Induction sealing is a contactless method of heating the inner plug for sealing plastic and glass vessels. This sealing method takes place after the closing of the cap-plug.
There are different types of wads; typical inductive wads consists of 4 layers. The upper layer is a paper pulp, which remains in the cap-plug of the packaging, the following layer is wax, which connects the layer of paper pulp and the aluminum foil, being the third layer. The bottom layer is a polymeric layer-laminated on the foil.
After closing the cap, the packaging passes through the induction process, where an oscillating electromagnetic field is emitted. The heat melts the wax, which is absorbed in the pulp base and releases the foil. The polymer film heats up and passes onto the bottleneck of the packaging. When cooled, the polymer creates a solid bond with the neck, leading to a hermetically sealed product.