Liquid crystal alignment agent composition, method of producing liquid crystal alignment film using the same, and liquid crystal alignment film using the same

Abstract

A liquid crystal alignment agent composition for producing a liquid crystal alignment film having enhanced alignment property and stability and a high voltage holding ratio, a method of producing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the same, are provided.

Claims

1. A liquid crystal alignment agent composition comprising a first polymer including two or more repeating units selected from the group of a repeating unit represented by Chemical Formula 1, a repeating unit represented by Chemical Formula 2, and a repeating unit represented by Chemical Formula 3, wherein the repeating unit represented by the following Chemical Formula 1 is included in an amount of 5 mol % to 74 mol % with respect to a total of the repeating units represented by the following Chemical Formulae 1 to 3; and a second polymer including one or more repeating units selected from the group of a repeating unit represented by Chemical Formula 4, a repeating unit represented by Chemical Formula 5, and a repeating unit represented by Chemical Formula 6: ##STR00025## wherein, in Chemical Formulae 1 to 6, R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each independently hydrogen or a C.sub.1-10 alkyl, provided that R.sup.1 and R.sup.2 are not both hydrogen, and that R.sup.3 and R.sup.4 are not both hydrogen, X.sup.1 is a tetravalent organic group represented by Chemical Formula 7: ##STR00026## wherein, in Chemical Formula 7, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are each independently hydrogen or a C.sub.1-6 alkyl, X.sup.2, X.sup.3, X.sup.4, X.sup.5, and X.sup.6 are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms wherein one or more of H is substituted with a halogen, or one or more of —CH.sub.2— is substituted with —O—, —CO—, —S—, —SO—, —SO.sub.2—, or —CONH— to prevent direct binding with oxygen or sulfur atoms in the tetravalent organic group, in Chemical Formulae 1 to 3, Y.sup.1 to Y.sup.3 are each independently a divalent organic group represented by Chemical Formula 8: ##STR00027## wherein, in Chemical Formula 8, R.sup.9 and R.sup.10 are each independently a halogen, a cyano, a C.sub.1-10 alkyl, a C.sub.2-10 alkenyl, a C.sub.1-10 alkoxy, a C.sub.1-10 fluoroalkyl, or a C.sub.1-10 fluoroalkoxy, p and q are each independently an integer of 0 to 4, L.sup.1 is a single bond, —O—, —CO—, —S—, —SO.sub.2—, —C(CH.sub.3).sub.2—, —C(CF.sub.3).sub.2—, —CONH—, —COO—, —(CH.sub.2).sub.z—, —O(CH.sub.2).sub.zO—, —O(CH.sub.2).sub.z—, —OCH.sub.2—C(CH.sub.3).sub.2—CH.sub.2O—, —COO—(CH.sub.2).sub.z—OCO—, or —OCO—(CH.sub.2).sub.z—COO—, wherein z is an integer of 1 to 10, k and m are each independently an integer of 1 to 3, n is an integer of 0 to 3, in Chemical Formulae 4 to 6, Z.sup.1, Z.sup.2, and Z.sup.3 are each independently a divalent organic group represented by Chemical Formula 9: ##STR00028## wherein, in Chemical Formula 9, A.sup.1 is oxygen, sulfur, selenium, tellurium or polonium, and A.sup.2, A.sup.3, A.sup.4, and A.sup.5 are nitrogen or carbon, provided that at least one of A.sup.2 to A.sup.5 is nitrogen and the others are carbon.

2. The liquid crystal alignment agent composition of claim 1, wherein X.sup.2, X.sup.3, X.sup.4, X.sup.5, and X.sup.6 are each independently a tetravalent organic group represented by Chemical Formula 10: ##STR00029## wherein, in Chemical Formula 10, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are each independently hydrogen or a C.sub.1-6 alkyl, R.sup.12 and R.sup.13 are each independently hydrogen or a C.sub.1-10 alkyl, and L.sup.2 is any one selected from the group consisting of a single bond, —O—, —CO—, —S—, —SO—, —SO.sub.2—, —CR.sup.14R.sup.15—, —CONH—, —COO—, —(CH.sub.2).sub.b—, —O(CH.sub.2).sub.bO—, —COO—(CH.sub.2).sub.b—OCO—, —HN—(CH.sub.2).sub.b—NH—, —R.sup.14N—(CH.sub.2).sub.b—NR.sup.15—, phenylene, and combinations thereof, wherein R.sup.14 and R.sup.15 are each independently hydrogen, a C.sub.1-10 alkyl, or a C.sub.1-10 fluoroalkyl, and each b is independently an integer of 1 to 10.

3. The liquid crystal alignment agent composition of claim 1, wherein Chemical Formula 8 is a divalent organic group represented by Chemical Formula 11 or Chemical Formula 12: ##STR00030## wherein, in Chemical Formula 12, L.sup.3 is a single bond, —O—, —SO.sub.2—, or —CR.sup.16R.sup.17—, wherein R.sup.16 and R.sup.17 are each independently hydrogen or a C.sub.1-10 alkyl.

4. The liquid crystal alignment agent composition of claim 1, wherein in Chemical Formula 9, any one of A.sup.2 to A.sup.5 is nitrogen and the others are carbon.

5. The liquid crystal alignment agent composition of claim 1, wherein in Chemical Formula 9, A.sup.2 or A.sup.5 is nitrogen and the other is carbon, and A.sup.3 and A.sup.4 are carbon.

6. The liquid crystal alignment agent composition of claim 1, wherein Chemical Formula 9 includes one or more repeating units selected from the group of the following Chemical Formula 9-1, Chemical Formula 9-2, and Chemical Formula 9-3: ##STR00031## wherein, in Chemical Formulae 9-1 to 9-3, A.sup.1 to A.sup.5, and a are as defined in claim 1.

7. The liquid crystal alignment agent composition of claim 1, wherein the first polymer for the first liquid crystal alignment agent and the second polymer for the second liquid crystal alignment agent are included at a weight ratio of 5:95 to 95:5.

