Project manager for bioplastics Linda Zellner quoted figures from the European Bioplastics organisation forecasting near-term growth of 20% in this area. But she acknowledged that the bio-based, renewable segment, involving products such as 'green' polyethylene among others, is likely to show the fastest growth.
Perstorp’s particular focus is on polycaprolactone (PCL) technology, derived from caprolactone cyclic esters, which it markets under its Capa brand name. Zellner explained that, although PCLs are derived from petrochemical – rather than renewable – resources, they are fully biodegradable and compostable “under the right conditions”, and can be used as a performance-enhancer in proportions of 10–30% in a blend with a biopolymer such as PLA.
“At the same time, we are in the process of developing new products with bio-based content, which will behave slightly differently,” said Zellner.
PCLs can be used to improve the toughness, tear resistance and impact strength of many different biopolymers. “For example, PLA may be too brittle on its own in certain applications,” she said. “PCLs can also improve biodegradability and sometimes function as a processing aid.”
Zellner stated that Perstorp works with businesses throughout the value chain. “We’ve noted a greater willingness among packaging manufacturers and end users to spend more in order to have sustainable packaging,” she said.
The company has invested in a new UK pilot plant for bioplastics and a new laboratory in Sweden. As well as PLA, key biopolymers in packaging applications include polyhydroxyalkanoates (PHA) and thermoplastic starch.
End-of-life scenarios for biodegradable and compostable packaging remain challenging. But Perstorp said it was encouraged by the growing availability of anaerobic digestion (AD), especially, in Sweden. AD capacity has also been increasing in the UK.