Thermo-seals were produced using an impulse-wire thermo-sealer. This sealing technique was chosen over impulse bar since the first one allows cooling the seal before the jaws are opened,
enhancing thereby its strength (López et al., 2011). Besides, it is the most used technique for flexible synthetic materials and consists in heating a film sample up to its fusion temperature by a short
powerful electric impulse. Thermo-sealing resistance was evaluated in an Instron 3369 universal machine (Instron, USA) by tensile