TW201802142A - A liquid crystal alignment film and a liquid crystal display element having the liquid crystal alignment film - Google Patents

Abstract

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element having the liquid crystal alignment film. The liquid crystal alignment agent includes a polymer composition (A) and a solvent (B). The polymer composition (A) is obtained by reacting a mixture. The mixture includes a tetracarboxylic dianhydride component (a) and a diamine component (b). The diamine component (b) includes a diamine compound (b-1) represented by formula (I). As the bond energy of C-N of the acylamide group is stronger than both the bond energy of C-O of the ester group and the bond energy of C-O of the ether group, so by using the diamine compound having acylamide, the alignment film formed therefrom has an excellent thermal reliability and can improve the lifetime of the liquid crystal display devices.

Description

Liquid crystal aligning agent, liquid crystal aligning film, and liquid crystal display element

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

Polyimine is widely used in the electronics industry as the material with the highest thermal stability. For example, a polyimide film can be used as a liquid crystal alignment film, and a liquid crystal alignment film usually has a polyglycine or a polyimine. The polymer is coated on the surface of the substrate, and then a liquid crystal alignment film is obtained through a thermal process and an orientation process.

At present, as the demand for the long life of the liquid crystal display is continuously increased, the thermal stability requirement for the liquid crystal alignment film is also becoming stricter.

Therefore, how to provide a liquid crystal alignment film having excellent thermal stability is an urgent problem to be solved by those skilled in the art.

Since the CN bond bond in the guanamine group is stronger than the CO bond in the ether bond and the CO bond in the ester group, the liquid crystal alignment film made of the diamine compound containing a guanamine group can improve the liquid crystal. The life of the display.

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 contains a tetracarboxylic dianhydride component (a) and a second The amine component (b), the diamine component (b) at least comprising the diamine compound (b-1) represented by the formula I, the diamine compound (b-1) having the following structural formula:

Where X represents

中的一種，

One of them,

R ₁ represents a single bond, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

R ₂ represents a fluorine atom, a chlorine atom or a bromine atom,

R ₃ represents an alkyl group having 1-8 carbon atoms or an alkoxy group having 1-8 carbon atoms.

m ₁ represents an integer of 0-4,

m and n each independently represent an integer of 0-2.

Compared with the prior art, the liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a guanamine and other tetracarboxylic dianhydride monomers; since the guanamine group in the diamine monomer is more etheric and ester than the ester group Since the base of the liquid crystal aligning film of the present invention has excellent thermal stability and the like, the service life of the liquid crystal display can be improved.

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

Further, the polymer (A) is one or a mixture of two of polyamic acid and polyimine.

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, and The polymerization reaction is carried out at a temperature of 0 to 100 ° C for 1 to 24 hours, and then the solvent is distilled off under reduced pressure to obtain polylysine, or the reaction system is poured into a large amount of poor solvent, and the precipitate is dried to obtain polylysine. .

Further, the solvent (B) is N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylacetamide, N,N-dimethylformamide, ethylene glycol single A mixture of one or more of methyl ether, ethylene glycol 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'-linked a mixture of one or more of benzenetetracarboxylic dianhydride and 3,3',4,4'-biphenylfluorene tetracarboxylic dianhydride.

Further, the diamine compound (b-1) is a mixture of one or more of the formulae I-1 to I-5:

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 thermal stability for a long period of use.

Further, the diamine component (b) further includes a diamine compound (b-2) which is 1,4-diaminobenzene, 1,3-diaminobenzene, and 1 , 5-diaminonaphthalene, 1,8-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy) Benzene, 4,4'-diaminobenzophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 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'-diaminobenzamide, 1-(4-(4-heptylcyclohexyl)phenoxy)-2,4- A mixture of one or more of diaminobenzene and 3,5-diaminobenzoic acid.

Further, the molar ratio of the tetracarboxylic dianhydride component (a) to the diamine component (b) is from 100:20 to 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 from 100:5 to 90.

Further, the molar ratio of the tetracarboxylic dianhydride component (a) to the diamine compound (b-1) is from 100:20 to 80.

