Conventional PET is a crystalline polymer; after biaxial stretching and orientation, PET film exhibits significant crystallinity. If subjected to heat sealing, it will undergo shrinkage and deformation, which is why standard PET film lacks heat-sealability. When used for product packaging, to address the issue of heat-sealable edges, BOPET film is typically laminated with PE or CPP film, thereby somewhat limiting the application scope of BOPET film.
　　To address the heat-sealing issue, PET resin has been modified and a three-layer A/B/C die has been employed, resulting in the development of a three‑layer co‑extruded heat‑sealable PET film. Because one side of this film is a heat‑sealable layer, it can be directly heat‑sealed, making it highly convenient to use.
　　Heat-sealable PET film is widely used in packaging for various products and as card‑protective films, among other applications.