KR100516157B1 - Triazine ring with one more photoactive groups based polyester polymers composition for photoinduced liquid crystal alignment, preparation method of the film for photoinduced liquid crystal thereby and the liguid crystal cell comprising the film - Google Patents

Abstract

Disclosed is a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group, a method of manufacturing the photosensitive polymer liquid crystal aligning film (1) using the same, and a liquid crystal device including the liquid crystal aligning film (1). do. According to the present invention, low thermal stability, which is a problem of conventional optical alignment agents, in particular, hydrocarbon based optical alignment agents, low alignment force due to weak physical bonding force between the liquid crystal and the alignment layer (1), and photo stability in the cell manufacturing process are affected. It can overcome the problem to be received, and at the same time has a high mechanical properties, heat resistance, optical transparency and chemical resistance which is a characteristic of the polyester polymer. As a result, the liquid crystal display according to the present invention can realize high quality and high quality display quality.

Description

Polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group, a method of preparing a photosensitive polymer liquid crystal aligning film using the same and a liquid crystal device comprising the liquid crystal aligning layer TECHNICAL FIELDS BASED POLYESTER POLYMERS COMPOSITION FOR PHOTOINDUCED LIQUID CRYSTAL ALIGNMENT, PREPARATION METHOD OF THE FILM FOR PHOTOINDUCED LIQUID CRYSTAL THEREBY AND THE LIGUID CRYSTAL CELL COMPRISING THE FILM}

The present invention relates to a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group, a method for producing a photosensitive polymer liquid crystal aligning film using the same, and a liquid crystal device including the liquid crystal aligning film.

In the present specification, the photosensitive polymer liquid crystal aligning agent is used as a liquid crystal aligning agent of a device using the optical properties of the liquid crystal. Generally, the liquid crystal is formed by applying an alignment agent on the substrate 2 and irradiating ultraviolet light to the surface to form anisotropy on the surface. It means a combination of a material orienting materials and constituent materials thereof. The liquid crystal device using the photosensitive polymer liquid crystal aligning agent has various application fields such as a liquid crystal display (LCD), a compensator, and an optical part. It is not limited to this.

Liquid crystal display (LCD) is leading the flat panel display market because it has the advantages of easy portability and low power consumption, and it has been expanded to include wall-mounted TVs and high-definition TVs. Tue and wide viewing angles are required.

Such a liquid crystal display device is generally filled with liquid crystals oriented between two glass substrates 2 coated with an alignment layer 1, and rearrangement (switching) of liquid crystal molecules is performed by an electric field applied from the outside. Use what happens to form the desired image. In this case, in order to obtain uniform brightness and high contrast ratio, it is essential to orient the liquid crystal uniformly in a specific direction, and the degree of uniformity of this alignment is determined by the anchoring energy of the alignment layer 1. .

As a method of orienting liquid crystals, techniques such as a silicon oxide gradient deposition method and a photo-alignment method are known as a rubbing process and a non-rubbing process.

1 is a schematic view showing an alignment step of a liquid crystal alignment film by a conventional rubbing method. The rubbing method of inducing orientation by using a rubbing technique to heat-resistant polymers such as polyimide, which are most widely used as an alignment layer, is to print a polymer compound such as polyimide on the substrate 2 as shown in FIG. The method is applied by a method or the like, and the surface is rotated at high speed with a rubbing drum (3) in which nylon, polyester, and rayon fibers are woven, and rubbed to form a very fine groove on the surface of the polymer. While the rubbing process, the liquid crystal molecules are aligned with a constant pretilt angle (θ) on the surface of the alignment agent. This rubbing method is widely used industrially due to its simple process, large area, and high speed treatment.

However, since the shape of the microgrooves formed in the alignment layer 1 varies according to the friction strength between the alignment cloth and the alignment layer, the arrangement of liquid crystal molecules becomes nonuniform, resulting in phase distortion and light scattering. In addition, there is a problem in that the production yield is lowered due to damage of the substrate 2 due to electrostatic discharge (ESD) generated by rubbing the polymer surface and fine dust generated in the rubbing drum 3. In addition, as one of the methods for achieving a wide viewing angle, an alignment film is coated to make a multi-domain display that widens the viewing angle by dividing one pixel into small pixels so that the liquid crystal alignment state of each divided pixel is changed. Complex lithographic processes such as rubbing, coating of photoresist, exposure and development, rubbing, removal of photoresist and the like are required and are undesirable in terms of productivity.

As the non-rubbing method, the silicon oxide oblique deposition method is a method of depositing silicon oxide obliquely with respect to the substrate 2, and it is difficult to maintain uniformity of deposition angle and film thickness with respect to the substrate 2, There is a problem that the process is large.

