Mechanism of PVC Heat Stabilizer

1. Absorption and Neutralization of HCL, Prohibition of Automatic Catalytic Action

This type of PVC Stabilizer includes Lead based stabilizer, organic acid metallic soap stabilizer, organo-tin compound, epoxy compound,  phenolate and  metal thiolate, etc. They will react with HCL and prevent the effluent of HCL from PVC.  

2. Replacement of unstable chlorine atom in PVC molecule

If coordination bod occurs between organo-tin stabilizer and unstable chlorine atom, organo-tin stabilizer won’t replace the chlorine atom in ligand.

3. Addition reaction with polyene structure, destruction of the firmation of big conjugated system and reduction of coloring.

Unsaturated acid salt or ester have double bond. Diene addition reaction will occur between unsaturated acid salt or ester and conjugated double bond in PVC molecule, thus destroying its conjugated double bond and prohibit discoloring.

4. Capture of free base and prevention of oxidation reaction

Adding Phenolic heat stabilizer into PVC will prevent the effluent of HCL from PVC, because hydrogen atom free base contained in phenol will be coupled with free base contained in PVC molecule, forming a new matter which won’t react with oxygen, thus they have a certain heat stability. This type of stabilizer have one or more function.

Ideal PVC heat stabilizer should be multifunctional material or compounds of some materials, and they will have functions below:-

1. Replacing lively and unstable substituent base;

2. Absorbing and neutralizing HCL released from PVC processing and eliminating automatic catalytic decomposition of HCL;

3. Neutralizing or passivating metal ions and other harzadous impurity particles with the catalytic action to decomposition;

4. Preventing and shielding UV-light.