Further, the molar ratio of the tetracarboxylic dianhydride component (a) to the diamine compound (b-1) is from 100:30 to 70.

Further, the molar ratio of the diamine component (b) to the diamine compound (b-2) is from 100:30 to 90.

Further, the molar ratio of the diamine component (b) to the diamine compound (b-2) is from 100:40 to 80.

Further, the molar ratio of the diamine component (b) to the diamine compound (b-2) is from 100:50 to 70.

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, gamma-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 polyamidamine. 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 the polyimine 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 proline functional group in the poly-proline is converted to a quinone imine 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 proline is 30-100%; the imidization reaction The temperature 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 polyamic acid and the dehydrating agent The molar ratio 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.

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

Further, the imidization ratio of the proline is 55-100%. Further, the imidization reaction temperature is 20-60 ° C, and the reaction time is 2-30 hours.

The polyaminic acid polymer and the polyamidimide compound are terminal-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 the polymerization for preparing polyglycolic 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.

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

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 decane compound having a functional group. The additive (C) functions to increase the adhesion between the liquid crystal alignment film and the substrate, and the additive (C) may be used singly or in combination of two or more.

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 diepoxypropyl ether, glycerol diepoxypropyl ether, N,N,N',N'-tetraepoxypropyl-m-xylylenediamine, N,N,N ', N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane or 3-(N,N-diepoxypropyl)aminopropyltrimethoxydecane. Wherein the weight ratio of the polymer (A) to the epoxy compound is 100: 0.1-15.

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

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

The decane compound having a functional group includes, but is not limited to, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane, and 3-aminopropane. Triethoxy decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, N -Phenyl-3-aminopropyltrimethoxydecane or N-bis(ethylene oxide)-3-aminopropyltriethoxydecane. Wherein the weight ratio of the polymer (A) and the decane compound having a functional group is 100:0-2.

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

Further, the weight ratio of the polymer (A) and the decane 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 guanamine group in the diamine monomer used for the aligning agent is more stable than the ether group and the ester group. Therefore, the liquid crystal aligning film of the present invention has excellent heat. Stability and other advantages. In the embodiment, the liquid crystal display element prepared by using the alignment agent has ≤ 5 and excellent thermal stability.

The method for preparing the liquid crystal alignment film described above is a conventional method such as a roll coating method, a spin coating method, a printing coating method, an inkjet method, or the like, and includes the steps of: coating a liquid crystal aligning agent on a surface of a substrate to form a precoat layer; The precoat layer is subjected to a prebaking treatment and a post-baking treatment agent orientation treatment to form an oriented film.

The above-mentioned substrate is a transparent material with a common electrode. The transparent material includes, but is not limited to, soda lime glass, hard glass, enamel-free glass, quartz glass, polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate. The common electrode may comprise a transparent conductive material such as ITO, IZO or ITZO.

The purpose of this prebaking is to remove most of the solvent in the precoat. The prebaking treatment has an operating temperature of 30 to 200 ° C, preferably 40 to 150 ° C, and the prebaking treatment time is 1 to 10 minutes, preferably 2 to 5 minutes.

The purpose of this post-baking is to increase the imidization rate of the precoat layer. The post-baking treatment has an operating temperature of 80-300 ° C, preferably 120-250 ° C; the post-baking treatment time is 5-200 minutes, preferably 5-150 minutes; the pre-coating is post-baked film The thickness is from 0.01 to 1.0 μm, preferably from 0.05 to 0.5 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 third 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.

Since the liquid crystal display element of the present invention contains the liquid crystal aligning agent of the present invention, the guanamine group in the diamine monomer used for the aligning agent is more stable than the ether group and the ester group, and therefore, the liquid crystal alignment film of the present invention has excellent heat. The advantages of stability and the like can therefore increase the service life of the liquid crystal display.

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, a VA type liquid crystal display element is preferable.

The beneficial effects of the invention are:

Compared with the prior art, the liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a guanamine and other tetracarboxylic dianhydride monomers; since the guanamine group in the diamine monomer is more etheric and ester than the ester group Since the base of the liquid crystal aligning film of the present invention has excellent thermal stability and the like, the service life of the liquid crystal display can be improved.

