When we design a packaging solution, we can’t get away without two key indicators: OTR and WVTR.

so what is OTR, what is WVTR, and what do these two indicators refer to? What is the significance of paying attention to them?

Actually, all polymers have varying degrees of permeability to gases and vapours. Therefore the permeability to gases and vapours is tested to determine the barrier properties of the material in order to select the right material for the packaging.

For gas permeability, we correspond to the oxygen transmission rate (OTR) and for vapour permeability, we correspond to the water vapour transmission rate (WVTR), so we also say that OTR and WVTR are the two key material specification properties that determine the shelf-life of packaging (especially food packaging).

So how do we understand the barrier properties of packaging through these two key indicators?

Barrier Grade	OTR & WVTR Data	Material Structure Example
High barrier	≤1.0	Tradition: PA/AL/PA/PE Recyclable: BOPP/MBOPP/CPP
Medium barrier	1.0-10	Tradition: PET/AL2O3-PET/PE Recyclable: MDOPE/EVOH-LLDPE Compostable: Cellulose/PBS (PLA)
No barrier	>10	Tradition: PET/PE Recyclable: MDOPE/LLDPE, BOPP/CPP Compostable: Paper/PBS (PLA)

Which products need barrier material packaging?

Products such as coffee, snack foods, protein powders, tablets, select dry ingredient foods can be severely affected by any air or moisture that enters the bag. With barrier packaging film, you can optimize the shelf life of your products and provide your customers with the highest quality products.