The multilayer film of claim 1, wherein a part of all of said recurring units (I) is units of the formula (II): ##STR4## wherein X, m and n are as defined above, and R1, R2, R3 and R4 are a monovalent group selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, phenyl group and a halogen atom.