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Coefficient of friction (COF) changes after converting

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Q. Why might the COF of my polyethylene film be different after converting?

A. COF (coefficient of friction) is a measurement of resistance caused by the friction between two moving surfaces. COF is primarily measured as film-to-film and is often referred to as slip.

There are several ways in which converting a polyethylene film could change the film’s COF or slip.

Simply re-heating the film can cause the slip to migrate back into the film. Inks can block slip migration and adhesives can scavenge slip. Film-winding tensions can also affect the migration of slip through films, so excellent tension control during winding is critical.

Good communication with your suppliers is essential. There are several ways that each supplier (film, adhesive, ink, etc.), in this instance, might be able to change the outcome. Simply making sure that your suppliers know what your packaging goals are can help to ensure that the final converted product meets specifications.