Copolymer for liquid crystal alignment agent, liquid crystal alignment agent including the same, and liquid crystal alignment film and liquid crystal display device using the same

A copolymer for a liquid crystal alignment agent comprising:

• one 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;
• and
• 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:
• wherein, in the Chemical Formulae 1 to 6,
• R1, R2, R3, and R4 are each independently hydrogen or a C1-10 alkyl, provided that R1 and R2 are not both hydrogen, and that R3 and R4 are not both hydrogen,
• X1, X3, and X5 are each independently a tetravalent organic group represented by Chemical Formula 7:
• wherein, in the Chemical Formula 7,
• R5, R6, R7, and R8 are each independently hydrogen or a C1-6 alkyl,
• X2, X4, X6, X7, X8, and X9 are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms or a tetravalent organic group, wherein in the tetravalent organic group, one or more of H is substituted with a halogen or one or more of —CH2— is substituted with —O—, —CO—, —S—, —SO—, —SO2—, or —CONH— to prevent direct binding with oxygen or sulfur atoms,
• in Chemical Formulae 1 to 3,
• Y1, Y2, Y3, Y4, Y5, and Y6 are each independently a divalent organic group represented by Chemical Formula 8:
• wherein, in the Chemical Formula 8,
• R9 and R10 are each independently a halogen, a cyano, a C1-10 alkyl, a C2-10 alkenyl, a C1-10 alkoxy, a C1-10 fluoroalkyl, or a C1-10 fluoroalkoxy,
• p and q are each independently an integer of 0 to 4,
• L1 is a single bond, —O—, —CO—, —S—, —SO2—, —C(CH3)2—, —C(CF3)2—, —CONH—, —COO—, —(CH2)z—, —O(CH2)zO—, —O(CH2)z—, —OCH2—C(CH3)2—CH2O—, —COO—(CH2)z—OCO—, or —OCO—(CH2)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, wherein when n=0, k is 1 to 3, and wherein when k=0, m and n are each independently 1 to 3,
• in the Chemical Formulae 4 to 6,
• Z1, Z2, and Z3 are each independently a divalent organic group represented by Chemical Formula 9:
• wherein, in the Chemical Formula 9,
• A1 is oxygen, sulfur, selenium, tellurium or polonium,
• R11 is hydrogen or a C1-10 alkyl,
• a is an integer of 0, and
• A2, A3, A4, and A5 are nitrogen or carbon, provided that at least one of A2 to A5 is nitrogen and the rest are carbon.