Polyethylene Plastic PE Films Glossary

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CAMBER    As it applies to blown polyethylene film, camber is the tendency of any straight line to eventually curve. Also known as "dishing", any film which does not unroll perfectly straight will cause machinability issues in printing presses, bag machines, shrink tunnels and vertical form fill & seal VFFS machines.

CENTERFOLD   Film which is folded on one side and open on the other. Visit our Centerfold Polyfilm page.

centerfold "A" windcenterfold "B" wind


     see HAZE

While COF is usually measured film-to-film which makes sense for applications such as beverage shrink wrap, the interface is usually between film and stainless steel in VFFS vertical form / fill / seal, HFFS horizontal form / fill / seal and bakery bread applications. Stainless steel has a high surface energy of around 75 dynes, so it is reasonable to expect different results vis-à-vis film-to-film. Learn about the ASTM D 1984 test method.

What is high slip, medium slip and low slip?

The Flexible Packaging Association defines the ranges of slip (high, mediuim and low) and the kinetic coefficient of friction, when tested, film-to-film, in accordance with ASTM D 1984, as follows:

Surface                C.O.F.

1. Low Slip            Greater than 0.5

2. Medium Slip      0.2 to 0.5

3. High Slip           Less than 0.2

 COMONOMER    A monomer which is combined with a different monomer to make a polymer. A common example is EVA (ethylene vinyl acetate) / PEVA.