As a non-rubbing method, the photo-alignment method inclines or vertically irradiates linearly polarized ultraviolet rays 4 or the like onto a substrate 2 coated with a photosensitive polymer, thereby allowing photo-dimerization or photoisomerization. isomerization) and a non-contact treatment of an oriented surface that results in anisotropy on the surface. The possibility of this photoalignment method was discovered using azobenzene compounds, and then various polymer compounds such as polymaleimide and polyolefin were developed as photoalignment materials.

Polymers mainly used up to now include, for example, a photosensitive ethene group, and chalcone, cinnamoyl, coumarin and the like are typical photosensitive portions. The orientation direction has a constant direction with respect to the polarization direction of the linearly polarized ultraviolet light 4, which is determined by the structure of the photosensitive polymer used. In addition, the pretilt direction varies with the incident direction of the irradiated ultraviolet light 4, and the pretilt angle varies with the incident angle and the irradiation energy.

Since the photo-alignment method is a non-contact method, problems due to the introduction of impurities and the generation of static electricity can be basically excluded, so that the cleanness is maintained and the alignment treatment is easy, improving the yield and suitable for mass production. In addition, since the multi-domain can be formed by a relatively simple process of irradiating the ultraviolet light 4 with different polarization directions depending on the region, it is an advantageous method for improving the viewing angle.

However, the conventional photo-alignment method does not uniformly align the liquid crystal due to the low photosensitivity of the photo-alignment material and its weak anisotropy, so that a long irradiation time is required to solve this problem, thereby degrading fairness. In addition, the physical bonding force between the photosensitive polymer liquid crystal aligning agent and the liquid crystal in which the anisotropy is formed is weak, unstable to light, and weak in orientation due to heat.

For example, a conventional photoalignment agent using a polyvinyl alcohol hydrocarbon polymer as a main chain has a low thermal stability, and an alignment force, which is a physical bonding force between the alignment layer 1 and the liquid crystal, is also lower than that of a conventional polyimide alignment agent. Has the disadvantage of falling. In addition, the polymaleimide or polyimide photo-alignment agent proposed in the existing Korean Patent Registration No. 1998-0028532 still has a limitation that the hydrocarbon-based main chain.

Therefore, for the practical use of the photo-alignment method has been required to solve the problem that the improvement of photochemical and thermal stability, the improvement of electro-optic properties and the amount of ultraviolet light is required.

The present invention has been made to solve the above problems,

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group, which is a photoalignment material having excellent photochemical and thermal stability, good electro-optic properties, and good alignment properties for liquid crystals. To provide.

Another object of the present invention is to provide a method for producing a liquid crystal alignment film 1 using the photosensitive polymer liquid crystal aligning agent composition.

Still another object of the present invention is to provide a liquid crystal element comprising the liquid crystal alignment film 1.

In order to achieve the above object,

The present invention consists of a structure of the following [Formula 1] having at least one photoactive group in the side chain and a triazine ring as a main chain,

[Formula 1]

One of the photoactive groups may undergo photolysis, the other may undergo a free fleece shift, and the remaining sites have one or more photoactive groups that may undergo photodimerization, photoisomerization, or photocrosslinking. Provided is a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring.

In order to achieve the other object as described above,

Dissolving a polyester-based photosensitive polymer liquid crystal aligning agent composition using the triazine ring having at least one photoactive group in an organic solvent, and applying the solution onto the substrate 2 by spin coating or printing to form an alignment layer (1). ) And a step of irradiating or vertically irradiating the ultraviolet (4) linearly polarized using a polarizer on the surface of the alignment layer (1) or the unpolarized ultraviolet (4) without using the polarizer. The manufacturing method of the liquid crystal aligning film 1 is provided.

In addition, the ultraviolet irradiation step preferably further comprises the step of forming a multi-domain using a photomask.

In order to achieve another object as described above,

Provided is a liquid crystal device including a liquid crystal aligning film (1) and a substrate (2) using a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group.

Hereinafter, a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group according to the present invention, a method of manufacturing the photosensitive polymer liquid crystal aligning film 1 using the same, and a liquid crystal device including the liquid crystal aligning film 1 This will be described in detail.

Polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group according to the present invention has a structure of the formula [1] having at least one photoactive group in the side chain and a triazine ring as a main chain ,

[Formula 1]

One of the photoactive groups can undergo photolysis, the other can undergo a free fleece shift, and the remaining sites can be photodimerized, photoisomerized or photocrosslinked to enhance, modify and preserve the resulting orientation. Can get angry.

