Heat-seal Coating——A part that exists in blister packaging

Heat-seal Coating

Heat-seal coatings are used to bind the plastic blister pack and the lidding together. These coatings are molten or liquid polymer resins applied to the surface of the lidding material using techniques such as roll coating, knife coating, gravure, brushing, or spraying. The resin must be applied in the correct amount to ensure an air-tight seal. After application, the resin is allowed to dry on the foil's surface. Once the foil-seal coat film is used in packaging, the resin will be reactivated to form a secure bond.

Heat-seal coatings for blister packaging typically have several key characteristics: low-temperature activation, a low coefficient of friction, high gloss, and high transparency. For pharmaceutical and food packaging, the polymer resin must be approved by the FDA for direct food contact compliance. Common types of heat-seal coatings include solvent-based and water-based resins, such as polyvinylidene chloride (PVDC), acrylic, and ethylene acrylic acid (EAA). Additionally, extrusion-coated and co-extruded polyolefin films are used, including low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-vinyl acetate (EVA).