One of the ubiquitous synthesiser wizards of the 1980s said it best: we are living in the plastic age. A novelty only 40 years ago, these man-made materials now pervade our lives in almost every way imaginable. But while their versatility is a godsend both to us and to the companies that use them, it is creating problems for the companies which make the plastics themselves.
Plastics are, in general, quite simple substances. The products which surround us every day – the bulk or ‘commodity’ plastics- are relatively easy to make, and every producer makes a more or less indistinguishable product. Profit margins are, therefore, low. And as the industry develops, so more of its products slip from the high-value speciality end of the spectrum to become low-margin commodities. The polycarbonate market, for example, has been transformed: once a hard-wearing product aimed at niche markets, it’s now familiar as the material for compact discs and casings at the trendier end of the PC market.
Plastics producers are therefore attempting to find ways to boost their profitability. At one of the world’s largest, the German chemicals giant BASF, the strategy involves using the company’s extensive R&D resources to capture the high-margin end of the market. Traditional speciality areas are steadily becoming commodities, explains Fred Baumgartner, head of BASF’s engineering plastics division. ‘The reason for this is the rising performance level of products in standardised areas, such as the automotive sector,’ he says. The chemical industry is, in part, a victim of its own success here: the steadily improving performance of of plastics, and of the components made from them, has driven down margins. The profit potential of plastics designed for small- to medium-volume applications is slowly but surely falling away.
‘For this reason our expansion efforts are concentrating more and more on application-based R&D,’ says Baumgartner. ‘In collaboration with customers, our experts are opening up new applications for our products.’
‘Our customers’ expectations of our plastics are not only very specific, but frequently differ greatly from one another,’ says BASF Polyurethanes president Jean-Pierre Danis. ‘This presents new challenges on an almost daily basis.’ But the rewards are considerable – speciality products are largely immune from business cycles. And if the products are tailored to a company’s specifications, they also provide near-guaranteed sales.
Part of the strategy here is to use the company’s R&D infrastructure to ‘raise the bar’ on technology. In-house process technology development has long been a strength of BASF, whose labs use large-scale modular equipment known as ‘mini-plants’ to scale up experimental processes from benchtop scale to production volumes.
Because of these, the company can often bypass completely the ‘pilot plant’ level of process development, allowing it to bring new processes on line years earlier than would be possible by more conventional development routes. The company uses thistechnique to patent techniques and products ahead of its competitors,giving it exclusive access to the markets for which it has developed them.
Ecoflex, BASF’s biodegradable polymer range, is an example of this. At its most basic, Ecoflex is a copolymer made from three components familiar from the production of other plastics: adipic acid, butanediol and terephthalic acid. When the groups of atoms at either end of these compounds link together, they form structures which are also found in nature. Because of this, they can be broken down by enzymes which are part of the biochemistry of many micro-organisms found in soil. The net result is a plastic which is robust and hard-wearing – until it’s buried. After three months in the ground, the micro-organisms convert in into their ownbiomass, carbon dioxide and water. The degradation process is as fast as for natural starch, BASF estimates.
One use for Ecoflex is in agricultural coverings – farmers can use large sheets of the polymer to protect entire fields of delicate crops, such as lettuces, from frost, then just plough the sheets into the field after harvest. But the process technology available to BASF has allowed it to let the polymer branch out – literally.
The properties of polymers stem from the arrangement of their components, and the key to the development of new polymers is an understanding of how different arrangements can give rise to new properties. Ecoflex can be processed with the same systems that BASF uses for its most basic plastic, polyethylene; and even though its PE business was placed into the Basell joint venture with Shell last year, the German firm has retained its process technology.
In the case of Ecoflex, the modification process is fairly simple – the properties of the polymer depend on the length of the molecular chains of the three components and the degree of ‘branching’ along their length. This variable composition allows Ecoflex to be used as a molecular construction kit for customised products. Regardless of whether they are formed as flexible films or sturdy containers, they are always biodegradable.
