Canning and Fish Packaging Technology

Unit 10 - Manufacture of plastic packages

10.1.2.7.Extrusion coating
A large proportion of flexible packaging materials are extrusion coated using polyethylene with 10-50 micron thickness as the inner heat seal layer. Other ethylene polymers such as EVA, ionomer and various polymers such as PP, PET are also coated, e.g. PET is coated on paper board for making ovenable trays.
Extrusion coating process somewhat similar to co-extrusion process using a flat slit die, but the main difference is that the web is being coated.
Extrusion coating can be applied to paper, paper board, foil laminate, metalized plastic sheets provided they have sufficient heat stability.