Producers are looking for a process that provides rapid foaming at room temperature.
Researchers at the University of Liège, Belgium have developed a process for producing bio-based polyurethane (PU) foams, which are recyclable and free of isocyanate, at room temperature.
Their process uses a rapid foaming technology. The work has been published in the Journal of the American Chemical Society and a patent has been filed for the technology.
It builds on work published by the team in 2022, in which they introduced what they claim to be the first recyclable isocyanate-free PU foam manufacturing process using water to produce carbon dioxide, the foaming agent. The development was described as the ‘simplest and most economical system ever reported.’
‘This technology mimics the foaming of conventional PU, but without the isocyanates. It is based on the use of water and a catalyst added to the formulation composed of acrylic carbonates and amines. Part of the cyclic carbonate is transformed into carbon dioxide which expands the matrix,’ said research director Christophe Detrembleur. This foaming process requires thermal treatment and is suited to isocyanate-free PU foams in heated moulds.
However, many producers are looking for a process that provides rapid foaming at room temperature, and the newly patented work meets this demand. Said to be simple, modular, robust and very easy to implement, the researchers say that virtually all applications of PU foams, both rigid and flexible, can be produced using the technology without the need for an external heat source for their production.
‘Moreover, foams with a high bio-based content (70-90%) can easily be produced in less than two minutes,’ said researcher Maxime Bourguignon. The team is now working to implement the process with PU producers.
Efforts to develop sustainable PU, a material that has application in products ranging from thermal insulation to furnishing and footwear, have been ongoing. In 2020, researchers from the University of California San Diego, in collaboration with Algenisis Materials, developed a PU made from algae oil. The material specifically met needs for shoe midsoles and the footbed of flip-flops.
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