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Why Is Your Calcium-Zinc Stabilizer Always "Unstable"?
创建于11.11
PVC products just off the production line often experience unexplained yellowing and embrittlement during upstream processing or storage. This problem has long plagued industry technicians: why do carefully formulated calcium-zinc stabilizers frequently fail in the mid-to-late stages? The answer usually points to an industry chronic issue — the "zinc burning" phenomenon.
As a professional R&D and production enterprise of heat stabilizers, Deyan deeply analyzes the mechanism of "zinc burning" and shares root-cause solutions today.
1. The Essence of "Zinc Burning": A Chain Reaction of "Good Intentions Leading to Bad Results"
To understand zinc burning, we first clarify the working principle of calcium-zinc stabilizers: during PVC processing under heat, zinc soap, as the core component, can quickly capture HCl released from PVC molecular chains, providing excellent initial stability.
The core problem lies in the by-product zinc chloride (ZnCl₂): as a Lewis acid, ZnCl₂ has extremely strong catalytic activity. It accelerates the breakage of PVC molecular chains and the dehydrochlorination reaction, forming a vicious cycle. With the progress of processing, ZnCl₂ accumulates continuously, and the catalytic reaction intensifies exponentially. Eventually, the material suddenly turns black and degrades in the mid-to-late stages, similar to an "avalanche" effect.
In short, the essence of zinc burning is that after the stabilization reaction of zinc soap, its by-product is transformed into a "catalyst" for PVC degradation.
2. Solutions: The Key Lies in "Trapping" ZnCl₂
The core solution is not to prevent the reaction of zinc soap, but to timely control, neutralize or inertize the generated ZnCl₂, blocking its catalytic effect.
Traditional schemes mostly use auxiliary stabilizers such as calcium soap to slow down the consumption of zinc soap by neutralizing HCl. However, this method has limited efficiency, especially in transparent products or high-demand formulations, making it difficult to achieve complete inhibition.
3. Deyan Calcium-Zinc Stabilizers: Efficiently Inhibit Zinc Burning
The specific advantages of Deyan calcium-zinc stabilizers are as follows:
Efficient chelation to cut the reaction chain: It firmly binds ZnCl₂ through chelation, making it lose catalytic activity. This fundamentally blocks the zinc burning chain reaction and significantly extends the overall thermal stability cycle of products.
Excellent compatibility with no blooming risk: It has good compatibility with PVC resin and various additives, does not affect product transparency, and avoids undesirable phenomena such as blooming and stickiness.
Environmental protection and safety with upgraded comprehensive performance: The product is a white odorless powder, free from sulfurization pollution risks. While solving the zinc burning problem, it can optimize plasticization effect and improve product mechanical properties, making it an excellent alternative to lead-containing additives.
Conclusion
Zinc burning is not an incurable industry problem. Through in-depth analysis of its mechanism, we can effectively address the pain point of "insufficient mid-to-late stage stability" of calcium-zinc stabilizers and fully release their stable performance.
Deyan has been deeply engaged in the R&D and production of PVC heat stabilizers for more than 20 years. Its thiol methyl tin and calcium-zinc stabilizer series products have excellent thermal stability and balanced lubrication effect, which can fully meet the core needs of manufacturers for processing technology and product mechanical properties.
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