Resolving Saturated Polyolefin Hydrocarbon Oligomer Interference in Mineral Oil Migration Dossiers
Polyolefin oligomer co-elution requires epoxidation clean-up and GCxGC deconvolution to prevent false mineral oil failures in migration dossiers.
Chemical Clean Up
Meaning
Chemical removal of degraded polymer residues and carbonized deposits from extrusion or injection moulding machinery restores bare metal surfaces. This maintenance procedure uses specialized purging compounds formulated with reactive agents that break down stubborn polymer chains. By targeting highly oxidized regions, chemical clean up dissolves the accumulated build-up without requiring physical disassembly of the barrel and screw.
The boundary of its efficacy lies in the level of mechanical wear, as it cannot repair physical damage to the metal components and is most effective when executed at regular intervals.
Purging Efficiency
Accumulated carbon deposits can flake off the screw during a run and create black specks in moulded parts. Standard mechanical purging often leaves pockets of old resin behind, but chemical clean up ensures the complete displacement of thermally sensitive materials like polyamides or polyesters. This thorough purging action reduces downtime during resin or color transitions and lowers scrap rates in subsequent cycles.
Material Preservation
High processing temperatures accelerate polymer degradation and lead to cross-linking of residual resin. Applying a chemical clean up compound at the end of a production run prevents the polymer from turning into a highly resilient gel during shutdown. This preventive step protects the screw surface from pitting and makes the startup sequence faster and more predictable.
Tooling Protection
Corrosive gases generated by the thermal decomposition of halogenated polymers degrade the internal surfaces of high-precision injection moulds. Regular chemical clean up of the extrusion barrel limits the formation of these acidic byproducts, ensuring that the melt entering the cavity is free of corrosive fractions. This action extends the working life of the tooling and preserves the surface finish of moulded parts.