17 Jun Virgin vs Regrind in Poly
in Product in Action
What is Poly?
Polyethylene sheeting is made from poly pellets that are melted and then extruded or blown through a machine to make the desired thickness of the sheeting. While the pellets are being melted, any additives such as fire retardant, coloring, ultra-violet inhibitors, etc. are added to the mixture. The melted pellets and the additives are thoroughly mixed and then the mixture is pushed (extruded) through a narrow slit in the film casting or blown through a die. The film comes out in a curtain or bubble, moving at several feet per second and falls onto rollers that cool each side of the film.
Virgin VS Regrind: What is the difference and why is it important?
Virgin poly pellets are brand new pellets – never been used before. Regrind pellets are made from melting down used poly and then made into pellets. This used poly can come from many different places and things such as plastic bottles, old tarps, plastic bags, etc. They come from just about anywhere from households to commercial sites during demolition.
While recycling is good for our planet, it’s not always the best option for poly sheeting. If you need to put plastic on the ground for landscaping to keep the weeds down, go ahead and use recycled plastic. On the other hand, if you’re putting in a vapor barrier or shrink wrapping something important enough to keep it in a weather-proof wrap, then you might not want a poly made from regrind. Regrind pellets could have dirt, moisture, or other foreign materials in them. This negatively affects the poly sheeting in the following ways:
- Color variations
- Cloudy or smoky poly due to specks in the material or incomplete washing
- Varied thicknesses in the same sheet of poly due to uneven melting of the pellet material
- Elongation at break is lower
- The film tends to be more brittle
When buying poly film, keep in mind what is its purpose? A vapor barrier must keep out vapor and it can’t do that if it has pinholes. An abatement plastic must not breach. When using heat shrink wrap, the material needs to be uniform in thickness or it won’t shrink correctly. If the film is brittle, you might have cracking. When putting up film to create barricades, you want to be able to see through it clearly.
One or more of these factors are to be considered when deciding which poly to buy.