WO2018032588A1

WO2018032588A1 - Liquid crystal aligning agent, liquid crystal alignment film and preparation method therefor, and liquid crystal display element

Info

Publication number: WO2018032588A1
Application number: PCT/CN2016/100866
Authority: WO
Inventors: 周雨生; 胡葆华; 王治国; 解万龙; 安隆隆; 苏俊伟
Original assignee: 中节能万润股份有限公司
Priority date: 2016-08-17
Filing date: 2016-09-29
Publication date: 2018-02-22
Also published as: TW201807065A; CN106318407A; TWI570184B

Abstract

Disclosed are a liquid crystal aligning agent, a liquid crystal alignment film and a preparation method therefor, and a liquid crystal display element, which belong to the technical field of liquid crystal display. The liquid crystal aligning agent comprises a polymer A obtained from a reaction of a mixture, and a solvent B, wherein the mixture contains a tetracarboxylic acid dianhydride component a and a diamine component b, and the diamine component b at least comprises diamine compound b-1 as shown in formula (I). Also disclosed are a liquid crystal alignment film prepared from the above-mentioned liquid crystal aligning agent and a preparation method therefor, and a liquid crystal display element. The liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a tert-butylphenol fragment and other tetracarboxylic acid dianhydride monomers. The liquid crystal alignment film of the present invention, when subjected to a photo-alignment exposure process, can enlarge a working window and has the dual advantage of exposure in an exposure zone being thorough and a non-exposure zone having an excellent ultraviolet resistance, and thus, the display effect and the service life of a liquid crystal display can be improved.

Description

Liquid crystal aligning agent, liquid crystal alignment film, preparation method thereof, and liquid crystal display element

Technical field

The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, a method for preparing the same, and a liquid crystal display element, and belongs to the field of liquid crystal display technology.

Background technique

The liquid crystal display is controlled by controlling the alignment state of the liquid crystal molecules. Usually, a liquid crystal alignment film is provided in the liquid crystal display element to control the initial alignment state of the liquid crystal molecules. As a liquid crystal alignment film, it is mainly a polyimide material which is excellent in high temperature resistance and the like. At present, the most popular orientation method in the industry is a fabric woven from fibers such as cotton, nylon, polyester, etc., rubbing in one direction. orientation. However, the rubbing orientation tends to generate dust and debris, and at the same time, it is easy to cause scratches on the liquid crystal alignment film. With the increasing demand for display quality and high-generation yield, the friction-oriented technology has gradually failed to meet the above requirements. Therefore, the industry is also developing new orientation technologies, among which photo-alignment technology is the fastest growing.

The so-called photo-alignment technology is a technique that uses light irradiation instead of the traditional cloth rubbing to achieve orientation. In the process of implementing this technology, deep ultraviolet light is generally used for de-irradiation. Generally, polyimide is used as an organic substance, and it is damaged by deep ultraviolet light irradiation. If the exposure is not good, it will cause The non-exposed area has an adverse effect, which affects the display effect. Therefore, the exposure process window of the current photo-alignment technology is narrow. In addition, when the liquid crystal display is in operation, it is inevitably exposed to ultraviolet light. As a core material, the ultraviolet resistance of the liquid crystal alignment film also determines the reliability and life of the liquid crystal display device.

Therefore, the development of polyimide materials with excellent UV resistance is essential for improving the working process of photo-alignment exposure processes and improving the reliability and lifetime of liquid crystal displays.

Summary of the invention

One of the objects of the present invention is to provide a liquid crystal aligning agent. The liquid crystal aligning agent of the present invention is obtained by polymerizing a diamine monomer containing a tert-butylphenol fragment and other tetracarboxylic dianhydride monomers; since the diamine monomer contains a t-butylphenol fragment, the polymerized material is resistant to ultraviolet rays. The performance of the liquid crystal alignment film of the present invention can increase the working window when performing the photo-alignment exposure process of the present invention, and has the dual advantages of excellent exposure of the exposed area and excellent ultraviolet resistance of the non-exposed area. Therefore, the display effect and the service life of the liquid crystal display can be improved.

The technical solution of the present invention to solve the above technical problems is as follows: a liquid crystal aligning agent comprising a polymer A obtained by reacting a mixture and a solvent B, wherein the mixture comprises a tetracarboxylic dianhydride component a and a diamine component b, The diamine component b includes at least the diamine compound b-1 represented by Formula I, and the diamine compound b-1 has the following structural formula:

Where X represents

single bond,

One of them.

Compared with the prior art, the liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a tert-butylphenol fragment and other tetracarboxylic dianhydride monomers; since the diamine monomer contains a tert-butylphenol fragment The polymer after polymerization has outstanding UV resistance. Therefore, the liquid crystal alignment film of the present invention can increase the working window when performing the photo-alignment exposure process of the present invention, and has the dual advantages of excellent exposure of the exposed area and excellent ultraviolet resistance of the non-exposed area, thereby improving The display effect and service life of the liquid crystal display. Based on the above technical solutions, the present invention can also be improved as follows.

