Core Advantage
1. It has outstanding environmental protection and non-toxic characteristics
Calcium-zinc stabilizers do not contain heavy metals such as lead and cadmium, and comply with international environmental protection regulations such as the EU RoHS and REACH. Its products can be used in fields with high safety requirements such as food packaging and medical devices, avoiding the biological toxicity risks of traditional lead salt stabilizers.
2. Excellent thermal stability
Calcium-zinc stabilizers can efficiently absorb HCl released during PVC processing through the synergistic effect of hydrotalcite (layered bimetallic hydroxide) and polyols, thereby inhibiting degradation reactions. Experiments show that the thermal stability time of high-quality calcium-zinc stabilizers can reach over 100 minutes, and the temperature resistance performance of some formulations is 15℃ higher than that of traditional lead salts.
3. The processing convenience is remarkable
The powder dosage form (accounting for more than 80%) is convenient for precise measurement and mixing, and simplifies the production process. Meanwhile, its internal lubrication characteristics can reduce the addition amount of external lubricants and lower the risk of precipitation. For instance, solid calcium-zinc stabilizers can maintain the fluidity of the melt in the processing of hard pipes, and the surface finish of the products is superior to that of the lead salt system.
4. Material compatibility improvement
Some formulations enhance the bonding force between the resin and the filler through coupling technology, allowing for the addition of more inexpensive fillers such as calcium carbonate, which can reduce the material cost by 5-10%.
Application Limitations
1. The processing technology window is relatively narrow
The calcium-zinc system is highly sensitive to temperature. If the processing temperature fluctuates by more than 5℃, it may cause initial discoloration (yellowing) or zinc burning. For instance, the production of rigid PVC pipes requires strict control of the screw speed and die head temperature, and the process debugging cycle is 30% longer than that of lead salts.
2. Insufficient long-term stability
Some low-end products are prone to discoloration in the later stage when exposed to ultraviolet rays or damp heat, and the anti-aging property of the products is weaker than that of the organotin system. Studies have shown that the addition of β -diketone additives can improve this defect, but the cost increases by more than 20%.
3. High dependence on lubricants
To balance the plasticizing speed, additional external lubricants such as oxidized wax and PE wax need to be added. Excessive use may lead to carbon deposits in the mold, and the mold cleaning cycle can be shortened to 50% of that of the lead salt system. For example, when processing transparent products, special liquid calcium-zinc stabilizers should be selected to prevent precipitation.
4. Trade-off between Cost and Performance
The price of high-end calcium-zinc stabilizers (such as those containing microcrystalline 4A molecular sieves) reaches 22 yuan per kilogram, which is 3 to 5 times that of lead salts. Although the cost can be reduced by increasing the amount of filler, the mechanical properties of the product may be sacrificed.
Development Outlook
At present, calcium-zinc stabilizers have occupied 35% of the global PVC additive market share, and the domestic market size has exceeded 1.2 billion yuan. Future trends include: developing nano-hydrotalcite composite technology to enhance thermal stability, optimizing the synergistic formula of polyols and phosphite esters to extend the mold cleaning cycle, and reducing the cost of new additives such as silver nanowires through freeze-drying processes. With the tightening of environmental protection policies, the penetration rate of this material in fields such as architectural profiles and medical catheters will continue to increase.