Bulk Packaging Verification Protocols against Pre Production Test Certificates
Verify bulk plastic packaging against pre-production certificates using lot-specific AQL dock sampling, ATR-FTIR screening, and full DoC dossier traceability.
Slip Additive Migration
Meaning
Diffusion of low-molecular-weight friction-reducing agents from the bulk resin to the surface of a moulded part or film. Packaging manufacturers incorporate these additives to reduce the surface friction of plastic films, improving handling and winding. This process is highly dependent on temperature and time.
Surface Accumulation
This migration occurs because the slip additive has limited solubility in the polymer matrix, causing it to move to the surface over time. Once on the surface, the additive forms a thin lubrication layer that reduces friction and prevents film blocking. Quality teams monitor slip additive migration to ensure consistent surface friction across production batches.
Environmental Impact
High storage temperatures can accelerate the migration, leading to an excess of additive on the part surface. If the concentration is too high, the surface becomes oily, which can cause feeding and handling issues on automated packaging lines. Processors must control the additive concentration and storage conditions to prevent this.
Secondary Bonding
The presence of migrated slip additive on the surface can interfere with downstream processes like printing, laminating, or gluing. Inks and adhesives cannot wet and adhere to the low-friction surface, resulting in poor print quality and bond failures. Moulders must clean the surface or perform surface treatments like corona or plasma before applying these secondary processes.