Slip additives
Slip is when polymeric films slide parallel over each other. Slip is a surface effect. Slip is quantified via the coefficient of friction (COF). If films have a high COF, individual film layers have a high surface friction and tend to stick together in stead of sliding over one another. The films do not ‘slip ’. This phenomenon typically makes the handling, use and conversion of films rather difficult. It can result in decreased line speeds (lower productivity) and/or wrinkled fiiflm (higher waste). In order to overcome this issue, slip agents are added.

Influencing the slip effect
In general , slip additives should always be tested in the presence of the entire additive package in the film. Various co-additives influence the performance of slip agents . When combining slip additives and anti-block additives, there can be an interact ion where increasing one additive actually enhances the effect of the other additive. The slip effect is influenced by the slip additive concentration. Increasing the concentration will reduce the COF until an equilibrium state is obtained. At (too) high concentrations, slip additives plate onto process equipment and negative interactions with adhesion and lamination operations might be observed.
Further, an increased film haze will likely be observed. The slip properties can also be improved by:
 + decrease in film thickness
 + antiblocking agents (low concentration)
 + fast migrating substances (e.g. antifogging agents and selected antistats provide a carrier effect).