What are the color issues after calcium zinc stabilizers replace lead salts?

During the processing of hard PVC products, the color problem is also a common and diverse issue that is relatively difficult to solve when the stabilizer changes from lead salt to calcium zinc stabilizer. Its manifestations include the following:
1. The replacement of stabilizers leads to a change in the color of the product. After the stabilizer is changed from lead salt to calcium zinc stabilizer, it is easy to find that the color of the product often tends to be greenish, and it is difficult to achieve a color change from green to red.
2. The color of the product inside and outside is inconsistent after using calcium zinc stabilizer. Usually, the external color is relatively positive, while the internal color tends to be blue-green and yellowish. This situation can easily occur in profiles and pipes.
3. The color drift of products during processing after using calcium zinc stabilizers. In the process of using lead salt stabilizers to process products, there may be some color deviation between different machines and at different times within the same machine, but the fluctuation range is relatively narrow. After using calcium zinc stabilizers, this fluctuation may become larger, and the impact of small fluctuations in raw materials and processes on hue may also be more pronounced. The author has personally encountered situations where customers use calcium zinc stabilizers to produce pipes and fittings, and pressure changes not only affect the color of the product, but also affect its performance. This change is much more sensitive than when using lead salt stabilizers.
4. The color issue of products during storage, transportation, and use after using calcium zinc environmentally friendly stabilizers. Hard PVC products using traditional lead salt stabilizers have relatively little color change during storage, transportation, and use. After being converted to environmentally friendly stabilizers such as calcium and zinc, there may be a tendency for the product to turn yellow and blue after standing. Some stabilizers may cause the product to turn red when used in products with high iron ion content in calcium powder.
The main reason for the above color issues is that the structure of calcium zinc stabilizers is relatively complex, and the thermal stability in the early, middle, and later stages is achieved through the coordination of multiple raw materials. Each component has a certain influence on the color of the product, and the combination of multiple components creates various possibilities. At the same time, market pressure has led some stabilizer manufacturers to subjectively use non compliant raw materials, which further exacerbates the complexity of the problem. To thoroughly solve the problem, it is not only necessary to analyze the specific problems, but also downstream PVC product processing enterprises need to carefully choose larger scale and reputable brand enterprises.
Key difference comparison: Lead salt stabilizers have been widely used due to their excellent electrical insulation properties and low price, but they have problems with high toxicity and dust pollution.