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2020

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01

An Explanation of the Safety of PVC Composite Stabilizers

　　PVC composite stabilizers are widely used, and concerns about their safety are increasingly attracting attention. When studying the safety of PVC composite stabilizers, three aspects should be taken into account: first, the safety of those who process the raw materials; second, the safety precautions for users; and third, the environmental safety of waste products. The safety precautions for processors can be addressed through measures such as liquefying, pasting, or granulating the stabilizers.
　　To ensure user safety, stabilizers can be made highly polymerized or prepared as reactive stabilizers to enhance their resistance to extraction. However, given that stabilization is a molecular-level chemical reaction, the above approaches may not be the most suitable ones. The best approach remains selecting stabilizers with inherently high safety profiles. When choosing a stabilizer, it is also essential to consider the safety of any chemical substances generated during the stabilization process—specifically, those formed by reactions between the resin and the stabilizer, or among different stabilizers themselves.
　　From the perspective of the safety of various stabilizers, cadmium-based stabilizers will soon be phased out. However, this transition will be a gradual one. One of the reasons is that most cadmium-free stabilizers tend to increase in cost by 10% to 20% when used, and cadmium-free stabilizers cannot be universally applied across a wide range of PVC compounds. Moreover, if the processing range is relatively narrow, auxiliary stabilizers often need to be added to compensate for their performance shortcomings. Currently, the performance of cadmium-free stabilizers has already reached the level of cadmium-based stabilizers. Calcium-zinc stabilizers are now experiencing rapid development.
　　Available in powder, paste, and liquid forms, as well as in standard-grade and non-toxic grades, second-generation calcium-zinc stabilizers have already replaced zinc-based tin and methyltin stabilizers in food and pharmaceutical packaging. Although lead-based stabilizers pose no safety concerns when used due to their low extractability, they do present environmental hazards. Given their low cost and high efficiency, many companies continue to use lead-based stabilizers. However, with the development of non-lead PVC composite stabilizers, lead salts are gradually being replaced by non-toxic, environmentally friendly stabilizers. As several countries impose bans on lead, lead-based stabilizers are now being phased out of the market.
　　In short, PVC composite stabilizers are moving toward safer, non-toxic formulations with promising prospects.

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