8. The liquid crystal alignment agent composition of claim 1, wherein the second polymer for the second liquid crystal alignment agent further includes one or more repeating units selected from the group of a repeating unit represented by Chemical Formula 13, a repeating unit represented by Chemical Formula 14, and a repeating unit represented by Chemical Formula 15: ##STR00032## wherein, in Chemical Formulae 13 to 15, at least one of R.sup.18 and R.sup.19 is an alkyl group having 1 to 10 carbon atoms and the other is hydrogen, X.sup.7 to X.sup.9 are each independently a tetravalent organic group, and Z.sup.4 to Z.sup.6 are each independently a divalent organic group represented by the following Chemical Formula 16: ##STR00033## wherein, in Chemical Formula 16, R.sup.20 and R.sup.21 are each independently a halogen, a cyano, a C.sub.1-10 alkyl, a C.sub.2-10 alkenyl, a C.sub.1-10 alkoxy, a C.sub.1-10 fluoroalkyl, or a C.sub.1-10 fluoroalkoxy, p′ and q′ are each independently an integer of 0 to 4, L.sup.4 is a single bond, —O—, —CO—, —S—, —SO.sub.2—, —C(CH.sub.3).sub.2—, —C(CF.sub.3).sub.2—, —CONH—, —COO—, —(CH.sub.2).sub.z—, —O(CH.sub.2).sub.zO—, —O(CH.sub.2).sub.z—, —OCH.sub.2—C(CH.sub.3).sub.2—CH.sub.2O—, —COO—(CH.sub.2).sub.z—OCO—, or —OCO—(CH.sub.2).sub.z—COO—, wherein each z is independently an integer of 1 to 10, k′ and m′ are each independently an integer of 0 to 3, and n′ is an integer of 0 to 3.

9. The liquid crystal alignment agent composition of claim 8, wherein the Chemical Formula 16 is the following Chemical Formula 17 or Chemical Formula 18: ##STR00034## wherein, in Chemical Formula 18, L.sup.5 is a single bond, —O—, —SO.sub.2—, or —CR.sup.22R.sup.23—, wherein R.sup.22 and R.sup.23 are each independently hydrogen or a C.sub.1-10 alkyl.

10. A method of producing a liquid crystal alignment film, the method comprising the steps of: coating the liquid crystal alignment agent composition of claim 1 onto a substrate to form a coating film; drying the coating film; irradiating the coating film with light immediately after the step of drying the coating film to perform an alignment treatment; and heat-treating and curing the alignment-treated coating film.

11. The method of producing a liquid crystal alignment film of claim 10, wherein the liquid crystal alignment agent composition is dissolved or dispersed in an organic solvent.

12. The method of producing a liquid crystal alignment film of claim 10, wherein the step of drying the coating film is performed at 50° C. to 150° C.

13. The method of producing a liquid crystal alignment film of claim 10, wherein in the alignment treatment step, the light irradiation is performed by irradiating polarized ultraviolet rays having a wavelength of 150 nm to 450 nm.

14. The method of producing a liquid crystal alignment film of claim 10, wherein in the step of heat-treating and curing the coating film, the heat treatment temperature is 150° C. to 300° C.

15. A liquid crystal alignment film which is produced by the method of claim 10.

16. A liquid crystal display device comprising the liquid crystal alignment film of claim 15.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) The present invention will be described in more detail in the following examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not intended to be limited thereby.

PREPARATION EXAMPLE

Preparation Example 1: Preparation of Diamine DA1-1

(2) Preparation was performed as in the following reaction scheme.

(3) ##STR00017##

(4) Specifically, CBDA (cyclobutane-1,2,3,4-tetracarboxylic dianhydride, compound 1) and 4-nitroaniline were dissolved in DMF (dimethylformamide) to prepare a mixture. Subsequently, this mixture was allowed to react at about 80° C. for about 12 hours to prepare an amic acid of a compound 2. Thereafter, the amic acid was dissolved in DMF, and acetic anhydride and sodium acetate were added thereto to prepare a mixture. Subsequently, the amic acid in the mixture was subjected to imidization at about 90° C. for about 4 hours to prepare a compound 3. An imide of the compound 3 thus prepared was dissolved in DMAc (dimethylacetamide), and then Pd/C was added thereto to prepare a mixture. This mixture was reduced at about 45° C. under hydrogen pressure of about 6 bar for about 20 hours to prepare a diamine DA1-1.

Preparation Example 2: Preparation of Diamine DA1-2

(5) ##STR00018##

(6) DA1-2 was prepared in the same manner as in Preparation Example 1, except that DMCBDA (1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride) was used instead of CBDA (cyclobutane-1,2,3,4-tetracarboxylic dianhydride).

Preparation Example 3: Synthesis of Diamine DA1-3

(7) Preparation was performed as in the following reaction scheme.

(8) ##STR00019##

(9) Specifically, 25 g of CBDA (cyclobutane-1,2,3,4-tetracarboxylic dianhydride, compound 1) was added to 250 mL of methanol, and 1 to 2 drops of hydrochloric acid was added thereto, and heated under reflux at about 75° C. for about 5 hours. The solvent was removed under reduced pressure, and 300 mL of ethyl acetate and n-hexane were added for solidification. A produced solid was filtered under reduced pressure and dried under reduced pressure at about 40° C. to obtain 32 g of a compound 4.

(10) 100 mL of toluene was added to 34 g of the obtained compound 4, and 35 g of oxalyl chloride was added dropwise at room temperature. 2 to 3 drops of dimethylformamide (DMF) was added dropwise and stirred at about 50° C. for about 16 hours. After cooling to room temperature, the solvent and remaining oxalyl chloride were removed under reduced pressure. 300 mL of n-hexane was added to a yellow solid product and heated under reflux at about 80° C. The heated reaction solution was filtered to remove impurities which were not dissolved in n-hexane, and slowly cooled to room temperature. A produced white crystal was filtered and then dried in a vacuum oven at about 40° C. to obtain 32.6 g of a compound 5.

