Patent ID: 8469594

Claim:
A closure strip for a bag, comprising two supporting webs provided, on their internal surfaces facing each other and at a distance from their longitudinal edges, with at least one longitudinal closure assembly, each supporting web comprising: an upper portion, extending longitudinally in an upper portion of the supporting web, and a lower portion, extending longitudinally in a lower portion of the supporting web, underlying the upper portion, wherein, for at least one of the webs, the internal faces, which correspond to the faces of the upper and lower portions which are facing each other, are made of materials having different melting temperatures, the melting temperature of the constitutive material of the internal face of the upper portion being less than the melting temperature of the constitutive material of the internal face of the lower portion, wherein the closure strip further comprises a line of weakening which extends longitudinally in an intermediate area of each web extending between the upper portions and the closure assembly, and said intermediate area of each web is made of a third material so that said intermediate areas have a lower tensile strength than the upper and lower portions.