What is the purpose of lead salt stabilizers?

By capturing the HCl generated from the thermal decomposition of PVC, the catalytic degradation of HCl is prevented. Advantages of lead salt stabilizers: excellent thermal stability, long-term heat stability, good electrical insulation properties, good weather resistance, and low cost. I think it’s a chemical containing the metal element lead, so it’s classified under one category—lead salt stabilizers; there are also other types of stabilizers~~~ 　　

Lead salt stabilizers: What are the main components?

As far as I know, there is lead stearate, as well as zinc stearate, tin, and others.

Pure PVC resin is extremely sensitive to heat; when the heating temperature reaches 90°C or above, slight thermal decomposition occurs. As the temperature rises to 120°C, the decomposition accelerates, and at 150°C for 10 minutes, the PVC resin gradually changes from its original white color to yellow, then red, brown, and finally black. The decomposition process of PVC resin is a series of chain reactions triggered by the dehydrochlorination reaction, which ultimately leads to the breakage of the macromolecular chains. Lead stabilizers prevent the catalytic degradation caused by HCl by capturing it, which is produced during the thermal decomposition of PVC. Commonly used lead salt stabilizers include: (1) Lead trisulfate, with the molecular formula 3PbO·PbSO₄·H₂O; it is designated as TLS and is also referred to as trisalt. It is a white powder with a density of 6.4 g/cm³. Lead tribasic sulfate is the most commonly used type of stabilizer; it is generally used in combination with lead diphosphite, and a lubricant must be added due to its lack of lubricating properties. It is mainly used in rigid, opaque PVC products, with a typical usage amount of 2 to 7 parts. 　　(2) Lead diphosphite 　　The molecular formula is 2PbO·PbHPO3·H2O; it is designated as DL and is also referred to as diphosphate. It is a white powder with a density of 6.1 g/cm3. The thermal stability of lead diphosphite is slightly lower than that of lead trisulfate, but its weather resistance is better than that of lead trisulfate. Lead dithiophosphite is often used in combination with lead tribasic sulfate, at a dosage generally equal to half that of lead tribasic sulfate. 　　(3) Lead dibasic stearate  Codenamed DLS; it is less commonly used than lead trisulfate and lead diphosphite, but it possesses lubricating properties. It is often used in combination with lead trisulfate and lead diphosphite, at a dosage of 0.5–1.5 parts. 　　

The so-called lead salts are likely PVC heat stabilizers; their use seems to be largely prohibited due to the high toxicity of lead. Instead, more zinc, barium, tin, and other organic metals such as antimony are used, primarily to improve the heat stability of PVC during processing! ! !

It’s mainly restricted by the toxicity of lead; otherwise it would be very useful