Vacuum packaging is suitable for various plastic composite films and plastic-aluminum foil composite films. Common material combinations include PET/PE, PET/PP, NY/PE, NY/PP, PP/PE, PET/AL/PE, BOPP/AL/PE, and PP/NY/PE. These films need adequate gas barrier properties, pressure resistance, and mechanical adaptability.
Common Composite Packaging Materials: Properties and Applications
The table below summarizes the required properties and recommended composite film combinations for different food product categories:
| Product Category | Required Properties | Composite Film Examples |
|---|---|---|
| Rice-based snacks | Moisture resistance, oil resistance, cold resistance, tear resistance | KPT/PE, OPP/CPP, OPP/PE |
| Instant noodles | Moisture resistance, oxidation resistance, machinability, insect resistance, aroma retention | PT/PE |
| Snack foods | Gas barrier properties, anti-corrosion | KPT/OPP, PVDC/OPP, KPT/PE/BOPP |
| Juice powder | Moisture resistance, oxidation resistance | PRT/PE, KPT/PE, PET/AL/PE, PET/PVDC/PE |
| Soybean paste | Anti-mold, gas barrier, hot water sterilization resistance | ON/PVDC/PE, ONY/EVAL/PE |
| Pickled vegetables | Vacuum degassing, pinhole resistance, anti-static | OPP/PE, PET/PE |
| Milk powder | Moisture resistance, oxygen barrier | PVDC-coated cellophane/AL/PE |
| Ham, sausage | Gas barrier, moisture resistance, vacuum gas filling compatibility | PVDC-coated cellophane/PE, PET/PE, PVDC/PET/PE, PVDC/PP/PE |
| Tea | Moisture resistance, light barrier, gas barrier, aroma retention, pinhole resistance | OPP/AL/PE, PET/PE/paper/AL/PE |
| Seasonings | Gas barrier, aroma retention, oil resistance | NY/PE, PVDC/PET/PE |
| Frozen foods | Low-temperature sealability, oil resistance | PA/PE, PET/PE, NY/PE |
| Retort sterilized foods | Long-term preservation, heat resistance to 125°C | High-barrier retort-grade composites |
Key Material Abbreviations
Here are the common material abbreviations used in the industry:
- KPT — PVDC-coated polypropylene film (high-barrier)
- OPP — Oriented polypropylene
- BOPP — Biaxially oriented polypropylene
- CPP — Cast polypropylene
- PE — Polyethylene (sealant layer)
- PET — Polyester (polyethylene terephthalate)
- NY (PA) — Nylon (polyamide)
- PVDC — Polyvinylidene chloride (oxygen and moisture barrier)
- AL — Aluminum foil (complete light and gas barrier)
- EVAL (EVOH) — Ethylene vinyl alcohol copolymer
- ON/ONY — Oriented nylon
Property Requirements by Food Type
Each food product category asks for something different from its vacuum packaging:
Moisture-sensitive products (rice snacks, juice powder, milk powder, tea) require films with strong moisture barrier properties. These typically incorporate aluminum foil (AL) or PVDC as the barrier layer, laminated with PE for sealability. For example, PET/AL/PE is commonly used for juice powder — the PET provides printability and structural strength, AL provides the moisture and oxygen barrier, and PE provides the heat-seal layer.
Oil-containing products (rice snacks, seasonings, frozen foods) need oil-resistant films. Nylon (NY) and PET-based composites excel here, as these polymers resist oil penetration that would otherwise delaminate standard PE films.
Aroma-sensitive products (tea, seasonings, instant noodles) demand high aroma barrier properties. Aluminum foil-based composites provide the best aroma retention, which is why tea packaging commonly uses OPP/AL/PE or PET/PE/paper/AL/PE structures.
Gas-sensitive products (snack foods, ham, soybean paste) require oxygen barrier properties to prevent oxidation and spoilage. PVDC-coated films (KPT, KOP) or EVOH-based composites are standard choices. For ham and sausage packaging, PVDC/PET/PE and PVDC/PP/PE provide the necessary gas barrier while maintaining good vacuum forming characteristics.
Frozen foods require low-temperature sealability and resistance to brittle fracture at freezer temperatures. PA/PE and NY/PE combinations provide the necessary cold-temperature toughness with reliable PE seal layers.
Retort-sterilized products have the most demanding requirements — the package must withstand 125°C sterilization temperatures while maintaining seal integrity and barrier properties throughout extended shelf life.
Selecting the Right Composite Structure
When selecting vacuum packaging materials, consider these factors:
- Product requirements — Identify which barrier properties (moisture, oxygen, light, aroma) and mechanical properties (puncture resistance, tear strength, seal integrity) the product needs.
- Processing conditions — Consider the processing temperature (ambient, refrigerated, frozen, or retort), vacuum level, and filling speed.
- Shelf life targets — Higher barrier structures (AL foil, PVDC, EVOH) extend shelf life but add cost. Match the barrier level to the required shelf life.
- Packaging machine compatibility — The composite structure must be compatible with the specific vacuum packaging machine’s forming, filling, and sealing parameters.
- Cost optimization — Balance performance with cost. KPT/PE costs less than PET/AL/PE but provides sufficient barrier for many snack applications.
References
- Wikipedia: Vacuum Packing: Overview of vacuum packaging technology and applications
- Wikipedia: Plastic Film: Comprehensive reference on plastic film types and manufacturing
- ASTM D3985 — Oxygen Gas Transmission Rate of Plastic Film: Standard test method for measuring oxygen transmission through plastic films
- FDA: Food Ingredients and Packaging: U.S. FDA regulations for food contact packaging materials
- ISO 15105 — Plastics Film — Gas Transmission Rate: International standard for gas transmission rate determination