Slip and anti-block masterbatches work together to control how plastic film behaves in high-speed handling, and research comparing different anti-block types shows the choice of anti-block genuinely affects how well it controls the slip agent it’s paired with. This page covers that research and how film friction is measured.
What is it?
Additive masterbatch in this category combines a slip agent with an anti-block additive to control the surface friction of plastic film. Per ASTM D1894-24, the standard for measuring the static and kinetic coefficients of friction of plastic film and sheeting, slip properties come from additives that “bloom,” or migrate to the film surface, lubricating it and making it more slippery.
Why should I use it?
- Its effect on film friction can be measured objectively using a standard test method, rather than judged by feel — see “What is it?” above.
- Research comparing anti-block types found a real performance difference in how well they control slip-agent migration — see Limitations.
How it’s used
In plastics and polymer applications, slip and anti-block masterbatches are compounded into polyethylene film to reduce surface friction (via the slip agent) while preventing layers of film from sticking together (via the anti-block additive), which the anti-block does partly by moderating how much of the slip agent migrates to the surface.
Limitations — when it isn’t the right choice
- Not all anti-block additives control slip-agent migration equally well, and the difference has a measurable effect on friction performance. A 2024 peer-reviewed study compared talc, natural silica, and synthetic silica anti-block additives paired with an erucamide slip agent in polyethylene monolayer film. After 7 days, the synthetic silica anti-block achieved a coefficient of friction as low as 0.095, with the lowest erucamide surface concentration (394 parts per million) among all the anti-block types tested. The study attributed this to synthetic silica’s smaller particle size and higher silica content, which “resulted in better friction properties which act as a good barrier to limit a migration of erucamide.” This means the anti-block additive isn’t just a passive filler added to prevent blocking — its particle characteristics directly affect how well the film’s slip performance holds up over time, and this should be evaluated rather than assumed equivalent across anti-block types.
