Despite the jargon, Moisture Vapour Transmission Rate (MVTR) is actually a useful metric. It’s a measure of the amount of water vapour that can pass through a material, during a given period of time. The better the MVTR of a barrier material, the better it is in preventing moisture ingress. Attention to this issue can help you avoid expensive recalls and damage to your reputation. In 2012, it was found that 67% of pharmaceutical shortages in the US were due to quality issues,1 underscoring the importance of MVTR considerations.
MVTR is a critical concept when it comes to packaging materials in the Pharmaceutical Industry, where products can be sensitive to moisture. Expose these formulations to even a few grams of water, and you could end-up with a highly compromised product!
When selecting packaging materials for moisture-sensitive products, it’s essential to get materials with a low MVTR, as they enhance both the stability and shelf-life of your products.
What Level of MVTR is Best for Your Packaging’s Barrier Materials?
Whether or not your product’s packaging requires a low or high MVTR material will depend on:
1. The susceptibility of your product to moisture damage
2. The length of shelf-life period that is required
3. The humidity of the environment where packaging is going to be used or stored
4. The budget that you have available to spend on the packaging as a percentage of your total cost of goods
5. Whether or not you are adding a desiccant into the pack
6. The size of the pack and interior head-space
“It’s essential to get materials with a low MVTR, when selecting packaging materials for moisture-sensitive products”
What are ‘Typical’ MVTR Values?
MVTR is measured in grams of moisture, per square meter, per day (g/m²/day). These values can vary greatly depending on the type of material used. They can range from less than 0.1g/m²/day for barrier foils to more than 20 g/m²/day for non-barrier materials. For instance, non-plastic wood-pulp packaging (such as paper and cardboard) will have MVTR ranges from 10-50 g/m²/day.
How is MVTR Measured?
MVTR is measured using specialized equipment, such as a Permeation Test Chamber. These machines measure the amount of moisture vapor that passes through a known area of the material, during a specified period of time. The sample is usually placed between two chambers, one of which is kept at a high Relative Humidity (RH), while the other is kept at a low relative humidity. The change in humidity between the two chambers, over time, is used to calculate the MVTR.
Another (less common) technique is the Gravimetric Method. Here, the test material is sealed onto a metal dish, with a desiccant underneath, and placed in a climate chamber. The weight gain of the desiccant over time can then be accurately measured, and used to determine the permeability of the barrier material.
Typical Packaging Materials and MVTR Values
Examples of High Moisture-Barrier Materials (i.e. with low MVTR values)
o 12um PET/12um Aluminium Foil/75um LDPE.
o 12um PET/9um Aluminium Foil/50um LDPE.
§ When measured to DIN 53122 test standard they will typically have a performance <0.05g/m2/day.
§ These are used in instances where high barrier is essential for long shelf life/high product stability (e.g. medical devices or diagnostic products)
Examples of Medium Moisture-Barrier Materials (i.e. with intermediate MVTR values)
o 12um Metallised 25um OPP/25um OPP
o 12um Metallised PET/50um LDPE
§ When measured to DIN 53122 test standard they will typically have a performance <0.5-1.0g/m2/day.
§ These could be used for packaging requirements where some, but shorter shelf life/less stability is required (e.g. dry foodstuffs or nutraceutical powders)
Examples of Low Moisture-Barrier Materials (i.e. with High MVTR values)
o 12um PET/50um LDPE
o 18um OPP/25um OPP
§ When measured to DIN 53122 test standard they will typically have a performance <5.0-10g/m2/day
§ These could be used for more general packaging requirements with little or no barrier to moisture vapour is required, such as playing cards
Overall, Barrier Foil is one of the best packaging materials when it comes to moisture-proofing your product. The thin layer of aluminium foil, laminated onto a variety of other materials (such as paper or a thin plastic film like polyethylene), provides a near impenetrable barrier to moisture, whilst the other materials within the laminate provide additional strength and support. There are two main formats of our barrier foil: B-SURE™ Rolls, and B-SURE™ Pre-Made Pouches.
B-SURE™ Barrier Foil Rolls
B-SURE™ Foil Rolls provide a practical solution if your packaging line demands significant quantities of barrier foil lids, and is producing hundreds of thousands of blister packs per year. These foils can be customised to your requirements, including slit width, core size, external diameter, and wind direction. They are perfect for high-speed production lines, like form-fill-and-seal machines and flow-wrappers.
B-SURE™ Pre-Made Foil Pouches
If you’re a small or medium-sized business, and high-speed production equipment is not yet feasible, B-SURE™ Pre-Made Foil Pouches can save you time and money. They’re designed to make your packaging hassle-free, as we make the pouches to your specification, and deliver them to your door.
Let us Help You…
At Baltimore Innovations, we offer premium products and service, at an affordable price. We have over 60 years’ experience in dealing with foil laminates, so give us a call today on +44 (0) 1628 531 900, and let us help you…
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What to Read Next…
1: S. Shukar, F. Zahoor, K. Hayat, A. Saeed, A. H. Gillani, S. Omer, S. Hu, Z.-U.-D. Babar, Y. Fang, and C. Yang, “Drug shortage: Causes, impact, and Mitigation Strategies,” Frontiers in pharmacology, 09-Jul-2021. [Online]. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8299364. [Accessed: 31-Mar-2023]
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