The blister packaging sheet is called hard sheet or film. Commonly used are: PET (polyethylene 

terephthalate) hard sheet, PVC (polyvinyl chloride) hard sheet, PS (polystyrene) hard sheet. PS rigid 

sheet has low density, poor toughness, easy to burn, and will produce styrene gas (a harmful gas) 

when burning, so it is generally used to produce various industrial plastic trays. The rigid PVC sheet 

has moderate toughness and is not easy to burn. Chlorine gas will be generated during combustion, 

which will have a certain impact on the environment. PVC is easy to heat-seal. It can be sealed with 

a sealing machine and high-frequency machine. It is the main raw material for the production of 

transparent plastic products. PET rigid film has good toughness, high transparency, easy to burn, 

and does not generate harmful gases during combustion. It is an environmentally friendly material, 

but it is expensive and suitable for high-grade plastic products. Plastic blister shells in Europe and 

the United States generally require PET hard films, but It is not easy to heat-seal, which brings great difficulties to packaging. In order to solve this problem, people use a material called PETG ethylene 

glycol modified-polyethylene terephthalate. This material has the advantages of PVC. Heat-sealing, 

PET also has high environmental protection and transparency, but the price is higher.