PVC heat stabilizers some of the important role

1 absorption and HCl, inhibit its catalytic automatically . Such stabilizers include lead salts , organic acids, metal soaps , organic tin compounds , epoxy compounds, amines, metal alkoxide and a phenolic salts and metal thiolate salt. They are available with HCl to de- HCl reaction inhibition PVC .
(2) replacement of PVC unstable allylic chlorine tin stabilizer  molecule or a tertiary carbon atom chlorine atom , inhibit de PVC. Such as organic tin stabilizer of PVC unstable molecule of chlorine ligand binding occurs , the ligand , organic tin substitution with an unstable chlorine atoms . 3 with the addition reaction of a polyene structure , damage the formation of a large conjugated system and reduce coloration . A salt of an unsaturated acid or ester containing double bonds , and the PVC molecules conjugated diene double bond addition reaction , thereby destroying the  Diethyleneglycoldibenzoate conjugated structure, and color.
 4 capture free radicals and prevent the oxidation reaction . Such as adding phenolic heat stabilizers can block off HCl, is due to give phenol H atom radical degradation of PVC macromolecules with radical coupling reaction with O2 to form a substance can not be , and has a thermal stability. Such thermal stabilizers may have one or several functions of both . Ideal PVC heat stabilizer should be a multi-functional substance , or a mixture of some materials , they can achieve the following functions:
1 replacement lively , unstable substituent such  titanium dioxide as attached to the tertiary Cl Cl atom or allyl chloride , to form a stable structure ;
(2) to absorb and process the PVC processing and release of HCl, HCl elimination autocatalytic degradation ;
 3 passivated on the degradation neutralized or catalytic metal ions and other harmful impurities ;
 4 by chemical reaction forms an unsaturated bond can block the continued growth inhibiting degradation coloring ;
5 The best protection against ultraviolet radiation shielding effect .