Generally speaking, the yellowing of plastic products is caused by the aging or degradation of materials. Generally, PP is caused by aging (degradation). Due to the presence of side groups on polypropylene, its stability is not good, especially when exposed to light. Case. Generally add light stabilizer. As for PE, because there is no side group, it is not very yellow in the initial processing or use.
PVC will turn yellow, which is more related to the formula of the product. To put it bluntly, it is oxidation. The surface of some master batches is easy to oxidize, so it is necessary to perform surface treatment on the master batch. In addition to the poor additives and impurities in the system, which are mainly caused by aging, adding a suitable antioxidant system and anti-ultraviolet agent can improve the yellowing of PE and PP, but many hindered phenolic antioxidant systems themselves will bring slight Also, some antioxidant systems and anti-ultraviolet agents have a resistance effect, so be careful when using them. Adding polymer lubricants mainly allows it to form a flowable polymer fluoropolymer film on the wall of the machine, improving the extrusion processing performance, extrusion pressure and processing temperature of polyolefin resins, improving product quality, productivity, and reducing Production cost, reduce or eliminate melt fracture, reduce the scrap rate.