Hydrotalcite is a white mineral having a layered structure found in nature with a general chemical formula of Mg6Al2(OH)16CO3.4H2O. PVC is decomposed during processing from heat and the shear stress effects, and is decomposed by the effect of UV rays while it is in final product form, resulting in the Cl in its structure being released. Cl, which is released into the medium in the form of an HCl gas, may cause the PVC first to turn yellow and then to burn out. The most important functions expected out of the stabilizers is to chemically react with the HCl which has been released. Hydrotalcites are very effective in PVC stabilization because they are very good acid scavengers due to their exceptional anion-exchange properties. Hydrotalcites have greatly enhanced the performance of Ca/Zn-based stabilizer systems, due to their features of environmentally friendliness and non-toxicity. They particularly have a major share in the development of stabilizers used in the production of rigid PVC window profiles and flexible PVC automotive cables with high service temperatures. At Semfa Group, we have 2 types of hydrotalcite products.
AS-01 is a synthetic hydrotalcite based on Magnesium and Aluminum and developed as an acid scavenger in PVC applications. It is primarily used as an acid scavenger in the polymer industry (e.g., PVC, PE, PS) contributing to the improvement and the protection of the properties of polymeric materials. Hydrotalcite is also used as an antacid to neutralize the gastric acid in the pharmaceutical industry, in addition to its usage in many applications.
AS-04 is a synthetic hydrotalcite with a double-layered hydroxide structure based on Magnesium, Zinc and Aluminum. It contains charge balancing anions in its interlayers and is especially developed for use in cable and window profile applications.