Oxygen Transmission Rate (OTR) Calculator
Calculate the permeation rate of oxygen through polymer films and barrier materials.
Unit: cc·µm / (m² · day · atm)
Unit: micrometers (µm)
Atmospheres (atm) – Air is 0.21
Estimated Oxygen Transmission Rate:
0.00
cc / (m² · day)
Understanding Oxygen Transmission Rate (OTR)
Oxygen Transmission Rate (OTR) is a measurement of the amount of oxygen gas that passes through a substance over a specific period. In the packaging industry, particularly for food and pharmaceuticals, OTR is a critical metric used to determine the shelf life of products sensitive to oxidation.
The Mathematical Formula
OTR = (P × Δp) / L
- P: Permeability coefficient of the polymer material.
- Δp: The partial pressure difference of oxygen across the film.
- L: The thickness of the film (usually in microns or mils).
Key Factors Influencing OTR
- Temperature: Permeability increases exponentially as temperature rises. Most OTR tests are conducted at 23°C or 37°C.
- Relative Humidity (RH): For certain materials like EVOH or Nylon, moisture significantly increases the OTR as the polymer matrix swells.
- Thickness: Generally, doubling the thickness of a homogenous material will halve the OTR.
Typical OTR Values (cc/m²/day at 23°C, 0% RH)
| Material (25µm) | Typical OTR Range |
|---|---|
| EVOH (High Barrier) | 0.1 – 2.0 |
| PET (Polyester) | 30 – 50 |
| PP (Polypropylene) | 1,500 – 2,500 |
| LDPE (Polyethylene) | 6,000 – 8,000 |