Further, the polymer A is one of a polyamic acid, a polyimide, or a mixture of two.

Wherein, the preparation method of the above polyamic acid can be carried out by a conventional method, comprising the steps of dissolving a mixture comprising the tetracarboxylic dianhydride component a and the diamine component b in a solvent at 0-100 ° C. The polymerization reaction is carried out at a temperature for 1 to 24 hours to obtain a polyamic acid solution. The solvent may be distilled off under reduced pressure to obtain a polyamic acid solid, or the reaction system may be poured into a large amount of a poor solvent, and the precipitate may be dried to obtain a polyamide. Acid solid.

Further, the solvent B is N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylacetamide, N,N-dimethylformamide, ethylene glycol monomethyl ether, and B. a mixture of one or more of diol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol methyl ether, ethylene glycol dimethyl ether, and diethylene glycol monomethyl ether ethyl ester. Wherein the weight ratio of the polymer A to the solvent B is 1:5-80.

Further, the tetracarboxylic dianhydride component a is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3 , 5-tricarboxycyclopentyl acetic acid dianhydride, pyromellitic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-biphenyl a mixture of one or more of carboxylic acid dianhydride, 3,3', 4,4'-biphenyl sulfone tetracarboxylic dianhydride.

Further, the diamine compound b-1 may, for example, be a mixture of one or more of the formulae I-1 to I-4.

A further advantageous effect of the above is that if the liquid crystal aligning agent does not use the diamine compound b-1, the liquid crystal alignment film prepared from the liquid crystal aligning agent may have poor ultraviolet resistance, affecting the life of the liquid crystal display, and if used in a photo-alignment process, The exposure process window is narrow.

Further, the diamine component b further includes a diamine compound b-2, which is p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-di Aminonaphthalene, p-aminophenethylamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 1,4-bis (4 -aminophenoxy)benzene, 4,4'-diaminobenzophenone, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane , 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, N , N'-bis(4-aminophenyl)piperazine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,4-diaminododecyloxybenzene, 2 , 4-diaminooctadecyloxybenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane , 4-(4-heptylcyclohexyl)phenyl-3,5-diaminobenzoate, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-di Aminobenzamide, 1-(4-(4-pentylcyclohexylcyclohexyl)phenoxy)-2,4-diaminobenzene, 1-(4-(4-heptylcyclohexyl)phenoxy) -2,4-diaminobenzene, 3,5-diamine Mixtures of one or more of benzoic acid.

Further, the molar ratio of the tetracarboxylic dianhydride component a to the diamine component b is 100: 20-200.

Further, the molar ratio of the tetracarboxylic dianhydride component a to the diamine component b is from 100:80 to 120.

Further, the molar ratio of the tetracarboxylic dianhydride component a to the diamine compound b-1 is 100: 0.001-10.

Further, the molar ratio of the tetracarboxylic dianhydride component a to the diamine compound b-1 is 100:0.05-3.

The solvent used for the polymerization reaction may be the same as or different from the solvent B in the liquid crystal aligning agent, and the solvent used for the polymerization reaction is not particularly limited as long as the reactant can be dissolved. Solvents include, but are not limited to, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, γ-butyrolactone. Wherein the molar ratio of the mixture to the solvent is 1:5-80.

It is to be noted that the solvent for the polymerization reaction may be used in combination with an appropriate amount of a poor solvent, wherein the poor solvent does not cause precipitation of the polyamic acid. The poor solvent may be used singly or in combination, including but not limited to (1) alcohols: methanol, ethanol, isopropanol, cyclohexanol or ethylene glycol; (2) ketones: acetone, methyl ethyl ketone, methyl isobutyl ketone Or cyclobutanone; (3) esters: methyl acetate, ethyl acetate or butyl acetate; (4) ethers: ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether , ethylene glycol methyl ether, ethylene glycol dimethyl ether or tetrahydrofuran; (5) halogenated hydrocarbon: dichloromethane, chlorobenzene or 1,2-dichloroethane. Wherein the poor solvent accounts for 0-60% of the total weight of the solvent.

Based on the above technical solutions, the present invention can also be improved as follows.

Further, the poor solvent accounts for 0-30% of the total weight of the solvent.

The above preparation method for preparing a polyimide can be carried out by a conventional method comprising the steps of heating the polyamic acid obtained by the above method in the presence of a dehydrating agent and a catalyst.

During this process, the amic acid functional group in the polyamic acid is converted to an imide group by an imidization reaction.

The solvent of the imidization reaction may be the same as the solvent B in the liquid crystal aligning agent, and therefore will not be described again.

