Comparison of Packaging Films Based on Oxygen (OTR) and Water Vapor (WVTR) Transmission Rates
🔹 Introduction
In the packaging industry—particularly for food, pharmaceuticals, and moisture- or oxygen-sensitive products—two key parameters play a critical role in selecting the appropriate film:
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OTR (Oxygen Transmission Rate): The amount of oxygen that passes through a film over a given area and time.
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WVTR (Water Vapor Transmission Rate): The amount of water vapor that passes through a film over a given area and time.
These two values are crucial in maintaining product quality, preventing spoilage, and extending shelf life. This article compares commonly used packaging films based on their OTR and WVTR values.
🔹 Definition of OTR and WVTR
| Parameter |
Definition |
Unit |
Importance |
| OTR |
Amount of oxygen passing through a film surface |
cc/m²/day |
Critical for oxidation-sensitive products |
| WVTR |
Amount of water vapor passing through a film |
g/m²/day |
Important for moisture-sensitive products |
🔹 Comparison Table of Common Films by OTR and WVTR
| Film Type |
OTR (cc/m²/day) ↓ Better |
WVTR (g/m²/day) ↓ Better |
Notes |
| PET |
45–65 |
3–5 |
Transparent, strong, needs sealant layer |
| BOPP |
1500–2000 |
2–4 |
Lightweight, sealable with EVA or PE layer |
| LDPE |
2000–8000 |
10–30 |
Economical but permeable |
| PVC |
500–600 |
5–10 |
Transparent, less common due to sustainability |
| PA (Nylon) |
10–20 |
30–100 |
Mechanically strong, poor water vapor barrier |
| EVOH |
0.1–1 |
0.5–5 |
Excellent oxygen barrier |
| Aluminum Foil |
~0 |
~0 |
Complete barrier, used in laminates |
| Multilayer (PET/Al/PE) |
~0–5 |
~0–2 |
Ideal for vacuum packaging and extended shelf life |
🔹 Film Selection by Product Type
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Oxidation-sensitive products (e.g., chips, coffee, oil):
Use films with low OTR, such as EVOH or Al-laminates.
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Moisture-sensitive products (e.g., biscuits, powder, salt):
Use films with low WVTR, like PET or PET/PE laminates.
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Frozen or fresh products:
Combine mechanical strength and sealability, such as BOPP/EVA or PA/PE.
🔹 Key Considerations in Film Selection
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Multilayer films outperform monolayers
Laminated films (2–3 layers) combine barrier, seal, and mechanical strength.
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Film thickness affects OTR and WVTR
Thicker films generally provide better barrier properties.
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Coatings (e.g., PVDC, SiOx)
Can be applied to enhance barrier performance without using foil.
🔹 Conclusion
Choosing the right film for packaging goes beyond cost and appearance. For high-quality, long-shelf-life packaging, understanding OTR and WVTR values is essential. Laminated films using materials like EVOH or aluminum foil provide superior performance and are leading the way in modern sustainable packaging solutions.