Patent ID: 11370933

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.