Planting the seeds of sustainable PU foam

Posted on 7 May 2024 by The Manufacturer

Creating a truly circular economy that will enable us to meet national and global net zero targets is evidently no easy feat and will require multiple technologies, innovations, and new ways of working, explains Julie Walker, Technical and Manufacturing Manager at Vitafoam.

Getting to this point in the PU foam industry will mean leveraging numerous enabling actions, ranging from using sustainable and recycled materials to extending trim life and pushing the envelope on nascent technologies, such as biomass-balanced polyols and isocyanate production.

While all of these will be critical to creating a sustainable sector, the use of plant-based sources is an especially vital route to drastically cutting down on fossil-fuel based raw material extraction and the emissions from this type of production.

How does it work?

Plant-based (or bio-based) foams are created using polyols from renewable resources, which are long chain hydrocarbons with hydroxyls on, that can be fed into the production of PU based foam. This allows manufacturers to replace a percentage of fossil-fuel based raw materials with an alternative that has a lower carbon footprint.

These bio-polyols can be made from a variety of renewable oils, but at Vita we use sunflower, castor, and soy, as our supply chain has the necessary technology to turn these into the required manufacturing element. Importantly, we make sure that the sources we choose have no harmful environmental impacts.

Creating polyols from renewable sources itself isn’t new but using them to move the PU foam industry away from fossil fuel-based ingredients is an overlooked route to creating a more sustainable manufacturing sector. At Vita, we’ve been using plants to create foam since 2007, when we launched the Origin range of bio-based PU foam.

Plants aren’t the only raw material that can be used as an alternative feedstock in PU foam production. We’ve also explored the use of recycled foam to create re-polyols as well as bio-mass and bio-gas to create polyurethane foam raw material precursors.

This research resulted in Vitafoam’s invention of Novus in the 1980s, which is a foam constructed through mechanical recycling methods. Novus uses foam offcuts which are processed by bonding granulated trim with a binding agent to create a versatile foam with a significant CO2 reduction potential compared to standard foam production.

We also use recycled post-consumer foam mattresses in the production of our Orbis range. To achieve this, we partnered with Dow Chemical on the Renuva Mattress Recycling Program to produce flexible PU foams made from Renuva polyols.

Life cycles and carbon analysis

The environmental benefits of using bio-polyols are multifaceted. On a basic level, the act of growing plants for bio polyols creates oxygen. Also, as a manufacturer we’ve seen how an increased use of bio-polyol and re-polyol materials has positively impacted our Scope 3 emissions, which is vital to creating sustainable supply chains.

Assessing the overall environmental qualities of a product can be tricky and therefore we’ve worked with a third party to develop a holistic Lifecycle Assessment (LCA) model to understand the cradle to gate carbon emissions of foam made from bio-polyols and re-polyols.

When we plugged the information for Orbis (the foam made using recycled mattresses) into the model, we could see a clear reduction in emissions compared to standard foams. With the UK foam grades, the difference in the total global warming potential (GWP) by amount of CO2 produced could be as much 3%. This increases to around 4% for European grades, which are subject to different manufacturing regulations. The GWP figure provides an accurate all-round indicator of the emissions, as it accounts for numerous production factors.

When drilling down into specific areas of the LCA, the difference can be even more stark. For example, the amount of water used to generate the recycled polyol used in Orbis is significantly lower than that used in the production of traditional polyols. In fact, the water intensity reduction is three times more than the carbon reduction. This is important data which complements GWP and helps us when considering future potential water scarcity issues.

The durability of a product is central when considering LCAs, as the more durable it is then the longer it will be in use and therefore the fewer resources will be required to replace it. This is why getting the balance of alternative feedstocks to fossil fuels right is vital, as too many bio or re-polyols could result in a foam that degrades very quickly – thereby negating the benefit of the initially lower emissions profile as more will have to be made.

Our most recent formulas, in which around 13% of the finished foam will contain raw material from renewable resources, is the current optimum as it creates a product with similar levels of durability to an entirely fossil-fuel derived foam. That’s not to say that 13% will always be the limit, and we’re working hard with our suppliers to innovate, test new formulas and increase this proportion without affecting the foam’s performance.

Planting the seeds of sustainable PU foam

Sustainable markets

Maintaining high performance characteristics is crucial, as effective sustainability relies on commercialisation and market support to drive greener technologies. The demand is currently growing and we’re expecting this to increase as awareness of what can be achieved spreads.

Increasing the scale of this technology will also help drive further R&D and build the infrastructure required to turn end-of-life renewable PU foams back into new polyols. The relatively small amount of this type of foam currently in the market means this level of recycling hasn’t been established on an industrial scale yet, although we don’t anticipate that there will be any problem achieving this from our initial work.

Once at this point, we’ll be able to create a fully circular PU foam economy, in which sustainably sourced foams which reduce virgin hydrocarbons use are themselves a sustainable feedstock for tomorrow’s PU foam products.

For more articles like this, visit our Sustainability channel.