What is unique about PP barrier sheet?

Common PP barrier sheet materials

Common materials for PP barrier sheet include the following. These materials are added on the basis of PP (polypropylene) sheet through multi-layer co-extrusion technology or functional coating, and have the ability to block gas and moisture:

PP/EVOH/PP structure
This is the most common PP barrier sheet structure. The EVOH (ethylene vinyl alcohol copolymer) layer has extremely strong oxygen and moisture barrier properties and is the core of barrier performance. The PP layers on both sides provide mechanical strength and heat resistance.

PP/PA/PP structure
The PA (polyamide) layer has good gas barrier and oil resistance, and is often used in packaging that requires high strength and chemical resistance.

PP/metal foil/PP structure
The metal foil layer (such as aluminum foil) has extremely strong barrier properties and is often used in packaging that needs to be completely isolated from oxygen, water vapor and light.

PP/PE/EVOH/PE/PP
This is a multi-layer composite sheet consisting of PP, PE (polyethylene) and EVOH layers. The EVOH layer provides gas barrier and the PE layer provides flexibility and sealing performance. It is often used in food packaging that requires high barrier and sealing.

PP/SiOx coating
This sheet improves the gas and water vapor barrier performance by adding a layer of SiOx (silicon oxide) coating on the surface of the PP sheet. The silicon oxide coating can effectively reduce the permeability of oxygen and water vapor and enhance the barrier performance of the sheet.

The uniqueness of PP barrier sheet compared to ordinary PP sheet

Gas barrier property
Ordinary PP sheet has weak gas barrier performance, and gases such as oxygen and carbon dioxide can easily penetrate through the material. The barrier PP sheet significantly improves the gas barrier performance of the material by adding barrier layers such as EVOH, PA or special coatings, which is especially suitable for food packaging that needs to extend the shelf life.

Moisture barrier property
The barrier sheet has stronger barrier properties to water vapor and moisture than ordinary PP sheet. Barrier materials such as EVOH and PA can not only effectively block gases, but also reduce the penetration of moisture, thereby keeping the contents of the package dry and fresh.

Extending the shelf life of food
Due to its improved barrier properties, PP barrier sheets are widely used in food packaging, especially foods that need to be stored for a long time, such as frozen foods, cooked foods, dairy products, etc. This type of sheet can effectively reduce the impact of oxygen and moisture on food, thereby extending the shelf life, while ordinary PP sheets cannot achieve the same effect.

Multi-layer structure design
PP barrier sheets usually use multi-layer co-extrusion technology to improve comprehensive performance by compounding materials with different functions. Ordinary PP sheets are mostly single materials and cannot meet multiple needs at the same time. The multi-layer structure of barrier sheets enables it to maintain mechanical strength and provide barrier functions.

Specific application scenarios
Barrier PP sheets are widely used in food, medicine, cosmetics and medical devices that have high freshness requirements for packaging, while ordinary PP sheets are more used in scenarios that do not require high barrier properties, such as ordinary industrial product packaging, non-food packaging, etc.

Conclusion

By adding functional materials or coatings, PP barrier sheets have stronger gas and moisture barrier properties than ordinary PP sheets, and are widely used in food preservation, medicine and cosmetic packaging. The multi-layer structure design gives it better comprehensive performance, enabling it to perform well under stringent packaging requirements.