Both PE and PVC stretch films have certain moisture-proof properties, but there are differences in their effectiveness. PE stretch film has a tight molecular structure and good water vapor barrier properties, which can effectively prevent external moisture from entering the interior of the packaging. At room temperature, PE stretch film with moderate thickness can keep the contents of the packaging dry for a long time. For some electronic products, paper products, etc. that are sensitive to humidity, using PE stretch film for packaging can provide good moisture-proof protection. Moreover, the moisture-proof performance of PE film is relatively stable in different humidity environments, even in high humidity southern regions or humid storage environments, it can maintain a certain moisture-proof effect. However, PE stretch film is not completely waterproof, and infiltration may still occur even after prolonged immersion or exposure to a large amount of moisture.

PVC stretch film also has moisture resistance, and the chlorine atoms in its molecular structure provide a certain barrier to water vapor. However, compared to PE film, the moisture resistance of PVC film is greatly affected by temperature. At room temperature, PVC stretch film has a good moisture-proof effect and can be used to package products such as building materials and metal products that require moisture resistance, preventing them from getting damp, rusting, or deteriorating during storage and transportation. However, as the temperature increases, the components such as plasticizers in PVC film will change, causing the structure of the film to become loose, the water vapor barrier performance to decrease, and the moisture-proof effect to weaken. In addition, PVC film may experience aging during long-term use, and tiny cracks or holes may appear on the surface of the aged PVC film, further reducing its moisture resistance. Overall, the moisture-proof effect of stretch film can meet the moisture-proof needs of most ordinary items, but for special items with extremely high moisture-proof requirements, it may need to be combined with other moisture-proof measures.