Patent ID: 6878229

Claim:
A process for the production of a composite film for packaging purposes with good permeability barrier effect for water vapor and other gases after sterilization in a water bath or in water vapor at a temperature of more than 90° C., where the composite film also has as a substantial constituent a barrier layer with SiO x produced by the vaporization of inorganic materials, the composite film comprises a film of polyethylene terephthalate (PET) with a coextruded layer of polyethylene-2,6-naphthalate (PEN) on at least one side and the film on at least one of the PEN-coated sides has a 10 nm to 200 nm thick ceramic layer of SiO x , where x is a number between 0.9 and 1.2, comprising depositing on a film of polyethylene terephthalate (PET) coated on at least one side with polyethylene-2,6-naphthalate (PEN), on at least one of the PEN-coated sides, a ceramic layer of SiO x , where x is a number between 0.9 and 1.2, by means of the thin-film vacuum process through the simultaneous vaporization of silicon dioxide (SiO 2 ) and metallic silicon together as a mixture, wherein to the materials to be vaporized are added further additives in quantities of up to 50 mol percent, always in relation to SiO 2 , and subsequently laminating the film coated with the ceramic layer with at least one further film on at least one of the SiO x coated PET layers to form the composite film.