Liquid crystal alignment agents, liquid crystal alignment films, liquid crystal display elements and novel monomers

Abstract

The present invention provides a liquid crystal alignment film that exhibits minimal change in pretilt angle and excellent display reliability even after prolonged driving, a liquid crystal display element having the same, and a liquid crystal alignment agent thereof. The present invention provides a liquid crystal alignment agent, characterized in that it contains a polymer having a photoalignment group as shown in the following formula (pa-1) as component (A) and a solvent; (In the formula, A represents pyrimidin-2,5-diyl, pyridin-2,5-diyl, 2,5-thiophene, 2,5-furan, 1,4- or 2,6-naphthylene, or phenylene, which are substituted by a group selected from fluorine, chlorine, or cyano, or by an alkoxy group having 1 to 5 carbon atoms, a straight-chain or branched-chain alkyl residue (which is substituted by one or more halogen atoms, depending on the case). R1 ​​represents a single bond, an oxygen atom, or a -COO- group.) Or -OCO-, R2 represents a divalent aromatic group, a divalent alicyclic group, a divalent heterocyclic group, or a divalent condensed cyclic group, R3 represents -COO- or -OCO-, R4 represents a monovalent organic group containing a straight-chain or branched alkyl or alicyclic group with 3 to 40 carbons, D represents an oxygen atom, a sulfur atom, or -NRd- (where Rd represents a hydrogen atom or an alkyl group with 1 to 3 carbons), a represents an integer from 0 to 3, and * represents the bond position).