Material & Barrier Technical Overview
The material structure of a stand-up pouch directly determines its barrier performance, mechanical strength, sealing reliability, shelf life, and application range. A suitable material combination should be selected according to the packaged product, storage conditions, filling process, and required shelf life.
Film Structure
Stand-up pouches are commonly manufactured using multi-layer laminated films. Each layer performs a specific function. PET and BOPP are frequently used as outer layers because they provide good printability, stiffness, dimensional stability, and abrasion resistance.
PE and CPP are commonly used as heat-sealing layers. They provide reliable sealing performance and can be selected according to the required sealing temperature, seal strength, and product compatibility.
For demanding applications, aluminum foil or metallized films can be incorporated into the structure to improve protection against oxygen, moisture, light, and aroma migration.
Barrier Performance
Barrier requirements depend heavily on the characteristics of the packaged product. Oxygen barrier is important for products sensitive to oxidation, while moisture barrier helps prevent humidity from affecting dry foods, powders, and other moisture-sensitive products.
Light-sensitive products may require an aluminum foil or high-opacity structure to reduce UV and visible-light transmission. For coffee, tea, spices, and aromatic products, effective oxygen and aroma barriers can help preserve flavor and freshness.
Common Material Combinations
A PET/PE structure provides a practical combination of strength, printability, and heat sealing and is suitable for many general food and consumer products.
PET/AL/PE provides enhanced protection against light, oxygen, moisture, and aroma, making it suitable for products requiring a high barrier.
PET/MPET/PE offers improved barrier performance while generally providing a lower material cost than full aluminum foil structures.
For applications requiring improved sustainability, mono-material PE or PP structures may be considered when the required mechanical and barrier properties can be achieved.
Material Selection Considerations
Material selection should consider product sensitivity, shelf-life requirements, filling temperature, sealing conditions, storage environment, transportation requirements, and regulatory compliance.
The final structure should be validated through appropriate testing, including seal strength, leak resistance, oxygen transmission rate (OTR), water vapor transmission rate (WVTR), and overall package integrity. Correct material selection helps balance product protection, manufacturing performance, appearance, and cost.
References
ISO 15106 – Plastics — Film and sheeting — Determination of water vapour transmission rate
ASTM D3985 – Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting
ASTM F88 – Standard Test Method for Seal Strength of Flexible Barrier Materials
ASTM F2096 – Standard Test Method for Detecting Gross Leaks in Packaging by Internal Pressurization
ISO 11607 – Packaging for Terminally Sterilized Medical Devices
