Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element having thereof

A liquid crystal alignment agent, comprising:

• a polymer composition (A), obtained by reacting a mixture that includes a tetracarboxylic dianhydride component (a) and a diamine component (b), wherein the diamine components (b) contains at least one diamine compound having carboxyl group (b-1) and an other diamine compound (b-2);
• the photopolymerizable compound (B) having a structure of Formula (I):
• In the Formula (I), R1 independently is a polymerizable functional group having structures of Formulas (I-1) to (I-5), a hydrogen atom, a halogen atom, —CN, —CF3, —CF2H, —CFH2, —OCF3, —OCF2H, —N═C═O, —N═C═S or an alkyl group of 1 to 20 carbons, wherein any —CH2— is optionally replaced by —O—, —S—, —SO2—, —CO—, —COO—, —OCO—, —CH═CH—, —CF═CF— or —C≡C—, and any hydrogen atom is optionally replaced by a halogen atom or —CN;
• Y independently is a divalent group containing a saturated or an unsaturated separated ring, a condensed ring or a spiro ring of 3 to 20 carbons, wherein any —CH2— is optionally replaced by —O—, any —CH═ is optionally replaced by —N═, and any —H is optionally replaced by a halogen atom, —CN, —NO2, —NC, —N═C═O, —N═C═S, a silyl group, a straight-chain alkyl group of 1 to 10 carbons, a branched-chain alkyl group of 1 to 10 carbons, or a haloalkyl group of 1 to 10 carbons, wherein —CH2— in the alkyl group is optionally replaced by —O—, —CO—, —COO—, —OCO—, —OCOO—, —CH═CH— or —C≡C—;
• Z is an alkylene group of 1 to 20 carbons, wherein —CH2— is optionally replaced by —O—, —S—, —SO2—, —CO—, —COO—, —OCO—, —OCOO—, —CH═CH—, —CF═CF—, —CH═N—, —N═CH—, —N═N—, —N(O)═N— or —C≡C—, and any —H is optionally replaced by a halogen atom, an alkyl group of 1 to 10 carbons or a haloalkyl group of 1 to 10 carbons;
• m is an integer of 1 to 6, and when m is an integer of 2 to 6, the plural —Y—Z— can be the same or different.
• In the Formulas (I-1) to (I-5), R2 is a hydrogen atom, a halogen atom, —CF3 or an alkyl group of 1 to 5 carbons;
• and
• a solvent (C).