Does packaging bag achieve excellent moisture-proof performance through special materials or processes?
Publish Time: 2024-12-10
In the field of packaging, moisture-proof performance is one of the key indicators to measure the quality of packaging bags, and modern packaging bags have successfully created excellent moisture-proof effects through the perfect combination of special materials and exquisite craftsmanship.
Special materials have laid a solid foundation for the moisture-proof performance of packaging bags. Materials such as polyvinylidene chloride (PVDC) have extremely low water vapor permeability, and their molecular structure is tight, which can effectively block the penetration of water molecules. Packaging bags coated with PVDC are like putting a layer of waterproof "armor" on the items in the bag, which can keep the inside dry even if placed in a humid environment for a long time. Another common composite material is EVOH (ethylene-vinyl alcohol copolymer). EVOH has excellent barrier properties to oxygen and water vapor. It can play a key role in moisture-proof and air-proofing in multi-layer structures, and cooperate with other materials such as polyethylene and polypropylene to form a powerful moisture-proof system. For example, in food packaging, the use of packaging bags made of this composite material can greatly extend the shelf life of food and prevent problems such as mildew and deterioration caused by moisture.
In terms of technology, multi-layer co-extrusion technology can be said to be a major "contributor" to moisture-proofing. By extruding and compounding plastic materials with different characteristics in an extruder at one time, each layer of material complements each other and is tightly combined. This process can accurately control the thickness and uniformity of each layer, avoiding interlayer peeling or gaps that may occur in traditional composite processes, making it impossible for water vapor to "start". For example, when producing pharmaceutical packaging bags with high moisture-proof requirements, the multi-layer co-extrusion process can accurately sandwich the EVOH layer with high barrier properties in the middle, the outer layer uses a wear-resistant and puncture-resistant polyethylene layer, and the inner layer is a smooth polypropylene layer. This structural design is both moisture-proof and adaptable to various complex packaging environments.
In addition, the vacuum aluminum plating process also adds a lot to the moisture-proof performance of packaging bags. In a high vacuum environment, aluminum is evaporated and deposited on the surface of the plastic film to form an extremely thin aluminum layer. This layer of aluminum can not only reflect light and prevent ultraviolet rays from damaging items, but also greatly improve the moisture-proof performance of packaging bags. The water vapor transmission rate of packaging bags after aluminum plating is greatly reduced. For the packaging of some electronic products and cosmetics that are sensitive to humidity, it can ensure that the products are always in a dry environment during storage and transportation.
In summary, packaging bags are going further and further on the road of moisture-proof with the dual guarantee of special materials and advanced technology. They play an irreplaceable role in protecting the quality of goods and extending the shelf life of goods. They meet the stringent requirements of many industries for moisture-proof packaging and promote the continuous development of the packaging industry.
