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 existence of side groups on polypropylene, its stability is not good, especially in the case of light. Generally, light stabilizer is added. As for PE, since there is no side base, there are not many cases of yellowing in general processing or early use. PVC will turn yellow, which is closely related to the formula of the product. To put it bluntly, it is oxidation. The surface of some masterbatches is easy to be oxidized, so it is necessary to carry out surface treatment on the masterbatches.
In addition to the bad additives and impurities in the system, I think they are mainly caused by aging. Adding suitable antioxidant systems and anti ultraviolet agents can improve the yellowing of PE and PP, but many hindered phenolic antioxidant systems themselves will bring about slight yellowing. In addition, some antioxidant systems and anti ultraviolet agents have resistance effects, so be careful when using them. Polymer lubricant is added to form a flowable polymer fluoropolymer film on the machine wall, improve the extrusion processing performance, extrusion pressure and processing temperature of polyolefin resin, improve product quality and productivity, reduce production costs, reduce or eliminate melt fracture, and reduce scrap rate.
1. There is a raw material called plasticizer in plastic products, which mainly plays an anti-aging role, but it will volatilize in the air, so when the plasticizer is reduced, the color will fade, and the elasticity of plastic will also decrease, which will make it brittle and yellow.
2. The yellowing of plastic boxes after production or use for a long time is due to the aging of the materials used, or it may be produced after degradation. The most serious phenomenon is some white plastic boxes, such as some white turnover boxes and plastic barrels.
3. The common reason is the aging of plastic products. The reason is that polypropylene has an upward side attack. Its stability is not very good, especially in the case of long-term drying.
4. Therefore, to make white plastics last longer, try to avoid strong light. If it is related to food, try to use transparent and colorless plastics. If you want to eradicate this phenomenon, you can add a certain amount of smooth stabilizer.
Post time: Sep-09-2022