PVC stabilizer is one of the indispensable main auxiliaries for PVC processing. The number of PVC heat stabilizers used is small, but its role is huge. The use of heat stabilizers in PVC processing can ensure that PVC is not easy to degrade and is relatively stable. Heat stabilizers commonly used in PVC processing include basic lead salt stabilizers, metal soap stabilizers, organic tin stabilizers, rare earth stabilizers, epoxy compounds, etc. The degradation mechanism of PVC is complex, and the mechanism of action of different stabilizers is also different, and the stabilization effect achieved is also different.

Heat stabilizers commonly used in PVC processing include lead salt stabilizers, organotin stabilizers, rare earth stabilizers, metal soap stabilizers, etc.

Lead salt stabilizers can be divided into 3 categories:

(1)Simple lead salt stabilizers, most of which are basic salts containing PbO;

(2)Thermal stabilizers with lubricating effect, mainly neutral and basic salts of fatty acids;

(3)Composite lead salt stabilizers, and solid and liquid composite stabilizers containing synergistic mixtures of lead salts and other stabilizers and components.

Organotin stabilizers can be divided into 3 categories:

(1) Aliphatic acid salts, mainly referring to dibutyltin dilaurate, di-n-octyltin dilaurate, etc.;

(2) Maleate salts, mainly referring to dibutyltin maleate, bis(monobutyl maleate) dibutyltin, di-n-octyltin maleate, etc.;

(3) Thiolates, of which bis(thiocarboxylate) ester is the most used.

Rare earth heat stabilizers mainly include organic weak acid salts and inorganic salts of light rare earths lanthanum, cerium and neodymium which are rich in resources. The types of organic weak acid salts include rare earth stearate, rare earth fatty acid, rare earth salicylate, rare earth citrate, rare earth laurate, and rare earth octanoate.

Stearic acid soap heat stabilizers are generally prepared by saponifying alkaline earth metals (calcium, cadmium, zinc, barium, etc.) with stearic acid, lauric acid, etc. There are many types of products, each with its own characteristics. Generally speaking, lubricating stearic acid is better than lauric acid, and lauric acid is better than stearic acid for compatibility with PVC. In the PVC industry, there is rarely a single metal soap compound, but usually a compound of several metal soaps. The most common are calcium zinc soap stabilizers.