The sheet used for blister packaging is called hard sheet or film. Commonly used are PET (polyethylene terephthalate) hard sheets, PVC (polyvinyl chloride) hard sheets, and PS (polystyrene) hard sheets. PS hard film is low in density, poor in toughness, easy to burn, and generates styrene gas (which is a harmful gas) when it is burned, so it is generally used to produce various industrial plastic trays.

PVC hard sheet has moderate toughness, is not easy to burn, and generates chlorine when it is burned, which has a certain impact on the environment. PVC is easy to heat and can be sealed by a sealing machine and high-frequency machine. It is the main raw material for producing transparent plastic products.

PET hard film has good toughness, high transparency, easy to burn, no harmful gas when burning, and belongs to environmental protection material, but its price is high and it is suitable for high-grade plastic products