Finishing Process
Application of a thin plastic film to the surface of a printed substrate enhances the appearance and durability of the final product. During print lamination, heat and pressure are used to bond a layer of biaxially oriented polypropylene or polyester to paper or board. This process creates a protective barrier that resists moisture and physical abrasion.
Visual appeal increases. It is commonly used for book covers and items that require a high gloss or matte finish.
Bonding Method
Different adhesive systems determine the speed and environmental impact of the converting operation. Solvent based adhesives were historically common, but water based and solvent free thermal systems have become the standard for print lamination in many regions. Thermal lamination uses a film that is pre coated with a heat activated resin, which eliminates the need for liquid adhesive application on the press.
This method provides a clean bond and allows for immediate further processing such as die cutting or folding.
Surface Interaction
Successful adhesion depends on the surface energy of the printed ink and the type of laminate film selected. If the ink contains high levels of wax or silicone, the print lamination bond may fail and cause the film to tunnel or peel away. Proper surface treatment of the film is also necessary to ensure that it can be glued or foiled during later stages of production.
Testing the bond strength with a peel test ensures that the laminate will survive the mechanical stresses of the supply chain. Furthermore, the thickness of the film must be balanced against the rigidity of the substrate to prevent curling or warping of the finished piece.