Wherein the weight ratio of the polyamic acid to the imidization reaction solvent is 1:5-30; the imidization ratio of the amic acid is 30-100%; the temperature of the imidization reaction is 0-100 ° C, the reaction time is 1-120 hours; the dehydrating agent may be selected from an acid anhydride compound such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride; the molar ratio of the polyamic acid to the dehydrating agent is 1:1-10; the catalyst may be selected from pyridine, trimethylamine or triethylamine; the molar ratio of the dehydrating agent to the catalyst is 1:0.1-5.

Further, the imidization ratio of the amic acid is 55 to 100%.

Further, the imidization reaction temperature is 20-60 ° C, and the reaction time is 2-30 hours.

The polyamic acid polymer and the polyimide compound are end-modified polymers adjusted by a molecular weight modifier without affecting the efficacy of the present invention. By using a terminal-modified polymer, the coating property of the liquid crystal aligning agent is improved. The terminal modified polymer can be produced by adding a molecular weight modifier to a polymerization reaction for preparing a polyamic acid. The molecular weight modifiers include, but are not limited to: (1) monobasic anhydrides such as maleic anhydride, phthalic anhydride or succinic anhydride; (2) monoamine compounds such as aniline, n-butylamine, n-pentylamine, n-hexylamine , n-heptylamine or n-octylamine; (3) a monoisocyanate compound such as phenyl isocyanate or naphthyl isocyanate. Wherein the molar ratio of the polyamic acid to the molecular weight modifier is 1:0.1.

Further, the molar ratio of the polyamic acid to the molecular weight modifier is 1:0.05.

The liquid crystal aligning agent according to the present invention contains an additive C without affecting the efficacy of the present invention. The additive C is an epoxy compound or a silane compound having a functional group. The additive C serves to improve the adhesion between the liquid crystal alignment film and the substrate, and the additive C may be used alone or in combination.

The epoxy compound includes, but is not limited to, ethylene glycol diepoxypropyl ether, polyethylene glycol diepoxypropyl ether, propylene glycol diepoxypropyl ether, polypropylene glycol diepoxypropyl ether, 1, 6-hexanediol epoxide Propyl ether, glycerol diepoxypropyl ether, N,N,N',N'-tetraepoxypropyl-m-xylylenediamine, N,N,N',N'-tetraepoxy Propyl-4,4'-diaminodiphenylmethane or 3-(N,N-diepoxypropyl)aminopropyltrimethoxysilane. Wherein the weight ratio of the polymer A to the epoxy compound is 100: 0.1-15.

Further, the weight ratio of the polymer A to the epoxy compound is 100:1-3.

The functional group-containing silane compound includes, but is not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 3-aminopropane Triethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N -Phenyl-3-aminopropyltrimethoxysilane or N-bis(ethylene oxide)-3-aminopropyltriethoxysilane. Wherein the weight ratio of the polymer A and the functional group-containing silane compound is 100:0-2.

Further, the weight ratio of the polymer A to the silane compound having a functional group is 100: 0.02 to 0.2.

The liquid crystal aligning agent can be obtained by mixing the polymer A and the additive C in a solvent B at 20 to 100 ° C with stirring.

Another object of the present invention is to provide a liquid crystal alignment film.

The technical solution of the present invention to solve the above technical problems is as follows: A liquid crystal alignment film made of the liquid crystal aligning agent as described above.

The liquid crystal aligning film of the present invention contains the liquid crystal aligning agent of the present invention, and the diamine monomer used in the aligning agent contains a tert-butylphenol fragment, and the material after polymerization has outstanding ultraviolet resistance. Therefore, the liquid crystal alignment film of the present invention is excellent. When performing the photo-alignment exposure process of the present invention, the working window can be increased, and the exposure of the exposed area and the non-exposed area have excellent ultraviolet resistance. Point, which can improve the display effect and service life of the liquid crystal display. In the embodiment, the liquid crystal display element prepared by using the alignment agent has ΔVHR (%) ≤ 5%, and is excellent in ultraviolet resistance.

Another object of the present invention is to provide a photo-alignment preparation method of the above liquid crystal alignment film. In the method for preparing a photo-alignment layer of the liquid crystal alignment film of the present invention, since exposure is performed after the pre-baking is completed, the exposure uniformity of the liquid crystal alignment film can be ensured, and the anchoring force of the liquid crystal alignment film to the liquid crystal can be improved, and at the same time The UV resistance of the orientation agent itself ensures that no overexposure occurs.

The technical solution of the present invention to solve the above technical problems is as follows: a photo-alignment preparation method of a liquid crystal alignment film, comprising the following steps:

(1) forming a precoat layer on a substrate by using the liquid crystal aligning agent as described above;

(2) pre-coating, primary exposure, post-baking, and double exposure of the pre-coating layer obtained in the step (1), that is, forming the liquid crystal alignment film;

Or pre-coating, pre-exposure, double exposure, post-baking of the pre-coating layer obtained in the step (1), that is, forming the liquid crystal alignment film;

Or the precoat layer obtained in the step (1) is pre-baked, once subjected to high-intensity exposure, and post-baked, that is, the liquid crystal alignment film is formed.

