PVC foaming agent products are white, but they sometimes turn yellow when stored for a long time. What is the reason? Firstly, you need to determine if there is a problem with the selected foaming agent. PVC foaming regulator uses the foaming agent to decompose and produce gas that causes pores. When the processing temperature can reach the decomposition temperature of the foaming agent, it will naturally not foam. Different types of foaming agents have different decomposition temperatures, even if the same type of foaming agent is manufactured by different manufacturers, the decomposition temperature may not be exactly the same. Choose the PVC foaming regulator that is suitable for you. Not all PVC is suitable for foaming, so it is necessary to choose materials with relatively low polymerization degree for processing.
PVC foaming agent products are white, but they sometimes turn yellow when stored for a long time. What is the reason?
Firstly, you need to determine if there is a problem with the selected foaming agent. PVC foaming regulator uses the foaming agent to decompose and produce gas that causes pores. When the processing temperature can reach the decomposition temperature of the foaming agent, it will naturally not foam. Different types of foaming agents have different decomposition temperatures, even if the same type of foaming agent is manufactured by different manufacturers, the decomposition temperature may not be exactly the same. Choose the PVC foaming regulator that is suitable for you. Not all PVC is suitable for foaming, so it is necessary to choose materials with relatively low polymerization degree. Such materials have a low processing temperature, such as S700. If you want to use 1000 and 700, it may be different. The foaming agent may have already decomposed and the PVC has not yet melted.
In addition, there are other additives. The decomposition temperature of a normal foaming agent is higher than the processing temperature of PVC. If appropriate additives are not added, the result is that PVC decomposes (turns yellow or black) and ACR has not yet decomposed (foams). Therefore, it is necessary to add stabilizers to keep PVC stable (does not decompose at the trial temperature of AC). On the other hand, additives that promote AC foaming are added to reduce the decomposition temperature of AC and match it. There are also additives to make the foam pores small and dense, which is to avoid continuous large foam pores and reduce the strength of the product. Since the temperature is low and no longer turns yellow, I can confirm that your previous high temperature caused PVC to decompose and turn yellow. PVC decomposition is a self promoting reaction, which means that the decomposed substances promote further decomposition. Therefore, it is often seen that it is okay if the temperature is not high, but if the temperature is slightly high, it will decompose in large quantities.
Post time: Jan-08-2024