Preferably, R ₁ of [Formula 1] is any _one of the following formulas (1a), (2a), (3a) and (4a),

(The benzene ring may be ortho-, meta-, or a mixture of two or more of the ortho-, meta-, and para-structures in addition to the para-structure.)

In Formula (1a), X is any one selected from the following formulas,

Wherein m and n are each 0 to 10, and the benzene ring may be an ortho- or meta-structure in addition to the para-structure, or a mixed structure of two or more of the ortho-, meta-, and para-structures. It may have been done.)

Y in the formula (1a) is any one selected from the following formula,

(The benzene ring may be ortho-, meta-, or a mixture of two or more of the ortho-, meta-, and para-structures in addition to the para-structure.)

In the above formula, 1, 2, 3, 4, 5, 6, 7, 8, 9 are each selected from the following formula,

(Wherein m and n are 0 to 10, A and B are H, F, Cl, CN, CF ₃ or CH ₃ , and the benzene ring may be ortho- or meta-structure besides para-structure) Or a mixture of two or more of ortho-, meta-, and para-structures.)

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

(Wherein m and n are 0 to 10, A and B are H, F, Cl, CN, CF ₃ or CH ₃ , and the benzene ring may be ortho- or meta-structure besides para-structure) Or a mixture of two or more of ortho-, meta-, and para-structures.)

In the formula (4a) Y is any one selected from the following formula,

(In the above formula, n is 0 to 10, and the benzene ring may be ortho- or meta-structure other than para-structure, or may be a mixture of two or more of ortho-, meta- and para-structures. have.)

In the formula (4a), 1 and 2 are each selected from the following formula.

(Wherein A is H, F, CH ₃ , CF ₃ , CN)

Also preferably, the ester bonds in which R ₂ and R ₃ in Formula 1 are connected to R ₄ or R ₅ , respectively, are obtained in a reaction between diol and carboxylic acid, and the reaction scheme is as follows.

[Scheme 1]

R <_2> and R < ₃ > originate in the alcohol of the said [Reaction Scheme 1], and are each obtained from any one chosen from following Formula.

Wherein m and n are each 0 to 10, and A and 1, 2, 3, 4, 5, 6, 7, and 8 are H, F, Cl, CN, CF ₃ or CH ₃ , and the benzene ring In addition to the para-structure, it may be an ortho-structure, meta-structure, or a mixture of two or more of the ortho-, meta-, and para-structures.)

Preferably, R ₄ and R ₅ of [Formula 1] are derived from the carboxylic acid of [Scheme 1], each one selected from the following.

Wherein m and n are each 0 to 10, and the benzene ring may be an ortho- or meta-structure other than a para-structure, or a mixed structure of two or more of ortho-, meta-, and para-structures. It may have been done.)

2 is a schematic view showing an irradiation step in the alignment process of the liquid crystal aligning film 1 using the photosensitive polymer liquid crystal aligning agent composition according to the present invention.

The method for preparing a liquid crystal aligning film (1) using a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having one or more photoactive groups according to the present invention is described below. The ester photosensitive polymer liquid crystal aligning agent composition was selected from chlorobenzene, N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylimidazolidinone (DMI), and N, N-di Propylimidazolidinone (DPI), Dimethylformamide (DMF), Dimethylacetamide (DMAc), Dimethylsulfoxide (DMSO), Cyclopentanone, Cyclohexanone, Dichloroethane, Butylcellulose, and Gammabutyrolactone and It is dissolved in an organic solvent consisting of any one or at least any two or more mixed solvents selected from the group consisting of tetrahydrofuran (THF) at a concentration of 1 to 20 wt% to make a viscosity of 1 to 1000 cps.

The concentration of the solvent depends on the molecular weight and less than 1 wt% and more than 20 wt% does not yield the desired viscosity and thickness.

If the viscosity is less than 1 cps and more than 1000 cps, the desired thickness cannot be obtained.

Next, the solution is applied onto the substrate 2, for example, an ITO glass substrate 2, by a thickness of 10 to 200 nm by spin coating or printing to form an alignment layer 1.

If it is less than 10 nm and exceeds 200 nm, it is difficult to be applied to the liquid crystal device.

The surface of the alignment layer 1 is inclined or vertically irradiated with ultraviolet rays 4 linearly polarized using a polarizer or unpolarized ultraviolet rays 4 without polarizers for 2 seconds to 10 minutes, and then onto the substrate 2. The liquid crystal aligning film 1 is manufactured in this.

At this time, preferably in the ultraviolet irradiation process using a photomask (photomask) to form a multi-domain.

