Polystyrene granules compose about 90-95% of a XPS board.
Blowing agents (up to 8%) are the main compound needed for
extrusion and foam forming. Other additives, such as colorants,
flame retardants and nucleants make about 2% to contribution.
Electricity is the main power source of the extrusion process.
Extrusion process uses some water in the enclosed system, which is
needed for cooling processes.