The liquid crystal alignment film of the present invention has an advantage of excellent thermal stability and the like as compared with the prior art.

The liquid crystal display of the present invention has a longer service life than the prior art.

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

no

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

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 VA 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:

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

4'-(4-pentylcyclohexyl)-4-amino-biphenyl (32.2 g, 100 mmol), triethylamine (10.1 g, 100 mmol) and 400 g of tetrahydrofuran were placed in a 1000 mL three-neck round bottom flask. The resulting suspension was stirred at room temperature for 10 minutes to obtain a colorless solution, which was then cooled to 0 ° C and stirred to contain 2-(2,4-dinitrophenyl)acetamidine chloride ( A solution of 24.5 g, 100 mmol) and 80 g of tetrahydrofuran was added dropwise to the system, and the system exothermed to control 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 yellow cake was mixed with 200 g of ethanol. After stirring for 30 minutes, after suction filtration and drying, a yellow solid compound (b-1-1a) was obtained in a yield of 85%.

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

The obtained compound (b-1-1a) (53.0 g, 100 mmol), 5% palladium on carbon (5.3 g, aqueous, solid content: 30%) and 400 g of tetrahydrofuran were placed in a 1 L autoclave to seal the autoclave. After replacing 3-5 times with hydrogen, the hydrogen was pressurized to 0.5-1.0 MPa, and reacted 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 300 g of ethanol and stirred for 30 minutes. After suction filtration and drying, a yellow solid compound was obtained in a yield of 95% (b- 1-1).

The 1H-NMR data (500MHz, CHCl3-d1, δ, ppm) of the compound (b-1-1) are: 0.88 (3H, CH3), 1.25-1.31 (8H, 4×CH2), 1.43 (1H, CH) ), 1.52-1.86 (8H, 4×CH2-Cy), 2.72 (1H, CH-Cy), 5.31 (1H, NH), 3.55 (2H, CH2), 6.27 (4H, 2×NH2), 5.65-6.73 (3H, 3 x CH-Ph), 7.36-7.87 (8H, 8 x CH-Ph).

Synthesis Example 2

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

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

4-(4-pentylcyclohexyl)aniline (24.5 g, 100 mmol), triethylamine (10.1 g, 100 mmol) and 400 g of tetrahydrofuran were placed in a 1000 mL three-neck round bottom flask, and the resulting suspension was placed in the room. After stirring for 10 minutes at a temperature, a colorless solution was obtained, and then the solution was cooled to 0 ° C, and under stirring, 2-(2,4-dinitrophenyl)acetamidine chloride (24.5 g, 100 mmol) was added. A solution of 80 g of tetrahydrofuran was dropped into the system, and the system was exothermic, and the dropping rate was controlled to keep 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 yellow cake was mixed with 200 g of ethanol. After stirring for 30 minutes, after suction filtration and drying, a yellow solid compound (b-1-2a) was obtained in a yield of 83%.

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

The obtained compound (b-1-2a) (45.4 g, 100 mmol), 5% palladium on carbon (4.5 g, aqueous, solid content: 30%) and 400 g of tetrahydrofuran were placed in a 1 L autoclave to seal the autoclave. After replacing 3-5 times with hydrogen, the hydrogen was pressurized to 0.5-1.0 MPa, and reacted at 40-45 ° C with stirring. After the end of the reaction, the catalyst was removed through 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 was obtained in a yield of 90% (b- 1-2).

The ¹ H-NMR data (500 MHz, CHCl3-d1, δ, ppm) of the compound (b-1-2): 0.88 (3H, CH3), 1.25-1.31 (8H, 4×CH2), 1.43 (1H, CH), 1.52-1.86(8H,4×CH2-Cy), 2.72(1H,CH-Cy), 5.31 (1H,NH), 3.55 (2H,CH2), 6.27(4H,2×NH2), 5.65- 6.73 (3H, 3 × CH-Ph), 7.28-7.60 (4H, 4 × CH-Ph).

