The aluminum coating film (metallised film) is obtained by evaporating a high-purity aluminum wire into a gaseous state at a high temperature (1100 to 1200℃) by a vacuum aluminum plating process. After the plastic film passes through a vacuum evaporation chamber, gaseous aluminum molecules are precipitated on the surface of the plastic film to form a bright light metallic color.
Aluminum metallized film is a composite flexible packaging material formed by coating a thin layer of aluminum on the surface of plastic film by a special process. The most common processing method is vacuum aluminum plating, which melting and evaporating metal aluminum by high temperature under high vacuum, make the aluminum vapor depositing onto the surface of the plastic film to get a metallic luster.
As it has the characteristics of plastic film and metal either, it is a cheap , excellent performance and practical packaging material.
The aluminum coating process of plastic film is generally carried out by direct coating, which is, the aluminum layer is directly plated on the surface of the substrate film. BOPET and BOPA film substrates do not need to be surface treated before aluminum plating, and can be directly evaporated. For non-polar plastic films such as BOPP, CPP, PE, etc., the surface of the film needs to be corona treated or coated with an adhesive layer to achieve a surface tension of 38-42 dynes/cm or good adhesion.
At the time of vapor deposition, the roll film was placed in a vacuum chamber which was closed to evacuate.
When the degree of vacuum reaches a certain level (4×10-4 mba or more), the evaporation boat is heated to 1300 to 1400℃, and then the aluminum wire with a purity of 99.9% is continuously sent to the evaporation boat.
Aluminum metallized film production process:
Substrate unwinding → vacuuming → heating evaporation boat → sending aluminum wire → evaporation → cooling → thickness measurement → flattening → winding