BP adds metallocene catalyst technology to polyethylene process

BP will offer its new polyethylene production technology for licence worldwide. The technology combines the use of metallocene catalysts with BP's Innovene gas phase polyethylene process.

The technology offers high performance linear low density polyethylenes (LLDPEs) free from the processing difficulties associated with existing metallocene-catalysed polyethylene. The announcement follows agreement between BP and The Dow Chemical Company and between BP and Univation Technologies, LLC, the ExxonMobil/Union Carbide joint venture, regarding earlier metallocene catalyst research.

The agreement is part of a wider deal under which BP will acquire Dow's interest in the technology developed jointly by the two companies. BP now has the rights to develop and license constrained geometry metallocene catalyst technology for gas phase polyethylene processes.

BP and Dow had been collaborating to develop catalysts based on Dow's INSITE metallocene technology for use with BP's Innovene gas phase polyethylene process since 1995, but the active collaboration ended in 1999 when Dow announced plans to merge with Union Carbide, leaving BP to pursue the development alone.

First commercial-scale trials of the jointly developed Innovene metallocene technology were completed in 1999 at BP's joint venture PT Peni site at Merak, Indonesia, and BP has continued to develop and prove the technology at full scale. This work has demonstrated stable and prolonged operation of the catalyst at design rates with the need for only minor plant modifications.

BP plans to introduce the technology commercially on its own plants in Europe once decisions on the appropriate manufacturing location are made. These will follow completion of the commissioning of its new 350,000 tonnes per year polyethylene plant at Grangemouth, Scotland, and the completion of BP's acquisition of Bayer's 50 per cent share of the companies' Erdoelchemie joint venture.

The Innovene process for the production of polyethylene (LLDPE and HDPE) operates at low temperature and pressure. Polymer particles grow in a fluidised bed reactor where the fluidisation gas is a mixture of ethylene, comonomer, hydrogen and nitrogen. Unreacted gas is cooled, compressed and returned to the reactor, maintaining the growing polymer particles at the desired temperature.

The process allows a range of both broad and narrow molecular weight LLDPE and HDPE applications to be covered, including blown and cast film, injection moulding, blow moulding, rotational moulding, pipe, and wire and cable.

The Innovene metallocene technology currently targets the production of high performance blown and cast film markets. Its constrained geometry catalyst, when combined with selective long chain branching and very narrow molecular weight distribution, results in products exhibiting mechanical properties matching or exceeding those of current conventional metallocene products. However, the Innovene metallocene products also have substantially superior processability, sealability and optical properties.