(11) 29.6 g of 4-nitroaniline and 21.7 g of triethanolamine (TEA) were added to about 400 mL of tetrahydrofuran (THF), and 32.6 g of compound 5 was added thereto at room temperature. After stirring at room temperature for about 16 hours, a produced precipitate was filtered. About 400 ml of dichloromethane was added to a filtrate, followed by washing with a 0.1 N hydrochloric acid aqueous solution and then washing with a saturated sodium hydrogen carbonate (NaHCO.sub.3) aqueous solution. The washed organic solution was filtered under reduced pressure to obtain a solid product. The product was recrystallized from dichloromethane to obtain 43 g of a solid-phase dinitro compound 6.

(12) 43 g of the dinitro compound 6 thus obtained was put in a high-pressure reactor and dissolved in about 500 mL of THF. 2.2 g of 10 wt % Pd/C was added thereto, followed by stirring under hydrogen gas (H.sub.2) at 3 atm for about 16 hours at room temperature. After reaction, Pd—C was removed using a Celite filter. After filtration, a filtrate was concentrated under reduced pressure to obtain 37 g of esterified diamine DA1-3.

Preparation Example 4: Synthesis of Diamine DA2-1

(13) ##STR00020##

(14) 17.1 g (100 mmol) of 2-chloro-5-nitropyridine (compound 7) and 12.5 g (98.6 mmol) of 4-nitrophenol (compound 8) were completely dissolved in about 200 mL of dimethyl sulfoxide (DMSO), and then 27.2 g (200 mmol) of potassium carbonate (K.sub.2CO.sub.3) was added thereto, and stirred at room temperature for about 16 hours. When the reaction was completed, the reaction product was put in a container containing about 500 mL of water, followed by stirring for about 1 hour. A solid obtained by filtration was washed with about 200 mL of water and about 200 mL of ethanol to obtain 16 g (61.3 mmol) of a diamine compound 9 (yield: 57%).

(15) ##STR00021##

(16) The compound 9 was dissolved in about 200 mL of a 1:1 mixture of ethyl acetate (EA) and THF, and then 0.8 g of palladium/carbon (Pd/C) was added, followed by stirring under a hydrogen atmosphere for about 12 hours. After completion of the reaction, a filtrate filtered through a Celite pad was concentrated to obtain 11 g of a diamine compound DA2-1 (pODA) (yield: 89%).

Preparation Example 5: Synthesis of Diamine DA2-2

(17) ##STR00022##

(18) A diamine compound DA2-2 was prepared in the same manner as in Preparation Example 4, except that 3-nitrophenol was used instead of 4-nitrophenol (compound 8).

Preparation Example 6: Synthesis of Diamine DA2

(19) ##STR00023##

(20) A diamine compound DA2-3 was prepared in the same manner as in Preparation Example 4, except that 2-chloro-4-nitropyridine was used instead of 2-chloro-5-nitropyridine (compound 7).

SYNTHESIS EXAMPLE

Synthesis Examples 1 to 4 and Comparative Synthesis Example 1

(21) Synthesis of First Polymer

Synthesis Example 1: Preparation of Polymer P-1 for Liquid Crystal Alignment Agent

(22) 5.0 g (13.3 mmol) of DA1-1 prepared in Preparation Example 1 was completely dissolved in 71.27 g of anhydrous N-methyl pyrrolidone (NMP). In an ice bath, 2.92 g (13.03 mmol) of 1,3-dimethyl-cyclobutane-1,2,3,4-tetracarboxylic dianhydride (DMCBDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer P-1 for a liquid crystal alignment agent.

(23) A molecular weight of the polymer P-1 was confirmed by GPC, and as a result, its number average molecular weight (Mn) was 15,500 g/mol and its weight average molecular weight (Mw) was 31,000 g/mol. A monomer structure of the polymer P-1 is determined by an equivalent ratio of the used monomer, and in the molecule, a ratio of the imide structure was 50.5%, and a ratio of the amic acid structure was 49.5%.

Synthesis Example 2: Preparation of Polymer P-2 for Liquid Crystal Alignment Agent

(24) 5.376 g of DA1-2 prepared in Preparation Example 2 was first dissolved in 74.66 g of NMP, and 2.92 g of 1,3-dimethyl-cyclobutane-1,2,3,4-tetracarboxylic dianhydride (DMCBDA) was added thereto, and stirred at room temperature for about 16 hours. Thereafter, a polymer P-2 was prepared in the same manner as in Synthesis Example 1.

(25) A molecular weight of the polymer P-2 was confirmed by GPC, and as a result, its number average molecular weight (Mn) was 17,300 g/mol and its weight average molecular weight (Mw) was 34,000 g/mol. In the molecule of the polymer P-2, a ratio of the imide structure was 50.5%, and a ratio of the amic acid structure was 49.5%.

Synthesis Example 3: Preparation of Polymer P-3 for Liquid Crystal Alignment Agent

(26) 5.0 g of DA1-2 prepared in Preparation Example 2 and 1.07 g of p-phenylenediamine were first dissolved in 89.81 g of NMP, and 1.90 g of cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 3.00 g of oxydiphthalic dianhydride were added thereto, and stirred at room temperature for about 16 hours to prepare a polymer P-3.

(27) A molecular weight of the polymer P-3 was confirmed by GPC, and as a result, its number average molecular weight (Mn) was 17,000 g/mol and its weight average molecular weight (Mw) was 33,000 g/mol. In the molecule of the polymer P-3, a ratio of the imide structure was 33.8%, and a ratio of the amic acid structure was 66.2%.

Synthesis Example 4: Preparation of Polymer P-4 for Liquid Crystal Alignment Agent

(28) 5.0 g of DA1-1 prepared in Preparation Example 2 and 3.93 g of DA1-3 prepared in Preparation Example 3 were first dissolved in 127.94 g of NMP, and then 5.28 g of cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) was added thereto, and stirred for about 16 hours at room temperature to prepare a polymer P-4 for a liquid crystal alignment agent.