In the method for preparing a photo-alignment layer of the liquid crystal alignment film of the present invention, since exposure is performed after the pre-baking is completed, the exposure uniformity of the liquid crystal alignment film can be ensured, and the anchoring force of the liquid crystal alignment film to the liquid crystal can be improved, and at the same time The UV resistance of the orientation agent itself ensures that no overexposure occurs.

Further, the pre-baking temperature in the step (2) is 50-120 ° C, and the time is 2-7 mins.

Further, in the step (2), the light of the primary exposure and the double exposure is polarized light, and the wavelengths are different, and may be selected from a single 254 nm, or a single 313 nm, or a dual wavelength of 254 nm, 313 nm, and an exposure light intensity of 1-10 mW. /cm ² , the cumulative amount of exposure light is 10-1000 mj/cm ² .

Further, the post-baking temperature in the step (2) ranges from 180 to 250 ° C, and the time ranges from 30 to 90 mins.

Further, the light of the high-intensity exposure in the step (2) is polarized light, and may be selected from a single 254 nm, or a single 313 nm, or a dual wavelength of 254 nm and 313 nm, and the cumulative light amount of exposure is 20-2000 mj/cm ² .

The substrate in the above step (1) is a transparent material with a common electrode. The transparent material includes, but is not limited to, soda lime glass, hard glass, alkali-free glass, quartz glass, polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate. The common electrode may comprise a transparent conductive material such as ITO, IZO or ITZO.

The purpose of the prebaking described in the above step (2) is to remove most of the solvent in the precoat layer. The prebaking treatment has an operating temperature of 30 to 200 ° C, preferably 50 to 120 ° C, and the prebaking treatment time is 1 to 10 minutes, preferably 2 to 7 minutes.

The purpose of the post-baking described in the above step (2) is to increase the imidization ratio of the precoat layer. The post-baking treatment has an operating temperature of 80-300 ° C, preferably 180-250 ° C; the post-baking treatment time is 5-200 minutes, preferably 30-90 minutes; the pre-coating is post-baked film The thickness is from 0.01 to 0.5 μm, preferably from 0.05 to 0.2 μm.

The orientation treatment method is not particularly limited, and a fabric made of nylon, rayon, cotton, or other fibers may be wound around a drum and operated by rubbing in a certain direction.

A fourth object of the present invention is to provide a liquid crystal display element.

The technical solution of the present invention to solve the above technical problems is as follows: A liquid crystal display element made of the liquid crystal aligning agent as described above.

The liquid crystal display element of the present invention contains the liquid crystal aligning agent of the present invention, and the diamine monomer used in the aligning agent contains a tert-butylphenol fragment, and the material after polymerization has outstanding ultraviolet resistance, and therefore, the liquid crystal alignment film of the present invention When performing the photo-alignment exposure process of the present invention, the working window can be increased, and the service life of the liquid crystal display can be improved.

The method for preparing a liquid crystal display device comprises the steps of: preparing two substrates each having a liquid crystal alignment film thereon, and filling the liquid crystal between the two substrates to obtain a liquid crystal cell.

The liquid crystal display element produced by the liquid crystal aligning agent of the present invention is suitable for various liquid crystal display elements such as a twisted nematic (TN), a super twisted nematic (STN), a vertical alignment type (VA), and a coplanar switching type. (IPS) or fringe field switching (FFS). Among the above liquid crystal display elements, an IPS type liquid crystal display element is preferable.

The beneficial effects of the invention are:

1. Compared with the prior art, the liquid crystal aligning agent of the present invention is obtained by polymerizing a diamine monomer containing a tert-butylphenol fragment with other tetracarboxylic dianhydride monomers; since the diamine monomer contains tert-butylphenol The fragment and the polymerized material have outstanding ultraviolet resistance. Therefore, the liquid crystal alignment film of the present invention can increase the working window when performing the photo-alignment exposure process of the present invention, and has a fully exposed, non-exposed area having an exposed area. Excellent dual UV resistance, which can improve the display effect and service life of liquid crystal displays.

2. Compared with the prior art, the liquid crystal alignment film of the present invention has the dual advantages of complete exposure of the exposed region and excellent ultraviolet resistance of the non-exposed region.

3. In the method for preparing a photo-alignment film of the liquid crystal alignment film of the present invention, since exposure is performed after the pre-baking is completed, the exposure uniformity of the liquid crystal alignment film can be ensured, and the anchoring force of the liquid crystal alignment film to the liquid crystal can be improved, and at the same time Because of the ultraviolet resistance of the liquid crystal aligning agent itself, it is possible to ensure that overexposure does not occur.

4. Compared with the prior art, the liquid crystal display of the present invention has better display effect and longer service life.

