organic solvent is chlorobenzene, N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylimidazolidinone (DMI), N, N-dipropyl Midazolidinone (DPI), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), cyclopentanone, cyclohexanone, dichloroethane, butylcellusolve, gamma butyrolactone (γ-butyrolactone), tetrahydrofuran (THF) and a mixture thereof.