The difference between calcium zinc stabilizer and lead salt stabilizer

1、 Mechanism of action
Calcium zinc stabilizer: inhibits PVC decomposition through the synergistic effect of calcium soap and zinc soap, while absorbing HCl gas produced by PVC degradation. Its stability comes from the composite effect of multiple components (such as rare earths, hydrotalcite, etc.), which can inhibit the catalytic degradation of PVC by zinc ions.
Lead salt stabilizer: relying on the strong Lewis acidity of lead salt to neutralize HCl, and blocking the PVC chain decomposition reaction by displacing unstable chlorine atoms.
2、 Stability and environmental friendliness
Stability:
Lead salt stabilizers have better thermal stability, with outstanding initial coloring, lubricity, and long-term weather resistance.
The early stability of calcium zinc stabilizers is weak, but composite products such as rare earth calcium zinc significantly improve performance through synergistic effects, approaching the level of lead salts.
Environmental friendliness:
Lead salts contain heavy metal lead, which poses environmental pollution and human health risks, and do not comply with environmental regulations such as EU RoHS.
Calcium zinc stabilizers do not contain heavy metals, meet environmental requirements, and have resistance to sulfur pollution (such as not turning black in northern acid rain environments).
3、 Application Fields
Lead salt stabilizer: Due to its low cost and good electrical insulation, it was widely used in industrial fields such as cables and pipes, but gradually phased out.
Calcium zinc stabilizer: suitable for environmentally sensitive fields such as food packaging, medical devices, door and window profiles, and there is no risk of cross contamination when switching with lead salts and organotin stabilizers.
4、 Other differences
Density and Cost: Calcium zinc stabilizers have a low density (about 40% lower than lead salts), which can increase the amount of calcium carbonate used to reduce costs.
Lubrication: Lead salts have better lubrication, while calcium and zinc rely on auxiliary lubricants to regulate the plasticization process.
Anti zinc burning ability: Calcium zinc stabilizers require the addition of auxiliary components such as polyols and phosphites to inhibit the catalytic degradation of zinc chloride.
summarize
Although lead salt stabilizers have excellent performance, their environmental friendliness is poor. Calcium zinc stabilizers have gradually narrowed the performance gap through technological improvements (such as rare earth composites) and become mainstream environmental alternatives.