Canning and Fish Packaging Technology

Unit 9 - Plastics for Packaging

9.3.5.Expanded polystyrene (EPS)
Produced by mixing PS heads with 5 to 7% blowing agent such as pentene or chlorofluorocarbon and steam heating at 95oC. PS begins to soften and blowing agent is released from the solid solution causing rapid expansion of the beads giving a cellular structure.

EPS is an excellent heat insulator used for containers for hot take away foods or for boxes for transporting fresh (iced) fish. They are also used for packing where cushioning is required (Eg. egg trays or fruit or tomato) or as cushioning materials.