Blown film extrusion is a technology that is the most common method to make plastic films,
especially for the packaging industry. Typically, blown film extrusion is carried out vertically upwards, however horizontal and downward extrusion processes are now becoming more common. The process involves extruding a tube of molten polymer through a die and inflating to several times its initial diameter to form a thin film bubble. This bubble is then collapsed and used as a lay-flat film or can be made into bags.
EPS is an Expandable Polystyrene containing pentane as a blowing agent, produced from solid beads of Polystyrene. Expansion is achieved by small amounts of pentane gas as a blowing agent dissolved into the Polystyrene base material during production. The gas expands under the action of heat, applied as steam, to form perfectly closed cells of EPS. These cells occupy up to 30-50 times the volume of the original polystyrene bead. The EPS beads are then moulded into appropriate forms suited to their application.
Extrusion coating is a process of coating thermoplastic material onto a substrate such as woven fabric, paper, paperboard aluminum foil, PET, BOPP film, etc. The resins most commonly used are polyolefins such as polyethylene and polypropylene.