Photoinitiator Migration Limits in Food Contact Print Finishes
Photoinitiator migration limits demand complete photopolymer conversion or functional containment to keep extractable residues below 10 parts per billion.
Metallized PET Barrier
Composite Barrier
High-performance packaging film consisting of a thin layer of vapor-deposited aluminum on a polyethylene terephthalate substrate provides excellent moisture and oxygen protection when laminated to paperboard. This composite material, referred to as a metallized pet barrier, blocks light and gases to extend the shelf life of sensitive products. It combines the mechanical strength of the paperboard with the barrier properties of metal.
This laminate is widely used in cosmetics and food cartons.
Barrier Performance
The microscopic metal layer blocks the transmission of water vapor and organic molecules through the paperboard matrix. Standard tests measure the water vapor transmission rate to quantify this resistance. Because the metal is deposited on a stable polyester film, the barrier remains consistent even under high humidity.
This stability prevents the paperboard from absorbing moisture and losing its structural stiffness.
Lamination Quality
Converting paperboard with this laminated film requires careful adjustments to the creasing and die-cutting parameters to prevent delamination of the layers. If the adhesive bond between the paperboard and the polyester film is weak, the film can peel away during the high-speed folding process. This delamination would ruin the appearance of the carton and compromise the barrier.
To prevent this, converters monitor the surface tension of the film and use specialized water-based adhesives. Testing the finished cartons for seal strength and fiber tear ensures that the package will perform reliably on the filling line.