Comparative Synthesis Example 1: Preparation of Polymer PR-1 for Liquid Crystal Alignment Agent

(29) 6.00 g of p-phenylenediamine was first dissolved in 156.9 g of NMP, and 5.34 g of cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 6.10 g of 1,3-dimethyl-cyclobutane-1,2,3,4-tetracarboxylic dianhydride (DMCBDA) were added thereto, and stirred for about 16 hours at room temperature to prepare a polymer PR-1.

(30) A molecular weight of the polymer PR-1 was confirmed by GPC, and as a result, its number average molecular weight (Mn) was 15,000 g/mol and its weight average molecular weight (Mw) was 28,000 g/mol. The monomer structure of the polymer PR-1 was analyzed, and as a result, a ratio of the amic acid structure in the molecule was 100%.

Synthesis Examples 5 to 25 and Comparative Synthesis Examples 2 to 7: Synthesis of Second Polymer

Synthesis Example 5: Polymer Q-1 for Liquid Crystal Alignment Agent

(31) 19.840 g (0.099 mmol) of diamine DA2-1 prepared in Preparation Example 4 was completely dissolved in 225.761 g of anhydrous N-methyl pyrrolidone (NMP).

(32) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-1 for a liquid crystal alignment agent. A molecular weight of the polymer Q-1 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 27,000 g/mol.

Synthesis Example 6: Polymer Q-2 for Liquid Crystal Alignment Agent

(33) 14.708 g (0.073 mmol) of diamine DA2-1 prepared in Preparation Example 4 was completely dissolved in 196.681 g of anhydrous N-methyl pyrrolidone (NMP).

(34) In an ice bath, 20.0 g (0.068 mmol) of 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride (BPDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-2 for a liquid crystal alignment agent. A molecular weight of the polymer Q-2 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 23,000 g/mol.

Synthesis Example 7: Polymer Q-3 for Liquid Crystal Alignment Agent

(35) 19.305 g (0.096 mmol) of diamine DA2-1 prepared in Preparation Example 4 was completely dissolved in 222.726 g of anhydrous N-methyl pyrrolidone (NMP).

(36) In an ice bath, 20.0 g (0.089 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-3 for a liquid crystal alignment agent. A molecular weight of the polymer Q-3 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,500 g/mol.

Synthesis Example 8: Polymer Q-4 for Liquid Crystal Alignment Agent

(37) 1.984 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 9.596 g (0.089 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 178.952 g of anhydrous N-methyl pyrrolidone (NMP).

(38) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-4 for a liquid crystal alignment agent. A molecular weight of the polymer Q-4 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 24,000 g/mol.

Synthesis Example 9: Polymer Q-5 for Liquid Crystal Alignment Agent

(39) 9.920 g (0.049 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 5.331 g (0.049 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 199.756 g of anhydrous N-methyl pyrrolidone (NMP).

(40) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-5 for a liquid crystal alignment agent. A molecular weight of the polymer Q-5 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 27,000 g/mol.

Synthesis Example 10: Polymer Q-6 for Liquid Crystal Alignment Agent

(41) 1.984 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 17.768 g (0.089 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 225.263 g of anhydrous N-methyl pyrrolidone (NMP).

(42) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-6 for a liquid crystal alignment agent. A molecular weight of the polymer Q-6 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 27,000 g/mol.

Synthesis Example 11: Polymer Q-7 for Liquid Crystal Alignment Agent

(43) 9.920 g (0.049 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 9.871 g (0.049 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 225.484 g of anhydrous N-methyl pyrrolidone (NMP).

(44) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-7 for a liquid crystal alignment agent. A molecular weight of the polymer Q-7 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 27,500 g/mol.

Synthesis Example 12: Polymer Q-8 for Liquid Crystal Alignment Agent

(45) 1.984 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 17.593 g (0.089 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 224.272 g of anhydrous N-methyl pyrrolidone (NMP).

(46) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-8 for a liquid crystal alignment agent. A molecular weight of the polymer Q-8 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 28,500 g/mol.

Synthesis Example 13: Polymer Q-9 for Liquid Crystal Alignment Agent

(47) 9.920 g (0.049 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 9.774 g (0.049 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 224.934 g of anhydrous N-methyl pyrrolidone (NMP).

(48) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-9 for a liquid crystal alignment agent. A molecular weight of the polymer Q-9 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 28,500 g/mol.

Synthesis Example 14: Polymer Q-10 for Liquid Crystal Alignment Agent

(49) 1.471 g (0.007 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 7.114 g (0.066 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 161.980 g of anhydrous N-methyl pyrrolidone (NMP).

(50) In an ice bath, 20.0 g (0.068 mmol) of 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride (BPDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-10 for a liquid crystal alignment agent. A molecular weight of the polymer Q-10 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 25,500 g/mol.

Synthesis Example 15: Polymer Q-11 for Liquid Crystal Alignment Agent

(51) 1.471 g (0.007 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 13.172 g (0.066 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 196.312 g of anhydrous N-methyl pyrrolidone (NMP).

(52) In an ice bath, 20.0 g (0.068 mmol) of 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride (BPDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-11 for a liquid crystal alignment agent. A molecular weight of the polymer Q-11 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 25,000 g/mol.

Synthesis Example 16: Polymer Q-12 for Liquid Crystal Alignment Agent

(53) 1.471 g (0.007 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 13.043 g (0.066 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 195.578 g of anhydrous N-methyl pyrrolidone (NMP).

(54) In an ice bath, 20.0 g (0.068 mmol) of 3,3′,4,4′-biphenyl tetracarboxylic acid dianhydride (BPDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-12 for a liquid crystal alignment agent. A molecular weight of the polymer Q-12 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,000 g/mol.

Synthesis Example 17: Polymer Q-13 for Liquid Crystal Alignment Agent

(55) 1.930 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 9.337 g (0.086 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 177.181 g of anhydrous N-methyl pyrrolidone (NMP).

