The study found that when the lead salt stabilizer is blended with other additives, it will react and generate a compound phosphate with extremely low solubility, so that the lead precipitation of the lead salt stabilized system is significantly reduced. For example, dibasic phosphate is a widely used in PVC and other plastics and as an absorbent for HCL. The reactants are mainly dichloride derivatives. When an additive is added to dibasic lead phosphate, the chlorinated The product of the reaction, lead dichlorodibasic phosphate, is converted into a complex, extremely insoluble salt.
This stabilizer has been listed as a lead salt stabilizer in the toxicity category by the US Environmental Protection Agency, and some other lead salts can also be modified in this way. This type of lead salt stabilizer has the characteristics of low solubility, low precipitation and low migration, and when it is blended with the polymer, the above properties are better. However, considering the toxicity of lead salt stabilizers, efforts are being made to develop such stabilizers with lower precipitation properties.
In addition, the use of dust-free composite lead salt stabilizer has an increasing trend, which provides convenience for PVC processing enterprises and reduces the lead salt dust pollution of processing enterprises.
Looking back at the market in the past few years, the development of heat stabilizers is very fast. Generally speaking, there are the following trends:
1. High stabilization efficiency
Improving the stabilization efficiency can not only prolong the service life of the product, but also improve the high temperature processability and reduce the amount of PVC stabilizer added. Especially in the development of some environmentally friendly stabilizers, new organic auxiliary stabilizers, such as phosphites, will be developed. It has excellent solubility and is used in polyolefins, polyesters and polycarbonates. In addition, it is necessary to improve compounding technology, create high-quality products, and develop compounding technology for weather resistance additives and light stabilizers. Develop metal-free stabilizers to reduce the use of metal soaps, especially zinc soaps.
2. Reduce costs
Improving the stabilization efficiency can undoubtedly reduce costs, but people are still making efforts to centralize and automate production, and develop a new variety of multi-functional and excellent PVC stabilizers to reduce costs. At the same time, it is necessary to make full use of cheap raw materials. For example, to develop antimony stabilizers instead of tin stabilizers, because of its excellent heat resistance, better heat resistance than tin stabilizers can be obtained with only a small amount of compounding.
Its only disadvantage is poor weather resistance. This needs to be overcome. At present, the sales of antimony products are increasing. The rare earth PVC stabilizer is a rookie in the stabilizer series in the world today. It is non-polluting, non-toxic, and has good light and thermal stability. We are very rich in rare earth resources, and research in this area should be strengthened. The composite rare earth-based PVC stabilizer recently researched and developed has a much better effect than a single component, and has broad application prospects.