Development of Single-Site New Olefin Polymerization Catalyst Systems Using MgCl_2-Based Activators:MAO-Free MgCl_2-Supported FI Catalyst Systems

摘要

MAO-free new single-site catalyst systems have been developed for olefin polymerization,which are comprised of bis(phenoxy-imine) Ti,Zr,or V complexes (Ti-,Zr-,or V-FI Catalysts) and MgCl_2-based compounds.These new catalyst combinations are highly active single-site (Ti-FI Catalysts),exceptionally active (Zr-FI Catalysts),or highly active,thermally robust,single-site (V-FI Catalyst) catalysts for ethylene polymerization.The catalysts can display higher catalytic performance (i.e.,catalytic activity,stereoselectivity,thermal stability) than those activated by the well-established MAO activators.In addition,these catalysts are supported,and thus possess a technological advantage vis-a-vis control over polymer morphology,which is essential for commercial application.Therefore,the application of MgCl_2-based compounds capable of working both as an activator and a support for non-metallocene complexes provides a conceptually new strategy for the development of high-performance supported single-site catalysts.