5. The method of the invention has simple method and broad market prospect, and is suitable for large-scale application promotion.

DRAWINGS

Fig. 1 is a ¹ H-NMR chart of the compound b-1-3 in the present invention.

detailed description

The principles and features of the present invention are described in the following detailed description with reference to the accompanying drawings.

In the following specific examples, the liquid crystal aligning agent is described only by the IPS type liquid crystal display element, but the present invention is not limited thereto.

(1) Synthesis examples of compounds

Synthesis example of diamine compound b-1

Synthesis Example 1

The compound represented by the formula (I-1) can be synthesized according to the following Scheme 1:

Synthetic route 1

(1) Synthesis of compound b-1-1a

2,4-Dinitrophenol (110.5 g, 600 mmol), anhydrous potassium carbonate (82.9 g, 600 mmol) and 400 g of N,N-dimethylformamide were placed in a 1000 mL three-neck round bottom flask. The resulting red suspension was stirred at room temperature for 10 minutes, then the solution was warmed to 60 ° C with 2,6-di-tert-butyl-4-bromophenol (171.1 g, 600 mmol) and 300 g of N. A solution of N-dimethylformamide was dropped into the system and the system was exothermic. After all the solutions were added, the mixture was stirred at 60-65 ° C for 2 hours. After the reaction was completed by gas chromatography (GC), the stirring was stopped and then suction filtered. The obtained black filtrate was acidified to pH with dilute hydrochloric acid, and then 3 L of water was added thereto to precipitate a solid. The obtained suspension was suction filtered to obtain a yellow cake. The yellow cake was mixed with 200 g of ethanol/water and stirred for 30 minutes. After suction filtration and drying, a yellow solid compound will be obtained in a yield of 65%. (b-1-1a), GC-MS was tested after silicidation, m/z = 460.

(2) Synthesis of compound b-1-1

The obtained compound b-1-1a (38.8 g, 100 mmol), 5% palladium carbon (3.9 g, water, solid content: 30%) and 400 g of tetrahydrofuran were placed in a 1 L autoclave, and the autoclave was sealed. After the hydrogen gas was replaced 3-5 times, the hydrogen gas was pressurized to 0.5-1.0 MPa, and the reaction was carried out at 40-45 ° C with stirring. After completion of the reaction, the catalyst was removed through a film, and then the solvent was removed. The obtained solid was added to 100 g of ethanol and stirred for 30 minutes. After suction filtration and drying, a yellow solid compound b- was obtained in a yield of 95%. 1-1.

The ¹ H-NMR data (500 MHz, CHCl3-d1, δ, ppm) of the compound b-1-1 was: 1.33 (18H, 6×CH3), 5.38 (1H, OH), 5.75 (1H, CH-Ph) , 6.12 (1H, CH-Ph), 6.33 (4H, 2 x NH2), 6.75 (1H, CH-Ph), 7.13 (2H, 2 x CH-Ph).

Synthesis Example 2

The compound represented by the formula (I-2) can be synthesized according to the following Scheme 2:

Synthetic route 2

(1) Synthesis of compound b-1-2a

2,6-di-tert-butyl hydroquinone (44.4 g, 200 mmol), triethylamine (20.2 g, 200 mmol) and 400 g of tetrahydrofuran were placed in a 1000 mL three-neck round bottom flask, and the resulting suspension was After stirring at room temperature for 10 minutes, a colorless solution was obtained, and then the solution was cooled to 0 ° C, and a solution containing 3,5-dinitrobenzoyl chloride (46.1 g, 200 mmol) and 100 g of tetrahydrofuran was stirred under stirring. Instilled into the system, the system exotherms and controls the drop rate to maintain the internal temperature below 20 °C. After all the solutions were added, the mixture was stirred at 15 to 20 ° C for 2 hours. After the reaction was completed by gas chromatography (GC), the stirring was stopped and then suction filtered. The filtrate was poured into 2 L of water with stirring, and the resulting suspension was suction filtered to obtain a yellow cake. The water was mixed and stirred for 30 minutes, and after suction filtration and drying, a yellow solid compound b-1-2a was obtained in a yield of 80%.

(2) Synthesis of compound (b-1-2)

The obtained compound b-1-2a (41.6 g, 100 mmol), 5% palladium on carbon (4.2 g, aqueous, solid content: 30%) and 400 g of tetrahydrofuran were placed in a 1 L autoclave, and the autoclave was sealed. After the hydrogen gas was replaced 3-5 times, the hydrogen gas was pressurized to 0.5-1.0 MPa, and the reaction was carried out at 40-45 ° C with stirring. After completion of the reaction, the catalyst was removed by a film, and then the solvent was removed. The obtained solid was added to 300 g of ethanol and stirred for 30 minutes. After suction filtration and drying, a yellow solid compound b- was obtained in a yield of 93%. 1-2.