(56) In an ice bath, 20.0 g (0.089 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-13 for a liquid crystal alignment agent. A molecular weight of the polymer Q-13 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 25,500 g/mol.

Synthesis Example 18: Polymer Q-14 for Liquid Crystal Alignment Agent

(57) 1.930 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 17.289 g (0.086 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 222.242 g of anhydrous N-methyl pyrrolidone (NMP).

(58) In an ice bath, 20.0 g (0.089 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-14 for a liquid crystal alignment agent. A molecular weight of the polymer Q-14 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,500 g/mol.

Synthesis Example 19: Polymer Q-15 for Liquid Crystal Alignment Agent

(59) 1.930 g (0.01 mmol) of diamine DA2-1 prepared in Preparation Example 4 and 17.119 g (0.086 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 221.278 g of anhydrous N-methyl pyrrolidone (NMP).

(60) In an ice bath, 20.0 g (0.089 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-15 for a liquid crystal alignment agent. A molecular weight of the polymer Q-15 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 25,500 g/mol.

Synthesis Example 20: Polymer Q-16 for Liquid Crystal Alignment Agent

(61) 1.984 g (0.01 mmol) of diamine DA2-2 prepared in Preparation Example 5 and 9.596 g (0.089 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 178.952 g of anhydrous N-methyl pyrrolidone (NMP).

(62) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-16 for a liquid crystal alignment agent. A molecular weight of the polymer Q-16 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 22,000 g/mol.

Synthesis Example 21: Polymer Q-17 for Liquid Crystal Alignment Agent

(63) 1.984 g (0.01 mmol) of diamine DA2-2 prepared in Preparation Example 5 and 17.768 g (0.089 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 225.263 g of anhydrous N-methyl pyrrolidone (NMP).

(64) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-17 for a liquid crystal alignment agent. A molecular weight of the polymer Q-17 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,500 g/mol.

Synthesis Example 22: Polymer Q-18 for Liquid Crystal Alignment Agent

(65) 1.984 g (0.01 mmol) of diamine DA2-2 prepared in Preparation Example 5 and 17.593 g (0.089 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 224.272 g of anhydrous N-methyl pyrrolidone (NMP).

(66) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-18 for a liquid crystal alignment agent. A molecular weight of the polymer Q-18 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 24,500 g/mol.

Synthesis Example 23: Polymer Q-19 for Liquid Crystal Alignment Agent

(67) 1.984 g (0.01 mmol) of diamine DA2-3 prepared in Preparation Example 6 and 9.596 g (0.089 mmol) of p-phenylenediamine (p-PDA) were completely dissolved in 178.952 g of anhydrous N-methyl pyrrolidone (NMP).

(68) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-19 for a liquid crystal alignment agent. A molecular weight of the polymer Q-19 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 22,500 g/mol.

Synthesis Example 24: Polymer Q-20 for Liquid Crystal Alignment Agent

(69) 1.984 g (0.01 mmol) of diamine DA2-3 prepared in Preparation Example 6 and 17.768 g (0.089 mmol) of 4,4′-oxydianiline (ODA) were completely dissolved in 225.263 g of anhydrous N-methyl pyrrolidone (NMP).

(70) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-20 for a liquid crystal alignment agent. A molecular weight of the polymer Q-20 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 24,500 g/mol.

Synthesis Example 25: Polymer Q-21 for Liquid Crystal Alignment Agent

(71) 1.984 g (0.01 mmol) of diamine DA2-3 prepared in Preparation Example 6 and 17.593 g (0.089 mmol) of 4,4′-methylenedianiline (MDA) were completely dissolved in 224.272 g of anhydrous N-methyl pyrrolidone (NMP).

(72) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer Q-21 for a liquid crystal alignment agent. A molecular weight of the polymer Q-21 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,000 g/mol.

Comparative Synthesis Example 2: Polymer QR-1 for Liquid Crystal Alignment Agent

(73) 26.852 g (0.099 mmol) of p-phenylenediamine (p-PDA) was completely dissolved in 265.496 g of anhydrous N-methyl pyrrolidone (NMP).

(74) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer QR-1 for a liquid crystal alignment agent. A molecular weight of the polymer QR-1 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 26,000 g/mol.

Comparative Synthesis Example 3: Polymer QR-2 for Liquid Crystal Alignment Agent

(75) 19.743 g (0.099 mmol) of 4,4′-oxydianiline (ODA) was completely dissolved in 225.208 g of anhydrous N-methyl pyrrolidone (NMP).

(76) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer QR-2 for a liquid crystal alignment agent. A molecular weight of the polymer QR-2 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 21,000 g/mol.

Comparative Synthesis Example 4: Polymer QR-3 for Liquid Crystal Alignment Agent

(77) 19.548 g (0.089 mmol) of 4,4′-methylenedianiline (MDA) was completely dissolved in 224.218 g of anhydrous N-methyl pyrrolidone (NMP).

(78) In an ice bath, 20.0 g (0.092 mmol) of pyromellitic dianhydride (PMDA) was added to the solution, and stirred at room temperature for about 16 hours to prepare a polymer QR-3 for a liquid crystal alignment agent. A molecular weight of the polymer QR-3 was confirmed by GPC, and as a result, its weight average molecular weight (Mw) was 23,000 g/mol.

Comparative Synthesis Example 5: Polymer S-1 for Liquid Crystal Alignment Agent

(79) A polymer S-1 for a liquid crystal alignment agent was prepared in the same manner as in Synthesis Example 1, except that 2,6-bis(trifluoromethyl)-4,4′-diaminodiphenyl ether represented by the following Chemical Formula A was used instead of diamine DA2-1 prepared in Preparation Example 4.

