The costs of not going green How sustainable are polyurethanes? Daniel Saxton from NexantECA answered the question with some numbers at UTECH Europe
The rigid polyurethane industry has a strong story to tell about its sustainability. These materials are frequently used to insulate buildings, refrigerators and steps along the cold chain. Using polyurethane in these applications is a cost-effective way to insulate and also has lower energy consumption and carbon dioxide production than other materials.
But is this sufficient to ensure their continued use, and what can be done to improve the sustainability of other types of polyurethane? This is important, because science and society have been driving change towards sustainability for several years now.
‘Looking at a time series of average global temperature from 1900, there was a real increase in the rate of temperature change in the 1980s,’ he said. ‘This started the discussion around sustainability and our impact on the world.’ There has been an increase in frequency of the word ‘sustainability’ in books published since 1980.
Using data from Google Trends, he added that there has been a persistently high interest in climate change as a topic within sustainability. The numbers from Google show interest increasing by 11% since 2005.
At the same time, interest in plastic waste, which was consistently running at about 10% of interest in climate change, has leapt by 17% since 2005. This could be a result of society becoming more aware of the problem after China restricted plastics waste imports in 2018. Looking at the data, he said plastic waste and climate change are clearly the most important sustainability topics to the public.
Despite this, he explained that polyurethane insulation is having a positive impact in the construction industry. Research from NexantECA shows that between 1990 and 2020, CO₂ emissions savings from energy efficiency initiatives in commercial and domestic buildings have amounted to 1.5 GT of CO₂ cumulatively since 1990. ‘While polyurethane insulation is not fully responsible, it has certainly contributed to the savings,’ he said.
Other good examples of the sustainable benefits that polyurethanes bring can be found in appliances and their energy efficiency targets, vehicle lightweighting, and moulded foams and coatings and their impact on product lifetime. ‘But this analysis makes it easy to get rose-tinted,’ he said. ‘It’s easy only to look at the good and not the work that still needs to be done.’
The first important area to look at is recycling and recycling rates. ‘This will tell us how PU compares with other polymers, other materials and how the industry is responding to the plastic waste crisis,’ Saxton said. The extent of the opportunity is shown in Fig 1.
‘The recycling rate for polyurethane within the EU is currently about 8%, while for expanded polystyrene (EPS) it is about 33%,’ he said. ‘The 8% rate for polyurethane is predominately made up of recovery and recycling of pre-consumer scrap. Post-consumer recycling is minimal, with rebonded foam the major recycled product. Chemical recycling is an emerging but small part of the PU industry.’