Blown film is plastic film produced by extruding molten polymer through a ring-shaped die and inflating it with air into a tall, thin bubble. The bubble is cooled, collapsed flat and wound into rolls, which are later converted into bags, liners, pouches and wraps.
Most polyethylene packaging film is made this way, from LDPE, LLDPE and HDPE. Blown film is also the main use for rLDPE granules, on their own or blended with virgin polymer. Because the film is very thin, recycled grades for it must be well filtered and free of gels and moisture, otherwise the bubble breaks. Products such as shrink wraps, stretch wraps and poly bags all start as blown film.