(80) ##STR00024##

EXAMPLE

Example 1: Preparation of Liquid Crystal Alignment Agent Composition

(81) According to the composition as shown in the following Table 1, 10 g of the polymer P-1 for a liquid crystal alignment agent prepared in Synthesis Example 1 and 10 g of the polymer Q-1 for a liquid crystal alignment agent prepared in Synthesis Example 5 were added to 12.4 g of NMP and 7.6 g of n-butoxyethanol (a weight ratio of 8:2) to prepare a 5 wt % solution. The obtained solution was filtered through a poly(tetrafluoroethylene) filter having a pore size of 0.1 μm under pressure to prepare a liquid crystal alignment agent composition.

Example 2: Preparation of Liquid Crystal Alignment Agent Composition

(82) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that the polymer P-3 for a liquid crystal alignment agent was used instead of the polymer P-1 for a liquid crystal alignment agent.

Example 3: Preparation of Liquid Crystal Alignment Agent Composition

(83) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that the polymer P-4 for a liquid crystal alignment agent was used instead of the polymer P-1 for a liquid crystal alignment agent.

Examples 4 to 23: Preparation of Liquid Crystal Alignment Agent Compositions

(84) According to the composition as shown in the following Table 1, each liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that each of the polymers Q-2 to Q-21 for a liquid crystal alignment agent was used instead of the polymer Q-1 for a liquid crystal alignment agent.

Example 24: Preparation of Liquid Crystal Alignment Agent Composition

(85) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that the polymer P-2 for a liquid crystal alignment agent prepared in Synthesis Example 2 was used instead of the polymer P-1 for a liquid crystal alignment agent, and the polymer Q-4 for a liquid crystal alignment agent was used instead of the polymer Q-1 for a liquid crystal alignment agent.

Examples 25 to 27: Preparation of Liquid Crystal Alignment Agent Compositions

(86) According to the composition as shown in the following Table 1, each liquid crystal alignment agent composition was prepared in the same manner as in Example 24, except that each of the polymers Q-10 to Q-12 for a liquid crystal alignment agent was used instead of the polymer Q-4 for a liquid crystal alignment agent.

Example 28: Preparation of Liquid Crystal Alignment Agent Composition

(87) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 24, except that 4 g of the polymer P-2 for a liquid crystal alignment agent and 16 g of the polymer Q-4 for a liquid crystal alignment agent were added.

Examples 29 to 31: Preparation of Liquid Crystal Alignment Agent Compositions

(88) According to the composition as shown in the following Table 1, each liquid crystal alignment agent composition was prepared in the same manner as in Example 28, except that each of the polymers Q-10 to Q-12 for a liquid crystal alignment agent was used instead of the polymer Q-4 for a liquid crystal alignment agent.

Comparative Example 1: Preparation of Liquid Crystal Alignment Agent Composition

(89) A liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that 20 g of the polymer P-1 for a liquid crystal alignment agent was added without using the polymer Q-1 for a liquid crystal alignment agent.

Comparative Example 2: Preparation of Liquid Crystal Alignment Agent Composition

(90) A liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that 20 g of the polymer Q-1 for a liquid crystal alignment agent was added without using the polymer P-1 for a liquid crystal alignment agent.

Comparative Example 3: Preparation of Liquid Crystal Alignment Agent Composition

(91) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that the polymer PR-1 for a liquid crystal alignment agent was used instead of the polymer P-1 for a liquid crystal alignment agent.

Comparative Examples 4 to 6: Preparation of Liquid Crystal Alignment Agent Compositions

(92) According to the composition as shown in the following Table 1, each liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that each of the polymers QR-1 to QR-3 for a liquid crystal alignment agent was used instead of the polymer Q-1 for a liquid crystal alignment agent.

Comparative Example 7: Preparation of Liquid Crystal Alignment Agent Composition

(93) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Comparative Example 5, except that the polymer P-3 for a liquid crystal alignment agent was used instead of the polymer P-1 for a liquid crystal alignment agent.

Comparative Example 8: Preparation of Liquid Crystal Alignment Agent Composition

(94) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Comparative Example 6, except that the polymer P-4 for a liquid crystal alignment agent was used instead of the polymer P-1 for a liquid crystal alignment agent.

Comparative Example 9: Preparation of Liquid Crystal Alignment Agent Composition

(95) According to the composition as shown in the following Table 1, a liquid crystal alignment agent composition was prepared in the same manner as in Example 1, except that the polymer S-1 for a liquid crystal alignment agent was used instead of the polymer Q-1 for a liquid crystal alignment agent.

(96) The polymer compositions of the liquid crystal alignment agent compositions according to Examples 1 to 31 and Comparative Examples 1 to 9 are as shown in the following Table 1.

(97) TABLE-US-00001 TABLE 1 Mixing weight First polymer Second polymer ratio of first and Input Input second Type (g) Type (g) polymers Example 1 P-1 10 Q-1 10 50:50 Example 2 P-3 10 Q-1 10 50:50 Example 3 P-4 10 Q-1 10 50:50 Example 4 P-1 10 Q-2 10 50:50 Example 5 P-1 10 Q-3 10 50:50 Example 6 P-1 10 Q-4 10 50:50 Example 7 P-1 10 Q-5 10 50:50 Example 8 P-1 10 Q-6 10 50:50 Example 9 P-1 10 Q-7 10 50:50 Example 10 P-1 10 Q-8 10 50:50 Example 11 P-1 10 Q-9 10 50:50 Example 12 P-1 10 Q-10 10 50:50 Example 13 P-1 10 Q-11 10 50:50 Example 14 P-1 10 Q-12 10 50:50 Example 15 P-1 10 Q-13 10 50:50 Example 16 P-1 10 Q-14 10 50:50 Example 17 P-1 10 Q-15 10 50:50 Example 18 P-1 10 Q-16 10 50:50 Example 19 P-1 10 Q-17 10 50:50 Example 20 P-1 10 Q-18 10 50:50 Example 21 P-1 10 Q-19 10 50:50 Example 22 P-1 10 Q-20 10 50:50 Example 23 P-1 10 Q-21 10 50:50 Example 24 P-2 10 Q-4 10 50:50 Example 25 P-2 10 Q-10 10 50:50 Example 26 P-2 10 Q-11 10 50:50 Example 27 P-2 10 Q-12 10 50:50 Example 28 P-2 4 Q-4 16 20:80 Example 29 P-2 4 Q-10 16 20:80 Example 30 P-2 4 Q-11 16 20:80 Example 31 P-2 4 Q-12 16 20:80 Comparative P-1 20 — — 100:0  Example 1 Comparative — — Q-1 20  0:100 Example 2 Comparative PR-1 10 Q-1 10 50:50 Example 3 Comparative P-1 10 QR-1 10 50:50 Example 4 Comparative P-1 10 QR-2 10 50:50 Example 5 Comparative P-1 10 QR-3 10 50:50 Example 6 Comparative P-3 10 QR-2 10 50:50 Example 7 Comparative P-4 10 QR-3 10 50:50 Example 8 Comparative P-1 10 S-1 10 50:50 Example 9

