Flexible Polyurethane Foam Industry Issues
Sustainability
Through ongoing efforts, the flexible polyurethane foam (FPF) industry is elevating the sustainability of its products and manufacturing processes. Manufacturers and suppliers to the industry are carefully evaluating sustainability practices at every step of the flexible foam life cycle, from precursor chemicals through recycling foam products at the end of their useful life.
Top: Approximately 85%* of the carpet cushion sold in North America is made from recycled flexible polyurethane foam. Virtually all post-industrial foam scrap (and a growing percentage of post consumer foam scrap) is mechanically recycled into carpet cushion.
Left: New technologies in chemical recycling are making it possible to use foam recovered from old mattresses to make products such as cell phone cases.
*Source: Carpet Cushion Council
PFA’s Sustainability Committee has been tasked with helping the industry evaluate sustainability technologies and put them into practice.
The committee began its work by reviewing the 17 goals for sustainable development created by the United Nations’ Department of Economic and Social Affairs. From those, the committee identified ones that could be addressed by an industry association, and then narrowed the list down to four initial topics for concentrated focus.
Flexible Polyurethane Foam: Key Sustainability Issues
Closed Loop Recycling Of Foam
Flexible polyurethane foam can be recycled in a number of ways, including mechanical recycling and chemical recycling. The ultimate goal is to recycle old foam into new foam with the same performance properties. This is challenging for a thermoset plastic like FPF. But researchers continue to make progress.
Renewable And Sustainable Raw Materials
Suppliers to the FPF industry have offered bio-content raw materials for a number of years, and the industry has embraced these. There is extensive research into developing new bio-feedstocks.
Minimizing Transportation Footprint
Because foam is bulky, transportation is a challenge. The industry is addressing this with compression, logistics, and other strategies.
Improved Operating Efficiencies
Foam manufacturers continually work to improve production processes to be more sustainable and more cost competitive. This can include reducing waste, recycling materials internally, and reducing emissions.
Traditionally, The Foam Industry Has Been Proactive On Sustainability
Among its accomplishments:
- Elimination of the use of chlorofluorocarbons (CFCs), which had been shown to deplete the earth’s vitally important ozone layer, from FPF manufacturing processes.
- NESHAP Compliance Ahead of Schedule. The FPF industry pioneered solutions for reducing emissions of the raw material methylene chloride to meet the EPA’s National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations.
- Voluntary Phaseout of PBDE (And Other Flame Retardants): In January 2005, PFA manufacturer members voluntarily phased out the use of pentaBDE flame retardants in the manufacture of FPF for use in home furnishings cushioning applications. (Process required nearly two years of conversion work.) Since then, flame retardant chemicals have been eliminated from most other flexible foam applications, except where required by regulations, such as in the automotive industry.
Current Sustainable Technologies In Flexible Foam
The flexible polyurethane foam industry currently employs or is researching a variety of technologies and practices designed to improved its sustainability. Some have been in place for many years; others are now emerging.
Established: Carpet Cushion
Recycing
A Recycling Success Story
Flexible polyurethane foam (FPF) products are highly recyclable. In fact, the FPF industry has one of the most successful recycling records in the world.
In the United States, nearly all manufacturing scrap is collected and recycled.
Instead of being routed into landfills, FPF scrap and recovered materials are easily recycled into useful consumer products such as bonded carpet cushion (sometimes called “rebond”), which accounts for approximately 85% of all carpet cushion products sold in the U.S., according to the Carpet Cushion Council.
A cylinder of bonded polyurethane foam is “peeled” into thin sheets for carpet cushion.
This is an example of mechanical recycling. Scrap foam is ground into small pieces. The pieces are then bonded together with adhesives and heat, producing a large cylinder of foam. The cylinder is then sliced into thin sheets for use as carpet cushion.
Bonded polyurethane foam carpet cushion boasts both recycle content and recyclability. Scrap collectors and processors can be found in most major metropolitan areas.
With a typical recycled content of around 90%, bonded polyurethane carpet cushion primarily uses scrap foam generated from various manufacturing processes and recovered post-consumer waste from products at the end of their useful life, including mattresses and carpet cushion.
In addition to its recycling advantages, bonded polyurethane carpet cushion contributes to the sustainability equation by extending the lifecycle of carpet under which it is installed. Although it’s a recycled product, bonded cushion is affordable and has superior performance because it can have higher density for better support. Many carpet manufacturers require that their carpet be installed over a high performance cushion in order to validate the carpet warranty.
According to an estimate by the Carpet Cushion Council, approximately 1.2 billion pounds of combined post-industrial and post-consumer foam scrap is diverted annually from landfills to the manufacture of carpet cushion.
Quality bonded carpet cushion can extend the useful life of carpet. Many carpet manufacturers require that their products are installed over quality cushion to validate carpet warranties.
