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. 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. It is not easy to heat-seal, 

which brings great difficulties to packaging. In order to solve this problem, people compound a layer of 

PVC film on the PET surface, named PETG hard sheet, but the price is higher.