1. OPP film 

OPP film is a very important flexible packaging material. It is colorless, odorless and tasteless, and has high tensile strength, impact strength, rigidity, toughness and good transparency. The surface energy of OPP film is low, and corona treatment is required before gluing or printing. After corona treatment, OPP film has good printing adaptability, and can be overprinted to obtain exquisite appearance effects, so it is often used as the surface layer material of composite films. 

 

2. PET film 

PET film is also known as high temperature resistant polyester film. It has excellent physical properties, chemical properties and dimensional stability, transparency, and recyclability, and can be widely used in magnetic recording, photosensitive materials, electronics, electrical insulation, industrial films, packaging decoration, screen protection, optical mirrors surface protection and other fields. PET film is a kind of packaging film with comprehensive performance. It has good transparency and luster, good air tightness and fragrance retention, moderate moisture resistance, and the moisture permeability decreases at low temperatures. PET film has excellent mechanical properties, its strength and toughness are the best among all thermoplastics, its tensile strength and impact strength are much higher than ordinary films, and it has good stiffness and stable size, suitable for secondary processing such as printing and paper bags. PET film also has excellent heat resistance, cold resistance and good chemical resistance and oil resistance. However, it is not resistant to strong alkali and is easy to be charged with static electricity. There is no proper antistatic method, so attention should be paid when packaging powdery items.