Canning and Fish Packaging Technology

Unit 10 - Manufacture of plastic packages

10.1.2.5.Vacuum metalizing
Plastics such as PP, PET (usually oriented) are coated on one side and sometimes on both sides with a very thin layer of metal usually aluminium. The metalizing operation takes place completely in a very low pressure vacuum chamber, molten aluminium is heated and under low pressure vaporizes and condenses on to moving web of the film as a thin continuous layer.
By this method the plastic gets an attractive metallic appearance and also improves barrier properties towards gases, water vapour and flavours.