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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
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 be
blends require to be
compatibilized
compatibilized
PA/EVOH/PE
PA6 provides mechanical strength and
abrasion resistance,
EVOH provides oxygen barrier,
PE provides sealability and protects EVOH
against moisture.