The irradiation time depends on the power of the lamp. The larger the power, the shorter the irradiation time. The smaller the power, the larger the irradiation time. For lamps of approximately 20 mW, incline or level for 2 seconds to 10 minutes. If less than 2 seconds or more than 10 minutes, the desired orientation may not be obtained.

The polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having one or more photoactive groups according to the present invention may change the pretilt angle of the liquid crystal oriented according to the inclination angle of the ultraviolet ray 4 which is inclinedly irradiated, and the chemical By changing the structure or by operating the ultraviolet ray 4, the pretilt angle can be set to 0 degrees. Therefore, a driving mode of a liquid crystal display device manufactured using a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group according to the present invention is STN (Super Twisted Nematic), TN (Twisted Nematic), It can be applied to various modes such as IPS (In Plane Switching) and VATN (Vertically Alligned Twisted Nematic) mode.

A liquid crystal device comprising a liquid crystal aligning film (1) using a polyester-based photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group according to the present invention is a liquid crystal aligning film prepared on the substrate (2) as described above. Liquid crystal orientation is provided by (1).

The manufacturing method of a liquid crystal display element among such liquid crystal elements is as follows.

After spraying a spacer having a predetermined size on the two photoreacted substrates (2) having a liquid crystal alignment film (1) prepared as described above, by attaching the adhesive between the two substrates (2) to have a constant thickness between the two The cell is subjected to a curing process at about 130 ° C. for 1 hour and then the adhesive is cured so that the two substrates are completely adhered to prepare a cell. Thereafter, a liquid crystal is injected into the cell, heat is applied at 100 to 130 ° C. for about 1 hour, and then a heat treatment step of dropping the temperature to room temperature is performed once. The heat treatment is to crystallize the liquid crystal is heated to more than 100 ℃ crystallized and heated to 130 ℃ clearing temperature (clearing temperature).

Hereinafter, the present invention will be described in more detail by explaining preferred embodiments of the present invention. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only common to those skilled in the art to complete the present disclosure. It is intended to facilitate the implementation of the invention to those with knowledge.

Example 1

Embodiment 1 relates to a polyester-based photosensitive polymer liquid crystal aligning agent having a cinnamate photosensitive functional group, a liquid crystal alignment film production method using the same, and a liquid crystal display device manufacturing method including the liquid crystal alignment film.

(1) Introduction of alcohol functional group

90 g of 4- (2-tetrahydropyranyloxy) bromobenzene was dissolved in a three-necked flask filled with nitrogen with 500 ml of tetrahydrofuran, and then reacted with 9.6 g of magnesium for 3 hours. 18.4 g of cyanuric chloride was added dropwise to a solution in which 200 ml of tetrahydrofuran was dissolved, and the reaction was carried out at a temperature where the solvent was refluxed for about 6 hours. After the reaction was completed, 3 g of pyraninium paratoluenesulfonate was added to the reaction solution, and the reaction was further performed for 6 hours. After completion of the reaction, the reaction mixture 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, after recrystallization in 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 2, 4, 6-trihydroxyphenyl-1,3,5-triazine.

(2) Synthesis of Diol Monomer Having Cinnamoyl Functional Group

14.8 g of cinnamic acid was placed in a round bottom flask filled with nitrogen, and 17.8 g of thionyl chloride (SOCl ₂ ) was added thereto and stirred. Then, 0.5 ml of dimethylformamide (DMF) was further added to the flask, followed by reaction at room temperature for 24 hours. After the reaction was completed, distillation under reduced pressure was carried out to obtain 16 g of cinnamoyl chloride. 35.7 g of the 2, 4, 6-trihydroxyphenyl-1,3,5-triazine was added to a round bottom flask and dissolved in 400 ml of chloroform. 15.2 g of triethylamine was added to the solution, and the temperature was lowered to -5 ° C. Then, 16 g of cinnamoyl chloride obtained above was added dropwise to 20 ml of tetrahydrofuran from which water was removed, followed by vigorous dropping of the diluted cinnamic chloride solution. When stirred, the reaction was 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, after recrystallization in 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 a diol monomer having a cinnamoyl functional group.

