Composite film

A composite film having a layer structure of at least two layers, wherein a film layer (A) formed from a ring structure-containing polymer, which comprises a repeating unit derived from ring-opening polymerization of a monomer having a ring structure, carbon-carbon double bonds present in the main chain of which are saturated by hydrogenation, and in which a function group is introduced in a proportion of 1 to 30 mol % based on the repeating unit in the polymer, and a film layer (B) formed from a polycondensation polymer selected from the group consisting of polyether resin, thermoplastic polyester resin, polyamide resin and polyimide resin adjoin each other directly or through an adhesive layer.

A composite film having a layer structure of at least two layers, wherein a film layer (A) formed from a ring structure-containing polymer comprising a repeating unit derived from addition polymerization of a monomer having a ring structure, and a film layer (B) formed from a polycondensation polymer selected from the group consisting of polyether resin, thermoplastic polyester resin polyamide resin and polyimide resin adjoin each other directly or through an adhesive layer.