Synthesis Example 3

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

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

4-(4-pentylcyclohexyl)benzeneboronic acid (27.4 g, 100 mmol), 4-bromo-2-fluoro-aniline (19.1 g, 100 m) was placed in a 1000 mL three-neck round bottom flask under a nitrogen atmosphere. Molar), 30% aqueous sodium hydroxide solution (26.7 g, 200 mmol) and 400 g of ethanol, the resulting suspension was stirred at room temperature for 10 minutes to give a colorless solution of the catalyst Pd(OAc) ₂ (0.224 g, 1 mmol) was added to the system, the system was exothermic, the internal temperature was raised to 50-60 ° C, and then heated to reflux for 2 hours. After the reaction was completed by gas chromatography (GC), the stirring was stopped and then filtered, and the filter cake was mixed with 200 g of ethanol and kept stirring for 30 minutes. After suction filtration and drying, a yellow color was obtained in a yield of 93%. Solid compound (b-1-3a).

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

The obtained compound (b-1-3a) (34.0 g, 100 mmol), triethylamine (10.1 g, 100 mmol) and 400 g of tetrahydrofuran were placed in a 1000 mL three-neck round bottom flask, and the resulting suspension was allowed to stand at room temperature. After stirring for 10 minutes, a colorless solution was obtained, and then the solution was cooled to 0 ° C, and a solution containing 3.5-dinitrobenzimid chloride (23.1 g, 100 mmol) and 80 g of tetrahydrofuran was dropped into the system under stirring. In the system, the system is exothermic and the drip acceleration is controlled to keep 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 yellow cake was mixed with 200 g of ethanol. After stirring for 30 minutes, after suction filtration and drying, a yellow solid compound (b-1-3b) was obtained in a yield of 80%.

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

The obtained compound (b-1-3b) (53.4 g, 100 mmol), 5% palladium carbon (5.3 g, water, solid content: 30%), 400 g of tetrahydrofuran were charged in a 1 L autoclave, and the autoclave was sealed. After replacing 3-5 times with hydrogen, the hydrogen was pressurized to 0.5-1.0 MPa, and reacted at 40-45 ° C with stirring. After the end of the reaction, the catalyst was removed through 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 was obtained in a yield of 94% (b- 1-3).

As shown in Fig. 1, the ¹ H-NMR data (500 MHz, CHCl3-d1, δ, ppm) of the compound (b-1-3) was 0.88 (3H, CH3), 1.25-1.31 (8H, 4×CH2). ), 1.43(1H,CH), 1.52-1.86(8H,4×CH2-Cy), 2.72(1H,CH-Cy), 6.02(1H, CH-Ph), 6.27(4H, 2×NH2), 6.45 (2H, 2 × CH-Ph), 7.36-7.37 (4H, 4 × CH-Ph), 7.50 (1H, CH-Ph), 7.55 (1H, CH-Ph), 7.85 (1H, CH-Ph), 9.65 (1H, NH).

(2) Synthesis example of polymer (A)

Synthesis Example A-1-1

The diamine compound (47.0 g, 100 mmol) represented by the structural formula (I-1) (hereinafter referred to as b-1-1), 1,4-di, was placed in a 1000 mL three-neck round bottom flask under a nitrogen atmosphere. Aminobenzene (16.2 g, 150 mmol) (hereinafter referred to as b-2-1) and 600 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), the resulting suspension was 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 polyaminic acid polymer (A-1-1) in NMP.

Synthesis Example A-1-2 to Comparative Synthesis Example A-2-1 to A-2-4

Synthesis Example A-1-2 to Comparative Synthesis Examples A-2-1 to A-2-4 were prepared in the same manner as in Synthesis Example A-1-1 except that the types and amounts of the monomers used were 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: 1,4-diaminobenzene

B-2-2: 4,4'-diaminobiphenylmethane

B-2-3: 4,4'-diaminodiphenyl ether

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

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

Table 2 compares 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 above liquid crystal aligning agent was applied by spin coating to two glass substrates each having an ITO electrode to form a precoat layer. After prebaking (hot plate, 100 ° C, 5 minutes) and post baking (return oven, Two liquid crystal alignment films were obtained at 220 ° C for 30 minutes, and the two liquid crystal alignment films were subjected to rubbing treatment (roller diameter: 150 mm, rotation speed: 500 rpm, moving speed: 20 mm/s, press-in amount: 0.5 mm).