The ¹ H-NMR data (500 MHz, CHCl3-d1, δ, ppm) of the compound b-1-2 was: 1.36 (18H, 6×CH3), 5.42 (1H, OH), 6.08 (1H, CH-Ph) , 6.33 (4H, 2 x NH2), 6.66 (2H, 2 x CH-Ph), 7.28 (2H, 2 x CH-Ph).

Synthesis Example 3

The compound represented by the formula (I-3) can be synthesized according to the following Scheme 3:

Synthetic route 3

(1) Synthesis of compound b-1-3a

2,5-di-tert-butyl hydroquinone (133.4 g, 600 mmol), anhydrous potassium carbonate (82.9 g, 600 mmol) and 400 g of N in a 1000 mL three-neck round bottom flask under a nitrogen atmosphere. , N-dimethylformamide, the resulting red suspension was stirred at room temperature for 10 minutes, then the solution was warmed to 60 ° C, containing 2,4-dinitrochlorobenzene (121.5 g, 600 mils) with stirring. A solution of Mol) and 300 g of N,N-dimethylformamide was dropped into the system and the system was exothermic. After all the solutions were added, the mixture was stirred at 60-65 ° C for 2 hours. After the reaction was completed by gas chromatography (GC), the stirring was stopped and then filtered to remove inorganic salts and by-products. The obtained black filtrate was acidified to pH with dilute hydrochloric acid, and then 3 L of water was added thereto, and a viscous solid was precipitated from the system. The obtained viscous solid was recrystallized from ethyl acetate and toluene mixed solvent, filtered and dried. A yield of 35% gave a yellow solid compound b-1-3a.

(2) Synthesis of compound b-1-3

The obtained compound b-1-3a (38.8 g, 100 mmol), 5% palladium carbon (3.9 g, water, solid content: 30%), 400 g of tetrahydrofuran were placed in a 1 L autoclave, and the autoclave was sealed. After the hydrogen gas was replaced 3-5 times, the hydrogen gas was pressurized to 0.5-1.0 MPa, and the reaction was carried out at 40-45 ° C with stirring. After the reaction is completed, the catalyst is removed through a film, and then the solvent is removed, and the obtained solid is added to 100 g of B. The alcohol was stirred for 30 minutes, and after suction filtration and drying, a yellow solid compound b-1-3 was obtained in a yield of 89%.

As shown in Fig. 1, the ¹ H-NMR data (500 MHz, CHCl3-d1, δ, ppm) of the compound b-1-3 was: 1.28-1.38 (18H, 6 × CH3), 3.62 (4H, 2 × NH2) ), 4.68 (1H, OH), 6.05 (1H, CH-Ph), 6.22 (1H, CH-Ph), 6.50 (1H, CH-Ph), 6.63 (1H, CH-Ph), 6.68 (1H, CH) -Ph).

(2) Synthesis example of polymer A

Synthesis Example A-1-1

Under a nitrogen atmosphere, a diamine compound represented by the formula (I-1) (1.6 g, 5 mmol) (hereinafter referred to as b-1-1), p-phenylenediamine (5.4) was placed in a 1000 mL three-neck round bottom flask. g, 50 mmol) (hereinafter referred to as b-2-1), 1,2-bis(4-aminophenoxy)ethane (12.2 g, 50 mmol) (hereinafter referred to as b-2-2), Aminophenethylamine (19.7 g, 145 mmol) (hereinafter referred to as b-2-3) and 600 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were stirred until a yellow solution was obtained. Then, 49.0 g (250 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter a-1) and 100 g of NMP were added to the system. The reaction was exothermic and stirred at room temperature for 4 hours to obtain a polyamic acid polymer A-1-1 in NMP.

Synthesis Examples A-1-2 to A-1-20 and Comparative Synthesis Examples A-2-1 to A-2-5

Synthesis Examples A-1-2 to A-1-20 and Comparative Synthesis Examples A-2-1 to A-2-5 can be produced by the same method as Synthesis Example A-1-1 except that: The types and dosages of the bodies have changed. The specific results are shown in Table 1 and Table 2 below, and are not described here.

In Tables 1 and 2:

A-1:1,2,3,4-cyclobutane tetracarboxylic dianhydride

A-2: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride

A-3: pyromellitic dianhydride

A-4: 3,3',4,4'-biphenyltetracarboxylic dianhydride

B-1-1: a compound represented by formula (I-1)

B-1-2: a compound represented by formula (I-2)

B-1-3: a compound represented by formula (I-3)

B-2-1: p-phenylenediamine

B-2-2: 1,2-bis(4-aminophenoxy)ethane

B-2-3: p-aminophenylethylamine

B-2-4: 3,5-diaminobenzoic acid

B-2-5: 2,4-diaminododecyloxybenzene

B-2-6: 1-(4-(4-Heptylcyclohexyl)phenoxy)-2,4-diaminobenzene

B-2-7: 1-(4-(4-pentylcyclohexylcyclohexyl)phenoxy)-2,4-diaminobenzene

B-2-8: 4,4'-diaminodiphenylethane

Table 1 Types and amounts of monomers used in each polymer of the synthesis example

