Meaning
Chemical degradation occurs when the fatty acid amide slip agent reacts with atmospheric oxygen or peroxide catalysts at elevated temperatures. Erucamide oxidation reduces the concentration of the active lubricant available to migrate to the film surface. This chemical transformation converts the slip additive into polar reaction products that lack the migratory capability of the parent molecule.
The resulting loss of surface lubrication triggers an increase in the coefficient of friction during downstream film handling.
Degradation Kinetics
High temperature processing environments promote the formation of hydroperoxides and ketones within the slip additive structure. Such reactive intermediates further decompose into non-functional fragments. Moulders encounter this problem when residential time in the hot runner or extruder barrel exceeds the stability threshold of the erucamide.
Excess shear heat compounds the rate of breakdown. Recycled resin streams contain high levels of already oxidized species that consume the antioxidant package before the primary slip agent performs its function.
Moulding Consequences
Slip performance depends on the maintenance of a consistent concentration of the unreacted additive within the polymer matrix. When erucamide oxidation happens inside the melt, the surface of the finished part remains tacky because the blooming mechanism fails. Finished goods demonstrate erratic slip properties that vary across the surface of the same production lot.
Automated packaging lines reject these components due to their inability to feed correctly through friction-driven guides. Surface adhesion forces rise sharply as the additive level drops below the saturation point.
Tooling Interaction
Cooling channel efficiency dictates the rate at which the surface temperature drops after the material exits the nozzle. Efficient heat transfer restricts the time window where oxidation remains active. Practitioners monitor the vent deposits on the mould face because oxidized erucamide residues often combine with other low molecular weight fractions to form sticky gummy buildup.
This accumulation alters the release properties of the cavity and forces frequent cleaning cycles that disrupt production schedules. The presence of oxidized slip residues limits the effectiveness of subsequent surface treatments like corona discharge.
