There is still today no single polymer available which offers all these properties by itself. Coextrusion technology grew out of these market requirements. Coextrusion is a technology which incorporates various layers of distinct polymers in a single structure, either in flexible or rigid form, and this final structure allows the necessary properties to be achieved to satisfy the barrier requirements of many food products.

Polypropylene (PP) provides an excellent water vapor barrier; good stiffness at low density for high yields; and excellent chemical, stress crack and high temperature resistance. EVOH (ethylene-vinyl alcohol copolymer) material provides outstanding gas barrier properties while retaining good process ability. The excellent gas properties of EVOH keep oxygen out and retain nitrogen and carbon dioxide used in Modified Atmosphere Packaging (MAP) and Equilibrium Modified Atmosphere Packaging Technology.