INNOVATIONS | POLYURETHANES


Right: H&S has developed its own technol- ogy and reactor installations for the chemical conversion of flexible and rigid PU foam residues into new polyols


flexible foams could end up back in new mattresses. “We are convinced that polyurethanes have an


important role to play in a circular economy and reducing our impact on the environment,” says Marcel Moeller, Global Marketing & Sustainability Director, Dow Polyurethanes. He says around 30m mattresses are thrown away in Europe every year. “We are addressing the challenge of discarded


mattresses head on,” says Neil Carr, president of Dow Europe, Middle East, Africa, and India. “We have been actively reviewing centrally organised waste collection, dismantling, and recycling systems for end-of-life material for years. France has set an example by creating the EPR scheme and Eco-mobilier is leading the way in mattress and furniture waste collection.”


Mechanical limitations The new development builds on Dow’s existing col- laboration with H&S Anlagentechnik, announced in 2017. H&S has developed its own technology and reactor installations for the chemical conver- sion of flexible and rigid PU foam residues (from production and also post-consumer) into new polyols. “In comparison to previous recycling methods, polyols generated by H&S technology have good reactivity and do not contain primary aromatic amines (methylene and toluene diamine), which are hazardous and not acceptable especially in bedding and upholstery foams,” H&S says. “Polyurethane foam manufacturers of both rigid


Below: BASF has conducted pilot tests for a chemical recycling process for used mattresses


and flexible types are showing a lot of interest in [chemical] recycling technology. For flexible foam, this is because the methods previously used, such as rebound foam for carpet underlay and sports mats, are no longer economically attractive. Applications for mechanically recycled rigid foam, as powder, are limited. Also, since an enormous volume of rigid scrap is generated by processors such as big insulating panels manufacturers,


recycling small amounts ground up as a powder filler cannot use it all. Of course the growing price of polyols also plays a role here.“ H&S has already successfully realised several


projects in this area, including one of the first industrial reactor systems working with post-pro- duction flexible PU foam residues for Ikano in Poland (put into operation in 2013 with a capacity of 2,400 tonnes per year), and a system converting semi-rigid automotive PU foam into polyol in China – this plant, which began production in 2015, was supplied to a large automotive supplier producing headliners, luggage compartment and other components. The company has also delivered various reactors


for aromatic and aliphatic polyester polyols synthesis based on PET and other raw materials around the world. Another “significant” post-con- sumer PU foam recycling project is in the pipeline, said Mila Skokova, Product & Sales Manager, in late January. More details on this project are set to be announced later this year. Capacity of H&S reactor systems is individually designed depending on the customer’s needs. Capacity of recycling systems is up to 3,000 tonnes per year. For polyester polyol systems it is up to 15,000 tonnes per year. Skokova says: “The process is distinguished by a high yield up to 96%. From one tonne of PUR foam, approximately 2.2 tonnes of recovered polyol can be generated. We are using basic polyol or glycol (depending on the technology) to dissolve the PUR. In general, recovered polyols produced by H&S technology can substitute up to 30-40% of original polyols without compromising the quality of the final product, depending on the application. Manufacturing cost of recovered polyols is signifi- cantly lower than the market price of the original polyols and makes realisation of such projects very attractive commercial-wise.”


38 PLASTICS RECYCLING WORLD | January/February 2021 www.plasticsrecyclingworld.com


IMAGE: BASF


IMAGE: H&S


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