Technical presentations featured at this year’s spring meeting of the Polyurethane Foam Association looked at how the the US foam industry reduce its environmental burden. Sarah Houlton reports.
They covered a wide range of subjects, including how to manage waste foam to minimise environmental impact; the need for changes to anti-microbial testing; improving the environmental profile of foams and retaining or improving flame retardancy; and finally, the opportunities which natural polyols can offer in polyurethane formulations.
Utilising waste foam
Sara Petty, a senior research scientist at the Green Science Policy Institute, reported on the April meeting of a stakeholder group in Berkeley, California, looking at how waste foam can be managed responsibly.
She explained that the 2013 update to California’s Technical Bulletin 117 made it possible for furniture made with flame retardant-free foam to comply with this smoulder standard, and it is now increasingly available. But what about the FR-filled furniture it replaces?
TB117-2013 has been much more successful in reducing flame retardant use than a ban, Petty said. “Banning chemicals doesn’t work as we just move on to another chemical, which we don’t necessarily understand,” she said. The new standard recognises that fires start in the fabric cover, not the foam, and therefore TB117-2013 focuses on smoulder-resistant upholstery fabrics, allowing flame retardants to be omitted from foams in many cases.
“We didn’t enter the workshop expecting solutions,” Petty said. “The aim was to get stakeholders together to decide where best to focus our energies.” Topics covered in the Berkeley meeting included US municipal waste management and environmental considerations, flexible PU foam and related industries, technologies for FR destruction, and the needs of technology and policy research.
In the US, waste management for old furniture is heavily reliant on landfill. Petty said that FRs such as PBDEs escape from foam into the environment, as they can leach out or form gases. The leachate often reaches water treatment facilities, where it cannot be effectively managed. Where PU foam is recycled, the FRs remain in the foam, and the aim is to mix it with post-industrial trim and other foam known to be FR free. The goal is to dilute the FR content, ideally to 0.1% or lower. This is then used to make bonded carpet cushion, she said.
“We need an end-of-life plan in place, and we should strongly consider
not placing the burden on waste facilities.”
Sara Petty, senior research scientist at the Green Science Policy Institute on end-of-life foam
Destroying FR-containing foam is problematic. Municipal waste incinerators need to be heated above 850°C to fully combust brominated FRs. This temperature is not an issue for cement kilns, but there is a history of feedstocks being incorrectly fed in, leading to lower temperatures. Plasma arc vessels are another alternative, but these cannot handle the scale required in the US, Petty added. A further approach involves supercritical water oxidation, but the pre-processing is much more involved.
Finally, there is a big problem in identifying FR-containing foams, and separating out those that are FR-free.
Petty suggested that solutions will include academic research projects, where the National Science Foundation is providing some funding. Industry will play its part, too. But there is much work still to be done. “No waste treatment options exist that will destroy or remove FRs from flexible PU foam,” she said. “We need an end-of-life plan in place, and we should strongly consider not placing the burden on waste facilities.”
PU foam pink stain problem-solving