Two additives quietly decide whether a film runs: slip and antiblock. Dose the slip too low and the film blocks and jams; too high and it over-blooms or hazes. Add antiblock and it pulls your slip out of balance. And if the film touches food, the whole package has to clear the FDA. Getting all of that right is most of the job in polyolefin film additives.
The short version: slip agents like oleamide and erucamide lower the coefficient of friction by blooming to the surface; antiblock fillers like silica or talc physically separate film layers so they do not stick. They interact, because antiblock adsorbs migrating slip, so the two are dosed together and balanced. Typical slip loading is 200 to 2,000 ppm in the finished film, and for food packaging oleamide and erucamide are cleared as release agents under FDA 21 CFR 178.3860.
Slip and antiblock do different jobs
It is easy to lump them together, but they solve two different problems. Slip lowers the coefficient of friction so surfaces glide; it is a migrating fatty amide that blooms to the surface. Antiblock stops the two film faces from sticking (blocking) under pressure; it is a fine inorganic particle, such as synthetic silica, diatomaceous earth, or talc, that creates microscopic bumps so the surfaces never fully contact. A film often needs both: antiblock to prevent blocking, slip to lower friction for machinability.
Dosage and loading
Slip agent is dosed at roughly 0.2 to 0.5 wt%, about 200 to 2,000 ppm, in the finished film, almost always added through a 5 to 10% slip masterbatch rather than neat, for even dispersion. Antiblock is typically dosed higher, often a few thousand ppm up to a couple of percent, depending on the particle and the blocking demand. Both are starting points; the right numbers come from running COF and blocking tests on your own film.
The slip-and-antiblock interaction
This is the part that trips up loadings. Antiblock particles have surface area, and migrating slip agent adsorbs onto that surface area instead of reaching the film face. So a film with antiblock needs more slip to hit the same coefficient of friction than a film without it. Raise the antiblock and you usually have to raise the slip to compensate. Treat slip and antiblock as a coupled pair, not two independent knobs, and re-test COF whenever you change either.
PE versus PP migration
Polymer choice changes the bloom. Polypropylene is more crystalline and runs hotter than polyethylene, which changes how fast and how far the slip agent migrates, so a loading tuned on LDPE will not behave identically in PP. Erucamide’s higher thermal stability is one reason it is often preferred in hotter PP and BOPP processing, as covered in oleamide vs erucamide.
Food-contact compliance
For food packaging the additives have to be cleared for food contact. In the US, fatty-acid amides used for slip and release in food-contact polymers fall under FDA 21 CFR 178.3860, formally titled “Release agents,” which lists permitted amides including oleamide and erucamide subject to the conditions in the regulation.
Treat that as a compliance starting point: confirm the exact listing and use conditions for your specific polymer and application, and check the equivalent regulations for any export market. This is a compliance fact, not a guarantee for your finished package.
Buying slip additives in bulk
RawSource supplies oleamide (CAS 301-02-0) and erucamide as prills, beads, or powder for plastics and polymer film, with CoA documentation, by the bag and pallet. Tell us your polymer, antiblock system, COF target, and food-contact needs, and request a sample to dial in the loading on your own film. The slip mechanism is in how oleamide works.
Frequently asked questions
How much slip agent do I use in PE or PP film?
Roughly 0.2 to 0.5 wt% (200 to 2,000 ppm) in the finished film, usually via a 5 to 10% masterbatch. The exact level depends on the antiblock, the polymer, and your COF target, so validate it on your own film.
What is the difference between slip and antiblock?
Slip lowers the coefficient of friction by blooming a lubricating layer to the surface; antiblock is an inorganic particle that physically separates film layers so they do not stick. They are different additives that are often used together.
Why does antiblock reduce slip performance?
Antiblock particles adsorb the migrating slip agent on their surface, so less slip reaches the film face. A film with antiblock therefore needs more slip to reach the same COF.
Is oleamide food-contact compliant?
Fatty-amide slip and release agents including oleamide and erucamide are addressed under FDA 21 CFR 178.3860 (“Release agents”) for food-contact polymers, subject to the conditions in the regulation. Confirm the specific listing and limits for your application before relying on it.
Does PE and PP need different slip loadings?
Often yes. PP is more crystalline and runs hotter than PE, which changes slip migration, so a loading tuned on PE will not behave identically in PP. Re-validate when you change polymer.
Editorial note. This article is general technical guidance for plastics and packaging professionals, written for industrial and professional use. Oleamide and erucamide here are industrial additives for plastics, not food, supplement, or consumer products. Regulatory references (21 CFR 178.3860) are stated as compliance facts to confirm for your specific application and jurisdiction, not guarantees; loading figures are typical ranges to validate by trial; the Certificate of Analysis governs the material you buy. Consult the product Safety Data Sheet (SDS) before use. RawSource makes no warranty, express or implied, and assumes no liability for use of this information.
