All kinds of heat stabilizer heat discoloration Comment

Thermal stabilizers should preferably absorb both HCL, to eliminate the active site , the addition of a conjugated polyene chain , carbenium salt damage , etc. to prevent auto-oxidation , which does not produce the product of the catalytic degradation of PVC . The actual heat stabilizers have different functions due to exhibit different thermal stability characteristics , can be divided into early -type , long-term , intermediate -and versatile four . A ) cadmium , zinc soap is typical  Processing aid of early -type heat stabilizers , can quickly absorb HCL, and effectively substituted with carboxylate PVC unstable chlorine atom in the catalytic chain Cd, Zn , thereby effectively suppressing early degradation and coloring , but because of the consumption of fast and transformation products CdC12, ZnC12, but also off the HCL efficient catalyst PVC , PVC and thus lead to Chrolinated polyethylene  the degradation of the material suddenly vicious black , so poor long-term thermal stability. 2 ) barium, calcium soaps are typically long-term thermal stabilizers , absorption HCL function only and therefore can not inhibit coloring PVC , but the conversion product BaC12, CaC12 do not have catalytic activity , does not cause a sudden black PVC , long-term heat stability better. 3 ) fatty acids, organic tin are intermediate , both absorption HCL, can effectively replace with carboxylate unstable chlorine atoms PVC chain, and transformation products do not have catalytic activity.
 4 ) mercaptan organotin it Azodicarbonamide  has versatile features , while a variety of mechanisms can stabilize PVC, transformation products do not have catalytic activity , and therefore both excellent initial and long-term thermal stability effect.