Foam-beads
Raw material under pressure
Expanded EPP is already pre-foamed to foam-beads at the resource manufacturer.
There are two types of raw material, autoclave-foamed EPP and foam-extruded EPP. The most frequently used substance is the autoclave-foamed one. Thereby, polypropylene-pellets are loaded up with an easily evaporating hydrocarbon (mostly butane) in an autoclave under pressure and elevated temperature. When draining the autoclave, the pellets froth up to EPP foam-beads.
The extruded EPP can easier be produced in different colors and is more temperature-resistant. However, at the fabrication of shaped parts higher steam pressure is necessary. The autoclave-foamed EPP mostly has better energy-absorption-values, but is offered only in grey and white standard.
