Liquid crystal alignment agent, film and display element

A liquid crystal alignment agent, comprising:

• a polymer containing a repeating structural unit represented by the following formula (I):
• wherein each of P and Q is a divalent organic group;
• and
• an organic solvent for dissolving said polymer, wherein the liquid crystal alignment agent has a viscosity ranging from 8 to 35 cps at 25° C.,
• wherein said polymer is obtained by subjecting a diamine compound to polymerization in the presence of an acidic catalyst, and
• wherein said diamine compound is at least one selected from the group consisting of compounds represented by the following formulas (I-1) to (I-5) and (1) to (6):
• wherein
• R3 is a monovalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine;
• X is a divalent organic group;
• R4a and R4b are independently a divalent organic group having a ring structure containing a nitrogen atom selected from the group consisting of pyridine, pyrimidine, triazine, piperidine and piperazine;
• R5 and R7 are independently a divalent organic group selected from the group consisting of —O—, —COO—, —OCO—, —NHCO—, —CONH—, and —CO—;
• R6 is a monovalent organic group having a group selected from the group consisting of a steroid skeleton, a trifluoromethyl group, and a fluoro group, or an alkyl group having 6 to 30 carbon atoms;
• X1 and X2 are independently a divalent organic group selected from the group consisting of an alicyclic group, an aromatic group, and a heterocyclic group;
• R8 is selected from the group consisting of an alkyl group having 3 to 18 carbon atoms, an alkoxy group having 3 to 18 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, a fluoroalkoxy group having 1 to 5 carbon atoms, a cyano group, and halogen atoms;
• R9a, R9b, R9c, and R9d are independently a hydrocarbon group having 1 to 12 carbon atoms;
• p is an integer ranging from 1 to 3;
• q is an integer ranging from 1 to 20;
• and
• t is an integer ranging from 2 to 12.