A multi-layered structure comprising an induction activation layer comprising a blend of (a) a first thermoplastic polymer, (b) a plurality of first particles, each said first particle comprising (i) a core comprising one or more magnetic materials and (ii) a shell comprising silicon dioxide; and (c) optionally a plurality of second particles, each said second particle comprising heat conducting particles; and a sealant, wherein the sealant exhibits a melting point equal to or lower than any other layer in the multi-layered structure, wherein the induction activation layer and sealant are in direct or indirect thermal contact is provided.