Expanding: Mattress Recycling
In addition to product innovation and quality testing, the mattress and foam industries are actively involved in researching ways to address what happens to mattresses at the end of their life cycle. The Mattress Recycling Council (MRC) is a nonprofit organization formed by the mattress industry to operate recycling programs in those states that have enacted mattress recycling laws.
The program is currently running in California, Connecticut, Oregon, and Rhode Island and is known as Bye Bye Mattress to consumers. Each state’s program is funded by a recycling fee collected when consumers buy a mattress or box spring.
The Council is committed to educating the mattress industry about state’s mattress recycling laws and assisting retailers and manufacturers in complying with those laws. Through its work with local governments, waste management professionals, recyclers and others, it has successfully developed accessible and efficient collection and recycling networks in the program states.
To date, the Mattress Recycling Council has helped recycle more than 15 million mattresses that would have otherwise gone to landfills.
In addition to carpet cushion, there are other markets being explored for mechanically recycled foam, including some upholstery applications, sound insulation, covered pads for gyms and other athletics, and others.
Recycling Foam Back Into Foam
Next Steps
To achieve true closed-loop recycling, flexible polyurethane foam will need to be broken down and then manufactured into foam with comparable properties.
Some plastics are easier to recycle than others. For example, some “thermoplastic” materials can be simply melted down and re-used again. Flexible polyurethane foam, a thermoset material, is more complicated.
The molecular structure of FPF is formed by a chemical reaction between two key components, a polyol and an isocyanate. The chemical bonds are strong, so it takes a specialized process to break it down.
There are several technologies that do versions of this. Each produces different results. Some of these processes could provide true closed-loop recycling, others provide useful end use products or intermediate components, but are not converted back into foam (open loop recycling).
In thermo-mechanical recycling, foam is combined with a catalyst at elevated temperature, and extruded into a new foam product. The resulting product can be a molded foam or a solid thermoplastic polyurethane. These can be use in various applications, but not the same as the original material.
In glycolosis, the chemicals in polyurethane are separated with glycol/dialcohol. The end useful product is a polyol with 40-60% recycled content, providing a partial solution.
In full depolymerization, polyurethane is depolymerized into its original components (isocyanate and polyol). These can be used to produce foam that has similar properties to the original material, which promises closed-loop recycling.
In pyrolysis or in gasification, foam materials are broken down into petrochemicals, the feedstocks from which isocyanates and polyols are made. This would be considered open-loop recycling, although it would lead to the production of new polyols and isocyanates.
A number of organizations are researching these processes, with some now at industrial scale. Work will continue as the industry continues working toward being able to fully recycle its products.
Sustainable Raw Materials
Sustainable
Raw materials for manufacturing flexible polyurethane foam have traditionally come from petrochemicals. However, in the last 20 years, there have been significant advancements in the development of bio-based materials, particularly polyols.
Bio-polyols were originally derived from renewable plants such as soy and castor beans. However, in recent years, a number of new feedstocks for bio-polyols have emerged, including lignin, the compound that gives structural to plants and makes up approximately a third of plant mass. Another emerging source for bio-polyols is recovering carbon dioxide from the atmosphere. Other plant waste resources are also being studied.
Bio-polyols can yield foams with premium properties, including better resistance to yellowing and slightly better mechanical properties such as support factor and dynamic flex fatigue. One limitation of bio-polyols currently is that they cannot completely replace petrochemicals in foam chemistry, although the percentages of bio-polyols in the mix are being increased through more research.
Bio-content is also being developed for other chemistry used in foam production. Catalysts, surfactants, and other additives that improve foam performance are contributing to the sustainability story.
Transportation Managment
Challenges
PFA’s Sustainability Committee is also evaluating issues regarding transportation. Since foam is a bulky product, transportation has long been an area of focus. Trucks that allow foam to be compressed for shipment have long helped with tranportation efficiency. Logistics with chemical deliveries are also continually reviewed to reduce transportation costs (and improved overall sustainability).
Market dynamics have also made it possible to reduce transportation costs: the advent of “bed in a box” foam mattresses, which are compressed and can be shipped directly to consumers, has also allowed the foam industry to make transportation delivery more efficient.
Operational Efficiency
Challenges
Continuous improvement processes in foam manufacturing are also reducing emissions and waste. As already discussed, virtually all scrap foam is recovered and recycled. Recycling of other materials has also increased. For example, chemicals used for cleaning equipment are recovered and returned to their suppliers for reprocessing.
Related Resources
Related
Video: How Foam Is Made
See how foam is manufactured, including details on sustainable materials and recycling.
Carpet Cushion Council
The trade association for carpet cushion manufacturers.
Mattress Recycling Council
News on recycling efforts across the United States. Details on state regulations, recycling centers, and uses for recycled materials.
PFA Technical Presentations
Many presentations at our Technical Sessions at PFA meetings focus on sustainability issues.