(3) Polymerization of polyester photosensitive polymer liquid crystal aligning agent having cinnamate photosensitive functional group

48.7 g of the triazine monomer obtained by the method of (2) was put in a round bottom flask filled with nitrogen and dissolved in 400 ml of tetrahydrofuran from which water was removed. 20.238 g of triethylamine is added to this solution. After dissolving 20.3 g of terephthaloyl chloride in 100 ml of tetrahydrofuran from which water was removed, the mixture was stirred vigorously while slowly dropping into the solution containing the triazine monomer and triethylamine, and reacted for 12 hours. After completion of the reaction, the reaction solution was slowly poured into methanol, precipitated, and filtered. The precipitate was dried in vacuo. The obtained precipitate was again dissolved in tetrahydrofuran and then precipitated in methanol twice, and then vacuum-dried to finally form a polyester polymer liquid crystal having a cinnamate photosensitive functional group using a triazine ring according to this embodiment. The agent was synthesized.

(4) Fabrication of liquid crystal display elements

The obtained photo-alignment agent was dissolved in a mixed solvent of NMP and butyl cellussolve at a concentration of 8 wt%, and then passed through a solution having a micropore size of 0.1 μm to remove undissolved impurity particles. The solution is printed on a glass substrate 2 coated with a transparent electrode to a thickness of 50 to 500 nm to apply a photoalignment agent, and the glass substrate 2 is dried at 150 to 250 ° C. for about 1 to 2 hours to remove the solvent. It was. This glass substrate 2 is used to induce a complex photoreaction such as photopolymerization of cinnamate group and photodegradation of polymer chain through one light irradiation for 2 seconds to 10 minutes at an angle of 20 ° with respect to ultraviolet rays 4 of 500W mercury lamp. To prepare a polymer liquid crystal alignment film. The cell gap between the photoreacted two glass substrates 2 was attached to be 4-5 μm. The cell was cured for one hour at 130 ° C. to cure the epoxy adhesive so that the two glass substrates 2 were completely adhered to complete the manufacture of the cell. After injecting the liquid crystal into the finished cell was heated for 1 hour at 100 ~ 130 ℃ and then the heat treatment step of dropping the temperature back to room temperature was performed once. The electro-optical properties, thermal stability, light stability, residual DC and VHR characteristics of the liquid crystal cell after the heat treatment were measured, and the results are shown in Tables 1, 2, 3, and 4.

Example 2

Embodiment 2 relates to a polyester-based photosensitive liquid crystal aligning agent having a chalcone photosensitive functional group, a method of manufacturing a liquid crystal alignment layer 1 using the same, and a method of manufacturing a liquid crystal display device including the liquid crystal alignment layer 1.

(1) Synthesis of chalcone photosensitive functional groups

10 g of 4-methoxychalcone and 2.05 g of sodium cyanide were dissolved in 100 ml of dimethylsulfoxide 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 group in triazine ring

23.8 g of the synthesized 4-hydroxychalcone is placed in a round bottom flask filled with nitrogen and dissolved in 240 ml of dehydrogenated tetrahydrofuran. 2.4 g of sodium hydride (NaH) was added thereto and allowed to react for 6 hours at room temperature. 18.4 g of triazine was added to a round bottom flask, and the solution was dissolved in 200 ml of tetrahydrofuran from which moisture was removed. The solution was reacted vigorously with vigorous stirring at −5 ° C. for 24 hours. After the reaction was terminated, distillation under reduced pressure was carried out to remove tetrahydrfuran, 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 Diol Functional Group

51.4 g of 4- (2-tetrahydropyranyloxy) bromobenzene was dissolved in 300 ml of water-removed tetrahydrofuran and reacted with 7.2 g of magnesium for 6 hours under nitrogen. In this solution, 38.6 g of the triazine having the synthesized chalcone photosensitive functional group was dissolved in 300 ml of tetrahydrofuran from which water was removed, and then reacted with the Grignard reagent solution prepared above at room temperature for 12 hours. After terminating the reaction, 3 g of pyridinium paratoluenesulfonate was added to the reaction solution, and the reaction was further performed for 6 hours. Finally, 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, after recrystallization in 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 a monomer having a diol functional group.

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

50.1 g of the triazine monomer is placed in a round bottom flask filled with nitrogen and dissolved in 500 ml of tetrahydrofuran from which water is removed. 20.2 g of triethylamine are added to this solution. After dissolving 20.3 g of terephthaloyl chloride in 100 ml of tetrahydrofuran from which water was removed, the mixture was stirred vigorously while slowly dropping into the solution containing the triazine monomer and triethylamine, and reacted for 12 hours. After completion of the reaction, the reaction solution was slowly poured into methanol, precipitated, and filtered. The precipitate was dried in vacuo. The obtained precipitate was again dissolved in tetrahydrofuran and then precipitated in methanol twice, and then vacuum-dried. Finally, a polyester-based polymer liquid crystal alignment having a chalcone photosensitive functional group was carried out using a triazine ring according to the present embodiment. The agent was synthesized.

