Analysis of PE film characteristics

With the improvement of people's living standards in our country, the state forces residents to consume iodized salt, which puts forward corresponding requirements for the production and packaging of salt. Since the packaging bag of salt is food packaging, it has high hygienic requirements. Generally, non-toxic or low-toxic PE, PET, PP and PVC (composite film only for the outer layer) films are used. Polyethylene film, referred to as PE, is a thermoplastic polymer obtained by the polymerization of ethylene. It has excellent mechanical strength, dielectric properties and moisture resistance, and can maintain flexibility and chemical stability at low temperatures. Polyethylene film is colorless, tasteless, odorless, non-toxic and translucent. It does not react with moisture, grease, compounds, etc., is insoluble in most solvents at room temperature, and has poor thermal stability, but can withstand -70°low temperature of C. Good weldability, good permeability to oxygen and carbon dioxide, and poor permeability to water vapor. Polyethylene films can generally be divided into low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE) films. Untreated polyethylene film is a more difficult material to print. This is because polyethylene is non-polar, chemically stable, insoluble in most solvents, has a weak adsorption force on ink, and is not firm after drying. Therefore, the polyethylene film needs to be treated for printability before or during printing. The suitable printing treatment method for polyethylene film can usually be used to ionize the surface of the polyethylene film in an electric field or perform a short-term gas flame processing after the action of a strong oxidant (such as chlorine, ozone, potassium dichromate). The air permeability of PE film is relatively large, and its air permeability decreases with the increase of density. PE film has moisture resistance and low moisture permeability. Polyethylene film (PE) can produce low-density, medium-density, high-density polyethylene and cross-linked polyethylene and other products with different properties according to different manufacturing methods and control methods.