Migratory vs Permanent Anti-Static — Which One Your Part Actually Needs
Direct answer
A migratory antistat works by blooming to the surface and attracting a thin water layer that conducts charge away. It is inexpensive, it works within hours to days, and it stops working when the humidity drops or when the surface is wiped, washed or over-printed. A permanent antistat is a polymeric or conductive phase distributed through the part; it does not depend on ambient moisture, it does not wash off, and it costs several times more. The choice is decided by humidity, service life and surface handling — not by price.
Decide with four questions
- What is the minimum relative humidity in service? Below roughly 30 % RH a migratory antistat becomes unreliable. Cold-store, winter warehouse and desert export routes are the classic failures.
- Does the surface get printed, laminated, corona-treated or washed? Bloom interferes with ink and adhesive wetting and is removed by cleaning. Printing and anti-static bloom are in direct conflict.
- How long must the effect last? Migratory effect decays as the reservoir in the bulk is exhausted. For durable goods, permanent is the only honest answer.
- Is this static nuisance or ESD protection? Dust pickup and sheet cling are nuisance-level and migratory chemistry handles them. Protecting electronic components is a controlled surface-resistivity specification, and that is a different product class with a test method attached.
What goes wrong in practice
Migratory antistats are surfactants. They plasticise, they can reduce heat-seal strength, they can migrate into a food product, and in a multilayer film they migrate between layers rather than staying where they were compounded. In PP they bloom more slowly than in PE because crystallinity and free volume differ, so the same masterbatch at the same loading gives a different time-to-effect. Anti-block particles adsorb migratory antistat at the surface — a slip, anti-block and antistat package specified independently often underdelivers on all three.
Measurement, not opinion
Surface resistivity in ohms per square, measured at a stated temperature and humidity after a stated conditioning time, is the only meaningful acceptance criterion. A datasheet value taken at 50 % RH says nothing about performance in a 20 % RH warehouse. Where the requirement is contractual, agree the test method and conditioning before ordering.
What we supply
Allzone supplies permanent anti-static masterbatch for polyethylene. Delivery form and compatibility are stated on the product page from the verified product record; loading and resistivity targets are confirmed with the supplier at quotation.