(5) Fabrication of liquid crystal display elements

The obtained polyester photosensitive polymer liquid crystal aligning agent was dissolved in a mixed solvent of NMP and butyl cellussolve at a concentration of 8 wt%, and the solution was passed through a filtration membrane having a micropore size of 0.1 μm to remove undissolved impurity particles. . The solution is printed on a glass substrate 2 coated with a transparent electrode to a thickness of 50 to 500 nm to apply a photoalignment agent, and the glass substrate 2 is dried at 150 to 250 ° C. for about 1 to 2 hours to remove the solvent. It was. The glass substrate 2 is subjected to complex photoreaction such as photopolymerization of chalcone group and photodegradation of polymer chain through one light irradiation for 2 seconds to 10 minutes at an angle of 20 ° to ultraviolet light 4 of 500W mercury lamp. A polymer liquid crystal aligning film was prepared. The cell gap between the photoreacted two glass substrates 2 was attached to be 4-5 μm. The cell was cured for one hour at 130 ° C. to cure the epoxy adhesive so that the two glass substrates 2 were completely adhered to complete the manufacture of the cell. After injecting the liquid crystal into the finished cell was heated for 1 hour at 100 ~ 130 ℃ and then the heat treatment step of dropping the temperature back to room temperature was performed once. The electro-optical properties, thermal stability, light stability, residual DC and VHR characteristics of the liquid crystal cell after the heat treatment were measured, and the results are shown in Tables 1, 2, 3, and 4.

Example 3

Embodiment 3 relates to a polyester-based photosensitive liquid crystal aligning agent having a coumarin photosensitive functional group, a method for producing a liquid crystal alignment film 1 using the same, and a method for manufacturing a liquid crystal display device including the liquid crystal alignment film 1.

(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. 18.4 g of triazine was added to a round bottom flask, and the solution was dissolved in 200 ml of tetrahydrofuran from which moisture was removed. The solution was reacted vigorously with vigorous stirring at −5 ° C. for 24 hours. After the reaction was terminated, distillation under reduced pressure was carried out to remove tetrahydrfuran, 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 Diol Functional Group

 51.4 g of 4- (2-tetrahydropyranyloxy) bromobenzene was dissolved in 300 ml of water-removed tetrahydrofuran and reacted with 7.2 g of magnesium for 6 hours under nitrogen. 31.1 g of the triazine having the synthesized coumarin photosensitive functional group was dissolved in 300 ml of tetrahydrofuran from which water was removed, and then reacted with the Grignard reagent solution prepared above at room temperature for 12 hours. After terminating the reaction, 3 g of pyridinium paratoluenesulfonate was added to the reaction solution, and the reaction was further performed for 6 hours. Finally, 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, after recrystallization in 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 a monomer having a diol functional group.

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

45.5 g of the triazine monomer was placed in a round bottom flask filled with nitrogen and dissolved in 500 ml of tetrahydrofuran from which water was removed. 20.2 g of triethylamine are added to this solution. After dissolving 20.3 g of terephthaloyl chloride in 100 ml of tetrahydrofuran from which water was removed, the mixture was stirred vigorously while slowly dropping into the solution containing the triazine monomer and triethylamine, and reacted for 12 hours. After completion of the reaction, the reaction solution was slowly poured into methanol, precipitated, and filtered. The precipitate was dried in vacuo. The obtained precipitate was dissolved again in tetrahydrofuran and then precipitated in methanol twice, and then vacuum-dried to finally obtain a polyester-based polymer liquid crystal having a coumarin photosensitive functional group using a triazine ring according to this embodiment. The agent was synthesized.

(4) Fabrication of liquid crystal display elements

The obtained polyester photosensitive polymer liquid crystal aligning agent was dissolved in a mixed solvent of NMP and butyl cellussolve at a concentration of 8 wt%, and the solution was passed through a filtration membrane having a micropore size of 0.1 μm to remove undissolved impurity particles. . The solution is printed on a glass substrate 2 coated with a transparent electrode to a thickness of 50 to 500 nm to apply a photoalignment agent, and the glass substrate 2 is dried at 150 to 250 ° C. for about 1 to 2 hours to remove the solvent. It was. The glass substrate 2 was subjected to a complex photoreaction such as photopolymerization of coumarin groups and photolysis of polymer chains through one irradiation of light for 2 seconds to 10 minutes at an angle of 20 ° to the ultraviolet rays 4 of the 500W mercury lamp. The polymer liquid crystal aligning film 1 was manufactured. The cell gap between the photoreacted two glass substrates 2 was attached to be 4-5 μm. 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 2 were completely bonded to complete the manufacture of the cell. After injecting the liquid crystal into the finished cell was heated for 1 hour at 100 ~ 130 ℃ and then the heat treatment step of dropping the temperature back to room temperature was performed once. The electro-optical properties, thermal stability, light stability, residual DC and VHR characteristics of the liquid crystal cell after the heat treatment were measured, and the results are shown in Tables 1, 2, 3, and 4.

