Polymer Laminate Surface Energy and Foil Adhesion Dynamics
Foil adhesion succeeds when polymer film surface energy exceeds forty-two dynes per centimeter and sizing chemistry matches the polar surface component.
Carrier Release Coat
Release Performance
Functional release layers applied to temporary carrier films facilitate the clean transfer of decorative coatings to a target substrate. During the transfer process, the carrier release coat must maintain a precise balance between adhesion during storage and release during application. Incomplete transfers occur when the adhesion is too high, preventing the coating from separating.
Conversely, low adhesion leads to premature peeling during converting or rewinding. This release action is typically driven by low surface energy materials that do not form strong intermolecular bonds with the transferred lacquer.
Coating Formulation
Silicones or waxes are commonly used to create the low surface energy barrier. In high-speed gravure or flexographic printing, the carrier release coat is applied as a thin wet film and then cured. Crosslinking of the release polymers is necessary to prevent any transfer of the release chemistry itself onto the decorative lacquer, which would impair subsequent adhesion to the paperboard.
Production Boundary
Heat and pressure applied during transfer must exceed the softening point of the adhesive without degrading the release coat. Extreme tension during rewinding can also cause mechanical failure of the release layer. The carrier film must be recycled or discarded after the transfer step is complete.