PVC is one of the most produced plastic products in the world. PVC is a white powder with an amorphous structure with a small degree of branching and poor stability to light and heat. Due to the extremely poor processing stability of PVC, the melting process is as high as 160°C, and PVC decomposes when the temperature reaches 140°C, so PVC resin must be processed and produced by melting and plasticizing through modification treatment.

The role of heat stabilizers

In the process of resin processing, prevent or inhibit the removal of HCl and the discoloration caused by the removal of HCl.
During the effective use period of the product, it maintains sufficient thermal stability and slows down the degradation caused by heat, light, and prolongs its service life.
The mechanism of heat stabilizer

1. Absorb the HCl produced during the degradation of PVC;

2. Replace the unstable allyl chloride atom or tertiary carbon chlorine atom in the PVC molecule to inhibit the removal of PVC and HCL;

3. React with free radicals to stop the transmission of free radicals;

4. Addition reaction with conjugated double bonds to reduce coloration;

5. Inhibit the oxidation of PVC;

6. Passivation of metal ions that have a catalytic effect on removing HCl.

Classification of heat stabilizers

According to their roles, they can be divided into three categories:

Main heat stabilizer (lead salt, metal soap, organic tin, etc.)
Auxiliary heat stabilizer (epoxy compound, phosphite, polyol, etc.)
Composite stabilizer composed of primary and secondary stabilizers