Table 1 shows the pretilt angle measurement results.

division Example 1 Example 2 Example 3 fair Light irradiation Light irradiation Light irradiation density 8wt% 8wt% 8wt% Pretilt Room temperature 0 to 5 ° 0 to 4 ° 0 to 4 ° After heat treatment 0 to 5 ° 0 to 4 ° 0 to 4 ° Contrast 195 190 190

* The pretilt angle was measured by the crystal angle rotation method.

* The heat treatment is carried out for 3 minutes at 150 ° C, the baking temperature.

The thermal stability of the liquid crystal display device according to Examples 1, 2, and 3 was evaluated by measuring the change of the pretilt angle with time at room temperature while measuring the initial linear time of the liquid crystal display and thermally aging at 200 ° C. It was. Table 2 shows the results of the thermal stability evaluation.

division Example 1 Example 2 Example 3 Pretilt To 5 ° To 4 ° ~ 4 ° Thermal aging temperature 200 ℃ 200 ℃ 200 ℃ Heat aging time 48 hours 48 hours 48 hours Pretilt variation none none none

In the case of unstable thermal stability, the pretilt angle changed over time. As shown in Table 2, the photo-alignment agent according to the present embodiment 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, and thus the basic characteristics for application to a liquid crystal display device. Satisfies

The liquid crystal display element for measuring photostability was manufactured by the method for manufacturing the liquid crystal display element according to Examples 1, 2, and 3. In the light stability measurement, the alignment surface of one liquid crystal display device was irradiated with ultraviolet light 4 and light in the visible light region for 1 to 10 minutes, and then the change of alignment characteristics of the irradiation surface and non-irradiation surface of the liquid crystal display device was visually confirmed. Table 3 shows the results of light stability evaluation.

division Example 1 Example 2 Example 3 Light irradiation 0.5J / cm ² No change No change No change 1 J / cm ² No change No change No change 2J / cm ² 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

In the present embodiment, as shown in Table 3, there is no change in the orientation characteristic, so it can be seen that the light stability is excellent. Accordingly, there is no problem in that the alignment characteristics of the liquid crystal are changed to show a sharp difference with the non-irradiated surface, or the alignment of the liquid crystal is broken so that the alignment direction of the liquid crystal is mixed in an unspecified direction and thus cannot be used in the display device.

Residual DC was applied to both ends of the liquid crystal display while varying the DC voltage between -10V and 10V. At this time, the capacitance was measured and the residual DC was calculated from the magnitude of the hysteresis value. The liquid crystal display element used in the experiment was prepared by the above-described manufacturing method with samples of the TN structure having a thickness of 4 ~ 6㎛. The two electrodes of the prepared liquid crystal display device were connected to an LCD meter (FLUKE 6306), and the change of capacitance was recorded at 1 kHz while the DC power was changed from 0 V to 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 로 at a period of ± 1 V and 60 Hz to measure the rate at which the initially applied voltage was maintained within one period. One result.

division Example 1 Example 2 Example 3 R-DC 20 ℃ 8 mV 9 mV 9 mV 60 ℃ 23 mV 26 mV 27 mV VHR 20 ℃ 99% 99% 98% 60 ℃ 99% 98% 97%

As shown in Table 4, low residual DCs of 10 to 13 mV were measured at 20 ° C. in Examples 1, 2, and 3, respectively, and the VHR was 98 to 99%. This indicates that the optical alignment agents according to the first, second and third embodiments of the present invention satisfy the basic characteristics for use as display elements.

As a result, the photopolymerized photo-degradable polyester-based polymer liquid crystal aligning agent using the triazine ring containing one or more photoactive groups according to Examples 1, 2, and 3 has thermal stability and optical transparency, which are basic characteristics of polyimide. It has excellent coating properties, high mechanical properties and the like, and also has a photosensitive functional group, so that the amount of light irradiation for orientation is reduced as compared with conventional polyimide alignment agents. When the photoalignment liquid crystal display device is manufactured using the alignment agent, a 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 silbaking, and thus the alignment characteristic of the liquid crystal is remarkably oriented. Therefore, it can be applied to a liquid crystal display device that requires high quality and wide viewing angle.