This makes the Ecoflex family of products rich in potential. For example, the polymer is resistant to greases and oils, and is already in use as a barrier additive for food packaging. But these properties could also make it useful for more arduous duties, such as the filters inside extractor hoods. These are generally made frompolymers such as polyester which, although they are recyclable to a degree, are not biodegradable.
Another example of BASF’s capabilities in adapting processes and products can be found in the walls and ceilings of Germany’s latest examples of experimental housing. Spurred on by an energy efficiency-focused government, the company is developing what it calls a ‘three-litre house’ – meaning that it consumes just three litres of oil per square metre of living space per year to heat. As part of this, it has developed a new insulation material called Neopor.
Neopor is based on Styropor, BASF’s expanded polystyrene sheeting, but two differences are immediately obvious – the sheets are grey instead of white, and considerably thinner. This is because the matrix of the sheets incorporates flakes of granite which, according to Werner Praetorius, the president of BASF’s styrenic polymers section, make the sheets ‘almost impervious’ to heat.
Neopor boards can be 20% thinner than normal polystyrene while providing the same insulation. This means the material can be used in older buildings, where space for insulation material was not originally specified, as well as in new buildings.
Other companies are charting their own routes toward similar goals. In the US, for example, DuPont is eschewing the specialities route in favour of a more time-tested method: using process technology to drive down its costs for making a bulk polymer,polyethylene terephthalate, thereby maximising profits.
The most important member of the polyester family, PET is widespread in applications ranging from packaging to fibres and fabrics. DuPont is currently preparing to launch a new technology to produce PET, currently designated Process NG-3. The company is building a $10m (£7.1m) pilot plant to test the process at medium-scale, says DuPont’s chief technology officer, Joseph Miller, and expects to begin designing a full-scale plant in around 18 months’ time. ‘NG-3 is a new technology for polymerisation which will require new plants,’ says Miller. ‘But we have also developed a process that can be retrofitted into existing plants and allow low-investment increases in capacity and quality while decreasing manufacturing costs.’
Meanwhile, DuPont is changing the sourcing of its raw materials. The most dramatic recent example is propanediol. A starting material for polypropylene terephthalate, which has a similar structure but different properties from PET, propanediol has been the subject of research collaboration between DuPont and biotech pioneer Genencor International. The two firms’ researchers have devised a method to convert glucose, derived from corn, directly into propanediol using a genetically-engineered micro-organism. ‘This technology will provide the lowest possible cost route to a future key intermediate,’ Miller claims.
Specialities still figure in DuPont’s plans, however. Looking into the second quarter of the century, Miller predicts that the company’s portfolio, while similar to today’s, will have a customer-oriented slant which would be familiar to BASF’s process engineers. ‘Our major technology platforms, such as the nylon and polyester molecules, will remain, but the product lines we build out of them will look very little like today’s,’ he says. ‘Our increased ability to understand and control the structure – and thus the function – of those and many other molecules, will allow us to invent whole new classes of materials.’
Wonder materials that became bulk commodities
Acrylics: Acrylics are typified by polymethyl methacrylate, or Perspex, originally used to make aircraft canopies. Acrylics are now commonly encountered as the clear sheets used for overhead projections.
Nylon: A whole family of polyamides originally discovered in the 1930s. First used as a replacement for parachute silk, then in applications from clothes to bearings and gears, the last because of its low friction properties. Related to nylon are the aramids, which remain speciality materials. They include Kevlar and Nomex and are used in applications ranging from bulletproof jackets to composite panels for aircraft.
ABS: Polymer of acrylonitrile, butadiene, and styrene. Began life as a high-performance engineering plastic. Now forming your car’s bumpers, domestic water pipes and bodies for consumer products such as phones.
Polycarbonate: Originally a high-value replacement for glass due to its light weight and resistance to shattering. Now, it’s what compact discs are made of – and even more familiar as the clear plastic sheeting available in the local DIY shop.
Stuart Nathan is deputy editor of Process Engineering.