A foil-based material sealed to the formed blister web to close filled cavities.
Also called: lidding material; lid foil; blister lid.
Lidding layers and their functions
A foil-based lid can include a print-side primer, an aluminium support and a heat-seal layer on the joining side. These layers perform different roles, so aluminium thickness alone does not fully describe the lidding construction.
Specify the print side, sealing side and intended forming web. Heat-seal layer chemistry and foil thickness describe different parts of the construction; the selected joining surfaces must be compatible.
No. Aluminium push-through lids and paper/aluminium or paper/PET/aluminium peel-off push-through constructions have different opening arrangements. Specify the intended opening action rather than inferring it from the presence of aluminium.
The exact lidding grade needs to match the intended base-web sealing surface. A material family covering several substrates does not make every version interchangeable. Retain the lid/base pairing, opening requirement and relevant trial evidence; a successful bond alone does not define how the user opens the pack.