Table 2 Comparison of the types and amounts of monomers used in each polymer of the synthesis example

(III) Examples and Comparative Examples of Liquid Crystal Alignment Agent, Liquid Crystal Alignment Film, and Liquid Crystal Display Element

Example 1

a, liquid crystal aligning agent

100 parts by weight of the polymer (A-1-1), 900 parts by weight of NMP (hereinafter abbreviated as B-1), and 800 parts by weight of ethylene glycol monobutyl ether (hereinafter referred to as a short-bottomed flask) in a nitrogen atmosphere. B-2), the system was stirred at room temperature for 30 minutes, and then the solution was filtered through a 0.3 μm filter to form the liquid crystal aligning agent of Example 1.

b, liquid crystal alignment film and liquid crystal display element

The liquid crystal aligning agent of Example 1 was coated on a first glass substrate having an ITO electrode by spin coating to form a precoat layer. Pre-bake (hot plate, 80 ° C, 5 minutes), one exposure (254 nm, 5 mW/cm ² , 800 mj/cm ² ), post-baking (circulating oven, 230 ° C, 30 minutes) and double exposure (313 nm, 5 mW) /cm ² , 600 mj/cm ² ), a first glass substrate having the liquid crystal alignment film of Example 1 formed on the ITO electrode was obtained.

Coating the liquid crystal aligning agent of Example 1 on a piece of a sheet having no ITO electrode by spin coating On the two glass substrates to form a pre-coat. The second glass substrate on which the liquid crystal alignment film of Example 1 was formed was also obtained after the above prebaking, one exposure, post-baking, and double exposure.

A UV curable adhesive was applied to the periphery of one of the first glass substrate and the second glass substrate, and a 3.5 μm spacer was sprinkled on the other substrate. Then, the two glass substrates were attached in an anti-parallel manner to the orientation direction (5 kg, 30 min), and then the ultraviolet curable gel was cured by irradiation with an ultraviolet lamp. Then, the liquid crystal is injected, and then the liquid crystal injection port is sealed with ultraviolet light hardening glue, and the ultraviolet light hardening glue is hardened by ultraviolet light, and then the polarizing plate is attached to the outer side of the two glass substrates respectively, thereby obtaining the IPS of the first embodiment. Type liquid crystal display element.

The liquid crystal display element of Example 1 was evaluated, and the results are shown in Table 3.

Example 2 to Example 33

Examples 2 to 33 of the liquid crystal aligning agent, the liquid crystal aligning film, and the liquid crystal display element can be prepared by the same procedure as in Example 1, except that the polymer (A), the solvent (B), and the additive (C) are used. The type and amount of the product have changed, and the orientation process has also changed, see Table 3. The liquid crystal display elements of Examples 2 to 33 were evaluated and the results are shown in Table 3.

Comparative Example 1 to Comparative Example 7

Comparative Example 1 to Comparative Example 7 of a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element can be prepared by the same procedure as Example 1, except that the polymer (A), the solvent (B), and the additive are used. The type and amount of (C) have changed, and the orientation process has also changed, see Table 4. The liquid crystal display elements of Comparative Example 1 to Comparative Example 7 were evaluated and the results are shown in Table 4.

Evaluation method

UV resistance

The ultraviolet light resistance of the liquid crystal alignment film can be evaluated by the voltage holding ratio of the liquid crystal display element (hereinafter referred to as VHR). Further, the method of detecting the voltage holding ratio is as follows.

The condition for testing the VHR is to apply a voltage of 5 V, and after 60 ms, the voltage is released, and the VHR (denoted as VHR ₁ ) after 167 ms from the release voltage is measured. Then, the liquid crystal display element was placed under irradiation with 254 nm deep ultraviolet light at an irradiation intensity of 4,200 mj/cm2, and the VHR at this time (denoted as VHR ₂ ) was measured in the same manner. The change value of VHR (denoted as ΔVHR(%)) is then calculated by the formula (V), and the lower ΔVHR (%) means better thermal stability.

The evaluation criteria for ΔVHR(%) are as follows:

◎: ΔVHR (%) ≤ 5%, excellent UV resistance,

○: 5% < ΔVHR (%) ≤ 10%, good UV resistance

△: 10% < ΔVHR (%) ≤ 20%, general ultraviolet resistance

X: 20% < ΔVHR (%), poor UV resistance

In Tables 3 and 4:

B-1: N-methyl-2-pyrrolidone,

B-2: ethylene glycol monobutyl ether,

C-1: N, N, N', N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane,

C-2: 3-aminopropyltriethoxysilane.

