Monolayer contact film, designed, once made integral with a multilayer functional film, to constitute a final multilayer film of a pouch wall； the pouch having seams, and designed to be filled with biopharmaceutical product, and composed of a selected material that can be part of the composition of the final multilayer film, be in contact with the biopharmaceutical product, without degradation of the film and biopharmaceutical product, be sealable on itself, with a thickness that is less than the thickness of a single contact layer of the final multilayer film suitable for the production of seams of the single contact layer on itself, of which one surface functions as an interface for interlocking with a first interface for making the multilayer functional film integral, and whose other surface has as its final function to constitute the contact surface of the final multilayer film with the biopharmaceutical product.
