Statistics on patents in the field of metallocenes and alumoxanes at the European Patent Office

Abstract

Statistical analyses were carried out on patents that deal with metallocenes (see Editor’s note 1 1 Editor's note: A knowledge of the chemistry involved is not vital to an understanding of the data presented here, but for the non-chemists reading this, a metallocene is a chemical compound in which metal atoms are “sandwiched” between relatively planar hydrocarbon ring structures. An alumoxan is a compound with a long chain of alternating aluminium and oxygen atoms, with hydrocarbon side chains attached to the aluminium atoms. ) that can be used as catalyst (component) for the (co)polymerization of olefins, polymerization catalysts containing these metallocenes, polymerization processes employing these catalysts, polymers obtained by such processes, blends containing these polymers, and further uses of these polymers or blends containing them, and on patents dealing with alumoxanes. A comparison of the number of patents granted in the United States and by the EPO shows that in the US more than twice the number of patents have been granted in these technical areas as compared to Europe. In the field of alumoxanes, where about 20 patents have been granted, only one opposition has been filed. In the field of metallocenes, it was found that 61 oppositions have been filed at the EPO against about 200 granted patents, or about five times the overall figure for oppositions at the EPO, indicating a high prevalence of oppositions in this field. An analysis of the grounds for the oppositions revealed that all oppositions are filed at least on the grounds of lack of inventive step and/or lack of novelty. It turned out that the patents proprietary to different companies active in the field of metallocenes are not equally opposed, e.g. 60% of the patents granted to Exxon are opposed, whereas about 8% of the patents granted to Hoechst are opposed. Also the various companies in the field oppose a distinctly different number of patents. It was also found that in many opposition cases the same proprietor and the same opponent are a party. A family tree of US family members and their European relatives of patents dealing with metallocenes is discussed, showing further marked differences between the situation in the US and in Europe.