Polyolefin Low Molecular Weight Extraction and Migration Testing
Polyolefin migration compliance requires batch-specific testing for low molecular weight hydrocarbons using accredited simulants, exact temperatures, and GC-MS.
Polyolefin Waxes
Meaning
Synthetic low molecular weight polymers derived from ethylene or propylene function as additives in many thermoplastic formulations. These polyolefin waxes reduce the friction between the melt and the metal surfaces of the processing equipment. They also help disperse pigments and fillers evenly throughout the resin matrix during compounding.
Processing Aid
Internal lubrication provided by these additives improves the flow of the material into thin wall sections of a mould. By reducing the melt viscosity, polyolefin waxes allow for lower processing temperatures and shorter cycle times. This efficiency helps reduce the thermal stress on the primary resin and prevents degradation.
It also minimizes the energy required to drive the screw in the injection unit. Lower torque requirements lead to less wear on the mechanical components of the machine over time.
Physical Properties
Inclusion of these materials can modify the surface hardness and the gloss of a finished part. Because polyolefin waxes have a higher crystallinity than many base resins, they can also influence the nucleation and crystallization rate of the plastic. This change affects the shrinkage and the dimensional stability of the part as it cools.
Application Scope
Selection of the correct wax depends on the desired balance between flow enhancement and mechanical strength. While they are useful in many applications, polyolefin waxes must be used at levels that do not cause surface blooming or interfere with bonding. Testing the material at the processing boundary ensures that the final product remains within specification.