Metallocene catalysts, euphorically greeted by many as a "quantum leap in the synthesis of plastics", are now becoming established in commercial plastics production. The metal complexes, in contrast to the traditional Ziegler-Natta catalysts, allow specific structuring of the polymer chain, and thus allow the property profile of the plastic to be precisely controlled over a broad range. Properties such as rigidity, hardness, impact strength, transparency and resistance to heat and chemicals, can be improved. Metallocene catalysts are currently being used primarily in polyolefin production, and it may well be possible in future to manufacture plastics with as yet unknown property combinations.

The downside to it all are the higher costs of metallocene plastics and their conversion into end-products. Cooling problems and greater wear on the machines make life difficult for converters. Plasteurope.com will deal in more detail with this problem in later issues.

Nevertheless, metallocene catalysts are expected to grow considerably in the next few years. In the opinion of the international research company Frost & Sullivan the economic success of these materials will depend on the fast availability of products with a favourable cost-to-benefit ratio, which will allow processors to introduce new product types based on metallocene polyolefins. In its latest study, "The European market for metallocene polymers (Report 3465G)", Frost & Sullivan puts the total European market for polyolefins and related products in 1996 at 15.3m t. Polyethylene accounts for the lion's share with 63.5%. The small share of metallocene polyolefins is expected to rise from 0.1m t in 1997 and an estimated 0.2m t in 1998 to 2.4m t by the year 2004.

According to the market research company Phillip Townsend Associates, Inc., polyethylenes (HDPE and LLDPE) based on metallocene catalysts have established themselves on the world markets over the last two years, with the exception of the eastern and central Europe region. The study, entitled "Metallocene Polyethylene – 1997: An Update of Advancements, Players, and Market Impact", forecasts increased market penetration of metallocene plastics in the near future, particularly with extruded LLDPE and, to a lesser extent, with injection moulding grades of HDPE and LLDPE.

By year-end 1998, Townsend is expecting production capacities for metallocene to grow to 1.3m t in North America, 750,000 t in Europe and 400,000 t in Japan. Worldwide demand is estimated at 600,000 t. For the year 2001, global consumption is estimated at 3.5m t. North America will head the list with 1.875m t, followed by the Asia-Pacific countries with 740,000 t, western Europe with 625,000 t and Japan with 300,000 t. – Further details from Phillip Townsend (with graphs): PIE-No. 41986.

Up until 1994, only Exxon and Dow produced metallocene. There are currently 15 companies manufacturing metallocene-PE on a commercial or semi-commercial basis. At least ten other companies are working in this area of technology, according to Townsend. Of these 25, Townsend regards Dow, Exxon and Mitsui Chemicals as the leading players in metallocene catalyst and process technology. The majority of these raw material producers are concentrating on the development of low-pressure processes, while others are focusing on high-pressure autoclave processes.

Frost & Sullivan, too, describes Exxon, which has a joint venture with Union Carbide under the name Univation Inc., and Dow, which is cooperating with BP Chemicals, as "established suppliers of complete technology packages"(see Plasteurope.com 15, 1996). Nevertheless, in these alliances, the partners remain independent as manufacturers of polyolefins. The two German plastics producers BASF and Hoechst have taken a different route by setting up a joint venture under the name Targor in the PP sector. This jv will look after the licensing of BASF processes and, if the situation arises, will also establish production facilities for metallocene.

Improving the polymer properties (i.e. processing performance) is one of the main concerns of raw material suppliers. Dow and BP have announced the development of a metallocene polymer which can be processed like low-density polyethylene. Work is also being stepped up on improving the catalyst formulation, whereby the emphasis is on harmonising the mixing of catalyst and co-catalyst and improving performance to minimise catalyst consumption and maximise life expectancy and activity. Despite the increasing popularity of metallocene catalysis, Ziegler-Natta polymerisation will continue to play an important role for many years, according to Frost & Sullivan. Metallocenes will be an integral part of polyolefin manufacture by the middle of the next decade; other modern catalysts without metallocene will extend the spectrum.