Liquid crystal aligning agent composition, method for preparing liquid crystal alignment film using same, and liquid crystal alignment film using same

1. A liquid crystal aligning agent composition comprising:

a polymer including a repeating unit represented by the following Chemical Formula 1, or a repeating unit represented by the following Chemical Formula 2; and

a polycarbodiimide compound represented by the following Chemical Formula 5:

wherein, in Chemical Formulas 1 and 2,

at least one of R 1 and R 2 is an alkyl group having 1 to 10 carbon atoms and the other is hydrogen,

X 1 and X 2 are each a tetravalent organic group represented by the following Chemical Formula 3,

wherein, in Chemical Formula 3,

R 3 to R 8 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,

L 1 is any one selected from a single bond, —O—, —CO—, —COO—, —S—, —SO—, —SO 2 —, —CR 9 R 10 —, —(CH 2 ) Z —, —O(CH 2 ) Z O—, —COO(CH 2 ) Z OCO—, —CONH—, phenylene, or a combination thereof,

where R 9 and R 10 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a fluoroalkyl group,

Z is an integer of 1 to 10,

Y 1 and Y 2 are each independently a divalent organic group represented by the following Chemical Formula 4,

wherein, in Chemical Formula 4,

at least one of Q 1 to Q 4 is a nitrogen atom and each of the rest is a carbon atom,

R 3 is hydrogen or an alkyl group having 1 to 6 carbon atoms,

wherein, in Chemical Formula 5,

A is an organic group including —O—, —CO—, —S—, —C(CH 3 ) 2 —, —C(CF 3 ) 2 —, —CONH—, —COO—, —(CH 2 ) b —, —O(CH 2 ) b O—, —COO—(CH 2 ) b —OCO—, a urethane-based functional group or a urea-based functional group,

b is an integer of 1 to 10,

R 11 is an alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms,

m is an integer of 1 to 5,

D is a functional group represented by the following Chemical Formula 6,

wherein, in Chemical Formula 6,

T is —O— or —NH—,

R 12 is hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an ether group, and when T is oxygen R 12 is not a halogen, and

R 13 is hydrogen or an alkyl group having 1 to 6 carbon atoms.

2. The liquid crystal aligning agent composition of claim 1 , wherein in the functional group represented by Chemical Formula 6, T is —O—, R 12 is an ether group of the following Chemical Formula 6-1, and R 13 is hydrogen,

wherein, in Chemical Formula 6-1, R 10 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R 15 is an alkylene group having 1 to 6 carbon atoms, and p is an integer of 1 or more.

3. The liquid crystal aligning agent composition of claim 1 , wherein in the functional group represented by Chemical Formula 6, T is —NH—, R 12 is hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R 13 is hydrogen.

4. The liquid crystal aligning agent composition of claim 1 , wherein the polycarbodiimide compound represented by Chemical Formula 5 is contained in an amount of 0.5 wt % to 15 wt % based on the total weight of the liquid crystal aligning agent composition.

5. The liquid crystal aligning agent composition of claim 1 , wherein the polymer further includes a repeating unit represented by the following Chemical Formula 7 or 8:

wherein, in Chemical Formula 7 and 8, X is X 1 or X 2 as defined in claim 1 ,

Y is Y 1 or Y 2 as defined in claim 1 ,

R 30 is hydrogen or an alkyl group having 1 to 10 carbon atoms, and

D is as defined in claim 1 .

6. The liquid crystal aligning agent composition of claim 5 , wherein the repeating unit represented by Chemical Formula 7 or 8 is contained in an amount of 0.1 mol % to 20 mol % based on the mole number of the repeating unit represented by Chemical Formula 1 or 2.

7. The liquid crystal aligning agent composition of claim 1 , wherein in Q 1 to Q 4 of Chemical Formula 4,

one of Q 2 and Q 4 is nitrogen and the other is carbon, and

Q 1 and Q 3 are carbon.

8. The liquid crystal aligning agent composition of claim 1 , wherein in Q 1 to Q 4 of Chemical Formula 4,

Q 2 is nitrogen, and

Q 1 , Q 3 , and Q 4 are carbon.

9. The liquid crystal aligning agent composition of claim 1 , wherein in Chemical Formula 4, R 3 is hydrogen.

10. The liquid crystal aligning agent composition of claim 1 , wherein Chemical Formula 4 includes functional groups represented by the following Chemical Formulas 4-1 to 4-3:

wherein, in Chemical Formulas 4-1 to 4-3, Q 1 to Q 4 and R 3 are as defined in claim 1 .

11. A method for preparing a liquid crystal alignment film comprising the steps of:

coating the liquid crystal aligning agent composition of claim 1 onto a substrate to form a coating film;

drying the coating film;

irradiating the coating film immediately after drying with light or rubbing the coating film to obtain an alignment-treated coating film; and

heat-treating and curing the alignment-treated coating film.

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

13. The method for preparing a liquid crystal alignment film of claim 11 , wherein the step of drying the coating film is performed at 50° C. to 150° C.

14. The method for preparing a liquid crystal alignment film of claim 11 , 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.

15. The method for preparing a liquid crystal alignment film of claim 11 , wherein in the step of curing the coating film, the heat treatment temperature is 150° C. to 300° C.

16. A liquid crystal alignment film comprising an aligned cured product of the liquid crystal aligning agent composition of claim 1 .

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

18. The liquid crystal aligning agent composition of claim 1 , wherein, in Chemical Formula 5, the functional group represented by A is a functional group represented by the following Chemical Formula 21 or a functional group represented by the following Chemical Formula 22:

—R′-G 1   [Chemical Formula 21]

in Chemical Formula 21, R′ is a divalent organic functional group, and G 1 is a functional group of the following Chemical Formula 6 in which T is —O—, R 12 is an ether group of the following Chemical Formula 6-1, and R 13 is hydrogen,

in Chemical Formula 6-1, R 14 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R 15 is an alkylene group having 1 to 6 carbon atoms, and p is an integer of 1 to 5,

in Chemical Formula 22, R″ is a trivalent organic functional group, and G 2 is a functional group of the following Chemical Formula 6 in which T is —O—, R 12 is an ether group of the following Chemical Formula 6-1, and R 13 is hydrogen,

in Chemical Formula 6-1, R 14 is hydrogen or an alkyl group having 1 to 6 carbon atoms, R 15 is an alkylene group having 1 to 6 carbon atoms, and p is an integer of 1 to 5,

G 3 is a functional group of the Chemical Formula 6 in which T is —NH—, R 12 is hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R 13 is hydrogen.