PVC stabilization with calcium-zinc compounds. Actual situation and prospects
Vladimir Bannikov, Country Manager Artem Smirnov, PVC and Additives Manager, DBH Osthandelsgesellschaft mbH Moscow Office (Germany)
Report points Technological practice of PVC processing shows that during recent years lead containing stabilizers are being actively substituted with calcium-zinc compounds. This trend is marked most strongly in European Union. European PVC market players have to take into account legislative EU regulations. The main documents specifying chemicals application particularly in PVC processing are REACH system (Registration, Evaluation, Authorisation and Restrictions of Chemicals) and Vinil-2010 agreement. The task of complete substitution of lead containing stabilizers with calcium-zinc ones in EU by 2015 is quite workable. And the substitution itself and increasing introduction of calcium-zinc compound can be considered as a global trend of PVC industry development. Along with environmental benefits there are technical reasons of calcium-zinc systems massive introduction. Such stabilizers are non-toxic, and their weather resistance is equal or exceeds lead-containing systems characteristics. Their processing conditions are almost the same with lead systems. There are no recycling problems. According to calcium-zinc compounds application opponents the main disadvantages of such systems are narrow processing window and increased mold contamination. However tests performed for modern calcium-zinc compounds show that those arguments are not exactly feasible. Specifically, static heat test results state that thermal stability values for PVC composites stabilized with both lead and calcium-zinc compounds within processing window are almost equal. Color changes (yellowness index YI) of specimens stabilized with calcium-zinc compounds within processing window indicate that such systems ensure equal or slightly exceeding color stability. Well-known at Russian and European markets distributor of raw material components for plastics processing, DBH Osthandelsgesellschaft mbH, provides calcium-zinc stabilizing compounds from Germany-based Additive Technology Greiz GmbH (ATG). Despite of ATG was established relatively not long ago, it accumulated the experience of Akcros Chemicals and then Allstab Chemicals, as ATG administrative and technical executives worked for these companies previously. During their existence the companies supplied large volumes of one-pack stabilizers to Russian market. ATG has sufficient production facilities and laboratory equipment for realization of existing technologies, supporting required production volumes and developing of new products. The company produces relatively wide portfolio of one-pack calcium-zinc stabilizers for various applications. Here it is necessary to state that exclusiveky the following kinds of calcium-zinc systems are produced under Akcrolite brand name: powder (P), granulate (G), flakes (F). For window profile production ATF offers various stabilizing compounds specifically developed with consideration for PVC window profile producers equipment types and technology features.