9. The layflat film travels over a series of rollers. For simple bags, such
as trash bags or industrial bags, the film is contained to a single,
in-line process. In this case, the polyethylene film:
− Travels through a bag machine that seals the bottom of the plastic
bag and perforates it at the same time. The perforation allows the
bags to be easily torn from the roll.
− May also travel through a separator that breaks the perforations
and stacks the poly bags on top of each other for bulk packaging in
a box.
10. For poly bags with complex features (for example, multi-colored
printing, Zip-Loc® closure, or door knob hang holes) the film is
wound on a roll and then taken out of line for further processing at a
converting facility. A converting facility has a variety of specialized
equipment to create the diverse features found in plastic bags today.
The blown film extrusion process for creating poly bags hasn’t changed
much over the years. But what has changed is how we use plastic bags
in our daily lives – whether we carry home groceries in “T-shirt” plastic
bags or seal an expensive cut of meat into an air-tight freezer bag. What
was once a novelty is now an everyday convenience that makes our lives
easier.