Induction cap sealing systems guarantee long-lasting product freshness. Induction cap sealers extend shelf life, reduce packaging weight, and ensure that complaints about leakages are a thing of the past. This non-contact process provides hermetic seals for bottles, jars and other container types.
Containers with caps lined with an inner seal are exposed to a controlled electro-magnetic field generated by an induction coil. When the foil layer of the inner seal enters the electro-magnetic field a current is induced into the foil causing it to heat up. The heating of this layer activates a polymer or adhesive coating on the sealing surface. The cap’s applied torque is used to maintain pressure and contact between the sealing surface and the container rim so that when the liner cools the result is a hermetically sealed container.
The structure of the inner seal can be a simple laminate consisting of EPE (Expanded Polyethylene), aluminum foil, PET (Polyethylene Terephthalate) and a polymer / adhesive layer or even more complex structures which include additional supporting layers of paper or foam bonded to the induction seal by a wax layer designed to melt and be absorbed during the heating process. Inner seals may also be printed on with a manufacturer’s logo, opening instructions or further advertising options. Because a foil seal is strong and flexible it can be used as a form of tamper evidence, as a broken inner seal can be designed to leave a residue that is easily detectable on the container rim.
Hand held and portable induction sealers can be used in labs for trials or for small production runs. High speed induction cap sealers are positioned over a conveyor and use sealing heads optimised for the container and cap configuration they are sealing.
This technology may also be used to seal containers without caps or caps without the required torque. Capless sealing systems use a pressure-belt or other means to secure the liner during the sealing process.