Expanded Polystyren, EPS

EPS is made up of 98% air. Due to its extremely low weight, its use as a packaging material minimizes the total product weight. This reduces transportation costs compared with other packaging materials. In turn this means that transport fuel consumption is improved and vehicle emissions are minimized. All contributing to lower global warming.

The thermal insulation properties help keep food fresh through the distribution chain. It is widely used to package fish and for seed trays where low heat loss assists in the growth of the plants.


The exceptional durability means that it can effectively protect a wide range of goods. There is no loss of strength in damp conditions, making EPS ideal for cool-chain food products. The fact that the material is moisture resistant also means that the highest hygiene requirements are met.

Expanded polystyrene (EPS) is used for the production of a number of applications. However its major application is as a protective packaging for consumer electronic products and white goods. Its excellent thermal insulation and mechanical protection properties make it ideal to package fish and other foodstuffs. EPS also has applications in horticulture as seed trays.

The outstanding shock absorbency of expanded polystyrene packaging ensures the protection of a broad range of products. Moreover, its compression resistance means that EPS is ideal for stackable packaging goods. When safety is paramount, EPS comes into its own. It is used in the manufacture of children's car seats and cycling helmets, where its protective qualities, strength and shock-absorbency are vital.

The Production and Moulding Process

Unlike other thermoplastic processes, the production of EPS products requires that the raw materials be pre-conditioned prior to their final "tooled" moulding process.
The raw material (also known as "expandable polystyrene" or "bead") has a sperical shape and is similar to sugar in appearance

The conversion process is carried out in three stages:

Pre-expansion

The tiny spherical polystyrene beads are expanded to about 40 times their original size using a small quantity of pentane (typically 5% by weight) as a blowing agent. This process involves the heating of beads, using a flow of steam, which causes the blowing agent to boil and thus a honeycomb of closed cells is formed.

Maturing

As the material cools the pentane liquefies and a partial vacuum is formed inside the bead. The beads are returned to a holding tank for approximately twelve hours to allow the pressure differential to equalize, giving a stabilised granule.

Final Forming

In this final stage the pre-expanded stabilized beads are reheated with steam in a mould. The final expansion takes place and the beads coalesce to give a shaped moulding. This can also be used to form large blocks which can be sectioned to the required shape as panels, boards, cylinders etc. In this final form the EPS is made up of 98% air.