Provided is a polyurea copolymer having a structure represented by formula (1). In formula (1), R1 represents an alkyl group that has 1-4 carbon atoms and that may be branched, and R2 represents a hydrogen atom, an aliphatic hydrocarbon group having 1-4 carbon atoms, or an organic group represented by formula (1-1). Ra and Rb each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 or 2 carbon atoms. X represents a divalent organic group represented by formula (S), and Y represents a divalent organic group. The black dots in formula (S) represent a point of bonding to a nitrogen atom, and R1, Ra, and Rb have the same meaning as explained above regarding formula (1). Q1 and Q2 in formula (S) are a structure represented by formula (Q1-1), a structure represented by formula (Q1-2), or a single bond. At least one of Q1 and Q2 is the structure represented by (Q1-1) or the structure represented by (Q1-2). q1 and q2 each independently represent 0 or 1, and L1 and L2 represent a hydrogen atom. When Q1 is the structure represented by formula (Q1-1), L1 and L2 may be combined and form a single bond. The black dots represent a point of bonding to a nitrogen atom. R5 in formula (Q1-1) represents a hydrogen atom, a t-butoxycarbonyl group, or an alkyl group having 1-6 carbon atoms. When R5 represents an alkyl group having 1-6 carbon atoms, R5 may be branched, form a ring, or have an unsaturated bond. E represents –NH-, -NMe-, -S-, or –O-, and F and G each independently represent CH or a nitrogen atom.
POLYUREA COPOLYMER, LIQUID CRYSTAL ALIGNMENT AGENT, LIQUID CRYSTAL ALIGNMENT FILM, AND LIQUID CRYSTAL DISPLAY ELEMENT USING SAME