Biodegradable polymers are either made from petrochemicals or from renewable raw materials such as starch, cellulose or maize. In both cases they are compostable, although some polymers that degrade by oxidation and are not fully biodegradable can cause problems in composting processes.
Interest in biodegradable polymers in Europe has been driven partly by the lower costs they attract under packaging legislation.
In the UK, for example, packaging made from biodegradable polymers is classified as "other materials" rather than plastics. Packaging waste recovery notes - the tradable certificates issued under the regime - are more expensive for plastics. And changes to the German packaging ordinance, which came into effect in May, have exempted biodegradable packaging until 2012 from fees charged by the national recycling organisation DSD.
In the USA, the development of plant-based plastics, as well as biofuels and chemical feedstocks, has been driven by the need to reduce oil imports and help farmers diversify into non-food crops. In addition, Far Eastern electronics companies such as Sony and Fujitsu have marketed bioplastic products as made from renewable resources.
The new plastic, Ecovio, is a blend of polylactic acid, a biodegradable polymer produced from maize by Cargill subsidiary NatureWorks LLC, and BASF's own biodegradable plastic Ecoflex, a copolyester derived from petrochemicals.
The move is also a rare example of a major European company showing interest in plant-based polymers or chemical feedstocks. Until now, most progress has been made by US firms such as Dow Chemical, Cargill, DuPont, Archer Daniels Midland and Procter & Gamble (ENDS Report 362, pp 34-35 ). However, earlier this year BP agreed a two-year programme with US firm Metabolix to develop renewable and biodegradable plastics from crops such a switchgrass.
BASF has been involved with oil-based biodegradable plastics for some years, producing Ecoflex since 1998 in an 8,000 tonnes per year plant at its chemical complex at Ludwigshafen, Germany. Early applications included cutlery, compost sacks, agricultural films - where it could be ploughed into the soil after use - and coated or laminated papers used for fast food packaging, drinks cartons and beverage cups (ENDS Report 315, pp 29-32 ).
According to BASF, consumption of biodegradable polymers in Europe rose from 8,000 tonnes to 45,000 tonnes between 1998 and 2003. The company predicts the world market for biodegradable plastics will grow by more than 20% annually over the next five years.
Sales of Ecoflex rose 35% in 2001 compared with the previous year. A second plant, producing 6,000 tonnes per year, is due to start up at Schwarzheide, Germany, early next year.
Although Ecovio can also be used to produce flexible films, the addition of additives can make it rigid and suitable for applications such as mobile phone housings and yoghurt pots.
The polymer will be launched in Europe next spring, followed by the USA and Asia later in the year.
BASF is keen to promote the green credentials of polylactic acid (PLA), the plant-based polymer in Ecovio, as "largely" carbon dioxide-neutral when composted. But it says the maize used to produce the PLA will be genetically-modified or GM-free "depending on the market".
NatureWorks recently launched a new service which offers customers PLA certified as non-GM or, for larger customers with long-term contracts, identity-preserved non-GM PLA which has been kept separate from the rest of its production.
NatureWorks nearly doubled its sales in the first half of 2005 versus the same period in 2004, largely due to strong European growth for plant-based plastics. In the past year the company has signed a deal with French retailer Auchan and Belgian grocery group Delhaize. The material is also being used in new applications for plant-based materials such as loyalty cards, often replacing PVC.
NatureWorks claims the stability of maize prices versus petrochemical-based polymers such as PET has made PLA price competitive for the past 12 months, encouraging customers to seek long-term contracts to ensure a more stable raw material supply and cost position for packaging materials.