Material

Expanded Polystyrene (EPS) is a closed cell, thermoplastic, lightweight, rigid cellular plastic material with a wide range of useful properties. It is transformed into finished products in automated processing machinery.

Processing
EPS raw material is delivered as small beads, typically 0.5mm diameter. The beads are impregnated with a small amount of pentane gas to aid expansion. The beads are then heated using steam in a machine called a pre-expander. The action of the steam heating causes the beads to expand to about 40 times their original size. The expanded beads are similar to those found in a ‘bean bag’ and contain approximately 98% air. After expansion, the beads are aged for typically 24 hours, allowing the beads to stabilise. Once stabilised, the EPS beads are transferred to a moulding machine and injected into a mould. The moulding machine applies steam and pressure, which fuses the beads together into the required shape. Following a cooling cycle, the finished part or product is ejected from the machine. See also www.plastics.org.nz

Properties
Amongst it’s useful properties, EPS has low thermal conductivity, and therefore is extensively used as an insulating material. It is widely used for building insulation and to package fresh fish, produce and many other food products. It is able to help keep food fresh throughout it’s often long journey to the end user. See www.plastics.org.nz

With its strong cushioning ability, it has excellent shock absorbing properties, and therefore very useful for protecting delicate items. Home appliances, electrical and electronic goods, medical products and many other fragile items are packaged in EPS and benefit from the excellent cushioning properties. See www.plastics.org.nz

EPS is odourless and non-toxic. It does not emit chlorofluorocarbons (CFCs), and is recyclable. It provides outstanding value and performance as a material in a wide range of applications.