The seal (Insert, Liner or Wad) material is inserted into the cap (closure or lid). In the case of chemicals, it is important to prevent leaks through the cap. For containers which are expected to be opened and closed more than once it is important that the seal material can offer an air tight cap fitting when the cap is screwed back onto the container.
When oil bottles are transported they can be subject to stressful transport conditions. The use of an Induction Heat Seal can provide a “true weld” of a foil material to the top of the bottle neck. With this Foil welded into place, the Oil bottle can withstand large stresses without leaking.
Other types of seals can provide an aroma and vapour tight cap fitting onto the bottle. These seals can be provided with foils resistant to alkali and acids as well as to animal and vegetable fats and oils. These seals have a base of Board or Foam. (Board is used for screw cap lids and Foam is used for both screw and snap cap lids)