According to the present invention, low thermal stability due to weak physical bonding force between the low thermal stability liquid crystal and the alignment layer 1, which is a problem of the conventional optical alignment agent, in particular, a hydrocarbon-based optical alignment agent, is affected by light stability in the cell manufacturing process. Problems can be overcome, and at the same time, it has high mechanical properties, heat resistance, optical transparency, and chemical resistance which are characteristics of polyester-based polymers. As a result, the liquid crystal display according to the present invention can realize high quality and high quality display quality.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

1 is a schematic view showing an alignment process of a liquid crystal alignment film by a conventional rubbing method.

2 is a schematic view showing an irradiation step in the alignment process of the liquid crystal alignment film using the photosensitive polymer liquid crystal aligning agent composition according to the present invention.

<Brief description of the major reference numerals>

1: alignment film, 2: substrate,

3: rubbing drum, 4: ultraviolet rays.

Claims (11)

It has a structure of the following [Formula 1] having at least one photoactive group in the side chain and a triazine ring as a main chain, [Formula 1] One or more of the photoactive groups may be subjected to photolysis, the other may be subjected to fleece photolocation, and the other sites may be photodimerization, photoisomerization or photocrosslinking. Polyester-based photosensitive polymer liquid crystal aligning agent composition using triazine ring which has photoactive group. (In Formula 1, R ₁ is any one selected from the group consisting of the following formulas (1a), (2a), (3a), and (4a), In Formula (1a), X is any one selected from the group consisting of the following formulas, (Where m and n are each 0 to 10) Y in the formula (1a) is any one selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, and 9 are each one selected from the group consisting of the following formulas, (Where m and n are 0 to 10 and A and B are H, F, Cl, CN, CF ₃ or CH ₃ ) In Formulas (2a) and (3a), n is 0 to 10, and 1, 2, 3, 4, and 5 are each selected from the group consisting of the following formulas, (Where m and n are 0 to 10 and A and B are H, F, Cl, CN, CF ₃ or CH ₃ ) In Formula (4a), Y is any one selected from the group consisting of the following formulas, (N is 0 to 10 in the above formula.) In Formula (4a), 1 and 2 are each selected from the group consisting of the following formulas. (Wherein A is H, F, CH ₃ , CF ₃ , CN) In addition, in Chemical Formula 1, R ₂ and R ₃ are each one selected from the group consisting of the following formulas. (In the formula, m and n are each 0 to 10, and A and 1, 2, 3, 4, 5, 6, 7, and 8 are H, F, Cl, CN, CF ₃ or CH ₃ ). In addition, in Chemical Formula 1, R ₄ and R ₅ are each one selected from the group consisting of the following formulas. (Where m and n are each 0 to 10) delete delete delete The method of claim 1, The benzene ring is a polyester-based using a triazine ring having one or more photoactive groups, characterized in that further comprising an ortho- or meta-structure or a mixed structure of two or more of ortho-, meta-, para-structure Photosensitive polymer liquid crystal aligning agent composition. Dissolving a polyether photosensitive polymer liquid crystal aligning agent composition using a triazine ring having at least one photoactive group according to claim 1 in an organic solvent (S1); Applying the solution onto the substrate (2) by spin coating or printing to form an alignment layer (S2); And It characterized in that it comprises the step (S3) of inclined or vertical irradiation of the ultraviolet (4) linearly polarized using a polarizer on the surface of the alignment layer (1) or unpolarized ultraviolet (4) without using a polarizer The manufacturing method of the photosensitive polymer liquid crystal aligning film. The method of claim 6, The concentration of the organic solvent of the step S1 is 1 to 20wt% concentration and the viscosity is 1 to 1000cps method for producing a photosensitive polymer liquid crystal aligning film. The method of claim 6, The thickness of the alignment film (1) to be applied on the substrate (2) of the step S2 is 10 ~ 200nm manufacturing method of the photosensitive polymer liquid crystal alignment film. The method of claim 6, The organic solvent is chlorobenzene, N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N, N-dimethylimidazolidinone (DMI), N, N-dipropylimidazolidinone (DPI), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), cyclopentanone, cyclohexanone, dichloroethane, butylcellulose, gamma butyrolactone and tetrahydrofuran (THF Method for producing a photosensitive polymer liquid crystal aligning film, characterized in that any one or at least any two or more mixed solvents selected from the group consisting of A liquid crystal element comprising a liquid crystal aligning film (1) and a substrate (2) produced by claim 6. The method of claim 6, The step S3 is a method of manufacturing a photosensitive polymer liquid crystal alignment film, characterized in that it further comprises the step (S3-1) of forming a multi-domain using a photomask during ultraviolet irradiation.