Polystyrene foam is a type of plastic produced from styrene. It is a lightweight, moisture-resistant material with exceptional insulation properties. Since it is composed of more than 90 percent air, this foam is also remarkably buoyant.
There are two kinds of Polystyrene Foams:
1. Expandable Polystyrene / EPS
Expandable Polystyrene / EPS usually use as packaging for many kind of products such as television, electrical appliances, helmet, ice box, sheet foam and block foam for road construction. EPS foam bead contains 98% air per volume, only 2% is plastic. This make EPS foam very light weight, has low thermal conductivity because air is the best insulation, high compressive strength and excellent shock absorption. These properties make EPS to be ideal material for packaging and construction.
2. Extruded Polystyrene / XPS
Polystyrene Paper / PSP, so called Extruded Polystyrene / XPS, is used to produce food tray and food box. It is a PS Foam which produced by extruding process as another plastic. Production process start when put polystyrene resin pellets into the extruder that heated by electric. Foaming process occur at the end of extruder where the blowing agent, butane (C4H10) gas react with the melt plastic then become foam. The melted polystyrene foam then extended as sheet then roll as paper roll, that is why commonly known as “Polystyrene Paper”. The polystyrene foam sheet or polystyrene paper can be produced as many shape according to the mold by thermal forming process such as food tray, cups, bow, and food box.