13 October, 2025
FROM PRODUCTION TO BED: HOW FLEXIBLE POLYURETHANE FOAM IS MADE FOR MATTRESSES
Flexible polyurethane (PU) foam is the material behind most of today’s comfortable and supportive mattresses. Known for its lightweight structure, durability, and flexibility, PU foam has revolutionised how we sleep. But how exactly is it made — and why is it so essential to the bedding industry?
Let’s take a look at the journey of foam, from its chemical production to the finished mattress on your bed.
The Chemistry Behind Comfort
Every polyurethane foam starts with a carefully balanced chemical reaction between polyols and diisocyanates, both of which are often derived from crude oil.
The main diisocyanate used in the production of flexible polyurethane foam is TDI (Toluene diisocyanate). Some foams, notably so-called visco-elastic or memory foams, can also be made with MDI (Methylene diphenyl diisocyanate). Moulded foams (often used in seating or pillow applications) are more often made with MDI.
When mixed with polyols, long alcoxyether chains, these chemicals form the fundamental building blocks of polyurethane. When these components are combined with water and small quantities of catalysts and other performance additives, a chemical reaction occurs that creates millions of tiny air cells. The result is flexible polyurethane foam — a material that is light, elastic, and highly resilient.
In this process, the reaction between polyols and isocyanates, initiated by water, produces carbon dioxide gas, which causes the mixture to expand and form a cellular structure. Additives play a key role in controlling the reaction rate and determining the foam’s density, firmness, and mechanical properties, ensuring consistent performance for its intended application.
This process is often compared to baking a cake: the ingredients must be precisely measured, mixed, and cured to achieve the desired texture and performance. A slight change in one ingredient or proportion can completely alter the feel of the finished foam — just as too much sugar or too little flour can change the outcome of a cake.
Foam Production: From Liquid to Solid Block
In modern manufacturing, slabstock foam production is the most common method used for mattress applications. In this continuous process, the liquid chemical components are pumped through dosing streams into a mixing chamber, where they are homogenised with a pin stirrer. Immediately afterwards, the liquid PU mixture is poured onto a moving conveyor belt. The chemical reactions begin shortly after, causing the foam to rise within a rectangular foaming tunnel and then solidify. The fresh foam blocks are cut by the foaming machine into lengths ranging from 15 to 120 metres and subsequently stored in special curing chambers for up to 24 hours. During this time, further chemical reactions occur until the desired properties are achieved. The fully cured blocks are then stored in long-block warehouses for further testing and processing.
Today’s state-of-the-art foam plants employ advanced automated systems to monitor and control each stage of production, ensuring quality, efficiency, and minimal waste. The resulting cured foam is then fabricated into various shapes and sizes, making it suitable for use in bedding, furniture, and other comfort applications.
From Blocks to Mattress Layers
Once cured, the foam is converted into sheets and profiles of varying thickness and hardness levels. These are then combined to form multi-layered mattress cores, offering a balance of comfort and support.
- Softer layers create plushness and relieve pressure points.
- Firmer layers provide structural support.
- High-resilience or memory foams enhance ergonomic performance.
Advanced cutting and contouring techniques also improve airflow and temperature regulation, key to a comfortable sleep.
Certified Quality and Safety
To ensure that mattress foams are safe, durable, and environmentally sound, many European producers participate in the CertiPUR™ certification programme.
CertiPUR™-approved foams are:
Made without harmful substances such as heavy metals or ortho-phthalate plasticisers;
Tested for low emissions to indoor air;
Verified by independent laboratories for compliance with strict European standards.
When consumers see the CertiPUR™ label, they can trust that their foam is tested, safe, and responsibly produced.
Innovation and Sustainability in Foam Production
The polyurethane industry is constantly innovating to reduce its environmental footprint. Manufacturers are increasingly using:
Recycled polyols derived from post-consumer foam waste,
Renewable raw materials with lower carbon footprints, and
Life Cycle Assessment (LCA) tools – such as PUReLCA – to measure and improve sustainability performance.
Emerging chemical recycling technologies even allow old foam to be broken down into its original components, creating new foam for future mattresses — a step towards a more circular economy.
Takeaways
Behind every modern mattress lies an advanced material designed for comfort and performance. Flexible polyurethane foam combines science, precision, and innovation to deliver the support and softness that define quality sleep. From production to bed, it remains one of the most reliable and sustainable materials for the bedding industry.