The gas barrier properties of ethylene vinyl alcohol copolymer (EVOH) against oxygen, carbon dioxide and water vapor have been widely investigated in relation to different material characteristics, environmental conditions and new processing technologies. Recently, EVOH is gaining more attention as a barrier material against other gases and organic substances such as aromas, flavors, fuels, chemicals (e.g., BTEX), and as a functional barrier, e.g., to avoid mineral oil migration. This review contains an update on permeability data of EVOH emphasizing its potential as a barrier material for new and versatile applications in food and pharmaceutical packaging, agriculture, construction, automotive, etc.

Ethylene vinyl alcohol copolymer (EVOH) is a key material of interest as a functional barrier against substances migrating from recycled paperboard, due to its outstanding barrier properties. Three multilayer films containing two different grades of EVOH, L171B (3 µm) and F171B (3 and 5 µm), were benchmarked against a multilayer film containing polyamide 6/6.6 copolymer (PA 6/6.6, 3 µm) and monolayer polyethylene terephthalate (PET, 12 µm). The 5 films were evaluated as barrier materials against 5 surrogate substances simulating different migrants potentially present in recycled paperboard: n-heptadecane (C17) as a mineral oil-saturated hydrocarbon (MOSH), 4-methylbenzophenone (MBP) as a photoinitiator, di-n-propyl phthalate (DPP) as a plasticiser, and anthracene (ANT) and perylene (PER) as mineral oil aromatic hydrocarbons (MOAHs). The test was accelerated at 60°C for 25 days, which is equivalent to a shelf life of 2 years at 25°C. All films containing 3 or 5 µm EVOH were found to be good barriers, showing no breakthrough values over 1% of the initial concentration found in the paperboard, and they could easily compete with 12 µm PET. The multilayer with 3 µm PA 6/6.6 showed higher breakthrough values for both MBP and DPP than the other materials although still below the 1% threshold value. However, ANT showed substantial breakthrough values of nearly 2%, indicating that PA 6/6.6 might not offer enough protection against low-weight MOAH components.

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