Internal Testing Replacing Accredited Reports in Food Contact Compliance Documentation
Replacing accredited food contact test reports with internal bench screening invalidates declarations of conformity and exposes importers to customs seizures.
Slip Agents
Meaning
Polymer additives that reduce the coefficient of friction of molded or extruded plastic films are integrated during the compounding phase. Known as slip agents, these amide-based chemicals bloom to the surface of the plastic after processing to form a thin lubricating layer. This layer prevents sheets of film from sticking together.
Migration Mechanism
Internal molecular structures of polyolefins are highly compatible with fatty acid amides at high melt temperatures, but this compatibility decreases as the plastic cools. Once the part solidifies, the slip agents slowly migrate to the outer surface because they are incompatible with the crystalline regions of the polymer. This blooming process is temperature-dependent and takes several hours or days to reach equilibrium.
The resulting surface layer is extremely thin and invisible to the naked eye.
Process Advantage
High surface friction causes plastic films to cling to metallic guiding rollers and tear during high-speed winding operations. Integrating slip agents lowers this friction, allowing the film to slide smoothly over manufacturing equipment without stretching or distorting. This lubrication reduces the torque required on winding motors and increases the overall production speed.
Smoother handling translates directly into higher yield and lower reject rates.
Downstream Effect
Modified surface properties can interfere with post-processing steps like corona treatment, printing, or adhesive bonding. If the concentration of slip agents is too high, the lubricating layer prevents inks and glues from adhering properly to the plastic surface. Food packaging lines must carefully balance the amount of additive to achieve easy opening of bags while maintaining good print quality.
Correct dosing is therefore a critical quality variable.