In Formula (IV), each of R11, R12 and R13 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkanol group having 1 to 8 carbon atoms, an alkanediol group having 1 to 8 carbon atoms, an alkanetriol group having 1 to 8 carbon atoms or a group represented by ???(R14O)cR15.