Do industrial grade OPP plastic bags have good moisture-proof properties?

Although industrial-grade OPP plastic bags are widely used in the packaging industry, their moisture-proof performance is relatively limited. OPP material itself is a semi-crystalline structure. Although it has a certain degree of rigidity and transparency, its molecular structure does not completely block the penetration of moisture, so it cannot completely prevent the entry of moisture. This makes its application in humid environments have certain limitations, especially for those items that are sensitive to moisture, such as food, electronic products or pharmaceutical products, etc., the use of OPP plastic bags may not provide sufficient protection.
In order to make up for this defect, there are some methods in modern industrial production to improve the moisture-proof function of OPP plastic bags. For example, by coating the surface of OPP film, its barrier effect against moisture can be enhanced. The common practice is to coat a layer of film to increase its moisture-proof performance, or to combine OPP film with other materials with more moisture-proof performance, such as polyethylene (PE) or aluminum foil film, through composite material technology. This multi-layer composite structure can significantly improve the moisture-proof performance of the bag and slow down the penetration of water vapor.
The sealing technology of OPP plastic bags can also affect its moisture-proof performance to a certain extent. Efficient heat sealing technology can ensure the sealing of the bag mouth, thereby reducing the entry of water vapor. Especially in some high humidity environments, the sealing of the bag mouth is crucial because it is the weak link of moisture-proof. If the seal is not tight, even if the main part of the bag has good moisture-proof properties, it may still cause moisture to the internal items.
The moisture-proof property of OPP plastic bags is also affected by their thickness. Thicker OPP bags can provide better protection to a certain extent compared to film bags. However, increased thickness means increased costs and increased material usage, so when choosing OPP plastic bags, it is necessary to weigh the balance between moisture-proof needs and economic costs.
For some specific packaging needs, a single OPP plastic bag may not be sufficient to meet strict moisture-proof requirements. For long-term storage needs in high humidity environments, OPP plastic bags can be considered in combination with other moisture-proof materials. For example, adding desiccant to OPP plastic bags or using airtight and moisture-proof packaging bags, such as aluminum foil bags, PE bags, etc., can further enhance the moisture-proof effect.