Table 3 Evaluation results of liquid crystal display elements of Examples

Table 4 Evaluation results of liquid crystal display elements of Comparative Examples

In the table, *A: 254 nm, 5 mW/cm ² , 800 mj/cm ² ; *B: 313 nm, 5 mW/cm ² , 800 mj/cm ² ; *C: 254 nm, 10 mW/cm ² , 1000 mj/cm ² ; *D : dual wavelength (254 nm, 313 nm), 10 mW/cm ² , 800 mj/cm ² ; *E: dual wavelength (254 nm, 313 nm), 10 mW/cm ² , 1800 mj/cm ² .

It can be seen that the liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a tert-butylphenol fragment and other tetracarboxylic dianhydride monomers as compared with the prior art; The butyl phenol fragment has a prominent UV resistance property after polymerization. Therefore, in the liquid crystal alignment film of the present invention, when the photo-alignment exposure process of the present invention is performed, since the exposure is performed after the pre-baking is completed, the exposure uniformity of the liquid crystal alignment film can be ensured, and the liquid crystal alignment film can be improved. Anchoring force, and because of the UV resistance of the liquid crystal aligning agent itself, it can ensure that no overexposure occurs, and the working window can be enlarged. The exposure of the exposed area is complete, and the non-exposed area has the dual advantages of excellent UV resistance. Therefore, the display effect and the service life of the liquid crystal display can be improved. Moreover, the method is simple, the market prospect is broad, and it is suitable for large-scale application promotion.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims

A liquid crystal aligning agent comprising a polymer A obtained by reacting a mixture and a solvent B, wherein the mixture comprises a tetracarboxylic dianhydride component a and a diamine component b, and the diamine component b It includes at least the diamine compound b-1 represented by the formula I, and the diamine compound b-1 has the following structural formula:

Where X represents

single bond,
One of them.
The liquid crystal aligning agent according to claim 1, wherein the polymer A is one or a mixture of two of a polyamic acid and a polyimide.
The liquid crystal aligning agent according to claim 1, wherein the solvent B is N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylacetamide, N,N - in dimethylformamide, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol methyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether ethyl ester a mixture of one or more. Wherein the weight ratio of the polymer A to the solvent B is 1:5-80.
The liquid crystal aligning agent according to claim 1, wherein the tetracarboxylic dianhydride component a is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1, 2, 3 , 4-cyclopentane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, pyromellitic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid A mixture of one or more of anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride.
A liquid crystal aligning agent according to claim 1, wherein the diamine group Part b further includes a diamine compound b-2, which is p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, p-aminophenylethyl Amine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene , 4,4'-diaminobenzophenone, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-double ( 4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, N,N'-di(4) -aminophenyl)piperazine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,4-diaminododecyloxybenzene, 2,4-diamino- 18 Alkoxybenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4-(4-g Phenylcyclo)phenyl-3,5-diaminobenzoate, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzamide, 1- (4-(4-pentylcyclohexylcyclohexyl)phenoxy)-2,4-diaminobenzene, 1-(4-(4-heptylcyclohexyl)phenoxy)-2,4-diamino One of benzene, 3,5-diaminobenzoic acid or A mixture of species.
The liquid crystal aligning agent according to claim 1, wherein a molar ratio of the tetracarboxylic dianhydride component a to the diamine component b is from 100:20 to 200; The molar ratio of the dianhydride component a to the diamine compound b-1 is 100: 0.001 to 10.
A liquid crystal aligning film comprising the liquid crystal aligning agent according to any one of claims 1 to 6.
A photo-alignment preparation method for a liquid crystal alignment film according to claim 7, comprising the steps of:

(1) forming a precoat layer on a substrate by using the liquid crystal aligning agent as described above;

(2) pre-coating, primary exposure, post-baking, and double exposure of the pre-coating layer obtained in the step (1), that is, forming the liquid crystal alignment film;

Or pre-coating, pre-exposure, double exposure, post-baking of the pre-coating layer obtained in the step (1), that is, forming the liquid crystal alignment film;

Or the precoat layer obtained in the step (1) is pre-baked, once subjected to high-intensity exposure, and post-baked, that is, the liquid crystal alignment film is formed.
The photo-alignment preparation method of a liquid crystal alignment film according to claim 8, wherein the pre-baking temperature in the step (2) is 50-120 ° C, and the time is 2-7 mins; exposure to polarized light, the wavelength is different, selected from a single 254nm, 313nm or a single, double or wavelength 254nm, 313nm, light intensity of exposure 1-10mW / cm 2, accumulated light exposure amount 10-1000mj / cm 2 The post-baking temperature range is 180-250 ° C, the time range is 30-90 mins; the first high-intensity exposure light is polarized light, which may be selected from a single 254 nm, or a single 313 nm, or a dual wavelength 254 nm, 313 nm, The cumulative amount of exposure light is 20-2000 mj/cm 2 .
A liquid crystal display element produced by the liquid crystal aligning agent according to any one of claims 1 to 6.