EXPERIMENTAL EXAMPLE

(98) 1) Preparation of Liquid Crystal Alignment Cell

(99) Each of the liquid crystal alignment agent compositions prepared in the examples and comparative examples was used to prepare a liquid crystal alignment cell.

(100) Specifically, the liquid crystal alignment agent composition was coated onto the upper and lower substrates for a voltage holding ratio (VHR), in which ITO electrodes with a thickness of 60 nm and an area of 1 cm×1 cm were patterned on a square glass substrate with a size of 2.5 cm×2.7 cm, by a spin coating method, respectively. Then, the substrates coated with the liquid crystal alignment agent were placed on a hot plate at about 70° C. and dried for 3 minutes to evaporate the solvent. For alignment treatment of the coated substrates thus obtained, each of upper and lower coated substrates was irradiated with UV at 254 nm under an exposure dose of 0.1 to 1.0 J/cm.sup.2 using an exposure equipped with a line polarizer. Thereafter, the alignment-treated upper and lower substrates were baked (cured) in an oven at about 230° C. for about 30 minutes to obtain a coating film with a thickness of 0.1 μm. Thereafter, a sealing agent impregnated with ball spacers with a size of 4.5 μm was coated onto the edges of the upper substrate excluding a liquid crystal inlet. The alignment films formed on the upper and lower substrates were then aligned such that they faced each other and the alignment directions were aligned with each other, and the upper and lower substrates were bonded together and the sealing agent was cured with UV and heat to prepare an empty cell. Then, a liquid crystal was injected into the empty cells, and the inlet was sealed with a sealing agent to prepare a liquid crystal cell.

(101) 2) Evaluation of Liquid Crystal Alignment Property

(102) Polarizing plates were attached to the upper and lower substrate plates of the above-prepared liquid crystal cell so as to be perpendicular to each other. At this time, the polarizing axis of the polarizing plate attached to the lower substrate plate was allowed to be parallel to the alignment axis of the liquid crystal cell. The polarizing plate-attached liquid crystal cell was placed on a backlight having luminance of 7000 cd/cm.sup.2, and light leakage was observed with the naked eye. When the liquid crystal alignment film had an excellent alignment property to align liquid crystals properly, light did not pass through the upper and lower polarizing plates which were attached perpendicular to each other, and the liquid crystal cell was observed dark without defects. In this case, the alignment property was recorded as ‘good’. When light leakage such as a liquid crystal flow mark or a bright spot was observed, it was recorded as ‘poor’ in Table 2 below.

(103) 3) Evaluation of Liquid Crystal Alignment Stability

(104) Polarizing plates were attached to the upper and lower substrate plates of the above-prepared liquid crystal alignment cell so as to be perpendicular to each other. The polarizing plate-attached liquid crystal alignment cell was attached on a backlight having luminance of 7000 cd/cm.sup.2, and the luminance in a black state was measured using a luminance measuring instrument PR-880. Then, the liquid crystal cell was operated at room temperature with an alternating voltage of 5 V for 24 hours. Thereafter, in the voltage-off state of the liquid crystal cell, luminance in the black state was measured as described above. A difference between the initial luminance (L.sub.0) measured before operation of the liquid crystal cell and the later luminance (L.sub.1) measured after operation was divided by the initial luminance (L.sub.0), and then multiplied by 100 to calculate a luminance fluctuation rate. As the calculated luminance fluctuation rate is close to 0%, it means that the alignment stability is excellent. Through the measurement results of the luminance fluctuation rate, the afterimage level was evaluated under the following criteria. It is preferable that the AC afterimage is minimized. In the measurement results, when the luminance fluctuation rate was less than 10%, it was evaluated as ‘excellent’, when the luminance fluctuation rate was between 10% to 20%, it was evaluated as ‘ordinary’, and when the luminance fluctuation rate was more than 20%, it was evaluated as ‘poor’. The results are shown in Table 2 below.

(105) 4) Measurement of Voltage Holding Ratio (VHR)

(106) Liquid crystal cells for voltage holding ratio were prepared using the liquid crystal alignment agents prepared in Examples 1 to 31 and Comparative Examples 1 to 9 by the following method, respectively.

(107) The liquid crystal alignment agent was coated onto the upper and lower substrates for a voltage holding ratio (VHR), in which ITO electrodes with a thickness of 60 nm and an area of 1 cm×1 cm were patterned on a square glass substrate with a size of 2.5 cm×2.7 cm, by a spin coating method, respectively.

(108) Then, the substrates coated with the liquid crystal alignment agent were placed on a hot plate at about 70° C. and dried for 3 minutes to evaporate the solvent. For alignment treatment of the coated substrates thus obtained, each of upper and lower coated substrates was irradiated with UV at 254 nm under an exposure dose of 1 J/cm.sup.2 using an exposure equipped with a line polarizer. Thereafter, the alignment-treated upper and lower substrates were baked and cured in an oven at about 230° C. for 30 minutes to obtain a coating film with a thickness of 0.1 μm. Thereafter, a sealing agent impregnated with ball spacers with a size of 4.5 μm was coated onto the edges of the upper/lower substrate excluding a liquid crystal inlet. The alignment films formed on the upper and lower substrates were then aligned such that they faced each other and the alignment directions were aligned with each other, and the upper and lower substrates were bonded together and the sealing agent was cured with UV and heat to prepare an empty cell. Then, a liquid crystal was injected into the empty cells, and the inlet was sealed with a sealing agent to prepare a liquid crystal cell.

