In the stabilizer processing often heard stabilizer, there are many kinds, lead salt, calcium zinc, barium zinc; Also divided into liquid, powder, etc. The kinds of different products added are different, even if the same products add different kinds of stabilizer. Often feel that stabilizer is a college question. So, can we not add it? Don't think about it. The answer is no. So, why must PVC heat stabilizer be added in PVC processing?
Pure PVC resins are extremely sensitive to heat, and slight thermal decomposition occurs when the heating temperature reaches above 90°C. When the temperature reaches 120°C, there will be a significant thermal decomposition reaction, so that the PVC resin color gradually deepened. The thermal degradation mechanism of PVC is very complex, but the essence of the thermal decomposition reaction of PVC is a series of reactions caused by the removal of HCl reaction, resulting in the fracture of the macromolecular chain and the failure of PVC resin. It is conceivable that under the high temperature of more than 100 degrees Celsius in production and processing, if there is no other material to help PVC stabilize, can PVC be smoothly processed and formed? The answer is definitely no. Therefore, the stabilizer is widely used in PVC processing.
It has been proved that adding heat stabilizer is an effective way to improve the thermal stability of PVC. It has the following functions: first, it replaces the active and unstable substituents; The second is to absorb and neutralize the HCL released in the process of PVC processing, eliminating the autocatalytic degradation of HCL; The third is to neutralize or passivate metal ions and other harmful impurities that catalyze degradation. Four is through a variety of forms of chemical reactions can block unsaturated bonds continue to grow, inhibit degradation coloring.
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