Melt Shear History and Contaminant Catalyzed Scission in Post Consumer Polyolefin Silo Blends
Deactivate metal catalysts and neutralize acid traces with targeted additives to stabilize viscosity drift and optimize landed cost per good recycled part.
Hydrotalcite Acid Scavengers
Meaning
Synthetic mineral additives neutralize acidic residues in polymer resins to prevent degradation and equipment corrosion. Incorporating hydrotalcite acid scavengers into the polymer compound protects the plastic matrix from being degraded by catalyst residues. These additives are particularly useful in polyolefin resins manufactured with transition metal catalysts.
Their high thermal stability makes them suitable for high-temperature extrusion.
Resin Protection
Acidic compounds can be generated from catalyst residues during extrusion. When hydrotalcite acid scavengers are present, they neutralize these acids within their layered crystal structure.
Quality Control
The use of acid scavengers affects the optical properties of the finished film or moulded part. By adding hydrotalcite acid scavengers, compounders avoid the yellowing that typically occurs when resins are exposed to heat during processing. This aesthetic preservation is important for food packaging films and medical devices where clarity is required.
It ensures that the plastic remains colorless and transparent throughout its service life. This performance is verified by measuring the yellowness index of the extruded sheets.
Mould Integrity
Corrosive fumes from acidic residues can damage the polished steel surfaces of injection moulds during production runs. Including hydrotalcite acid scavengers in the resin compound reduces the frequency of mould maintenance by preventing acid attack. This protection extends the life of the injection mould and preserves the glossy finish of the moulded parts.
Moulders can run longer production cycles without having to stop and clean the tooling.