The metallization of a BOPP film is a process that allows the deposit of a thin layer of metal (about 200 Å) on the film surface through the condensation of vapours
This process doesn't alter the original properties of the materials. It increases the opacity to light and to UV radiations, as well as improves the barrier properties to oxygen and water vapour, and gives the film a glossy and reflecting appearance. Thus considerably enhancing the aesthetic effect and the outcome of the packaging presentation.
The metallization process takes place in semi-continuous machinery and consists of alternating "cycles" of pure metallization (vacuum) with cycles of simple and methodical preparation (in air) of the machine for the following working phase.
The Aluminium, under ultra vacuum conditions (vacuum level required: ~ < 4 x 10-4 mbar), is brought to vapor state inside the machine in crucibles usually composed of Boron Nitride (BN) and Borides of Titanium (TiB2), that reach 1500 °C temperature.