After the rubbing treatment, an ultraviolet curable adhesive was applied to the periphery of one of the two glass substrates, and a 3.5 μm spacer was sprinkled on the other substrate. The two glass substrates were then bonded (5 kg, 30 mIn) and then cured with a UV lamp to cure the UV curable adhesive. Then, the liquid crystal was injected and cooked with a hot plate (60 ° C, 30 mIn) to obtain the liquid crystal display element of Example 1.

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

Embodiment 2 to Embodiment 20

Examples 2 to 20 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, see Table 3. The liquid crystal display elements of Examples 2 to 20 were evaluated and the results are shown in Table 3.

Comparative Example 1 to Comparative Example 6

Comparative Example 1 to Comparative Example 6 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, see Table 4. The liquid crystal display elements of Comparative Example 1 to Comparative Example 6 were evaluated and the results are shown in Table 4.

Evaluation method

a, thermal stability

The thermal stability 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 detection method of 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 VHR1) after 167 ms from the release voltage is measured. The liquid crystal display element was then placed in an oven (60 ° C) for 500 h, then cooled to room temperature, and the VHR at this time (denoted as VHR 2 ) was measured in the same manner. The change in VHR is then calculated by equation (V) (denoted as ), and the lower the value, the better the thermal stability.

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

◎: ΔVHR (%) ≦ 5%, excellent thermal stability,

○: 5% < ΔVHR (%) ≦ 20%, and the thermal stability is good.

X: ΔVHR (%)>20%, and thermal stability is poor.

b, vertical orientation

The liquid crystal display element was observed from the vertical direction by no voltage under a polarizing microscope and an applied AC voltage of 6 V (peak to peak).

The evaluation criteria are as follows:

○: There is no light leakage,

X: A bad white display appears.

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-aminopropyltriethoxydecane.

Table 3 Evaluation results of liquid crystal display elements of Examples

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

It can be seen that, compared with the prior art, the liquid crystal aligning agent of the present invention is formed by polymerizing a diamine monomer containing a guanamine and other tetracarboxylic dianhydride monomers; Since the ether group and the ester group are more stable, the liquid crystal alignment film of the present invention has excellent thermal stability and the like, and can improve the service life of the liquid crystal display. 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 (10)

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 amine component (b) 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 In one of them, R ₁ represents a single bond, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, R ₂ represents a fluorine atom, a chlorine atom or a bromine atom, and R ₃ represents a carbon number of 1 to 8. Alkyl or alkoxy having 1-8 carbon atoms, m ₁ represents an integer of 0-4, and m and n each independently represent an integer of 0-2. A liquid crystal aligning agent according to claim 1, wherein the polymer (A) is one or a mixture of two of polyamic acid and polyimine. A liquid crystal aligning agent according to claim 1, wherein the solvent (B) is N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylacetamide, N, N-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 of them. A 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'-biphenylfluorene tetracarboxylic dianhydride. A liquid crystal aligning agent according to claim 1, wherein the diamine component (b) further comprises a diamine compound (b-2), and the diamine compound (b-2) is 1,4- Diaminobenzene, 1,3-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 4,4'-diaminobenzophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 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'-diaminobenzamide, 1-(4-(4-g A mixture of one or more of cyclohexyl)phenoxy)-2,4-diaminobenzene and 3,5-diaminobenzoic acid. A 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. A liquid crystal aligning agent according to claim 6, wherein the tetracarboxylic dianhydride component (a) and the diamine component (b) have a molar ratio of 100:80 to 120. A liquid crystal aligning agent according to claim 1, wherein a molar ratio of the tetracarboxylic dianhydride component (a) to the diamine compound (b-1) is from 100:5 to 90. A liquid crystal aligning film which is produced by the liquid crystal aligning agent of any one of Claims 1-7. A liquid crystal display element produced by the liquid crystal aligning agent according to any one of claims 1 to 7.