Synthetic replacement for pulpboard in waxbond innerseals

摘要

An innerseal is provided for sealing against the lip of a container opening under a cap. The innerseal includes a resiliently-compressible porous synthetic backing layer which fits within the cap, a foil layer, and a wax layer which initially holds the foil and backing layers together. Preferably, a heat-activatable adhesive layer is disposed against the foil layer. The cap is tightened so that the foil layer is pressed against the lip of the container opening. Then, heat is applied to melt the wax and to activate the adhesive layer. This molten wax is absorbed into the synthetic backing layer so that the backing layer and foil layer are separatable by a twisting of the cap. The synthetic backing layer provides improved strength and liquid resistance characteristics over pulpboard type seals, and is cuttable with less dust.