Patent ID: 8720729

Claim:
A peel-seal foil for providing a valve of a food package, the foil having an outer edge and comprising: a first plastic film, and a second plastic film, and an adhesive layer interposed between the first plastic film and the second plastic film and disposed inwardly of said outer edge, and which laminates together the first and second plastic films, wherein the first plastic film has a first side and a second side and comprises punctures therebetween, said punctures being disposed between said outer edge and said adhesive layer, wherein the first plastic film realizes at its first side a first peel-able seal at said outer edge, wherein in its sealed state the first peel-able seal is sensitive to gas-pressure that is built up by gas that entered into the foil between the first and second plastic films through the punctures, such that the first peel-able seal is peeled-off if said gas-pressure exceeds a threshold and the gas can depart from the foil by passing along in-between the two films, and the first plastic film further realizes a second peel-able seal at its second side when sealed together with a structure, the second peel-able seal being non-sensitive to said gas-pressure, and wherein the adhesive layer leaves open the punctures such that gas can penetrate through the punctures in-between the two films and can pass towards the first peel-able seal, forming an outlet valve portion located at the outer edge of the foil.