| The use of physical blowing agents, carbon dioxide or nitrogen, in extrusion foaming processes gives lighter parts and lower consumption of raw material.
The physical blowing agent is first injected with great accuracy into the polymer melt by means of a metering unit and then dissolved in the polymer. The pressure is maintained throughout the extruder. A rapid pressure drop rate creates a homogenous cell structure of foamed polymer resulting in a light, strong product that can be used in a wide range of applications by the packaging, automotive, electric and manufacturing industries.
Typical products foamed with carbon dioxide are extruded polystyrene (XPS) insulation boards or extruded polystyrene foam sheets for food packaging.
Nitrogen is mainly used in production of polyethylene cable insulation. |
