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It is well known that traditional polymers are permeable to gazes
such as oxygen, CO
2
, vapor This property can become critical for
food conservation or storage of gaseous beverages. This is the
reason why, in most of the cases, multilayers structures are used.
They are composed of a core barrier material and inert outerlayers
like polyolefin. Typical Barrier materials are highly crystalline like
EVOH, Polyamide, polyester. Aluminium foil or Carton can also be
used (example Tetrapak).
BARRIERS TO GASES
MULTILAYER MATERIALS
MATERIALS
Applications
Comments
Recyclability
PA/PE
Applications: ham, meat cheese,
pasta...
PA provides oxygen barrier and
outer abrasion resistance whereas
PE provides sealability and
flexibility.
blends require to
blends require to
be compatibilized
be compatibilized
PA/EVOH/PE
PA6 provides mechanical strength
and abrasion resistance,
EVOH provides oxygen barrier,
PE provides sealability and protects
EVOH against moisture.