Patent ID: 8871320

Claim:
A flexible tube skirt, made up by stacking an odd number of layers of plastic to form a film having a central layer and one or more pair/s of non-central symmetrical layers, wherein each pair of the non-central layers is disposed on either side of the central layer, and each pair of the non-central layers has the same rank, one layer in the centrifugal radial direction, the other in the centripetal radial direction, each pair of the non-central layers has substantially the same thickness and is substantially made from the same plastic material, in that each pair of the non-central layers consists of a polymer or a mixture of several polymers in identical proportions, said polymer(s) being produced from monomers with the same chemical composition and having substantially the same average molar mass, and wherein the average Young modulus of the plastic in the central layer is lower than the average Young modulus of the plastic in the non-central layers.