Film Blowing
Also called: Blown film extrusion, blown film
Film blowing makes plastic film by extruding a tube of molten polyethylene and inflating it into a thin bubble that is cooled and flattened.
Film blowing, or blown film extrusion, is the main process for making polyethylene film. Molten plastic is extruded through a circular die to form a tube, which is inflated with air into a large bubble, cooled, pulled upward and flattened into a double layer of film. The film is then wound, slit, printed or converted into bags and liners.
Why it matters when buying recycled plastic
- Film is thin, so gels, unmelted particles and small contaminants cause holes and breaks. Material needs good melt filtration.
- LDPE, LLDPE and HDPE film grades are usually low MFI; bubble stability depends on melt strength.
- Moisture in washed film recyclate causes bubbles and lacing in the film.
- Recycled share is often limited for thin, clear film and higher for thicker, coloured or black film such as garbage bags.
Common products
Carry bags, liners, garbage bags, shrink film, agricultural film, lamination film and industrial packaging. Film plants generate trims and rejects that are recycled as agglomerate.