Polyester/primer/metal composite film that is cohesive and impermeable to gas, method for the production thereof and the primer utilized in said method

Abstract

The aim of the invention is to provide polyester/primer/metallic coating composite films having good adherence of the metallic coating in dry and humid conditions. Said films also form a good gas barrier: oxygen permeability less than or equal to 0.8 cc/m2/d; water vapour permeability less than or equal to 0.3 g/m2/d. To this end, the invention concerns a composite film comprising a polyester substrate, at least one coating adhering on at least one of the faces of the substrate and at least one layer of primer for cross-linked adhesion between the substrate and the coating. Said primer comprises at least one acrylic and/or methacrylic polymer P1, at least one acrylic and/or methacrylic polymer P2 different from P1, at least one cross-linking agent, and, preferably, at least one polyester that is soluble or dispersible in water: —P1 having a gel content TG1>70% by dry weight with respect to P1; —P2 having a gel content TG2≤TG1 and ≤20% by dry weight, with respect to P2; —P1 having a surface-grafted free weak acid content≥0.8 in meq/g of polymer; —[P2]≤60% by weight on dry by weight in respect to P1+P2. The method for producing said film, the adhering primer, and the articles obtained using said film, also form part of the present invention.

Dependencies are inferred from the claim text.