(109) The voltage holding ratio (VHR) which is an electrical property of the liquid crystal cell prepared by the above method was measured using TOYO 6254 equipment. The voltage holding ratio was measured under harsh conditions of 1 V, 1 Hz, and 60° C. The voltage holding ratio of 100% is an ideal value. When the measurement result is 70% or more, it is evaluated as ‘good’, and when the measurement result is less than 70%, it is evaluated as ‘poor’, and the results are shown in Table 2 below.

(110) TABLE-US-00002 TABLE 2 Evaluation of liquid Evaluation of liquid Evaluation of crystal alignment crystal alignment voltage holding property stability ratio Example 1 Good Excellent Good Example 2 Good Excellent Good Example 3 Good Excellent Good Example 4 Good Excellent Good Example 5 Good Excellent Good Example 6 Good Excellent Good Example 7 Good Excellent Good Example 8 Good Excellent Good Example 9 Good Excellent Good Example 10 Good Excellent Good Example 11 Good Excellent Good Example 12 Good Excellent Good Example 13 Good Excellent Good Example 14 Good Excellent Good Example 15 Good Excellent Good Example 16 Good Excellent Good Example 17 Good Excellent Good Example 18 Good Excellent Good Example 19 Good Excellent Good Example 20 Good Excellent Good Example 21 Good Excellent Good Example 22 Good Excellent Good Example 23 Good Excellent Good Example 24 Good Excellent Good Example 25 Good Excellent Good Example 26 Good Excellent Good Example 27 Good Excellent Good Example 28 Good Excellent Good Example 29 Good Excellent Good Example 30 Good Excellent Good Example 31 Good Excellent Good Comparative Good Ordinary Poor Example 1 Comparative Poor Poor Good Example 2 Comparative Poor Poor Poor Example 3 Comparative Good Good Poor Example 4 Comparative Good Good Poor Example 5 Comparative Good Good Poor Example 6 Comparative Good Good Poor Example 7 Comparative Good Good Poor Example 8 Comparative Poor Poor Poor Example 9 * Light exposure dose during production of liquid crystal alignment cell: 0.1 to 1.0 J/cm.sup.2

(111) As shown in Table 2, it was confirmed that since each of the liquid crystal alignment agent compositions of Examples 1 to 31 includes the polymer for the first liquid crystal alignment agent which is a partially imidized polyimide precursor along with the polymer for the second liquid crystal alignment agent which is a polyimide precursor derived from a diamine of the specific structure which does not form symmetry with respect to the center point or the center line, an excellent alignment property may be obtained without an initial thermosetting process, the AC afterimage-related luminance fluctuation rate was excellent at less than 10%, and the voltage holding ratio was also excellent at 70% or more under a high temperature environment, thereby exhibiting excellent effects in terms of electrical properties.

(112) In contrast, the liquid crystal alignment agent compositions of Comparative Examples 1 to 9 include neither of the polymer for the first liquid crystal alignment agent which is a partially imidized polyimide precursor or the polymer for the second liquid crystal alignment agent which is a polyimide precursor derived from a diamine of the specific structure which does not form symmetry with respect to the center point or the center line or include only the polymer composed of the single component of the diamines, and as a result, electrical properties or alignment properties of the liquid crystal cells were remarkably deteriorated.

(113) Particularly, in the case of Comparative Example 1, only the polymer for the first liquid crystal alignment agent which is a partially imidized polyimide precursor was used, and as a result, there was no problem in the alignment property of the liquid crystal alignment film, but the AC afterimage-related luminance fluctuation rate was 10% or more, and thus deterioration in the liquid crystal alignment stability was observed. In addition, the voltage holding ratio was less than 70%, which was evaluated as ‘poor’. In the case of Comparative Example 2, only the polymer for the second liquid crystal alignment agent which is a polyimide precursor derived from a diamine having an asymmetric pyridine structure was used. As a result, the voltage holding ratio was observed at the equivalent level or more, but there were problems in that light leakage such as a liquid crystal flow mark or a bright spot was observed in the evaluation of the alignment property of the liquid crystal alignment film, and thus it was evaluated as ‘poor’, and the luminance fluctuation rate of more than 20% was observed in the AC afterimage evaluation, and thus it was evaluated as ‘poor’. In the case of Comparative Example 3, the polymer for the second liquid crystal alignment agent which is a polyimide precursor derived from a diamine having an asymmetric pyridine structure was used, but para-phenylenediamine (p-PDA) was used instead of the partially imidized polyimide precursor as the first liquid crystal polymer, and as a result, all of the liquid crystal alignment property, stability, and voltage holding ratio were evaluated as ‘poor’.

(114) Furthermore, in the case of Comparative Examples 4 to 8, the polymer for the first liquid crystal alignment agent which is the partially imidized polyimide precursor was used, but the polymer prepared using para-phenylenediamine (p-PDA), oxydianiline (ODA), or methylenedianiline (MDA) was used instead of the diamine having the specific asymmetric structure which is the polymer for the second liquid crystal alignment agent, and as a result, there was no problem in the liquid crystal alignment property, but their voltage holding ratio was less than 70%, and thus they were evaluated as ‘poor’, indicating that there is a problem in terms of electrical properties. Further, in the case of Comparative Example 9, the polymer for the first liquid crystal alignment agent which is the partially imidized polyimide precursor was used, but the polymer prepared using 2,6-bis(trifluoromethyl)-4,4′-diaminodiphenyl ether was used as the polymer for the second liquid crystal alignment agent, and as a result, there were problems in that all of the liquid crystal alignment property, stability, and voltage holding ratio were evaluated as ‘poor’.