Oxygen Transmission Rate (OTR) Testing for Breathable Packaging

When packaging oxygen-sensitive food products, such as produce or meats, maintaining freshness and shelf-life is of high concern. The atmospheric conditions inside of a package contribute directly to the success or failure of preserving perishable goods. Modifying the internal environment of the package (moisture, oxygen, and carbon dioxide in particular) will slow down the naturally occurring deterioration process, preserving the product’s fresh state for a longer period of time. While there are several different methods for controlling this exchange of gases, using laser microperforating as a breathable packaging production solution will deliver the precise oxygen transmission rate required for each individual product.

Measuring OTR

The Oxygen Transmission Rate (OTR) is a calculated measurement of the amount of oxygen gas that over a given period of time at a steady rate passes through a substrate. The goal of perforated breathable packaging is to achieve a balance between declining oxygen levels and increasing carbon dioxide levels. Oxygen transmission rates are expressed in cc/m²/24 hours (cc/100in²/24 hours), and are used to give value to the oxygen barrier capabilities of a flexible packaging film. A film that is considered to have a “high barrier” has an oxygen transmission rate range of approximately 1-10 cc/m²/24 hours, a “moderate transmitter” film will have a rate of approximately 1,000 cc/m²/24 hours, and a “high transmitter” film will have an oxygen transmission rate of approximately 10,000 cc/m²/24 hours.

While flexible packaging films each have an approximate “base” OTR, that rate can increase with the introduction of perforations to allow for amplified oxygen flow. The level of oxygen and carbon dioxide that results from produce respirations within each package will depend on the interaction between the respiration rates of each product and the perforated pattern. The size, number, and type of perforations all contribute to the oxygen transmission rate of a breathable package and will differ depending on the type of film used. Other factors to consider are the polymerization process as well as the thickness of the barrier film, product type, package volume, head space, and product weight. Each variable results in a unique oxygen transmission rate, as the number/size/pattern of perforations will never be exactly the same from one film to another.

OTR Testing Process

The OTR testing process at LaserSharp FlexPak Services is based on ASTM D3985: Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor. Using an OxySense 5000 Oxygen Analyzer System, a non-invasive oxygen measurement system, nitrogen is flushed through a chamber in which the film sample has been placed. The film in the chamber separates the nitrogen on one side, from the oxygen on the other. Oxygen molecules move through the film to the low-pressure side, with the film barrier determining the rate of the oxygen transmission. A coulometric sensor placed on the outgoing nitrogen side measures this rate of oxygen transmission. The test is deemed complete when a state of equilibrium is reached and the amount of oxygen flowing through the outgoing nitrogen side is equivalent to the oxygen on the incoming side.

Offering in-house oxygen transmission rate testing, in addition to a range of laser converting services, allows LaserSharp FlexPak Services to guide you through every step of the breathable packaging process. From developing the exact perforation sizes and patterns based on your specific product’s required OTR, to producing test samples and full-scale commercial production runs of your perforated breathable packaging, FlexPak is your one-stop service solution. 
LaserSharp FlexPak Services has experience in the development, testing, and laser converting of breathable packaging for a wide variety of products. From achieving extremely high oxygen transmission rates of 10,000 for the fish industry, to very low rates for apples, FlexPak is prepared to help find just the right pattern and size combination to achieve the exact rate for your product. Whether you have a question regarding the OTR testing process, or if you’ve already identified an OTR that you wish to achieve, contact LaserSharp FlexPak Services to find out how our OTR testing and laser microperforating services will benefit you, your product, and your customer.